Your Electronics Open Source

All people, I suppose, know and talk about Plasma television sets, but most of them have not any idea about their structure and their functioning principles.

STRUCTURE

In the below picture there is a PDP ( plasma display panel ) scheme :

A PDP is constituted of two parts : the front substratum ( from spectator side ) and the rear substratum.
The two parts, once connected ,will make a PDP : between them there is a gap of 150-200 µ.
The front substratum is constituted from :
1. Glass panel ( PD200 material )
2. Transparent electrodes (horizontally disposed )
3. Conductive electrodes ( generally silver paste made )
4. Dielectric layer
5. MgO protective layer ( magnesium oxide )

The rear substratum is constituted from :
1. Phosphorous
2. Barrier ribs
3. Dielectric layer
4. Addressing electrodes ( vertically disposed )
5. Glass panel

OPERATING PRINCIPLES

In a PDP the visible light is produced from the phosphorous that have been excited from the ultraviolet ( UV ) radiation.
The UV radiation is generated from a gas that is between the two substratum ( front and rear ).
The gas is excited from a local electrical field.
The electrical field is produced from a voltage that is applied between the conductive electrodes and the addressing electrodes : they are each other disposed perpendicularly and they constitute the addressing grid.
The gas is a mixture of Neon and Xenon : once it is excited, part of it changes in plasma ( mixture of electrons and ions ), part of it moves to a higher status of energy.
The plasma allows the current flow between conductive electrodes and addressing electrodes ( gas discharge ).
The gas part that has moved to a higher status of energy , coming back to the initial status, emits UV radiation.
The phosphorous, hit from the UV radiation, emits visible light.
There are three phosphorous – Red, Green, Blue – and every pixel is constituted from three
sub-pixel, one per colour.
The image is got addressing every sub-pixel that is associated to a junction of the addressing grid.
The luminous intensity of the emission is controlled changing the number of discharges in the time unit.