Friday, June 15, 2007

Think Global Act Local

Samsung has recently advertised some high-contrast LCD televisions, so I was getting curious if I should go for one of those rather than wait until one of the more exotic technologies to appear, or use it to avoid the drawbacks of my other favorite system, DLP.

LCD panels work by using a backlight and then using the liquid crystals to block off light from that panel. Unfortunately, they can't block light all that effectively, so a normal LCD panel will appear a dim gray rather than black when it is displaying a black scene. The high-contrast LCDs work by varying the intensity of the backlight. At the moment, the simplest thing to do is to use fairly standard technology, but change the brightness of the fluorescent tube that these panels use.

An alternative technology uses lots of white light-emitting diodes behind the LCD panel rather than fluorescent tubes. The LEDs can be brightened and dimmed in much more isolated regions than the fluorescent tube can, so that improves things even further. For instance, this makes it possible to have something very bright in one part of the screen and something very dim in another region. A TV using fluorescents would have to pick an intermediate backlight level, while this second type could have the LEDs at full brightness behind the bright part and at a very low level or even off behind the dark/black area.

It appears that Samsung has a dozen or so displays using the dimmed tube technology (which they call "dynamic contrast"), and a grand total of one using the LED backlight system (called "local dimming"). I haven't researched what other manufacturers have yet.

In the past, I've normally found Sony's HDTV video post-processing to be much more visually pleasing than that of Samsung, so that's a bit of a concern for me, but at this particular instant, I'm really interested in buying one of their sets...

Posted by mike at 04:25 PM | TV | Comments (0)