LCD TV Full Form Name
Full Form of LCD :
Liquid Crystal Display
LCD Full Form is Liquid
Crystal Display. It is one of the most opted technologies for
display of monitors and display devices. LCDs have a wide range of use which
includes televisions, computer monitors, cockpit displays in aircrafts,
instrument panels, and more. LCDs have created a revolution by replacing the
bulky display units with sleek, large, and flat screens. They give an elegant
look to the modern devices.
With the advent of LCD, even
various other common household items such as oven timers and digital clocks
have a new form. The power consumption of liquid crystal display is less with a
high definition output. This is because LCDs do not emit light. Rather they
block light, which makes it comfortable for the eyes too.
LCD Full Form – Additional Information
When television was first
invented it functioned on the cathode-ray tubes (CRT). These made the
television a very bulky piece of electronic equipment that occupied a corner in
the living room. Size- wise and weight- wise the television was a very heavy and
big piece to handle. Nonetheless, since there was no other option available
other than CRT televisions, the market was full of such items. Gradually, the
technology improved and simpler systems of picture development were introduced.
After CRT, LCD or Liquid Crystal Display televisions came into the market.
WHAT ARE LCD TELEVISIONS?
LCD or Liquid Crystal Display
televisions are a step ahead of the cathode-ray tube versions. The technology
for picture display is totally different from the CRT ones and thus, the models
are more compact and sleek in size and shape. Since the LCD televisions are
flat screen televisions, they can be easily mounted on the wall as well as
placed on a table stand. LCD televisions use pixels to create a picture. There
are millions of pixels on an LCD screen. Pixels are the picture elements that
are red, blue and green light.
The picture is produced by rapid
on and off the movement of the pixels. The pixels are turned on and off by
electronically controlled liquid crystals that rotate the polarized light.
The light is at the back of the screen and the pixels are in front. When
the current is passed, it either passes through an active matrix grid or a
passive matrix grid. Passive matrix grid has a grid of conductors with pixels
at every intersection.
The passed current when travels
through any two conductors, the light is controlled on the pixels and picture
is formed. In an active matrix grid, there is a transistor at pixel
intersection and this requires lesser energy to light up the pixels.The current
in active matrix can be controlled well by switching on and off frequently thus
giving a shorter refreshing rate that illuminates the pixels and gives a better
picture quality. Because of the use of a transistor to control pixels, an
active matrix LCD is recognized as TFT or Thin Film Transistor display.
HOW DOES LCD WORK?
As we know, a matter exists in
three forms – solids, liquids, and gasses. However, it is very rare to find
them in a combination of any two states. But in 1888 an Austrian chemist,
Friedrich Reinitzer was successful in finding a liquid crystal that is the
property of matter to exist in an in-between state of liquid and solid
(crystals). Solids are a neat mass with a uniform pattern of atoms in a
crystalline form. Liquids, on the other hand, have no definite shape or size as
they only take the form of the container that holds them. A liquid crystal has
the properties of solid as well as liquid. The two phases of liquid crystal are
known as a smectic and nematic phase.
The nematic phase is the liquid
phase in which the molecules have a free movement and the intermingling of
particles is easy in a linear direction. The smectic phase is the solid part
where the molecules form layers that can move against each other in an easy
manner yet cannot cross over to other layers.
LCD uses the technique of forming
picture through pixel movements. The back of the television screen has a strong
light and there are millions of pixels covering it in front. Each pixel is
composed of smaller sub-pixels that have red, blue or green light. Above all,
each pixel has a polarizing glass behind it and another placed at 90 degrees in
front.
Between the two polarizing
filters lies the liquid crystal in nematic phase in a twisted form. When the
current is passed, it blocks the light by one polarizer and when it is switched
off, the light is allowed to pass through at 90 degrees making the pixel look
bright.
FORMATION OF PICTURE
The picture is formed by turning
on and off of the pixels. There are two polarizing filters – horizontal and
another vertical at 90 degrees. When the pixels are switched off, the light
passing from behind the screen is obstructed and only the light waves that are
traveling horizontally can pass through. A transistor that controls the pixels
turns it off when the electric current is passed. Thus, the liquid crystal in
nematic phase straightens up from its twisted state and allows the light to
pass through uninterrupted.
The light waves emerging from the
crystal are horizontal and they get obstructed by the vertical filter that can
only permit waves that vibrate vertically to pass through. Thus, the opposite
clashes of polarized filters prevent the screen from lighting up and the pixels
are dark.
Contrary to this state, when the
pixels are switched on, the electric current passing through them has been
turned off. Due to this, the liquid crystal gets twisted that reflects the
light waves at 90 degrees. So the light that passes in a horizontal waveform is
sent out in a vertical state. The vertical polarizing filter now allows only
waves traveling in the vertical direction and thus the pixel is illuminated.
The red, blue or green color in the sub-pixels gives the pixel its color and
helps form an image that can be viewed on screen.
ADVANTAGES AND DISADVANTAGES OF LCD
The traditional television was
made of cathode ray tubes that made it a bulky model. LCD televisions have a
flat screen display and thus are compact and sleek. Besides being table mounted
they can be safely put up on the wall, making the room clutter free and giving
a better view without any obstruction. The picture quality is also sharp due to
close-knit pixels and the colors are more real like and vibrant than CRT
picture. LCD technology blocks the majority of the light before it reaches the
viewing screen. Hence, more power is used up to illuminate the pixels thus
making it as inefficient in power saving as the CRT version.
Initially, the LCD televisions
had a poor picture quality and image distortion in fast-moving pictures. The
colors also used to be hazy and muddy and it had a very poor contrast ratio.
However, constant research and development on the product have resolved many
issues and the LCD available now is far more superior quality than the earlier
models. Many big companies like Sony, Sharp, LG etc have been manufacturing LCD
televisions that are as large as 65 inches screen size. The display panel sizes
have crossed 108 inches by Sharp and LG.
KNOWING MORE ABOUT LCD PURCHASE
On an average, an LCD television
has 60,000 hours viewing time after which the picture and color quality is
likely to deteriorate. Nothing lasts for infinity so a daily viewing of 8 hours
is permissible to stretch the lifespan of the display to around 20 years. The
most important factor of the television is the backlight that illuminates the
pixels and the screen. A good quality light source can last for a longer period
than cheap brands. Do not hesitate to invest in good brands like Sony, Sharp
etc as they have high-quality lighting source installed that is guaranteed to
give a longer service than the cheap Chinese or Korean brands that will render
the television dysfunctional due to power breakdown.
The backlight quality is the
deciding factor for the color display and synchronization. Thus, a good product
is a wise buy. LCD work on blocking rather than emitting light. Therefore,
there are very fewer chances of the burn in the process.Even though the
development has allowed the picture quality to be good in larger sizes, it is a
fact that the smaller the screen denser the pixels and higher the sharpness and
color display. LCD televisions have its own pros and cons. Nonetheless, for a
better picture quality, it is definitely a good option than CRT.