Sharp's MEMS-shutter display
Sharp's MEMS-shutter display

Sharp Corp will exhibit prototyped color displays that use MEMS shutters in place of LCD shutters to reduce power consumption at Ceatec Japan 2013, which will take place from Oct 1 to 5, 2013, in Chiba Prefecture, Japan.

Different from conventional LCD panels, the new displays eliminate the needs for a polarizing plate that reduces the transmittance of backlight by half and a color filter that reduces it to 1/3. As a result, it becomes possible to reduce the power consumption of a panel to 1/6 that of a conventional LCD panel.

This time, Sharp will show three 7-inch MEMS-shutter displays with a pixel count of 800 x 1,280 and resolution of about 220ppi. The company plans to show that each of the displays has a low power consumption when it is displaying a still image, video or black-and-white image. Sharp developed the three displays in collaboration with Qualcomm Inc.

The mechanism of the new displays is as follows. LEDs are used for the backlight. The MEMS shutter formed for each pixel is opened and closed in a time-sharing manner to control the transmittances of red, green, blue and white (RGBW) lights and realize color display.

In the aim of moving the MEMS shutters at high speeds, Sharp employed IGZO, an oxide semiconductor whose carrier mobility is higher than that of amorphous silicon (Si), as a semiconductor material of the switching TFT. Amorphous Si is commonly used for LCD panels.

When an image with fewer levels of gradation or black-and-white image is displayed, the MEMS shutters are opened and closed less frequently, improving the use efficiency of backlight and further lowering power consumption.