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Liquid-crystal display (LCD) televisions vary in size from nearly two inches to 90 inches. They tend to be thinner and lighter than the cathode ray tube (CRTs) of similar display size and use LCD display technology to generate images. LCDs are fast displacing their major competitors the plasma display panel (plasma) and rear-projection television in the large-screen market.
An LED-backlit LCD TV is a flat panel display that uses LED backlighting as their source of light rather than the cold cathode fluorescent (CCFL) and therefore tend to perform a little differently. They however use the same TFT LCD (thin film transistor liquid crystal display) technologies as CCFL-backlit LCD TVs. A large number of electronic companies often tout them as the higher-end models. Their most common features include a 120 and 240 Hz refresh rates essential for reduction of the blurring motions common with LCDs.
A plasma display panel (PDP), or just plasmas, use flat screen technology -- consisting of hundreds of thousands of individual pixels that stem from electrodes to excite rare natural gases (usually xenon and neon) causing them to glow and produce light. The resulting light illuminates a proper balance of green, red or blue phosphors found in each cell, ultimately displaying suitable color sequence. Essentially, each pixel is an individual microscopic florescent light bulb that is instructed by software found on the rear electrostatic silicon board.
Light output
LED LCDs are the brightest TVs in the market. Certain models are capable of nearly 100 footlamberts. Plasmas are however less bright although they are way brighter than traditional CRT tube TVs. In a dusky room, 100 footlamberts will be penetratingly bright and can cause eye fatigue. In a bright room however, such as during daylight, they offer poor visibility.
When it comes to anti-glare or anti-reflective material on each screen, a plasma that has a good anti-reflective coating may provide a better view within a lit room than a glossy-screen LCD that lacks the coasting -- and vice versa.
If you have a well-lit room or watch a lot of TV during the day, the LED LCD is probably your ultimate choice and if you are a night-watcher and looks to have your TV disappear into the background, then plasma is your pick.
Black level
Plasmas offer the best black levels while the LED LCDs can often have an absolute black. However, when watching a movie, plasmas may seem a little darker.
Contrast ratio
Contrast ratio, described as the ratio between the brightest and the darkest part, is an essential feature in the broad-spectrum of a TV set picture quality. A display that has a high contrast seems more realistic and has more virtual depth. Exceptions do however exist. The Sharp’s Elite LED LCD has an advanced local dimming backlight that gives it a plasma-like contrast ratio. Sony's HX950 series also has local dimming although it hasn't received as much praise as the Elite. LG's 55LM9600 on the other end is even less so.
A good LED LCD doesn’t however make them all good. It also doesn’t signal a new generation of better LED LCDs. Sharp’s Elite doesn’t add anything new as it is a local dimming LED LCD, which tends to be more expensive than edge-lit models -- and even much more pricey than plasmas, at the same size.
Some incredibly thinner technologies, such as OLED, (organic light-emitting diodes), FED and SED are however coming down the pike promising better contrast ratios, picture quality and ultra-efficiency. None of these has entered widespread production at present. No doubt, the three may be the most noteworthy advancement in TV technology in decades and an immeasurable improvement over the LCD and plasma. At this year's CES, LG and Samsung revealed potential OLED models with the LG winning CNET's Best of CES Award.
Viewing angle
LCDs tend to lose picture quality when viewed “off axis” as compared to directly at the front of the screen. In-plane switching LCDs do however offer a better viewing angle at the expense of contrast ratio and black level.
Energy consumption
LED LCDs prove to have the lowest energy consumption, more so when the backlight is toned down. CCFL LCDs offer almost similar addendum. When the contrast control is turned up, plasmas are often less energy efficient. If looking to go green however, an LED LCD could be your utmost option though it is less likely to prove an ultimate money-saver as they are the most expensive.
Cost
Cold cathode fluorescent lamps (CCFLs) LCDs are the cheapest TVs of the triad as they tend to be rated at the lower-end of TV offerings. Plasmas do have the best size over prize ratio and in some cases can cost half as much as big LED LCDs based on per-screen-inch.
Lifespan
Plasmas are almost the only technology that lists lifespan -- often claimed as 100,000 hours. The fluorescent lamps in CCFL-based LCDs age just like any other florescent lamp and are often rated for 30,000 to 60,000 hours. The "white" LEDs used in LED LCDs will also dim over time. There is however little published data on LED lifespan although it is assumed to be similar to CCFLs.
Rapid motion video playback
Plasma offer excellent response when it comes to fast-moving video playback given their fast moving images and high contrast levels. LCDs’ performances do suffer from blur effects – where individual pixels fail to synchronize with the images on the screen. Their response time however improved significantly in the last couple of years after the introduction of 120Hz and 240Hz displays. Their high refresh rates also cause some undesirable effects on the picture quality, for instance during fast moving movie or sports scenes, the slight motion response lag can be noted.
Uniformity
When considering consistent brightness, or uniformity, of image, plasmas are known to have issues although they are less frequent and noticeable. Edge-lit LED LCDs are the worst culprits of the three. Cheap CCFL LCDs and backlit LED LCDs do often also have their own issues. In a number of cases, the uniformity varies per case, meaning your TV may seem fine although some other user may hate the one he bought of a similar model.
