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| How Plasma Works Simple Def. |
Plasma is a flat, lightweight surface covered with millions of tiny
glass bubbles. Each bubble contains a gas-like substance, the plasma,
and has a phosphor coating. Think of the bubbles as the pixels.Now, think of each pixel-bubble as having three sub-pixels - one red, one green, one blue. When it is time to display an image signal (RGB or video), a digitally controlled electric current flows through the flat screen, causing the plasma inside designated bubbles to give off ultraviolet rays. This light in turn causes the phosphor coatings to glow the appropriate color. Millions of RGB bubbles glow and dim to make a rich, vivid image on your plasma TV. |
How plasma displays work Detailed
Despite rival technologies developing every
year, plasma screens are still the most desirable big screen system, so how do
they work their magic?
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Plasma display panels (PDPs) emerged from corporate and public information screen arenas and are now increasingly common in homes as slimline replacements for bulky cathode ray tubes (CRTs) inside traditional TVs. CRTs require a large amount of heavy glass, and there's no way to cut down the depth behind the screen because of the distance needed by the cathode ray electron gun.
PDPs require much less depth, and range in diagonal width from 30 to 80 inches. Various refinements have been made to PDP construction over the years, and frills such as attractive styling, TV tuners and easily connectable inputs make plasmas more living-room friendly. However, the basic technology remains the same.
A PDP image is comprised of hundreds of thousands of pixels, or picture elements. The arrangement of pixels is similar to that of LCD panels but instead of the individual transistors used for each pixel in LCD, the pixels in a PDP use plasma gas in conjunction with an electrical discharge. The usual construction of a PDP is for the plasma to be contained in hundreds of thousands of phosphor-coated cells. An electrical discharge creates ultraviolet rays within the plasma. These are invisible to the human eye but they react with the phosphor to produce visible light, just like a fluorescent lamp.
The cells are sandwiched between two plates of glass, plus electrodes at the front and back of the cells covering the screen's entire width. Using this grid of electrodes, the computer inside a PDP can control the electrodes that intersect at a particular cell. Within each cell are three subpixel cells containing red, green or blue phosphors. The PDP's control system can vary the pulses of electricity to cells to vary the intensity of each subpixel, to produce the various colours of the spectrum needed to create an image. Advantages of plasma displays include wide viewing angles, perfect geometric flatness and, in many cases, highdefinition XGA pixel resolution. However, plasma screens are not without drawbacks – one being screen burn. If a static part of an image is displayed for too long it can become burned into the cells, permanently in chronic cases. Subpixels can also ‘die', showing up as an always bright or dark dot. Finally, the luminance of phosphor emissions decreases, so that after a few years of use, a PDP can look half as bright as when it was new. Contrary to popular belief, the microscopic plasma cells cannot be ‘regassed'.