Development of Holographic Color Display

我们开发了一种分时全息彩色显示系统，该系统具有高分辨率反射LCD面板和低功率RGB激光器。重建的高分辨率图像具有较大的色域和良好的色彩表现。我们还利用多通道液晶调制器扩大了全息显示器的可视区域或视野。采用6通道LCD调制器，将彩色图像的视区角度或视场角度放大约20度。其次，讨论了全息显示中三维图像的质量劣化问题。数值模拟结果表明，液晶面板的非线性特性和调幅引起的相移对全息显示重建的三维图像质量有显著影响。在实验中提出了提高重建图像质量的新方法。为了同时记录RGB全息图，提出了一种利用反射液晶面板进行移相的方法。利用相移全息技术，从记录的直线全息图中获得了精细的复幅RGB全息图，并通过复幅全息图对实际物体的高质量彩色图像进行了数值重建。我们还开发了一种用于彩色三维图像复振幅全息图瞬时记录的单镜头数字全息新技术。在此基础上，提出了一种新的全息图信息约简方法，使具有运动视差的三维图像在宽视域内显示。观察者可以通过两只眼睛观察一对重叠的立体图像来感知图像的运动视差。图像的视觉深度可以通过观看立体部分图像来感知。

We have developed a time-sharing holographic color display system with a high-resolution reflective LCD panel and with low-power RGB lasers. Reconstructed high-resolution images have large color gamut and exhibit fine color expression. We have also enlarged the viewing zone or the visual field of the holographic display using a multi-channel LCD modulator. The viewing zone angle or the visual field angle of color images is enlarged up to about 20 degrees by adopting a 6-channel LCD modulator. Next, quality deterioration of 3-D images in the holographic display has been discussed. Results of the numerical simulation showed that the nonlinear characteristics of a LCD panel and the phase shift due to the amplitude modulation have significant influences upon the quality of 3-D images reconstructed from the holographic display. New methods were described for improving the quality of reconstructed images in the experiment.A phase-shifting method using the reflective LCD panel has been proposed in order to record RGB holograms simultaneously. Fine complex-amplitude RGB holograms were obtained from recorded in-line holograms by the phase-shifting holography, and high-quality color images of the practical object were numerically reconstructed from the complex-amplitude holograms. We have also developed a new technology of one-shot digital holography for instantaneous recording of the complex-amplitude hologram for color 3-D images. Next, new methods for information reduction in hologram have been proposed to display the 3D image with motion parallax in the wide viewing zone. Observer can perceive motion parallax of the image by viewing a pair of overlapped stereoscopic images with both eyes. The visual depth of the image can be perceived by viewing stereoscopic partial images.