Zusammenfassung von Article 056 EPC für die Entscheidung T0746/22 vom 06.02.2025

In T 746/22 both the opponent and the patentee had appealed against the interlocutory decision of the opposition division maintaining the European patent in amended form. Regarding independent claim 15 of the main request, both parties agreed with the board's finding that feature F2 was the only distinguishing feature in view of the objective lens described in table 1 of D4 (closest prior art). F2 defined a mathematical relation between the focal length of a "first rear positive lens" (f3) and the total focal length (f) of the five lenses of the claimed objective lens system. The board was unable to see any effect of feature F2 other than to arbitrarily define a mathematical relationship between the focal length f3 of one of the lenses of the objective lens system with respect to the total focal length f of the objective lens system. However, in the present case, where the optical parameters of the claimed objective lens system were only very incompletely defined, the selection of a maximum value of f3 when f was fixed, or the selection of a minimum value of f when f3 was fixed, did not provide a technical effect relevant to the claimed invention. In view of the absence of any relevant technical effect related to the feature F2, the board found that no objective technical problem solved by feature F2 could be defined, and as was explained in T 176/97 , if the distinguishing feature of a claim has no effect of technical relevance on the claimed subject-matter and does not credibly solve an objective technical problem, then no inventive step can be based on it. In the present case, the objective lens system of claim 15 was considered to be no more than an arbitrary modification of the objective lens system of D4, which did not involve an inventive step within the meaning of Art. 56 EPC. The patentee argued that starting from the precise lens design in Table 1 of document D4, a skilled person would have a “perfect” lens design and thus no reason to modify any parameters without using hindsight from the invention. However, the board found this argumentation unconvincing because it assumed that, starting from the objective lens system disclosed in table 1 of D4, the skilled person would need a concrete incentive to modify it in a certain direction. This overlooked the point that the difference between the lens systems of claim 15 and of D4 was only an arbitrary modification of the lens design of D4. The question of whether there was a motivation to change the lens design of D4 did not arise in the present case. An arbitrary change to the lens design resulting in no relevant technical effect was in itself devoid of any inventive step. Claim 1 of the first auxiliary request also lacked an inventive step in view of D1 in combination with D4. The patentee had argued that D1 already disclosed a perfectly optimised lens system and that the objective lens system of D4 was no better than that of D1. Again, the board was unable to follow the patentee’s argument that only with hindsight would the skilled person consider replacing the lens of D1 with the lens of D4. D1 merely disclosed a general lens without further details of its optical characteristics. Thus, it was not hindsight, but simply the fact that the teaching of D1 was put into practice that leads the skilled person to search for a specific lens design and eventually find the objective lens system of D4. As with claim 15, the feature at issue in claim 1 provided no technical effect other than arbitrarily modifying the lens design of D4. Therefore, this distinguishing feature did not contribute to inventive step. The subject-matter of claim 1 of the second and the third auxiliary requests lacked an inventive step in view of D1 in combination with D4 for the same reasons.