How does plasma TV work ?
The core of the plasma TV or PDP’s operation boils down to two things, the plasma and the concept of cells. First let's take a look at what a cell is like. As with any other display technology, the overall image is composed of a number of pixels. Each pixel is individually produced or displayed on the screen for each and every image. In plasma TV each pixel is produced by corresponding cells (in a monochrome display there will be one cell per pixel and in color there will 3 per pixel). Thus, depending on the screen’s resolution there will be many thousands of such cells which help in producing the image. For example in a standard 1080p display this means there will be 1920x1080 = 2073600 (over 2 million) pixels, which imply up to over 6 million cells.
In a plasma TV these cells are held between two plates of glass. Each individual cell contains gas - xenon, neon and helium. The figure below shows a color PDP with the 3 cells (one each for red, green and blue) forming a pixel. Behind the rear plate of glass and in front of the forward plate are electrodes, which are held in an insulating dielectric medium. The combination of electrodes – horizontal and vertical – causes the cells to be individually excited. In particular, a voltage difference is setup between the forward electrode and the rear one, causing the gas that is in the cell to ionize into a plasma.
Whenever a proportion of the particles of a gas are ionized it is said to be in plasma form. The gas conducts electricity in the plasma form. In a plasma TV the electrical conduction properties are used to excite the phosphor lining at the back of the plasma TV cell. Once the phosphor is excited it emits light of a certain color. The intensity or brightness of the light produced is controlled by a technique called pulse-width-modulation, whereby the pulse-width (amount of time that the current is applied) controls the individual cell’s perceived intensity. Also, by controlling the combination of the three cells, the desired color can be produced.