Date Visited: October 5, 1991
Report Author: A. Firester
Mr. Takei graciously acted as our escort on our trip to and from Seiko. We arrived at about 10:00 a.m. and left about 3:45 p.m.. The meeting was hosted by Mr. Kono. An outline of our meeting follows.
Seiko-Epson is a privately held company in the Seiko Group. The four companies in the Seiko Group are shown in Table Seiko.1 with their principal products.
Company statistics provided by Mr. Koyama are as follows:
Head office -
Annual sales -
Large-size module '91 projected market
Total: 100,000 million yen
Although Seiko-Epson was first to market with a silicon chip wrist TV in 1982 and a p-Si pocket TV in 1984, they discontinued their p-Si pocket TV products in 1986 and switched to MIM as the active matrix technology for their pocket TVs. Their current plans are to pursue p-Si active matrix for small, greater than.equal 2-inch diagonal products such as projection light valves and camcorder viewfinders. Larger display applications, both personal TVs and office automation equipment, will use MIM active matrix technology. Seiko is convinced that they can compete with a-Si TFT technology for large-size displays with equal performance but substantially lower costs.
Seiko has been a supplier of specialized p-Si displays for avionic applications with sizes as large as 96 mm x 88 mm. They will continue to fulfill their contractual commitments but do not intend to expand either in display size or avionic market penetration.
Seiko uses a high-temperature (HT) p-Si process on quartz substrates. There is ongoing research to develop a low-temperature poly process that would permit the use of glass substrates. The products they currently produce using the HT p-Si process are as follows:
The basic LV is denoted EF01. It has integrated drivers and has approximately 25 leads. The integrated drives are located outside the LC seal area in order to prevent LC degradation by the dc voltages used in the drive circuitry.
These are special displays built under contract to a U.S. company. One is a 3ATI display for a TCAS (traffic collision avoidance system), and the other is a 96 mm x 88 mm monochrome display for avionic data applications. These displays will be produced as per the customer contract, but no further production of special-purpose avionic displays is desired or planned. Epson plans to focus on viewfinders and projection light valves.
No expansion of Seiko's p-Si production facility is planned. Their current size capability is limited to about 5" x 4.5", and no size capability increase is planned.
Seiko has decided that the MIM technology will be their approach for TV and OA applications requiring AMLCDs larger than 2-inch diagonal. MIM active matrices will have performance equivalent to a-Si TFT active matrices at very much lower manufacturing costs. They are continuing their MIM research. The advances they seek are reduced capacitance and reduced leakage (cause of cross-talk). Current MIM products are described in Seiko's brochure and summarized in Table Seiko.2.
Current MIM Products
For these color products, Seiko produces its own color filters. For the 9V color PC display, this filter is on top of the ITO stripes, thereby reducing the voltage across the LC and resulting in a narrow viewing angle. In the TV displays, the ITO is on top of the color filter, thereby providing maximum voltage across the LC material and resulting in a wide viewing angle. Another distinction between the 9-inch PC unit and the 4-inch TV unit is that the former operates in the normally black mode and the latter in the normally white mode.
Seiko is producing a p-Si AM light-valve projector - Model VPJ-2000. Light-valve transmission is approx. 15% (polarizers approx. 40% and aperture ratio approx. 40%). The unit uses a 150-Watt metal halide lamp and provides 70 lumens output. (See section on p-Si for light-valve specifications. According to Seiko, if lamp power were increased to increase the light output, then the increase in light-valve temperature would limit the maximum output. Specific details on light absorption were not provided.
We were given four demonstrations:
Both horizontal and vertical cross-talk were clearly visible.