The variations of LED backlighting offer different benefits. The first commercial full array LED backlit LCD TV was the Sony Qualia 005 introduced in 2004, which used RGB LED arrays to produce a color gamut around twice that of a conventional CCFL LCD television, possible because red, green and blue LEDs have very sharp spectral peaks which, combined with the LCD panel filters, results in significantly less bleed-though to adjacent color channels. In this way the unwanted bleed-through channels do not "whiten" the desired color as much, resulting in a larger gamut. RGB LED technology continues to be used on selected Sony BRAVIA LCD models.
LED backlighting employing so-called "white" LEDs produces a broader spectrum source feeding the individual LCD panel filters that is more similar to CCFL sources, and hence results in a more limited display gamut than RGB LEDs, but at lower cost.
Dynamic 'local dimming' LED TV was first demonstrated by BrightSide Technologies in 2003[9] and later commercially introduced for professional markets such as video post-production [10].
Edge-LED lighting was first introduced by Sony in September 2008 on the 40 inch BRAVIA KLV-40ZX1M (referred to as the ZX1 in Europe). Edge-LED lighting for LCD televisions allows thinner housings; the Sony BRAVIA KLV-40ZX1M is 1 cm thick; others are also extremely thin. The 55" Samsung LED8000 Smart TV has a 0.2" (5mm) bezel.[11]
LED-backlit LCD TVs are claimed to have longer life and better energy efficiency than plasma and CCFL LCD TVs.[12] Unlike CCFL backlights, LEDs use no mercury, an environmental pollutant, in their manufacture. However, other elements such as gallium and arsenic are used in the manufacture of the LED emitters themselves; there is some debate over whether they are a better long-term solution to the problem of TV disposal.
Because LEDs can be switched on and off faster than CCFL displays and can offer a higher light output, it is theoretically possible to offer very high contrast ratios. They can produce deep blacks (LEDs off) and high brightness (LEDs on). However, measurements made from pure black and pure white outputs are complicated by the fact that Edge-LED lighting does not allow these outputs to be reproduced simultaneously on-screen[clarification needed].