Concern with the need for a standard of obviousness acceptable in all member states made itself felt early in the EPO's case law. One of the earliest Board of Appeals decisions stated that, "the inventive step (required by the EPO) should not be below what may be considered the average amongst the standards presently applied by the contracting states." Thus patentees would have a fair degree of certainty if their patents were litigated in a national court. [52]

5.1 The Problem and Solution Approach

The normal approach to questions of inventive step adopted by the EPO has become known as the "problem and solution" approach. This was articulated by an Appeal Board in the first reported decision on obviousness, the case of Carbonless Copying Paper, an official headnote to which reads as follows:

Assessment of the inventive step of a chemical invention...has to be preceded by a determination of the technical problem based on objective criteria. If the prior art cited shows that this problem has to be regarded as the selection of another novel agent from a known class...then it can generally also subsequently be argued that the problem consists in selecting a surprisingly improved agent. [53]

The decision made clear that perception of a problem may change as additional art is brought to light, but that by reformulating one's claims it may be possible to claim an inventive solution of some different problem in the course of the prosecution.[54]

The definitive adoption of the problem and solution approach followed shortly afterwards in Metal Refining/BASF, [55] when the Appeal Board stated:

When assessing inventive step it is not a question of the subjective achievement of the inventor. It is rather the objective achievement which has to be assessed. Objectivity in the assessment of inventive step is achieved by starting out from the objectively prevailing state of the art, in the light of which the problem is determined which the invention addresses and solves from an objective point of view and consideration is given to the question of the obviousness of the disclosed solution to this problem as seen by the man skilled in the art and having those capabilities which can be objectively expected of him. This also avoids the retrospective approach which inadmissibly makes use of knowledge of the invention, as feared by the appellant.

One fear expressed by opponents of the "problem and solution" approach to obviousness was that such an approach would fail to deal adequately with situations in which the invention lay in realizing the nature of the problem to be solved, or in which the art had over the years failed to appreciate a simple solution that, once pointed out, seemed obvious.

These fears have to some extent been mollified by decisions of the Appeal Boards in cases concerning such issues. The general approach to questions of obviousness is, first, to define the closest prior art, then to see what problem had to be solved to move from that point to the invention claimed, and finally to determine whether the solution to that problem was obvious in light of the general knowledge of one skilled in the art of the field of the invention, or other fields where the same or similar problems arise.[56] Nevertheless there is an increasing tendency for Examiners to try to force one to define the problem solved as being to provide an "improved" widget rather than simply an alternative one. Some support for this is found in Hot-gas Cooler/Sulzer.[57] In this case, the Appeal Board took the view that the broad problem postulated by the Appellant had already been solved so that the only problem left was to improve that solution.

5.2 Previously unrecognized problems

Although in Hearing Aid/Bosch, [58] it was held that there was nothing inventive in merely being the first to pose a problem if that posing was itself obvious, in Simethicone Tablet/Rider, [59] it was held that:

The discovery of a yet unrecognized problem may, in certain circumstances, give rise to patentable subject matter in spite of the fact that the claimed solution is retrospectively trivial and in itself obvious.

In this case, the Board stated that:

The question regarding inventive step...is not whether the skilled man could (have taken the step claimed), but whether he would have done so in the expectation of some improvement or advantage.

The Board did, however, caution that unexpected results themselves did not suffice to establish patentability if the step taken was itself obvious, and the unexpected results merely a "bonus."

In Expression in yeast/Gennentech[60] the question of whether something was "obvious to try" meant that it lacked inventive step was considered. The Board revoked a European Patent covering use of recombinant techniques in yeast which had previously been used to express genes in bacteria where one skilled in the art would not have expected serious difficulty or risk in applying the teaching in one field to the other. Thus the application of the technology developed in bacteria to yeast was obvious to try with a reasonable expectation of success.

The possibility that drafting a claim too broadly may expose a claim to an obviousness attack that would not otherwise succeed has, been recognized in the European Patent Office in, for example, Triazoles/Agrevo [61]. In this case, the examining division had held that a claim was so broad that it covered compounds for which it was not credible that they had the stated technical effect and that the specification was therefore insufficient in failing to describe how to obtain this effect. The Appeal Board found that this was not a valid ground for rejection as such but went on to hold that in a case where the question of inventivity was dependent on showing that compounds had a particular effect (in this case they were similar to prior art compounds so that the problem to be solved was selection of those compounds that had meritorious properties) then a claim that extended beyond those compounds that it was credible had the technical properties in question would cover obvious compounds and so be unpatentable because it lacked an inventive step.

5.3 "Simple" Inventions and Secondary

The fear that the problem and solution approach might lead to findings that simple solutions were all obvious was alleviated by the decision of Packing Machine/Michaelson. [62] This case involved the use of a well known element for a new purpose. The Board commented:

The yardstick for measuring the inventive step applied to such uses must...go beyond the mere appreciation of such different use. Therefore, the Board invited the appellant to put forward evidence why a specialist having knowledge of electrical heating equipment, who is the person skilled in the art to be called upon to solve the problem at hand, would not think of replacing the conventional...elements by (the claimed) elements in order to avoid the recognized shortcomings, even though he was aware of certain desirable characteristics of the claimed evidence and that no insurmountable difficulties would attend their use.

Under these circumstances, the Board felt that the invention claimed was prima facie obvious but that it was necessary "to consider whether there are any valid secondary considerations tending to displace [this prima facie assessment.]"

As secondary considerations, the applicant advanced the following:

In other decisions, the Boards have also cautioned against putting too much weight on commercial success unless it can unequivocally be tied to some technical effect rather than extraneous factors. [65]

5.4 Prejudice

The Appeal Boards have addressed the question of prejudice in a number of cases. For example, in Gelation/Exxon [66] it was emphasized that the applicant bears the burden of proving that a prejudice existed against the step he took to make the claimed invention. On the other hand, in seeking to establish prejudice one can combine documents (including contradictory documents) in a way that would be impermissible in seeking to establish obviousness. [67]