Plasma (PDP) HDTV
Plasma Display Panels (PDPs) was one of the first flat screen television technologies and was sucessfully used to make some of the earliest high definition TV screens. They work using gas cells sandwiched between two thin glass sheets. Electrodes ionise the gas to form a plasma and emit ultraviolet light. The ultraviolet light excites phosphors which in turn emit visible light.
Advantages Of Plasma
Plasma panels have been production manufactured at large sizes for a number of years, allowing the technology to be refined, resulting in several advantages over other HDTV display technologies:
- The phosphors used emit the same colour light as those in conventional cathode ray TV sets. Since colour standards were driven by the established CRT technology, the colour fidelity of colour plasma displays is very good.
- Plasma displays can have very high contrast ratios (difference between the darkest and brightest parts of the screen).
- The background light emitted by a plasma display is relatively low, resulting in blacker blacks.
- Plasmas have a wide viewing angle.
There are a few disadvantages also:
- High power consumption. Plasma sets draw several hundred watts of power to generate their picture. You can reduce power consumption by reducing the brightness of the display.
- The phosphors is a plasma display degrade (become less bright) with use. If static images are displayed on plasma TVs, some areas of the screen degrade faster than others, resulting in "burn in". This burnt in image is visible all of the time. Manufacturers are continually developing techniques to overcome this problem, but it remains a significant disadvantage of plasma displays.