If a patent claim already granted is limited by the patentee in the course of nullity proceedings, it is not possible to check whether the limited claim wording is now clear. With its decision on “joint tape”, the German Federal Supreme Court set standards for nullity proceedings with regard to patent claims.
Decisive decision of the Federal Supreme Court in Nullity proceedings
Neither the European Patent Convention (EPC) nor the German Patent law (PatG) provides for an examination of claims for clarity already granted. This also applies if the restriction is made for reasons of clarification and the version issued may have been unclear in some way, but the claims issued in each case have nevertheless been clearly disclosed to an expert.
This was already clarified by the Federal Supreme Court (BGH) in October 2015 in its so-called “Fugenband” decision (Case No. X ZR 11/13) and thus set standards for nullity proceedings with regard to patent claims.
The European patent in the focus of this case concerns a cold-processed joint tape which was originally granted with seven claims. The disputed patent was intended to produce a maximum quantity of bitumen for sealing, moving and adhering in road construction to a connecting flank in order to install a soft joint. In concrete terms, the patent was intended to provide a joint tape that was easy to process and at the same time guaranteed a tight seam seal.
Nullity proceedings and allegation of indistinct disclosure
Several points were at issue: firstly, the court had to clarify the meaning of the term “joint tape”, and the parties also disputed what qualifications the relevant expert had to have. Usually a fictitious “authoritative” expert is assumed for the interpretation of a patent and the assessment of patentability. The complaint was:
- the claim of the patent in dispute goes beyond the content of the application as originally filed and is not patentable.
- in addition, an object is claimed which is not so clearly and completely disclosed that an expert can carry it out.
The BGH stated: If the patent proprietor himself limits one or more claims in nullity proceedings, it should only be examined whether the subject matter thus defined goes beyond the original disclosure and thus inadmissibly extends the scope of protection. Further admissibility criterion according to Art. 84 p. 2 EPC, Sec. 34.3 No. 3 PatG in conjunction with Sec. 9.6 German Patent Ordinance (PatV), also whether the claim in the limited version was sufficiently clear and precise. These requirements also apply to the limited version of a patent claim.
No examination for clarity – not even in the case of amended patent claims
However, in the case of patent claims already granted or amended in opposition proceedings, an examination for clarity is prohibited because the patent proprietor may rely on a legal position once obtained, as long as there were no grounds for opposition or invalidity. The possibly unclear but nevertheless executable formulation of a claim itself does not constitute any such reason. Both the European Patent Convention (EPC) and the Patent law (PatG) would conclusively regulate grounds for opposition or invalidity, so that an examination point determined by a judge would inadmissibly interfere with the patentee’s protected legal position.
Authoritative expert and required description of execution
The BGH further states that the relevant expert is the one who is involved in the development and production of materials for seams and connections in road construction and in the sealing of joints in practice. This would require knowledge of material properties, but this could include both a road construction engineer and a construction chemist, even if the latter is mainly involved in the composition and use of building materials. The patent claim need not contain all the information necessary for the execution of the invention. It is sufficient if a general solution scheme is given to the expert. The court pointed out that terms can also be defined independently in the description of the patent and in this respect they are, to a certain extent, a patent encyclopedia.
Finally, the BGH defined the term “joint tape” used by the patent in dispute by interpreting the information on purpose, effect or function, which may be contained both in the claim itself and in the patent description. The definition also takes into account the corresponding leaflet of a road and transport research company as such, “with which a weather-related and mechanical resistance and tight production of seams and connections in road construction can be achieved”, which is attached laterally in a joint.
Change of material claims permitted in claims for use
Finally, the BGH recognised the patentability of some of the disputed patents, and the invention was also executable. However, two German patent specifications (K12 and DD 258 259 (K10)) were declared invalid without further substantive examination. At the same time, the court court declared the limited defense admissible by changing the substantive claims into usage claims. Because an inventor should receive protection for the new and not obvious use of a well-known product. And an examination of the patent claims as amended in claims for use was not admissible.
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