[SID] Entire Surface of Handset Becomes LCD Display

Jun 9, 2009
Tetsuo Nozawa, Nikkei Electronics
The coloring and structure of the "Electronic Skin"
The coloring and structure of the "Electronic Skin"
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A comparison between the previous and new technologies
A comparison between the previous and new technologies
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The demonstrated mobile phone mock-up (in blue)
The demonstrated mobile phone mock-up (in blue)
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The same mock-up turned into lavender color
The same mock-up turned into lavender color
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Kent Displays Inc of the US announced a technology to form its cholesteric liquid crystal display (ChLCD) on almost the entire surface of a mobile phone at SID Display Week 2009.

The technology is called "Electronic Skin" and was developed to realize the concept of "display everywhere," which means forming a display on the surface of any object.

The ChLCD technology of the Kent Displays can be applied to displays using reflection of light. It is also used for electronic paper because content on the screen does not disappear even when the power supply is cut off. In Japan, Fujitsu Ltd developed a color electronic paper with the technology licensed by Kent Displays.

This time, Kent Displays made a presentation about the technology to form the ChLCD on free-form surfaces. Specifically, it forms cholesteric liquid crystal on a flexible substrate as three layers of red (R), green (G) and blue (B) in this order by using roll-to-roll technology.

There are thin resin layers between the three layers so that liquid crystal layers are not damaged even when bent. The thickness of the panel (from the substrate to the sealing layer) is as small as 65 to 70μm.

To form the panel on a free-form surface, heat forming is used. In other words, a heated panel is pressed onto the surface. According to Kent Displays, this method does not affect the properties of the liquid crystal.

"In principle, there is no limit in terms of resolution either," the company said.

This is not the first time that Kent Displays announced this technology. However, the company improved colors by 120% in terms of the area in a chromaticity diagram and the reflectance by 5%.

Next version can display 4,000 colors

In the exhibition site, Kent Displays exhibited a mobile phone mock-up made with this technology. In a demonstration, the color of almost the entire surface of the mock-up changed in an instant when a button on the chassis is pressed. Power is consumed only at the moment of the color change, according to the company. With the RGB layers, it is possible to display up to eight colors.

"The technology used for this mock-up is not capable of gradation expression," Kent Displays said. "But the next version of the technology, which will be released in several months, can use gradation expression and display up to 4,000 colors."