Monday, July 25, 2005

Flickering light prevents TV image smearing

Smearing, also known as ghosting, is a problem in thin liquid crystal display (LCD) televisions because the tiny pixels that create the image take time to switch on and off.

The problem, widely recognized as the main drawback of LCD TVs, is apparent in fast moving objects such as tennis balls, but even slower moving images get fuzzy around the edges.

Old-fashioned tube TV screens have no such issue, because they light up 50, 60 or 100 times per second for just a split second -- much shorter than the time to light up a flat screen pixel -- with large inactive or dark periods in between. The viewer is not conscious of the dark periods and combines the flashes to a seamless moving image.

Philips has combined an LCD screen with an idea from a CRT, a fast refresh rate based on turning the backlight on and off. The new technique is supposed to help eliminate image "smearing" and give a sharper picture. They say they will have a television on the market soon in 2006 with this tech.