Slide 1: LIQUID CRYSTAL DISPLAY TELEVISION BY:
SNEHA SHETTY OUTLINE : OUTLINE WHAT IS AN LCD?
HISTORY OF LCD TV
WORKING OF LCD TV
FEATURES OF LCD TV
ADVANTAGES AND ITS DISADVANTAGES
CONCLUSION Slide 3: WHAT IS AN LCD?
An LCD, or liquid crystal display, is a technology used in modern appliances such as watches, computers and televisions. The screen is made of liquid crystals sandwiched between two plates of glass. These manipulate the light and colors on the screen when they change orientation. Slide 4: History In 1988 Sharp demonstrated the first active matrix full color full motion LCD panel.
In 1991 Sharp’s Magohiro Aramoto introduced the first wall hanging television product,
the Liquid Crystal Museum. Slide 5: Sharp has been an industry leader since they first displayed their
full color 14” in 1988. Since then other manufacturers, like Samsung, Hannstar,
LG, Acer, BenQ, HP, Casio, Sony and Viewsonic (among many, many more) have
entered the fray. Slide 6: Working of LCD TV HOW IT WORKS? : HOW IT WORKS? LCD TV technology is based on the concept of liquid crystal display, now used as the world's most popular flat-screen technology. LCD TVs use the most advanced type of LCD, known as an “active-matrix” LCD. This design is based on thin film transistors (TFT) – basically, tiny switching transistors and capacitors that are arranged in a matrix on a glass substrate. Their job is to rapidly switch the LCD’s pixels on and off.
In a color TV’s LCD, each color pixel is created by three
sub-pixels with red, green and blue color filters Slide 8: Depending on the pixel that will get light,the LCD will
Produce the final image. Slide 9: Color in LCD Display Panels For an LCD display to show color, each individual pixel is divided into three sub-pixels
with red, green and blue (RGB) color filters to create a color pixel. This is
somewhat similar to the way CRT and Plasma use different phosphors to glow
red, green, or blue to create color. . Slide 10: With a combination of red, blue and green sub-pixels of various intensities, a pixel can be made to appear any number of different colors.
The number of colors that can be made by mixing red, green and blue sub pixels depends on the number of distinct gray scales (intensities) that can be achieved by the display.
If each red, green and blue sub-pixel can display 256 different intensities of their respective color, then each pixel can produce a possible palette of 16.8 million (256x256x256) colors. Slide 11: Key Features of LCD Television 1) Screen resolution: The native or screen resolution determines how much sharp the
picture will look on the screen.
The screen resolution of LCD TV starts from 720p and
higher (1080i and 1080p). This means its higher native resolution
ensures that picture looks sharper, more detailed and clearer. Slide 12: 2)LCD screen: The size of the screen is the length of the display diagonal from the top corner to bottom. The larger the diagonal, the more you get a cinema effect.
Typically, LCD TV screen size varies between 26" and 40“.
Currently, the largest LCD TV available in commercial market has about
52" screen size. Slide 13: 3)Wide Aspect Ratio: LCD TV with 16:9 Aspect Ratio LCD TV looks typically rectangular as its screen supports 16:9 aspect ratio, which is the standard
screen format of high definition videos.It also supports 4:3 aspect ratio. The feature is worth appreciating, as it ensures that the stretch is least in the center where your eyes are focused and more at the corners, providing you with quality visual experience. Slide 14: 4)Digital sound surround: As high-definition TV signals and videos are encoded in
Dolby Digital 5.1 surround sound, LCD TV comes with audio
connections to connect to home theater speakers so you can
recreate theatrical sound effects in your living room thus
making them versatile. Slide 15: 5)Contrast Ratio: Contrast ratio means the difference between the brightest and darkest values a screen can display. Therefore, the format used by most manufacturers is "XXXXX:1", the 1 being the single darkest point on the screen, and the bigger number representing "units" of brightness. If LCD TV has a low contrast ratio, dark images will look grey and while light images looks washed or blurred. An average contrast ratio to have in an LCD TV is 10,000:1 for 32-inch. Slide 16: 6)Motion Response Time In case you are a sports lover or action movie buff, Motion Response Time is a must check.
Motion Response Time is the ability of an LCD TV to display fast moving objects. On an average, an LCD TV has a Response Time of 6 ms, 8ms or 12ms. Slide 17: 7) Brightness: Without sufficient brightness your image will look muddy and soft, even in a dark room. Viewing distance, screen size, and ambient room light will affect the need for more brightness capability.
A brightness rating listed as 550 cd/m2 or higher is good 8)Scaling:
Scaling is a process where a television's video processor will match the resolution of the incoming signal to its native pixel resolution.
Poor scaling can result in artifacts, such as jagged edges and inconsistent detail. It must also be noted that results also depend on the quality of the incoming signal. Slide 18: 9)Viewing Angle: LCD TVs typically have a good side-to-side viewing angle, with many going as wide as 160 Degrees, or about 80 degrees from the center viewing spot. Slide 19: 10)Connectors: Most LCD panels have both VGA (analog connector to connect to your pc)and a
DVI (digital connector for high definition videos) on them.
The DVI usually has a cleaner and brighter picture compared to
standard VGA connectors. Slide 20: 12)Stands: An LCD TV stand should perform dual functions: it should support your LCD television and look great as part of your living area or bedroom.
An ordinary looking stand will diminish the attractiveness of your new device which might be the reason why you bought your TV in the first place. It will definitely devaluate your viewing experience. Slide 21: Advantages: Occupies less space Elegant design of LCD TV adds beauty
to the interior of your room LCD TV causes less eyestrain There is no screen glare Slide 22: Disadvantage Poor black levels
Slower response times; results in
image “ghosting leaving trails behind
moving images” and blurring of fast images
More expensive to make than plasma
LCD has “screen door” effect
Lower contrast ratio
Limited viewing angle
It has environmental effects. Slide 23: CONCLUSION Despite arguments for plasma televisions, we
believe the future of televisions lies in LCD
Continuous advancements in quality and
overall viewing experience
Increasing Size availability REFERENCES : REFERENCES www.wikipedia.com