Sony KDL55EX621 55" Class LED Backlit HDTV - 1080p, 16:9, 120Hz, Internet Widgets, Energy Star (Refurbished)Item#: S192-5518 RB  |  Model#: RB-KDL55EX621

What Is An LED HDTV?

An LED-backlight LCD television is an LCD TV that uses LED backlighting instead of the CCFLs used in traditional LCD televisions. It is not a true LED display but is called "LED TV" by some manufacturers. The use of LED backlighting has a dramatic impact, resulting in a thinner panel, less power consumption and heat dissipation, and a brighter display with better contrast levels.

The LEDs can come in three forms:

• Dynamic RGB LEDs which are positioned behind the panel
• White Edge-LEDs positioned around the rim of the screen using a special diffusion panel to spread the light evenly behind the screen (the most common)
• A full-array of LEDS which are arranged behind the screen but are incapable of dimming or brightening individually

LED backlighting techniques:

An LED-backlit TV:  RGB dynamic LEDs This method of backlighting allows dimming to occur in locally specific areas of darkness on the screen. This can show truer blacks, whites and PRs at much higher dynamic contrast ratios, at the cost of less detail in small bright objects on a dark background, such as star fields.

Edge-LEDs:  This method of backlighting allows for LED-backlit TVs to become extremely thin. The light is diffused across the screen by a special panel which produces a uniform color range across the screen.

Full Array LEDs:  Many brands use LED backlighting technology and may offer a range of benefits over CCFL LCD TVs such as reduced energy consumption, better contrast and brightness, greater colour range, more rapid response to changes in scene and a capacity to provide the means to render an image more accurately.

Differences between LED-backlit and CCFL-backlit LCD displays

LED-backlit LCD TVs differ from conventional CCFL-backlit LCD TVs in the following: 

• Produce images with greater dynamic contrast.
• With Edge-LED lighting they can be extremely slim. Models on the market can be approximately one inch thick.
• Offer a wider color gamut, especially when RGB-LED backlighting is used.
• Less environmental pollution on disposal.
• Generally 20-30% lower power consumption.