In a recent decision from the European Patent Office (EPO), T 1473/19, the Board of Appeal has revoked a patent for added subject matter due to its interpretation that claim 1 lacks basis in the description of the application as filed. This case highlights the importance of precise claim drafting and the potential pitfalls when there are discrepancies between the claims and the description of the invention.
The Invention
The patent in question, EP 2,621,341 B1 (owned by Schleifring GmbH), aimed to improve contactless rotary joints, particularly those used in CT scanners, by minimizing interference between the rotating transformer and the data link. Claim 1 as granted included the clause that the contactless rotary (CR) joint comprised:
“…a rotary joint body (200) of a plastic material, said body having a free inner bore holding a capacitive data link…”
Opposition
During first instance proceedings before the Opposition Division, the Opponent, Siemens Healthcare GmbH, asserted that claim 1 added matter on the basis that the application as filed only disclosed a CR joint wherein the ‘rotary joint body’ holds the capacitive data link, whereas, in contrast, the claim as granted required that it was the ‘free inner bore’ that holds the capacitive data link. In other words, according to the Opponent, there was no basis in the application as filed for a free inner bore holding the capacitive datalink because the only embodiments described related to said datalink being held in the rotary joint body.
The Patentee counter-argued that a person skilled in the art would have immediately identified an ambiguity and that from a technical point of view, a free inner bore, i.e. an empty space, was itself not able to hold something. It is only what surrounds this empty space, i.e., the surrounding body, that could hold the capacitive data link. They went on not argue that a person skilled in the art would therefore have consulted the description and the drawings to resolve this ambiguity. Since the description of the patent only disclosed that it was the body which held the capacitive data link, the skilled person would have necessarily concluded that claim 1 could only be interpreted in this way. For this reason, the Patentee asserted that there was no added subject matter.
The Opposition Division agreed with the Patentee, deciding that claim 1 should be interpreted in the context of the description. On this point, they noted that the description only disclosed that the body had a free inner bore to accommodate a patient, and that it was the body itself which held the capacitive data link. The claims were therefore found not to contain added matter, and the patent was maintained as granted.
Appeal
The Opponent appealed, arguing that because the language of claim 1 as granted was clear, recourse to the description was not needed. The Patentee essentially put forward the opposite argument, i.e., claim 1 was ambiguous and, therefore, a person skilled in the art would have consulted the description and drawings to interpret the claim.
Interpretation
The Board considered whether, and to what extent, the description should be taken into account for the interpretation of a patent claim. The question asked was should the claim be interpreted such that:
(a) the body holds the capacitive data link (which has clear basis in the application as filed);
or that:
(b) the free inner bore holds the capacitive data link (which does not have basis in the application as filed).
The Board of Appeal noted differing case law on the extent to which the description and drawings should be used to interpret the claims. For example, the Board referred to T 197/10 and T 1127/16 which support that the description should only be used to interpret claim features that are otherwise ambiguous (and should otherwise be interpreted on their own merit). However, it also referred to T 2365/15, T 1167/13 and T 2773/18 which support that the description and drawings should be used to interpret the claims.
Two provisions in the EPC were considered relevant to claim interpretation:
- Article 69 EPC(1): The extent of the protection conferred by a European patent or a European patent application shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims; and
- Article 84 EPC: The claims shall define the matter for which protection is sought. They shall be clear and concise and be supported by the description.
Previously, in T1279/04, the Board of Appeal found that Article 69 EPC relates to claim scope and interpretation of the claims only in infringement proceedings (which is a matter for national law). As such, it was found that a literal interpretation of the claims should be applied in proceedings before the EPO in accordance with Article 84 EPC. The Board in the present case disagreed. Instead, it found that the first step in infringement analysis is to determine the claim scope under a normal construction (then equivalents may be considered after the initial interpretation). It therefore concluded that Article 69 EPC was relevant to claim interpretation in EPO proceedings, and particularly to interpretation for the purposes of added matter under Articles123(2) and (3) EPC.
Decision
The question therefore became whether the description must be taken into account when determining the scope of the claimed subject matter under Article 69 EPC. The Board found that it should. However, it also stated that the description should not be considered to have the same weight as the claims. It is only the claims that determine the extent of protection and in the case of contradiction between the description and the claims, the ordinary meaning of the words in the claims should take precedence.
In the end, the interpretation came down to a comma (or the lack thereof). The Board found that claim 1 as granted – i.e., “a rotary joint body (200) of a plastic material, said body having a free inner bore holding a capacitive data link…” – must be interpretated such that it is the free inner bore that possesses the capacitive data link. This was “technically sensible and plausible” and it was not illogical that a bore may ‘hold’ a component. Thus, there was no technical reason for the skilled person to depart from this interpretation (for example, the description did not contain anything which makes it nonsensical). The Board went on to note that the mere mention in the description of an embodiment which comprises a capacitive data link in the rotary joint body, i.e., not in the free inner bore, is not a sufficient reason to instead interpret the claims such that it is the rotary joint body that holds the capacitive datalink. This interpretation of the claims is therefore in contrast with the disclosure of the application as filed, where it is only described that the rotary joint body holds the capacitive link, not the free inner bore.
Due to the discrepancy between the subject matter of the granted claims, as interpreted by the Board, and the information provided in the application as filed, the patent was revoked for added matter (Articles 123(2) and 100(a) EPC).
Request for correction (Rule 139 EPC)
The Patentee filed auxiliary requests for correction under Rule 139, which allows for the correction of linguistic errors, errors of transcription and mistakes if it immediately evident that nothing else would have been intended other than what is offered as the correction, in which the relevant clause in claim 1 was amended in one of two ways:
- “a rotary joint body of a plastic material, said body, having a free inner bore, holding a capacitive data link”; and
- “a rotary joint body of a plastic material, said body having a free inner bore, said body holding a capacitive data link”
In the first, the inclusion of commas removed the limitation that the free inner bore must hold the capacitive datalink. Instead, any part of the rotary joint body may hold the capacitive datalink. Therefore, as expected, this claim was found by the Board to unallowably extend the scope of protection and was rejected for adding matter under Article 123(3) EPC (which requires that “the European patent may not be amended in such a way as to extend the protection it confers”).
The Board also refused the second correction, i.e., where the Patentee attempted to make it clear that it was “said body” holding a capacitive data link.
The addition of the expression “having a free inner bore” in claim 1, i.e., the amendment that the request aimed to correct, was made by the Examining Division in the text intended for grant (sent with the communication under Rule 71(3) EPC). The Patentee approved the proposed text and the application proceeded to grant. However, Rule 139 EPC only allows for the correction of errors or mistakes “in any document filed with the European Patent Office”. The Patentee’s approval of the text intended for grant, including the amendment made by the Examining Division, was not considered a document filed with the European Patent Office. Therefore, the Board refused the correction for this reason alone, regardless of whether the other requirements for a correction were met.
Key Takeaways
This case serves as a reminder to pay close attention to the precise wording of claims and to ensure consistency with the invention described in the application. Even seemingly minor discrepancies, such as a missing comma, could have significant consequences for the interpretation of a claim.
There is also a consideration of the limitation of when, and how much, the description may be used to interpret the claims. In the present case, the Board held that Article 69 EPC can, and should, be relied on when determining the scope of the claimed subject-matter in proceedings before the EPO. However, it also noted that “one must not deduce that the description has the same weight as the claims”. In other words, it appears that this Decision confirms that, under Article 69(1), the description should be relied upon to interpret the claims but, also, that the weight given to the description depends on the clarity of the claims, e.g., the description has more weight if the claim is fundamentally unclear or if the description contains something which makes the claim interpretation nonsensical.
This case also highlights the importance of carefully checking amendments introduced by the EPO during grant proceedings, especially if the amendments concern the claims.
