Jeffrey A. Shimizu

40.1: Invited Paper: Scrolling Color LCOS for HDTV Rear Projection

We report on advancements for a single-panel Liquid Crystal On Silicon (LCOS) display based on the Philips scrolling-color architecture. Performance and cost advantages make this system ideal for High Definition Television (HDTV). We discuss aspects of a 64″ rear projection display showing a 1280×720 image.

Design aspects of a scrolling color LCoS display

Abstract The Philips scrolling color liquid crystal on silicon (LCoS) architecture is a very attractive approach towards affordable large area displays. The color sequential nature coupled with high resolution brings demands on speed and bandwidth. Design requirements and solutions tailored to address scrolling color LCoS demands are presented. We have implemented high quality displays based on silicon backplanes employing a mixed digital–analog construction, high speed FPGA based drive electronics, a thin nematic liquid crystal cell, and a scanning stripe optical engine. Despite challenging demands we have found many opportunities to exploit available technologies in our system designs.

Single-panel reflective LCD projector

We have constructed a high resolution projection display with a single reflective LCD panel. Reflective technology based on standard silicon CMOS processing has emerged as a favorable direction for projection displays. Advantages include low investment and fabrication costs, high resolution capability, and high aperture ratio. As a move towards lower cost and high performance, we have applied reflective technology to a single panel projection display. The pixel array is SXGA and is fabricated in a process with both 5 Volt logic and 15 Volt structures. A thin 1 micron liquid crystal cell is formed over the array. A fast on time of 0.2 ms is attained with a nematic LC effect. System architecture is based upon a scrolling color illumination system wherein three color bands are present on the panel at all times. This arrangement avoids the 2/3 light loss in spectral efficiency present in a more conventional color wheel system. The system demonstrates that color sequential projection displays are feasible with LCD devices. And this direction holds great promise in a wide variety of applications including consumer HDTV displays.

Rear projection screens for light-valve projection systems

Rear projection screens of light valve systems will be significantly different from existing screens used in consumer CRT rear projection sets. Artifacts such as speckle and more stringent requirements for resolution will direct the development of light valve screens. In this paper, we will give a mathematical analysis of the origin of speckle and will describe systems that were developed to measure the speckle contrast and the resolution of the screen in the presence of speckle. We will describe new screen designs that reduce the speckle contrast to an acceptable level while maintaining specifications for gain and resolution.

64.1: Invited Paper: A Light Guide Engine for Single‐Panel LCoS

Using light guide components we have developed a new scrolling-color engine for single panel LCoS projection. Light guides allow for lossless delivery of light leading to a simpler and more compact system. Engine design and construction based on a single 0.87-inch diagonal LCoS panel is described.

A single-panel LCoS engine based on light guides

— By using light-guide components, a new scrolling-color engine for single-panel LCoS projection has been developed. Light guides allow for loss-less delivery of light leading to a simpler and more-compact system. Engine design and construction based on a single 0.88-in.-diagonal LCoS panel is described. Separate results with a multilayer optical film Cartesian PBS show that a significant improvement in system efficiency is possible.

Contrast improvements for scrolling-color LCoS

A scrolling-color LCoS (liquid-crystal-on-silicon) display must exhibit both fast speed and high contrast. These requirements drive design choices for the liquid crystal and optics of the image kernel. The input director was aligned to the incoming polarization and a compensated 45TN0 effect was choosen. Contrast demands place tight requirements on interfacial reflections. A wire-grid PBS can achieve high contrast and can simplify the system construction. With attention to the above, we report a sequential contrast of 800:1 at the viewing screen. With a 90TN0 effect, the contrast can be increased even further, but with some penalty in light efficiency. With this effect, sequential contrast of 2000:1 was measured.