LCD Dead Pixels:
LCD, Liquid Crystal Display or Liquid Crystal on Silicon,
has been around for some time. This technology can be
commonly found in popular HDTVs, computer or laptop monitors
and Sony's new PSP. But the downside to LCD screens is
the dreaded "dead pixel" or "hot pixel"
phenomenon. Dead pixels or "hot pixels" are
defined as "a pixel on an LCD monitor that remains
unlit, or black, when it should be activated and displaying
LCD vs DLP TVs
by Bradley James
What are the differences between DLP and LCD
TVs, and which is the better choice for you?
Two new technologies in the world of TV, DLP and
LCD, are now in a tight competition. Not long ago,
everyone was talking about Plasma vs. LCD - which
one would win? It became clear to most that Plasma,
with its short lifespan of just 3-4 years, was simply
not the best choice. In fact, the LCD screen has
several benefits over plasma. For instance, LCD
screens run much cooler than the average plasma
TV, and thus require less power to operate. Plasma
TVs run so hot, in fact, that they require a fan
to cool them down which can be noisy. In
addition, plasma screens have a tendency to degrade
over time, slowly becoming dimmer. LCD screens,
on the other hand, run relatively cool, and do not
degrade over time. Some Plasma owners, who have
used their TVs for a few years now, have already
witnessed the dimming of their screens. Also, LCD
screens tend to have overall better picture quality,
and are typically 10 to 15 percent lighter than
Now the choice is mainly between LCD vs. DLP - two
distinct technologies that offer slight differences
in display, price, and performance. If you are looking
to buy a new flatscreen TV this year, you are probably
wondering which one is right for you.
What are DLP, LCD TV Screens?
DLP stands for Digital Light Processing, while LCD
stands for Liquid Crystal Display. DLP technology,
developed by Texas Instruments, uses a DMD, or Digital
Micromirror Device, contructed of 1.3 million microscopic
mirrors. Each of these mirrors is essentially a
single pixel. When a digital signal enters the DLP
system, each mirror is either activated or not,
resulting in tapestry of mirrors tilting either
towards the DLP light source or away. This process
produces different levels of light and dark reflected
by each individual mirror. The colors are produced
when the DLP light sources run through a red, green,
and blue color filter on a moving wheel. Depending
on the lightness/ darkness of each mirror, the colors
come in an enormous amount of shades, producing
vivid color images.
LCD screens are made of several polarized glass
panels, between which are liquid crystal molecules.
An electric current is run through the crystal molecules,
changing their position in respect to the glass.
As light passes through the molecules, these changes
in angle result in different lightness/ darkness
patterns that produce images on the screen. There
are usually three polarized glass panels, one with
red pixels, blue, and green. This system also produced
very accurate, vivid images, but angle is important.
You may notice that the best colors in an LCD display
are seen straight-on.
Is DLP, LCD TV Screens better than the other?
Simply put, that is a difficult question to answer.
Unlike Plasma TV screens DLP and LCD last much are
longer, and are considered to both have superior
image quality. LCD screens tend to have slightly
better contrast, with a larger range of black and
white color shades. DLP, however, still has faster
refresh rates than LCD (although LCD has been vastly
improved in this area over the last two years).
This can have implications if you are really into
high-action motion (sports, action movies), because
movement may seem a little blurred with LCD at times.
Also, you'll want to remember that in order for
you to get the best color out of your LCD, you have
to sit right in front of it. LCD TVs also have a
slightly shorter lifespan than DLPs, with only 45,000
to 60,000 hours compared to 75,000 hours or more.
As far as price goes, LCD and DLP are still more
expensive than Plasma, but like all things in time,
their price has been coming down. And right now,
DLP is slightly more expensive than LCD, but not
by much. DLP, in our eyes, is the best investment,
at least for the next few years.
Popular DLP TV Units and Prices
Samsung HLP4663W 46" Widescreen DLP TV Monitor:
Toshiba 62HM84 62" HDTV-Ready Projection DLP
Zenith D60WLCD 60" LCD Projection HDTV-Ready
Gateway 56" Widescreen HD-Ready DLP Rear-Projection
About the Author
Bradley James is a senior editor at SciNet.cc, a
website containing many helpful consumer electronics
review articles. For more information on LCD and
DLP TV technology, please visit our LCD vs DLP TVs