Flat panel displays and plasma panel displays

Flat panel displays and plasma panel displays

1. FLAT PANEL DISPLAYS

2. It is a class of video devices that have reduced volume, weight and power requirements compared to a CRT . Currently used in TV monitors, Calculators, pocket video games, laptop computers & advertisement boards etc. They are thinner than CRT’s .

3. Two types of Flat Panel Displays : 1) Emissive Displays 2) Non-emissive Displays . Emissive Displays : are devices that convert electrical energy into light. Examples are Plasma panels, thin-film electroluminescent displays and Light-emitting diodes(LED ). Nonemissive Displays : Use optical effects to convert sunlight or light from some other source into graphics patterns. Example is Light-crystal device(LCD).

4. A  plasma display panel  ( PDP ) is a type of flat panel display common to large TV displays 30 inches (76 cm) or larger. They are called "plasma" displays because they use small cells containing electrically charged ionized gases, which are plasmas. Plasma panel functionally very similar to the DVST even though its construction is markedly different. PLASMA PANEL DISPLAYS

5. A plasma display is a computer video display in which each  pixel  on the screen is illuminated by a tiny bit of plasma or charged gas, somewhat like a tiny neon light Plasma displays are thinner than cathode ray tube (  CRT  ) displays and brighter than liquid crystal displays (  LCD  ). Plasma displays are sometimes marketed as "thin-panel" displays and can be used to display either  analog  video signals or  display modes  digital computer input.

6. CONSTRUCTION OF PLASMA PANEL DISPLAY

7. WORKING OF PLASMA The space between two glass plates is filled with neon-based gas and sealed. By applying voltages between the electrodes the gas within the panel is made to behave as it it were divided into tiny cells, each one independent of its neighbours. These independent cells are made to glow by placing a firing voltage of about 120 volts across it by means of electrodes.

8. The glow can be sustained by maintaining a high frequency alternating voltage of about 90 volts across the cell. Due to this Refreshing is not required. WORKING OF PLASMA(Contd.)

9. Advantages : Refreshing is not required Produces a very steady image , totally free of flicker. Less bulky than a CRT. Allows selective writing and selective erasing, at a speed of about 20 Micro sec per cell. PLASMA PANEL DISPLAYS

10. Disadvantages: Relatively poor resolution of about 60 dots per inch. Costlier than CRT’s. PLASMA PANEL DISPLAYS