Rambus has had another of its patents declared invalid by the US Patents Office on the grounds of prior art which made the innovations described in the Rambus patent look ‘obvious’.
The invalid patent is one of three which have all now been found invalid.
The three patents were relied on in lawsuits against Nvidia, HP, Broadcom, Mediatek, STMicroelectronics, Micron and Hynix.
Last year Broadcom and Nvidia settled lawsuits with Rambus on the assumption that the three patents were valid.
In November, Rambus lost a case against Micron and Hynix. Since then the Rambus share price has fallen from around $18 to $8.
Collectively the three patents are called the ‘Barth’ patents