Landscape/Portrait Dual Mode Lens Type 3D Display Using a 2D Lens Array Ching-Tsun Chang, Wen-Lung Chen, Chih-Hung Shih, Wei-Ming Huang * AU Optronics Corporation, No. 1, Li-Hsin Rd. 2, Hsinchu Science Park, Hsinchu 30078, Taiwan, R.O.C. Abstract Traditionally, a lenticular lens array, which is a one-dimensionally periodic lens structure, is used in front of a image display, such as LCD or OLED, to achieve human 3D perception. Due to its one- dimensionally periodic property, most of this kind of 3D displays can show 3D in only one display orientation. In this paper, we utilize a 2D lens array instead to achieve human 3D perception in both landscape and portrait display orientation. The 2D lens array is fabricated using ink-jet printing (IJP) technology and the 3D function is demonstrated successfully. Author Keywords autostereoscopic; lenticular; barrier; ink-jet priting 1. Introduction 3D display technologies give people new and more impressive viewing experiences and are under increasing development. Among them, lenticular lens [1] and parallax barrier [2] are two major technologies used to achieve autostereoscopic displays. No matter which technology is used, they all provide 3D perception through binocular disparity, by which left eye sees only left eye image and right eye sees only right eye image through different viewing angle. Under this condition, human brain fuses these two images into 3D illusion. Figure.1 shows the binocular disparity and the possible types of disparity that produce different 3D depth. (a) (b) Figure 1. Illustration of binocular disparity (a) and different types of disparity (b). The parallax barrier achieves 3D by blocking the right-eye signal toward left eye and the left-eye signal toward right eye. It’s a relatively simple way and the fabrication of parallax barrier is compatible to LCD process. However, the parallax loses brightness due to the blocking of light (Figure 2 (a)). The lenticular lens doesn’t suffer the brightness loss as parallax barrier. The lenticular lens refracts the left-eye signal to the left eye and right-eye signal to the right eye (Figure 2 (b)). (a) (b) Figure 2. The principle of parallax barrier (a) and lenticular lens (b). Both the stripe parallax barrier and lenticular lens can provide 3D perception in one direction such as landscape viewing mode or portrait viewing mode. Because the blocking effect of parallax barrier and the lens convergence only happen in the direction perpendicular to stripe parallax barrier or lenticular lens. For LC barrier, landscape/portrait dual mode can be carried out by design orthogonal ITO electrode on top and bottom plate in one cell. However, lenticular lens can not do the same thing in one lenticular lens sheet due to its physical structure. To provide 3D effect in both landscape and portrait viewing mode, the lens convergence effect in both mode is necessary. The most straight-forward method is to use spherical lens with proper aperture geometry instead of cylindrical lens. This paper uses spherical lens 2D array with proper horizontal and vertical pitch. It is called 2D lens array in this paper. 2. 2D Lens Array Design As mentioned in previous section, we use 2D lens array to achieve landscape/portrait dual mode 3D viewing. In this section, we are going to explain the basic design parameter of 2D lens array. As shown in figure 3, the lens pitch should be properly design to ensure that people can see correct signals through each lens element at the desired viewing distance. Because average inter- pupil distance is about 65mm, we design the lens pitch based on this condition. Figure 3 take parallax barrier as an example, however, the pitch design is the same for both parallax barrier and lenticular lens. Without proper pitch design, observer cannot see 3D across whole display.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Landscape/Portrait Dual Mode Lens Type 3D Display Using a 2D Lens Array