Enlarged Board decision G 2/88 (OJ 1990, 93) related to a change of claim category in opposition proceedings, and in particular to the change from a product claim to a claim directed to the use of the product for a particular purpose, which the Enlarged Board allowed. The protection conferred by a patent was determined by the terms of the claims (Art. 69(1) EPC 1973), and in particular by the categories of such claims and their technical features. An amendment of granted claims directed to "a compound" and to "a composition including such compound", so that the amended claims were directed to "the use of that compound in a composition" for a particular purpose, was not open to objection under Art. 123(3) EPC 1973. For it was generally accepted as a principle underlying the EPC that a patent which claimed a physical entity per se, conferred absolute protection upon such physical entity, for all uses of such physical entity, whether known or unknown. It followed that if it could be shown that such physical entity (e.g. a compound) was already part of the state of the art, then a claim to the physical entity per se lacked novelty. It also followed that a claim to a particular use of a compound was in effect a claim to the physical entity (the compound) only when it was being used in the course of the particular physical activity (the use), this being an additional technical feature of the claim. Such a claim therefore conferred less protection than a claim to the physical entity per se.
However, the Enlarged Board distinguished between use claims, which define the use of a particular physical entity to achieve an "effect", and claims which define such a use to produce a "product". The latter type of claim was a process claim within the meaning of Art. 64(2) EPC 1973.
(i) the use of a physical entity to achieve an effect, and
(ii) the use of a physical entity to produce a product.
A use claim of the latter category (ii) is to be considered as a process claim comprising physical steps for producing the product using the physical entity with the consequence that this type of use claim is a process claim within the meaning of Art. 64(2) EPC 1973. Pursuant to that article, the product insofar as it is directly obtained by that process, is also protected. Hence, the product, when obtained by that process, is within the scope of protection conferred by that type of use claim. Consequently, the use claim as amended conferred protection to the claimed use and to the product directly obtained by the claimed process, which, in the case at issue, extended the protection conferred (for a case where the issue of Art. 64(2) EPC 1973 was not considered, see however T 879/91).
The board in T 75/90 allowed a switch from a claim for a "transport box ... adapted for the method according to one of the claims 1 to 3" to one for the "use of transport box adapted for the method".