Samsung SDI has filed a lawsuit against Japanese rival Matsushita Electric Industrial in the U.S., seeking the invalidation of the flat panel maker's patents, according to a report in FT.com.

The suit was filed earlier this month in the U.S. and is the latest move in a long dispute between the companies over basic intellectual property over plasma display panels.

According to the report, the two groups entered negotiations in 2004 after Matsushita claimed that Samsung SDI was infringing its patents. They however failed to reach an agreement and broke off the talks in late 2005.

Samsung SDI then fired the first salvo in the U.S. with a lawsuit that was quickly denied by Matsushita, who counter-sued, again in a U.S. court.

In the latest move, Samsung is said to be seeking a U.S. court ruling that the patents are invalid, to ensure that it does not have to pay royalties to its Japanese rival.

Earlier this month Samsung SDI Co. Ltd disclosed that it would invest $751 million to build a PDP plant that would begin operation in May 2007.

The South Korean group said its fourth PDP line would be located on a 99,000 square meter site in the southeastern industrial city of Ulsa and will have an annual production capacity equivalent to 3 million 42-inch PDPs. The plant will also bring Samsung SDI's annual PDP production capacity to 7.32 million units, the company said.

In January, Matsushita Electric Industrial said it would invest $1.6 billion to build a fourth PDP plant in Hyogo Prefecture, in a joint venture with Toray.