6.3.2 Legal basis for using description and drawings to interpret the claims

Several decisions applying the principle whereby the description and drawings are used to interpret the claims refer to Art. 69(1) EPC 1973 (T 23/86, OJ 1987, 316; T 16/87, OJ 1992, 212; T 238/88, OJ 1992, 709; T 476/89; T 544/89; T 565/89; T 952/90; T 717/98). Other case law emphasises that Art. 69 EPC 1973 (Art. 69 EPC) and its Protocol are primarily for use by the judicial organs which deal with infringement cases (see e.g. T 1208/97, T 1279/04, T 223/05, T 1047/11). The board in T 556/02 made it clear that it applied solely the general principle of law applied throughout the EPC that a document had to be interpreted as a whole (see e.g. T 23/86; T 860/93, OJ 1995, 47). Art. 69 EPC 1973 was a specific application of this general principle. See also T 1871/09, T 1817/14.

In T 1279/04 the board did not share the appellant's (patent proprietor's) view that, for the purposes of assessing novelty in opposition proceedings, claims should be interpreted in accordance with Art. 69(1) EPC 1973 and the Protocol on its interpretation. Art. 69(1) EPC 1973 and its Protocol related to the extent of protection conferred by the patent or patent application, which was primarily of concern in infringement proceedings. They served to determine a fair protection – inter alia by reference to the description and drawings – in circumstances where the claim wording was set in stone. By contrast, in examination and opposition proceedings the value of future legal certainty was paramount. In this forum the function of the claims was to define the matter for which protection was sought (Art. 84, first sentence, EPC 1973). There was no case for anything other than a strict definitional approach (for an interpretation of this approach, see T 1534/12), given that in this procedural stage the claim could and should be amended to ensure legally certain patentability, in particular novelty and inventive step over any known prior art. Amendment rather than protracted argument should be the answer to genuine difficulties of interpretation in all aspects of the examination and opposition procedure, it being acknowledged that amendments to a patent as granted should be occasioned by grounds for opposition. See also T 145/14.

Likewise in T 1808/06 the board emphasised that, when the description has to be amended with regard to the requirement of Art. 84 EPC, it was only in situations where the removal of inconsistencies was not possible for procedural reasons (e.g. no amendment possible of the granted version) that – purely as an auxiliary construction – Art. 69(1) EPC could be invoked for an interpretation of the claimed subject-matter.

In T 1646/12 the board stressed that Art. 69(1) EPC concerned only the extent of protection, which in turn was relevant only for the purposes of Art. 123(3) EPC and in national infringement proceedings. A general requirement that claims be interpreted with the help of the description could not be derived from Art. 69(1) EPC. It was nevertheless a general principle that a term could be interpreted only in context. Terms in a claim therefore had to be interpreted in the overall context of the claims set and the description (see also T 1817/14). Two extremes had to be avoided. On the one hand, limiting features mentioned in the description but not in the claims could not be read into the latter (see in this chapter II.A.6.3.4). They could not be inserted this way through interpretation, but only by amending the claims. On the other hand, claims could not be considered in complete isolation from the description. The skilled person interpreting the claim had to at least ascertain whether the expressions used were to be understood in their ordinary literal sense or whether they had a special meaning defined in the description. Likewise, if the claims were obscure, the skilled person had no alternative but to search for clarification both in the other claims and in the description and drawings (see in this chapter II.A.6.3.3). Using the description to interpret the claims was therefore admissible within certain limits, and sometimes even necessary; there was no need to invoke Art. 69(1) EPC.

In T 1473/19 the board disagreed with the findings in T 1279/04 and held that Art. 69 EPC in conjunction with Art. 1 of its Protocol can and should be relied on when interpreting claims and determining the claimed subject-matter in proceedings before the EPO, including for the purpose of assessing compliance with Art. 123(2) EPC. According to the board, interpreting the claimed features for the purposes of establishing the (first part of a) patent claim's extent of protection was not different from interpreting and determining the claimed subject-matter for the purposes of assessing compliance with Art. 54, 56, 83 and 123(2) EPC. Moreover, the general application of Art. 69 EPC and its Protocol in proceedings before the EPO was also required to ensure uniform and consistent claim interpretation, if for example the relevant feature needed to be interpreted not only under Art. 123(3) EPC but – as in the underlying case – also under Art. 123(2) EPC. The board pointed out that national courts applied the rules for the interpretation of claims in Art. 69 EPC and the Protocol in both infringement and revocation proceedings. In addition, the board agreed with the view in decisions T 2007/19, T 1646/12 and T 556/02 that it was a general principle that a term could be interpreted only in context, so that terms in a claim had to be interpreted in the overall context of the claims set and the description. Nevertheless, in T 1473/19 the board also stressed that the primacy of the claims according to Art. 69(1), first sentence, EPC limits the extent to which the meaning of a certain claim feature may be affected by the description and the drawings. Decision T 1473/19 was fully endorsed in T 450/20, T 1494/21 and T 367/20. The latter included several decisions of national courts in the contracting states as examples of national case law on claim interpretation according to Art. 69 EPC in respect of revocation proceedings.

In T 169/20 the board disagreed with the findings in T 1473/19 that Art. 69(1) EPC, in conjunction with Art. 1 of the Protocol, applies to the interpretation of the claims for the purpose of assessing patentability. The board held that the provisions in Art. 84 EPC and R. 42 and 43 EPC provided an adequate legal basis for claim interpretation when assessing the patentability of an invention. In particular, the requirement that the claims shall be "supported by the description" in Art. 84, second sentence, EPC provided a direct and unambiguous indication of the description's function as an aid for understanding the subject-matter of the claims.

See also in this chapter II.A.6.3.4 "Reading additional features and limitations into the claims".