LCD

LCD displays use an array of liquid crystal
elements to create the image; a backlight creates the light, and the
display uses the liquid crystal elements to control how much light
passes through tor each the viewer. LCD technology is cheap to
manufacture and is relatively energy efficient, making it very popular
in HDTVs and other display devices such as computer monitors and cell
phone displays.

The display passes an electrical signal to each liquid crystal on the
LCD display that controls how much light can pass through it, thus
controlling the brightness. Each liquid crystal elements can be
individually controlled, and color is produced by using filters on the
individual liquid crystals. LCD televisions group three elements (for
red, green and blue) together to form a singl pixel. By moderating how
much light is allowed through each of these three liquid crystals, any
one of the pixels can produce any color in the spectrum.

There are various negatives to LCD displays. One of the problems is
that it takes a certain amount of time for each individual liquid
crystal to change the amount of light that is let through. This can
result in ghosting on the display as the crystals lag behind the image,
especially in fast action sequences that change quickly. Another
problem with LCDs is viewing angle. Each liquid crystal can be thought
of as a small pipe that lets light through from the backlight. As the
viewer moves off from right in front of the display, less light reaches
them. Other technologies, like Plasma, create the light closer to the screen, with the result that the light exits the pipe at a wider angle than an LCD allows.

LCD displays also have trouble producing blacks as deeply as other
technologies like Plasma. This is because the backlight on the LCD is
always on, so some light always escapes even when the individual pixels
are showing black. Some manufacturers are attempting to address this
issue by using multiple backlights and dimming them selectively, but
because the number of backlights is nowhere close to the total number
of pixels this local dimming is imprecise.

LCD dispays do have several benefits, for example they are not
susceptible to the phenomenon known as burn-in where a “ghost” of an
image can remain on the display even after it has been changed. This
makes LCDs a good choice if you are going to be displaying a static
image for an extended period of time. LCD displays are also capable of
producing a very bright image, especiallly compared to Plasma
televisions. Finally LCD televisions are relatively inexpensive to
produce, something that has vaulted them to a dominant position in the
HDTV market.