Forget everything you've heard about the microprocessor being the most important part of a computer. When it comes to a notebook, the display rules.

Take a good lookat the screen on your notebook computer and think about how much you take it for granted. The screen clings to your notebook by the tiniest of hinges yet wields a lot of power.

More significant than a smoking-fast microprocessor or even a high-capacity hard drive, the display dictates nearly every aspect of notebook design - from its size and weight to the clarity of the images it presents, the power it consumes and the size of the keyboard it houses.

Given the pace of technology, that display is not going to stay the same forever, though. For one thing, prices for notebook liquid-crystal display (LCD) panels have been spiraling downward with dizzying speed.

Screens are getting bigger as vendors push the envelope of notebook design, and even the commonplace thin-film-transistor (TFT) screen soon may give way to such new technologies as organic LED or thin CRT, should they be perfected in the near future.

LCDs are found in just about every gadget, from beepers and calculators to handheld devices and data projectors. And notebook displays come in all shapes and sizes. Recently, the 12.1-inch screen, by far the most popular of display sizes, has lost ground to the 13.3-inch version, reports DisplaySearch, a flat-panel research firm based in Austin, TX.

The bottom line is that today's notebook LCDs are cheaper, thinner and larger than ever before, and the marketplace has never been in more turmoil. Plummeting prices, currency swings in Asia, a multitude of size options and a shortfall of units all threaten to disrupt the 12.1-inch display's reign and, therefore, muddy the waters for buyers.

Fire-Sale Prices

Formerly one of the most costly elements of a notebook, LCDs are now among the cheapest. For example, a quick check of the price sheet from Laptop Computer Displays (www.buyLCDs.com), a display-replacement seller, shows just how inexpensive displays have become: Some units cost as little as $300. In the past year, LCD prices have been in a freefall, dropping by 50 percent to about $220 for a 12.1-inch screen, which at first glance seems like good news for the buyer.

The glut has helped drive down the price of notebooks, even among high-end lines, but according to Ross Young, president of DisplaySearch L.L.C., display makers have been pricing screens about $30 below cost.

Prices aren't the only thing shrinking. On desktops worldwide, displays are cutting a slim profile. But if 3-inch-thick desktop monitors are impressive, then the multi-millimeter LCDs of notebooks are downright awe-inspiring, as are the lightweight notebooks that they spawn. Sony's VAIO 505 notebook, for example, weighs less than 3 pounds and is just under an inch thick, thanks in part to its 10.4-inch active-matrix screen.

The Hewlett-Packard OmniBook Sojourn, manufactured by HP's partner, Mitsubishi Electronics of America Inc. of Cypress, CA, was among the thinnest of the thin, coming in at three-fourths of an inch thick. Even so, the unit boasted a 12.1-inch SVGA thin-film transistor (TFT) and weighed a mere 3.2 pounds.

Hewlett-Packard of Palo Alto, CA, discontinued the ultrathin Sojourn after a 10-month product cycle, says Greg Munster, director of product marketing for the company's mobile computing division. Sojourn's replacement is the OmniBook 900, which comes in at one and one-quarter inches thick.

"Sojourn was an exotic design, using leading-edge technology," Munster explains. To get Sojourn down to size, designers had to put connection ports in an inch-thick media slice. "Only a small population wants the extreme."

or instance, where workspace is at a premium, the need is for smaller but clearer screens. And dots per inch is a more important factor than screen size when it comes to displaying the kanji characters used in the Japanese language.

In the United States, on the other hand, bigger is generally better. "The 14.1-inch displays will overtake 13.1 by the second quarter of 1999," asserts DisplaySearch's Young. And Dell Computer Corp. of Round Rock, TX, with its Inspiron 7000, already has shown that a 15-inch display is possible in today's market.

But such machines are aimed at the desktop-replacement market, notes Phil Ventimiglia, product manager at Dell. "So it's not critical for a machine to be under 6 pounds," he notes. "With a 15-inch screen, you have close to the viewing area of a 17-inch monitor in a portable form factor."

Too Big Is Too Much?

Though analysts may see bigger screens, not all vendors do. In general, notebook screens measuring 14 inches diagonally appears to be the limit among users. "Customers are not asking about bigger displays anymore," HP's Munster says. Corporate customers are more interested in value than in bigger screens. "They don't value bigger displays, but they do value more RAM," he adds.

Unfortunately, because most of an LCD screen is glass, as the display grows so does the notebook's weight, which is a burden to the road warrior who wants to travel light. For example, IBM's ThinkPad i Series Model 1450 features an ample 13.3-inch TFT screen but weighs 7.7 pounds; the Micron TransPort Trek2 300 may have a whopping 14.1-inch screen, but it weighs 8 pounds; and the 15-inch class of notebooks comes in a 10-pound package.

Prices for larger, active-matrix screens also carry a premium. Yet, lower-resolution passive-matrix screens appear to be history to all but the most cost-conscious of users - students and small-business owners, for example. (See "Value at What Cost?" in this issue.)

Toshiba put a 12.1-inch passive-matrix display on its Satellite 2515CDS notebook, which sells for about $1,500, less than many similarly equipped units with active-matrix screens. Just two years ago, passive-matrix displays accounted for 40 percent of the marketplace, notes Dave Mentley, a vice president at Stanford Resources. They held steady at 25 percent for quite a while after that but dropped recently to 20 percent, he says. Notebook vendors instead want to deliver higher resolutions with active-matrix TFT screens.

Today 75 percent of notebooks are TFT models, but next year that number should rise to 85 percent, DisplaySearch's Young believes. Asian companies have all but locked U.S. display makers out of the notebook LCD market, with Sharp, DTI (a venture between IBM and Toshiba), Samsung, Hitachi and LG Electronics being the major players. Unable to compete with low prices and the superior production techniques of large Asian electronics companies, U.S. companies bring in their displays from abroad.

The glut of 12.1-inch panels caused prices to fall below cost for many first-tier manufacturers. As a result, second-tier manufacturers picked up production, Young observes. "First-tier manufacturers are focusing on larger displays where they can get some profit margin," he adds. While DisplaySearch forecasts a shortage of LCD panels in the third quarter of this year, Young says that as the Japanese yen appreciates, demand for the screens should dampen.

Sony Electronics of San Jose, CA, is one vendor that has quit using 12.1-inch screens for its notebooks, preferring to stick with larger displays. "The key reason for us is product differentiation," explains Mark Hanson, director of mobile marketing for the IT marketing division at Sony. F series notebooks are a case in point.

They are up-to-date in every area, from the Pentium processor (333- or 366MHz) to the 14.1-inch screen. All told, the system weighs a mere 7 pounds and contains floppy and hard drives and a CD-ROM. The line ranges from $1,699 to $3,299.

Sony also is using an innovative polysilicon production process to increase resolution in its LCD screens and to cut screen thickness without losing brightness, Hanson says. By using polysilicon, Sony can trim the thickness of its VAIO 505 notebook to 0.8 inches from 0.9 inches.

Sony also is moving to market an ultra-mininotebook called the VAIO C1 PictureBook, which is smaller than the VAIO 505 (see Beta View "Picture This: The Notebook for Shutterbugs" in this issue).

The new machine will have a long, narrow screen with a 16:9 aspect ratio that can display 1,024 by 480 resolution. The landscape screen offers the width of XGA resolution to accommodate a reasonable keyboard and the height of VGA resolution.

An influx of oddball display sizes from new market players may create a bit of a quandary for notebook vendors, who already find it difficult to deal with today's wide variety of screens. In the rush to satisfy users, display makers have produced a hodge-podge of displays with very little - if any - thought to standards.

For instance, there are well over 100 12.1-inch displays on the market, all with slightly different parameters. This adds to production costs at the manufacturer and adds to repair costs at the user level.

At the Flat Information Displays conference in Monterey, CA, last fall, Dell Computer Corp. called for standards for flat-panel displays on notebooks. With the considerable clout as the number-four notebook vendor in the United States, Dell might be able to push the standards effort through, if it gains the support of its competitors.

With standards in place affecting the points of connection and electrical requirements, notebook vendors would be able to offer various screens to suit different user needs without altering manufacturing processes. If standardization comes to pass, buyers would be able to find replacements for broken screens quickly and easily.

In the meantime, several technological innovations may offer users more viewing space without increasing notebook size and weight. Displaytech and Hewlett-Packard have joined forces to develop reflective micro-display components for small screens, in which the display itself is postage stamp-size. Text and graphics, however, appear much larger when seen through a special viewer.

Small Steps to the Future

In the meantime, several technologies are progressing. IBM Corp. of Armonk, NY, is taking the same approach, but with TFT technology. Discounting the display and the keyboard as factors, IBM has managed to build a prototype that - while the size of a Sony Walkman - has the characteristics of a ThinkPad 560.

The package weighs 11 ounces, notes Phil Hester, chief technology officer of IBM's personal systems group. With the wearable ThinkPad, a TFT panel measuring only a half-inch square is attached to magnifying optics that produce a virtual image, which appears to the eye to be the equivalent of a conventional 15-inch screen. "The manufacturing infrastructure for TFT is largely paid for,"Hester says, which makes the technology economical to work with while allowing for innovation.

"It's a pretty good horse to ride on for a while," he says. Organic LED looks promising as well. Combining blue, red and green light-emitting diodes to get a white-screen background, organic LED consumes only one-fourth of the power that a TFT screen does, but IBM's Hester does not see it becoming an alternative to TFT for several years.

HP, on the other hand, sees promise in thin CRT technology. "CRT technology is incredibly cheap but not portable," HP's Munster says "Thin CRT is very low-cost. The $99 desktop display rivals the quality of what we have today (on notebooks)."

But while thin CRTs have been shaved down in the lab to 1 inch thick, many technical hurdles remain before thin CRT becomes mainstream. Whether screens get larger or smaller, notebooks are on the brink of profound design change. Eliminating the need for screens to accommodate tired eyes - and keyboards to oblige tapping fingers - will allow the notebook computer to slim down to the size of a paperback book. The question is when, not if.