In a decision made public on Wednesday, the patent office upheld the validity of a patent held by the University of California and its Eolas Technology spinoff. In 2003, a jury awarded more than US$500 million in damages to the university and Eolas, but an appeals court this year partially upheld Microsoft's appeal, saying the company should be able to present evidence that similar inventions predated Eolas' patent application.
A University of California spokesman said on Thursday that the patent office's ruling essentially says that the earlier work should not invalidate the Eolas patent.
"It is the second time that the patent office has thoroughly vetted the patent claim," UC spokesman Trey Davis said. "We're pleased that the ruling confirms our position all along."
Microsoft, meanwhile, expressed displeasure with the decision.
"This is very disappointing news, but we remain committed to seeing this case through to a successful resolution," a Microsoft representative said on Thursday.
Eolas and the university filed suit against Microsoft in 1999, alleging that the way Microsoft's Internet Explorer uses plug-ins and applets infringes on an early-1990s patent.
