4.5. Alternative solution to a known problem

Article 56 EPC does not require that the problem to be solved should be novel in itself. The fact that the underlying problem of the patent have already been solved by the prior art does not necessarily require redefinition of the problem for the assessment of inventive step, if the subject-matter of the patent represents an alternative solution to this problem. (T 92/92, with reference to T 495/91; see also T 1074/93, T 780/94, T 323/03, T 78/05, T 2039/18).

For an inventive step to be present, it is not necessary to show improvement – substantial or gradual – over the prior art (T 100/90, T 588/93, T 620/99 T 1791/08). An earlier solution to a given technical problem does not preclude later attempts to solve the same problem in another, non-obvious way (T 588/93, see also T 615/05).

In T 2081/15 the non-obvious alternative solution was "technically plausible" and involved an inventive step, albeit a small one, over D1 and the skilled person's common general knowledge. On the other hand, in T 1179/16 the board noted that if the only contribution of the invention was to propose something different from the prior art (i.e. the provision of an alternative), then it was usually appropriate to consider that the skilled reader would take into account any alternative known in the underlying technical field (unless the closest prior art teaches away from it). The board stated that in such cases it might not be required to justify the selection of a particular solution, because it was assumed that an invention based on incorporating known features for the sole purpose of establishing novelty must be rendered obvious by a corresponding step of selecting any alternative known in the art. See also T 471/21.

In T 144/16 the board found the technical problem needed to be reformulated in a less ambitious way, and in view of the teaching of document (1), as the provision of alternative adhesive compositions. It noted that when looking for alternative compositions, the skilled person does not restrict the teaching of document (1) to its preferred embodiments, but takes into consideration all features taught in that document. In T 148/10 the board stated that the skilled person required no inventive skill to make a selection from known alternatives. The skilled person was able to consider advantages and disadvantages of their selection and would weigh them against each other.

In T 652/20 the board stated that there was no general requirement that all initially claimed compositions had to achieve a non-claimed technical effect to exactly the same level. Some of the initially described compositions might achieve this technical effect to a greater extent than others.

In T 1518/20 the board held that for providing an alternative method, no particular pointer from the prior art was needed to combine the teaching of secondary sources of information with that of the closest prior art. In such a scenario, in the absence of any counter-indicators that would provide teaching leading away from applying the relevant disclosure in order to modify the solution proposed in the closest prior art, a skilled person would apply such teaching rather than being conceptually and notionally confined to the disclosure of the provided examples.

In T 2004/21 the board noted that although the chewing gum of D2 had "inherent" mouthwatering properties, D2 disclosed neither these properties nor the problem of providing a mouthwatering effect in a user. "Mouthwatering" was not mentioned in any of the cited prior art documents. The claimed chewing gum which provided a "hydration or mouthwatering sensation" could therefore not be considered an alternative solution to a known problem.