Expert e-Commerce GmbH & Expert klein GmbH v. Seoul Viosys Co., Ltd.

This case concerns an appeal (UPC_CoA_764/2024 and UPC_CoA_774/2024) before the Court of Appeal of the Unified Patent Court, decided on October 2, 2025, against a decision of the Local Chamber Düsseldorf of October 10, 2024.

The appellants, Expert e-Commerce GmbH and Expert klein GmbH (part of the expert retail group operating in consumer electronics in Germany), were defendants in the first instance. The respondent, Seoul Viosys Co., Ltd., a global supplier of LEDs and Vertical Cavity Surface Emitting Lasers, was the plaintiff and proprietor of the patent in suit. Seoul Semiconductor Co., Ltd. intervened in support of Viosys.

The patent in suit, EP 3 926 698, concerns a light-emitting diode (LED), particularly a flip-chip type LED with improved light output. The patent is a divisional application originating from European patent application 17165501.2 (which led to EP 3 223 320), itself a divisional of European patent application 12832213.8 (published as EP 2 757 598 A2). The parent application is the European regional phase of Korean PCT application KR2012/007358 (published as WO 2013/039344 A2). The patent claims priority from Korean applications filed in September 2011, February 2012, and May 2012. The patent was granted on January 4, 2023, and is in force in Germany, Austria, Belgium, France, Italy, Luxembourg, the Netherlands, and Sweden.

The core legal issue was whether claim 1 of the patent contained an inadmissible extension of subject matter (unzulässige Erweiterung des Gegenstands). The Court of Appeal established the legal principle that an inadmissible extension occurs when the subject matter of a granted claim extends beyond the content of the application as originally filed. To determine this, the court must ascertain what information a person skilled in the art would directly and unambiguously derive from the application as filed, using their general knowledge viewed objectively and as of the filing date. Implicitly disclosed subject matter, i.e., that which clearly and unambiguously follows from what is expressly stated, is also considered part of the content. For a patent derived from a divisional application, this requirement applies to each prior application, meaning the granted claim 1 must not extend beyond (1) the disclosure of the originally filed application of the patent in suit and (2) the disclosure of the original PCT application that entered the regional phase and constitutes the parent application of the divisional.

The dispute centered on feature 5.2 of claim 1, which requires that the lower insulating layer has openings arranged near an edge of the substrate that allow the first conductivity type semiconductor layer to be exposed through them in the mesa-etched areas. The appellants argued that this feature was not disclosed in the original applications, particularly in Figures 24 to 26 of the parent application, which showed only a single mesa embodiment. The respondent Viosys argued that Figure 24 disclosed feature 5.2 because it was sufficient that openings were located near the edge, even if they were arranged within the mesa area.

The Court of Appeal rejected Viosys's interpretation, finding that feature 5.2 requires that no further mesa (or mesa area) be located between the outer openings and the outermost edge of the substrate. Openings arranged within the mesa surface do not satisfy this requirement. The court further noted that if openings extended to the edge of the substrate, the edge would have a very fragile and breakable jagged side, and at least some material must exist beyond the outer openings to prevent breakage—a point Viosys did not convincingly contest.

Based on these findings, the Court of Appeal concluded that claim 1 contains an inadmissible extension of subject matter. Since claims 4, 5, 6, and 9 depend on claim 1, they were also invalid for the same reasons. The auxiliary requests all related to embodiments with a single mesa and therefore could not lead to a valid claim. Other invalidity arguments raised by expert klein did not need to be addressed.

Given the invalidity of the patent, the court did not need to rule on the alleged infringement. As the losing party in the appeal proceedings, Viosys was ordered to bear expert's costs for both the appeal and the first instance proceedings, for both the revocation counterclaim and the infringement action.

The final decision: The Court of Appeal set aside the first instance decision in full, declared claims 1, 4, 5, 6, and 9 of the patent invalid with effect for all designated territories, rejected all of Viosys's requests in the infringement action, and ordered Viosys to pay the costs of both the appeal and first instance proceedings.