Compaq Computer Corporation, Inc.

Duke University

Mehdi Zeinali

Richard M Knox

A polymer dispersed liquid crystal projection display is provided that has enhanced contrast. In the projection system using a polymer dispersed liquid crystal display (PDLC), polarized light is used as the light source onto the PDLC. The reflected light maintains its polarization, while the scattered light from the off pixels of the PDLC randomize the polarization. The polarized image is then passed through a polarizing filter which eliminates half of the scattered light, whereas practically all of the polarized image is passed onto the display source. In this way, the contrast between the on and off pixels is effectively doubled.

Contrast polymer dispersed liquid crystal projection display system

A projection apparatus provides a projection engine that supplies polarized light to a dielectric filter (or diffraction grating). The dielectric filter provides an array of pixels that each pass selected colors of light and reflect other colors. Each pixel is subpixelated (for example, red, green, and blue subpixels) so that a single subpixel passes a selected color (for example, red) and reflects the other colors (for example, green and blue). A digital micromirror device has an array of mirrors that correspond in number to the number of subpixels of the dielectric filter. Each of the mirrors provide 'on' and 'off' positions for selectively transmitting a desired color of light from the mirror to an image screen. The image screen receives light reflected by selected of the mirrors of the array of micromirrors when the selected mirrors are in the 'on' position. The micromirror device can be controlled with a computer, television, signal, video signal, or the like.

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Spring, TX, United States of America

Mehdi Zeinali