Source: http://k-slaw.blogspot.com/2010/04/t-128106-cack-handed-lexicography.html
Timestamp: 2019-07-22 09:40:04
Document Index: 37049864

Matched Legal Cases: ['Art. 123', 'Art. 84', 'Art. 69', 'Art. 84', 'Art. 69', 'Art. 69']

K’s Law: T 1281/06 – Cack-handed Lexicography
As often, it's kind of you, Oliver, to derive practical tips therefrom.
It seems that for the purpose of clarity, the patent description can be its own dictionary only if it would not be a problem anyway to introduce the definition into the claim (in the sense of Art. 123(2) EPC). So the practical benefit of this exception seems very limited.
Trying to find the origin of this exception, I have so far found T 311/93, which indeed states that a specification can be its own dictionary. However, that was in the context of interpreting the priority document, NOT for the purpose of clarity. I think it's quite normal to use the description for interpreting the claims, e.g. to show that a claim term does cover a feature disclosed in a prior art document or for the purpose of infringement, but the point of Art. 84 is that the claims should be clear on their own, i.e. without the description (T 0988/02, pt. 3.3.1).
Clearly there is case law applying "a specification can be its own dictionary" to clarity, but there is also case law applying Art. 69 EPC to clarity. I thought the latter approach is now rejected by most Boards. I wonder what most Boards think of the former.
T 1321/04 (mentioned in the Case Law book) does not refer to Art. 84. T 523/00 (referred to by T 1321/04) does state that the specification can be its own dictionary in the context of clarity, but derives this from Art. 69, and unless I'm very mistaken most Boards do not agree that Art. 69 is to be used when examining clarity.
So far I'm not convinced that there is much case law to be found in support of this principle that claim terms may be defined in the description.