Seiko Epson Corp exhibited a prototype viewer terminal using electronic paper as a reference presentation at Embedded Technology 2007, an exhibition event in the Pacifico Yokohama convention center.
The terminal measures 180 x 120mm, which is about the size of a notebook (B6 size). Featuring a design with portability in mind, it is only 3mm thick and only weighs 57g. It is equipped with an USB port for USB-based data exchange. The commercialization schedule of the product has yet to be decided, the company said.
The display unit is equipped with a 6.7-inch screen with a resolution of 1200 x 1600. The screen features a definition of about 300ppi, contrast ration of 8:1 and reflectivity of 43%.
Each pixel can display black and white and represents gray-scale by area coverage modulation. The product was developed by combining the electrophoretic ink developed by E Ink Corp with Seiko Epson's proprietary low-temperature poly-Si TFT formed on a glass substrate.
The glass substrate was made thin to achieve product's slim profile and lightweightness. Although the original glass substrate on which the TFT is formed has a thickness of 0.5mm, it is cut to 0.2mm by etching.
To compensate for the degradation of strength due to the thickness reduction, Cute, a low CTE base substrate developed by Hitachi Chemical Co Ltd, is attached to the back side (opposite to the TFT formation surface) of the glass substrate. According to Seiko Epson, the base substrate is 50μm thick.
The terminal is driven by a button cell (CR1220). The screen can be redrawn for 1,420 times with one button cell because the electronic paper consumes power only when the display is redrawn. The time required for redrawing is 0.7 seconds. While the Seiko Epson's existing e-paper takes 5 seconds to redraw the screen, the company enhanced the redraw speed by improving the drive circuit, etc.