[FPDI] MEMS Display Doubles as Transmissive, Reflective Displays

Oct 28, 2011
Shinichi Kato, Technical Writer
When the ambient light is turned off, the backlight of the display is turned on.
When the ambient light is turned off, the backlight of the display is turned on.
[Click to enlarge image]
When the ambient light is turned on, the backlight is turned off.
When the ambient light is turned on, the backlight is turned off.
[Click to enlarge image]
Pixtronix displayed an image on both Apple Inc's "iPad 2" and the MEMS shutter-based color display to emphasize the low power consumption of the color display.
Pixtronix displayed an image on both Apple Inc's "iPad 2" and the MEMS shutter-based color display to emphasize the low power consumption of the color display.
[Click to enlarge image]

Pixtronix Inc introduced a display that can realize two kinds of display modes by using its MEMS shutter-based color display technology at FPD International 2011.

In one mode, the display functions as a transmissive display that uses backlight. And, in the other mode, it functions as a reflective display that uses ambient light.

Pixtronix uses MEMS shutters for both turning on/off light and creating red, green and blue (RGB) colors. In the case of LCD panels, liquid crystal and polarizing plate are used to turn on/off light, and color filters are used to create RGB colors.

This time, Pixtronix combined its color display with an illuminance sensor, etc and enabled to switch display modes in accordance with ambient illuminance level and types of contents to be displayed. For example, it became possible to switch between the transmissive and reflective modes in accordance with ambient illuminance level as well as to reduce resolution or color gradation depending on types of contents.

As a result, the company realized a display suited for the environment in which it is used and reduced power consumption.

Also, Pixtronix displayed an image on both Apple Inc's "iPad 2" and the MEMS shutter-based color display for comparison. The company stressed that it improved image quality and enabled to reduce power consumption by 75% in comparison with LCD panels, etc.

The reason why the MEMS shutter-based color display consumes less power is that it does not require color filter or polarizing plate. As a result, it becomes possible to efficiently transmit light from the backlight, compared with LCD panels.

So, when the brightness of the color display is the same as that of an LCD panel, the brightness of the color display's backlight is lower than that of the LCD panel's backlight, contributing to reducing power consumption.

The MEMS shutter-based color display can be mass-produced at existing manufacturing lines for amorphous Si-TFT LCD panels, Pixtronix said. Because the color display does not use color filter or polarizing plate, it has a cost advantage. But the company did not disclose further details.

Currently, Pixtronix does not have a plan to mass-produce the color display in house. And it has already licensed four companies including Samsung Electronics Co Ltd, Chimei Innolux Corp and Hitachi Displays Ltd for the production of the color display.