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2025 Week 43
When you overlay an international court like the UPC with an array of existing national courts, there are wrinkles that need sorting out. In Heraeus v. Vibrantz, the UPC Local Division Munich had to decide on how two national law issues should be folded into an assessment by the UPC: whether there was a secret prior use defence available, and the principle of res judicata.
The dispute and its backstory
Heraeus started a UPC infringement action against Vibrantz based on EP 3215288 B1. Vibrantz filed a counterclaim for revocation. But actually that was not the start. The forerunner of Vibrantz had started nullity (invalidity) proceedings against the patent in the German national court. Those proceedings had concluded in November 2023 with the decision that the patent was valid in amended form.
The invention is all about compositions for making electrical connections between components. The composition is placed between the electrical components and then sintered at about 200-280°C. Claim 1 as granted contains lists of chemical entities which can be ignored for now, and so an abbreviated form for the claim is this:
1. A metal sintering preparation which comprises
(A) 50 to 90 weight per cent of at least one metal selected from … , said metal being present in the form of particles having a coating … , and
(B) 6 to 50 weight per cent of one or more organic solvents selected from …
characterised in that
the mathematical product of the packing density … and the specific surface of the metal particles of the component (A) … is within the range from 40,000 to 80,000 cm-1.
Validity and res judicata
The counterclaim for revocation filed at the UPC by Vibrantz was based on grounds of sufficiency, novelty and inventive step. In the German nullity proceedings, only novelty and inventive step had been raised. The UPC decided that, to the extent that the UPC validity proceedings concerned the same patent, the same parties and the same grounds, then the UPC could not interfere with the German national court’s decision on validity. This is res judicata.
However, the court agreed that it could decide on the validity of the patent, based on the same grounds, in respect of other UPC states. Here, those states were France, Italy and Romania.
Also, because sufficiency had not been raised in the German national proceedings, the UPC decided that it could also decide on the validity of the patent in Germany on this specific ground.
The patentee had filed various auxiliary requests but in the end decided not to defend the claims as granted and retreated to the third auxiliary request, which had the same scope as the amendments upheld in Germany. The amendments to the claim were to change it to a use claim, to define the metal particles as flakes or having an irregular shape, and changing the parameter range to 50,000 to 80,000 cm-1.
The UPC looked at the insufficiency objection but decided that this was in effect just a disguised clarity objection to the breadth of the claim. So, even though this was available for all UPC states, the court dismissed the objection as not being substantiated by Vibrantz.
The claims were deemed novel over the available prior art and so the court turned to inventive step. As we have seen in various other decision from the Munich LD, the court used the problem-solution approach and decided that the amended claims were inventive. What was decisive here was the formulation of the objective technical problem based on the technical advantages shown by the Examples in contrast to the Comparative Examples in the patent.
Infringement assessment
The court decided that the relevant Vibrantz product was a literal infringement of the patent as amended. It was undisputed that Vibrantz manufactures and distributes these sintering pastes in Germany.
Secret prior use
In a first to file patent system, many countries recognise that there is a potentially unfair situation, in which a party is prevented by a patent from continuing with activities that they were doing in private before the priority date of the patent. The solution to this is to provide a statutory defence to patent infringement based on “secret prior use” – that the defendant should be allowed to continue with their activities from before the priority date.
At the UPC, this defence is set out in Article 28 UPCA:
Article 28
Right based on prior use of the invention
Any person, who, if a national patent had been granted in respect of an invention, would have had, in a Contracting Member State, a right based on prior use of that invention or a right of personal possession of that invention, shall enjoy, in that Contracting Member State, the same rights in respect of a patent for the same invention.
The cases that have considered this to date make it clear that this defence relies on the national law of the relevant country and only applies to that country. You can see that Article 28 UPCA does not even say what the “right of prior use” is.
Evidence of secret prior use in Germany
As you’d expect, the burden of proof to invoke this defence is on the defendant. What sets this case apart is the very detailed evidence that Vibrantz was able to provide to prove their prior use.
The German prior use defence requires the defendant to show that, before the priority date, they had already begun to use the invention or had made the necessary arrangements for its use.
Vibrantz provided evidence that they had formulated a sintering paste based on silver flakes, including one made with SF 30 flakes (as mentioned in the patent) and one with SF 70 flakes. The defendant had advertised these sintering pastes. Therefore the defendant had committed themselves to a specific formulation before the priority date and they continue to manufacture sintering pastes with the same formulation today. For the SF 30 flakes, the relevant parameter value for the claim is 60,390 cm-1. For the SF 70 flakes, the relevant parameter value is 71,838 cm-1. These both fall inside the range defined in claim 1 of the third auxiliary request.
The court looked carefully at the evidence provided. They were satisfied that the defendant regularly manufactured and sold these sintering pastes. It was not necessary to show that, before the priority date, the defendant was aware that the physical characteristics of the silver flakes met the requirements of the claim. The fact that they were inherently met was enough. However, the evidence did show that Vibrantz was aware that the sintering pastes produced a suitably strong bond, which is the same as the claimed benefit of the invention.
Therefore the court decided that the defendant has a right of prior use that covers Germany.
Infringement outside Germany?
The court decided that the patentee had not provided suitable evidence of infringement outside Germany. They had alleged that Vibrantz must distribute the same product into France and Italy at least, but had not substantiated this.
Therefore the court concluded that there was no evidence of infringing acts outside of Germany.
Outcome
So, even though the amended claims were valid and the defendant’s products fell inside the scope of the claims, the court decided that there was no infringement. In the round, this is a clear win for the defendant, but the court decided that the costs should be divided so that the patentee bears 60% and the defendant bears 40% of the total costs of the case.
