Plasma TV's World

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How Plasma Works

Televisions were originally built using the basic technology as they always have up until recent years. They were all built using the cathode ray tube (CRT). Televisions using this technology worked by a beam of electrons, which caused negatively charged particles to be fired inside a large glass tube. Electrons would excite phosphorous atoms across the wider end of that tube which would make the phosphorous atoms create light. The image seen on the screen was made by lighting up different parts of the phosphorous coating with different colors at different intensity levels. This created the image seen on the screen.

CRTs make very sharp and crisp images; however, they are extremely bulky as evidenced by the back of a CRT television. In order to make a larger screen you have to increase the size of the tube and this makes for a very large and very heavy system.

Invention of Plasma

With the invention of the plasma screen, all this is a thing of the past as the footprint, or amount of space taken up by the unit, is much smaller along with the weight of the unit. Compared to a traditional CRT television, a plasma screen TV takes up as little as six inches of space. The science behind how these marvels works is quite amazing.

In a normal TV, lighting up thousands of tiny pixels on the screen creates the images in a specific pattern as received from the video signal. These pixels come in three colors red, blue and green. The varied intensity sent to each pixel creates the different colors and light intensities as seen on the screen.

A plasma screen TV works a little differently. The plasma display will illuminate very small fluorescent lights that are made up of three smaller lights a red, a green and a blue light. The plasma screen TV will vary the intensity of the lights to create the image on the screen, much like a CRT television.

What is Plasma?

Plasma is a gas that is made up of free-flowing ions. Normally, this gas is full of uncharged particles, which means that the positive and negative charged atoms and particles balance each other out. This leaves the gas with a neutral charge. Once electrical voltage is introduced to the gas, free electrons are introduced and the gas changes almost immediately. When the electrons come into contact with the atoms, other electrons are knocked loose, and the atom loses an electron causing its balance becoming positively charged. An ion is created.

When the plasma has an electrical current running through it, the positive atoms will rush towards the negatively charges area of the plasma and the negative atoms will rush to the positively charged area of the plasma. All this moving about inside the plasma causes the gas atoms to release photons. The two atoms that release these light photons are called xenon and neon atoms. They release ultraviolet light photons, which are then used to excite the visible light photons.

Plasma in the Screen

The xenon and neon gasses that are used in the plasma screen is held in hundreds of thousands of tiny cells that is in-between the two panes of glass used on a plasma screen TV. Along the glass, in-between the cells are long electrodes as well as what are known as address electrodes that are located on the rear glass plate. Insulated by a dielectric material is the display electrode with a magnesium oxide protective layer covering it all and is located on the front glass plate.

The two sets of electrodes are set across the entire screen. The display electrodes are set in horizontal rows while the address electrodes are set in vertical rows. This will create a simple grid across the whole of the screen.

The computer in the display will charge the electrodes that intersect a cell causing the gas in that cell to become ionized. This will cause that cell to release ultraviolet particles. Those particles will then interact with phosphor material that coats the inside wall of the cell causing the phosphor electrons to jump up to a greater level of energy as the atoms gets hotter. The electron will fall back to its normal level and at that point it will release energy in a visible light photon.

Each phosphor will give off a colored light during these reactions. As each colored light is displayed, the Plasma Screen TV will display an image on the screen that is visible to the eye. This happens thousands of times in a second and continues rendering what is seen based on the information being fed to the computer.

Pros and Cons

The main advantage to this is the ability to make a large screen television that takes up very little space, weighs a lot less that a traditional CRT television and has a much sharper and well-defined image. The major drawback has always been the price; however, as technology advances, the cost of making a plasma screen television has been dropping steadily. Prices will continue to drop as the process of making them becomes more refined and easier eventually rendering the old CRT screens completely obsolete.