| NEC Wins Japan Patent to Drive Plasma Display Panels
May 29, 1998 (TOKYO) -- NEC Corp. said it has been granted a
Japanese patent on technology for controlling images on plasma
display panels (PDPs).
|A PDP display operates by repeating electric discharges. These
are a data-writing discharge that writes data to the addressed
cells and �ignites� them; a sustained discharge that emits
light in the addressed cells; and a data-erasing discharge that
erases remaining electric charges in the cells for the next
NEC was awarded a patent for two claims: (1) to secure ignition
of the cells, it lengthens the data-discharge time or raises
discharge voltage and compensates for uneven discharge voltage;
and (2) to limit ignition-time differences among the cells, it
controls the data-erase discharge, thus neutralizing the charges
in the cells, which eliminates cell malfunctions.
The company said these technologies are necessary to display fine
images on PDPs.
NEC confirmed that major PDP makers, such as Fujitsu Ltd. and
Matsushita Electronics Corp., are using the same technologies.
PDP makers are cooperating with each other to build up the PDP
market. NEC will soon request royalties for the patent from other
producers, company officials said.