1.11.8 Insertion of an ambiguous feature in the claim

In T 792/94 the board ruled that since the teaching of claim 1 as amended was ambiguous (Art. 84 EPC 1973), allowing scope for an interpretation which extended beyond the overall teaching of the initial application, the amendment contravened Art. 123(2) EPC 1973.

In T 1067/02 the board came to the conclusion that the unclear nature of the amendment introduced upon grant in claim 1 as filed, i.e. the introduction of the term "complete", allowed two different interpretations and, although they were both technically sensible, neither of them was directly and unambiguously derivable from the general disclosure of the application as filed. Consequently, claim 1 of the main request extended beyond the overall teaching of the application as originally filed.

In T 2298/09 the board held that, although the alternatives g2 and g3 remained without a clearly derivable meaning, it was not disputed that their introduction into claim 1 added information to the teaching of this claim. The group of features (g) encompassing these alternatives could not be ignored when examining these amendments under Art. 123(2) EPC.

See also the related topic "Claim interpretation when assessing compliance with Art. 123(2) EPC" in chapter II.E.1.3.9 above.