5.5.3 Unusual parameters

Where unfamiliar parameters have been used to define the solution to a technical problem, the patentee is under a particular obligation to disclose all the information necessary to reliably determine the new parameter, in accordance with T 172/99, T 815/07, and T 593/09 (as recapitulated in T 1845/14).

In T 172/99 the board found that in the case of claimed subject-matter relying on a newly formulated and hence unfamiliar parameter to define the solution of a technical problem by which a relevant effect is achieved, the patentee is under a particular obligation to disclose all the information necessary reliably to define the new parameter not only (i) in a formally correct and complete manner such that its values can be obtained by a person skilled in the art without undue burden, but also (ii) in a manner which reliably retains the validity of the parameter for the solution of the technical problem for the application or patent in suit as a whole in the sense that the values routinely obtained will not be such that the claimed subject-matter covers variants incapable of providing the relevant effect or, therefore, of solving the associated technical problem (followed in numerous decisions; see, for example, T 914/01, T 179/05, T 75/09 and T 1287/15 (dispute whether unfamiliar parameter (yes) – patentee's particular obligation identified in T 172/99 not met)).

The board in T 54/17 cited the settled case law that two requirements had to be met for the purposes of Art. 100(b) EPC: the skilled person had to be able, firstly, to derive from the patent specification at least one way of carrying out the claimed invention and, secondly, to carry out the invention over the whole range claimed. The board held that the (second) requirement was particularly important, especially where a claim contained unusual parameters (parameters "operational result" and "reaction pattern" – certain meaning in German – not readily understood here as having a technical meaning). The board referred to the conditions listed in T 172/99. The board concluded that the skilled person was unable to carry out the invention.

The board in T 602/10 found that the proprietor had deliberately decided to use a method for determining rugosity which was different from the one commonly used in the state of the art. It was therefore its duty to provide full information with regard to the means and the procedures for implementing said method. In general terms, when the issue of sufficiency concerned the description of a method for determining a parameter, the less common the method the more accurate the information provided in the description should be. In the case at issue, in the absence of any known prior-art work applying the same method used in the patent for measuring the rugosity, the skilled person had to rely primarily on the teaching of the patent to put the method into practice.

In T 131/03 the board observed that, once an opponent had established a strong presumption that unusual parameters used to define the claimed subject-matter were inherently disclosed in the prior art, the patent proprietor could not simply claim the benefit of the doubt. It was instead incumbent on it to establish to what extent the parameters it had chosen to use to define its invention actually distinguished the claimed subject-matter from the prior art.

The board in T 1287/15 decided that the "incremental adsorption capacity" parameter was a newly formulated and hence unfamiliar parameter. This case was similar to T 172/99, but was not comparable with T 231/01, in which the relevant parameters had been sufficiently described by reference to their measuring methods. In T 1287/15 the principal issue was the understanding of the notion and not so much the availability of a measuring method, but considerations in the catchword of T 172/99 were nevertheless relevant. The patent proprietor (appellant) was under a particular obligation to disclose all information necessary to reliably define the new parameter it had chosen to introduce although an established parameter was available. That particular obligation, identified in T 172/99, had not been met.

In T 1414/08 the board observed that sufficiency of disclosure might be questionable if specific values of an unusual parameter are formulated in a patent as essential to the invention but no method of measuring that parameter is either known in the art or disclosed in the patent. But in the case at hand the parameter (tensile strength) was not unusual. Depending on the method of measurement, there exists an uncertainty as to the actual end values of the range for the tensile strength mentioned in the independent claims (issue of Art. 84 EPC rather than of Art. 83 EPC).

In T 1553/16 the board held that the issue at stake was not related to an alleged ambiguity in the determination of a parameter, which in some cases could indeed be a matter of clarity, but rather to a lack of essential information needed to run a specific procedure (namely the APTF-2 procedure), which had not been shown to be usual in the art but was necessary to determine an unusual feature (F time) mentioned in the operative claims. In other words, the lack of information did not result in the claim being unduly broad or unclearly delimited, but derived from the presence of a parameter which was in itself very specific, but whose method of measurement had been kept secret.

See also T 1452/16 (unusual parameters – alleged prior use – public availability of a product): addressing the fact that it had been possible for the patent proprietor to obtain and test samples, the board found that, when samples manufactured after the priority date were tested, it was legitimate to ask whether the results obtained were representative of the ratios present in the prior-art samples. However, where a patent proprietor used a parameter not used in the prior art, it bore the burden of proving that the prior art did not fall within the terms of the claim.

Other decisions: T 1764/06 (no benefit of the doubt – see catchword); T 288/06 (unusual method of measuring parameter); T 815/07; T 1920/09 (unusual parameter and presumption); T 484/05; T 1995/15 (implicit feature – where an unusual parameter is used, onus is on the applicant to establish novelty over prior art if there no reason to doubt that the prior art implicitly meets the parameter); T 615/19 (decisions establishing insufficient disclosure owing to unclear or inadequate information on the method of determining an unusual parameter held inapplicable to case in hand because the skilled person would not have encountered any difficulty).

Cf. T 1900/17 (fabric conditioners – use of a calculated partition coefficient such as ClogP for selecting nonionics – thorough discussion of whether ClogP was an unusual parameter).