Plasma Display Panel (PDP) Resolution Enhancement Technology

Upgrading PDPs for use as SHV displays

PDPs use the same light-emission principle as fluorescent lights. A discharge in a gas generates plasma and the excited particles^*1 radiate ultraviolet rays that cause the phosphors coated inside the cell to emit light. An SHV display with 4,000 scanning lines for home use would be a 100-inch (diagonal) PDP in which each small fluorescent light (micro cell), which becomes a pixel for image presentation, is approximately 1/3 the size of those in conventional PDPs. Its pixel pitch would be approximately 0.3 mm (Figure 1). However, the smaller cells increase the percentage of excited particles lost at the cell walls, resulting in lower luminous efficiency and a darker screen.

Thus, before we can construct higher resolution PDPs, we have to find a way around the luminous efficiency reduction problem. For this reason, our research has centered on achieving higher resolution and higher efficiency through an understanding of the ultraviolet light emission mechanism in a micro cell. It entails plasma measurements, to gauge the excited particle distribution, as well as computer simulations to perform a detailed analysis of the discharge phenomena, such as on how the particles that emit ultraviolet light are excited.

Development of a PDP with 0.3-mm pixel pitch

Thus far, our analysis of ultraviolet light emission in a micro cell has revealed that certain measures, such as increasing the gas pressure of a cell up to atmospheric pressure, could attain the enhancements listed below, even when using a 0.3-mm pixel pitch:

1. Fewer excited particles lost at the cell wall surface,
2. An excited-particle production efficiency equivalent to that of a conventional cell,
3. Energy-efficient discharge for generating excited particles.

These findings led to the establishment of guidelines for the realization of a brighter panel with enhanced resolution. This year's annual STRL Open House presented an exhibition of a prototype panel based on these findings (Figure 2).