January 26, 1996. Copyright, 1996, Graphic News. All rights reserved

BRIGHTER SCREENS BECKON FOR HOME ENTERTAINMENT
By Nicholas Booth, Science Editor

LONDON, January 26, Graphic News- The age of cinema screens in the home may soon be upon us, claims a British company which is developing a revolutionary video projection system. It may also sound the death knell for the traditional cathode ray TV screen as well as introducing many other revolutionary innovations in the entertainment field. BritainÕs Rank Brimar has spent some £20 million to develop its Super-High-Brightness Digital Video Projector which will go on sale later this year for around £120,000 and will be portable. 

Existing projection systems are limited in the brightness of the images that they can project. Rank Brimar has increased this by use of half a million mirrors each smaller than the width of a human hair, embedded upon a microchip developed in the United States by Texas Instruments. The myriad mirrors within the Digital Micromirror Device (DMD) are suspended like tiny, exquisite seesaws and reflect light in different directions under the control of a memory cell. Each DMD is just 1.6 centimetres wide and is covered by more than 500,000 aluminium mirrors, each of which covers one pixel, 1.6 microns across. 

The tiny mirrors are suspended on aluminium-alloy hinges and effectively switch on or off depending on the light shining upon them. A high-powered light source focuses on three DMDs, each one responding to a separate primary colour Š red, green or blue. Special light-splitting optics are used to project the image by use of filters, and after passing through the DMD, the image is then accurately recombined through a single lens to form a stable image on a screen. 

The technology promises a breakthrough for the TV industry. Existing TV systems are limited: cathode ray tubes are cumbersome whereas liquid crystal displays are expensive and difficult to mass produce. Because the mirrors are so light, the screens could be portable and could soon be used in pop concerts, theme parks, business conferences and even political conventions. The company has developed a demonstration prototype which projects on to a 100 square foot screen. Unlike most video projection systems, the image produced is bright, no light falls off at its edges, nor is there any flickering or lack of contrast. 

SOURCES: Rank Brimar, Texas Instruments