2D Simulation of a Coplanar Plasma Display Cell

Results obtained with SIPDP-AC

Principles of coplanar Plasma Display Panels

In plasma display panels the light of each picture element is emitted from a plasma created by an electric discharge. The dimensions of the discharge are in the 100 micro-meters range at a pressure of a few hundred torrs, and the voltage applied between electrodes is in the 100-200 V range.

In the coplanar electrode geometry, the discharge occurs between two parallel coplanar electrodes (sustain electrodes) and a third electrode (address electrode), perpendicular to the coplanar electrodes on the opposite plate, is used to trigger the discharge.

The gap between the plates is filled with a rare gas mixture. Each pixel at the intersection of an address electrode and a pair of coplanar electrodes can be illuminated independently when a voltage pulse is applied between the electrodes. The voltage pulse leads to the breakdown of the gas and to the formation of a weakly ionized plasma which emits visible or UV light.

Scheme of a coplanar PDP cell.

Side view

The coplanar PDP are AC Plasma Display Panels where the electrodes are covered with a dielectric layer. The dielectric layers above the coplanar electrodes are coated with a magnesium oxide (MgO) layer. The role of the MgO film is to protect the dielectric layers and to decrease the discharge voltage due to the large secondary electron emission coefficient of MgO under bombardment by neon ions. The address electrodes and the dielectric barrier ribs around it are covered with phosphors. Due to the charging of the dielectric, the discharge is transient and the pulse duration is on the order of 100 ns in typical conditions (xenon-neon 5-90 gas mixture at 500 torr).

Space and Time Variations of the Electric Potential (lines) and Xenon Excitation (colors) in the Cell
Memory charges are present before the discharge pulse, and the discharge operates in an ON state.
The figures show the plasma formation and expansion above the cathode and anode. The maximum of light
emission is located at the plasma-sheath interface and moves toward the cathode as the sheath contracts.
The plasma spreads on  the anode side due to the charging of the dielectric surface. This is accompanied by
an increase of the UV emission above the anode.
The units of the color scale for the power dissipated into xenon excitation are: 1.8, 5.5, 7.9, 3.8 104 W.cm-3 for
t=133, 150, 157, and 166 ns respectively.

These results have been generated using the software SIPDP-AC from the SIGLO Series developed by Kinema Software

References :

C. Punset, S. Cany, and J.-P. Boeuf, "Addressing ans sustaining in ac coplanar Plasma Display Panels",  J. Appl. Phys. 86, 124 (1999)

C. Punset, J.P. Boeuf, and L.C. Pitchford, "Two-Dimensional Simulation of an AC Matrix Plasma Display Cell. Cross-Talk and other Geometric Effects",  J. Appl. Phys. 83, 1884 (1998)

J.P. Boeuf, C. Punset, A. Hirech, and H. Doyeux, "Physics and modeling of plasma display panels", J. Physique IV France7, C4-3 (1997)