Patent attorneys are very particular about grammar and agonise at length over the best form of words in a patent specification. A recent case illustrates why they are right to be so particular.
We can all laugh at how a misplaced comma can change a lovable herbivorous bear to a hit and run killer:
A panda is an animal that eats, shoots and leaves.
but for the patentee on the wrong side of the European Patent Office (EPO) Board of Appeal decision T 1473/19, it was no laughing matter when the lack of a comma shot down their patent.
Background of the case
A patent was granted for a joint for a CT scanner comprising a rotary joint body. At the grant stage, the EPO Examining Division proposed an amendment to the claims that supposedly inserted the feature that the rotary joint body has a free inner bore, while retaining the requirement that the rotary joint body holds the capacitive data link. However, the claim amendment proposed by the EPO was:
“said body having a free inner bore holding a capacitive data link”.
In post-grant opposition proceedings, an Opponent and the Patentee differed on how the amended claim should be interpreted.
The Opponent submitted that the skilled person would have understood from the amended expression in the claim that the body has a free inner bore and that this bore holds a capacitive data link – ‘interpretation (a)’. The Opponent objected that the amendment introduced subject-matter extending beyond that of the application as filed because the original application did not disclose this configuration.
In contrast, the Patentee argued that the claim as amended was ambiguous and could also mean that the body has a free inner bore and, additionally, the body holds a capacitive data link – ‘interpretation (b)’. The Patentee argued that faced with this ambiguity, the skilled person would turn to the description and drawings to resolve whether interpretation (a) or (b) was correct. As the description only disclosed the body holding the capacitive data link, interpretation (b) was correct.
The Opposition Division sided with the Patentee, that is that the skilled person would consider interpretation (b) to be the correct interpretation in the context of the description. Consequently, the Opposition Division held that the amendment did not add matter over the original disclosure.
The Findings of the Board of Appeal
When interpreting the claim, the Boad considered that: “In the absence of any comma and any coordinating conjunction separating the various terms, the person skilled in the art, on a plain reading of this expression, would simply consider the subject governing each present participle [“having, “holding”] to be the noun group ["said body", "a free inner bore", "a capacitive data link"] immediately preceding it, following the usual rule that modifiers are generally placed next to the word they modify. In this way, the person skilled in the art would arrive at the construction that the body has a free inner bore and that this bore holds a capacitive data link”. Thus, the Board held that interpretation (a) is the plain meaning of the claim as granted.
The Board affirmed that the description and drawings should be taken into account when interpreting the claims, but stressed that the description does not have the same weight as the claims. The Board went on to consider whether in the light of the description the skilled person would nevertheless adopt interpretation (b). In this case, while the description and drawings do not disclose the inner bore holding the capacitive data link, neither do they preclude interpretation (a), for example, by suggesting that having the inner bore hold the capacitive data link is technically nonsensical or incompatible with the invention. Thus, the ordinary meaning of the claims takes primacy.
Furthermore, the Board affirmed there is no principal that the claims must be interpreted in a manner which avoids them extending to subject matter not disclosed in the application as originally filed.
As the claims are directed to a rotary joint body where it is the inner bore that holds the capacitive data link, and that subject matter was not disclosed in the application as filed, the patent should be revoked.
No way back
The Patentee presented various options to remedy the situation, such as inserting commas in the claim:
“said body, having a free inner bore, holding a capacitive data link”.
However, the Board considered such revisions extend the scope of protection to subject matter not previously covered by the granted claims, i.e. a joint where it is the body that holds the capacitive data link as opposed to the free inner bore. Such an extension of protection after grant is not permitted by the EPO and is thus an impermissible amendment post-grant.
The Board also rejected attempts by the Patentee to correct the wording of the claims, sticking to the established case law that forbids corrections to the text of a patent specification once granted.
For the Patentee this was an inescapable trap – while the wording of the claim was found to extend beyond the disclosure of the original application; changing the wording to something that was disclosed was no longer possible. Thus, the patent was revoked.
This decision shows that the strict approach of the EPO can lead to the loss of a patent for seemingly minor lapses in grammar. It is crucial that claim amendments made in prosecution not only find clear basis in the application as filed, but have the intended meaning.
It also highlights the importance of carefully and critically reviewing any amendments proposed by the EPO. The response to the Notice of Allowance (Communication under Rule 71(3) EPC) is the final opportunity to make changes to the specification and thoroughly reviewing the specification proposed for grant, especially any revisions proposed by the EPO Examining Division, is a vital and necessary step.
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