Plasma TV vs. LCD
By Jack Burden, Senior Reviewer
This is a complicated topic: when choosing between LCD and plasma TVs, you're actually selecting between two competing technologies, both of which achieve similar features (i.e., bright, crystal-clear images, super color saturated pictures) and come in similar packages (i.e., 3.5 to 5 inch depth flat screen casing). To complicate the decision-making process further, price and size are two previous considerations that are rapidly becoming non-issues as LCDs are now being made in larger sizes and at competing prices with plasma TVs.
Despite all these similarities, these technologies differ in how they process and display incoming video/computer signals.
Plasma flat screen technology consists of hundreds of thousands of individual pixel cells, which allow electric pulses (stemming from electrodes) to excite rare natural gases-usually xenon and neon-causing them to glow and produce light. This light illuminates the proper balance of red, green, or blue phosphors contained in each cell to display the proper color sequence from the light. Each pixel cell is essentially an individual microscopic florescent light bulb, receiving instruction from software contained on the rear electrostatic silicon board. Look very closely at a plasma TV and you can actually see the individual pixel cell coloration of red, green, and blue bars. You can also see the black ribs which separate each.
Whether spread across a flat-panel screen or placed in the heart of a projector, all LCD displays come from the same technological background. A matrix of thin-film transistors (TFTs) supplies voltage to liquid-crystal-filled cells sandwiched between two sheets of glass. When hit with an electrical charge, the crystals untwist to an exact degree to filter white light generated by a lamp behind the screen (for flat-panel TVs) or one projecting through a small LCD chip (for projection TVs). LCD monitors reproduce colors through a process of subtraction: They block out particular color wavelengths from the spectrum of white light until they're left with just the right color. And, it's the intensity of light permitted to pass through this liquid-crystal matrix that enables LCD televisions to display images chock-full of colors-or gradations of them. LED TVs are a new form of LCD Television.
As the advantages show, plasma technology has the better picture quality in normal to low room lighting conditions and are better in 4 out of 5 picture quality categories. Plasma technology will almost without exception triumph during night time viewing. LCD televisions are great for sunroom/breakfast room type environments. Also, LCD monitors are generally better for public display such as airport signage and retail store signage due to the bright room light environment. See full article on plasma vs. LCD picture quality.
LCD monitors display static images from computer or VGA sources extremely well, with full color detail, no flicker, and no screen burn-in. Moreover, the number of pixels per square inch on an LCD display is typically higher than other display technologies, so LCD monitors are especially good at displaying large amounts of data - like you would find on an Excel spreadsheet for example - with exceptional clarity and precision. LCDs are also available in many more sizes, especially the smaller sizes most often used for a computer display.
Plasma technology has increased anti burn in tactics as well as computer and static signal handling. There are still issues with each depending very much on the model and manufacturer. For example, 720p plasma televisions do not handle a computer input well and product a very jaggy image on plasma's larger sizes.
FAST-MOVING VIDEO PLAYBACK
Plasma displays get the nod here because of their excellent performance with fast-moving images and high contrast levels. There are still some 2nd tier manufacturers whose plasma product displays some phosphor lag, a dragging from brights to darks.
While the "response time" of LCD TVs has markedly improved in the last couple of years, especially with the advent of 120/240Hz displays they still suffer from a motion blur effect, where the individual pixels are just slightly out of step with the image on the screen. The high refrash rate LCD televisions can also have some undesireable effects on the picture. During fast moving sports scenes, the most discerning eyes can detect this slight motion response lag.
There is a reason LCD panels are the preferred visual display units for use on airplanes: LCDs aren't affected by increases or decreases in air pressure. Their performance is consistent regardless of the altitude at which they're utilized.
This is not the case for a plasma TV. The display element in plasma TVs is actually a glass substrate envelope with rare natural gases compressed therein. So, at high altitudes (6,500 feet and above), an air-pressure differential emerges, which causes plasma displays to emit a buzzing sound due to the lower air pressure. This noise can sound rather like the humming of an old neon sign. NEC has been effective in producing several plasma models that are rated to 9,500 feet.
ADVANTAGE: LCD, at 6500 feet and higher.
LCD manufacturers claim that their displays last, on average, 100,000 hours. In fact, an LCD TV will last as long as its backlight does - and those bulbs can sometimes be replaced! Since this is nothing more than light passing through a prismatic substrate, there is essentially nothing to wear out in an LCD monitor. However, one nasty little known fact about LCD technology is that as the backlight ages it can change colors slightly (think of florescent office lighting). When this occurs the white balance of the entire LCD will be thrown for a loop and the user will need to re-calibrate, or worse, try to replace the backlighting or ditch the unit altogether. Some of the early purchasers of larger LCD screens will be learning this tidbit in a couple of years. One thing that I’ve found in this industry, it is not easy to find out whether the backlighting on LCDs can be replaced. Manufacturers are either hesitant to discuss the topic, or they just don’t know.
Plasma, on the other hand, utilizes slight electric currents to excite a combination of noble gases (i.e., argon, neon, xenon), which glow red, blue, and/or green. This is an essentially active phenomenon, so the phosphoric elements in plasma displays fade over time. Many manufacturers state a new half life of 100,000 hours, that's just over 68 years if the TV is on 4 hours every day. While I am skeptical of this spec, I do believe strides have been made to nearly even the playing field with LCD. At half life, the phosphors in a plasma screen will glow half as brightly as they did when the set was new. There is no way to replace these gases; the display simply continues to grow dimmer with use.
ADVANTAGE: Even depending upon manufacturer quality.
SCREEN BURN IN
LCD technology is not prone to screen "burn-in" or "ghosting" (premature aging of pixel cells) due to the nature of the technologies "twisting crystals."
With plasma displays, static images will begin to "burn-in," or permanently etch the color being displayed into the glass display element. The time it takes for this to occur depends greatly on the anti burn-in technology of the manufacturer. Recent improvements by plasma manufacturers have certainly extended the time it takes to burn in a plasma pixel cell. In the past I was concerned to place a DVD on pause 15 minutes. Now, many of the enhancements such as better green phosphor material, and motion adaptive anti burn-in technology are greatly reducing the risk of burn in. It’s gotten so much better that I don’t even worry about it anymore. In a new model plasma from any top tier manufacturer I would put "ghosting" estimates at an hour or more now (Ghosting can be "washed" out by displaying static gray material). Permanent burn-in I would put at more than 10 hours.
ADVANTAGE: LCD, but not as much of a concern as a year ago.
PRODUCTION SIZE & COST
All television measurements are stated in inches as a diagonal measurement of the display screen from corner to corner.
Both LCD and Plasma televisions are becoming more readily available in larger sizes though plasma still leads the size battle by a great margin. Pioneer and LG produce 61" plasma sizes while Panasonic has a readily available 65" model. Though it is not being imported into the U.S. yet, PanasonicSamsung has produced a gigantic plasma television of 150 inches. Though such mammoth monitors are expensive, they exhibit none of the "kinks" one might expect with such large displays. In other words, even the largest plasma displays are reliable. Large plasma displays will consume power – try 675 watts for a 65" display compared to around 330 watts for a 42" plasma although plasma manufacturers have reduced power intake and made the product more efficient, some even qualify for an energy star rating now.
ADVANTAGE: Plasma. Even though production costs and retail prices have come down for both technologies, plasma still has the edge as far as production cost and capacity go.
Not a very important issue but worth noting. Because LCDs use florescent backlighting to produce images, they require substantially less power to operate than plasma TVs do. LCD displays consume about half the power that plasma displays consume. The reason: Plasmas use a lot of electricity to light each and every pixel you see on a screen - even the dark ones. Though plasma manufacturers have improved voltage consumption requirements a plasma TV will consume around a third more power for the same size display.
Price and Value
Plasma TVs have generally enjoyed lower pricing per size vs. LCD TVs. While LCDs have nearly caught up with plasma in the 42" size, plasma still dominates in the larger size ranges. When comparing comparable Tier 1 Quality LCD with Tier 1 Plasma, the larger the size, the more the price savings by purchasing plasma. In the 46" size range a plasma currently sells for a 30% to 40% discount, while a 58" plasma may yield between 40% to 50% discount savings. Resolution is no longer an issue due to the fact that most all TVs 46" and larger are full HD 1920 X 1080 (1080p) resolution.
Our value ratings continue to be reason that plasma TVs generally receive higher marks in our overall TV ratings. See the full Comparison Ratings Chart here.
ADVANTAGE: Plasma, especially in larger size TVs.
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