Technology Showcase: LCDs and Plasma Displays
Jun 1, 2004 12:00 PM, By Jeff Sauer
There's been a lot of talk during the past year or two about a looming battle between LCD and plasma in the large flat-panel display business. It's a format war of sorts, and that makes for good conversation and certainly good press copy. Yet surprisingly, despite all of the prognostication, the only real battle is one of words and not products, at least in the professional AV market.
LCD has made progress recently, to be sure, but in the consumer market with LCD-TV products. Where are all of the large-panel LCDs for the professional AV space? Aren't LCDs supposed to be replacing plasma in public signage and commercial and industrial installations? Why are manufacturers continuing to announce newer and bigger plasma monitors if LCD is positioned to overtake plasma in the large-panel market? Why are most pro-AV display companies still actively pursuing both LCD and plasma?
That doesn't sound like much of a battle. In this war, choosing which technology is best for an application may be the easy part. Where things get trickier is in the market dynamics for large panels. For the purposes of this article, panels 30 inches and larger are considered large displays. I'll also address those specifically targeted to the professional AV and business markets and not consumer-oriented LCD TV and plasma TV products.
Although they are both flat-panel technologies, LCD and plasma monitors use two different approaches to creating images. One is emissive, producing its own light, and the other one requires a separate light source. Which is better? In many ways, the technologies themselves help answer a lot of the questions, and not surprisingly, each has strengths and weaknesses.
Plasma monitors trap a mixture of neon-based gas between two sheets of glass, dividing and compartmentalizing those mixtures into fixed pixel matrices. By applying electrical charges to those gases, plasma monitors generate ultraviolet light, which in turn excites the red, green, and blue phosphors, thus creating light and color. With those phosphors right below the protective glass, the viewer is effectively looking directly at the light source.
LCD panels also use a fixed matrix technology, but it's one with a great deal more flexibility in terms of size. Large LCDs use the same basic panel technology as much smaller desktop monitors and even, generally speaking, as LCD projectors, PDAs, and camera viewfinders. For plasma makers, however, it's both difficult and cost ineffective to reduce the physical size of the compartmentalized gas pixel matrix and thus impractical to build smaller plasmas. (Philips still offers a consumer 32-inch plasma, but Panasonic's 37-inch TH-37PW6UZ is the smallest business unit.) LCDs, too, have an inherent resolution advantage, because higher plasma resolutions would also mean squeezing the pixel matrix.
On the other hand, it is much easier for plasma makers to “get big.” LG, NEC, and Samsung offer 60-plus-inch pro-AV plasmas, and Samsung has even shown an 80-inch model, though it has not announced delivery. The limiting factor to increasing size is primarily in the ability to produce and cut the large panels of glass. For larger LCD panels, however, the obstacle is the increasing size of the backlight, which must shine through the Thin Film Transistor layer and color filters to produce brightness. Whereas LCD projectors, for example, can use a small, bright, and focused lamp, the backlight for a large panel must be as large as the panel itself. The challenge is evenly diffusing that backlight to eliminate bright and dim spots.
There are, of course, other strengths and weaknesses. For example, the direct-view phosphors in plasmas tend to do a better job accurately producing colors than LCD monitors, which shine light through a combination of color filters, trying to blend them to create accurate colors. The difference is particularly noticeable in side-by-side visual comparisons. Plasma also fares much better with moving images, thanks to faster drop-off and refresh rates than LCD, which still fights a reputation for ghosting in everything from video to computer games.
Which technology has better brightness and contrast is a little harder to pin down. A glance at the chart on p. 52 suggests that plasma is the clear winner in both, but the numbers simply don't tell the story. The different way each produces light makes comparisons awkward, and the competitive marketplace only makes it worse.
Plasma monitors, because they send electrical charges to each individual pixel, can send more electrical current to one pixel when not sending juice to all the other pixels. Thus plasmas will produce a brighter isolated spot on the screen than if the entire panel is lit. Conversely, the backlight of an LCD panel is always on, with the light either coming through or being hidden by twisted crystals. Thus LCD panels are as bright in one pixel as all the rest, whether the panel is partially or totally white.
Awkwardly, there is no clear industry standard for measuring and reporting plasma brightness, and that, not surprisingly, has led to exaggerated claims (see “Picture This: The Numbers Game” on p. 26). A few plasma companies — such as NEC, JVC, Panasonic, and Sony — ultimately refrain from getting caught in the fray and don't report brightness at all. Which technology is brighter overall ultimately depends heavily on what content is onscreen.
Contrast ratio is a little easier to rank. Plasma displays would probably win if all things were equal, but things are never equal. That's particularly true in higher ambient-light situations where LCD fares better than plasmas or CRTs, which both reflect far more light back toward the viewer.
It's generally understood, too, that LCD panels are more power efficient than plasmas, and that's true in most applications. Plasma monitors certainly use more power than similar-size LCD panels if both are brightly lit. However, it's easy enough to create scenarios where the opposite would be true, in which plasmas would be more efficient in “typical use” environments, where not all the scene is illuminated at one time.
THE BURN-IN QUESTION
When plasma monitors first appeared in the second half of the 1990s, they almost immediately captured public imagination. Big, cool, flat, and combined with rich images made for a technology that almost anyone would love to have. Of course, early plasmas had prohibitively high prices for most customers, businesses, and consumers, and adoption of the product has been slow and steady.
Yet plasma also has an overt weakness that has probably prevented the rapid growth in plasma sales, especially now as prices have approached more accessible levels. Plasmas suffer from burn-in, the physical change of the phosphors over time. It's a problem that can create the impression that these expensive pieces of equipment are disposable items. Burn-in is most noticeable when text and graphics are continuously displayed, such as the flight information on airport monitors. Ghosted characters begin to obscure current images, contrast is reduced, and color properties are altered. Although text is the worst, burn-in happens to all plasmas and pixels over time. However, with constantly moving video images, burn-in usually takes much longer to become noticeable and happens more evenly across the entire panel, making it much less obvious to the viewer.
In many ways, it's LCD's lack of burn-in that has driven the speculation that LCD will ultimately replace plasma. After all, a big, cool, and flat panel without burn-in surely captures the imagination even more, especially in a tried-and-true technology like desktop and notebook LCD. However, even the burn-in question isn't as obvious as it might seem. Today's plasmas last about twice as long as those of five years ago, thanks to improved phosphor technology. LG and Panasonic now believe they can double that again. What's more, LCD backlights fade over time, too.
It's not surprising that aside from the fast growth of smaller consumer-oriented LCD TV products, there's not much progress to report in the format war. More professional LCD monitors are coming, but not as fast as one might think. But it's not due to the aforementioned technical hurdles.
LCD manufacturers are now able to manufacture panels of 40 inches and above, and LG, NEC/Mitsubishi, and Samsung sell 40-inch pro-AV monitors. What's more, Sharp is expected to ship a 45-inch LCD-TV this summer, and Samsung has shown a 46-inch panel that is effectively ready to go. LCD manufacturers have also gone a long way toward improving both color accuracy and refresh rates. After all, LCD-TVs would not be successful if quality was a serious concern. Nor would Sony have started marketing LCD monitors in its LUMA series for professional video production if quality wasn't good enough for all but the most critical aesthetic judgments.
The lack of LCD products should be particularly surprising, given that it's that 40- to 50-inch size range that is the sweet spot for plasmas now and should be for public signage LCD products, as well. Nonetheless, the chart of professional AV oriented large flat panels lists twenty-three 42- and 43-inch plasmas and just five 40-inch LCDs.
Why? There are a couple of reasons, likely beginning but certainly not ending with price. Plasma holds a still-significant price advantage comparing 40-inch LCDs with 42-inch plasmas. However, here again the bottom line doesn't tell the whole story. The LCDs have a higher resolution and, thus, might arguably demand a premium. Decisions about which technology is better come down to application and availability.
Conventional wisdom suggests that plasma remains the appropriate solution for video-oriented applications, owing to the better color and smoother motion without ghosting, while LCD will likely begin to replace plasma in public signage installations, thanks to higher resolution, crisper text and graphics, and lower power usage. It's plasmas you'll see on the sets of newsrooms and late-night television shows and LCD that seems to be most appropriate for airports and hospitals where information trumps video in importance.
Over time those dynamics may change, particularly in light of the higher volumes, better economies of scale, and extra R&D dollars that LCD makers should be able to apply to increasing video performance and color reproduction. However, most companies are still pursuing both technologies, with Pioneer remaining the only maker solely committed to plasma and Sharp the only one completely focusing on LCD. That suggests that the markets have yet to become as clear as the technological differences, and those differences have advantages in different applications. It also suggests that LCDs' primary target, digital signage, has yet to take hold.
According to Insight Media, the digital signage market is poised to take off but is still in its infancy. Instead, it's the consumer market that is driving any large-scale adoption of flat-panel monitors, and that probably won't change. Many professional manufacturers, in both the video production and professional AV sectors, anticipate a boom in digital public signage; however, the numbers will almost certainly never match the huge volumes of the consumer electronics industry.
Rosemary Abowd of Pacific Media Associates puts it this way: “If a major airport makes a decision to overhaul its information displays with a few hundred new LCDs, that represents a good piece of business. But it's only one month or perhaps just a part of one month. For the huge LCD factories to start manufacturing larger LCD panels, they'd need to have one or two of those orders every month and probably on two or three continents each month, and there just aren't enough airports to go around.”
That's not to say that shopping malls, museums, other transit systems, churches, and entertainment venues won't join with those airports and produce those necessary volumes over time. Indeed, many in the industry anticipate that happening. But with manufacturers like Sharp and Samsung biding their time and releasing what would seem to be high-ticket, high-margin technologies, it's clear that they don't see a robust enough market yet.
What's more, LCD manufacturers have a business decision to make — whether to produce four 17-inch panels or one 46-inch. Currently, the 17-inch panels are money in the bank, especially given continuing supply shortage for those core desktop and notebook products. Those shortages will ease over time as new factories under construction become functional during the coming two years. But two years can be a long time in technology, and plasma manufacturers are continuing to strengthen their products.
Interestingly, plasma makers face much the same type of market decisions of supply, opportunity cost, and demand. Despite the hoopla over increasingly large panel sizes — LG Electronics has announced a 76-inch plasma for the consumer market and Samsung an 80-inch for the pro-AV market — the demand for 60-inch-plus panels isn't very strong.
The good news for the professional AV industry is that this potential format war, real or imagined, is driving both technologies forward. LCD may win in the end, as many have predicted, but for contractors who are buying and installing today, that end is a long way off. Better products today are what matters.
What's Out There (Model numbers may differ slightly based on color or accessories.)
|MSRP||Diagonal Size||Display Technology||Native Resolution||Brightness Spec||Contrast Ratio Spec|
|LG L3020T||$3,499.00||30||TFT LCD||1280×768||550 cd/m
|NEC LCD 3000||$4,299.00 ESP||30||TFT LCD||1280×768||450 cd/m
|Samsung SyncMaster 323T||$4,799.00||32||TFT LCD||1280×768||450 cd/m
|LG L3700||$6,999.00||37||TFT LCD||1366×768||600||600:1|
|Sharp LC-M3700||$7,995.00||37||TFT LCD||1366×768||430 cd/m
|Barco Solaris||$8,680.00||40||TFT LCD||1280×768||450 cd/m
|Christie FP40||$8,995.00||40||TFT LCD||1280×768||470 cd/m
|NEC LCD 4000||$5799.00 ESP||40||TFT LCD||1280×768||450 cd/m
|Samsung SyncMaster 403T||$7,999.00||40||TFT LCD||1280×768||500 cd/m
|Electrograph DTS4230||$3,795.00||42||plasma||852×480||780 cd/m
|Fujitsu P42VCA21UH||$4,999.00||42||plasma||852×480||700 cd/m
|Fujitsu P42HCA11WH||$5,999.00||42||plasma||1024×1024||1000 cd/m
|Hitachi CMP4203U||$7,995.99||42||plasma||1024×1024||1000 cd/m
|JVC GD-V422UA||$5,995.00||42||plasma||1024×768||1000 cd/m
|JVC GM-P420UG||$3,995.00||42||plasma||852×480||1000 cd/m
|LG L4200AT||$8,999.00||42||TFT LCD||1365×768||600||600:1|
|Philips 42FW997||42||plasma||1024×852||600 cd/m
|Planar Plasma PDP42BK||$2,999.00||42||plasma||852×480||1000 cd/m
|Planar Plasma PDP42HD||$3,999.00||42||plasma||1024×768||750 cd/m
|Samsung PPM42H3||$7,499.00||42||plasma||1024×768||1000 cd/m
|Samsung PPM42S3Q||$5,499.00||42||plasma||852×480||1000 cd/m
|ViewSonic VPW-4255||$5,499.00||42||plasma||1024×1024||1000 cd/m
|Pioneer PDP-433CMX||$12,995.00||43||plasma||1024×768||1000 cd/m
|BenQ PDP 46W1||$3,699.00||46||plasma||852×480||700 cd/m
|Fujitsu P50XCA11UH||$7,999.00||50||plasma||1366×768||600 cd/m
|Hitachi CMP5000WXU||$11,995.99||50||plasma||1280×768||340 cd/m
|Philips 50FW997||50||plasma||1366×768||600 cd/m
|Pioneer PDP-503CMX||$15,500.00||50||plasma||1280×768||900 cd/m
|Planar Plasma PDP50P||$7,499.00||50||plasma||1280×768||900 cd/m
|Samsung PPM50H3Q||$9,999.00||50||plasma||1366×768||1000 cd/m
|Hitachi 55HDM71||$9,995.99||55||plasma||1366×768||340 cd/m
|Samsung PPM63H3Q||$17,999.00||63||plasma||1366×768||1000 cd/m
For More Information
Christie Digital Systems
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