Anticipation of parametric claims

3.54 Patent claims generally define the invention in terms of specific features or function. Specific parameters, such as directly measurable physical properties (e.g. the melting point of a substance, the flexural strength of a steel, the resistance of an electrical conductor) or mathematical combinations of several variables in the form of formulae, are generally included to distinguish the invention from the prior art.

3.55 The key consideration for such claims with respect to novelty is whether the claim may be distinguished from prior art that prima facie possesses all the features of the invention, but does not specifically disclose the defined parameter; or prior art that prima facie possesses all the features of the invention but discloses a different parameter. For example, if the known and the claimed products are identical in all other respects (which is to be expected if, for example, the starting products and the manufacturing processes are identical), then in the first place an objection of lack of novelty would be appropriate. The burden of proof that the defined parameter is a distinguishing feature vis-à-vis the prior art is shifted to the applicant. If the applicant fails to provide convincing evidence proving otherwise, no benefit of doubt can be accorded (see for example decision T 1764/06). If, on the other hand, the applicant is able to show, e.g. by appropriate comparison tests, that differences do exist with respect to the defined parameter, it may be further considered whether the application under examination discloses all the features (e.g. process steps) essential to manufacture the claimed product having the parameters specified in the claims, or the novelty objection may otherwise be withdrawn.