4.2. Concept of "in due time"
4.2.3 Fair response – examples
In T 1551/14, during the written proceedings that followed initial oral proceedings before the opposition division, at which witnesses had been heard, the patent proprietor had filed a new auxiliary request limiting the subject-matter of the independent claims by a new feature. Having been summoned to a second round of oral proceedings, the opponent had filed, within the period fixed under R. 116 EPC, a statutory declaration made by one of the previously heard witnesses and proposed that the witness be heard again. For the board, this declaration, which dealt with matters that had become relevant only once the new auxiliary request had been filed, was a direct and timely reaction of the opponent (appellant) to that request, and therefore could not be treated as filed late. The board did not share the appellant-proprietor's misgivings that the declaration conflicted with the case made so far. That submissions filed as a legitimate reaction to an amendment to the counter-party's case contained contradictions was in any event not a proper basis for refusing to admit those submissions from the outset.
In T 2734/16 the board held that a new line of attack on inventive step pursued in response to and using the documents submitted by the patent proprietor with its reply to the opposition should not be considered late-filed per se. For reasons of "equality of arms", the new attack could be admitted into the opposition proceedings even if the documents ultimately proved no more relevant than other documents.
In T 1711/16 the opponent had filed further evidence within the final date set in accordance with R. 116(1) EPC in order to overcome concerns expressed by the opposition division for the first time in its communication sent out in preparation for the oral proceedings. The board pointed out that the prima facie relevance of these documents, which in the proprietor's opinion was lacking, was irrelevant to the issue of admittance. The decisive point was whether these documents and the submissions made in respect of them dealt with the concerns of the opposition division and were timely submitted, i.e. whether they represented a fair answer to the concerns raised by the opposition division. Accordingly, the board overturned the opposition division's discretionary decision not to admit the evidence at issue.
- T 0733/23
In T 733/23 the opposition division had concluded that there had been insufficient evidence to prove that the data sheets D2, D4, and D7 to D9 had been made available to the public before the filing date. Rather than concluding that, as a result of the data sheets not being considered state of the art under Art. 54 EPC, the subject-matter of the claims was novel, the opposition division decided not to admit them into the opposition proceedings. The board concluded that not admitting these data sheets, filed in due time, constituted a substantial procedural violation (see details as from point 4 of the Reasons including discussion on D19, an affidavit).
The board, in support of its decision, presented some key considerations on public availability of advertising brochures and data sheets, as well as the standard of proof to be applied. The board stated that when a document was clearly intended to be publicly distributed, as was the case with advertising or commercial brochures, the absence of a specific publication or distribution date, a situation quite common in this type of document, was not in itself sufficient to conclude that the document did not constitute prior art. As with any other type of evidence, the key question was not whether the exact date of publication could be determined, but whether it could be established that the relevant subject-matter was made available to the public before the priority or filing date.
Data sheets often represent an intermediate case between internal documents and advertising brochures. Where no publication date is present, the board held it should first be assessed whether the document was intended for public distribution. If so, additional sources must be examined to establish whether the relevant subject-matter was publicly accessible before the patent’s filing or priority date. Here, the opposition division had failed to provide a reasoned decision on public availability, giving no weight to the dates printed on their front pages.
As to the standard of proof, the present board concurred with the position in T 1138/20 that there is only one standard of proof: the deciding body must be convinced, based on the underlying circumstances.
According to the present board, this did not imply that all cases were to be treated identically, as in practice the degree of proof required to establish credibility (i.e. to persuade the board) might vary depending on the specific circumstances. In other words, it was not the standard of proof that adjusted with the circumstances, but rather the credibility of the arguments made by the different parties. For example, when the evidence was exclusively controlled by one party, any gaps in the relevant information might significantly undermine that party's credibility. Conversely, when the information was equally accessible to both parties but only one party submitted evidence, merely raising doubts might not be sufficient to challenge the credibility.
In the present case, the conclusions of the opposition division suggested that the standard of proof "up-to-the-hilt" was applied to determine the public availability of the data sheets. Even if the board agreed that different standards should be applied, this would not be justified in the case in hand, as the relevant information to prove the public availability of the data sheets was not within the exclusive sphere of the appellant (opponent). In this instance, the relevant information would more likely be within the sphere of the patentee. Therefore, there was no basis for applying the strict standard of "up-to-the-hilt" or for questioning the credibility of the appellant (opponent) solely on the grounds that some information was missing.
The patentee argued that, when in doubt, the patent should be upheld. The board disagreed. Fact-finding boiled down to a binary exercise: either something had been proven, or it had not. In addition, there was no presumption of patent validity in proceedings meant to re-assess the validity of this very patent.