Abstract. When a directional backlight to each eye alternates synchronously with the alternation of left-eye and right-eye images on the display panel, the viewer can see a stereoscopic image without wearing special goggles. One way to realize a directional backlight is to place a convex lens array in front of dot matrix light sources to generate collimated light. To implement this method, however, defocusing and field curvature of the lens should be taken into account. The viewing zone of an autostereoscopic display with a directional backlight using a convex lens array is analyzed based on optical simulations. IntroductionTime-division multiplexing is one of the major methods to attain a stereoscopic display. With the advancement of liquid crystal display (LCD) technologies, LCD panels that can attain a short response time (120 Hz or faster) have been developed, which has enabled commercialization of threedimensional (3-D) LCD TV sets based on the time-division multiplexing coupled with shutter glasses.LCD panels operating at high refresh rates can also be applied to autostereoscopic displays with high resolution. Most autostereoscopic displays developed so far are based either on parallax barrier technology or on lenticular lens technology. Though multiple display pixels under a single aperture or lens can create multiple viewing zones, the cost to this is a significant loss in resolution. The time-division multiplexing has enabled the presentation of a stereoscopic image whose resolution is the same as that of the display panel.One of the simplest ways to realize high resolution autostereoscopy with time-division multiplexing is to use an active parallax barrier.1-3 Fixed parallax barrier with two viewpoints reduces the resolution of the image by half. By alternating the position of the parallax barrier and the image on the display panel synchronously at a high refresh rate, a full resolution 3-D image can be delivered to the

SUMMARYWe realize homogenous luminance of the directional backlight for the time-division multiplexing autostereoscopic display using a convex lens array with the elemental lenses whose phase of placement in each row differs from one another. The validity of the proposed optical design is confirmed by a prototype system.

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This paper proposes two methods to expand the viewing zone of the autostereoscopic display with a directional backlight composed of a linear Fresnel lens array and a dot matrix light source. The viewing zones free from crosstalk in the proposed methods are analyzed based on optical simulations.