5.2. Distinguishing features
In T 1764/06 the board noted that the only expressed distinction between the definition of the claimed photocatalyst and the photocatalyst of D1 relied on a parameter feature that was not usual, let alone common, for the skilled person. The onus of proof in that respect lay on the applicants, but no proven distinction had been shown. As regards the benefit of the doubt, which in the applicant's view was to be accorded to applicants in complex situations without direct disclosure, the position of the board was that in a situation where the applicants have used an unusual parameter feature to define their product, which unusual parameter feature represents the only distinction over otherwise identical known products, and the applicants have decided not to provide evidence that the parameter feature as such represents a difference in the claimed products from the known products, no benefit of the doubt could be accorded (see also T 1764/06, T 1995/15). The same applies in inter partes proceedings (T 131/03, T 740/01, T 1666/16).
See also chapter III.G.5.2.2 "Cases in which the burden of proof was reversed".