Guitar Hero, the popular video game franchise that has sold more than 14 million units in North America alone, has been a boon for video game producer Activision. The controller that looks like the Gibson SG has made many a would-be rock star blister their fingers with reckless abandon is instantly recognizable across many demographics.

But what looked like a friendly relationship between Gibson and Activision has gone sour as the guitar maker claims the video game company has violated a patent held by the former. Informed of the claim by letter in January, Activision countered by filing suit in federal court to declare Gibson's patent invalid. Activision's initial position rests strongly on Gibson's delay in claiming infringement. Guitar Hero has been available for three years.

Tags: Activision, business, Gibson, Guitar Hero, Law