Germany's Federal Patent Court invalidated an Apple photo-management patent because Steve Jobs showed how the technology worked during a keynote months before the company applied for the patent in Europe.

The Munich-based court invalidated the Apple patent Thursday, said court spokeswoman Ariane Mittenberger-Huber in an email Friday. The validity of the patent was contested by the German subsidiary's of both Google-owned Motorola Mobility and Samsung Electronics.

The patent, which covers the bounce-back effect in a photo gallery, was partly annulled because the relevant priority date of the application was June 2007, after Jobs demonstrated the technology on stage in January 2007 during the first iPhone keynote, she wrote.

The main part of the patent was declared invalid because of prior art, she said. Prior art is typically documentary evidence that ideas or designs for which patent protection is sought are not original.

"As a matter of principles even an inventor's own public demos can be held against his own patents if they took place before the filing of an application," said Mittenberger-Huber.

Apple probably forgot an important difference between U.S. patent law that was in effect at the time and the patent laws in Europe, wrote Florian Mueller, a legal consultant who has been an adviser for tech companies including Oracle and Microsoft, and participated in oral proceedings in Germany. In 2007, U.S. patent applicants had a 12-month grace period in which what they made public about their technology would not constitute prior art, Mueller wrote on his blog.

Europe, however, never had such a grace period, said Kevin Mooney, a U.K.-based intellectual property lawyer who specializes in patent litigation, in an email.

"This historical difference between U.S. and European patent law has been well known for many years and has provided many opportunities to invalidate patents in Europe based upon premature articles, presentations etc. in the U.S.," he wrote, adding that this is "basic knowledge for patent lawyers."

"What is surprising is that Apple did not take suitable precautions as most sophisticated companies, being aware of the risk, usually have strict guidelines to avoid premature disclosure," Mooney said.

While the patent was rendered invalid in Germany, it has been successfully used in Europe. In 2011, for instance, a Dutch court granted Apple an E.U.-wide sales ban on the Galaxy S, SII and Ace based on the same patent. Apple also won an injunction against Motorola Mobility in the regional court of Munich in 2012.

Apple can still appeal the case within a month after the formal notification of the judgment to the Supreme Court, Mittenberger-Huber said.

Apple and Google declined to comment. Samsung and Motorola did not respond to a request for comment.