Boeing's comma drama: Commas and taking the description into account when construing a claim (T 1127/16)

It is not only the choice of words that matter in patent claim interpretation. As the recent decision in T 1127/16 shows, grammar can be similarly important.  In this decision, the lack of a comma in a claim led to a successful added matter objection against Boeing's patent EP1798872. Caught in the inescapable trap of added matter that cannot be deleted without unallowably broadening the claim, the patent was found invalid on appeal. However, aside from the obvious lesson to be scrupulous in your claim drafting, the decision in T 1127/16 is also worth a read for the Board of Appeal's comments on the primacy of the claims over the description for determining the scope of protection, as was also recently discussed in the High Court's application of the doctrine of equivalents (IPKat). 

The importance of commas

The patent in question (EP1798872) in T 1127/16 related to a method of handling communications between a ground-based computer and an aircraft. The granted claim specified a process for selecting a preferred transmission network for the communication. The absence of a comma in one of the features meant that the step could be interpreted two ways. The ambiguity caused by the lack of comma is a classic linguistic peculiarity of English grammar (and also recently ignited yet further Brexit-related debate). In this case, a comma was needed to delineate a subordinate clause, a related but not identical issue to the use of Oxford commas. 

In the case in question in T 1127/16, one feature of the method claim comprised the provision of a list. The subsequent feature in the claim was not separated from the list step by a comma. The subsequent feature could thus be construed as either forming part of the provided list, or as forming a second independent step. Given the absence of the comma, the Opposition Division (OD) construed the claim as requiring the features to be run together. Since the OD found no disclosure of this combined feature in the application as filed, the patent was found invalid for added matter (Article 123(2) EPC). 

The IPKat hastily flying away
from the comma drama at the EPO

The Board noted that English does not have clear rules governing the use of commas. However, the Board determined that if the patentee had intended the relevant features to be separated, a comma would have been necessary in order to "even suggest" the separation to the reader (r. 2.6.4).

The Board of Appeal further found that a skilled person could not be expected to "speculate as to other possible meanings which might result from inserting commas at various places", as this would place undue burden on the reader. Looking solely at the claim language, therefore, the Board of Appeal agreed with the OD that the claim should be construed as requiring the features to be run together. 

The claims, not the description, define the scope of protection

On appeal, the patentee argued that a skilled person reading the claim would consult the description in order to resolve the linguistic ambiguity in the claim. In doing so, the patentee argued, it would become clear to the skilled person that the method comprised identifying the most preferred network available as a separate step.

The Board of Appeal was not convinced by the patentee's arguments. The Board noted the often quoted T 190/99, according to which a "patent must be construed by a mind willing to understand not a mind desirous of misunderstanding" (Case Law of the Boards of Appeal II.A.6.1). However, the Board did not consider the case law as requiring consultation of the description as soon as any ambiguous feature occurs in the claim (r. 2.6.1):

"According to such a logic, an applicant (patent proprietor) could then arguably dispense with providing a clear and unambiguous formulation of claim features, e.g. during the grant proceedings, in order to be able to fall back on a more description-based interpretation at will during a subsequent opposition proceedings"

The Board of Appeal thus confirmed that a claim should essentially be read and interpreted on its own merits: 

"... the description cannot be used to give a different meaning to a claim feature which in itself imparts a clear, credible technical teaching to the skilled reader [...] Otherwise third parties could not rely on what a claim actually states".

In the case in question, the Board of Appeal thus considered the pertinent question as being whether the claimed feature was meaningful and plausible from a technical point of view. In finding no technical reason for the claimed feature not to make technical sense, the Board of Appeal agreed with the OD that the claims was invalid for added matter (Article 123(2) EPC). The Board further rejected auxiliary requests in which the claims were amended to remove the possibility of the unwanted interpretation. However, these requests were rejected as broadening amendments, and thus not permitted post-grant (the "inescapable-trap"). 

Final thoughts

The contents of the description can be influential in questions of infringement. In the recent High Court case Illumina v MGI ([2021] EWHC 57 (Pat)), Mr Justice Birss (as he then was) found lack of infringement by equivalence in view of a strict definition of a term in the claim provided in the description (IPKat). Mr Justice Birss observed in Illumina v MGI that a limiting definition of a feature in the description, limits the scope of the claim. This observation appears at odds with the EPO case law, according to which the claims should be read on their own merits.  The decision of the Board in T 1127/16 makes it clear that the description cannot be used to give a different meaning to claim language that is prima facie clear. The Board's statement that "otherwise third parties could not rely on what a claim actually states" is one of the main objections lodged against the broad doctrine of equivalents adopted by UK judges.