Shozo Umeda

Discharge-time lag in a plasma display—Selection of protection layer (γ surface)

The discharge-time lag in an ac plasma display panel was studied and the discharge phenomena in the cells were considered. As a result, it was confirmed that time lag characteristics are unique in ac-driven capacitively coupled discharge elements and that such characteristics have a decisive effect on the dynamic characteristics. It was further clarified that the secondary emission coefficient γ of the protection layer determines the time lag characteristics and it is an important determining factor of the dynamic characteristics. As a result of the study of the effect of γ, it was possible to confirm that high γ leads to high performance and, accordingly, MgO is appropriate as protection-layer material.

A highly stabilized AC plasma display

Achieving overall stability of the ac plasma display/ memory device is vital to solving major problems to secure maintenance-free operation in its practical use. The stability improvement reported in this paper has been achieved by improving driving waveforms for the panel. The main improvements were: finding an address-pulse shape suitable for the panel characteristics, applying a proper address sequence, and the use of an addressing method free from half-select failure. These techniques have enabled us to obtain a wide operating margin in character-display application.