The 21st century has been marked by incredible advancement in information technology. One of the technologies that is continually evolving is display technology like televisions. As of 2011, high-definition televisions have rapidly become the standard, with flat-screens replacing the age-old cathode ray tube technology that had been a mainstay in television monitors. Consumers looking to upgrade to the latest in HD technology will find they have three distinct choices: LCD, plasma and LED. Each technology is different, and may fit your needs better than another.
One of the fundamental differences between LCD, plasma and LED TVs is the technology behind their operation. TVs using liquid crystal display have a liquid crystal between the display panel on the TV. This crystal activates when supplied with an electrical current, producing the picture. LCD screens are backlit using cold cathode fluorescent lamps. LED TVs work use the same type LCD technology, however backlighting is provided by light-emitting diode lights. Plasma is based on an entirely different technology, with a sheet of plasma cells between the display panel. These cells activate and produce the picture as electricity is passed through them.
Contrast ratio refers to the ability of the TV to show high contrast areas on the screen, principally the brightest (white areas) and the darkest (black areas). A TV with a high contrast ratio will show a considerable difference between the lighter and darker areas of the screen. Plasma TVs fare the best in this department, as each individual plasma cell can darken appropriately in dark areas, and even turn themselves off in the darkest areas. By contrast, the CCFL backlighting in an LCD screen can only dim in some areas, resulting in less depth in dark areas of the picture. The LED screen comes in somewhere in the middle, with the individual LED lights being able to dim and even turn to an off position on dark parts of the screen. This results in a better contrast ratio than LCD, but still not quite as effective as in plasma.
When viewed from an angle, plasma TVs retain a fairly clear, sharp image. LCD screens, however, often lose colour and detail when viewed at an angle. The LED screen suffers a similar problem, but the decentralised backlighting provided by the LED lights helps to minimise the losses except for at the most extreme angles.
Moving images can be taxing on an HDTV's picture, and for a long time plasma screens have still held an edge as each cell can refresh at a faster rate than the entire LCD screen, which lags behind somewhat. However, LCD technology continues to improve and this lag is beginning to minimise, and may eventually be overcome entirely. These changes will improve the quality of moving images on an LED TV as well.
By far, the most energy efficient of the three categories is the LED TV. Plasma TVs consume large quantities of power to light each and every sub-pixel on the screen. The CCFL backlighting on the LCD requires much less power to light up and produce a picture. However, LED lights are extremely energy efficient and require far less electricity to light up than both LCD and plasma.
Plasma screens are notorious for having a shorter lifespan than their LCD counterparts. The brightness output by the plasma screen, coupled with the considerable energy demands, mean that the machine undergoes considerable stress. Plasma screens are also more susceptible to screen burn-in compared to LCD and LED screens. The LCD and LED screens generally will last as long as their backlighting remains functional.
One of the biggest points most consumers will consider is the cost of purchasing a TV. For many years, plasma screens have reigned as the least expensive choice due to extensive production sizes and demand. However, as LCD production continues to expand, prices continue to lower to more competitive rates with the plasma screen. As a relatively new technology in 2011, prices on LED screens continue to remain high due to lower production numbers. As demand and production numbers continue to increase, costs on the LED screens will eventually lower.
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