Feb 6 2008
Plasma display technology has emerged as an alternative to cathode ray tube or CRT-based televisions. Plasma display technology offers a number of advantages such as the possibility of producing a very large screen and a narrow body.
What is Plasma?
Plasma can be thought of as a gas consisting of positive ions and negatively charged electrons. Under normal conditions, plasma is considered as electrically neutral and the number of positive ions is equal to the number of electrons.
By introducing an electrical current through the plasma, the negatively charged electrons rush towards the positively charged areas of the plasma, and vice versa, the positive ions rush towards the negatively charged plasma areas.
Under these conditions, the charged particles frequently collide with each other and as a result excite the gas atoms in the plasma. This causes the charged particles to release energy photons.
Plasma Screens - How They Work?
Basically, a plasma screen contains hundreds and thousands of tiny cells sandwiched between two glass plates. On both sides of the cells, long electrodes are also sandwiched between the glass plates. The two electrodes are commonly referred to as the address electrode and the display electrode.
The address electrodes are situated along the rear glass plate behind the tiny cells. The display electrodes, which are transparent are situated along the front glass plate and sit above the tiny cells. An insulating dielectric material surrounds the transparent display electrode and it is also covered by a protective layer of magnesium oxide.
The address electrode and the display electrode stretch across the full length of the plasma screen. The display electrodes are organized in a horizontal fashion while the address electrodes are arranged in a vertical manner.
The tiny cells are sealed with two rare gases, xenon and neon. When atoms of xenon and neon are excited, light photons are released. The xenon and neon atoms release ultraviolet or UV photons.
The phosphor material coated on the inside wall of the cell interacts with the released UV photons. The phosphor material emits colored light when it is excited. Each pixel of the plasma screen is composed of three separate subpixel cells: green light phosphor, blue light phosphor and red light phosphor. The overall color of the pixel is generated by blending together these colors.
The intensity of each subpixel color can be controlled by varying the pulses of current flowing through the cells. Hundreds of combinations of red, blue and green can then be created.
How do plasma screens work?
Source: AZoOptics