Proceedings Article | 17 April 1998
KEYWORDS: Projection systems, Imaging systems, Lamps, Digital micromirror devices, Televisions, Reflectivity, Image segmentation, CRTs, LCDs, Polarization
The explosive growth in sales of projection displays began only five years ago with the commercial introduction of microdisplays, small electronic imagers. The microdisplay packs the imaging capability of a television or computer monitor into an integrated circuit chip and is a disruptive technology, representing a breakthrough in performance and price when compared with alternative direct view displays. Microdisplay based projectors for conference rooms have already had a dramatic impact on the presentation market with unit volume approaching 500,000 systems and factory revenues exceeding $2 billion in 1997. But the revolution has just begun. New front projection systems with much higher light throughput will fuel the growth of systems designed for board rooms and large venues. New small, light weight, portable projectors, weighing less than 10 pounds, targeted at road warriors, will open up yet another segment of the presentations market. During the next few years, further improvements in the performance and pricing of microdisplays, coupled with higher performing lamps, optics, and electronics will enable microdisplay based projectors to penetrate the mainstream television and monitor markets. Microdisplay based rear projection displays will compete head to head with CRT based displays for big screen, high definition dominance. Higher definition and cheaper microdisplays are a key requirement for the expansion of projection display applications. First generation technology microdisplays are based on two competing technologies: The first, a transmissive imager, combines an active matrix integrated circuit backplane made with poly-silicon on quartz technology with a twisted nematic liquid crystal front plane (p-Si/TN); the second, a reflective imager, uses a crystalline silicon backplane circuit to activate microelectromechanical mirrors (Texas Instruments digital micromirror device, the DMDTM).'6 Both of the established competitive microdisplay designs are challenged when it comes to delivering a higher definition image at a lower price.24 Price reduction will flow primarily from reducing the size of the microdisplay imager. But size and cost reduction necessitate smaller pixel sizes, especially for high definition imagers, and current costs for both the p-Si/TN and DMD devices limit their use to systems with selling prices of more than $3,500.00. A number of developers are introducing a second generation of microdisplays that use CMOS active matrix backplanes in combination with reflective liquid crystal front planes (c-SiJRLCD). Such devices hold the promise of further breakthroughs in performance and price.14744 Microdisplays of about the same size and cost as the established devices hold the promise of higher definition displays for both the presentation market as well as high definition television. Smaller and cheaper cSi/RLCD high definition microdisplays promise to open up new markets for rear projection desktop monitors and PCTVs.'2 To understand the impact that the continued evolution of microdisplay technology will have on the performance and price of projection displays, the competing technologies will first be compared and evaluated in conjunction with the performance of other critical components of a projection system. Next, the market requirements for displays in each market segment will be compared. In the final section, a forecast for the growth of microdisplay based projectors will be developed
