|
|
Direct View LCD TV's Buying Guide
|
|
| In
an LCD TV, images are formed by thousands of pixels turning on,
off, and everything in between. Light from a fluorescent lamp passes
through these pixels and tiny color filters before traveling on
to your eyes.
Basically, LCD panels are made of two layers of a glass-like material,
which are polarized, and are "glued" together. One of
the layers is coated with a special polymer that holds the individual
liquid crystals. Electric current is then passed through individual
crystals, which allow the crystals to pass or block light to create
images. LCD crystals do not produce their own light, so an external
light source, such as florescent bulb is needed for the image created
by the LCD Television to become visible to the viewer.
Unlike standard CRT and Plasma televisions, there are no phosphors
that light up, and, thus LCD panels are thin and require less power
to operate. Because of the nature of LCD technology, there is no
radiation emitted from the screen itself, unlike traditional televisions.
Also, LCD televisions can be made very thin, thus allowing them
to be hung on a wall or placed on small stand on top of a table,
desk, dresser, or cabinet very easily.
|
 |
 |
| LCDs
are all around us. Liquid crystal displays are so common,
in fact that most people can’t get through their day
without using one. This technology is utilized in digital
clocks, microwave ovens, car dashboards, calculators, stereos,
thermometers, and even some bathroom scales. The applications
for liquid crystal displays are almost limitless and have
revolutionized the most basic home appliance, the television
set. But how does it work?
LCD monitors work by blocking light. By sandwiching a solution
of TN liquid crystals between two perpendicularly aligned
panes of polarized glass, it becomes possible to manipulate
the intensity of light as it passes through this crystalline
matrix and out the glass panel at the other end. Depending
on the voltage of the electrical charge running through them,
liquid crystals will untwist so that the intensity of light
able to pass through the second polarized pane is affected.
Basically, these displays can switch between light states
(where the liquid crystals are fully twisted) and dark states
(where the liquid crystals are fully untwisted), or somewhere
along the gray scale in between. A liquid crystal display
consists of an array of tiny segments called pixels that are
manipulated to form images or to present information. Addressing
is the process by which pixels are turned on (which disables
the passage of light) and off (which enables the passage of
light) so as to create an image on the polarized display pane
in front of you.
|
|
 |
| In
1996, the Federal Communications Commission (FCC) enacted
legislation convincing the nation's 1600+ television stations
to change the way they broadcast their programming and to
start transmitting it digitally. Digital
Television (DTV)
began rising in America ever since then. For now, the FCC
allows the media to offer digital broadcasts in parallel with
their existing analog ones, giving consumers the opportunity
to watch regular TV while they make the switch to DTV.
Once the transition to digital TV is complete it is estimated
that by the year 2006 85% of US households will get digital
feeds, meaning that DTV will be the new standard in broadcasting
replacing analog broadcasting. Sure, you'll still be able
to watch your favorite shows in analog like always, but you'll
need to "update" your existing TV with a device
that converts digital signals into analog ones. All of which
begs the question: Why not just go with the digital flow?
|
|
 |
| It's
easier to watch Just like Plasma Televisions flat-panel
displays like LCDs are significantly brighter and feature
higher contrasts than traditional CRT sets. This means that
an LCD Television will perform remarkably well under most
ambient light conditions. A brightly lit room won't wash out
its picture, and lamplight won’t cause a glare on your
LCD television screen. The beauty of these flat screens is
that you don't have to turn out the lights to see the image
clearly and easily. You don’t have to worry about any
strain on your eyes either, since LCDs don’t flicker
the way old-fashioned TVs do.
Viewing Angle You can watch
TV from almost anywhere in a room since flat-screen LCD displays
can have up to a 160° viewing angle, which means your
LCD Television will look good when viewed from any point 80°
in either direction from the center of the display.
Tuner is included Unlike many
Plasma Televisions LCD TVs generally come with tuners and
speakers already built in, so they're more or less plug-and-play
devices. Since most LCD TVs don't require external tuning
devices, they are ideal for smaller applications, where space
is a concern (like bedrooms and small living rooms) or where
clutter is inconvenient.
Picture is smooth, colorful, and wide
LCD Televisions have none of those annoying scan lines that
conventional sets do. This owes to the fact that each sub
pixel has its own transistor electrode, which creates smooth,
evenly lit images across the entire surface of the display.
It also enables these displays to reproduce images that are
saturated with color. (256 shades of red x 256 shades of green
x 256 shades of blue = 16.8 million different colors).
The display is multi-functional and
long-lived An LCD is a television monitor, capable
of displaying HDTV, regular TV, and home video. It's also
a computer monitor. In fact, it can accept any video format.
LCD displays include many inputs including composite video,
S-video and component video, and one or more RGB inputs from
a computer. Because of the high resolution of LCDs, text and
graphics look especially sharp when viewed on them, which
makes them the best solution for displaying data and web-based
content.
You can expect to use your LCD monitor in many capacities
for many years: The average lifespan of one of these displays
is 60,000 hours. If watching TV was your full-time job, and
you did it 24 hours a day, it would take you almost 7 years
to wear out your LCD display. With more normal viewing habits
of, say, 8 hours per day, you can extend the lifespan of your
TV by a decade or more (to about 20 years)! |
|
 |
| LCD
VS Plasma - At first if you were dreaming of a super
size flat screen for your home entertainment center Plasma
Televisions were your only option. But recently large-format
LCD TVs have been competing with plasma displays in prices
and sizes.
Right now, Plasma Televisions have an advantage and that’s
partly because, at the moment, large LCD Televisions simply
can't compete on price. It's also because plasma screens have
a greater response time than most LCD TVs which makes LCD
Televisions less than optimal for moving images such as video
or games. The drawbacks that Plasma TV screens had in the
past such as stationary images burning in and producing permanent
ghosting has diminished greatly in newer products. For example,
some new companies have developed technology to deal with
the problem by moving stationary pixels just enough to prevent
such burn-in.
But LCD Televisions do have some advantages over plasma. If
you're contemplating a home entertainment setup involving
a PC or other activities involving text as well as graphics,
you'll get a crisper, brighter image from an LCD. LCD modules
are in use for all types of products, from handhelds to monitors
to TVs. As time passes larger LCD TVs will be available at
lower prices, because they offer better screen quality, higher
reliability (LCD TVs have none of the burn-in issues associated
with plasma), and longer product life. LCD Televisions last
for about 50,000 hours versus 30,000 hours for today's plasma
screens. LCD TVs weigh 10 to 15 percent less than plasmas
of comparable size. They often look better in daylight than
plasmas, though plasmas have a brightness advantage at night.
LCD VS CRT Monitors - Free from
the bulky shape and size of the CRT screen an LCD Screen is
light and slim in size, compare a 15-inch deep, 30-pound CRT
against a panel that's less than 7 inches deep (including
the base) and weighs 12 or 13 pounds. It's easy to see the
advantages of LCD monitors, they don't have CRT's focus problems,
and their clarity makes it easier to view higher resolutions
at smaller screen sizes. The latest LCD monitors are all digital,
unlike CRTs this means that graphics cards with digital outputs
don't have to convert the graphics information into analog
form as they would with a typical CRT monitor. With LCD TVs
you will get a high quality image with very little eyestrain
due to the flat screen and the screens do not flicker unlike
in the CRTs.
|
|
 |
| Dead
Pixels - A flat panel LCD may contain some "dead"
or faulty pixels. These are usually easy to spot: they show
a constant color. Dead pixels are the result of the manufacturing
process and they cannot be "revived". Dead pixels
can be irritating, especially if you use the flat panel to
watch movies, if you cannot accept dead pixels, make sure
you check the screen first before buying.
Aspect Ratio - LCD displays come
either with a 16:9 aspect ratio (16 units wide to 9 units
high), the proper one for viewing HDTV and for watching DVDs,
or with a 4:3 aspect ratio, the norm for most broadcast television
shows. If you decide to go with a widescreen (16:9) display,
it doesn’t mean that you'll have to watch some shows
that are not shown in widescreen format with images distorted
or stretched unnaturally. When displaying a "normal"
or 4:3 picture image from satellite, VCR, or cable TV, the
image can be viewed in a number of ways-in its original format
(with black or gray bars on the sides of the screen), or in
"full" mode (where the image is converted or "stretched"
using specially designed algorithms to reduce the visible
stretch marks as much as possible). Again, the quality of
the picture produced under such circumstances depends largely
on the quality of the television you purchase.
Viewing Angle - If you’ve
used a notebook computer before, you'll know that the LCD
offers the best view when you look at it at a certain angle.
Some LCD monitors have wide viewing angles, thereby enabling
you to see what's on the screen even if don't view it directly
in front of you. However, some people find narrow view angles
in notebook computers useful, since they prevent other sitting
close to you to see what's on your screen. Above 120 degree
is considered good.
Contrast Ratio - The LCD doesn't
emit light on its own but relies on a backlight to illuminate
the screen. A dark screen doesn't mean the backlight isn't
working; the pixel merely block off the light from transmitted
through the liquid crystal layer. The contrast ratio is measure
of how many brightness levels the LCD can have. Generally,
a contrast ratio of over 250:1 is considered good.
Brightness - How bright can an
LCD be? The truth is the LCD can be brighter than a CRT. But
generally, the maximum brightness of the LCD is around 225
candelas per square meter, compared to the brightness of a
TV screen.
Screen Size - Like conventional
CRTs, the LCD is also measured in terms of its diagonal screen
size. However, take a note that the LCD doesn't have a black
border like the CRT. Thus, a 15.1" LCD shows the full
15.1" screen (which typically is 1024 x 768 pixel resolution).
A 17.1" LCD will show 1280 x 1024 pixel resolution.
|
|
 |  | |
|
|
|