Achromatic doublet electrowetting prism array for beam steering device in foveated display

Cooperative correction method for distortion and dispersion of deflected field of view in Risley-prism bionic-human-eye imaging systems

The Risley-prism imaging system (RPIS) is a powerful way to achieve bionic human eye imaging with great advantages on large field of view (FOV) and variable resolution imaging owing to the autonomous controlled deflection of light. But the imaging dispersion originating from nonlinear and uneven light deflection results in limited imaging wavelength that seriously hinders its application. The existing solutions for imaging dispersion mainly rely on the hardware, which generally has bulky structure and limited improvement on image. Besides, the existing image evaluation methods for dispersion are not suitable for RPIS due to inhomogeneous dispersion. Herein, this paper systematically analyzes the mechanism and characteristics of dispersion in the RPIS, and proposes a cooperative correction method for image distortion and dispersion of multiple-color imaging, achieving the elimination of distortion and dispersion simultaneously without changing the optical structure. A dispersion evaluation index based on Pearson's correlation coefficient (PCC) is also established, and the objectivity and validity of the index are proved by experiments. Furthermore, a kind of compact RPIS based on an RGB camera is built, and both indoor and outdoor experiments are conducted. The experimental results demonstrate that proposed algorithm has strong universality and robustness for various scenes and targets.

Perceptually-guided Dual-mode Virtual Reality System For Motion-adaptive Display

An ideal Virtual reality (VR) device should simultaneously provide retina-level resolution, wide field-of-view (FOV), and high refresh rate display, thereby bringing users into a deeply immersive virtual world. However, directly providing such high-quality display poses great challenges for display panel fabrication, real-time rendering, and data transfer. To address this issue, we introduce a dual-mode virtual reality system based on the spatio-temporal perception characteristics of human vision. The proposed VR system has a novel optical architecture. It can switch display modes according to the user's perceptual requirements for different display scenes to adaptively adjust the display spatial and temporal resolution based on a given display budget, thus providing users with the optimal visual perception quality. In this work, a complete design pipeline for the dual-mode VR optical system is proposed, and a bench-top prototype is built with only off-the-shelf hardware and components to verify its capability. Compared to the conventional VR system, our proposed scheme is more efficient and flexible in utilizing the display budget, and this work is expected to facilitate the development of the VR device based on the human visual system.

Design and fabrication of a focus-tunable liquid cylindrical lens based on electrowetting

In this study, a focus-tunable liquid cylindrical lens based on electrowetting was designed and fabricated. The cylindrical cavity usually used in common electrowetting zoom spherical lenses was replaced by a 20 mm × 10 mm × 8 mm cuboid cavity, in which the interface of two liquids formed a toroid owing to the electrowetting effect. The proposed liquid cylindrical lens can serve as either a converging or diverging lens with the response time under 110 ms by changing the supplied voltage. The zoom lens we fabricated worked stably under 0-110 V voltage for a long time, guaranteeing that the focal length of the liquid cylindrical lens can range within (-∞, -148.36 mm) ∪ (697.21 mm, +∞). By combining the liquid lens that we designed with a simple fixed cylindrical lens, a cylindrical lens system with an arbitrary focal length suitable for various tasks in beam manipulation can be realized.

High-Precision Beam Angle Expander Based on Polymeric Liquid Crystal Polarization Lenses for LiDAR Applications

A novel beam steering angle expander is demonstrated by cascading two polymeric liquid crystal polarization lenses with different diopters. The lens module performs as a planar telescope, which has features such as a light weight, low cost, and high precision. The magnifier offers wide-angle, continuous steering when integrated with an active fine-angle beam steering device. The potential application for LiDAR is emphasized.