How Does Plasma TV Work?

The basic idea of a plasma display is to illuminate tiny colored fluorescent lights to form an image.

Each pixel (the tiny dots on the display) is made up of three fluorescent lights - a red light, a green light and a blue light - which are evenly distributed on the screen. By combining these colors in different proportions and intensities of different lights, the television set can produce the entire color spectrum.

Actually, the first plasma display monitor was invented in July 1964 at the University of Illinois, by professors Donald Bitzer and Gene Slottow, but it could only emit green or orange light, and only in 1992, the world's first full-color display was presented. Now, the largest one, presented in 2006, in Las Vegas, at an electronics exhibition, measures 103 inches (261.6 centimeters).

The central element in a fluorescent light is plasma, a gas made up of free-flowing ions (electrically charged atoms) and electrons. Under normal conditions, a gas is made up mainly of uncharged particles, meaning that the individual gas atoms include equal numbers of protons and electrons, so that the net charge is zero.

By introducing many free electrons into the gas, through an electrical current, they will collide with the atoms, freeing other electrons inside them, and altering the balance, turning the atoms into ions that release photons of ultraviolet light.

Xenon and neon atoms, used in the plasma screens that release light photons when excited, are contained in hundreds of thousands of tiny cells positioned between two glass plates, along with long electrodes, on both sides of the cells. The address electrodes sit behind the cells, along the rear glass plate, and the transparent display electrodes, insulated with a dielectric material and covered by a magnesium oxide protective layer, are mounted above the cell, along the front glass plate. Both sets of electrodes extend across the entire screen, the display electrodes in horizontal rows and the address electrodes in vertical columns.

When the intersecting electrodes are charged, an electric current flows through the gas in the cell, making it release ultraviolet photons that interact with the phosphor material coated on the inside of the cell, and this in turn gives off visible light photons.

Each pixel is made up of three separate subpixel cells, each with different colored phosphors - red, green, blue - that, when excited, give off colored lights that blend together to create the overall color of the pixel. By varying the pulses of current, the computer control system in each TV set can increase and decrease the intensity of each subpixel color to create as many as 9 billion combinations of colors.