[Ceatec] Hitachi Displays Announces MEMS Display

Oct 5, 2010
Shinya Saeki, Nikkei Electronics
The MEMS display prototyped by Hitachi Displays (color display in the transparent mode)
The MEMS display prototyped by Hitachi Displays (color display in the transparent mode)
[Click to enlarge image]
The MEMS display (monochrome display in the semi-transmissive mode)
The MEMS display (monochrome display in the semi-transmissive mode)
[Click to enlarge image]

Hitachi Displays Ltd prototyped a MEMS display by using Pixtronix Inc's technology and showed it at a press conference Oct 4, 2010.

The display was prototyped on the 4.5-generation (the size of glass substrate: 730 x 920mm) production line for low-temperature polycrystalline silicon in Chiba Prefecture, Japan.

"Compared with LCD displays, the power consumption of the new display is about half," Hitachi Displays said. "And it can reproduce vivid colors."

The company plans to release the display from the end of 2011 to the beginning to 2012 for mobile phones, smart phones, tablet PCs, digital cameras and other mobile devices equipped with a 10-inch or smaller display.

Pixtronix's MEMS display consists of a MEMS shutter, a backlight unit using red, green and blue LEDs, driver elements (TFTs), a reflecting plate, etc. Color tones can be adjusted by opening and shutting the MEMS shutter at a high speed and changing the amounts of the light from the LED backlight unit and natural light (See related article).

Pixtronix's display can be driven in three modes: the transparent mode, the reflectance mode and the semi-transmissive mode, which is a combination of the transparent mode and the reflectance mode.

In the transparent mode, color display is realized by driving red, green and blue LEDs in sequence (field sequential method). In the reflectance mode and the semi-transmissive mode, which use natural light, only monochrome display is possible.

Unlike LCD displays, the new MEMS display developed by Hitachi Displays does not require a polarizing plate or a collar. In addition, when light is extracted, it is repeatedly reflected inside the panel, resulting in a high light use efficiency, the company said.

"While the aperture ratio of LCD displays is as high as 40%, their light use efficiency is only about 6%," Hitachi Displays said. "Though the aperture ratio of the new MEMS display is 12%, its light use efficiency is as high as 60% because of light reflection."

The prototyped display has a screen size of 2.5 inches, a pixel count of 320 x 240 (QVGA), a pixel pitch of 163μm and a 120% color gamut on NTSC standards. The company did not disclose other specifications. Hitachi Displays will exhibit the prototype at Ceatec Japan 2010, a trade show that runs from Oct 5 to 9, 2010, in Japan.