• Acta Photonica Sinica
  • Vol. 51, Issue 5, 0511001 (2022)
Zichao WEI, Yimin LOU*, Juanmei HU, and Fengmin WU
Author Affiliations
  • Key Laboratory of Optical Field Manipulation of Zhejiang Province,Department of Physics,Zhejiang Sci-Tech University,Hangzhou 310018,China
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    DOI: 10.3788/gzxb20225105.0511001 Cite this Article
    Zichao WEI, Yimin LOU, Juanmei HU, Fengmin WU. Partition and Time Division Multiplexing Retinal Projection Display Based on Human Visual Characteristics[J]. Acta Photonica Sinica, 2022, 51(5): 0511001 Copy Citation Text show less

    Abstract

    Recently, near-eye display technology has developed rapidly. Augmented reality, virtual reality, and other related products have begun to enter the field of mass consumption, bringing people a novel visual experience. However, while enjoying the visual feast, users have to endure traditional near-eye display technology defects, such as small angle of view, limited exit pupil area and resolution, easy to cause dizziness, and visual fatigue. To solve the above problems, researchers began to explore the application of holographic display, light field display, and retinal projection display technology to improve the visual effect of near-eye display and enhance the comfort of use. Among them, retinal projection display technology has attracted much attention because of its advantages of a simple solution, compact structure and easy integration.Retina projection display technology is based on the principle the of Maxwellian view. The human eyeretina is used as a display screen, and a clear image is projected directly on it to avoid image blur caused by eye focusing. Using this method can effectively alleviate the problem of visual fatigue caused by the conflict of vergence and accommodation, but it has the disadvantages of small exit pupil diameter and inability to provide correct depth information. To overcome the above shortcomings, a partition and time-division multiplexing 3D retinal projection display technology using the principle of Maxwellian view is proposed.According to the human visual characteristics, the virtual scene is divided into an edge background area and a central gaze area. Time-division multiplexing 3D retinal projection display technology is used for the central gaze area to display the image group on the DMD at high frequency. At the same time, the point light sources in the LED array are controlled to illuminate synchronously according to the same time sequence, and the image group refreshed by the DMD are views corresponding to each viewing angle. These views are matched with the viewing angles corresponding to the illumination angles of the point light sources to form multi-view images for time-division multiplexing projection. When the frequency of the time sequence is high enough, an observation window with dense viewpoints can be formed at the exit pupil by using the visual persistence effect of the human eye. The human eye can feel the effect of continuous superposition of multi-view images at the exit pupil position, realizing a true three-dimensional display with monocular focusing depth information, and increasing the exit pupil area. In the edge background area, a short-focus lens and a liquid crystal display device are used to obtain a larger edge viewing angle, and a half mirror is used as an optical combiner to fuse the image information of the central gaze area and the edge background area.It can be seen from the 3D effects of the central gaze area that the system realized a true 3D retinal projection display with monocular focusing depth information. Afterwards, to achieve an accurate depth display, we calibrated the actual depth position of the 3D images using the virtual depth value set in the computer. By calibration, the relationship between actual and virtual depths is obtained, so that more accurate depth images can be achieved. In further experiments, we verified the effect of the partition display: 3D retinal projection technology was used in the central gaze area to obtain a true three-dimensional display with monocular focusing and defocusing effects. The LCD and short focus eyepieces were used in the edge area to achieve a wide viewing angle display, and the center and edge images were well fused. The total viewing angle of the system is about 32°, which can cover the effective field of view of the human eye, including a viewing angle of about 7° in the foveated region. For edge areas, our system can also flexibly set the required depth of the background area by controlling the distance from the short focal lens to the LCD. This system can effectively alleviate the problem of visual fatigue. It also reduces the amount of data required for 3D rendering, while improving the visual experience of the near-eye display system, and also has good application prospects.
    Zichao WEI, Yimin LOU, Juanmei HU, Fengmin WU. Partition and Time Division Multiplexing Retinal Projection Display Based on Human Visual Characteristics[J]. Acta Photonica Sinica, 2022, 51(5): 0511001
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