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Abstract
Rapid manufacturing of high purity fused silica glass micro-optics using a filament-based glass 3D printer has been demonstrated. A multilayer 5 × 5 microlens array was printed and subsequently characterized, showing fully dense lenses with uniform focal lengths and good imaging performance. A surface roughness on the order of Ra = 0.12 nm was achieved. Printing time for each lens was <10 s. Creating arrays with multifocal imaging capabilities was possible by individually varying the number of printed layers and radius for each lens, effectively changing the lens height and curvature. Glass 3D printing is shown in this study to be a versatile approach for fabricating silica micro-optics suitable for rapid prototyping or manufacturing.
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Affiliation(s)
- Chunxin Liu
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
- Nobula3D AB, Stockholm, Sweden
| | - Taras Oriekhov
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
- Nobula3D AB, Stockholm, Sweden
| | - Cherrie Lee
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Clarissa M. Harvey
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Michael Fokine
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
- Nobula3D AB, Stockholm, Sweden
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Wu Y, Dong X, Wang X, Xiao J, Sun Q, Shen L, Lan J, Shen Z, Xu J, Du Y. Fabrication of Large-Area Silicon Spherical Microlens Arrays by Thermal Reflow and ICP Etching. Micromachines (Basel) 2024; 15:460. [PMID: 38675271 PMCID: PMC11052383 DOI: 10.3390/mi15040460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
In this paper, we proposed an efficient and high-precision process for fabricating large-area microlens arrays using thermal reflow combined with ICP etching. When the temperature rises above the glass transition temperature, the polymer cylinder will reflow into a smooth hemisphere due to the surface tension effect. The dimensional differences generated after reflow can be corrected using etching selectivity in the following ICP etching process, which transfers the microstructure on the photoresist to the substrate. The volume variation before and after reflow, as well as the effect of etching selectivity using process parameters, such as RF power and gas flow, were explored. Due to the surface tension effect and the simultaneous molding of all microlens units, machining a 3.84 × 3.84 mm2 silicon microlens array required only 3 min of reflow and 15 min of ICP etching with an extremely low average surface roughness Sa of 1.2 nm.
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Affiliation(s)
- Yu Wu
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Xianshan Dong
- Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory, Guangzhou 511370, China;
| | - Xuefang Wang
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Junfeng Xiao
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Quanquan Sun
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Lifeng Shen
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Jie Lan
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Zhenfeng Shen
- Shanghai Aerospace Control Technology Institute, Shanghai 201109, China (L.S.); (J.L.); (Z.S.)
| | - Jianfeng Xu
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
| | - Yuqingyun Du
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; (Y.W.); (J.X.); (Y.D.)
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Sun ZJ, Liu YQ, Wan JY, Liu XQ, Han DD, Chen QD, Zhang YL. Reconfigurable Microlens Array Enables Tunable Imaging Based on Shape Memory Polymers. ACS Appl Mater Interfaces 2024; 16:9581-9592. [PMID: 38332526 DOI: 10.1021/acsami.4c01030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Microlens arrays (MLAs) with a tunable imaging ability are core components of advanced micro-optical systems. Nevertheless, tunable MLAs generally suffer from high power consumption, an undeformable rigid body, large and complex systems, or limited focal length tunability. The combination of reconfigurable smart materials with MLAs may lead to distinct advantages including programmable deformation, remote manipulation, and multimodal tunability. However, unlike photopolymers that permit flexible structuring, the fabrication of tunable MLAs and compound eyes (CEs) based on transparent smart materials is still rare. In this work, we report reconfigurable MLAs that enable tunable imaging based on shape memory polymers (SMPs). The smart MLAs with closely packed 200 × 200 microlenses (40.0 μm in size) are fabricated via a combined technology that involves wet etching-assisted femtosecond laser direct writing of MLA templates on quartz, soft lithography for MLA duplication using SMPs, and the mechanical heat setting for programmable reconfiguration. By stretching or squeezing the shape memory MLAs at the transition temperature (80 °C), the size, profiles, and spatial distributions of the microlenses can be programmed. When the MLA is stretched from 0 to 120% (area ratio), the focal length is increased from 116 to 283 μm. As a proof of concept, reconfigurable MLAs and a 3D CE with a tunable field of view (FOV, 160-0°) have been demonstrated in which the thermally triggered shape memory deformation has been employed for tunable imaging. The reconfigurable MLAs and CEs with a tunable focal length and adjustable FOV may hold great promise for developing smart micro-optical systems.
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Affiliation(s)
- Zhi-Juan Sun
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Yu-Qing Liu
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Emitting Materials and Technology of Ministry of Education, National Demonstration Center for Experimental Physics Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Jia-Yi Wan
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Xue-Qing Liu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Dong-Dong Han
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Qi-Dai Chen
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Yong-Lai Zhang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
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Kim HM, Shin YK, Seo MH. Development of Shape Prediction Model of Microlens Fabricated via Diffuser-Assisted Photolithography. Micromachines (Basel) 2023; 14:2171. [PMID: 38138339 PMCID: PMC10745055 DOI: 10.3390/mi14122171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023]
Abstract
The fabrication of microlens arrays (MLAs) using diffuser-assisted photolithography (DPL) has garnered substantial recent interest owing to the exceptional capabilities of DPL in adjusting the size and shape, achieving high fill factors, enhancing productivity, and ensuring excellent reproducibility. The inherent unpredictability of light interactions within the diffuser poses challenges in accurately forecasting the final shape and dimensions of microlenses in the DPL process. Herein, we introduce a comprehensive theoretical model to forecast microlens shapes in response to varying exposure doses within a DPL framework. We establish a robust MLA fabrication method aligned with conventional DPL techniques to enable precise shape modulation. By calibrating the exposure doses meticulously, we generate diverse MLA configurations, each with a distinct shape and size. Subsequently, by utilizing the experimentally acquired data encompassing parameters such as height, radius of curvature, and angles, we develop highly precise theoretical prediction models, achieving R-squared values exceeding 95%. The subsequent validation of our model encompasses the accurate prediction of microlens shapes under specific exposure doses. The verification results exhibit average error rates of approximately 2.328%, 7.45%, and 3.16% for the height, radius of curvature, and contact angle models, respectively, all of which were well below the 10% threshold.
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Affiliation(s)
- Ha-Min Kim
- School of Biomedical Convergence Engineering, Pusan National University, 49 Busandaehak-ro, Mulgeum-eup, Yangsan-si 50612, Republic of Korea;
| | - Yoo-Kyum Shin
- Department of Information Convergence Engineering, Pusan National University, 49 Busandaehak-ro, Mulgeum-eup, Yangsan-si 50612, Republic of Korea;
| | - Min-Ho Seo
- School of Biomedical Convergence Engineering, Pusan National University, 49 Busandaehak-ro, Mulgeum-eup, Yangsan-si 50612, Republic of Korea;
- Department of Information Convergence Engineering, Pusan National University, 49 Busandaehak-ro, Mulgeum-eup, Yangsan-si 50612, Republic of Korea;
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Shan S, Li J, Liu P, Li Q, Wang X, Li X. A Microlens Array Grating for Miniature Multi-Channel Spectrometers. Sensors (Basel) 2023; 23:8381. [PMID: 37896475 PMCID: PMC10610974 DOI: 10.3390/s23208381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/11/2023] [Accepted: 09/19/2023] [Indexed: 10/29/2023]
Abstract
Most existing multi-channel spectrometers are constructed by physically stacking single-channel spectrometers, resulting in their large size, high weight, and limited number of channels. Therefore, their miniaturization is urgently needed. In this paper, a microlens array grating is designed for miniature multi-channel spectrometers. A transmissive element integrating microlens arrays and gratings, the MLAG, enables simultaneous focusing and dispersion. Using soft lithography, the MLAG was fabricated with a deviation of less than 2.2%. The dimensions are 10 mm × 10 mm × 4 mm with over 2000 available units. The MLAG spectrometer operates in the 400-700 nm wavelength range with a resolution of 6 nm. Additionally, the designed MLAG multi-channel spectrometer is experimentally verified to have independently valid cells that can be used in multichannel spectrometers. The wavelength position repeatability deviation of each cell is about 0.5 nm, and the repeatability of displacement measurements by the chromatic confocal sensor with the designed MLAG multi-channel spectrometer is less than 0.5 μm.
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Affiliation(s)
- Shuonan Shan
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (S.S.); (J.L.); (P.L.); (X.W.)
| | - Jingwen Li
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (S.S.); (J.L.); (P.L.); (X.W.)
- Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
| | - Peiyuan Liu
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (S.S.); (J.L.); (P.L.); (X.W.)
| | - Qiaolin Li
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (S.S.); (J.L.); (P.L.); (X.W.)
| | - Xiaohao Wang
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (S.S.); (J.L.); (P.L.); (X.W.)
- Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
| | - Xinghui Li
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (S.S.); (J.L.); (P.L.); (X.W.)
- Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
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6
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Wu M, Jiang L, Li X, Xiang Z, Yi P, Liu Y, Zhang L, Li X, Wang Z, Zhang X. Microheater-Integrated Microlens Array for Robust Rapid Fog Removal. ACS Appl Mater Interfaces 2023; 15:41092-41100. [PMID: 37599436 DOI: 10.1021/acsami.3c07262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
In extreme environments, fog formation on a microlens array (MLA) surface results in a device failure. One reliable solution for fog removal is to heat the surface using a microheater. However, due to the surface interference, the combination of these two microdevices remains elusive. In this study, we introduce lift-off and electroless plating into femtosecond laser processing to fabricate a microheater integrated MLA (μH-MLA) on the same substrate with high light transmittance, durability, and fog removal efficiency. Laser-induced micro-nano grooves enable the microheater to be tightly coupled with the MLA and have high heating performance, thus maintaining a stable performance for over 24 h during continuous operation as well as under long time ultrasonic vibration and mechanical friction. With a rapid response time (τ0.5) of 17 s and a high working temperature of 188 °C, the μH-MLA removed fog that covers the entire face within 14 s. Finally, we prove the use of this fabrication method in large areas and curved surface environments. This study provides a flexible, stable, and economical method to integrate micro-optical and microelectrical devices.
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Affiliation(s)
- Mengnan Wu
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Lan Jiang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaowei Li
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhikun Xiang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Peng Yi
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yang Liu
- Institute of Micro-Nano Optoelectronics and Terahertz Technology, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Leyi Zhang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xibiao Li
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhi Wang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiangyu Zhang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
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Wang J, Li J, Wu Y, Yu H, Cui L, Sun M, Chiang PY. A 256 × 256 LiDAR Imaging System Based on a 200 mW SPAD-Based SoC with Microlens Array and Lightweight RGB-Guided Depth Completion Neural Network. Sensors (Basel) 2023; 23:6927. [PMID: 37571709 PMCID: PMC10422305 DOI: 10.3390/s23156927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/30/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023]
Abstract
Light detection and ranging (LiDAR) technology, a cutting-edge advancement in mobile applications, presents a myriad of compelling use cases, including enhancing low-light photography, capturing and sharing 3D images of fascinating objects, and elevating the overall augmented reality (AR) experience. However, its widespread adoption has been hindered by the prohibitive costs and substantial power consumption associated with its implementation in mobile devices. To surmount these obstacles, this paper proposes a low-power, low-cost, single-photon avalanche detector (SPAD)-based system-on-chip (SoC) which packages the microlens arrays (MLAs) and a lightweight RGB-guided sparse depth imaging completion neural network for 3D LiDAR imaging. The proposed SoC integrates an 8 × 8 SPAD macropixel array with time-to-digital converters (TDCs) and a charge pump, fabricated using a 180 nm bipolar-CMOS-DMOS (BCD) process. Initially, the primary function of this SoC was limited to serving as a ranging sensor. A random MLA-based homogenizing diffuser efficiently transforms Gaussian beams into flat-topped beams with a 45° field of view (FOV), enabling flash projection at the transmitter. To further enhance resolution and broaden application possibilities, a lightweight neural network employing RGB-guided sparse depth complementation is proposed, enabling a substantial expansion of image resolution from 8 × 8 to quarter video graphics array level (QVGA; 256 × 256). Experimental results demonstrate the effectiveness and stability of the hardware encompassing the SoC and optical system, as well as the lightweight features and accuracy of the algorithmic neural network. The state-of-the-art SoC-neural network solution offers a promising and inspiring foundation for developing consumer-level 3D imaging applications on mobile devices.
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Affiliation(s)
- Jier Wang
- State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, China; (J.W.); (M.S.)
| | - Jie Li
- State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, China; (J.W.); (M.S.)
| | - Yifan Wu
- College of Electronics and Information Engineering, Tongji University, Shanghai 201804, China
| | - Hengwei Yu
- State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, China; (J.W.); (M.S.)
| | - Lebei Cui
- State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, China; (J.W.); (M.S.)
| | - Miao Sun
- State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, China; (J.W.); (M.S.)
| | - Patrick Yin Chiang
- State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203, China; (J.W.); (M.S.)
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Meena Narayana Menon D, Pugliese D, Giardino M, Janner D. Laser-Induced Fabrication of Micro-Optics on Bioresorbable Calcium Phosphate Glass for Implantable Devices. Materials (Basel) 2023; 16:ma16113899. [PMID: 37297033 DOI: 10.3390/ma16113899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023]
Abstract
In this study, a single-step nanosecond laser-induced generation of micro-optical features is demonstrated on an antibacterial bioresorbable Cu-doped calcium phosphate glass. The inverse Marangoni flow of the laser-generated melt is exploited for the fabrication of microlens arrays and diffraction gratings. The process is realized in a matter of few seconds and, by optimizing the laser parameters, micro-optical features with a smooth surface are obtained showing a good optical quality. The tunability of the microlens' dimensions is achieved by varying the laser power, allowing the obtaining of multi-focal microlenses that are of great interest for three-dimensional (3D) imaging. Furthermore, the microlens' shape can be tuned between hyperboloid and spherical. The fabricated microlenses exhibited good focusing and imaging performance and the variable focal lengths were measured experimentally, showing good agreement with the calculated values. The diffraction gratings obtained by this method showed the typical periodic pattern with a first-order efficiency of about 5.1%. Finally, the dissolution characteristics of the fabricated micropatterns were studied in a phosphate-buffered saline solution (PBS, pH = 7.4) demonstrating the bioresorbability of the micro-optical components. This study offers a new approach for the fabrication of micro-optics on bioresorbable glass, which could enable the manufacturing of new implantable optical sensing components for biomedical applications.
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Affiliation(s)
- Devanarayanan Meena Narayana Menon
- Department of Applied Science and Technology (DISAT) and RU INSTM, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Diego Pugliese
- Department of Applied Science and Technology (DISAT) and RU INSTM, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Matteo Giardino
- Department of Applied Science and Technology (DISAT) and RU INSTM, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Davide Janner
- Department of Applied Science and Technology (DISAT) and RU INSTM, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
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Mu H, Smith D, Katkus T, Gailevičius D, Malinauskas M, Nishijima Y, Stoddart PR, Ruan D, Ryu M, Morikawa J, Vasiliev T, Lozovski V, Moraru D, Ng SH, Juodkazis S. Polarisation Control in Arrays of Microlenses and Gratings: Performance in Visible-IR Spectral Ranges. Micromachines (Basel) 2023; 14:798. [PMID: 37421030 DOI: 10.3390/mi14040798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 07/09/2023]
Abstract
Microlens arrays (MLAs) which are increasingly popular micro-optical elements in compact integrated optical systems were fabricated using a femtosecond direct laser write (fs-DLW) technique in the low-shrinkage SZ2080TM photoresist. High-fidelity definition of 3D surfaces on IR transparent CaF2 substrates allowed to achieve ∼50% transmittance in the chemical fingerprinting spectral region 2-5 μm wavelengths since MLAs were only ∼10 μm high corresponding to the numerical aperture of 0.3 (the lens height is comparable with the IR wavelength). To combine diffractive and refractive capabilities in miniaturised optical setup, a graphene oxide (GO) grating acting as a linear polariser was also fabricated by fs-DLW by ablation of a 1 μm-thick GO thin film. Such an ultra-thin GO polariser can be integrated with the fabricated MLA to add dispersion control at the focal plane. Pairs of MLAs and GO polarisers were characterised throughout the visible-IR spectral window and numerical modelling was used to simulate their performance. A good match between the experimental results of MLA focusing and simulations was achieved.
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Affiliation(s)
- Haoran Mu
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Daniel Smith
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Tomas Katkus
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Darius Gailevičius
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, LT-10222 Vilnius, Lithuania
| | - Mangirdas Malinauskas
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, LT-10222 Vilnius, Lithuania
| | - Yoshiaki Nishijima
- Department of Electrical and Computer Engineering, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
- Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Paul R Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Dong Ruan
- School of Engineering, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Meguya Ryu
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 3, 1-1-1 Umezono, Tsukuba 305-8563, Japan
| | - Junko Morikawa
- WRH Program International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- CREST-JST, School of Materials and Chemical Technology, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Taras Vasiliev
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Str. 60, 01602 Kyiv, Ukraine
| | - Valeri Lozovski
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Str. 60, 01602 Kyiv, Ukraine
| | - Daniel Moraru
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Research Institute of Electronics, Shizuoka University, Johoku 3-5-1, Hamamatsu 432-8011, Japan
| | - Soon Hock Ng
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Melbourne Centre for Nanofabrication, 151 Wellington Road, Clayton, VIC 3168, Australia
| | - Saulius Juodkazis
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- WRH Program International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
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Lv Z, Huang Y, Liu Z. Analysis and Suppression of Crosstalk Stray Light in a Microlens Array Scanning and Searching System. Micromachines (Basel) 2023; 14:336. [PMID: 36838037 PMCID: PMC9965550 DOI: 10.3390/mi14020336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/11/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
The microlens array (MLA) system can aid in realizing fast beam deflection owing to the lateral displacement between arrays. The MLA system has the advantages of miniaturization and good functionality. However, during system operation, crosstalk beams are generated between each microlens array unit, introducing additional stray light, thus affecting the imaging contrast of the system. Therefore, this study uses the matrix operation method to trace the paraxial ray to trace the optical system and analyzes the generation mechanism of crosstalk stray light in the MLA system. Furthermore, this study proposes a crosstalk suppression method based on a stop array to reasonably suppress stray light. Finally, an example of an infrared array scanning infrared optical system is considered so as to verify the correctness and feasibility of the proposed crosstalk stray light suppression method. Therefore, this paper introduces the stray light suppression principle to guide the optical design process of the system, providing a theoretical basis for the design and analysis of the microlens array scanning and search system.
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11
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Luan S, Xu P, Zhang Y, Xue L, Song Y, Gui C. Flexible Superhydrophobic Microlens Arrays for Humid Outdoor Environment Applications. ACS Appl Mater Interfaces 2022; 14:53433-53441. [PMID: 36394606 PMCID: PMC9716522 DOI: 10.1021/acsami.2c17128] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
A microlens array (MLA) is an essential optical imaging device in the applications of augmented and virtual realities. The imaging of MLA would become blurry in a humid outdoor atmosphere. While the incorporation of superhydrophobicity to MLA would prevent the adhesion of droplets, the complex structure and the multiple fabrication process reduce the capability of optical imaging of MLA. Herein, a flexible superhydrophobic MLA with good optical imaging capability is successfully fabricated by the combination of 3D direct laser writing (DLW) and soft lithography. 3D DLW allows the fabrication of MLA with a hierarchical pillar array (h-MLA) in one step, which ensures good optical properties of the resulting polydimethylsiloxane (PDMS) h-MLA. The resulting h-MLAs with pitches ranging between 50 and 100 μm are superhydrophobic from which water droplets slide away at a sliding angle smaller than 15.6° and bounce off from the surface. Meanwhile, the hierarchical pillar array has a limited impact on the imaging capability and the field of view of h-MLA. With an optimized pitch of 60 μm, h-MLA has a transparency as good as MLA. Moreover, PDMS h-MLA retains excellent optical and superhydrophobic properties when bent and in an extremely humid environment. We believe that the proposed h-MLA could find applications in outdoor environments.
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Affiliation(s)
- Shiyi Luan
- School
of Power and Mechanical Engineering, Wuhan
University, Wuhan430072, China
| | - Peng Xu
- School
of Power and Mechanical Engineering, Wuhan
University, Wuhan430072, China
| | - Yurong Zhang
- The
Institute of Technological Sciences, Wuhan
University, Wuhan430072, China
| | - Longjian Xue
- School
of Power and Mechanical Engineering, Wuhan
University, Wuhan430072, China
- The
Institute of Technological Sciences, Wuhan
University, Wuhan430072, China
| | - Yi Song
- The
Institute of Technological Sciences, Wuhan
University, Wuhan430072, China
- School
of Microelectronic, Wuhan University, Wuhan430072, China
| | - Chengqun Gui
- The
Institute of Technological Sciences, Wuhan
University, Wuhan430072, China
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12
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Yuan W, Cheung CF. Characterization of Surface Topography Variation in the Ultra-Precision Tool Servo-Based Diamond Cutting of 3D Microstructured Surfaces. Micromachines (Basel) 2021; 12:mi12121448. [PMID: 34945298 PMCID: PMC8703575 DOI: 10.3390/mi12121448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/11/2021] [Accepted: 11/18/2021] [Indexed: 11/16/2022]
Abstract
Previous models of the relative tool-work vibration are not generalized to represent the surface generation mechanism in the ultra-precision tool servo-based diamond cutting (UTSDC) of three-dimensional (3D) microstructured surfaces. This is due to the fact that the tool-work vibration in UTSDC is no longer a steady harmonic vibration with a constant amplitude but is influenced by the tool motion along the thrust direction. In this paper, dynamic modeling of the cutting system is presented for the characterization of surface topography variation in UTSDC of a microlens array considering the tool-work vibration as an underdamped vibration. The natural frequency and damping ratio of the cutting system are determined by the data-dependent systems (DDS) method. Based on the analysis of the surface profile and cutting force signals, it is found that the tool-work vibration is significantly enhanced in the cut-in process when the cutting speed increases. The simulation results show that the proposed dynamic model can well-determine root-mean-squares RMS values of the surface primary profile and the dynamic force acting on the force sensor. The dynamic model provides insight into the formation of the surface topography variation in UTSDC of 3D microstructured surfaces, and the model might be applied in self-optimized machining systems in the future.
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13
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Zhang W, Yan W, Zheng H, Zhao C, Liu D. Laser-Engineered Superhydrophobic Polydimethylsiloxane for Highly Efficient Water Manipulation. ACS Appl Mater Interfaces 2021; 13:48163-48170. [PMID: 34582179 DOI: 10.1021/acsami.1c09194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Low-cost, high-quality, and large-area superhydrophobic surfaces are in high demand. This study demonstrates laser-engineered polydimethylsiloxane (PDMS) as a platform for versatile and highly efficient water manipulation. The fabrication process consists of two steps: patterning PDMS with arrayed microlenses and laser pulse scanning. The obtained PDMS is superhydrophobic and exhibits excellent chemical resistance, UV stability, pressure robustness, and substantial mechanical durability. Notably, there is no significant change in the water contact angles after storage in air for 14 months. Microstructural analysis revealed that the sample contained stable nanostructured inorganics such as crystalline silicon, silicon carbide, and sp3-like carbon. The superhydrophobic surface was demonstrated to have versatile and wide applications in oil/water separation and water collection.
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Affiliation(s)
- Wangyang Zhang
- Institute of Novel Semiconductors, State Key Laboratory of Crystal Materials, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, P. R. China
| | - Weishan Yan
- Institute of Novel Semiconductors, State Key Laboratory of Crystal Materials, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, P. R. China
| | - Haonian Zheng
- Institute of Novel Semiconductors, State Key Laboratory of Crystal Materials, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, P. R. China
| | - Chaopeng Zhao
- Institute of Novel Semiconductors, State Key Laboratory of Crystal Materials, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, P. R. China
| | - Duo Liu
- Institute of Novel Semiconductors, State Key Laboratory of Crystal Materials, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, P. R. China
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14
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Abstract
Microlens arrays (MLAs) are the key components of miniaturized optical systems. To meet the stringent requirements for their application in humid environments, achieving waterproof properties in these objects is an urgent task. It is noteworthy that conventional methods of microlens production usually sacrifice optical performance for stable superhydrophobicity by increasing the surface roughness of the microlens. In this paper, a large area artificial compound eye (ACE) is efficiently fabricated by combining photolithography and inkjet printing. The added micropillars separated the outside droplet from the microlens, and the water droplet was afterward suspended on the top of micropillars. Furthermore, the micropillars enabled superhydrophobicity (at a contact angle above 150°) and low surface adhesion (at a sliding angle of ∼2.8°) of the microlens without affecting its optical performance. Furthermore, when released from the height of 1 and 2 cm, the droplets were fully detached from the surface without sticking. The surface of the ACE was shown to have relatively stable nonwettability due to a small spacing between the micropillars. This means that tuning the morphology and spacing between micropillars allows one to noticeably improve the surface nonwettability stability. Finally, the performance of the fabricated optical system was demonstrated in a water washing experiment. Therefore, the findings of present study may open up the prospects for significant advancement in superhydrophobicity of the optical systems without affecting their imaging performance for real outdoor applications.
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Affiliation(s)
- Jiang Li
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, 712100, China
| | - Wenjun Wang
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710054, China
| | - Ruixiang Zhu
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, 712100, China
| | - Yuxiang Huang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, 712100, China
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15
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Yuan W, Cai Y, Xu C, Pang H, Cao A, Fu Y, Deng Q. Fabrication of Multifocal Microlens Array by One Step Exposure Process. Micromachines (Basel) 2021; 12:mi12091097. [PMID: 34577740 PMCID: PMC8469672 DOI: 10.3390/mi12091097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 01/26/2023]
Abstract
Microlenses can be widely used in integrated micro-optical systems. However, in some special applications, such as light field imaging systems, multifocal microlens arrays (MLA) are expected to improve imaging resolution. For the fabrication of multifocal MLA, the traditional fabrication method is no longer applicable. To solve this problem, a fabrication method of multifocal MLA by a one step exposure process is proposed. Through the analyses and research of photoresist AZ9260, the nonlinear relationship between exposure dose and exposure depth is established. In the design of the mask, the mask pattern is corrected according to the nonlinear relationship to obtain the final mask. The continuous surface of the multifocal MLA is fabricated by the mask moving exposure. The experimental results show that the prepared multifocal MLA has high filling factor and surface fidelity. What is more, this method is simple and efficient to use in practical applications.
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Affiliation(s)
- Wei Yuan
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Yajuan Cai
- School of Information Science and Technology, Southwest Jiao Tong University, Chengdu 610031, China;
| | - Cheng Xu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Hui Pang
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Axiu Cao
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
- Correspondence: (A.C.); (Y.F.); Tel.: +86-028-8510-1178 (A.C.); +86-1520-834-0157 (Y.F.)
| | - Yongqi Fu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.)
- Correspondence: (A.C.); (Y.F.); Tel.: +86-028-8510-1178 (A.C.); +86-1520-834-0157 (Y.F.)
| | - Qiling Deng
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
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16
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Kaewkes A, Manuskiatti W, Cembrano KA, Wanitphakdeedecha R. Treatment of abdominal striae distensae in Fitzpatrick skin types IV to V using a 1064-nm picosecond laser with a fractionated microlens array. Lasers Surg Med 2021; 54:129-137. [PMID: 34420222 DOI: 10.1002/lsm.23471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/21/2021] [Accepted: 08/08/2021] [Indexed: 11/11/2022]
Abstract
BACKGROUND Striae distensae are atrophic dermal scars that can cause psychosocial distress among affected patients. Despite numerous available therapeutic modalities, no gold standard treatment has been established. OBJECTIVE To evaluate the long-term efficacy and safety of a fractional 1064-nm picosecond laser for the treatment of striae alba in individuals with dark skin types. MATERIALS AND METHODS Twenty volunteers with Fitzpatrick skin types IV-V who presented with striae alba were enrolled. Subjects were treated with a fractional 1064-nm picosecond laser for four sessions at 4-week intervals. The skin texture, average melanin index (MI), and melanin variation score were assessed using Antera 3D® before treatment, at 1 month after the second treatment, and at 1, 3, and 6 months after the last treatment. Two independent investigators evaluated clinical improvement by comparing pretreatment and posttreatment photographs. The patient satisfaction rates were likewise assessed. Adverse effects were recorded during the entire study period. RESULTS Significant improvement of skin texture was seen at 1 month after the final treatment (p < 0.001) and continuously improved until the 6-month follow-up visit (p = 0.003). The average MI significantly increased at 1 month after the final treatment (p < 0.001), whereas the melanin variation score decreased throughout the follow-up period. Investigator assessment at the 6-month follow-up revealed that 90% of subjects had moderate to marked improvement of striae appearance. Only two of 20 subjects (10%) developed transient postinflammatory hyperpigmentation (PIH) after laser treatment. CONCLUSION Fractional picosecond 1064-nm laser is effective and well-tolerated for the treatment of striae alba in dark-skinned individuals with a low incidence of PIH.
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Affiliation(s)
- Arisa Kaewkes
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Woraphong Manuskiatti
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kathryn Anne Cembrano
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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17
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Tian F, Hu J, Yang W. GEOMScope: Large Field-of-view 3D Lensless Microscopy with Low Computational Complexity. Laser Photon Rev 2021; 15:2100072. [PMID: 34539926 PMCID: PMC8445384 DOI: 10.1002/lpor.202100072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Indexed: 05/12/2023]
Abstract
Imaging systems with miniaturized device footprint, real-time processing speed and high resolution three-dimensional (3D) visualization are critical to broad biomedical applications such as endoscopy. Most of existing imaging systems rely on bulky lenses and mechanically refocusing to perform 3D imaging. Here, we demonstrate GEOMScope, a lensless single-shot 3D microscope that forms image through a single layer of thin microlens array and reconstructs objects through an innovative algorithm combining geometrical-optics-based pixel back projection and background suppressions. We verify the effectiveness of GEOMScope on resolution target, fluorescent particles and volumetric objects. Comparing to other widefield lensless imaging devices, we significantly reduce the required computational resource and increase the reconstruction speed by orders of magnitude. This enables us to image and recover large volume 3D object in high resolution with near real-time processing speed. Such a low computational complexity is attributed to the joint design of imaging optics and reconstruction algorithms, and a joint application of geometrical optics and machine learning in the 3D reconstruction. More broadly, the excellent performance of GEOMScope in imaging resolution, volume, and reconstruction speed implicates that geometrical optics could greatly benefit and play an important role in computational imaging.
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Affiliation(s)
- Feng Tian
- Department of Electrical and Computer Engineering, University of California, Davis, CA 95616, USA
| | - Junjie Hu
- Department of Electrical and Computer Engineering, University of California, Davis, CA 95616, USA
| | - Weijian Yang
- Department of Electrical and Computer Engineering, University of California, Davis, CA 95616, USA
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18
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Phan HL, Yi J, Bae J, Ko H, Lee S, Cho D, Seo JM, Koo KI. Artificial Compound Eye Systems and Their Application: A Review. Micromachines (Basel) 2021; 12:847. [PMID: 34357257 DOI: 10.3390/mi12070847] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/08/2021] [Accepted: 07/15/2021] [Indexed: 12/24/2022]
Abstract
The natural compound eye system has many outstanding properties, such as a more compact size, wider-angle view, better capacity to detect moving objects, and higher sensitivity to light intensity, compared to that of a single-aperture vision system. Thanks to the development of micro- and nano-fabrication techniques, many artificial compound eye imaging systems have been studied and fabricated to inherit fascinating optical features of the natural compound eye. This paper provides a review of artificial compound eye imaging systems. This review begins by introducing the principle of the natural compound eye, and then, the analysis of two types of artificial compound eye systems. We equally present the applications of the artificial compound eye imaging systems. Finally, we suggest our outlooks about the artificial compound eye imaging system.
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19
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Palawisuth S, Manuskiatti W, Apinuntham C, Wanitphakdeedecha R, Cembrano KAG. Quantitative assessment of the long-term efficacy and safety of a 1064-nm picosecond laser with fractionated microlens array in the treatment of enlarged pores in Asians: A case-control study. Lasers Surg Med 2021; 54:348-354. [PMID: 34233039 PMCID: PMC9291000 DOI: 10.1002/lsm.23449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2021] [Indexed: 12/02/2022]
Abstract
Background Enlarged facial pores are one of the common skin signs of photoaging that patients seek treatment for. However, objective data and long‐term assessment on the efficacy and safety of therapeutic procedures for this condition are limited. Objective To objectively evaluate the efficacy and safety of a 1064‐nm picosecond laser with microlens array (MLA) for pore tightening. Methods Twenty‐five patients with enlarged pores received three treatments with a 1064‐nm picosecond laser coupled with MLA at 4‐week intervals. Patients were evaluated using objective (measurement of pore volume using three‐dimensional photography) and subjective (clinical evaluation by two blinded dermatologists) assessments at baseline and at the 1‐, 3‐, and 6‐month follow‐ups. Adverse effects were also recorded during each visit. Results After three treatments, there was a significant reduction of pore size from baseline (p < 0.001). The improvement in pore size appearance significantly continued from the 1‐month to the 6‐month follow‐up visits (p = 0.013). The total average pore size was 1.15652 ± 0.614322 and 0.8087 ± 0.50515 at baseline and at 6 months after the final treatment, respectively, resulting in an average of 30% reduction in pore size. No cases of dyspigmentation, textural alteration, or scarring were documented. Conclusion Fractional 1064‐nm picosecond laser appears to be effective and safe for reducing pore size in Asians with minimal transient side effects.
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Affiliation(s)
- Siriwan Palawisuth
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Woraphong Manuskiatti
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chalermkwan Apinuntham
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Kathryn Anne G Cembrano
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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20
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Yuan W, Xu C, Xue L, Pang H, Cao A, Fu Y, Deng Q. Integrated Double-Sided Random Microlens Array Used for Laser Beam Homogenization. Micromachines (Basel) 2021; 12:mi12060673. [PMID: 34207625 PMCID: PMC8229250 DOI: 10.3390/mi12060673] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/03/2021] [Accepted: 06/06/2021] [Indexed: 11/25/2022]
Abstract
Double microlens arrays (MLAs) in series can be used to divide and superpose laser beam so as to achieve a homogenized spot. However, for laser beam homogenization with high coherence, the periodic lattice distribution in the homogenized spot will be generated due to the periodicity of the traditional MLA, which greatly reduces the uniformity of the homogenized spot. To solve this problem, a monolithic and highly integrated double-sided random microlens array (D-rMLA) is proposed for the purpose of achieving laser beam homogenization. The periodicity of the MLA is disturbed by the closely arranged microlens structures with random apertures. And the random speckle field is achieved to improve the uniformity of the homogenized spot by the superposition of the divided sub-beams. In addition, the double-sided exposure technique is proposed to prepare the rMLA on both sides of the same substrate with high precision alignment to form an integrated D-rMLA structure, which avoids the strict alignment problem in the installation process of traditional discrete MLAs. Then the laser beam homogenization experiments have been carried out by using the prepared D-rMLA structure. The laser beam homogenized spots of different wavelengths have been tested, including the wavelengths of 650 nm (R), 532 nm (G), and 405 nm (B). The experimental results show that the uniformity of the RGB homogenized spots is about 91%, 89%, and 90%. And the energy utilization rate is about 89%, 87%, 86%, respectively. Hence, the prepared structure has high laser beam homogenization ability and energy utilization rate, which is suitable for wide wavelength regime.
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Affiliation(s)
- Wei Yuan
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.); (L.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Cheng Xu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.); (L.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Li Xue
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.); (L.X.)
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Hui Pang
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
| | - Axiu Cao
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
- Correspondence: (A.C.); (Y.F.); Tel.: +86-028-8510-1178 (A.C.); +86-1520-834-0157 (Y.F.)
| | - Yongqi Fu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China; (W.Y.); (C.X.); (L.X.)
- Correspondence: (A.C.); (Y.F.); Tel.: +86-028-8510-1178 (A.C.); +86-1520-834-0157 (Y.F.)
| | - Qiling Deng
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China; (H.P.); (Q.D.)
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21
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Li S, Shang X, Chen Y, Su X, Hao H, Liu H, Zhang Y, Ni H, Niu Z. Wet-Etched Microlens Array for 200 nm Spatial Isolation of Epitaxial Single QDs and 80 nm Broadband Enhancement of Their Quantum Light Extraction. Nanomaterials (Basel) 2021; 11:1136. [PMID: 33925761 DOI: 10.3390/nano11051136] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 11/24/2022]
Abstract
Uniform arrays of three shapes (gauss, hat, and peak) of GaAs microlenses (MLs) by wet-etching are demonstrated, ∼200 nm spatial isolation of epitaxial single QDs embedded (λ: 890–990 nm) and broadband (Δλ∼80 nm) enhancement of their quantum light extraction are obtained, which is also suitable for telecom-band epitaxial QDs. Combined with the bottom distributed Bragg reflector, the hat-shaped ML forms a cavity and achieves the best enhancement: extraction efficiency of 26%, Purcell factor of 2 and single-photon count rate of 7×106 counts per second at the first lens; while the gauss-shaped ML shows a broader band (e.g., longer λ) enhancement. In the MLs, single QDs with featured exciton emissions are observed, whose time correlations prove single-photon emission with multi-photon probability g(2)(0)=0.02; some QDs show both biexciton XX and exciton X emissions and exhibit a perfect cascade feature. This work could pave a step towards a scalable array of QD single-photon sources and the application of QD photon-pair emission for entanglement experiments.
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22
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Zhang F, Yang Q, Bian H, Hou X, Chen F. Rapid Fabrication of Large-Area Concave Microlens Array on ZnSe. Micromachines (Basel) 2021; 12:mi12040458. [PMID: 33921624 PMCID: PMC8072650 DOI: 10.3390/mi12040458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/30/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022]
Abstract
A rapid and single-step method for the fabrication of a zinc selenide (ZnSe) concave microlens array through the high-speed line-scanning of a femtosecond laser pulse is presented. Approximately 1.1 million microlenses, with minimized volume and high transparency at wavelengths between approximately 0.76–20 μm were fabricated within 36 min. More importantly, the size of the microlenses can be controlled by adjusting the laser power. Their high-quality infrared optical performance was also demonstrated. This method holds great promise for the development of ZnSe-based micro-optical devices.
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Affiliation(s)
- Fan Zhang
- State Key Laboratory for Manufacturing System Engineering, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (F.Z.); (X.H.)
| | - Qing Yang
- School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
| | - Hao Bian
- State Key Laboratory for Manufacturing System Engineering, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (F.Z.); (X.H.)
- Correspondence: (H.B.); (F.C.); Tel.: +86-029-8266-8420 (F.C.)
| | - Xun Hou
- State Key Laboratory for Manufacturing System Engineering, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (F.Z.); (X.H.)
| | - Feng Chen
- State Key Laboratory for Manufacturing System Engineering, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (F.Z.); (X.H.)
- Correspondence: (H.B.); (F.C.); Tel.: +86-029-8266-8420 (F.C.)
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23
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Manuskiatti W, Punyaratabandhu P, Tantrapornpong P, Yan C, Cembrano KAG. Objective and Long-Term Evaluation of the Efficacy and Safety of a 1064-nm Picosecond Laser With Fractionated Microlens Array for the Treatment of Atrophic Acne Scar in Asians. Lasers Surg Med 2020; 53:899-905. [PMID: 33326626 DOI: 10.1002/lsm.23368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/12/2020] [Accepted: 11/29/2020] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVE Fractional 1064-nm picosecond-domain laser has recently been utilized for the treatment of atrophic acne scars and showed promising results. However, data on the safety and efficacy of this procedure in dark-skinned patients are limited. This prospective, self-controlled study was conducted to objectively evaluate the safety and efficacy of a 1064-nm picosecond laser coupled with a microlens array (MLA) for the treatment of atrophic acne scars on Asian skin. STUDY DESIGN/MATERIALS AND METHODS Twenty-six subjects of Fitzpatrick skin types (FSTs) III and IV with atrophic acne scars were enrolled. All subjects were treated with a 1064-nm picosecond laser (spot size of 8 mm, fluence of 1.0 J/cm2 , a repetition rate of 10 Hz) in combination with the MLA handpiece for an average of three passes, for 6 monthly sessions. Objective (measurement of scar volume using three-dimensional (3D) photography and skin roughness analysis using ultraviolet A-light video camera) and subjective (clinical evaluation by two blinded dermatologists) assessments were obtained at baseline and at 1, 3, and 6 months after the final treatment. RESULTS Statistically significant reduction of the scar volume from baseline at 1, 3, and 6 months after the final treatment were observed by 3D photography and ultraviolet A-light video camera. At the 6-month follow-up, 50% (13 of 26) of the subjects were rated as having at least 50% improvement of the scars. The rate of improvement significantly increased from the 1-month follow-up to the 6-month follow-up (P = 0.013). Similarly, at the 6-month follow-up, the scar volume (P = 0.024) and skin roughness (P = 0.001) also significantly improved, in comparison with the baseline. Mild postinflammatory hyperpigmentation (PIH) was observed to develop in approximately 18% of all the treatment sessions. All cases of PIH were temporary and resolved within 4 weeks on average. CONCLUSIONS The 1064-nm picosecond laser with MLA is a safe therapeutic alternative for the treatment of atrophic acne scars in dark-skinned individuals. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- Woraphong Manuskiatti
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Preawphan Punyaratabandhu
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Ploypailin Tantrapornpong
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Chadakan Yan
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Kathryn Anne G Cembrano
- Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
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Lee JH, Chang S, Kim MS, Kim YJ, Kim HM, Song YM. High-Identical Numerical Aperture, Multifocal Microlens Array through Single-Step Multi-Sized Hole Patterning Photolithography. Micromachines (Basel) 2020; 11:mi11121068. [PMID: 33266141 PMCID: PMC7761445 DOI: 10.3390/mi11121068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 11/28/2020] [Accepted: 11/29/2020] [Indexed: 01/20/2023]
Abstract
Imaging applications based on microlens arrays (MLAs) have a great potential for the depth sensor, wide field-of-view camera and the reconstructed hologram. However, the narrow depth-of-field remains the challenge for accurate, reliable depth estimation. Multifocal microlens array (Mf-MLAs) is perceived as a major breakthrough, but existing fabrication methods are still hindered by the expensive, low-throughput, and dissimilar numerical aperture (NA) of individual lenses due to the multiple steps in the photolithography process. This paper reports the fabrication method of high NA, Mf-MLAs for the extended depth-of-field using single-step photolithography assisted by chemical wet etching. The various lens parameters of Mf-MLAs are manipulated by the multi-sized hole photomask and the wet etch time. Theoretical and experimental results show that the Mf-MLAs have three types of lens with different focal lengths, while maintaining the uniform and high NA irrespective of the lens type. Additionally, we demonstrate the multi-focal plane image acquisition via Mf-MLAs integrated into a microscope.
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25
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Tran MT, Oldenbourg R. An experimental method to characterize the relationship between aperture image and ray directions in microscope optics. Microsc Res Tech 2020; 84:668-674. [PMID: 33089583 DOI: 10.1002/jemt.23625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/08/2020] [Indexed: 11/05/2022]
Abstract
We propose a direct experimental method to calibrate the relationship between ray directions in object space and their positions in the aperture plane of a light field microscope. The calibration improves the interpretation of light field images, which contain information from both types of image planes, the field plane and the aperture plane of the ray path in the microscope. Our method is based on the diffraction of line gratings of known periodicities and provides accurate results with subpixel resolution. The method can be custom-tailored to most any optical configuration, including standard light microscopy setups, whenever correct mapping between ray parameters in the object/image plane and the aperture plane is needed.
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Affiliation(s)
- Mai Thi Tran
- College of Engineering and Computer Science, VinUniversity, Hanoi, Vietnam.,Marine Biological Laboratory, Woods Hole, Massachusetts, USA
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26
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Yong J, Bian H, Yang Q, Hou X, Chen F. Mini-Review on Bioinspired Superwetting Microlens Array and Compound Eye. Front Chem 2020; 8:575786. [PMID: 33134276 PMCID: PMC7552737 DOI: 10.3389/fchem.2020.575786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/26/2020] [Indexed: 11/24/2022] Open
Abstract
Microlens arrays (MLAs) and MLA-based artificial compound eyes (ACEs) are the important miniaturized optical components in modern micro-optical systems. However, their optical performance will seriously decline once they are wetted by water droplets (such as fog, dew, and rain droplets) or are polluted by contaminations in a humid environment. In this mini-review, we summarize the research works related to the fabrication of superwetting MLAs and ACEs and show how to integrate superhydrophobic and superoleophobic microstructures with an MLA. The fabrication strategy can be split into two categories. One is the hybrid pattern composed of the MLA domain and the superwetting domain. Another is the direct formation of superwetting nanostructures on the surface of the microlenses. The superhydrophobicity or superoleophobicity endows the MLAs and ACEs with liquid repellence and self-cleaning function besides excellent optical performance. We believe that the superwetting MLAs and ACEs will have significant applications in various optical systems that are often used in the humid or liquid environment.
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Affiliation(s)
- Jiale Yong
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Hao Bian
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Qing Yang
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Xun Hou
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Feng Chen
- State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China
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27
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Lian G, Liu Y, Tao K, Xing H, Huang R, Chi M, Zhou W, Wu Y. Fabrication and Characterization of Curved Compound Eyes Based on Multifocal Microlenses. Micromachines (Basel) 2020; 11:E854. [PMID: 32947769 DOI: 10.3390/mi11090854] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022]
Abstract
Curved compound eyes have generated great interest owing to the wide field of view but the application of devices is hindered for the lack of proper detectors. One-lens curved compound eyes with multi-focal microlenses provide a solution for wide field imaging integrated in a commercial photo-detector. However, it is still a challenge for manufacturing this kind of compound eye. In this paper, a rapid and accurate method is proposed by a combination of photolithography, hot embossing, soft photolithography, and gas-assisted deformation techniques. Microlens arrays with different focal lengths were firstly obtained on a polymer, and then the planar structure was converted to the curved surface. A total of 581 compound eyes with diameters ranging from 152.8 µm to 240.9 µm were successfully obtained on one curved surface within a few hours, and the field of view of the compound eyes exceeded 108°. To verify the characteristics of the fabricated compound eyes, morphology deviation was measured by a probe profile and a scanning electron microscope. The optical performance and imaging capability were also tested and analyzed. As a result, the ommatidia made up of microlenses showed not only high accuracy in morphology, but also imaging uniformity on a focal plane. This flexible massive fabrication of compound eyes indicates great potential for miniaturized imaging systems.
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28
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Bian H, Liang J, Li M, Zhang F, Wei Y. Bioinspired Underwater Superoleophobic Microlens Array With Remarkable Oil-Repellent and Self-Cleaning Ability. Front Chem 2020; 8:687. [PMID: 32850682 PMCID: PMC7417666 DOI: 10.3389/fchem.2020.00687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 07/01/2020] [Indexed: 12/19/2022] Open
Abstract
Underwater superoleophobic microlens array (MLA) has been emerging as a crucial device for its wide applications in ocean optical imaging and sensing, endoscopic surgery, microfluidics and optofluidics, and other biomedical applications. Fabrication of microlens arrays integrated with excellent optical performance as well as underwater superoleophobicity remains a great challenge. In this paper, we report an underwater super oil-repellent MLA on a transparent optical glass substrate via femtosecond laser-induced phase and structural modification and chemical isotropic etching. The fabricated sample simultaneously possesses microlens structures with a smooth surface to enable optical imaging function, and grid-patterned biomimetic micro/nano hierarchical surface structures to produce underwater oil-resistance with a contact angle of 160.0° and a sliding angle of 1.5°. The resultant oil-repellent MLA exhibits underwater superoleophobicity and self-cleaning abilities in water. Meanwhile, it was demonstrated to have impressive imaging capability even after oil contamination. We believe that this novel resultant anti-oil MLA will be helpful for underwater detection and bioscience research, especially in oil polluted underwater workspaces.
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Affiliation(s)
- Hao Bian
- School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Liang
- School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Minjing Li
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Fan Zhang
- School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Yang Wei
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, China
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29
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Allen A, Waldron A, Ottaway JM, Chance Carter J, Michael Angel S. Hyperspectral Raman Imaging Using a Spatial Heterodyne Raman Spectrometer with a Microlens Array. Appl Spectrosc 2020; 74:921-931. [PMID: 32031013 DOI: 10.1177/0003702820906222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A new hyperspectral Raman imaging technique is described using a spatial heterodyne Raman spectrometer (SHRS) and a microlens array (MLA). The new technique enables the simultaneous acquisition of Raman spectra over a wide spectral range at spatially isolated locations within two spatial dimensions (x, y) using a single exposure on a charge-coupled device (CCD) or other detector types such as a complementary metal-oxide semiconductor (CMOS) detector. In the SHRS system described here, a 4 × 4 mm MLA with 1600, 100 µm diameter lenslets is used to image the sample, with each lenslet illuminating a different region of the SHRS diffraction gratings and forming independent fringe images on the CCD. The fringe images from each lenslet contain the fully encoded Raman spectrum of the region of the sample "seen" by the lenslet. Since the SHRS requires no moving parts, all fringe images can be measured simultaneously with a single detector exposure, and in principle using a single laser shot, in the case of a pulsed laser. In this proof of concept paper, hyperspectral Raman spectra of a wide variety of heterogeneous samples are used to characterize the technique in terms of spatial and spectral resolution tradeoffs. It is shown that the spatial resolution is a function of the diameter of the MLA lenslets, while the number of spatial elements that can be resolved is equal to the number of MLA lenslets that can be imaged onto the SHRS detector. The spectral resolution depends on the spatial resolution desired, and the number of grooves illuminated on both diffraction gratings by each lenslet, or combination of lenslets in cases where they are grouped.
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Affiliation(s)
- Ashley Allen
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
| | - Abigail Waldron
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
| | - Joshua M Ottaway
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
| | - J Chance Carter
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
| | - S Michael Angel
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, USA
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30
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Yuan D, Liu B, Zhu Z, Guo Y, Cheng C, Chen H, Gu M, Xu M, Chen L, Liu J, Ouyang X. Directional Control and Enhancement of Light Output of Scintillators by Using Microlens Arrays. ACS Appl Mater Interfaces 2020; 12:29473-29480. [PMID: 32510919 DOI: 10.1021/acsami.0c06779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Scintillators play an important role in the field of nuclear radiation detection, such as nuclear medical imaging, dark matter detection, nuclear physics experiments, and national security. However, the light extraction efficiency of a scintillator with a high refractive index is severely restricted because of the total internal reflection. In this paper, microlens arrays have been applied onto the surface of a cerium-doped lutetium-yttrium oxyorthosilicate scintillator to improve the light extraction efficiency and to control the directivity of the light output. Compared to that of a reference sample, a 3.26-fold enhancement with an emission angle of 45° has been obtained by using microlens arrays with optimal parameters. It was also found that the enhancement ratio can be affected by the refractive index of the microlens, the spacing of individual microlens. The control mechanism of microlens arrays is revealed by a combination of simulations and experiments. X-ray imaging characteristics exhibit an improved gray scale amplitude without any loss of the spatial resolution. The present results suggest that the application of microlens arrays to scintillators is beneficial to the field of nuclear radiation detection.
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Affiliation(s)
- Di Yuan
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Bo Liu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Zhichao Zhu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Yaozhen Guo
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Chuanwei Cheng
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Hong Chen
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Mu Gu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Mengxuan Xu
- State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024, P.R. China
| | - Liang Chen
- State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024, P.R. China
| | - Jinliang Liu
- State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024, P.R. China
| | - Xiaoping Ouyang
- State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi'an 710024, P.R. China
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31
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Chen L, Chen G, Liao L, Chen H. Naked-Eye 3D Display Based on Microlens Array Using Combined Micro-Nano Imprint and UV Offset Printing Methods. Molecules 2020; 25:molecules25092012. [PMID: 32344928 PMCID: PMC7248864 DOI: 10.3390/molecules25092012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/18/2020] [Accepted: 04/23/2020] [Indexed: 11/16/2022] Open
Abstract
An optical film integrating microlens array (MLAs) and 3D micro-graphics is an important way to achieve the naked-eye 3D display effect. The 3D micro-graphics is traditionally generated by the micro-nano imprint technology based on precision engraving mold, which leads to high production cost and low production efficiency, and thus restricts the rapid response to production tasks and large-scale popularization and application. In this study, a process scheme for large-scale printing of 3D micro-graphics using UV offset printing based on presensitized (PS) plate was proposed, matching with the MLAs fabricated by micro-nano imprint process to achieve naked-eye 3D display effect. We used the laser confocal microscope to systematically measure and analyze the geometric and optical performance of the fabricated MLAs in terms of height, curvature radius, center distance, spacing, focal length, and numerical aperture, and evaluated the influence of the publishing resolution of the PS plate on the display effect of 3D micro-graphics. The printing quality and display effect of 3D micro-graphics were further improved by adjusting process parameters such as printing speed and printing pressure. The results of the current study demonstrate that the combined application of micro-nano imprint technology based on precision mold and UV offset printing technology based on PS plate can achieve an excellent naked-eye 3D display effect in 360° all angles, which is efficient, cost-saving, and highly flexible.
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Affiliation(s)
- Linyi Chen
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China; (L.C.); (G.C.)
| | - Guangxue Chen
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China; (L.C.); (G.C.)
| | - Liyu Liao
- YUTO R&D Institute, Shenzhen YUTO Packaging Technology Co., Ltd., Shenzhen 518108, China;
| | - Haozhi Chen
- Guangzhou Financial Service Innovation and Risk Management Research Base, South China University of Technology, Guangzhou 510640, China
- Correspondence:
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Tan JY, Goh G, Kim J. Microfabrication of Microlens by Timed-Development-and-Thermal-Reflow (TDTR) Process for Projection Lithography. Micromachines (Basel) 2020; 11:E277. [PMID: 32156007 DOI: 10.3390/mi11030277] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/24/2020] [Accepted: 03/03/2020] [Indexed: 11/17/2022]
Abstract
This paper presents a microlens fabrication process using the timed-development-and-thermal-reflow process, which can fabricate various types of aperture geometry with a parabolic profile on a single substrate in the same batch of the process. By controlling the development time of the uncrosslinked negative photoresist, a state of partial development of the photoresist is achieved, called the timed development process. The thermal reflow process is followed after the timed development, which allows the photoresist to regain its liquid state to form a smooth meniscus trench surrounded by a crosslinked photoresist sidewall. Microlens with larger aperture size forms deeper trench with constant development time. With constant aperture size, longer developing time shows deeper meniscus trench. The depth of the meniscus trench is modeled in the relationship of the development time and aperture size. Other characteristics for the microlens including the radius of curvature, focal length, and the parabolic surface profile are modeled in the relationship of the microlens thickness and diameter. Microlens with circular, square, and hexagonal bases have been successfully fabricated and demonstrated where each geometry of the lens-bases shows different fill factors of the lens arrays. To test the fabricated lenses, a miniaturized projection lithography scheme was proposed. A centimeter-scale photomask pattern was photo-reduced using the fabricated microlens array with a ratio of 133, where the smallest linewidth was measured as 2.6 µm.
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Li J, Wang W, Mei X, Hou D, Pan A, Liu B, Cui J. Fabrication of Artificial Compound Eye with Controllable Field of View and Improved Imaging. ACS Appl Mater Interfaces 2020; 12:8870-8878. [PMID: 32011852 DOI: 10.1021/acsami.9b20740] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Many arthropods have compound eyes, which are made up of numerous separate visual units (microlenses) or ommatidia. These natural compound eyes have exceptional optical properties such as wide field of view (FOV), low aberration, and fast motion tracking capability. In this paper, a large-scale artificial compound eye (ACE) is fabricated efficiently using a combination of inkjet printing and air-assisted deformation processes. Both size and geometry of the microlens are controlled via superposed drops on the substrate. The simulation results show that the light intensity of the ACE follows a systematic distribution for tilted incident light, which represents a significant improvement, compared to planar distributed microlenses. We then manufacture ACEs with different heights and diameters, and their FOVs are compared with the theoretically predicted results. The measured FOV was 50°-140°. The acceptance angles for the different ACEs are determined, and their relationship with the ratio of height to radius (H/r) of the microlens is investigated in more detail. Furthermore, the imaging properties of the microlenses with different angles of incidences are studied, which suggest a FOV up to 140° and an acceptance angle of about 50°. The microlens captures images even at an angle of incidence of about 60°. The corresponding distortion in both the x and y directions is also investigated. Our findings provide guidelines for the development and fabrication of ACEs with large FOVs and acceptance angles, which may find applications in military, robotics, medical imaging, and astronomy.
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Affiliation(s)
- Jiang Li
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Wenjun Wang
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Xuesong Mei
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Dongxiang Hou
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Aifei Pan
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Bin Liu
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
| | - Jianlei Cui
- State Key Laboratory for Manufacturing System Engineering , Xi'an Jiaotong University , Xi'an 710054 , China
- Shaanxi Key Laboratory of Intelligent Robots , Xi'an Jiaotong University , Xi'an 710049 , China
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Xu M, Zhou Z, Wang Z, Lu H. Self-Assembled Microlens Array with Controllable Focal Length Formed on a Selective Wetting Surface. ACS Appl Mater Interfaces 2020; 12:7826-7832. [PMID: 31944645 DOI: 10.1021/acsami.9b21948] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report a microlens array with a controllable focal length that is based on a selective wetting surface. A substrate modified with a hydrophobic layer that has an array of microholes exhibits different wettability for inside holes (hydrophilic) versus outside holes (hydrophobic). When liquid flows over the surface, a small amount of liquid is adhered to hydrophilic holes and forms a lens-shaped droplet array that self-assembles because of surface tension. A large-sized plano-convex lens array that has good uniformity is obtained via the blade coating method, and controlling the amount of liquid enables control of the focal length. Our self-assembled microlens array has the merits of high optical performance, a simple fabrication procedure, and good mechanical stability, and thus, it has potential applications in imaging processing, light extraction, protein detection, light-emitting diodes, sensors, and displays.
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Affiliation(s)
- Miao Xu
- Academy of Opto-Electric Technology, Special Display and Imaging Technology Innovation Center of Anhui Province, National Engineering Laboratory of Special Display Technology , Hefei University of Technology , Hefei 230009 , China
| | - Zuowei Zhou
- School of Science , Zhejiang University of Science and Technology , Hangzhou 310023 , China
| | - Zi Wang
- Academy of Opto-Electric Technology, Special Display and Imaging Technology Innovation Center of Anhui Province, National Engineering Laboratory of Special Display Technology , Hefei University of Technology , Hefei 230009 , China
| | - Hongbo Lu
- Academy of Opto-Electric Technology, Special Display and Imaging Technology Innovation Center of Anhui Province, National Engineering Laboratory of Special Display Technology , Hefei University of Technology , Hefei 230009 , China
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35
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Huang BY, Huang SY, Chuang CH, Kuo CT. Electrically-Tunable Blue Phase Liquid Crystal Microlens Array Based on a Photoconductive Film. Polymers (Basel) 2020; 12:polym12010065. [PMID: 31906448 PMCID: PMC7023521 DOI: 10.3390/polym12010065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/24/2019] [Accepted: 12/25/2019] [Indexed: 11/16/2022] Open
Abstract
This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive mask resulting in the variation of conductivity is adopted to produce the gradient distribution of the electric field. The reorientations of liquid crystals according to the gradient distribution of the electric field induce the variation of the refractive index. Thus, the incident light experiences the gradient distribution of the refractive index and results in the focusing phenomenon. The study investigates the dependence of lens performance on UV exposure time, the focal length of the lens, and focusing intensities with various incident polarizations. The BPLC microlens array exhibits advantages such as electrically tunability, polarization independence, and fast response time.
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Affiliation(s)
- Bing-Yau Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung 804, Taiwan; (B.-Y.H.); (C.-H.C.)
| | - Shuan-Yu Huang
- Department of Optometry, Chung Shan Medical University, Taichung 402, Taiwan;
- Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung 402, Taiwan
| | - Chia-Hsien Chuang
- Department of Physics, National Sun Yat-sen University, Kaohsiung 804, Taiwan; (B.-Y.H.); (C.-H.C.)
| | - Chie-Tong Kuo
- Department of Physics, National Sun Yat-sen University, Kaohsiung 804, Taiwan; (B.-Y.H.); (C.-H.C.)
- Department of Optometry, Shu-Zen Junior College of Medicine and Management, Kaohsiung 821, Taiwan
- Innovation Incubation Center, Shu-Zen Junior College of Medicine and Management, Kaohsiung 821, Taiwan
- Correspondence:
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36
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Abstract
When a microlens array is aligned and overlaid on an array of patterns with similar periodicity, a highly magnified image of the patterns is observed. This effect, known as moiré magnification, is used to reveal micropatterns that are unresolvable by the naked eye. These patterns are typically limited by print resolution to single color patterns. Here, we demonstrate the potential to selectively reveal more than one set of color patterns. By rotating a microlens array relative to a print containing three overlapping arrays of structural color patterns in 10° steps, each pattern array can be distinctly revealed with minimal crosstalk. This rotation-selective effect of moiré magnification is not seen in conventional microscopy. An advantage is that the moiré images are observable by the naked eye under incoherent illumination. We leverage nanoscale three-dimensional printing by using the two-photon lithography process to produce structural color pattern arrays in a single lithographic step with precisely aligned color pixels. We believe that this work can have applications in precise rotational-alignment tools, covert security documents, and information multiplexing devices.
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Affiliation(s)
- John You En Chan
- Engineering Product Development , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Qifeng Ruan
- Engineering Product Development , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Ray Jia Hong Ng
- Engineering Product Development , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering , National University of Singapore , Singapore 117583 , Singapore
| | - Joel K W Yang
- Engineering Product Development , Singapore University of Technology and Design , Singapore 487372 , Singapore
- Nanofabrication Department , Institute of Materials Research and Engineering , Singapore 138634 , Singapore
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Ma LL, Wu SB, Hu W, Liu C, Chen P, Qian H, Wang Y, Chi L, Lu YQ. Self-Assembled Asymmetric Microlenses for Four-Dimensional Visual Imaging. ACS Nano 2019; 13:13709-13715. [PMID: 31746201 DOI: 10.1021/acsnano.9b07104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Visual imaging that can extract three-dimensional (3D) space or polarization information on the target is essential in broad sciences and technologies. The simultaneous acquisition of them usually demands expensive equipment and sophisticated operations. Therefore, it is of great significance to exploit convenient approaches for four-dimensional (3D and polarization) visual imaging. Here, we present an efficient solution based on self-assembled asymmetric liquid crystal microlenses, with freely manipulated phase profiles and symmetry-breaking properties. Accordingly, characteristics of multifocal functionality and polarization selectivity are exhibited, along with the underlying mechanisms. Moreover, with a specific sample featured by radially increased unit sizes and azimuthally varied domain orientations, the discriminability of four-dimensional information is extracted in a single snapshot, via referring to the coordinates of the clearest images. Demultiplexing of depth/polarization information is also demonstrated. This work will unlock a variety of revolutionary apparatuses and lighten extensive applications.
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Affiliation(s)
- Ling-Ling Ma
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Sai-Bo Wu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
- Institute for Smart Liquid Crystals , JITRI , Changshu 215500 , China
| | - Wei Hu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
- Institute for Smart Liquid Crystals , JITRI , Changshu 215500 , China
| | - Chao Liu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Peng Chen
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
- Institute for Smart Liquid Crystals , JITRI , Changshu 215500 , China
| | - Hao Qian
- State Key Laboratory of Materials Oriented Chemical Engineering, College of Materials Science and Engineering , Nanjing Tech University , Nanjing 210009 , China
| | - Yandong Wang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , Suzhou 215123 , China
| | - Lifeng Chi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials Institute of Functional Nano & Soft Materials (FUNSOM) , Soochow University , Suzhou 215123 , China
| | - Yan-Qing Lu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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Yuan C, Kowsari K, Panjwani S, Chen Z, Wang D, Zhang B, Ng CJX, Alvarado PVY, Ge Q. Ultrafast Three-Dimensional Printing of Optically Smooth Microlens Arrays by Oscillation-Assisted Digital Light Processing. ACS Appl Mater Interfaces 2019; 11:40662-40668. [PMID: 31589018 DOI: 10.1021/acsami.9b14692] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A microlens array has become an important micro-optics device in various applications. Compared with traditional manufacturing approaches, digital light processing (DLP)-based printing enables fabrication of complex three-dimensional (3D) geometries and is a possible manufacturing approach for microlens arrays. However, the nature of 3D printing objects by stacking successive 2D patterns formed by discrete pixels leads to coarse surface roughness and makes DLP-based printing unsuccessful in fabricating optical components. Here, we report an oscillation-assisted DLP-based printing approach for fabrication of microlens arrays. An optically smooth surface (about 1 nm surface roughness) is achieved by mechanical oscillation that eliminates the jagged surface formed by discrete pixels, and a 1-3 s single grayscale ultraviolet (UV) exposure that removes the staircase effect. Moreover, computationally designed grayscale UV patterns allow us to fabricate microlenses with various profiles. The proposed approach paves a way to 3D print optical components with high quality, fast speed, and vast flexibility.
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Affiliation(s)
- Chao Yuan
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Kavin Kowsari
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Sahil Panjwani
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Zaichun Chen
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Dong Wang
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Biao Zhang
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Colin Ju-Xiang Ng
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Pablo Valdivia Y Alvarado
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
| | - Qi Ge
- Digital Manufacturing and Design Centre , Singapore University of Technology and Design , Singapore 487372 , Singapore
- Department of Mechanical and Energy Engineering , Southern University of Science and Technology , Shenzhen 518055 , China
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Li S, Yuan Y, Gao Z, Tan H. High-Accuracy Correction of a Microlens Array for Plenoptic Imaging Sensors. Sensors (Basel) 2019; 19:E3922. [PMID: 31514430 DOI: 10.3390/s19183922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 11/18/2022]
Abstract
Microlens array (MLA) errors in plenoptic cameras can cause the confusion or mismatching of 4D spatio-angular information in the image space, significantly affecting the accuracy and efficiency of target reconstruction. In this paper, we present a high-accuracy correction method for light fields distorted by MLA errors. Subpixel feature points are extracted from the microlens subimages of a raw image to obtain correction matrices and perform registration of the corresponding subimages at a subpixel level. The proposed method is applied for correcting MLA errors of two different categories in light-field images, namely form errors and orientation errors. Experimental results show that the proposed method can rectify the geometric and intensity distortions of raw images accurately and improve the quality of light-field refocusing. Qualitative and quantitative comparisons between images before and after correction verify the performance of our method in terms of accuracy, stability, and adaptability.
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40
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Chen PC, Zhang RH, Chen LT. Using Micromachined Molds, Partial-curing PDMS Bonding Technique, and Multiple Casting to Create Hybrid Microfluidic Chip for Microlens Array. Micromachines (Basel) 2019; 10:E572. [PMID: 31470639 DOI: 10.3390/mi10090572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 11/17/2022]
Abstract
In a previous study, we presented a novel manufacturing process for the creation of 6 × 6 and 8 × 8 microlens arrays (MLAs) comprising lenses with diameters of 1000 μm, 500 μm, and 200 μm within an area that covers 10 mm × 10 mm. In the current study, we revised the manufacturing process to allow for the fabrication of MLAs of far higher density (15 × 15 and 29 × 29 within the same area). In this paper, we detail the revised manufacturing scheme, including the micromachining of molds, the partial-curing polydimethylsiloxane (PDMS) bonding used to fuse the glass substrate and PDMS, and the multi-step casting process. The primary challenges that are involved in creating MLAs of this density were ensuring uniform membrane thickness and preventing leakage between the PDMS and glass substrate. The experiment results demonstrated that the revised fabrication process is capable of producing high density arrays: Design I produced 15 × 15 MLAs with lens diameter of 0.5 mm and fill factor of 47.94%, while Design II produced 29 × 29 MLAs with lens diameter of 0.25 mm and fill factor of 40.87%. The partial-curing PDMS bonding system also proved to be effective in fusing PDMS with glass (maximum bonding strength of approximately six bars). Finally, the redesigned mold was used to create PDMS membranes of high thickness uniformity (coefficient of variance <0.07) and microlenses of high lens height uniformity (coefficient of variance <0.15).
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41
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Abstract
Three-dimensional (3D) single-particle tracking (SPT) is a key tool for studying dynamic processes in the life sciences. However, conventional optical elements utilizing light fields impose an inherent trade-off between lateral and axial resolution, preventing SPT with high spatiotemporal resolution across an extended volume. We overcome the typical loss in spatial resolution that accompanies light-field-based approaches to obtain 3D information by placing a standard microscope coverslip patterned with a multifunctional, light-field metasurface on a specimen. This approach enables an otherwise unmodified microscope to gather 3D information at an enhanced spatial resolution. We demonstrate simultaneous tracking of multiple fluorescent particles within a large 0.5 × 0.5 × 0.3 mm3 volume using a standard epi-fluorescent microscope with submicron lateral and micron-level axial resolution.
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Affiliation(s)
- Aaron L Holsteen
- Geballe Laboratory for Advanced Materials , Stanford University , Stanford , California 94305-4045 , United States
| | - Dianmin Lin
- Geballe Laboratory for Advanced Materials , Stanford University , Stanford , California 94305-4045 , United States
- Department of Electrical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Isaac Kauvar
- Department of Electrical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Gordon Wetzstein
- Department of Electrical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Mark L Brongersma
- Geballe Laboratory for Advanced Materials , Stanford University , Stanford , California 94305-4045 , United States
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42
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Biswas SK, Tanpichai S, Witayakran S, Yang X, Shams MI, Yano H. Thermally Superstable Cellulosic-Nanorod-Reinforced Transparent Substrates Featuring Microscale Surface Patterns. ACS Nano 2019; 13:2015-2023. [PMID: 30698942 DOI: 10.1021/acsnano.8b08477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The recent rapid expansion of thin-film, bendable, and wearable consumer (opto)electronics demands flexible and transparent substrates other than glass. Plastics are the traditional choice, but they require amelioration because of their thermal instability. Here, we report the successful conversion of a soft and thermally vulnerable polymer into a highly thermally stable transparent nanocomposite material. This is achieved by the meticulous choice of a polymer with a glass-transition temperature below 0 °C that gives stable mechanics above room temperature, reinforcing the polymer with a load-bearing hierarchical network of the incredibly strong and stable natural material: cellulose nanorods. Owing to the Pickering emulsification process, the nanocomposites inherit the self-assembled structural hierarchy from the cellulose nanorod-encapsulated resin droplets. The ameliorated nanocomposites have highly desirable high-temperature endurance (∼150-180 °C) in terms of the thermomechanical, thermodimensional, and thermo-optical performance. Any photonic nano- or microstructures can be directly molded on the surface of the nanocomposites in high precision for better light management in photonic and opto-electronic applications. The highlight of this work is the demonstration of a highly thermally stable microlens array on the ameliorated transparent nanocomposite.
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Affiliation(s)
| | - Supachok Tanpichai
- Learning Institute , King Mongkut's University of Technology Thonburi , Bangkok 10140 , Thailand
| | - Suteera Witayakran
- Kasetsart Agricultural and Agro-Industrial Product Improvement Institute , Kasetsart University , Bangkok 10900 , Thailand
| | | | - Md Iftekhar Shams
- Forestry and Wood Technology Discipline , Khulna University , Khulna 9208 , Bangladesh
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Nagato K, Yajima Y, Nakao M. Laser-Assisted Thermal Imprinting of Microlens Arrays-Effects of Pressing Pressure and Pattern Size. Materials (Basel) 2019; 12:ma12040675. [PMID: 30823513 PMCID: PMC6416627 DOI: 10.3390/ma12040675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 11/16/2022]
Abstract
Polymer films with nano- or microstructured surfaces have been widely applied to optical devices, bioplates, and printed electronics. Laser-assisted thermal imprinting (LATI), in which a laser directly heats the surfaces of a mold and a thermoplastic polymer, is one of the high-throughput methods of replicating nano- or microstructures on polymer films. Only the surfaces of the mold and polymer film are heated and cooled rapidly, therefore it is possible to replicate nano- or microstructures on polymer films more rapidly than by using conventional thermal nanoimprinting. In this study, microlens arrays (MLAs) were replicated on polymethylmethacrylate (PMMA) films using LATI, and the effects of the pressing pressure (10-50 MPa) and the pattern size (33- and 5-μm pitch) of the MLA on the filling ratio were investigated by analyzing a microlens replicated using different laser-irradiation times (0.1-2 ms). The filling ratio increased with increasing pressing pressure and laser-irradiation time in the replication of MLAs with varying sizes, while the flow of the PMMA varied with the pressing pressure and laser-irradiation time. It was found that during filling, the shape of the polymer cross-sectional surface demonstrated a double and single peak in the 33- and 5-μm-pitch patterns, respectively. This was because the depth of the heated area in the 33-μm-pitch pattern was smaller than the pattern size, whereas that of the 5-μm-pitch pattern was comparable to (or larger) than the pattern size.
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Affiliation(s)
- Keisuke Nagato
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
| | - Yuki Yajima
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
| | - Masayuki Nakao
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
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44
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Li D, Qiao Z, Walton K, Liu Y, Xue J, Wang B, Jiang X. Theoretical and Experimental Investigation of Surface Topography Generation in Slow Tool Servo Ultra-Precision Machining of Freeform Surfaces. Materials (Basel) 2018; 11:E2566. [PMID: 30562973 DOI: 10.3390/ma11122566] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/12/2018] [Accepted: 12/14/2018] [Indexed: 11/16/2022]
Abstract
Freeform surfaces are featured with superior optical and physical properties and are widely adopted in advanced optical systems. Slow tool servo (STS) ultra-precision machining is an enabling manufacturing technology for fabrication of non-rotationally symmetric surfaces. This work presents a theoretical and experimental study of surface topography generation in STS machining of freeform surfaces. To achieve the nanometric surface topography, a systematic approach for tool path generation was investigated, including tool path planning, tool geometry selection, and tool radius compensation. The tool radius compensation is performed only in one direction to ensure no high frequency motion is imposed on the non-dynamic axis. The development of the surface generation simulation allows the prediction of the surface topography under various tool and machining variables. Furthermore, it provides an important means for better understanding the surface generation mechanism without the need for costly trial and error tests. Machining and measurement experiments of a sinusoidal grid and microlens array sample validated the proposed tool path generation and demonstrated the effectiveness of the STS machining process to fabricate freeform surfaces with nanometric topography. The measurement results also show a uniform topography distribution over the entire surface and agree well with the simulated results.
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45
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Wu H, Wu L, Zhou X, Liu B, Zheng B. Patterning Hydrophobic Surfaces by Negative Microcontact Printing and Its Applications. Small 2018; 14:e1802128. [PMID: 30133159 DOI: 10.1002/smll.201802128] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/15/2018] [Indexed: 05/04/2023]
Abstract
Here, a negative microcontact printing method is developed to form hydrophilic polydopamine (PDA) patterns with micrometer resolution on hydrophobic including perfluorinated surfaces. In the process of the negative microcontact printing, a uniform PDA thin film is first formed on the hydrophobic surface. An activated polydimethylsiloxane (PDMS) stamp is then placed in contact with the PDA-coated hydrophobic surface. Taking advantage of the difference in the surface energy between the hydrophobic surface and the stamp, PDA is removed from the contact area after the stamp release. As a result, a PDA pattern complementary to the stamp is obtained on the hydrophobic surface. By using the negative microcontact printing, arrays of liquid droplets and single cells are reliably formed on perfluorinated surfaces. Microlens array with tunable focal length for imaging studies is further created based on the droplet array. The negative microcontact printing method is expected to be widely applicable in high-throughput chemical and biological screening and analysis.
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Affiliation(s)
- Han Wu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Liang Wu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Xiaohu Zhou
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Baishu Liu
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Bo Zheng
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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46
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Roeder M, Drexler M, Rothermel T, Meissner T, Guenther T, Zimmermann A. Injection Compression Molded Microlens Arrays for Hyperspectral Imaging. Micromachines (Basel) 2018; 9:mi9070355. [PMID: 30424288 PMCID: PMC6082290 DOI: 10.3390/mi9070355] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/12/2018] [Accepted: 07/17/2018] [Indexed: 11/16/2022]
Abstract
In this work, a polymer microlens array (MLA) for a hyperspectral imaging (HSI) system is produced by means of ultraprecision milling (UP-milling) and injection compression molding. Due to the large number of over 12,000 microlenses on less than 2 cm², the fabrication process is challenging and requires full process control. The study evaluates the process chain and optimizes the single process steps to achieve high quality polymer MLAs. Furthermore, design elements like mounting features are included to facilitate the integration into the final HSI system. The mold insert was produced using ultraprecision milling with a diamond cutting tool. The machining time was optimized to avoid temperature drifts and enable high accuracy. Therefore, single immersions of the diamond tool at a defined angle was used to fabricate each microlens. The MLAs were replicated using injection compression molding. For this process, an injection compression molding tool with moveable frame plate was designed and fabricated. The structured mold insert was used to generate the compression movement, resulting in a homogeneous pressure distribution. The characterization of the MLAs showed high form accuracy of the microlenses and the mounting features. The functionality of the molded optical part could be demonstrated in an HIS system by focusing light spectrums onto a CCD image sensor.
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Affiliation(s)
- Marcel Roeder
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany.
- Institute for Micro Integration (IFM), University of Stuttgart, Allmandring 9B, 70569 Stuttgart, Germany.
| | - Marc Drexler
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany.
| | | | - Thomas Meissner
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany.
- Balluff GmbH, Schurwaldstraße 9, 73765 Neuhausen auf den Fildern, Germany.
| | | | - André Zimmermann
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany.
- Institute for Micro Integration (IFM), University of Stuttgart, Allmandring 9B, 70569 Stuttgart, Germany.
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47
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Li S, Zhu Y, Zhang C, Yuan Y, Tan H. Rectification of Images Distorted by Microlens Array Errors in Plenoptic Cameras. Sensors (Basel) 2018; 18:E2019. [PMID: 29937502 DOI: 10.3390/s18072019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 06/21/2018] [Accepted: 06/22/2018] [Indexed: 11/17/2022]
Abstract
A plenoptic cameras is a sensor that records the 4D light-field distribution of target scenes. The surface errors of a microlens array (MLA) can cause the degradation and distortion of the raw image captured by a plenoptic camera, resulting in the confusion or loss of light-field information. To address this issue, we propose a method for the local rectification of distorted images using white light-field images. The method consists of microlens center calibration, geometric rectification, and grayscale rectification. The scope of its application to different sized errors and the rectification accuracy of three basic surface errors, including the overall accuracy and the local accuracy, are analyzed through simulation of imaging experiments. The rectified images have a significant improvement in quality, demonstrating the provision of precise light-field data for reconstruction of real objects.
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48
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Seo M, Seo JM, Cho DD, Koo K. Insect-Mimetic Imaging System Based on a Microlens Array Fabricated by a Patterned-Layer Integrating Soft Lithography Process. Sensors (Basel) 2018; 18:E2011. [PMID: 29932163 DOI: 10.3390/s18072011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/14/2018] [Accepted: 06/21/2018] [Indexed: 11/17/2022]
Abstract
In nature, arthropods have evolved to utilize a multiaperture vision system with a micro-optical structure which has advantages, such as compact size and wide-angle view, compared to that of a single-aperture vision system. In this paper, we present a multiaperture imaging system using a microlens array fabricated by a patterned-layer integrating soft lithography (PLISL) process which is based on a molding technique that can transfer three-dimensional structures and a gold screening layer simultaneously. The imaging system consists of a microlens array, a lens-adjusting jig, and a conventional (charge-coupled device) CCD image sensor. The microlens array has a light screening layer patterned among all the microlenses by the PLISL process to prevent light interference. The three-dimensionally printed jig adjusts the microlens array on the conventional CCD sensor for the focused image. The manufactured imaging system has a thin optic system and a large field-of-view of 100 degrees. The developed imaging system takes multiple images at once. To show its possible applications, multiple depth plane images were reconstructed based on the taken subimages with a single shot.
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49
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Imai T, Shi J, Wong TTW, Li L, Zhu L, Wang LV. High-throughput ultraviolet photoacoustic microscopy with multifocal excitation. J Biomed Opt 2018; 23:1-6. [PMID: 29546734 PMCID: PMC5852316 DOI: 10.1117/1.jbo.23.3.036007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/22/2018] [Indexed: 05/05/2023]
Abstract
Ultraviolet photoacoustic microscopy (UV-PAM) is a promising intraoperative tool for surgical margin assessment (SMA), one that can provide label-free histology-like images with high resolution. In this study, using a microlens array and a one-dimensional (1-D) array ultrasonic transducer, we developed a high-throughput multifocal UV-PAM (MF-UV-PAM). Our new system achieved a 1.6 ± 0.2 μm lateral resolution and produced images 40 times faster than the previously developed point-by-point scanning UV-PAM. MF-UV-PAM provided a readily comprehensible photoacoustic image of a mouse brain slice with specific absorption contrast in ∼16 min, highlighting cell nuclei. Individual cell nuclei could be clearly resolved, showing its practical potential for intraoperative SMA.
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Affiliation(s)
- Toru Imai
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Junhui Shi
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Terence T. W. Wong
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Lei Li
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Liren Zhu
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Lihong V. Wang
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
- Address all correspondence to: Lihong V. Wang, E-mail:
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Mukaida M, Yan J. Fabrication of Hexagonal Microlens Arrays on Single-Crystal Silicon Using the Tool-Servo Driven Segment Turning Method. Micromachines (Basel) 2017; 8:mi8110323. [PMID: 30400513 PMCID: PMC6189949 DOI: 10.3390/mi8110323] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 11/16/2022]
Abstract
Single-crystal silicon microlens arrays are increasingly required in advanced infrared optics. In this study, the authors attempted to fabricate hexagonal microlens arrays, which offer high optical efficiency, on a single-crystal silicon wafer using diamond turning. A tool-servo driven segment turning method was proposed to reduce the dynamic error of the machine tool induced by lenslet edges during lens array cutting. From the results of both cutting experiments and theoretical analysis of the machine tool dynamic error, it was demonstrated that the segment turning method reduced significantly the dynamic errors and led to high form accuracy. As a result, sharp edges among the lenslets were generated precisely and microlens arrays with a form error of ~300 nm peak-to-valley and surface roughness of ~5 nmSa, which meets the requirements of infrared optical systems, were successfully fabricated. The subsurface damage, such as the amorphization of silicon, caused by machining was also reduced.
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Affiliation(s)
- Mao Mukaida
- Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Jiwang Yan
- Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
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