Classic Computer Magazine Archive COMPUTE! ISSUE 136 / DECEMBER 1991 / PAGE 106

Color video on the run. (color liquid-crystal-display laptop computers) (Column)
by David English

High-quality color LCD laptops have finally arrived, and I've got good news and bad news. The good news is that these latest color LCD screens are sharper and have less distortion than standard color monitors. The bad news is that the International Trade Commission plans to slap a heavy tariff on this promising new video display technology.

First, the good news. Toshiba, Sharp, NEC, and Dolch all offer color laptops--though they're currently expensive and run on AC power only. Fortunately, prices are dropping quickly (Toshiba's T3200SCX slid from $8,995 to $7,249 in just three months), and battery-operated versions should start popping up within the next six to nine months (Dell hopes to have one out by the end of the year, but that's a real long shot).

If you saw a color LCD screen in 1990 or 1989, look again. You probably saw a passive-matrix color screen using the same technology as the passive-matrix gray-scale screens that are so popular on today's laptops. Passive-matrix screens--either color or gray-scale--have only a 4:1 to 12:1 contrast ratio, so graphics and text appear to be washed out when compared to regular monitors.

Screens using active-matrix technology have a 100:1 contrast ratio, which is about the same as that of a regular color monitor. In addition, active-matrix screens switch their pixels on and off as much as ten times faster than passive-matrix screens (or about the same speed as a regular monitor), so you don't have those ghost images that make it hard to follow a moving cursor or find it in a field of text.

Best of all, because these new color LCD screens are immune to pin-cushioning, color bleeds, misconvergence, and magnetic interference, they actually provide a sharper image with better color saturation than a standard cathoderay tube (CRT) monitor. (You can expect to see wall-mounted color televisions based on this same technology by the end of the decade. Eventually, color LCD screens will replace our current CRT-based monitors and televisions.)

The current generation of active-matrix color LCD laptops offers various VGA graphics modes, including 320 x 200 with 256 simultaneous colors and 640 x 480 with 16 simultaneous colors. However, each system varies in the number of possible colors that are available for these modes.

The Dolch screen increases the palette for a color LCD screen from 512 colors to 24,389 colors by using a proprietary combination of pulse-width modulation and dithering. The Toshiba T3200SXC expands the palette to more than 185,000 possible colors. The Sharp PC-8501 offers a 256,000-color palette for 320 x 200 with 256 simultaneous colors and a palette of 4,096 colors for 640 x 480 with 16 simultaneous colors. The NEC Pro-Speed 486SX/C goes further, offering a Super VGA 640 x 480 mode with 256 simultaneous colors while limiting the available palette to 4,096 colors.

Expect 1992 to bring more available colors and more modes. Passive-matrix color screens may make a comeback on the low end as manufacturers grapple with the problems of making active-matrix color screens battery compatible (at present these screens use 1000 times more power than black-and-white passive-matrix screens). I wish I could say that prices will keep dropping, but that brings us back to our bad news.

At the time of this writing, the International Trade Commission has slapped a 62.67-percent tariff on Japanese active-matrix screens. A group of domestic LCD screen manufacturers has argued that Japan is dumping these screens on the American market at less than fair market value. IBM, Apple, Tandy, Compaq, and other computer makers have countered that American companies lack the necessary manufacturing facilities and expertise.

If the tariff is imposed, it will make it nearly impossible for American computer manufacturers to offer active-matrix screens over the next 6 to 12 months--unless they manufacture their computers outside this country. Most will simply move their manufacturing plants offshore. Presumably, the Japanese companies that are currently in the forefront of active-matrix color technology--including Toshiba, Sharp, and NEC--will be able to work around the tariff by manufacturing their laptops in Japan.