Insights: EPO Board of Appeal aims to clarify the correct approach to claim interpretation when assessing patentability

In Opposition and Appeal proceedings at the EPO, the questions of when and how to turn to the description to interpret the claims can be the turning point for whether a Patent is revoked or maintained. In T 0169/20, the Technical Board of Appeal (“the Board”) discusses the legal provisions and case law that are relevant to answering these questions. While the Board’s discussion provides welcome input on issues of law, this decision does not provide concrete answers to these key questions.

Case at hand

In T 0169/20, the Board decides to revoke a Patent with claims directed towards packaged detergent compositions (dishwasher tablets). This Decision is relevant to all technical fields beyond dishwasher tablets, because the Board provides a detailed discussion of the fundamental principles of claim interpretation.

Claim 1 as granted included the expression “…the detergent composition having a fluid phase and containing a second container…”. A key issue relevant for the assessment of novelty and inventive step is whether this expression requires a restricted configuration, wherein the second container must be within the fluid phase; or whether other configurations are encompassed by the claim language.

As claim interpretation was in dispute, the Proprietor took the position that if the claim was ambiguous and there were doubts as to how the claim should be interpreted, the description should be relied upon to interpret the claims to resolve those doubts. According to the proprietor, there were also contradictory approaches in the jurisprudence of the EPO’s Boards of Appeal as to when and how the claims should be interpreted in the light of the description. Seeking to clarify this uncertainty, the Board discusses the relevant legal provisions and the case law that gives answers to these questions.

Legal provisions

The Board expresses disagreement with a body of case law according to which Article 69(1) EPC is applicable to the interpretation of the claims for the assessment of patentability. Instead, the Board endorses a different body of case law that views the provisions of Article 69(1) EPC as applicable only to the determination of the extent of the protection of the patent. The latter is relevant only for the assessment of infringement, or when examining whether post-grant amendments result in claim broadening contrary to Article 123(3) EPC.

The Board concludes that it is the provisions of Article 84 EPC and Rules 42 and 43 EPC which represent the appropriate legal basis for claim interpretation when assessing the patentability of an invention; and which provide a framework for deciding when and how to rely on the description to interpret the claims.

The Board’s discussion provides a welcome assessment of the legal provisions underpinning claim interpretation when assessing the patentability of an invention. However, it remains to be seen whether other Boards of Appeal will endorse this position or whether some Boards of Appeal will continue to diverge and rely on Article 69(1) EPC for assessing patentability. The importance of this issue may be felt by parties to Opposition and Appeal proceedings in future decisions if the legal provisions under Article 69(1) EPC and 84 EPC give lead to different answers on when and how we should turn to the description to interpret the patentability of claims.

When and how the description may be used

T 0169/20 reinforces that the description should not be used to undermine the primacy of the claims, which define the invention through the combination of stated technical features. Instead, T 0169/20 affirms that the description should only be used to interpret the claims in exceptional cases when this is both necessary and possible to do so.

According to the Board, the necessary support from the description arises in circumstances where there is a need to clarify the subject-matter of the invention or its technical context. Examples of this need may be the result of claims having ambiguous, unclear or relative terms such as “slightly smaller” or “low levels”, which are not further defined or understandable from the rest of the claims. Another example is where the technical context of the description is needed to arrive at the true meaning of the claim. In these cases, the description may support discarding alternatives that are formally encompassed by the words of the claims but are incompatible with how the invention works.

If exceptional circumstances occur so that support from the description to interpret the claims is necessary, the Board outlines that this support must also be possible. To fulfill this supporting role, the description can be relied upon to the extent that there is correspondence between the description and the subject matter of the claimed invention, so that the technical explanations in the description can serve to illustrate the meaning of the claimed features.

Outlook

The Board’s discussion establishes some welcome principles, but notably stops short of providing a set of specific steps that should be followed to apply the principles in practice.

While the Board considers that the practice of the EPO’s Appeals Boards as to when and how the claims should be interpreted in light of the description is “reasonably homogeneous” it is our view that this issue will remain a rich area of contest moving forward, because claim interpretation is often in dispute.

It is also noteworthy that in T 0169/20 the Board indicated that well known expressions such as “the patent is its own dictionary” and “the terms used in patent documents should be given their normal meaning in the relevant art, unless the description gives the term a special meaning” are misleading. Thus, T 0169/20 highlights once more the importance of effective drafting to minimize the chance for later interpretation disputes in Opposition and Appeal proceedings.