How Does an LED-Backlit LCD Work?

A liquid crystal display (LCD) television that is backlit with light-emitting diode (LED) technology is designed to produce a more brilliant picture than standard LCD high-definition televisions. In particular, LED-backlit LCD televisions are intended to compete with more high-end plasma displays.

Background

Standard LCD televisions use fluorescent tubes to illuminate the screen, a technology known as CCFL. These tubes must always be on, which means that when a section of the image is supposed to be black, some light creeps into the picture and reduces the image sharpness. In addition, according to "The New York Times," fluorescent tubes offer limited color saturation.

LED Technology

An LED-backlit television uses LEDs to light the screen, either having the LEDs placed in the back of the display or on the side. When an image is supposed to be black, the LEDs can shut off completely, increasing the image sharpness. A typical TV of this kind has about 1,000 LEDs.

Considerations

According to CNET, the LED-lit displays with the highest quality picture use full-array backlighting with local dimming, in which the LEDs are installed in the rear of the display.

References

• CNET Reviews: LED TVs Compared: Local Dimming, Edge-Lit, and Full Array
• "The New York Times": What's an LED TV?
• ZDNet: Westinghouse Announces New Slate of LED-Backlit LCD HDTVs, Including 42-Inch Set for Just $799