November 6, 2003
A: FROM MENTOR BARB KONTOGIANNIS IN CO
How do Plasma Monitors work?
Plasma technology is different from that used in other display systems in that red, green and blue lights are created in every pixel, reducing the need for space. Charged electrodes between glass panels cause tiny pockets of inert gas to change a state of plasma. This process causes UV light to be produced, which in turn reacts with the red, green, and blue phosphors in each pixel to produce visible light. Unlike traditional displays, where the image is scanned across the screen, in plasma displays all pixels are "lit" at once. Having no electron beam, back lighting or light polarization, the image is inherently sharper and brighter. Perfect from edge to edge.

What is the plasma in plasma tvs?
An electrically neutral, highly ionized substance composed of ions, electrons, and neutral particles. Plasma contains almost equal numbers of free electrons and positive ions. In a plasma the electrons have been stripped away from the central nucleus. Therefore, a plasma consists of a sea of ions and electrons and is a very good conductor of electricity and is affected by magnetic fields. Electrons are separated from their respective nucleus when enough heat is applied .

What are phosphors?
Phosphors are the material on back glass that emit the visible light that makes up the picture we see. On a cathode-ray tube the phosphors are on the front glass and are excited by a beam of light from the cathode-ray. In all flat and plasma tvs the phosphors are excited by UV light produced by electromagnetically charged plasma.

The information above is from www.plasmatvbuyingguide.com. There are diagrams there too if you want to learn more. This site is not the place to go to find out about burn-in, since they're selling TV's and wouldn't want to advertise that negative feature. Plasma TV's ARE susceptible to burn in. What happens is that the phosphors that are not being used age slower than the ones that are, and when you then go and watch a full screen image, the ones that were 'dormant' are now brighter, so you'll see a "ghost" of the previous image (say, the black bars on the side). The length of time before burn in starts is probably a lot longer than 15 minutes (at least 3-4 hours, if not longer). The way they typically work around it (if you're not watching full screen information, i.e., 16:9 format) is to show the bars in gray instead of solid black. That apparently energizes the gas enough to prevent burn in. If the screen is full (no black bars on top/bottom or sides), then burn-in is not an issue, as long as the image is changing. Another way is to stretch the image so that it fills the screen. Some people say the "justify" modes are not bad, others don't like them. Channels with constant banners such as CNN, can be a problem for burn-in as well.

What is being done to improve plasma TV's? I don't know. While plasma is a nice technology, it may not be the technology of the future. Burn-in, life, noise, and altitude issues are all working against it. It probably does provide the brightest picture, especially for off-axis viewing, but is that really worth it, considering you can get other technologies, like Digital Light Projection, for less than 1/4 of the price of an equivalent size plasma? I don't think prices will come down that fast to make it really compete with all of the other technologies that are coming out.