Liquid crystal diode (LCD) displays contain liquid.
The term "liquid" refers to the motion and pliability of the crystals.
The twisted nematic (TN) liquid crystal is the most common type of
liquid crystal being used in display applications today (e.g., LCD
televisions, LCD monitors, and LCD projectors). It has a naturally
twisted crystalline structure. A particular feature of this crystal is that
it reacts to electric currents in predictable ways (like liquid does).
LCD TV sets last forever.
The average lifespan of an LCD display is 60,000 hours. With more
normal viewing habits of, say, 8 hours per day, you can extend the
lifespan of your TV by a decade or more than 20 years. I wish my
tube TVs lasted that long.
A primary concern is the actual lifespan of the light source in your
LCD. This is the critical component of your display unit. It is
particularly important for maintaining a proper white balance on your
TV. As these florescent bulbs age, colors can become unbalanced,
which could result in too much of a particular color in your picture.
So, it pays to buy name-brand displays.
LCD TVs suffer from burn-in.
Not true. LCD monitors work by blocking light, so it is literally
impossible for burn-in to occur on the screen. Light is not created by
the liquid crystals themselves. Instead, a light source (bulb) behind
the panel shines light through the display, which uses liquid crystals
to manipulate the intensity of that light. When light is generated from
a source external to the display screen itself, images cannot be
permanently retained.
You cannot watch an LCD TV from an angle.
It is sometimes the case that LCD displays have impaired
side-viewing angles. Manufacturers will tell you just the opposite,
that LCD TVs have viewing angles to rival comparably-sized plasma
displays (160° or more). But this is simply not true. While it is
sometimes possible to view LCD televisions 80° off axis, the picture
you'll see will be degraded. In other words, there will be a noticeable
decrease in color saturation, brightness and contrast in the picture.
If you buy an LCD display from one of the better manufacturers, you
should be able to sit about 70° off axis and still see a perfectly
displayed imaged. Dot pitch is an important factor here. Higher dot
pitches increase the viewing angles of LCD panels. Smaller dot
pitches make for sharper images. You generally want a dot pitch of
.28mm ("10,000 pixels/in2 of your display) or finer.
LCDs are no good for watching movies.
Response time of these displays have dramatically increased,
resulting in even smoother on-screen presentations. One way to
think about response time is in terms of the amount of time it takes a
pixel to "refresh" itself. Response time is measured in milliseconds
(ms), with the best LCD monitors now clocking in with response
times under 20ms. Slower response times (>20ms) can cause the
image on the panel to lag and appear jerky, showing trailing effects.
Another phenomenon associated with slower response times is
ghosting. This occurs when the display is made to switch quickly
from light to dark states, or vice-versa. In these instances,
on-screen images may appear to stay on the screen belatedly.
The size and the quality of LCD panels determine how much or how
little on-screen movement results in trailing effects. Better quality
LCD displays have benefited much from improved response times.
Still, no LCD display is entirely immune from trailing effects, though
response times are expected to reach the under- 5ms mark soon.
LCD TV is replacing plasma TV.
Some say that LCD is replacing plasma as the premier flat-panel
display technology. Not so. While LCD may seem like the obvious
technology for digital signage applications, given its relative
durability and imperviousness to burn-in, LCD monitors have not
exactly outpaced their plasma counterparts in the commercial arena.
Nor has LCD technology beaten-out plasma as the best-selling
home-theater displays in America.
So, anyone who says that LCD technology has displaced plasma
technology is mistaken. While LCD displays have become
increasingly visible in the fixed-pixel display market, plasma is still
preferred in the over 40" display category.
