Hunan Tiandiren Law Firm, represented by He Yongxing, Director of Tiandiren Intellectual Property Committee,invalidation of a core invention patent held by Nitto Denko Corporation, a world-leading functional material and polarizer manufacturer. The National Intellectual Property Administration of China (CNIPA) issued a decision declaring all claims of the patent invalid. This landmark ruling breaks the patent barrier erected by the overseas giant in China’s optical film processing sector, lifting core intellectual property shackles for domestic display and flexible electronics, optical adhesive industries.

I. Patent Holder: Global Materials Giant Nitto Denko with Full Industrial Chain Patent Layout in China

Established on October 25, 1918 and headquartered in Osaka, Japan, Nitto Denko Corporation is listed on the Tokyo Stock Exchange (Stock Code: 6988). As of March 31, 2024, the Group operated 89 subsidiaries worldwide with a combined workforce of 27,426 and consolidated net sales of JPY 915 billion in FY2023. With a century-long focus on polymer functional materials, it ranks as the global absolute leader in polarizers, optical adhesive films and FPC flexible circuit boards, consistently listed on Forbes Global 2000 and Clarivate Top 100 Global Innovators. Its product portfolio covers display components, semiconductors, optical adhesives, automotive materials and medical supplies.

Nitto Denko has built large-scale production bases across China including Suzhou, Chengdu, Shanghai and Xiamen. Its OLED polarizer base in Chongzhou, Chengdu launched production in 2025, projected to generate annual revenue exceeding RMB 4 billion upon full capacity. Its UV light curing and film lamination core underpin mass production of polarizers and optical protective films. The disputed patent in question is its foundational core patent deployed to restrain the development of domestic manufacturers.

Filed in 2018 and granted in 2020, the patent fully covers the entire manufacturing process of laminates and related dedicated production equipment, widely applicable to LCD/OLED polarizers, electronic protective films, automotive decorative films and precision component lamination. It served as a core asset for Nitto Denko to build a patent blockade in China’s optical processing industry, long restricting mass production and technological iteration of domestic film manufacturers. The company also rolled out a global patent layout for this technology, filing over a dozen patents in Chinese Mainland, China's Taiwan region, Japan, South Korea, Vietnam and most territories obtained grants, alongside over a hundred patents covering integrated processes globally.

According to public information, the Ministry of Commerce added Nitto Denko to the Dual-use Items Export Control Watch List in February 2026. Its material technology exports and domestic patent layout have drawn sustained attention from the industry and regulators. The full invalidation of its core patent further reshapes fair competition within China’s optical materials market.

II. Full Trial Process: Complete Evidence Chain Proves Lack of Inventiveness

On January 22, 2026, Hunan Tiandiren Law Firm filed a patent invalidation request with CNIPA, arguing that all claims of the disputed patent failed to meet the statutory grant requirements under the Patent Law of the People’s Republic of China, and submitted multiple foreign prior patent documents and professional adhesive industry textbooks as evidence of prior art and common general knowledge.

The case went through formal acceptance, multiple rounds of written statements by both parties, oral hearing and cross-examination. The panel reviewed the technical solution, comparison with prior art and technical inspiration in three core dimensions item by item:

1. Core technical conception already disclosed in prior art
Through exhaustive retrieval, the attorney located a Japanese patent fully disclosing the patent’s core "paste first, then cut" process (applying adhesive film first, patterning cutting, stripping redundant areas and reinforcing adhesion), whose overall technical route highly overlaps with the disputed patent and serves as the closest prior art reference.

2. Distinguishing technical features carry obvious technical inspiration
Prior comparative documents disclosed mature UV light curing and irradiation adhesion reinforcement solutions. A person skilled in the art could easily replace traditional thermal pressing with UV curing to avoid product offset and poor precision caused by physical compression. Cutting and zone stripping are conventional film processing techniques without non-obvious innovation. The attorney supported this conclusion with ample evidence.

3. All dependent patents lack inventiveness
Additional technical limitations specified in the patent including UV curing formula, adhesion value range, large-size substrates, multi-unit batch processing and dedicated equipment were proven by the attorney to lack prominent substantive features and notable technical progress. CNIPA fully accepted these arguments.

Ultimately, CNIPA ruled that Claims 1-10 of the disputed patent as an integrated technical solution failed to meet the inventiveness standard stipulated by the Patent Law, and fully declared the patent right invalid in accordance with the law.

III. Three Major Industrial Breakthroughs Brought by the Ruling

1. Dismantles overseas core process patent barriers and expands domestic substitution space
Domestic OLED, LCD polarizer and flexible electronic industries are accelerating localized development. Japanese firms including Nitto Denko and Sumitomo have long built patent moats for underlying lamination technology, restricting domestic manufacturers’ capacity expansion via patent litigation and licensing fees. Nitto Denko holds over 114,000 global patents, among which 9,000 are invention patents filed in China alone, forming a tight intellectual property blockade. Full invalidation of this laminate processing patent drastically cuts domestic manufacturers’ production line licensing costs and infringement litigation risks, speeding up large-scale substitution of domestic polarizers and optical adhesives.

2. Sets benchmark case for domestic enterprises to counter overseas patent monopolies and provides replicable rights defense template
This case demonstrates a feasible path for domestic firms to fight cross-border patent monopolies: precise retrieval of global prior art documents, sorting industry common general knowledge, multiple rounds of written responses and technical oral arguments to build a rigorous invalidation evidence chain and achieve full claim invalidation. It delivers a replicable rights protection model for China’s display, polymer materials and precision film sectors, proving domestic market players can lawfully revoke unstable foreign granted patents through official intellectual procedures to safeguard fair market competition.

3. Validates the fairness of China’s intellectual property examination and standardizes cross-border patent competition
CNIPA’s trial strictly followed China’s Patent Law standards, objectively accepting Chinese and foreign prior art patents and industry reference books without bias due to the patentee’s status as a multinational corporation. The case embodies China’s dual intellectual protection principle: protect legitimate innovation while restraining monopolistic unstable patents, prohibiting foreign enterprises from leveraging intellectual property strategies to claim excessive protection and restrict domestic industrial growth, and standardizing fair competition between Chinese and foreign optical material enterprises.

IV. Conclusion

The full invalidation of Nitto Denko’s core invention patent stands as a landmark case where domestic entities counter overseas material giants’ patent monopolies, marking the first Nitto Denko patent fully invalidated in China. Against the backdrop of accelerated independent substitution in domestic display and flexible electronics, this ruling lifts critical intellectual property restrictions on the whole industry. It also proves that with a complete Chinese intellectual property examination system, domestic market participants can lawfully break foreign technical patent blockades and push the polymer material industry toward a new stage of fair, innovative competition.

As Japanese and South Korean functional material giants continue filing numerous underlying process patents in China to raise manufacturing costs via licensing and lawsuits, Hunan Tiandiren Law Firm will keep delivering full-chain legal services including patent risk screening, invalidation defense and infringement response for domestic optical and electronic material enterprises, continuously clearing monopolistic foreign patents lacking inventiveness and safeguarding the independent and controllable development of China’s polymer and display optical industrial chains.