Fundamental principle of Plasma Display Panel (PDP)s




A plasma display is an element displaying letter or graphic using light from plasma, generated during gas discharge. Plasma Display is divided into Direct Current type and Alternating Current type. Electrode used to supply voltage from the outside and make plasma is exposed to the plasma directly and conduction current flows directly through electrode, which is Direct Current type. On the other hand, the electrode is covered by a dielectric and it is not directly exposed. So, displacement current flows, which is Alternating Current type.

And also it is divided into Partners Facing Discharge type, Surface Discharge type, Barrier Rib Discharge type, etc in accordance with the electrode structure of discharge cell. In case of using visible rays directly from discharge gas, it is mostly used for single color displaying PDP element. For a typical example, there is a PDP using orange color from Ne gas. If full color display is required, ultraviolet rays from discharge gas such as Kr or Xe excite red, green, and blue phosphors and generate visible light, which is available.

A plasma display panel (PDP) is essentially a matrix of tiny fluorescent tubes which are controlled in a sophisticated fashion. There are two main types, DC and AC of which the latter has become mainstream because of simpler structure and linger lifetime. This section treats the AC type.

A plasma discharge is first induced by the positive period of an AC field and a layer of carriers is shortly thereafter formed on top of the dielectric medium. This causes the discharge to stop but is induced again when the voltage changes polarity. In this way, a sustained discharge is achieved. The AC voltage is tuned just below the discharge threshold so the process can be switched on/off by adding a relatively low voltage at the address electrode.

The discharge creates a plasma of ions and electrons which gain kinetic energy by the electric field. These particles collide at high speed with neon and xenon atoms, which thereby are brought to higher-energy states. After a while, the excited atoms return to their original state and energy is dissipated in the form of ultraviolet radiation. This radiation, in turn, excite the phosphors which glow in red, green and blue (RGB) colors, respectively. Since each discharge cell can be individually addressed, it is possible to switch on and off picture elements (pixels).




Procedure of PDP driving


1. Off state




2. Apply voltage pulse to electrodes




3. Produce plasma discharge




4. Generate vacuum ultraviolet




5. Excite R, G, B phosphors




6. Emit R, G, B visible light