UPC legal test for assessing ‘added matter’ set

Laura Finn and Jane Bourke of Pinsent Masons commented after the UPC Court of Appeal confirmed a single legal test – that UPC judges will need to apply in relevant cases going forward – for assessing whether an amendment to a patent contains ‘added matter’ in a case involving a dispute over a patent relating to light emitting diodes (LEDs).

According to the court, UPC judges must determine what information a person skilled in the relevant art would derive directly and unambiguously from the entirety of the patent application as filed if viewed objectively and on the date of filing with their general knowledge. It added that, in this context, implicitly disclosed objects are also to be regarded as part of the contents of a patent application where they are clear and unambiguous from what is expressly mentioned.

The Court of Appeal’s ruling was issued in a dispute between patent owner Seoul Viosys Co. Ltd (Viosys) and two companies, expert e-Commerce GmbH and expert klein GmbH (together, Expert).

Before the Düsseldorf local division (LD) of the UPC, Viosys had successful claimed that the SMART.5 32 GB smartphone that Expert marketed, which contains a single LED chip, infringed its patent. Viosys had also been successful in defending a counterclaim that Expert had raised that its patent was invalid.

However, Expert challenged the Düsseldorf LD’s decision before the Court of Appeal. This included challenging findings of the LD pertaining to the validity of the Viosys patent. Central to this appeal were its claims that not all features of Viosys’ patent had been disclosed by Viosys and that the Düsseldorf LD had been wrong to consider otherwise.

In this case, Viosys’ patent was a divisional patent, meaning it was split off from an earlier parent patent application of broader scope. With its appeal, Expert essentially claimed that Viosys’ patent application introduced ‘added matter’ beyond that which had been disclosed in the contents of the original parent application. Divisional patents can be invalidated if it is found that the application contains added matter.

Viosys’ application for its divisional patent contained not only patent claims – these being the claims included in patent applications that go to the heart of what the invention is and what it achieves – but also descriptions of the claimed invention and drawings in support of those patent claims.

The Court of Appeal, recalling earlier UPC case law on how patent claims should be interpreted, confirmed that the descriptions and drawings in the patent must be consulted as explanatory aids, and not only to resolve ambiguities in the patent claim. It went on to consider that Viosys had made claims in its divisional patent application that extended beyond what was disclosed in the parent patent application. Based on this finding on ‘added matter’, the divisional patent was considered invalid. In light of the invalidity of the patent, it was not necessary for the Court of Appeal to consider infringement.

Bourke said: “In assessing added matter, the Court of Appeal applied the same test that lower divisions of the UPC have applied in previous decisions. The test is the same as the ‘gold standard’ test applied by the European Patent Office though, interestingly, the Court of Appeal made no reference to the EPO test or to any previous EPO decisions in its ruling.”

“The Court of Appeal adopted a narrower construction of the claim than the Düsseldorf LD and reversed what could be regarded as a pro-patentee approach to added matter by the Düsseldorf court,” she said.

Finn added: “The speed at which the proceedings progressed from initiation to the Court of Appeal decision is noteworthy. The infringement action was initiated on 13 October 2023, with the Court of Appeal’s decision being issued on 2 October 2025. The entire process took just under two years, which is remarkably quick for complex patent litigation. While the proceedings were initiated in the early stages of the UPC when its caseload was lighter, the case involved several procedural complexities and applications. Its quick progression highlights the efficiency and speed of the UPC.”

“One of the aims of the UPC is to speed up patent proceedings in Europe, and it will be interesting to see whether it can maintain this efficient pace as its caseload grows,” Finn said.