Proliferation of LCDs spawns new applications

Major liquid-crystal-display (LCD) manufacturers are now producing in overdrive, and prices are finally dropping quickly. As a result, these vendors are looking beyond the traditional laptop-computer market for new opportunities. The time may be right to take a fresh look at using flat-panel displays in a variety of markets such as laboratory instrumentation, industrial, aerospace, medical, automotive, and even desktop applications.

Proliferation of LCDs spawns new applications

Chris Chinnock

Major liquid-crystal-display (LCD) manufacturers are now producing in overdrive, and prices are finally dropping quickly. As a result, these vendors are looking beyond the traditional laptop-computer market for new opportunities. The time may be right to take a fresh look at using flat-panel displays in a variety of markets such as laboratory instrumentation, industrial, aerospace, medical, automotive, and even desktop applications.

According to a recent report in Nikkei English News, the prices of 10.4-in. color active-matrix LCDs for laptop computers has fallen about 50% in the last year. For this market-

driving application, volume users can now buy LCDs for $550 to $650--not far from a long-held goal of $500, at which many manufacturers would currently lose money. In addition, the premium users must pay for the better performance of an active-matrix device over a passive-matrix device is shrinking. "Color passive displays are still about half the price of active displays," says Tim Patton, Hitachi America (Norcross, GA) display business manager. "But that is now a $200-$300

differential instead of a $500-$600 one."

What is driving this reduction in price is an enormous buildup in manufacturing knowledge and capacity. David Mentley, display analyst at Stanford Resources Inc. (Palo Alto, CA), notes that "Japanese producers have more than doubled the amount of display area that can be processed in the last year. Shortages in laptop displays last year have disappeared." Manufacturers have also increased the size of the substrates upon which the displays are fabricated. This allows manufacturers to produce larger-sized displays or put more smaller-sized displays on one substrate, leading to more cost-effective production. In addition, major Korean manufacturers are now making a serious bid to supply these same displays in volume, and Taiwan may not be far behind them.

All of these factors add up to overcapacity in the LCD marketplace. Ken Werner, editor of the Society for Information Display industry magazine Information Display, says, "Many of these producers are looking at an overcapacity problem that may be more than 100,000 units per month. They need to find new volume markets for these displays."

What seems clear is that these flat-panel products are making a new push to replace many CRT-based systems. One of the major areas to which they are heading is the desktop. For example, the latest notebook display size is now about 12 in. in diagonal. But this size is also equivalent to the viewing area on a 14-in. CRT monitor. Patton wonders, "Will notebook owners be willing to pass on buying the CRT monitor and just dock their notebooks to a desktop PC? Maybe they won`t buy the desktop system at all. I don`t know." But if it pans out, this could expand the notebook market growth even further.

Larger-sized displays are also becoming available--mostly in the 13-16-in. range, but extending up to 21 in. in diagonal. Clearly, they will be expensive, but certain situations may allow their use. For example, with an engineering workstation, the additional display cost may be small compared to the overall system cost. If the display makes the system more portable, this could create new opportunities. "The big wildcard here is if these displays can become inexpensive enough to replace normal desktop PC monitors," says Patton. "I think it will take two to three years to see if that can occur."

The other approach manufacturers and end-use developers are pursuing is the expansion of niche or specialty markets. Whether these emerging applications can make a dent in the excess manufacturing capacity is still unknown, however. Often these products require a year`s design cycle, so a volume impact, if it occurs, is still probably two to three years off.

At the Hewlett-Packard (HP) Microwave Instruments Division (Santa Rosa, CA), active-matrix LCDs are already replacing CRTs in high-end instrumentation products. These include test-and-measurement equipment for electronics, gas/water, microwave/radio, telecommunications, and medical applications. Tim Kreigel, R&D project manager at that HP division, notes that "prices of color active-matrix LCDs are already lower than comparable 7.5-in. CRTs, and, with display prices falling like a rock, designers need to reassess the cost benefits of LCDs. Certainly instruments that sell for $10,000 and up should consider active-matrix LCDs, and that point is likely dropping quickly," he says.

There are a number of factors, other than price, that are driving instrument makers to replace CRTs with LCDs. For one, a CRT can take up as much as one-third the space and one-fourth the weight of an instrument. By going to an LCD, designers can either shrink the instrument or provide more functionality. Stray electromagnetic fields that can interfere with measurements are also eliminated. Active-matrix devices are preferred because of their wider viewing angles and faster speed of response compared to passive displays.

Kreigel thinks that many instruments in the near future will feature color, VGA-resolution (640 ¥ 480 pixels), active-matrix LCDs. "Portables will have 6.4-in. devices, and rack-mounted instruments will go for 8.4-in. models," says Kreigel. While these displays are available today, instrumentation displays have special requirements that are now being addressed (see "Nonlaptop markets need different LCDs." p. 122 ).

Another promising area for growth is in the financial-services market. Banks, brokerages, financial-information companies, and stock-trading exchanges all require many displays. Vic Odyrna, president of Pixelvision (Acton, MA), notes that "stock-trading floors have 500 to 1000 people on them, and each person has two to six CRT monitors. These CRT-based monitors take up a lot of room, which is at a premium for this type of application. Many of these users are already embracing the switch to flat-panel displays." Pixelvision adds the driving and interface electronics for a variety of display types to provide a plug-and-play replacement for CRTs (see photo on p. 124). It recently completed a major flat-panel-display upgrade for the New York Stock Exchange (see photo on p. 121).

Active-matrix LCDs are beginning to appear in automotive navigation systems, too. They are already popular in Japan, and now Hertz and Avis offer some rental vehicles in the USA with the dashboard-mounted units. When you enter your destination, the display shows a map and prompts you to make turns where necessary by tracking the car`s position with a global-positioning-system transponder.

Avionics applications are now embracing liquid-crystal displays, as well. For example, US vendor Optical Imaging Systems (Northville, MI) is supplying a variety of horizon and other indicator displays to replace more maintenance-demanding electro-mechanical indicators. Canadian display-supplier Litton Systems Canada (Etobicoke, Ontario) has established a new facility to fabricate active-matrix displays using cadmium selenide instead of amorphous silicon as the on-screen transistor-switching material. It is now supplying a variety of displays, mostly in the 6 ¥ 8-in. range, for tactical displays on military and commercial aircraft. These are direct replacements for CRTs.

While many of these new applications for LCDs are good businesses, they often do not attract much interest from high-volume Japanese manufacturers. But that may be changing. As HP`s Kreigel says, "If you add up all the potential for these niche markets, it starts to look pretty big--about the same size as the notebook market." n

At the New York Stock Exchange, more than 2000 PV467 flat-panel displays streamline information delivery to the trading floor.

The PV460 is reportedly the industry`s first active-matrix LCD for computer or video applications.

Nonlaptop markets need different LCDs

It turns out that the flat-panel-display requirements for emerging applications such as commercial instrumentation, transportation, military, and industrial control panels are quite similar. So far, though, the laptop-computer market has driven display needs. Here, the primary consideration is for portability, so reducing power consumption, size, and weight is critical. Many new applications will not need portability, however, so these criteria are not as important. In general, these new applications require larger sizes, more pixels, wider viewing angles, and brighter displays (see photo). But, clearly, they will benefit from on-going related efforts to improve laptop displays, too.

One of the most important needs is for brighter displays, because ambient lighting conditions are much less controllable. Today`s laptop displays are specified at 70 cd/m2, but instrumentation needs at least 120 cd/m2 of brightness; if a sunlight-readable display is desired, even greater brightness will be needed. This performance characteristic can be readily accomplished with brighter backlights. In many cases, the displays must also be modified to permit the backlights to be replaced.

Improved brightness can also be achieved by increasing the display transmissivity via the aperture ratio. By shrinking the on-screen pixel-switching electronics, more light can pass through the LCD. Sharp (Camas, WA) recently announced that it has developed LCDs that have a 70%-80% aperture ratio--well above the industry average of 50%-60%.

Increases in the viewing angle are also needed because of the odd angles at which products are commonly viewed. This criterion is not as important for laptop users because they generally sit directly in front of the display. Active-matrix displays today offer about 䕑° in the horizontal direction and about 䕂° in the vertical direction before they experience color image reversals. This performance is significantly better than for passive displays, which is one reason why active-matrix displays are preferable.

A new type of plastic film recently introduced by AlliedSignal (Morristown, NJ) improves the vertical viewing angles to perhaps 䕌°. In another breakthrough, Hitachi (Tokyo, Japan) has decided to commercialize a process that can achieve 䕖° of viewing angle in both the horizontal and vertical directions. The technique, known as in-plane switching, essentially changes the direction in which the liquid-crystal molecules rotate from a vertical to a horizontal orientation.

These displays need to be more rugged than their laptop cousins. Protecting the front surface

of the display from mechanical damage is of primary concern. Antireflection-coated glasses can be used, but interference and other optical effects can degrade performance. "Unfortunately, no easy solution currently exists," states a Sharp application note. In addition, extended operating temperature ranges are also required. So there are still technical hurdles in applying LCDs to nonlaptop applications.

C. C.

Super-VGA, high-aperture-ratio thin-film transistor display for laptop-computer applications has a diagonal of 10.4 in.

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