LED-backlit LCD

An LED-backlit LCD is a flat panel display which uses LED backlighting instead of the cold cathode fluorescent (CCFL) backlighting used by most other LCDs. LED-backlit LCD TVs use the same TFT LCD (Thin-film-transistor liquid-crystal display) technologies as CCFL-backlit LCD TVs. Picture quality is primarily based on TFT LCD technology, independent of backlight type. While not an LED display, a television using this display is called an “LED TV” by some manufacturers and suppliers. In the UK, the Advertising Standards Authority has made it clear in correspondence that it does not object to the use of the term “LED TV”, but requires it to be explained in advertising.

Three types of LED may be used:

The iPhone 5 has an LED-backlit TFT IPS LCD, while the Sony Xperia S is an example of an LED-backlit TFT TN LCD (also referred as TFT LCD).

Many brands use LED backlighting technology, which offer the advantages over CCFL LCDs of reduced energy consumption, better contrast and brightness, greater color range, more rapid response to changes in scene and more accurate image rendering.

This method of backlighting allows local dimming of specific areas of darkness on the screen. This type of display comes in white or the more expensive RGB LED configuration. This can show truer blacks, whites, proper color saturation (on RGB LEDs), and photorefractive effects at much higher dynamic-contrast ratios by dimming (or brightening) the backlight locally (at the cost of less detail in small, bright objects on a dark background, such as star fields or shadow details).

Compared to CCFL-backlit LCDs, LED-backlit LCDs:

LED-backlit LCDs are not self-illuminating (unlike pure-LED systems). There are several methods of backlighting an LCD panel using LEDs, including the use of either white or RGB (Red, Green, and Blue) LED arrays behind the panel and edge-LED lighting (which uses white LEDs around the inside frame of the TV and a light-diffusion panel to spread the light evenly behind the LCD panel). Variations in 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 about twice that of a conventional CCFL LCD television. This was possible because red, green and blue LEDs have sharp spectral peaks which (combined with the LCD panel filters) result in significantly less bleed-through to adjacent color channels. 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 Sony BRAVIA LCD models.

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