Less than a month after it sued rival PC manufacturer Acer over five alleged patent infringements, HP has added another four patents to the list.
On 27 March, HP filed a complaint against Acer in a Texan court, which claimed that Acer was infringing patents covering technologies such as read/write optical drives, power management in notebooks and digital bus arrangement.
As with that complaint, the new lawsuit — filed on Thursday — seeks to stop Acer from importing and selling its PCs in the US. The four patents this time 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 International Trade Commission.
"The filings were necessary because HP believes Acer has been importing into the United States and selling computer products that use HP's patented technologies without permission. 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.
The first patent (6,691,236) involved in the new lawsuit relates to "portable computer systems that conserve power by altering the performance of the video graphics controller depending on the system's power source or battery condition". The second (6,029,119) covers the management of multiple cooling options in a personal computer; the third (5,535,415) the ability to allow "concurrent bus operations to increase computer efficiency"; and the fourth (6,894,706) "various methods and apparatuses for determining the resolution of graphics received from a computer and scaling it to match the fixed resolution of a display device".
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 could offer no comment on the lawsuit at the time of writing.