3.7. Unspecified features

In T 88/87 the disputed feature was an applicator member which was capable of springing back to its original shape upon release of the pressure applying it against the surface to be coated. The spring back capability depended on several parameters such as, for example, the strength and resiliency of the material of the cap and the thickness of the central portion of the cap. The board found that to avoid an undue limitation of the scope of the claim a functional characterisation relying on the resulting effect was allowable. The extent to which the applicator member should be capable of springing back could be specified by the indication of the effect to be produced (i.e. the freeing of the orifice) because the person skilled in the art could verify the result directly by tests involving nothing more than trial and error.

The objection in T 487/89 (raised in relation to sufficiency of disclosure) was based on the fact that the claim had indicated both tenacity and toughness with a lower but no upper limit. The opposition division took the view that such "open-ended" parameters were always objectionable if they related to an inherently desirable characteristic. The board, however, held that whether the absence of an upper or lower limit was acceptable in a claim in any individual case depended on all the surrounding circumstances. Where, as in the case in question, the claim sought to embrace values as high as could be attained above a specified minimum level, given the other parameters of the claim, then such open-ended parameters could not normally be objected to. This decision was confirmed by T 129/88 (OJ 1993, 598) for the question of clarity, T 297/90 and T 1018/05 for the question of sufficient disclosure (see also T 989/95, in which T 487/89 was agreed with but not applied). In T 586/97, on the other hand, the board found that the absence from any independent claim of any upper limit on the amount of a particular detrimental but necessary component in the chemical composition claimed was at variance with the aim of the invention as set out in the description, namely, to decrease the percentage of the undesirable ingredient in the claimed composition. An essential feature was missing, so that the claim was so broad it went beyond the scope of the invention as disclosed in the description. Therefore, the requirement of Art. 84, second sentence, EPC 1973 that the claims must be supported by the description was not met.

In T 227/91 (OJ 1994, 491) the claims comprised a coating thickness defined by a formula with two parameters (a) and (t). Parameter (a) represented the thermal diffusivity of the coating means and was therefore a feature inherent in the instrument. Parameter (t) represented the effective pulse time of the laser and was related to the laser operating conditions, not to the structure of either the laser or the instrument. The thickness defined in the claims was still connected with the mode of operation of the laser, that is, with a human factor irrelevant to the instrument per se. The extent of the protection conferred by the subject-matter of the claims was therefore regarded by the board as ambiguous and indefinite.

In T 455/92 independent claim 2 was worded as follows: "Covering [...] for a pressing [...], characterised by: (a) a length which corresponds at least to the circumference of the shell face of the pressing to be covered, (b) an overall breadth sufficient to cover the shell face and both end faces of the pressing, and (c) a fold such that [...] the breadth [...] corresponds to the breadth of the shell face of the pressing [...]". The board did not see this as a breach of Art. 84 EPC 1973, since reference had been made to a physical entity which was known; hence the range of sizes was definable in so far as it excluded packaging materials for other physical entities. Furthermore, it was self-evident to a skilled person in this field that the size of the packaging material (the covering) was dependent on the physical entity to be packed. In T 1020/13, however, the definition of a claimed entity by reference to a second entity that was not part of the claim was deemed a breach of Art. 84 EPC.