OL3.JUL–SID–pm
Prototype promises lower-cost, higher-performance AMLCDs
As a step toward bringing down the cost of active-matrix LCDs (AMLCDs)
while at the same time improving their performance, Kopin Corp. (Taunton,
MA) announced the results of its prototype transmissive 640 x 480-pixel
AMLCD formed from single-crystal silicon (x-Si). The results were
presented at the recent Society for Information Display (SID) Seminar and
Exhibition in Seattle, WA. If all goes well, the company hopes to have a
product available by the end of the year. With a resolution of 500
lines/in., the prototype, dubbed Smart Slide, has approximately 300,000
transistors in an area of 1.5 in.2 and integrates the
control electronics in the display. The display has a bandwidth of 50 MHz
and requires only 11 pins to drive it. Over a period of 8 months, Kopin
leveraged its IC-wafer-engineering expertise to bring the x-Si-based
display technology to fruition. The company's approach involves
fabricating integrated circuitry on thin-film, single-crystal silicon, and
then transferring a transparent, 0.5-micron-thick layer of integrated
circuitry to the glass (see diagram). Kopin gave this layer the name Smart
Slide because it contains intelligence and looks somewhat like a
photographic slide. Unlike amorphous silicon (a-Si) or polycrystalline
silicon (poly-Si), the two technologies currently being used, x-Si has the
high electron mobility required for complex circuitry. Till now, x-Si was
used for the column and row driver and buffer circuitry on the display
periphery. With the transparency achieved in Kopin's process, the complex
circuitry can be placed directly on the display to reduce overall display
size and improve response time. Key to this whole process is the use of
standard IC-manufacturing techniques, and it is on this that Dr. John Fan,
president of Kopin, is pinning his hopes. According to Fan, Kopin, like
many U.S.-based companies, lacks many of the resources needed for a
successful launch into the AMLCD market in face of the 10 years of
experience and multibillion-dollar investments already made by
established, mainly Japan-based, display manufacturers. A manufacturing
facility alone would cost upward of $300 million. Using established IC
houses avoids this initial investment while at the same time it improves
reliability, reduces cost, and speeds time to market. However, with market
figures for AMLCDs estimated at upwards of $4.4 billion by 1999, according
to Stanford Resources (San Jose, CA), x-Si will meet plenty of
competition. For the foreseeable future, the penetration of x-Si displays
in the lucrative laptop market will be limited for two reasons. First,
conventional a-Si and, more recently, poly-Si displays are already firmly
entrenched. Second, the cost of the IC-wafer-manufacturing process used
for Kopin's x-Si display becomes prohibitive for displays larger than 5
in. However, Kopin hopes to capitalize on the x-Si's high-resolution
potential to reach applications in projection systems, virtual reality, and
rear-projection monitors. This resolution goes as high as 2,000 x 2,000
pixels for a display the size of a 35-mm slide. Already, Kopin has
Advanced Research Projects Agency support in the form of $9.2 million for
a design involving a 1,280 x 1,024-pixel display for head-mounted
applications. For more information, contact Jack Salerno of Kopin Corp.at
508-824-6696, or . –Patrick Mannion
CAPTION:
Using its experience in wafer engineering, Kopin has managed to remove a
0.5-micron film of x-Si material, with intelligent drive circuitry intact,
and place it on the glass using adhesive.
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