David Shannon Nvidia Corp.

The action, known as filing an action closing prosecution, follows preliminary rejection of the claims earlier this year by the PTO, Nvidia (Santa Clara, Calif.) said.

A spokesperson for Nvidia said all 17 claims were found to be invalid due to the existence of prior art references. One of the patents was deemed to have been patented in a previous Rambus patent, which is not allowed, the Nvida spokesperson said. The PTO's order was not made available to the public, according to the Nvidia spokesperson.

A spokesperson for Rambus (Los Altos, Calif.) said in such cases the patents remain valid and enforceable as originally issued until the reexamination proceedings are concluded, including all appeals. One study indicates that it takes up to six-and-a-half years for re-exam claims to work their way through the U.S. PTO, the spokesperson said. After that, the cases can be appealed to the Federal Circuit and possibly to the U.S. Supreme Court, the spokesperson said.

"This continues our string of victories against Rambus patents in the U.S. PTO," said David Shannon, NVIDIA executive vice president and general counsel, in a statement. "We believe these patents are invalid and are confident that a similar decision will be made on the patents that continue to be examined."

There are still eight claims in two other patents involved in the case, Nvidia said. The U.S. PTO preliminarily rejected these claims, but has yet to issue a final determination on them.

"This is a very long process, and the patents remain valid during the whole process," the Rambus spokesperson said in a written statement. "Of all the re-exams that have been filed pertaining to our patents, no final determinations have issued."

The ITC said in December 2008 it would investigate Nvidia and some Nvidia customers for possible infringement of Rambus patents, following a complaint filed by Rambus. In June, Rambus asked an administrative law judge at the ITC to terminate the investigation of Nvidia on four of the nine patents that Rambus initially claimed that Nvidia infringed.

In January, Nvidia asked the PTO to reexamine the Rambus patents involved in the ITC case.

On Monday, Rambus announced that a San Francisco Superior Court judge recommended that Rambus' antirust case against memory manufacturers be coordinated with a Tessera Technologies Inc. antirust case against Hynix Semiconductor Inc. Judge Richard A. Kramer also recommend that the Rambus case be assigned to the San Francisco Superior Court, Rambus said.

Kramer made clear that he would recommend coordination so long as it does not delay the commencement of the Rambus antitrust jury trial, which is set to being Jan. 11, 2010, Rambus said.