LED TVs are television sets whose display consists of an LCD with light-emitting diodes as a backlight, as opposed to other LCD TVs, which use fluorescent lamps for a backlight.
This is not to be confused with OLED display technology.
[edit] Introduction
Samsung first integrated LED backlights into the 40, 48, 52, and 57-inch versions of their LN-T81F series in 2007. Sony, in 2008, used LED backlighting for the 46 and 55-inch versions of their BRAVIA KDL-XBR8 series and introduced the first flat-panel moniter to use LED edge-lighting. In 2008 Sharp introduced the AQUOS LC-XS1US series, the first 52 and 65-inch HDTVs to use LED back-lighting. Samsung, in 2008, used LED-backliting for their A950 series. In 2009, Samsung introduced their "Luxia" series of LED edge-lit HDTVs, ranging from sizes of 32 to 55-inches. Vizio and LG have also announced their own LED-backlit HDTVs, scheduled to be released in 2009.
[edit] Technology
LED TVs use Light Emitting Diode (LED) backlights instead of the standard Cold Cathode Fluorescent Lamps used in most LCD televisions. LED TVs allow the manufacturer to build thinner housings making current LED TVs available in the market less than two inches thick. LED TVs are slightly more environmentally friendly than plasmas and conventional LCD TVs,[1] they use less power and use no mercury in their manufacture, however other elements such as gallium and arsenic are used in the manufacture of the LED emitters themselves.In general, the advantages of LEDs over fluorescent backlights are that they are small, low power, produce little heat, and are sometimes used in groups such that if one LED burns out, the remaining LEDs will still produce light. The long life and reliability increase of using multiple LEDs in signs is one reason they are increasingly being used in traffic lights. LED TVs usually produce deeper blacks and a higher overall color saturation, (since flourescent bulbs have a smaller optical frequency output range). LED TVs that use edge-lighting can be very thin [1]. Edge-lighting can result in a loss of screen uniformity compared to back-lighting.
LED TV sets use LEDs to produce the backlight for the image, which is still displayed on a conventional LCD. Without this backlight, the digitally-created LCD image would produce little or no light of its own (For example, calculators usually use a simple LCD screen without a backlight, and thus require an outside source of light to be seen clearly). The LEDs are placed along the outer edge of the LCD, projecting the light inwards without adding to the width of the screen. A light source on the outer rim of the TV makes it possible to regain space normally taken up by fluorescent light rods.
LED TVs may potentially also result in more environmentally friendly waste over normal LCD TVs (which contain Mercury Vapour in the Fluorescent bulbs that are used). Whilst the components of LEDs are generally more inert than Fluorescent bulbs, they do however still contain other toxic materials such as arsenic (Gallium Arsenide) and are not considered a much better long term solution to the problem of TV disposal.
