 |
| For video viewing, “having blacker blacks is important,” says Samsung’s Ian Miller. “LCDs are better than plasma in doing that.” |
 |
| “Plasma still has the size advantage in Fortune-1000 boardrooms,” says NEC’s Keith Yanke. |
According to Keith Yanke, senior product specialist for plasma for NEC Solutions America, the heat generated by plasma displays is becoming less of an issue “as panel fabrication becomes more efficient.” He says some plasma monitors now can use “variable speed fans that stay off until a certain temperature is reached.”
[an error occurred while processing this directive]
While plasma’s noise levels are beginning to decrease, Miller says plasma’s hefty power requirements aren’t likely to change. “Typically with plasma, you’re switching 200 to 300 volts, and you’re switching it very fast,” he explains. “In LCDs, you’re switching 5 to 12 volts. That’s a very big difference.” The heat and voltage requirements directly affect the size of the cabinet and its internal electronics. “The electronics that drive an LCD weigh a small fraction of the electronics needed to drive a plasma, partly because of the high power and high heat dissipation.”
Apples to Oranges
Other comparisons stem directly from the fact that these are radically different display technologies. Plasma is a phosphor-based device, while LCD is a transmissive device.
 |
| Since plasmas are subject to burn-in, an LCD is often a better bet for long-term installations, says Philips’ |
Plasma bumps up against the opposite wall, partly as a consequence of its fast switching. “Plasma inherently has no gray scale,” says Miller. “It’s either on, or it’s off. To get intermediate shades of gray, you have to use time-division techniques. Instead of turning a pixel on for a full period of time, you turn it on for half a period, and you get half brightness, which our eyes integrate over that time and average out.” If the plasma manufacturer slows down the switching too much, there can be a noticeable strobing.
“Only the most sensitive people will see the [strobing] effects,” Miller explains. “Obviously, the more often you switch things, the more power you use. So there’s a trade-off here.”
Technology differences also affect the rate at which costs go down. “Plasma uses tiny little light bulbs, as opposed to LCD which uses tiny little transistors,” says Chris Connery, director of product line management for NEC-Mitsubishi Electronics Display. “We can make transistors very, very small. The industry has a very good expertise in doing that, from microprocessors and now LCD technology. But it’s more difficult to make very, very small light bulbs.” Because of this difference, LCD prices are likely to fall faster than plasma prices. Over time, LCD screens could drop to the same price—or even become less expensive—than same-size plasma screens.
 |
| “A 30-inch LCD can have a native resolution of 1,280 by 768,” says NEC-Mitsubishi’s Chris Connery. The same size plasma can’t. |
Eye Candy
For some monitor buyers, image quality is job one. Here, plasma and LCDs offer a mix of plusses and minuses. “Plasmas tend to have a higher contrast than LCDs,” says Yanke. “Our 40MP3 has a 1,500:1 contrast ratio. LCDs are hovering somewhere around 400:1.” Plasma also has advantages in the purity and distribution of the colors. “From corner to corner, plasma is more even, as far as brightness and color uniformity goes,” Yanke explains. “With LCDs, that can vary a little bit due to the transmissive nature of the light going through the LCD and the different depths or diameters of the LCD panel itself.” If the LCD backlights are improperly mounted, they can contribute to an unevenness of the brightness levels and to a drop-off of color saturation in some areas of the display.
LCD takes the honors for having the blackest blacks, according to Miller. When you look at a plasma screen, “you’re really looking at the phosphors, and phosphors reflect light,” he says. “The ambient light hits the phosphors, and although the phosphors aren’t being excited, they’re still relatively good reflectors of ambient light. Our eyes see that as a mid-to-darkish gray, but certainly not as black.” Miller says that new vertically aligned technology, such as PVA (Patterned Vertical Alignment), can produce LCD screens “where the black actually is black.”
Whether blacker blacks are essential may depend on your application for the monitor. “If you want good video viewing or good game viewing, having blacker blacks is quite important,” says Miller. “LCDs are intrinsically better than plasma in doing that. Plasma could improve by putting selective filters on the front, but that will impact the power, because not only are you going to filter out the ambient light, but that will lose some of the transmitted light, as well. So there’s a trade-off. It’s an area where there will always be a trade-off.”
[an error occurred while processing this directive]
