It said an initial determination by an Administrative Law Judge of the US International Trade Commission found that one Cirrus patent was unenforceable because prior art was not disclosed to the US Patent and Trademark Office.
However the determination also found that three Wolfson audio digital-to-analog converters infringed another Cirrus patent and recommended a limited exclusion order against their importation into the US. Wolfson said this will have no effect on its business because two of the products were made obsolete in early 2004 and the third product was modified to remove the disputed feature.
In October 2003, Edinburgh, Scotland-based Wolfson had to delay its IPO to rewrite its prospectus after Cirrus filed the patent infringement claim.
