Two for the price of one: Mitsubishi has developed a prototype LCD panel module called the "Reversible LCD" that can display images on both its surface and reverse side.

Press Release:

Mitsubishi Electric Develops 'Reversible' LCD Showing Images on Its Surface, Back Side

February 23, 2004 (TOKYO) -- Mitsubishi Electric Corp has developed a prototype LCD panel module called the "Reversible LCD" that can display images on both its surface and reverse side.

'Reversible LCD' by Mitsubishi Electric

For example, a mobile phone with a reversible LCD has the same function as a cell phone with two displays. Moreover, the mobile phone with the reversible display is thinner than a cell phone with two conventional LCDs by around 1mm. The price of the reversible LCD is expected to be about 1,000 yen higher than that of a conventional LCD panel. (105.44 yen = US$1)

In addition to mobile phones, Mitsubishi plans to use the new LCD panel for other products, including PDAs and laptop PCs. This technology can be applied to any transmissive or semi-transmissive LCD panels, Mitsubishi said.

The reversible LCD panel has a structure in which the LCD panel is sandwiched between two light-guiding plates. The light from the light-emitting diode (LED), which is reflected by a light-guiding plate, penetrates the LCD panel and the other light-guiding plate, making the images visible.

Because the conventional light-guiding plate is not transparent, just like frosted glass, the light cannot penetrate it. The transparent light-guiding plate, which Mitsubishi Electric newly developed, enabled the company to create the reversible LCD panel that can display images on both sides.

The prototype of the reversible LCD panel module displays different images on each side. The images for its surface and rear are displayed on one LCD panel alternately, and the back light is turned on and off according to which side of the panel displays the images. The frame rate of the panel is 60 frames per second for each side of the panel, or 120 frames in total.

The specific date for putting the LCD panel on the market has yet to be set. At present, the timing of turning on and off the light and that of switching the displaying side of the LCD panel are out of synchronization, sometimes creating stripes on the screen. Mitsubishi Electronics hopes to start shipments of the LCD panel by the end of 2004 if the company can solve this technological problem by then.




The main display




The sub display with a different image

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(Naoki Asakawa, Staff Editor, Nikkei Electronics)