Where Computer Display Technology is Headed

By Drew Robb

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Perhaps the least exciting part of computing is the one we spend the most time interacting with -- the display.

CRTs have been around for ages and still dominate the desktop. Sure, the current ones are higher-resolution and more energy-efficient, but they don't get your heart racing. Then there are LCDs, which are a bit newer, but still pretty mundane.

There are, however, five other emerging display technologies that will change the way to look at computing.


One new technology just hitting the market is Organic Light Emitting Diodes (OLEDs). This is a flat-panel technology similar to LCDs, but the image quality is far superior. An LCD screen uses a backlight and the LCD matrix acts as an array of mini-shutters to selectively block portions of that light in order to create the image.

The matrix doesn't do a very good job of blocking out the unwanted light, though, so it results in the image being a bit washed out. LCDs also have a slow response time, resulting in some smearing on moving images.

With OLEDs, however, there is no back light. Rather, the pixels on the matrix directly emit the light. This produces a brighter, higher-contrast display. In addition, they have a microsecond response time so images don't smear the way they do on LCDs.

"OLEDs offer wide viewing angles and very fast response times so they pick up changes in video images without producing jagged edges," Barry Young, vice president and CFO of Display Search, an Austin, Texas-based research firm covering the display market. "The image is so pure and beautiful."

While the OLED market has reached nearly a quarter-billion dollars, the technology is not widely available yet in the United States. Kodak is using the technology on one of its digital cameras sold overseas, and it is available on some cell phones. One place where you can see OLEDs in use is on certain Pioneer car stereo displays.

So when will we see them used with computers? Not too soon. It's not a matter of cost, but of the current state of development. The chemicals employed break down with usage. Eastman Kodak, which makes the chemicals, has boosted their life span into the 8,000- to 10,000-hour range when showing dynamic content such as movies. The life span is as much as 10 times shorter when the display is used for black text on a white screen, since all the pixels in the white background are turned full on most of the time.

In addition, static images, such as those in the task bar, will burn in over time. This limits its use to devices, such as cell phones and cameras, which are only on part of the time. Dan Gisser, Kodak's Director of Strategic Marketing for OLED products, says the company is working on developing longer-lasting chemicals, but that it will still be three to six years before they will be good enough for use in televisions or computer monitors.


While it will be a few years before you can get an OLED laptop, you can get a 3D one today. In October, Sharp Electronics released the Actius RD3D notebook with an LCD screen that switches between 2D and 3D modes. At $3,000, it costs about $700 dollars more than a comparable notebook without the 3D screen and software. Japanese telecom NTT DoCoMo also offers the 3D display on a cellphone, selling more than 1.5 million units in the first six months.

The user doesn't need to wear a headset or special glasses to view the 3D images, but does need to be located in the proper position, dead center and 21" from the screen, for optimal effect.

Ian Matthews, 3D Business Development Manager for Sharp Systems America, says the initial market for RD3D is for applications such as molecular modeling, advanced medical imaging and computer-aided design. These applications already consider objects to be three-dimensional; it's just a matter of translating that to the screen image.

The 3D Consortium (www.3dc.gr.jp/english/) formed last year with 150 companies to develop further hardware and applications using this technology.

Digital Light Processing

For large-screen displays, there is Texas Instruments Inc.'s Digital Light Processing (DLP).

The core of this technology is a chip containing 1.3 million minute mirrors. A light shines on this chip and each mirror goes to either an on or off position to create the image -- either directing a pixel of light at the screen, or leaving it black.

If it is on all the time, it is fully bright. But the mirror can switch between on and off several thousands of times per second. By varying the amount of time it spends in the on and off positions, it creates up to 1,024 levels of brightness. The technology is available as either a standalone projector or in a digital television format. A 60" to 70" diagonal screen is little more that a foot deep.

Bistable Displays

Bistable displays are useful for situations where the data doesn't change very often. A primary drawback is that they can only display two colors, which is where the "bi" part of the name comes in. The "stable" part of the name describes the primary advantage.

Unlike other types of displays which constantly require a source of power, bistable displays only require energy to change the content. The image remains visible even after power is cut off. Bistable displays are useful for things like eBooks or in store signage, but not for anything with rapidly changing information.

Field Emission Displays (FED)

CRTs offer a bright image, but they are big and clunky. If you want a big screen, it uses all your desk space because of the distance the cathodes inside the picture tube need to be from the screen. The bigger the screen, the further back the cathodes. LCDs solve the space problem, but are not as bright and have a limited viewing angle.

FEDs offer the best of both. Instead of having a single set of cathodes to paint the entire screen, they contain an array of cathodes each covering just a portion. This lets manufacturers create large CRT displays that are as thin as LCD monitors.