By Blake Brittain

Feb 18 (Reuters) - Ericsson ERICb.ST has sued Acer 2353.TW in Delaware federal court, seeking a declaration that the Swedish telecommunications company does not infringe Acer patents related to 4G and 5G wireless standards.

Ericsson said in a complaint made public on Wednesday that Taiwan-based Acer broke its obligation to license its standard essential patents on fair terms and had threatened to sue for patent infringement.

Spokespeople for Acer did not immediately respond to a request for comment on the lawsuit. An Ericsson spokesperson declined to comment.

Standard essential patents cover technology necessary for devices to implement standards like 4G or 5G wireless, and are required by international standards-setting organizations to be licensed on fair and reasonable terms. Wireless communications standards have been at the heart of many patent disputes involving tech companies including Ericsson and Acer as well as Apple, Samsung and others.

Acer sued Ericsson customers Verizon, T-Mobile and AT&T in Texas federal court last month, accusing them of infringing its patents through their use of Ericsson's cellular base stations. The new lawsuit said Acer's allegations against the companies "made clear that Acer intended to take action against Ericsson’s base station equipment, creating an imminent threat of a patent infringement suit by Acer against Ericsson."

Ericsson said that it has met with Acer but been unable to resolve the companies' dispute. It asked the court to rule that it did not infringe Acer's patents and that Acer breached its duty to negotiate in good faith, in addition to requesting an unspecified amount of monetary damages.

The case is Ericsson Inc v. Acer Inc, U.S. District Court for the District of Delaware, No. 1:26-cv-00176.

For Ericsson: Nicholas Mathews and Erik Fountain of McKool Smith

For Acer: attorney information not immediately available

(Reporting by Blake Brittain in Washington)

((blake.brittain@tr.com; +1 (202) 938-5713))