LED backlight makes LCD TVs shine

In This Article: Overview

LED backlight makes TVs shine

Samsung LN 55A950 (left) and Sony Bravia KDL-46XBR8

Our latest tests have turned up two LCD TVs with impressive black levels, the best we've seen from an LCD display.

The 55-inch Samsung LN55A950, $4,200, and the 46-inch Sony Bravia KDL-46XBR8, $5,000, rival plasma sets in their ability to display the deep, inky blacks that give images cinematic appeal.

Those two sets (along with models from Sharp and LG) are among a small but growing number of LCD sets that use backlighting from light-emitting diodes with local light dimming rather than conventional fluorescent lamps. Local dimming divides the screen into 128 segments that can be lighted or dimmed independently, minimizing light leaking into dark parts of an image. Manufacturers say LED backlight improves black levels as well as contrast and enables more even brightness, a wider range of colors, longer life, and better energy efficiency.

The Samsung and Sony TVs did well in all of those measures. They were among the best not only for black level but also for contrast, color, and brightness. The use of LEDs probably helped that performance, though some TVs with conventional fluorescent backlights had comparable scores for overall picture quality.

Our tests confirmed that they use less power than fluorescents. We measured the power used by the Sony KDL-46XBR8 and another 46-inch Sony that uses fluorescent backlights, the Sony KDL-46Z4100. Based on the national average cost for electricity, it shouldn't cost more than $44.33 per year to run the LED backlight model, compared with $64.42 for the other Sony.

Pricey for now

The downside to LED technology is cost. The Samsung and the Sony are very high-priced for their size. But prices for LED-backlighted models will probably drop, and the technology will trickle down to smaller sets over time. That's what has happened with 120Hz technology, which minimizes the motion blur in most LCDs. At first, only the biggest, premium-priced LCD sets used 120Hz technology, but about 25 percent of sets with 40-inch or larger screens now offer it. In our latest full Ratings of LCD sets, 23 models have 120Hz technology, and many of them are competitively priced for their screen size.

For all of their merits, the Samsung LN55A950 and Sony Bravia KDL-46XBR8 still fall short in viewing angle, an Achilles' heel for LCDs. They had noticeable degradation in picture quality when viewed from even a slight angle. But viewing angle isn't an insurmountable problem. Other LCD TVs have successfully addressed it, notably the Panasonic TC-37LZ800, TC-37LZ85, and TC-32LZ800. All three have virtually unlimited viewing angles that equal those of any plasma TV.