Combination of three documents of different complexity in the assessment of inventive step.

In T 412/23 the Board of Appeal (The Board) concluded that assessment of inventive step based on three prior art documents is to be performed in successive steps of considering the combinations of documents. In a first step, the teaching of the closest prior art is combined with one of the other documents. In the next step, it should be considered whether the skilled person would consider combining the result of this combination with the third document. Herein, the context of the initial situation as well as the complexity and specific technical context of each document must be taken into account.

Background

European patent No. 09753877.1 was opposed in its entirety on the grounds of lack of technical character, lack of inventive step and lack of sufficiency of disclosure; Art. 100(a) EPC, Art. 52(2)(c) EPC, Art. 52(1) EPC, Art. 56 EPC, Art. 100(b) EPC, Art 83 EPC.

The Opposition Division (OD) rejected the opposition. The OD found that the subject matter of claim 1 as granted was new and involved an inventive step.

The Appeal

Oral proceedings were held before the Board. The appellant (opponent) (A) requested that the decision under appeal be set aside and the patent be revoked in its entirety. The respondent (patent proprietor) (P) requested that the appeal be dismissed.

Regarding inventive step, A argued that the skilled person would combine the teachings of the prior art (documents E0, E00, E15) discussed in paragraphs [0002], [0005] and [0007] of the patent, and thereby arrive at the subject matter of claim 1.

P argued that the skilled person wound not combine the teaching of the prior art discussed in those paragraphs, and would not arrive at the claimed subject matter without the use of inventive skills.

Both parties agreed that E0 represented the closest prior art.

The Board found that E0 fails to disclose two features – (a) and (b) - of granted claim 1.

A argued that two independent partial problems resulted from features (a) and (b). P argued that features (a) and (b) had a synergistic effect and that therefore the objective technical problem could not be broken into partial problems. The Board agreed with P that the features are functionally related and that formulation of partial problems was therefore not appropriate.

A argued that E15 disclosed feature (b) and E00 feature (a), that the skilled person would combine the teaching of E0, E00 and E15 and that the subject matter of claim 1 therefore lacked inventive step under Art. 56 EPC. A argued that E15 disclosed feature (b) in a very general context, independent of the specific and complex embodiments of E15, and that E00 discussed feature (a) in the same broad context as E0. Therefore the skilled person would combine the teaching of the three documents, in particular since all three documents were discussed in close relation to each other in the opposed patent and reflected general common knowledge of the skilled person.

P argued that the skilled person would not combine the teachings of E0, E00 and E15, which were discussed in the patent, because doing so would be contrary to the problem solved.

The Board did not agree with A’s reasoning, but essentially agreed with the OD and with P. The Board found that when solving a single objective technical problem the skilled person cannot combine in the present context the teachings of three documents in one go. The skilled person should first combine the teaching of E0 with the teaching of one of the documents E15 and E00, and then, in a second step, combine the result of this combination with the teaching of the other one of the documents E15 and E00.

The Board explained that, in the present situation, when the teachings of three documents are combined, this has to be done step by step. In a first step, the teaching of another document is combined on the basis of the teaching or embodiment of the closest state of the art. In a second step, it must then be examined whether the skilled person would also combine the result of this combination with the teaching of the third document. In doing so, the context of the initial situation as well as the complexity and specific technical context of each document or embodiment has to be taken into account.

The Board found the contexts and complexities of documents E0, E00 and E15 to be at very different levels, as was also clear from the contested patent. E15 related to examination through a complex method using complex image processing software, while E0 and E00 related to examination only with the human eye. E00 and E0 were however also of different complexity. E00 related to a basic method, involving only examination of a single visual property from one single angle, whereas E0 related to a different, more sophisticated method.

The Board concluded that the skilled person would not arrive at the claimed subject matter through combination of E0, E00 and E15 without the use of inventive step. Reasons were lack of pointers in the documents and differences in complexity of the respective prior art. At most, the skilled person might combine the teaching of E0 with the teaching of either E00 or E15. However, in the next step, the skilled person would not consider combining with the teaching of the third document, due to the differences in complexity of the documents. The skilled person would not in a first step turn to a simpler or more complex teaching than the closest prior art, to in the next step turn to a more complex or overly simplified teaching.

Decision of the Board (of Appeal)

The Board concluded that the grounds for opposition raised under Art. 100(a), (b) EPC do not prejudice the maintenance of the patent as granted. The opposition was therefore dismissed.

Summary written by the NLO EPO Case Law Team.