Court revives Microsoft co-founder’s patent suit against Apple, AOL, Google and Yahoo

A US appeals court on Wednesday revived part of a patent lawsuit brought by Microsoft co-founder Paul Allen against AOL, Apple, Google and Yahoo, saying a lower court's finding that the tech companies didn't infringe one of its patents was incorrect.

The patent, held by Allen's Interval Licensing, relates to the ubiquitous pop-ups that offer usability ideas, organising audio/visual for display in a browser or alerting users to items of current interest.

The Court of Appeals for the Federal Circuit said that Chief Judge Marsha Pechman of the federal district court in Seattle had made an "erroneous" interpretation of the patent in 2013 and it sent the case back to her for further hearings.

Circuit Judge Raymond Chen, however, agreed with Pechman's invalidation of certain claims made by Interval, declaring them as ambiguous.

Interval Licensing is the patent-licensing arm Interval Research Corp, a Silicon Valley research entity funded by Paul Allen, which shut down in 2000.

Microsoft co-founder Paul Allen started Interval Research in 1992. During the 1990s, the company filed for several user-interface related patents that were primarily intended to improve a computer user's online experience.

When Interval closed operations, the patents were transferred to Vulcan Patents LLC (presumably another Paul Allen company) and then to Interval Licensing which remains a Paul Allen company.

Interval Licensing sued the tech companies in 2010 for allegedly infringing four of its patents, although only two became the subject of the appeal. It said they infringed the patents through products and software that use pop-up notifications.

Allen and partner David Liddle founded Interval Research in 1992. It employed over 110 scientists and engineers and was granted 300 patents during its existence, according to court documents.