TCL EUROPE v Corning (CFI, 24 February 2026)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

In a decision of 24 February 2026 (UPC_CFI_337/2025), the Munich Central Division held unfounded TCL Europe’s revocation action against Corning’s EP 3 296 274 B1, which concerns a downdraw process for alkali-free glass sheets fined with tin, in force in France and Germany (paragraphs 3 and 10). Every ground examined failed: added matter, insufficiency, lack of novelty and lack of inventive step starting from D19 and D20. The decision is of interest for the weight it gives to the interdependence of features in a combined composition and process claim.

Facts and procedure

The patent is a divisional of EP 1 899 275 (published as WO 2007/002865, D2), the mention of grant was published on 26 April 2023 (paragraphs 2 and 3). TCL Europe brought the action on 22 April 2025, alleging lack of novelty and inventive step, insufficiency and added matter (paragraphs 1 and 5). Corning sought maintenance of the patent as granted or, in the alternative, on twenty auxiliary requests (paragraph 7). The hearing took place in February 2026.

The applicable law

The action falls under Art. 65 UPCA and Art. 138(1)(a) to (c) EPC, read with Arts 54, 56, 76(1), 83 and 123(2) EPC. On inventive step, the division applied the Court of Appeal’s approach in Amgen v Sanofi and Meril v Edwards (paragraphs 108 to 119).

Question

Is the claimed process, which combines downdraw forming, a defined glass composition and tin fining without arsenic or antimony, sufficiently disclosed, novel and inventive, and is it supported by the application as filed?

Decision

On construction, « alkali-free » means a total alkali content of at most 0.1 mol% (paragraph 23), the claim covers any downdraw process, including fusion (paragraph 25), the absence of purposeful use of arsenic and antimony tolerates traces (paragraph 31), the features are interdependent (paragraphs 34 to 37).

Added matter was rejected, the features being disclosed in combination in the application as filed (paragraphs 40 to 65). Disclosure is sufficient: Examples 1 to 43 are working compositions and the claimant did not show undue burden (paragraphs 66 to 84). Novelty was upheld: D9 does not directly and unambiguously disclose the downdraw process, and D11 requires values to be selected from broad ranges (paragraphs 85 to 106).

On inventive step, the objective problem is to provide a more environmentally friendly process for making alkali-free glass sheets suitable for AMLCD displays without costly finishing (paragraphs 120 to 123). D19 is a realistic starting point but gives no pointer to dropping arsenic and antimony, and its MgO teaching points away. Combining it with D17 or D15 does not lead to the solution (paragraphs 125 to 141). Starting from D20, neither Example 15 nor Example 10 leads to the invention, and the Swedish office report that treats the differences separately reflects hindsight (paragraphs 142 to 157). D27, focused on float processes, does not suggest tin fining in a downdraw process, even combined with D19 or D15 (paragraphs 158 to 164), and D11, D13, D14 and D16 change nothing (paragraphs 165 to 167). A judgment of the Supreme People’s Court of China on a related patent is irrelevant, without any need to rule on its late filing, and the auxiliary requests need not be examined (paragraphs 168 to 172).

The order dismisses the revocation action and orders TCL Europe to bear Corning’s costs, no ground of equity requiring otherwise (paragraph 173). The value in dispute, set by the judge-rapporteur at EUR 6,250,000, corresponds to a ceiling on recoverable costs of EUR 600,000 (paragraph 174).

Key points for practice

• Where claim features are interdependent, treating them separately is hindsight (paragraphs 34 to 37 and 142 to 157).
• The burden of showing a reasonable expectation of success lies with the party attacking validity (paragraphs 108 to 119).
• An isolated prior art example designed for another purpose does not anticipate a process it does not directly and unambiguously disclose (paragraphs 92 to 94).
• Practical point: against a claim combining composition and process, the attack must show why the skilled person would adjust the linked parameters together, not one by one.

Provisions applied

Agreement on a Unified Patent Court

Art. 32(1)(d), Art. 65, Art. 69(1) and Art. 83(3)

Rules of Procedure

Rules 17.3, 42 and 118.5

European Patent Convention

Arts 54, 56, 69, 76, 83, 123, 138

Regulation (EU) No 1215/2012

Arts 24(4), 71a and 71b

Case law cited

NanoString v 10x Genomics, Court of Appeal, 26 February 2024, Insulet v EOFlow, Court of Appeal, 30 April 2025 (UPC_CoA_768/2024), Brita v Aquashield, Munich Local Division, 22 August 2025, Baussmann v Raimund Beck, Munich Central Division, 20 November 2025, NJOY v Juul, Paris Central Division, 5 November 2024 (UPC_CFI_309/2023), GXD-Bio v Myriad, Munich Local Division, 19 December 2025, Abbott v Sibio, Court of Appeal, 14 February 2025, Amgen v Sanofi, Court of Appeal, 25 November 2025, Meril v Edwards, Court of Appeal, 25 November 2025, Expert v Seoul Viosys, Court of Appeal, 2 October 2025, Mammut v Ortovox, Court of Appeal, 25 September 2024

Related decisions

• TCL Europe v Corning, 1 December 2025, earlier decision in the same proceedings.

Prepared by Dhenne Avocats from the official decision, consulted on 10 October 2026. The database is updated every week, on Friday. Only the official text is authoritative.