Less than a month after it sued rival PC manufacturer Acer over five alleged patent infringements, Hewlett-Packard has added another four patents to the list.
On March 27, HP filed a complaint against Acer in a Texas court, which claimed that Acer was infringing patents covering technologies such as read/write optical drives, power management in notebooks and digital bus arrangement.
The areas of focus of the four new patents range from thermal management to video control, and are being disputed through a complaint filed with the same court and a separate complaint lodged with the US International Trade Commission.
"HP will continue to take action to protect its intellectual property against unauthorised use. HP respects the intellectual property rights of others, and we expect the same treatment in return," a statement from HP said.
HP claims to hold more than 6,000 patents related to PC technology, "including power management, DVD editing and a broad range of other features that improve computer efficiency and enhance the user's computer experience."
Figures released by analysts at Gartner in January indicated that Acer remained the fastest-growing PC manufacturer in the world for the third year running. Acer has the fourth-highest market share, behind HP, Dell and Lenovo.
Acer was unavailable to comment on the lawsuit at press time.
David Meyer reported for ZDNet UK from London
