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Touchscreens, 3D, OLEDs drive new displays

Posted: 16 Jul 2007 ?? ?Print Version ?Bookmark and Share

Keywords:3D holographic display? display market? OLED? touchscreen?

A touchscreen that can withstand manhandling at a toll booth was among the developments on view at last May's Society for Information Display (SID) conference. Along with touchscreen advances, SID played host to novel developments in 3-D holographic displays and in screens based on OLEDs.

QSI Corp.'s InfiniTouch claims to enable any semi-rigid substancemetal, glass, wood, stone, ceramic, plastic or any combination of these materialsto sense touch. "For nearly 40 years, engineers have worked to develop a commercially viable, force-based technology. QSI has achieved success with the InfiniTouch," said James Elwell, QSI's chief operations officer and InfiniTouch's co-developer.

According to Elwell, the InfiniTouch technology solves the problems of how to handle the non-orthogonal nature of touch and how to adjust for force variations. InfiniTouch is the only technology that directly measures the force of a user's touch rather than using a complex, indirect method that relies on translation, Elwell said. Location and force are determined by four force sensors near the corners of the touch surface. Any semi-rigid material of any shape can become touch-sensitive.

InfiniTouch is being field-tested at the toll road operations in California. Each toll booth attendant averages 100,000 presses on the panel per month.

"Sensitive contact points quickly wore out, rendering the touchscreens inoperable," said Elwell. "The glass touch surface and sensor configuration of the InfiniTouch Force Panel Technology consistently delivered 100 percent performance touch after touch."

Meanwhile, Immersion Corp. has made its TouchSense tactile feedback available for portable devices. Comprising circuit and mechanical specifications, firmware, APIs and vibration or tactile "effect" libraries, TouchSense provides high-speed control over a small electromechanical actuator, like those in mobile phones.

Using the TouchSense API, the portable device's software application is programmed to respond to touch input by making calls to the TouchSense executable, running in the background on the host processor. The executable generates signals through the Immersion-specified drive circuit, which controls the vibrations of the actuator, mounted to the side or rear of the display. These finely tuned vibrations create sensations that can feel to the user like a button press or release.

The TouchSense system works with touchscreens up to about 6 inches on the diagonal, or 198g. Immersion also supplies similar technology for larger touchscreen designs.

For its part, RPO Inc. has made its Digital Waveguide Touch products available for integration into a range of information systems. RPO's polymer optical waveguide features a low-power semiconductor light source, which distributes infrared light via a number of waveguides to the bezel of a flat-panel display. The light is then projected through free space, and illuminates reciprocal waveguides behind the opposing bezel. Any interruption of the light beam is instantaneously detected by a light sensor camera.

The chemical composition of the polymer allows RPO to process waveguides in a proprietary fabrication process that leverages manufacturing techniques developed for the LCD and telecommunications industries. "Using waveguides is new to the display industry, and it is a truly digital solution from finger to detector," said CEO Malcolm Thompson.

Holography for TV
Among the more unusual developments, SeeReal Technologies tipped a revolutionary approach to computer-generated holography for TV and projection displays. "Since the only alternative able to perfectly substitute for natural viewing is holography, SeeReal has spent the last four years developing an approach that overcomes the obstacles that have historically kept holography from mainstream displays," said SeeReal's chief scientific officer, Armin Schwerdtner.

SeeReal does holographic imaging in so-called "tracked viewing windows," limiting pixel size to levels already known for HDTV applications. In combination with real-time encoding of subholograms, the technology eliminates superfluous elements while reducing the requirements for real-time computing. This concept basically breaks up a large holographic picture into smaller units and processes them for direct view (desktop or TV) as well as for use in projection imaging.

On the OLED front, MicroEmissive Displays Group plc has packed a 0.24-inch color polymer-OLED QVGA display in sunglasses and hooked it up to an iPod via earphones. "One can watch Shrek 3 lounging around anywhere, while people around you might think you are listening to Fleetwood Mac," said Ian Underwood, co-founder of MicroEmissive and co-inventor of its polymer-OLED microdisplay technology.

Because the technology is emissive and does not require a backlight, the company's ME3204 can be used in portable applications such as video glasses or head-mounted displays, electronic viewfinders and night-vision systems. The microdisplay is combined with magnifying optics to produce a large virtual image that appears to the eye to be equivalent in dimensions to the picture on a TV screen or computer display. The ME3204 features a digital video interface together with an integrated display driver, eliminating the need for additional driver ICs.

Kopin, a microdisplay developer, showed its 3001AD's 2-D virtual-reality game, Trimersion, a wireless unit that connects to game consoles.

Sony's flexible 2.5-inch prototype uses 120 x 160 pixels and 8bit grayscales to deliver a full 16.8 million colors. SeeReal brings computer-generated holography to the TV.

Sony has developed what it says is the first full-color active-matrix OLED display on a flexible plastic substrate. An organic TFT backplane on a glass substrate was reproduced on plastic film. Sony used C22H14 pentacene material to form organic transistors with 0.1cm?/Vs mobility. The prototype is a 2.5-inch display with 120 x 160pixels and 8bit gray scale, to deliver a full 16.8 million colors. The electrodes were fabricated before the organic TFT layer, without damaging the semiconductor layer.

Philips spin-off Liquavista, which is developing displays based on its patented HEOS technology, showed its ColorMatch platform in two concepts: a watch and a large-area signage product. "We are showing our first-generation watch module, driven with commercial silicon and powered off regular watch batteries," said Anthony Slack, VP of business development at Liquavista.

"Our engineers have developed drive schemes which have reduced power consumption by an order of magnitude," needed for an "always on" application like watches, said CEO Mark Gostick.

- Nicolas Mokhoff
EE Times

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