T 0270/90 - Public prior use / Ballance of propabilities - #49

Citation rank: 49
No. of citations: 94

T 270/90 is a further decision within the 100 most-cited EPO Board of Appeals decsions, which deals with the required level of proof in public prior use cases.

The instant case T 270/90 is earlier than T 472/92 (which was recently commentated in this blog here) and the latter makes reference to the present case. The underlying cases, however, are slightly different, and therefore the later T 472/92 comes to a different conclusion regarding the required level of proof. The two decisions, however, do not contradict each other.

In the present case T 270/90 the appellant/proprietor argued strongly that, as a matter of law, the issue of public prior use needed to be proved more strictly than any of the other grounds of objection available under Article 100 EPC.

The Board disagreed. Regarding the principles of law that apply to appeal proceedings under the EPC, the Board stated:

"When arriving at their decisions, the Boards, in addition to exercising their inquisitorial powers (should this be necessary), decide the issues before them on the basis of the evidence adduced by the parties. Their decision need not, and indeed in most cases could not, be based on absolute conviction, but has, instead, to be arrived at on the basis of the overall balance of probability, in other words, on the footing that one set of facts is more likely to be true than the other (see decision T 182/89 of 14 December 1989, Extent of opposition/SUMITOMO, OJ EPO 1991, 391).

These principles clearly apply to all facts and matters alleged in relation to all grounds of opposition, including public prior use. Accordingly, the appellant's submission that the evidential test or burden of proof for prior public use needs to be stricter than that for other grounds of objection under the EPC is rejected." (point 2.1 of the reasons)

In the case at hand, the decisive question was whether certain products - which were delivered from the patent proprietor to the opponent before the date of filing of the patent in dispute - were delivered under a (tacit) confidentiality agreement or whether the delivery was under the terms of "general commercial use". This question was answered by the Board using the general ballance-of-propability standard, i.e., the Board simply considered, which set of facts presented by the parties was more likely to be true.

The Board decided that it was indeed more likely that the delivered products were already freely available on the market, and therefore the public-prior-use attack succeeded.

Comment: The above situation, i.e., a situation in which both parties have more or less the same access to the relevant evidence regarding an alleged public prior use, is rather unusual. Normally, the party alleging the prior use has power over most or all relevant evidence, whereas the proprietor is left to point to gaps or inconsistencies in the argumentation of the opponent. Under such (normal) circumstances T 472/92 decided that the more strict standard "up to the hilt" must be applied. See: here.

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Headnote:

In opposition proceedings decisions of the Boards on the evidence adduced by the parties must be arrived at on the basis of the overall balance of probability, as distinct from "beyond all reasonable doubt" or "absolute conviction". Each of the parties must therefore seek to prove facts alleged by it to that degree of proof.

The full text of the decision can be found here.