Originally published on IPKat.
Claim interpretation is the current hot-topic at the EPO, specifically the extent to which the description should be taken into account in claim interpretation. The EPO has recently taken a hard line against using the description to narrow the meaning of clear language in the claims. There is, however, another line of recent EPO case law which has taken a similarly hard line on requiring the description to be amended in line with the claims. According to these Board of Appeal decisions, inconsistencies between the claims and the description would confuse the skilled person over how to interpret the claim language. To this Kat, these lines of case law are incompatible: either clear language in the claims should be interpreted in view of the description, or it should not, the EPO cannot have it both ways. To complicate things further, there is also mounting Boards of Appeal case law finding the contrary position on description amendments, i.e. that the description does not have to be amended in line with the claims.
It is thus becoming increasingly clear that a referral to the Enlarged Board of Appeal on claim interpretation is necessary to harmonise Boards of Appeal case law. In this context, the recently published Board of Appeal decision in T 1924/20 adds further weight to the line of Boards of Appeal case law that the description is irrelevant to the interpretation of otherwise clear claim language.
Construing the claims to incorporate a functional effect from the description
The decision in T 1924/20 is interesting for its rejection of an approach to claim interpretation whereby functional effects mentioned in the description may be incorporated into the claims via judicious construction of the claim language. The patent in question (EP2898704) related to a hearing aid that could be worn for several months or years without being taken out, and a method of manufacturing hearing aids. The problem to be solved by an “extended wear” hearing aid of this type was how to protect the hearing aid’s electronics from prolonged exposure to ear fluids. The patent was opposed for lack of inventive step.
The Patentee’s defence relied upon a claim construction based on the description of the patent. The granted claim specified a method of manufacturing a hearing aid comprising encapsulating the electronic module. The Patentee argued that this encapsulating step would necessarily lead to a reduction in the chance of moisture reaching the electronics of the device, and that the prior art did not disclose such a step. In support of their claim interpretation the Patentee pointed to passages in the description of the patent stating that the position of the electronics module in the hull of the device “reduced the chance of moisture breaching the capsulation”.
The Board of Appeal was not convinced by the Patentee’s arguments. The Board of Appeal argued that the passages of the description cited by the Patentee could not change the interpretation of the claim Particularly, the Board of Appeal dismissed an approach to claim interpretation that incorporated limitations from the description, finding that ‘a skilled reader of a patent claim would, for many reasons, interpret the claims based essentially on their own merits […] This is because the “subject-matter of the European patent” (cf. Article 100(a) EPC) is defined by the claims and only by them’.
The Board of Appeal also cited with approval the reasoning from the Boeing catastrophic comma loss case (T 1127/16). In Boeing, the Board of Appeal found that it was not possible for the patentee to have recourse to the description in order to overcome an added matter objection resulting from the loss of a single comma from the claims. The Board of Appeal particularly found in Boeing that the description could not be used to change the meaning of otherwise clear language in the claims. The Board of Appeal in the present case agreed with this reasoning, finding that “when interpreting the claims, the description and drawings cannot be relied on as a sort of fall-back or supplementary-guidance tool for filling up gaps or for resolving inconsistencies in a claim to the patent proprietor’s advantage”.
The appeal was therefore set aside and the patent revoked. Interestingly, the Patentee did not seek to rescue the patent by incorporating the functional limitation into the claims.
Analysis
T 1924/20 is yet another Board of Appeal decision to add to the pile of recent case law finding against a role for the description in claim interpretation (see also T 0821/20). In all of these cases, the decisions have gone against Patentees arguing for a different interpretation of the claims based on the description in order to overcome an added matter or inventive step objection. The EPO has thus taken a hard line against the particular use of the description to narrow the meaning of the claim language. It will be interesting to see whether in infringement actions, a similarly hard line will be taken against the attempts of alleged infringers to narrow the claims in arguments of non-infringement.
