Seoul Viosys v expert klein (CFI, 10 October 2024)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

In a decision of 10 October 2024 (UPC_CFI_363/2023), the Düsseldorf Local Division ruled on Seoul Viosys’s infringement action against expert e-Commerce and expert klein, based on EP 3 926 698 for a light emitting diode, and on the counterclaim for revocation brought by expert klein alone. The action succeeded and the counterclaim, though admissible, was dismissed: the Division granted an injunction for eight States, recall, definitive removal from the channels of commerce, destruction, information and damages in principle, without making enforcement conditional on security. The statements of principle are of practical interest: each jointly sued defendant remains an autonomous party, a counterclaim for revocation is assessed defendant by defendant, and making enforcement conditional on security calls for a case-by-case weighing for which the defendant must supply the facts. On the same day the same panel ruled on a related patent in UPC_CFI_483/2023.

Facts and procedure

The patent, a divisional of EP 2 757 598, protects a flip-chip diode with mesa-etched areas, a multilayer reflective electrode, an insulating layer and a current spreading layer. Seoul Viosys, supported by Seoul Semiconductor as intervener, targeted the flash components of Emporia “SMART.5” smartphones sold by both defendants and sought, among other relief, an injunction for eight States, recall, destruction, information and damages. Only expert klein counterclaimed for revocation, on the grounds of added matter and lack of inventive step. Seoul Viosys filed eleven auxiliary requests. Four further requests were not admitted by the judge-rapporteur on 1 July 2024, which the panel upheld on 5 August 2024 under Rule 333.1 RoP. The hearing took place on 5 September 2024.

The applicable law

The UPC’s jurisdiction rests on Article 32(1)(e) UPCA and Articles 24(4), 71a and 71b of the Brussels I recast Regulation, no opt-out being in force. Absent a preliminary objection, jurisdiction is accepted (Rule 19.7 RoP). The counterclaim is governed by Rule 25.1 RoP. Added matter is assessed under Articles 123(2) and 138(1)(c) EPC, and inventive step under the objective approach adopted in Sanofi v Amgen.

Question

What follows from one co-defendant’s failure to counterclaim, and does the patent, which also covers single-mesa diodes, extend beyond the application as filed?

Decision

A claimant may sue several defendants separately or together. Even when joined, the proceedings remain autonomous and one defendant’s acts neither benefit nor prejudice the others. Rule 25.1 RoP requires a counterclaim from each defendant contesting validity: expert e-Commerce, which filed none, is formally precluded from that line of argument, with no practical consequence as long as the Division does not separate the proceedings. Claim 1 requires at least two mesa-etched areas but also covers single-mesa diodes. The layers of the reflective electrode are defined by function, not material. Added matter was rejected: the application as filed discloses such configurations and presents coverage of the side surfaces by the barrier layer only as an option. Novelty was not disputed. Inventive step was upheld. As the Korean priority was not validly claimed, the relevant date is 17 May 2012. Starting from D3, the skilled person would find palladium in D5 as a material for the barrier layer. Since D5 teaches that silver and palladium give rise to almost no thermal stress, there was no reason to add a stress relieving layer between them. D2, alone or with D1, did not lead to the invention either, there being no reason to combine two self-contained embodiments without hindsight. Literal infringement was found (Article 25(a) UPCA): the defendants had not specifically contested the claimant’s technical explanation, which was therefore treated as undisputed (Rule 171.2 RoP), and the titanium, nickel, titanium, nickel stack qualifies as a composite stress relieving layer, the upper titanium layer acting as the barrier layer, what matters is the ratio between the expansion coefficients, not their exact values. Offering and selling give rise to a rebuttable presumption of use, import and possession. The operative part prohibits offering, placing on the market, using, importing and possessing the diodes in Austria, Belgium, Germany, France, Italy, Luxembourg, the Netherlands and Sweden, subject to a penalty of up to EUR 250,000 per infringement, and orders, for products delivered since 4 January 2023, recall, definitive removal from the channels of commerce and destruction at the defendants’ expense, together with information (Articles 63, 64, 67 and 68 UPCA). The costs of the action are borne by the defendants in equal shares and those of the counterclaim by expert klein. The value in dispute was set at EUR 500,000 and the ceiling for recoverable costs at EUR 56,000 for each of the two proceedings. The objection to immediate enforcement, based on the diode being a tiny fraction of the phone, failed for want of any specific harm. The requested security of EUR 5,000,000, ten times the value in dispute, was refused: it is for the defendant to set out the facts warranting security (Rule 118.8 RoP), and resellers barred from selling a single model had shown no irrecoverable loss. Enforcement requires the claimant to notify which part of the orders it intends to enforce and to file a certified translation.

Key points for practice

• Each co-defendant wishing to challenge validity must bring its own counterclaim or join a common one (Rule 25.1 RoP).
• Making enforcement conditional on security (Rule 118.8 RoP) calls for a case-by-case weighing. The defendant must first set out the facts that justify it, the claimant’s financial position being a relevant factor.
• A blanket denial of the opponent’s technical case is not enough: absent a specific challenge, the facts are treated as undisputed (Rule 171.2 RoP).
• Practical point: co-defendant resellers should consider a joint counterclaim so that each keeps its invalidity defence should the proceedings be separated.

Provisions applied

Agreement on a Unified Patent Court

Arts. 25(a), 32(1)(e), 63, 64, 67, 68, 69, 82 and 83(3)

Rules of Procedure

Rules 19.7, 25.1, 30.2, 118.5, 118.8, 152.2, 158, 171.2, 303.3, 333.1, 340 and 354.4

European Patent Convention

Art. 54, 56, 69, 123(2) and 138(1)

Regulation (EU) No 1215/2012

Arts. 24(4), 71a and 71b

Case law cited

NanoString v 10x Genomics, Court of Appeal, 26 February 2024, Kaldewei v Bette, Düsseldorf Local Division, 3 July 2024, Sanofi v Amgen, Munich Central Division, 16 July 2024, Mammut v Ortovox, Court of Appeal, 25 September 2024, Ballinno v Kinexon Sports, Court of Appeal, UPC_COA_328/2024, 26 August 2024, SodaStream v Aarke, Düsseldorf Local Division, 5 August 2024, Volkswagen v NST, Munich Local Division, UPC_CFI_514/2023, 23 April 2024

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.