On June 5, 2025, Samsung Display filed a lawsuit against TCL China Star Optoelectronics Technology (TCL CSOT) and its affiliates in the U.S. District Court for the Northern District of Texas, alleging infringement of three key patents related to OLED technology.

The three patents at issue are:

US11,594,578 ("578") – concerning the pixel arrangement structure of organic light-emitting display devices;

US7,414,599 ("599") – involving OLED display pixel circuits and driving methods;

US9,330,593 ("593")– covering cascade scan circuits and their application in OLEDs.

Notably, the first two patents (‘578 and ‘599) have already been upheld as valid in inter partes review (IPR) proceedings before the U.S. Patent Trial and Appeal Board (PTAB). The third patent (‘593) remains under review.

According to the complaint, Samsung Display accuses TCL CSOT—including its majority-owned subsidiary Wuhan China Star Optoelectronics Technology—of supplying infringing OLED panels to TCL’s parent company and to U.S.-based aftermarket parts sellers, including Ultimate Eshop and eTech Parts Plus. The panels in question are used in smartphones such as the TCL 10 Pro and TCL 20 Pro 5G, and some are sold as replacement parts within the U.S. repair market.

Samsung points out that these three patents were previously asserted in a Section 337 investigation before the U.S. International Trade Commission (ITC), where they were deemed valid. eTech Parts Plus was also named as a respondent in that case. While the ITC confirmed infringement, it declined to issue an import ban, shifting the dispute to civil litigation for damages and injunctive relief in federal court.

This case marks Samsung Display’s latest legal action against Chinese panel makers, following a previous lawsuit against BOE Technology Group.