Gibson Guitar has launched another federal lawsuit - this time claiming that Harmonix, MTV Networks and Electronic Arts are violating one of its patents in Rock Band.
The case relates to the same virtual-reality patent involved in the existing lawsuit Gibson filed against six major retailers which sell Activision's Guitar Hero game.
Gibson says that by developing, promoting and distributing Rock Band - which has been a big hit in the US - Harmonix, MTV Networks and EA are infringing the patent.
Harmonix was quoted on Reuters has saying that the lawsuit was "completely without merit" and it planned to defend it vigorously.
Harmonix also developed the first Guitar Hero game and was later bought by MTV. EA publishes Rock Band.