Sony has vowed to appeal against a US court ruling which found the electronics giant guilty of infringing the patents of a small US company. 

The legal row arose over the Dual Shock technology that Sony uses to make its controllers vibrate in time with the action of games.

A US district court dismissed Sony's appeal against the $90m award to Immersion, which claimed that its force-feedback technology has been used by the Japanese firm. 

"We still believe that we have not infringed on Immersion's patents," said a spokeswoman for Sony's SCE video game unit. 

The continuation of the legal battle could add further delay to the beleaguered PlayStation 3 console, which uses the Dual Shock technology. 

Sony has also suffered a setback in its bid to make Blu-ray the dominant future format. Disney had originally planned to show its support for the Sony-backed DVD format by only releasing its titles on Blu-ray.

However, Disney chief executive Bob Iger told Variety.com that the company is considering releasing some of its stock on the rival HD-DVD format. "We will probably publish in both formats," Iger said. 

Rumours suggest that Sony will announce its plans for the PS3 on Wednesday. It is expected that the company will confirm a launch date and pricing for the next-generation console.