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LCD
clarity: A penny spent for a millisecond saved
by May Wongap - Associated Press
SAN JOSE, Calif. - Unless you're an Olympic athlete, milliseconds
should hardly make a difference in your life.
Why then, are LCD computer monitors and LCD televisions boasting
a millisecond response feature in their sometimes confusing
laundry list of specifications?
"It's the spec du jour," said Chris Connery, a vice
president at DisplaySearch, a unit of market research firm
NPD Group.
At a Best Buy store in Palo Alto, every LCD computer display
listed millisecond response times at the top of its product
placard, above other key features such as contrast ratio,
resolution and brightness.
Technically, the fraction of a second description refers to
the length of time it takes for the pixels within the liquid
crystal display to turn on or off to display an image. For
consumers, it boils down to how much blurring might occur
when viewing fast motion video in sports, movies or video
games.
It's simple. The faster the response, the sharper the picture.
Or is it? Technological improvements in recent years have
reduced response times to the point at which performance gaps
between products would be hard to notice, experts say.
The
industry norm dropped from 25 milliseconds three years ago
to about 8 milliseconds for LCD computer monitors and 16 milliseconds
for LCD TVs by the end of 2005. This year, some desktop monitors
have reached as fast as 2 milliseconds. For LCD TVs, 8 milliseconds
is emerging as the new norm. |
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"Most
consumers wouldn't be able to tell whether the display is 12 milliseconds
or 1 millisecond," Connery said.
Samsung Electronics Co. and ViewSonic Corp., two companies leading
the way on response times, even acknowledge that new breakthroughs
would likely be undetectable to the eye. In fact, a 16 millisecond
response time translates roughly to 60 frames per second-the rate
of fluid, full motion video-and thus theoretically eliminates obvious
blurring. But some manufacturers and experts contend a difference,
and slight blurring, can still be perceived between 8 milliseconds
and 16 milliseconds.
"You're definitely getting a better image on the screen, less
lag time and just a better experience, especially for fast action
movies or sports," said Ali Atash, a senior product manager
for LCD TVs at Samsung.
Below 8 milliseconds, any difference in quality would be more difficult
to see, with the exception of video gamers dealing with intense
motion, according to Erik Willey, a senior product manager at ViewSonic.
Still, electronics companies are competing as if a gold medal were
at stake. It's partly for bragging rights, and partly a piece of
the larger marketing battle against plasma TVs and to win over holdouts
of cathode ray tube monitors.
"We consider response time as the last frontier in terms of
screen performance," Willey said.
ViewSonic was the first to debut a 2 millisecond desktop and has
promised to soon unveil a 1 millisecond model.
Blurring due to motion in video is an inherent drawback of LCD displays-an
effect that doesn't exist for plasma panels or traditional CRTs.
LCDs use a liquid crystal solution sandwiched between glass to display
images. Each crystal controls a pixel in the panel and acts like
a shutter, twisting on or off to allow light to pass through or
to block the light. To produce color shadings, a pixel is only partially
turned on to a
so called gray state. Streaking or blurring in the image occurs
as the crystals twist.
Plasma displays, on the other hand, use layers of gas between glass.
Similar to CRTs, images are produced when the phosphor in pixels
across the screen are lit to different intensities to display different
colors.
LCD response times have
historically measured the time it takes for the crystals to go from
full black to full white. But knowing that movies or video games
mostly involve switches between gray states, Connery said many manufacturers
have started to tout gray to gray response times, which can sometimes
be faster than black to white response times.
But consumers aren't necessarily being misled, Connery said, since
gray to gray states are more representative of what people are watching
anyway. The two scales of measurement-and the lack of any hard and
fast standard for consistency in marketing materials -adds to the
confusion.
Samsung's Atash could not quickly affirm without double checking
that Samsung's stated response times for its LCD TVs now refer to
gray to gray instead of black to white.
The slim differences, say between 6 milliseconds and 2 milliseconds,
may not affect the average computer user, but it might for avid
gamers, who usually embrace cutting edge products and might be more
inclined to notice a little blurring while gripped in an action
sequence.
To help provide clarity, some companies try to present both scales
in their detailed product specifications. For instance, ViewSonic
says that its VX924 monitor has response times of 3 milliseconds
for gray to gray and 6 milliseconds for black to white, while its
VX922 monitor is 2 milliseconds for both gray to gray and black
to white.
Such a level of detail wouldn't be practical on store placards,
but Connery says most retail or product information on response
times will refer to the gray to gray scale.
Nevertheless, other key features in the marketplace such as contrast
ratio, resolution, brightness and cable inputs are generally more
important to the quality and price of an LCD display than millisecond
response times.
So what do the expert recommend?
"Consumers should judge with their own eyes," Connery
said, to see if there are any noticeable differences or bothersome
blurring.
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