A federal jury ruled Apple (AAPL - Get Report) infringed on a University of Wisconsin patent when developing processors for some recent iPhones and iPads, the Journal reported.

The jury in U.S. District Court in Madison, Wis., found that the university's 1998 patent on improving efficiency in computer processors is valid and that Apple illegally incorporated the patent's technology in processors that help power some iPhones and iPads.

The jury hasn't yet ruled on damages. The university sought as much as $862.4 million, according to a court filing.