Liquid crystal display

CG

1. LIQUID CRYSTAL DISPLAY

2. DEFINITION Liquid Crystal Display (LCD) is a thin , flat panel used for displaying information such as text ,images and moving picture . Its is used in Computers , Televisions, calculators etc.

3. UnPolarization Light Light emitted by the sun, by a lamp in the classroom, or by a candle flame is unpolarized light. Because light waves traverse in all the directions.

4. Polarization The process of transforming unpolarized light into polarized light is known as polarization . (i.e.) Polarized light waves are light waves in which the vibrations occur in a single plane.

5. WORKING PRINCIPLE

6. WORKING PRINCIPLE LCD ‘s are made of organic molecules when any electric field is applied the c rystals present in the LCD rearrange themselves because they are in liquid state. Whenever Light enters through the first layer, it gets polarized because of the polarized crystals. Afterwards a dark spot appears on the screen.

7. PROS OF LCD 1) Smaller size 2) Lower power consumption. 3) Lighter weight 4) Longer life 5) No Suffer in Problem.

8. C ONS OF LCD Cost is higher than CRT monitors. N arrow Viewing angle.

9. LED

10. WHAT IS DIODE A diode is an electronic component with two electrodes called the anode and the cathode . The fundamental property of a diode is they conduct electric current in only one direction .

11. WHAT IS Light Emitting Diodes A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it.

12. WORKING PRINCIPLE OF LED When 2 materials one with full of electrons and the other filled with holes brought close contact to each other and when electric field is applied the electrons move from valence band to conduction band resulting in emitting of light.

13. PROS OF LED Higher brightness. Light weight No viewing angle differences. The screen size is up to 90inches which is higher than other displaying devices.

14. PROS OF LED Consumes more power than LCD’s