8.2.2 Majority case law
In T 45/21 the appellant (opponent) alleged that the invention was insufficiently disclosed because the patent did not teach the temperature at which the pH was to be determined. The board stated that the assertion that the skilled person was unable to determine whether they were working within the claimed scope as such was not a valid basis for denying sufficiency of disclosure. The mere fact that a degree of variability existed in a claimed parameter could not as such lead to a finding of insufficiency of disclosure, if the influence of this variability on the possibility for the skilled person to carry out the claimed invention was not established. The board agreed with the appellant that the patent proprietor must not benefit from any lack of clarity in the patent. This was however not to say that such a lack of clarity must, on its own, necessarily lead to the rejection of the claim request or revocation of the patent for lack of sufficient disclosure. As explained in G 3/14 (see point 55 of the Reasons), a granted claim may turn out not to comply with Art. 84 EPC but such non-compliance must be lived with. To the extent that the alleged pH variation by up to 0.2 units led to a lack of clarity, the appellant did not show the effect of this lack of clarity on the assessment of sufficiency of disclosure.