The patent claims must clearly define the subject-matter for which protection is sought under
Art. 84 EPC. In
T 94/82 (OJ 1984, 75) it was held that this requirement was fulfilled in a claim to a product when the characteristics of the product were specified by parameters relating to the physical structure of the product, provided that those parameters could be clearly and reliably determined by objective procedures which were usual in the art. In such a product claim, it sufficed to state the physical properties of the product in terms of parameters, since it was not mandatory to give instructions in the claim itself as to how the product was to be obtained. The description, however, had to fulfil the requirements of
Art. 83 EPC 1973 and thus enable the person skilled in the art to obtain the claimed product described in it (see also
T 487/89,
T 297/90,
T 541/97). Nor should this be understood as also referring to those variants falling under the literal wording of the claim but which the skilled person would immediately exclude as being clearly outside the scope of practical application of the claimed subject matter, for example, claims including an open ended range for a parameter where it was clear for a skilled person that the open-ended range was limited in practice. Values of the parameter not obtainable in practice would not be regarded by the skilled person as being covered by the claims and thus could not justify an objection of insufficiency of disclosure (
T 1018/05).