Japan's Pioneer has filed suit in the United States against Samsung SDI and Samsung Electronics for what it says are patent violations of its plasma display-panel technology. South Korea's Samsung SDI, the world's top plasma display-panel maker, said it plans to file a countersuit, although no date has been set. Pioneer's move, announced Monday, is the latest in a series of intellectual property suits and countersuits between Japanese companies and their Asian rivals as they seek to maintain a technological edge. "We decided that litigation was necessary to protect our intellectual property," Pioneer spokesman Kesanobu Yamagishi said of the suit, the first time the company has litigated for a possible patent infringement. Samsung SDI, which is also in patent spats with Japan's Matsushita Electric Industrial and Fujitsu, had been in talks with Pioneer since April 2005 about possible licensing agreements, but the talks fell through, Yamagishi said. Pioneer is asking for a court order to stop Samsung SDI's sales of plasma display panels and compensation for alleged violations of a patent for electrode configuration boosting display quality and another patent for a manufacturing step that increases display brightness.