Photo Source: DKEM
On June 2, 2026, the China National Intellectual Property Administration (CNIPA) issued a decision declaring both of two Wuxi DK Electronic Co., Ltd. (DKEM) patents (Patent Nos. ZL201180032359.1 and ZL201180032701.8) wholly invalid.
The patents share the same title: "Thick Film Paste Containing Lead-Tellurium-Lithium-Titanium-Oxide and Use Thereof in Manufacturing Semiconductor Devices." They are conductive silver paste patents originally held by DuPont de Nemours' Solamet photovoltaic paste business. DKEM gained control of the portfolio through its RMB 696 million acquisition of a 60% stake in Solamet Materials Science Co., Ltd. in May 2025.
The CNIPA panel ruled that both patents fail to comply with Article 26.4 of the Chinese Patent Law, meaning the claims are not supported by the description. According to the panel, a person skilled in the art could not determine, based on the patent descriptions, that all claimed technical solutions would achieve the effects described in the patents.
This decision is another case of CNIPA's increasing reliance on Article 26.4 (support by the description) in invalidation proceedings, raising the bar for patent drafting quality.
DKEM had used these two patents to launch six separate patent infringement lawsuits over the past five years, with claims in each case ranging from RMB 100 million to 200 million, for a cumulative claimed amount of RMB 1 billion.
In August 2021, Solamet Materials Science Co., Ltd., affiliated with DKEM, sued Changzhou Fusion New Material Co., Ltd. for infringement of both patents in the Suzhou Intermediate People's Court, filing two cases with RMB 100 million sought per patent. The parties reached a settlement in August 2022.
In November 2025, Zhejiang Suote Material Technology Co., a holding subsidiary of DKEM, sued Zhejiang Gonda Electronic Technology Co., Ltd. in the Zhejiang High People's Court for infringement of Patent No. ZL201180032359.1 alone, claiming RMB 200 million. It was Gonda that filed the successful invalidation actions against both patents.
In January 2026, DKEM filed two separate RMB 200 million lawsuits at the Jiangsu High People's Court against Jiangsu Riyu Photovoltaic New Materials Co., Ltd. and Suzhou iSilver Materials Co., Ltd.
In April 2026, DKEM sued Pharos Materials Co., Ltd. and its Shanghai branch in the Shanghai High People's Court for infringement of both patents, claiming RMB 200 million.
With both core patents invalidated, the legal and factual basis for all pending claims has effectively evaporated. Whether DKEM will appeal remains uncertain.
