Flat Panel Displays

By Frank Hayes

ComputerWorld, November 29, 1999 - They’re sharper. They’re more compact and more durable. They use less electricity and pose fewer potential hazards for users. In fact, just about everything about flat-panel displays makes them better than the TV-like CRT monitors most people still use.

Except, of course, for the price.  The premium of several hundred dollars that a user must pay for a flat monitor over the price of a CRT monitor of the same size and resolution means flat panels are still specialty items. They’re mostly built into laptop computers, but are increasingly used in stand-alone displays.

Worth the Price?  LCD screens have several advantages compared with traditional CRT displays.  LCDs don’t waste space at the borders of the screen as CRTs do. A 15-in. LCD screen is the equivalent of a 17-in. CRT monitor.  LCD displays are much lighter than CRT monitors — 13 lb. vs. 40 lb. for a stand-alone CRT display.  LCD displays use much less electricity than CRTs — 25 watts vs. 130 watts.  A CRT's screen is covered with phosphor dots that are lit up one at a time; an LCD’s pixels are individually wired to light up independently.

Users in the U.S., ranging from Wall Street firms to the Mayo Clinic in Rochester, Minn., have begun to use stand-alone flat-panel screens to reduce the desktop space required by large monitors, which can be 18 in. or more deep (compared with 2 to 4 in. for flat-panel displays). And some users think the high-tech aesthetics of a flat screen are worth the cost.

Part of the reason for that higher price tag is that flat-panel technology is relatively new compared with CRT technology. The CRT hasn’t changed much in the past half-century, but the most common flat-panel technology, the LCD screen, keeps evolving.

A CRT is really just an electron gun — a stream of focused electricity — aimed at the back side of a screen covered with colored dots called phosphors. When the stream of electrons hits a dot, it lights up, then slowly grows dim again. The electron gun’s beam sweeps back and forth and from top to bottom across a CRT’s screen, shooting at specific colored dots to display an image.  But because the beam lights up phosphor dots one by one, CRT screens flicker slightly, even when the image isn’t moving. And the sharpness depends on the number and size of phosphor dots and how accurately the electron gun finds its target.  In contrast, every pixel on an LCD flat-panel display is separately wired and can be turned on or off independently. That eliminates flicker — but it raises the cost of building the display.

Improvements in LCD manufacturing technology are pushing the price-per-pixel down, and LCD screen makers are also getting the benefits of economies of scale. The number of LCD screens made should jump from 3.9 million units this year to 10 million in 2001, according to market analysis firm DisplaySearch in Austin, Texas.

But another thing that raises the cost of LCDs is the fact that the display units aren’t interchangeable.  LCD screens from different manufacturers require different wiring; even the holes for mounting screws are in different positions. That means laptop and stand-alone display makers must retool to use LCD screens from different sources.  That’s about to change. In October, five laptop makers agreed on a standard for electrical and physical flat-screen specifications. Compaq Computer Corp., Dell Computer Corp., Hewlett-Packard Co., IBM and Toshiba Corp., who together hold more than half of the laptop market, formed the Standard Panels Working Group last year and hashed out an agreement in a few months.  Many major LCD screen makers have agreed to conform to the new standard, and LCD displays that match it should begin appearing by August. That should help push prices down by 40% to 50% by the end of 2001, says Ross Young, president of DisplaySearch.

Another change that will cut costs for stand-alone flat screens is the shift from analog display interfaces, such as PC-standard VGA, to digital. CRTs are designed to use analog interfaces, while LCD displays are digital; stand-alone flat-panel displays must convert analog signals to digital, requiring extra circuitry.  Expect to see both PCs and monitors with both analog and digital connections in the next year, says Rhoda Alexander, an analyst at Stanford Resources Inc. in San Jose.