A novel stereoscopic/3D desktop monitor has been developed that combines the output of two active matrix LCDs (AMLCDs) into a stereo image through use of a unique beamsplitter design. This approach, called the StereoMirror, creates a stereo/3D monitor that retains the full resolution, response time and chromaticity of the component displays. The resultant flicker-free image, when viewed with passive polarizing glasses, provides an unprecedented level of viewing comfort in stereo. The monitor also is bright enough to use in normal office lighting. The display has excellent optical isolation of the two stereo channels and a wide viewing angle suitable for multi-viewer use. This paper describes the architecture of the system and the principal of conservation of polarization that results in the full-definition stereo image. Optical performance results are also described. Practical considerations will be discussed, including system interface requirements, conversion between stereo/3D and monoscopic viewing and comparison to other stereo display approaches. The higher level of performance provided by the StereoMirror allows for stereo viewing to be viable in new imaging markets as well as permitting a more effective use of stereo in existing markets. These applications are discussed.
During the past decade the performance and price of projection systems based on microdisplays have demonstrated dramatic improvements. Ultraportable front projection systems can deliver nearly 1000 lumens of light at XGA definition and street prices of such systems are rapidly falling to $2,000. The market leading low priced presentation projectors use two alternative microdisplay technologies: transmissive liquid crystal with a high temperature poly-silicon on quartz backplane (HT p-Si) or the reflective digital micromirror device (DMD1' , made with CMOS. These incumbent microdisplay technologies are now being challenged by several new approaches, including reflective liquid crystal on a silicon backplane (LCOS) and transmissive liquid crystal with a low temperature poly silicon on glass backplane (LT p-Si). In addition to new microdisplay technologies, developers have been demonstrating new single imager projector architectures that have the promise of leading to even lower systems costs. While the color field sequential DMD system and the larger 3 to 6 inch spatial color transmissive liquid crystal with an amorphous silicon on glass backplane (a-Si) are the only commercial single imager designs, single microdisplay projectors have been demonstrated using color field sequential LCOS1, spatial holographic microlens LCOS2, and a spatial system than employs color scrolling and a LCOS imager3. While the presentations market continues to offer a major growth opportunity for the projector developers, the potential use of microdisplay technology in the television market offers, at minimum, an incremental market opportunity, and at maximum, a huge potential additional market. But for the home market to amount to much, the microdisplay based televisions will have to offer much better value to consumers than the current rear projection CRT TVs. Otherwise, rear projection televisions will remain a North American niche market with demand of 1 million units per year and modest growth. Unless the new microdisplay televisions offer better value, their makers will be fighting for a share of a modest market against deeply entrenched competitors What does better value mean? Published market research as well at several studies completed by McLaughlin Consulting Group4 (MCG) indicate a hierarchy of consumer preferences for NTSC televisions. Not surprisingly, for the American market two characteristics lead all consumer preference lists: price and size. As shown in Table 1 ,secondary preferences include brightness, contrast, image quality, tuning options, cabinet depth, weight, and sound system. Well down the list are features such as power and safety.
Projection lamps and light sources are on the critical path to the widespread application of projection systems. Not only are the projection lamps the weak link in determining system lifetime, but the purchase price of the lamp and power supply could limit the growth of projection technology in system that sell for less than 3,000 dollars.
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