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Cai W, Cheng M, Kong D, Ma Z, Liu YJ. Switchable liquid crystal lenticular microlens arrays based on photopolymerization-induced phase separation for 2D/3D autostereoscopic displays. Opt Express 2024; 32:625-638. [PMID: 38175087 DOI: 10.1364/oe.505002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/10/2023] [Indexed: 01/05/2024]
Abstract
Conventionally, the fabrication of liquid crystal lenticular microlens arrays (LCLMLAs) is complicated and costly. Here, we demonstrate a one-step fabrication technique for LCLMLAs, which is prepared through the photopolymerization-induced phase separation in the LC/polymer composite. The LCLMLAs possess both polarization-dependent and electrically tunable focusing properties. Furthermore, we construct a 14-view 2D/3D switchable autostereoscopic display prototype based on a 2D LCD panel and the prepared LCLMLA, which has a viewing angle of 14° and a crosstalk of 46.2% at the optimal viewing zone. The proposed LCLMLAs have the merits of simple fabrication, large-scale production, and low cost.
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Wang J, McGinty C, Reich R, Finnemeyer V, Clark H, Berry S, Bos P. Process for a Reactive Monomer Alignment Layer for Liquid Crystals Formed on an Azodye Sublayer. Materials (Basel) 2018; 11:ma11071195. [PMID: 30002302 PMCID: PMC6073623 DOI: 10.3390/ma11071195] [Citation(s) in RCA: 6] [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] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 12/05/2022]
Abstract
In this work, the detailed studies of surface polymerization stabilizing liquid crystal formed on an azodye sublayer are presented. The surface localized stabilization is obtained by free-radical polymerization of a dilute solution of a bi-functional reactive monomer (RM) in a liquid crystal (LC) solvent. To optimize the process for surface localized stabilization, we investigate the effects of several process parameters including RM concentration in LC hosts, the types of materials (either RM or LC), the photo-initiator (PI) concentration, ultra-violet (UV) polymerization intensity, and the UV curing temperature. The quality of surface localized stabilization is characterized and/or evaluated by optical microscopy, electro-optical behavior (transmission/voltage curve), the life test, and photo-bleaching. Our results show that, by carefully selecting materials, formulating mixtures, and controlling the polymerizing variables, the RM polymerization can be realized either at the surface or through the bulk. Overall, the combination of surface localized stabilization and photo-alignment offers an elegant and dynamic solution for controlling the alignment for LC, which could play a profound role in almost all liquid crystal optical devices.
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Affiliation(s)
- Junren Wang
- Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Colin McGinty
- Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Robert Reich
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02421, USA.
| | - Valerie Finnemeyer
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02421, USA.
| | - Harry Clark
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02421, USA.
| | - Shaun Berry
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02421, USA.
| | - Philip Bos
- Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
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Jang H, Choi H, Jeong H, Baek S, Han S, Chung DJ, Lee HS. Thermally Crosslinked Biocompatible Hydrophilic Polyvinylpyrrolidone Coatings on Polypropylene with Enhanced Mechanical and Adhesion Properties. Macromol Res 2018; 26:151-6. [DOI: 10.1007/s13233-018-6031-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wang M, Guo Y, Hayes RA, Liu D, Broer DJ, Zhou G. Forming Spacers in Situ by Photolithography to Mechanically Stabilize Electrofluidic-Based Switchable Optical Elements. Materials (Basel) 2016; 9:E250. [PMID: 28773375 PMCID: PMC5502914 DOI: 10.3390/ma9040250] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [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: 02/23/2016] [Revised: 03/12/2016] [Accepted: 03/24/2016] [Indexed: 11/16/2022]
Abstract
Electro-Fluidic Displays (EFD) have been demonstrated to be an attractive technology for incorporation into portable display devices. EFDs have excellent optical efficiency and fast switching enabling video content. Ensuring mechanical stability of EFD display cells is a key challenge and essential for developing large area as well as flexible displays. Although the electro-optic performance of an EFD, unlike a liquid crystal display (LCD), is insensitive to cell-gap, extreme changes in cell-gap can result in irreversible collapse of the cell. Here we use photolithography to develop spacers to prevent cell-gap collapse and provide the required mechanical stability for EFD devices. The spacer is formed directly on the cover plates (ITO/glass) after cell assembly with UV light induced phase separation polymerization in the illuminated area. Phase separation behavior between polar aqueous solution and polymer is closely related to the solubility of acrylate monomers. In this work, polyethylene glycol diacrylate (PEGDA) as cross-linker, 2-hydroxyethyl acrylate (HEA) and acrylic acid or acrylamide as co-monomers are investigated for fabricating the spacers. PEGDA was added to the mixtures in order to increase the mechanical strength of the spacer. The spacers showed excellent performance for cell-gap control in EFD devices.
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Affiliation(s)
- Meihong Wang
- Electronic Paper Display Institute, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China.
| | - Yuanyuan Guo
- Electronic Paper Display Institute, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China.
| | - Robert A Hayes
- Electronic Paper Display Institute, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China.
- Shenzhen Guohua Optoelectronics Tech. Co. Ltd., Shenzhen 518110, China.
| | - Danqing Liu
- Eindhoven University of Technology, Institute for Complex Molecular Systems, Eindhoven 5612AP, The Netherlands.
| | - Dirk J Broer
- Eindhoven University of Technology, Institute for Complex Molecular Systems, Eindhoven 5612AP, The Netherlands.
| | - Guofu Zhou
- Electronic Paper Display Institute, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China.
- Shenzhen Guohua Optoelectronics Tech. Co. Ltd., Shenzhen 518110, China.
- Academy of Shenzhen Guohua Optoelectronics, Shenzhen 518110, China.
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Abstract
Self-replicating molecules, in particular RNA, have long been assumed as key to origins of life on Earth. This notion, however, is not very secure since the reduction of life's complexity to self-replication alone relies on thermodynamically untenable assumptions. Alternative, earlier hypotheses about peptide-dominated colloid self-assembly should be revived. Such macromolecular conglomerates presumably existed in a dynamic equilibrium between confluent growth in sessile films and microspheres detached in turbulent suspension. The first organic syntheses may have been driven by mineral-assisted photoactivation at terrestrial geothermal fields, allowing photo-dependent heterotrophic origins of life. Inherently endowed with rudimentary catalyst activities, mineral-associated organic microstructures can have evolved adaptively toward cooperative 'protolife' communities, in which 'protoplasmic continuity' was maintained throughout a graded series of 'proto-biofilms', 'protoorganisms' and 'protocells' toward modern life. The proneness of organic microspheres to merge back into the bulk of sessile films by spontaneous fusion can have made large populations promiscuous from the beginning, which was important for the speed of collective evolution early on. In this protein-centered scenario, the emergent coevolution of uncoded peptides, metabolic cofactors and oligoribonucleotides was primarily optimized for system-supporting catalytic capabilities arising from nonribosomal peptide synthesis and nonreplicative ribonucleotide polymerization, which in turn incorporated other reactive micromolecular organics as vitamins and cofactors into composite macromolecular colloid films and microspheres. Template-dependent replication and gene-encoded protein synthesis emerged as secondary means for further optimization of overall efficieny later on. Eventually, Darwinian speciation of cell-like lineages commenced after minimal gene sets had been bundled in transmissible genomes from multigenomic protoorganisms.
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Affiliation(s)
- Richard Egel
- Department of Biology, University of Copenhagen Biocenter, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark,
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Aizumi S, Shirao M, Yamamuro Y, Koizumi Y, Ono M, Furue H. Fabrication of Liquid Crystal Cell with Phase Separated Composite Organic Film. J PHOTOPOLYM SCI TEC 2013. [DOI: 10.2494/photopolymer.26.387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lu L, Sergan V, Bos PJ. Mechanism of electric-field-induced segregation of additives in a liquid-crystal host. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:051706. [PMID: 23214804 DOI: 10.1103/physreve.86.051706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/03/2012] [Indexed: 06/01/2023]
Abstract
The mechanism for electric-field-induced segregation of additives, containing a polar group, in a host liquid crystal is proposed. It is shown that the polarity of an applied dc electric field, or the frequency of an ac electric field, strongly influences the segregation of reactive monomers containing an ester group. An explanation of this result is offered based on the association of dissolved ions with polar groups of the reactive monomers. This association is considered to cause these types of additives to drift to the cell surface in the presence of an external electric field. The described mechanism can be applied to the segregation of a broad range of additives in a liquid-crystal host.
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Affiliation(s)
- Lu Lu
- Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
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Ho CY, Lin FH, Tao YT, Lee JY. Improvement in device performance from a mixture of a liquid crystal and photosensitive acrylic prepolymer with the photoinduced vertical alignment method. Sci Technol Adv Mater 2011; 12:065002. [PMID: 27877462 PMCID: PMC5090677 DOI: 10.1088/1468-6996/12/6/065002] [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: 08/25/2011] [Revised: 12/02/2011] [Accepted: 10/24/2011] [Indexed: 06/06/2023]
Abstract
In a multicomponent nematic liquid crystal (NLC) mixture of a liquid crystal (negative-type NLC) and a photosensitive acrylic prepolymer, photopolymerization upon UV irradiation induces the separation of the LC and photosensitive acrylic prepolymer layers, thereby leading to a vertical arrangement of LC molecules. In this study, we propose a simple vertical alignment method for LC molecules, by adding a chiral smectic A (SmA∗) liquid crystal having homeotropic texture characteristics to an NLC mixture solution. Measurements of electro-optical properties revealed that the addition of the SmA∗ LC not only strengthened the anchoring force of the copolymer alignment film surface, but also significantly enhanced the contrast ratio (∼73%), response time and grayscale switching performance of the device.
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Affiliation(s)
- Czung-Yu Ho
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Fa-Hsin Lin
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Yu-Tai Tao
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Jiunn-Yih Lee
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
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Bae KS, Cha U, Lee YJ, Moon YK, Choi HC, Kim JH, Yu CJ. Single pixel transmissive and reflective liquid crystal display using broadband cholesteric liquid crystal film. Opt Express 2011; 19:8291-8296. [PMID: 21643079 DOI: 10.1364/oe.19.008291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We propose a single mode transflective liquid crystal display (LCD) which is operated as the transmissive and reflective modes in a single pixel without dividing into sub-pixels. The single pixel transflective LCD was composed of the cross-polarized nematic LCD as a light modulator and the broadband cholesteric liquid crystal film (BCLCF) as a half mirror. The BCLCF, simply prepared by the exposure of ultraviolet light to the mixture of the nematic LC and the reactive mesogen with chirality, selectively reflects a certain circular polarization but transmits the orthogonal circular polarization in entire visible light. The electro-optical properties in both transmissive and reflective modes coincide with each other.
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Affiliation(s)
- Kwang-Soo Bae
- Department of Information Display Engineering, Hanyang University, Seoul, Korea
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Ho CY, Tsai PS, Lin HG, Li FC, Lin FH, Lee JY. Electro-optical characteristics in phase separated liquid crystal/photo-curable acrylic monomer mixture system. POLYM ADVAN TECHNOL 2011. [DOI: 10.1002/pat.1870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Marinov YG, Hadjichristov GB, Petrov AG. Single-layered microscale linear-gradient PDLC material for electro-optics. Cryst Res Technol 2009. [DOI: 10.1002/crat.200900147] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Fuh AYG, Chen CC, Liu CK, Cheng KT. Polarizer-free, electrically switchable and optically rewritable displays based on dye-doped polymer-dispersed liquid crystals. Opt Express 2009; 17:7088-7094. [PMID: 19399084 DOI: 10.1364/oe.17.007088] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This work demonstrates the feasibility of a polarizer-free, electrically switchable and optically rewritable display based on dye-doped polymer-dispersed liquid crystals (DD-PDLCs). Experimental results indicate that the doped dyes are homeotropically adsorbed onto the polymer film when an appropriate AC voltage is applied during patterning. The adsorbed dyes in the illuminated region then align the liquid crystals homeotropically, and produce a transparent pattern in the scattering background without any polarizer. Notably, the adsorbed dyes can be erased and readsorbed using thermal and optical treatments, respectively. The switching time of the fabricated display is of the order of milliseconds, and the contrast ratio is approximately 30.
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Affiliation(s)
- Andy Ying-Guey Fuh
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
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Benmouna R, Benyoucef B. Thermophysical and thermomechanical properties of Norland Optical Adhesives and liquid crystal composites. J Appl Polym Sci 2008. [DOI: 10.1002/app.28039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Marino A, Vita F, Tkachenko V, Caputo R, Umeton C, Veltri A, Abbate G. Dynamical behaviour of holographic gratings with a nematic film--Polymer slice sequence structure. Eur Phys J E Soft Matter 2004; 15:47-52. [PMID: 15372310 DOI: 10.1140/epje/i2004-10035-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have studied the dynamical response of a new kind of holographic grating to a pulsed electric field. The structure, named POLICRYPS, consists of a sequence of homogeneous polymer slices separated by liquid-crystal films. We have found that both the rise and fall response times depend on the pulse duration and amplitude of the applied electric field. We propose a phenomenological explanation for this behaviour, outlining the possibility of getting response times of the order of 100 micros by properly choosing the pulse shape. Results are very interesting for developments in which POLICRYPS gratings could be proposed as basic elements in photonic devices for telecom applications, and induce to a deeper analysis of the microscopic interaction between liquid crystal and polymer interfaces in these samples.
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Affiliation(s)
- A Marino
- INFM Unitá di Napoli, Dipartimento di Scienze Fisiche, Universitá di Napoli Federico II, Via Cinthia, M. S. Angelo 80126, Naples, Italy
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15
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Abstract
Data visualization plays a crucial role in our society, as illustrated by the many displays that surround us. In the future, displays may become even more pervasive, ranging from individually addressable image-rendering wall hangings to data displays integrated in clothes. Liquid-crystal displays (LCDs) provide most of the flat-panel displays currently used. To keep pace with the ever-increasing possibilities afforded by developments in information technology, we need to develop manufacturing processes that will make LCDs cheaper and larger, with more freedom in design. Existing batch processes for making and filling LCD cells are relatively expensive, with size and shape limitations. Here we report a cost-effective, single-substrate technique in which a coated film is transformed into a polymer-covered liquid-crystal layer. This approach is based on photo-enforced stratification: a two-step photopolymerization-induced phase separation of a liquid-crystal blend and a polymer precursor. The process leads to the formation of micrometre-sized containers filled with a switchable liquid-crystal phase. In this way, displays can be produced on a variety of substrates using current coating technology. The developed process may be an important step towards new technologies such as 'display-on-anything' and 'paintable displays'.
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Affiliation(s)
- Roel Penterman
- Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands
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Roussel F, Maschke U, Buisine JM, Coqueret X, Benmouna M. Phase diagrams of monomer and uv-cured difunctional-acrylate-nematic-liquid-crystal systems. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 65:011706. [PMID: 11800706 DOI: 10.1103/physreve.65.011706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2001] [Revised: 08/03/2001] [Indexed: 05/23/2023]
Abstract
This paper deals with the thermal properties of systems made of the difunctional monomer 1,6-hexanedioldiacrylate (HDDA) and the low-molecular-weight liquid crystal E7. Experimental phase diagrams of uv-cured and uncured solutions of HDDA/E7 systems are established with a polarized optical microscope and a differential scanning calorimeter and the data analyzed within a theoretical formalism that combines the Flory-Huggins model of isotropic mixing and the Maier-Saupe model of nematic order. Ultraviolet-curing samples with a difunctional monomer such as HDDA leads to a crosslinked polymer network and consequently an elastic contribution to the free energy is introduced according to the Flory-Rehner theory of rubber elasticity. The amount of liquid crystal segregated is evaluated to assess the efficiency of the phase separation mechanism.
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Affiliation(s)
- Frédérick Roussel
- Laboratoire de Thermophysique de la Matière Condensée, Equipe de l'UPRESA CNRS 8024, Université du Littoral Côte d'Opale, MREID, F-59140 Dunkerque, France.
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