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Ko-Wei Chien

Publications and source records attributed to Ko-Wei Chien.

3 recordsLinked to original sources

Time-multiplexed three-dimensional displays based on directional backlights with fast-switching liquid-crystal displays.

An autostereoscopic display using a directional backlight with a fast-switching liquid-crystal (LC) display was designed and fabricated to obtain a better perception of 3D images by enhanced resolution and brightness. A grooved light guide in combination with an asymmetric focusing foil was utilized to redirect the emitting cones of light to the left and right eyes, respectively. By designing the groove structures of the focusing foil with rotation from -1.5 degrees to 1.5 degrees in the gradient and having the pitch ratio of the grooved light guide to the focusing foil of less than 3, the boundary angle then shifts from normal viewing and the moiré phenomenon can be suppressed. Cross talk of less than 6% and a LC response time of faster than 7.1 ms further improve the stereoscopic image perception. Additionally, 2D-3D compatibility is provided.

Journal Article↗

Polarized backlight based on selective total internal reflection at microgrooves.

A polarized backlight for LCD illumination is designed and fabricated in which s-polarized light is extracted owing to selective total internal reflection at microstructures in the anisotropic layer. From the measurement, the contrast ratio in normal viewing direction can be as high as 64. Luminous uniformity of higher than 80% is achieved for polarized backlights. Furthermore, 1.6 gain in efficiency is obtained aiming for high-efficiency LCD illumination.

Journal Article↗

Design and fabrication of an integrated polarized light guide for liquid-crystal-display illumination.

An integrated polarized light guide was designed and fabricated for use as a liquid-crystal backlight with emphasis on uniformity of the light and conversion of p-polarized to s-polarized light. Two different micro-optical structures were fabricated both on the top and the bottom surfaces of the light guide. On the top surface, a subwavelength grating separates s-polarized and p-polarized light to achieve a polarization-conversion efficiency of 69%. A 1.7 gain factor of polarization efficiency was obtained to increase the utility of light for liquid-crystal illumination.

Journal Article↗