T 2377/18 - CPA and binding effect starting point

Key points

• This decision illustrates the substantive aspects of the choice of the starting point document for the problem-solution approach. 
• It is a basic feature of the PSA that one document (or embodiment) is taken as the starting point and that obviousness of the claimed invention is analysed in view of the distinguishing feature of the claimed invention in view of that document and in view of the objective technical problem solved by that feature. The objective technical problem can generally be formulated as "how to modify the starting point document so as to achieve the technical effect", the technical effect being the effect achieved by the distinguishing feature, in the context of the claimed invention, compared to the starting point document.
• In the present case, the patentee argues that D1 is not the CPA.
• The Board (al quotes in translation): " In this sense, the [patentee's] arguments against the selection of D1 as the closest prior art seem to imply that the problem and solution approach must be applied based on only a single prior art document or exemplary embodiment, namely from the one to be initially selected closest prior art. This is not consistent with established case law." 
• The Board: "If the person skilled in the art has several viable paths, i.e. paths starting from several different documents or exemplary embodiments that could lead to the invention, the boards of appeal have consistently held that the ratio of the problem-solution approach requires the invention to be examined in relation to all of these paths before inventive step is acknowledged. If the [claimed] invention is obvious to a person skilled in the art in at least one of these ways, it is not inventive. If the inventive step is denied, the choice of starting point does not have to be specifically justified" 
• This is indeed established case law and was already indicated by Szabo 1986.
• However, the choice of the starting point document is important, as far as substantive aspects are concerned. In the present case, the claim was directed to a hood furnace (also translated as a bell annealer), in any case a batch design; D1 was about a continuous furnace. 
• " The board agrees with the appellant that the basic structure of a conventional bell annealer plant is part of the specialist knowledge of a person skilled in the art. However, such bell annealer furnace systems are structurally fundamentally different from the continuous heat treatment system disclosed in D1. The expert faced with the above task would therefore have no reason to combine the different building constructions. Even if he wanted to combine them, he had no idea how the well-known bell annealer systems could be integrated into the continuous furnace at D1. To do this, he would have to completely redesign D1's heat treatment facility in an unknown way. 
• " In addition, according to the settled case law of the Boards of Appeal (supra, I.D.3.6), the selection of the closest prior art not only defines the subject matter serving as a starting point, but also defines the framework for further development, namely a further development within this genus. A change from the consciously chosen type to another, previously known but not selected other type during the further development (i.e. here from continuous furnaces as disclosed in D1 to bell annealers) can then only be regarded as the result of an ex post facto analysis." 
• 
  

EPO T 2377/18

The link to the decision is provided after the jump break.

https://www.epo.org/law-practice/case-law-appeals/recent/t182377du1.html