Thursday, July 16, 2009

LED vs LCD

LED TVs are technically a member of the LCD TV family. The display screen on a LED is a liquid crystal display the same as it is on any other LCD TV. The main difference between the two lies with different backlighting techniques which may change the picture quality characteristics dramatically.

Traditional LCDs have used some form of flourescent lighting from tubes to much more advanced flat arrays of lights. LED TVs use Light Emitting Diodes to light the LCD panel. Just as there are different styles of flourescent lights in traditional LCDs there are also different styles of LED backlighting. There are LED TVs like the Sony KDL-55xBR8 that have a panel of LED lights behind the LCD panel. In the Sony the LEDs are tri-colored and can be controlled in banks for an effect called "local dimming". This allows darker areas of the picture to have the backlighting dimmed behind them resulting in better contrast and black levels. In the Luxia line of Samsung LED TVs, the LED lights are surrounding the edge of the panel and this arrangement allows for the very slim depth of those models. Without the ability to do local dimming these are functionally similar to traditional LCDs so in this article we will be comparing local dimming LED TV to traditional LCD TV.

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