An International Guide to
Patent Case Management for Judges

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5.5.1 Claim construction

According to Section 14 of the Patent Act and Article 69 of the EPC, the scope of protection of a patent is determined by the patent claims, whereby the description of the patent and (if available) the drawings are considered for the interpretation of the claims. Different from other jurisdictions, it is not admissible to use the files of a grant procedure as interpretation material. Conversely, prior art mentioned in the description of the patent can be used for interpretation purposes as well as opposition or nullity decisions.57

Patents are construed from the perspective of the so-called average person skilled in the art on the filing date or priority date of the patent. The person skilled in the art is defined as an imaginary person with professional training or qualifications (e.g., a skilled worker, master or engineer) and practical experience of the kind usually gained by those who have worked in the operational or industrial practice of relevant companies in the field to which the teaching of the patent belongs.

Patent protection cannot be derived from the patent description or the drawings alone: a technical teaching that is exclusively described there (both in terms of an extension or a limitation of the claim) but that is not reflected in the patent claims is not covered by the patent.58 Conversely, the claim must always be interpreted, not only if the wording of the claim is unclear, to determine the technical meaning associated with the wording of the claim.59 This is mandatory for the simple reason that the patent specification is its own dictionary for the terms used in it, and, therefore, only by referring to the description can information be gained about what the claim means and intends to protect with a certain wording.

In principle, the claim, description and drawings form a coherent unit and must be interpreted in a way such that contradictions do not arise unless contradictions are irreconcilable, in which case the patent claim prevails over the description or the drawings. Embodiments mentioned in the description must therefore give reason to ask whether it is possible to interpret the features of the main claim such that all variants described as being in accordance with the invention are also covered by the wording of the claim. Only if such an interpretation is precluded by the specific wording of the claim is there room for an interpretation that an embodiment disclosed in the description is not covered by the claim. However, such cases are rare exceptions.60

Furthermore, the technical meaning or function of the individual feature and the extent to which it contributes to the invention laid down in the patent claim (a so-called functional interpretation) should always be considered.61 However, in the case of spatially, physically or substance-defined features, this should not be reduced to the mere function of the feature. Rather, the feature should be interpreted in a sense that is consistent with the spatially, physically or substance-defined nature of the feature.62 The function-oriented interpretation may exceptionally give rise to a situation wherein the meanings of terms used in different contexts in the patent claim do not necessarily mean the same thing but are instead defined according to the technical functions given by each individual context.63 This may also result in a feature having different content than the corresponding feature in another publication in the state of the art.64

In addition, it must also be ensured that the wording of the claim is fully understood and that the necessary infringement argument is therefore also made with regard to those implicit features that follow only indirectly from the other features of the claim. The following aspects also need to be taken into account when interpreting the features of the claim:

  • References in the claim do not limit the protection to an exemplary embodiment.
  • It cannot be concluded from the absence of a feature in a drawing (that it is part of the technical teaching) that the feature in question is not present.
  • A claim feature may merely express a technical matter of course for the skilled person in the art.
  • Features in a patent claim that do not leave any gaps to be filled on the basis of the self-evident knowledge of the average person skilled in the art are to be interpreted in such a way that, from the entirety of the claim features, a suitable subject matter for the purposes of the invention results.
  • Most often, the term “in particular” introduces an optional feature. However, this might not be the case when the text following the phrase contains an exemplary concretization of a more general feature that has been mentioned in advance.
  • The terms “contains” and “comprises” allow additional components besides those explicitly mentioned in the claim; the terms “consists of” and “is composed of” are to be understood as an exhaustive list such that no additional components are allowed.
  • The designation of a component in the plural may suggest the possibility of the use of a generic designation; however, this only applies if there are positive indications in the description that an object with the component as singularly designated is also intended to be in accordance with the invention.
  • An obviously false designation (falsa demonstratio) in the claim may be corrected based on the description and the drawings.
  • Patents need to be interpreted by considering the description and the drawings. It should not influence the interpretation of the patent claim whether this results in an inadmissible extension patent beyond the content of the application. Patent interpretation and added matter are two different issues that should not be mingled.65 The same is true with regard to patentability: a patent should not be interpreted narrowly just because that would allow its delineation from prior art.