LED Backlighting,A Better Black

Decisions, Decisions! You want the ultimate flat panel HDTV; do you go with Plasma or LCD? If you go with Plasma you get faster refresh rates, so the set will perform better when you watch sports or action movies; and you get better color detail in dark scenes, due to better native contrast levels. It will cost about 40% more in electricity than an LCD to run it, and you will need to move the TV to the basement, change the lighting system, and install dimmers to get the optimum performance from your Plasma HDTV (you don’t want ambient light to reduce your contrast levels or throw glare back at you off the glass front). If you go with LCD, you don’t have to put the HDTV in the basement, so you don’t have to spend the money to redo the lighting, or take the 40% hit on your hydro bill. Sports and action movies won’t look as good as with Plasma... Oh wait; they fixed that with 120Hz refresh technology. But then there is the black level issue. Enter the Samsung 81 series LCD to address this short- coming of LCD HDTV technology.

The Samsung 81 series LCD (LN-T 4081, LN-T4681, LN-T5281 and LN-T5781), has all of the features you would expect in a top-of-the-line flat Panel LCD display (120hz refresh, good speaker system, lots of connectivity, etc). What sets these HDTV apart from other top-of-the-line LCD models is the ability to produce black and contrast levels that rival Plasma displays. The sets feature a new LED based backlighting system, which produces dynamic contrast levels of 500,000:1, according to Samsung. Certainly when you compare these sets to other top-of-the-line LCD HDTVs, you will see an appreciable difference in contrast levels, and color depth in dark lit scenes.

Conventional LCDs use a single florescent backlight as the light source. Sets in the Samsung 81 series divide the backlight source into sections, so instead of one backlight, the 46 inch LN-T4671 has 64 backlight sections. Each section contains its own white LED, which can be brightened and dimmed independently. The ability to perform localized dimming provides these sets with better dark scene performance than other LCD sets on the market. Conventional LCDs have to turn the backlight brightness up enough to display the brightest area of the scene, and then use LCD panels to block that backlight in the remaining darker areas of the scene. With the 81 series, backlight brightness increases only for the section(s) where the scene is bright. In sections with darker scenery the backlight brightness decreases to achieve the desired effect. Not quite the pixel level control of Plasma HDTV, but a significant improvement over the standard backlighting technology. Independent control of the LED intensity, also allows the set to use less energy that conventional LCD HDTV.

With the use of LED lighting in DLP HDTVs, and now their introduction as the backlighting source for LCD HDTVs, LED based HDTV are poised to be the next wave of mainstream shinny new flat panel HDTVs. In labs around the world work is being finalized on more LED technology, specifically OLED (Organic Light Emitting Diode), which is being touted as the “Holy Grail” of Flat Panel HDTV.