A U.S. District Court judge in San Diego ruled that Microsoft Corp. must pay Alcatel-Lucent $511.6 million for infringing on two patents, marking the latest move in a 5-year-old patent scuffle between the two companies.

In April, a jury awarded Paris-based Alcatel-Lucent $357.7 million in damages from Microsoft after a trial in U.S. District Court.

The jury had found that the world’s largest software maker infringed on an Alcatel patent that covers how software users select a calendar date from a menu in certain programs, including Microsoft Outlook and Windows Mobile.

The jury also awarded Alcatel-Lucent $10.4 million from Microsoft after finding the software maker infringed on an patent related to the use of a stylus on a tablet computer.

Late Thursday, Judge Marilyn L. Huff denied Microsoft’s request that she reconsider those findings, and she raised the amount of damages due Alcatel-Lucent. The amounts now include prejudgment interest to compensate for how long it took to resolve the matter.

“We are disappointed that Judge Huff denied our request for a new trial,” said Microsoft spokesman David Bowermaster, in an e-mailed statement. “We plan to appeal the rulings against us. We are confident that the damages award against Microsoft will not be sustained on appeal.”

Huff also upheld the jury’s decision that Microsoft’s video encoding technology doesn’t infringe on a third Alcatel-Lucent patent. Bowermaster said the company was pleased with that decision.

In April, the jury also found that PC maker Dell Inc. infringed on the stylus-related patent. In the Thursday order, Huff affirmed that Dell must pay damages of about $70,000 to Alcatel-Lucent, including prejudgment interest.

“We had always believed we had a strong case and are pleased that the judge agreed that the jury’s thoughtful verdict was well reasoned and supported by the evidence presented during the more than monthlong trial on these two patents,” said Alcatel-Lucent spokeswoman Mary Lou Ambrus in an e-mailed statement.

This case, which considered three patent infringement claims against Microsoft and two against Dell, was one of several stemming from claims Lucent Technologies Inc. filed in 2003 against PC makers Gateway Inc. and Dell Inc. over technology developed by Bell Labs, Lucent’s research arm.

Microsoft added itself to the list of defendants, saying the patents were closely tied to its Windows operating system.

France’s Alcatel bought Lucent last year.

All the original claims now either have been tried or been dismissed, but Alcatel-Lucent is currently appealing the resolution of one of those original claims.

Another U.S. District Court judge in San Diego decided in 2007 that Microsoft need not pay $1.5 billion in damages, reversing a jury’s finding that Microsoft infringed on one of the French company’s digital music patents.