1.12.3 Amendment based on erroneous figure in the disclosure

In T 740/91 the board allowed a change in the upper limit of a range from 5 % to 0.6 %. The value of 0.6 % was explicitly disclosed in example IV. However, the patentee conceded that this figure had been inserted in error in place of the true figure of 0.49 %. The board concluded that the fact that the figure was wrong did not alter the fact that it was actually and credibly disclosed. It could thus be relied on as the basis for the new upper limit. This interpretation of Art. 123(2) EPC 1973 was consistent with its underlying intention, which was to protect the public from being faced at a later stage with claims which were wider in their scope than what had been disclosed in the application as filed, and published for the information of the public, including the applicant's competitors. In this case, any such competitor who had read the application as first published had formed the view that the originally claimed range of 0.1 to 5 % was too wide in the light of the prior art, and had thought that the broad claim could not validly be sustained. He would have seen at once that the highest figure for the cured epoxy resin given in any example was 0.6 %, as clearly disclosed in example IV, and therefore could not have been taken by surprise if the upper limit of 5 % were later to be reduced to 0.6 %.