1. LIQUID CRYSTAL DISPLAY (LCD)
Asst.Prof.Sreelekshmi.S

2. LIQUID CRYSTAL Substance between a solid and a liquid
layers of "rod-shaped" molecules.
Within a layer, the molecules have the same orientation but differs across layers by a fixed angle
twisted structure
Applied voltage leads to untwisting resulting in varied orientation angles

3. when polarized light passes,
the molecules change
the polarization direction to
match their own angle .
Thus we can effectively
rotate the polarization
direction of the light wave by
a certain angle.

4. LIQUID CRYSTAL DISPLAY
Presence of light source
liquid crystal sandwiched
between two polarizers that
have perpendicular axis of
transmission.
Polarizers & crystal for
intensity control
Red green blue filters for colour

5. Polarizer passes only light of
polarisation same as that
of its axis of transmission
Light out of the liquid
Crystal,is rotated by
90 degrees
The voltage applied
controls the amount of untwist of crystal molecules,thus limits the intensity of light
Relative intensities of RGB give colour to a pixel

6. Advantages of LCDs Physical Size
Compact and Lightweight
Space saving
Can be mounted on a wall or panel
Power Consumption and Radiation Emission
Consume less energy and more durable
Consumes fewer watts than a CRT.
Can reduce electric bill by 40-85%.

7. Viewing Does not emit Radiation
Not subject to Electromagnetic Interference
Viewing
Cause less eyestrain
Does not flicker or glare

8. Disadvantages of LCDs Resolution Viewing Angle
Displays Native Resolutions (Resolution that it displays best)
Viewing Angle
Smaller, needed to be viewed more directly from the front.
From the side the images on an LCD screen can seem to disappear, or invert colors.

9. Price Installation Response Time
Upfront cost it is more costly but long-term cost but will conserve energy in the long run.
Installation
Need a plug interface to connect to the computer
Response Time
slower. The delay can cause a ghosting effect on images it displays.
Requires backlight
Effected by Temperature and sunlight

10. APPLICATIONS laptop computers digital clocks and watches
microwave ovens
CD players 
And other electronic devices..