Generation of 3D Image on Optically Rewritable Liquid Crystal Display Lu Wang, Jiatong Sun, Xiaoqian Wang, Abhishek Srivastava, Vladimir Chigrinov Center for Display Research, Department of Electronic and Computer Engineering Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Abstract In this paper, the method for generating 3D image on Optically Rewritable Electronic Paper (ORW E-paper) is presented. By making use of the photo-alignment, the two same but overlapping images (“Hong Kong”) are optically written on the cell with a slight position shift and different alignment configuration. Then a quarter- wave plate is put onto the cell to transfer the light into left and right circular polarization for each image. The 3D image can be created on only one cell without double cell configuration. The preparation is also easy with only two steps. Results show that the images seen by the two eyes are the same but with position difference, which indicates a real 3D effect. Keywords: Optically Rewritable Electronic Paper, Photo- alignment, 3D image; 1. Introduction The Electronic paper which can be printed by light is proposed in [1]. The bottom layer can be coated with alignment material like Polyimide 3744 which will not be affected by the light. The upper layer is coated with photo-alignment material SD1 whose aligning direction is perpendicular to the polarization of the light exposed on it. When the cell is filled with liquid crystal like 5CB or E7, the grayscale image can be generated on the cell by exposing different areas with different polarized light. The working principle is also illustrated in Figure 1. It has the advantage of zero power consumption in normal display. Fig.1 Working Principle of the ORW E-paper In the ref[1], the generation of 3D image is also proposed. However it needs double cell to define the 3D images and also the two same images cannot be overlapped, which will not generate a real 3D effect. In this paper, we propose a method to generate the two overlapping and same images with position difference on one cell, which saves the cost and achieves a real 3D effect. 2. Methodology In Figure 2, it shows the cell fabrication procedure. The upper layer is coated with SD1 and the bottom layer is coated with PI 3744. The 10μm gap cell is filled with 5CB. After fabrication, the cell is exposed with the light polarized perpendicular to the aligning direction of the bottom PI, so the cell will be homogeneously aligned with no twist. Fig. 2 Cell Fabrication Procedure The two same images are exposed on the cell by two steps. Three regions will be created on the cell. Region 1 is the area which belongs to the left eye and doesn’t belong to the right eye. Region 2 is the area which belongs to both of the eyes, say, the overlapping part of the two same images. Region 3 is the area which belongs to the right eye and doesn’t belong to the left eye. Figure 3 shows the three regions exposed by two steps with LED 450 nm blue light of 80mW/cm2. In the first step, the polarizer is fixed on top of the cell with 45 degree tilt right with respect to the aligning direction on the bottom layer. The light will pass the polarizer and the image mask consecutively to expose the cell. In the second step, the polarizer is fixed with 45 degree tilt left with respect to the aligning direction on the bottom layer. A line by line mask with 50 μm width is also put below the polarizer and on top of the cell. So only every other line will be exposed in the second step and the other part’s aligning direction will stay unchanged. Also the image mask in the second step should shift a little to create the difference. The light will pass the polarizer, the line by line mask and the image mask consecutively to expose the cell. Fig. 3 Two steps to prepare the cell P-24 / L. Wang SID 2012 DIGEST • 1139 ISSN 0097-966X/12/4303-1139-$1.00 © 2012 SID