Whereas conventional CRT screens have three separate dots or pixels for red, green, and blue, Plasma screens use pixels that each display all three colours.

The system relies on a series of small pockets of inert gas. Charged electrodes between panels of glass will cause these pockets to change to a state of plasma - hence the name. The result is Ultra-Violet light which reacts with the phosphors in each pixel to produce the coloured light.

CRT screens rely on a process of 'scanning'. In a plasma screen however, all pixels in the screen are lit simultaneously.

The average life-span of a plasma screen will be between 20,000 and 30,000 hours. After this point, the screen will not cease to function, however it's brightness will be around half of that which it was originally. An easier way to understand this life-span is to say that 20,000 hours would be rougly equivalent to having the screen on for 24 hours a day for 2.3 years.

Bibliography:

How plasma works, [Online], Available: http://www.monitors.co.uk/how_works.php [2002-08-16].