A new referral on claim interpretation: G 1/26 heads to the Enlarged Board

A new referral to the Enlarged Board of Appeal (EBA), G 1/26 ("Coated steel strips"), is set to test just how far the description can be used when interpreting claims for the purposes of Article 123(2) EPC (basis for amendments).

Claim interpretation has become something of a theme for the EBA recently. Just a year ago, it handed down its decision in G 1/24, holding that the description and drawings “shall always be consulted to interpret the claims”.  A little over a month later, we saw the referral of G 1/25, questioning the need to conform the description with amended claims. The decision on that referral is expected this summer. Now we have our third referral in this vein in as many years in the form of G 1/26, where the EBA is asked whether an added matter attack can be overcome by using the description to interpret (limit) the claims. 

Background
Much of the controversy comes from the EPO’s infamously strict approach to claim interpretation, where the claims have often been interpreted in isolation, and the description and drawings only referred to in cases where the claims were unclear. This approach was recently reviewed in the referral of G 1/24, where the EBA was asked to decide to what extent the description can be used to interpret the claims, particularly where the description provides an interpretation that goes against the ‘normal meaning’ of the claims. 

The EBA held in G 1/24 that the description and drawings must “always be consulted” when interpreting claims, but it stopped short of explaining what that actually means in practice. As we mentioned in a recent article, how far ‘consultation’ goes, and what it permits, remains very much up for debate. 

It could seem that different Boards have pulled in somewhat different directions when applying
G 1/24, with some Boards consulting but not necessarily following the description as such
(T 1561/23) and others finding claims to be so broad as to lack novelty when read in light of the description (T 1849/23). However, a general trend appears to be that while disclosures in the description may well broaden the scope of the claims, it is much harder to successfully argue that disclosures in the description impart a narrower than ‘normal’ meaning on claim terms. 

The question of how to interpret the claims is particularly important given the EPO’s equally strict prohibition on added matter. According to Article 123(2) EPC, a European patent or application may not be amended in such a way as to add subject matter not disclosed in the application as filed. Whether a claim adds matter, can depend of course on how the language of the claim is interpreted, and this is the focus of the latest referral in G 1/26.

Facts of the case
The case underlying this latest referral involves an appeal against the Opposition Division’s decision to maintain EP3587104 in amended form. The claims relate to a pre-coated steel strip, comprising a base steel which claim 1 defines as including various components by weight (based on total weight). The claim was amended during prosecution of the application to introduce a unitless parameter: “wherein the ratio of titanium to nitrogen is in excess of 3.42”. However, the description of the patent referred to this ratio only as a weight ratio. The key question in the appeal is whether this amendment adds matter. 

The opponent argued that, since no unit for the ratio was mentioned in the claim, the claim encompassed other ratios which were not disclosed in the application as filed, such as a stochiometric ratio. On that basis, the amendment should be considered an impermissible generalisation. The proprietor on the other hand argued that since the description referred only to weight ratios, the wording of the claims must also be interpreted as referring to a weight ratio. 

In its referring decision, the Board noted that the question of added matter therefore turned on whether, and to what extent, the description is used to interpret the claim when assessing basis in the application as filed. To that end, the Board identified three competing approaches in the case law.

• First, there is a restrictive approach, under which all technically plausible interpretations of a claim must be considered. If any one of these extends beyond the content of the application as filed, the claim adds matter. Under this interpretation, the Board considered claim 1 as amended would add matter. 
• The second approach is to focus on the wording of the claims in isolation, rejecting attempts to read in limitations from the description. This interpretation would also lead to a finding of added matter in the referred case. 
• Third, there is the more holistic approach where the patent is read as a whole. On this basis, the description can clarify, or even limit, the meaning of claim features. Applied here, this would mean interpreting the Ti/N ratio as a weight ratio based on the description, thereby avoiding added matter. Interestingly, although the Board did not mention it, this is the approach preferred by the Unified Patent Court (UPC), in line with the UPC Court of Appeal’s decision in NanoString Technologies v. 10xGenomics. In that decision, it was held that “the description and the drawings must always be used as explanatory aids for the interpretation of the patent claim”.

As the Board noted in its referral, it is clear that these three approaches can produce very different, indeed opposite, outcomes. Rather than choosing between the competing strands of case law, it has asked the EBA to step in and provide clarification.

Admissibility
The Board also devoted considerable attention to whether the referral would be admissible at all. Traditionally, the EBA has taken a strict approach to this requirement, normally only accepting a referral in the case where the patent would have been maintained on all other grounds (essentially to prevent unnecessary referrals). In this case, the referring Board did not consider the other grounds in the appeal, finding it ‘impractical and inefficient’ to do so. This led the Board to also refer a question regarding whether the referral itself was admissible (see question one below). 

The referred questions
Board of Appeal 3.3.05 therefore referred the following questions to the EBA:

• 1. May a decision be considered to be "required" for the purposes of Article 112(1) EPC, if the referring Board demonstrates that the point of law in question arises out of the context of the case pending before it and, in the circumstances of the proceedings, it is reasonable for the Board to examine it and decide on it next?
• 2 (a). Does the fact that the claims are the starting point and the basis for assessing the patentability of an invention generally preclude a feature which is only disclosed in the description or the drawings of a patent from being read into the meaning of a granted claim, in particular if this leads to a restrictive reading of terms used in the claim?
• 2 (b). If the answer to question 2(a) is no: is claim interpretation the result of both reading the claims and consulting the description and drawings as a unitary process and does the claim being the starting point and the basis for assessing the patentability rule out only those interpretations which can be derived from the patent as a whole but would clearly contradict the general technical understanding of the terms used in the claim?
• 3(a). When assessing compliance with Article 123 (2) EPC, must a term used in a claim be assessed against all interpretations that make technical sense to the skilled reader on the basis of the claim alone?
• 3 (b). If the answer to question 3(a) is no: is it sufficient that only the interpretations of the subject-matter of the claim established against the background of the patent specification as a whole are directly and unambiguously derivable from the application as filed?

Our take
There is a sense in which G 1/26 feels like an inevitable sequel to G 1/24, with the EBA being asked to answer the question that G 1/24 left open. That decision ran to only 12 pages and left many of the practical issues of claim interpretation undecided. That said, while it might be argued that there has been some divergence between Boards on what it means to ‘consult’ the description, it seems unlikely that the EBA could have meant only ‘look at but ignore’ as in the second approach discussed by the referring Board. It therefore seems that any divergence is really between the EPO’s historically restrictive approach and the UPC’s more holistic one. If the referral is accepted, we could therefore see some welcome alignment between the EPO and UPC on the issue. 

It will also be interesting to see whether the EBA considers this referral admissible at all, particularly if it regards its guidance in G 1/24 as sufficiently clear already. Either way, G 1/26 looks set to provide the next chapter in what is becoming a steadily expanding body of case law on claim interpretation.

We will be reporting as this case continues, so make sure to follow us on LinkedIn for the latest news and developments. For more information, please contact Chris Lindsay, Tom Turner, or your usual Abel + Imray advisor.