Legal attack dog Rambus has suffered another blow to its memory technology licensing business after a US patent office appeals board declared three Barth patents invalid.
Reuters reports that the three Barth patents refer to PC memory controllers and have been used by Rambus to collect millions of dollars in licensing fees from HP, Nvidia and other suppliers. The appeals board cut two of them down in September last year and the third one fell on 24 January.
This decision comes after Rambus lost a near-$4bn lawsuit against Micron and Hynix Semiconductor in November 2011.
It is thought unlikely that Rambus will appeal the latest ruling as the patent officer examiner looking at it would not want to disagree with the appeals board. The overall effect would be to reduce Rambus' patent licence income stream.
Rambus is emphasising LED lighting and cryptography in its recent activities and may be preparing to gradually vacate the computer memory field, a strategy that would be loudly applauded by its memory licensees and bruised legal case opponents in that area. ®