T 1693/07 – No Problemo

[8.1] Since D14 does not even address the same problem as the patent in suit, the skilled person seeking to provide a process for the production of a polyamide prepolymer would have no reason even to consult D14. Thus this document cannot provide a valid closest state of the art according to the problem-solution approach, the existence of superficial similarities between the method disclosed in D14 and that specified in the operative claims 1-17 not withstanding (cf. T 506/95 [4.1, second section] and the decisions discussed therein).

From time to time the Boards make such statements. Please feel free to disagree, but I can’t help finding this reasoning faulty. If this statement were true in all its generality, prior uses – which do not disclose any particular problem solved at all - could never be the closest prior art. This cannot be true.

What is the closest prior art? How is it to be determined?

I have had a look at the Case Law Book (after all, the problem-solution approach is a case law creature) and the Guidelines (in order to see what the EPO expects Examiners to do). 

Section I.D.3.1 of the Case Law Book deals with the determination of the closest prior art in general:

“… The boards have repeatedly pointed out that the closest prior art for assessing inventive step is normally a prior art document disclosing subject-matter conceived for the same purpose or aiming at the same objective as the claimed invention and having the most relevant technical features in common, i.e. requiring the minimum of structural modifications (T 606/89, T 686/91, T 834/91, T 482/92, T 298/93, T 380/93, T 59/96, T 730/96, T 650/01). A further criterion for the selection of the most promising starting point is the similarity of technical problem (see T 495/91, T 570/91, T 439/92, T 989/93, T 1203/97, T 263/99). …” (my emphasis)

I find the first approach mentioned in I.D.3.1 perfectly reasonable. You first consider the prior art documents disclosing subject-matter conceived for the same purpose or aiming at the same objective as the invention. The condition of same purpose will in particular limit the search to a given technical domain. Among the documents that fulfil this condition, you then look for those that are structurally closest. The closest prior art should be among them.

The second approach (similarity of technical problem) is much more problematic (in every meaning of the word), in particular when considering the further steps of the problem-solution method where the objective technical problem is derived from the differences of the claimed subject-matter with respect to the closest prior art. Consequently, the objective technical problem is undefined as long as the closest prior art is not determined. So what problem should be considered? The subjective problem mentioned by the inventor? I do not think that this is reasonable, be it only because this would allow patent drafters to have an influence on the outcome of the inventive step assessment, by providing exotic problems to be solved. We need objective criteria. 

Curiously, the Guidelines for search appear to privilege the similarity-of-technical-problem approach. B-IV 2.5 provides the following instructions to the search divisions:

“… It may happen that the examiner does not find any documents published before the earliest priority date which prejudice the novelty or the inventive step of the claimed invention. In such cases, the examiner should, whenever possible, cite in the search report at least that prior art found in the course of search which discloses a solution to the same problem as that underlying the claimed invention (wherein this problem may change depending on the prior art retrieved (C-IV, 11.5.2) and wherein the known solution is technically the closest to the claimed solution (“closest prior art”). …” (my emphasis)

So the fact that the problem may change is explicitly mentioned but somewhat left open. More information is provided in C-IV 11.5.1 “Determination of the closest prior art”:

“The closest prior art is that which in one single reference discloses the combination of features which constitutes the most promising starting point for an obvious development leading to the invention. In selecting the closest prior art, the first consideration is that it should be directed to a similar purpose or effect as the invention or at least belong to the same or a closely related technical field as the claimed invention. In practice, the closest prior art is generally that which corresponds to a similar use and requires the minimum of structural and functional modifications to arrive at the claimed invention (T 606/89). …” (my emphasis)

Fortunately, there is no reference to the similarity of technical problem and the first approach mentioned above seems to prevail.

My personal opinion is that this approach is to be privileged and that references to a problem solved should be banned from this stage of the problem-solution approach. 

This being said, once the closest prior art is identified, one can determine an objective problem and the similarity-of-problem approach can be useful in the determination of the prior art to be combined with the closest prior art. It makes sense to use only documents that deal with the same (or at least a similar) technical problem, and there may be more or less promising candidates, considering the objective technical problem. And if the prior art cited in the application or patent is indeed the closest prior art, then the problem mentioned in the application or patent may be the relevant technical problem and is to be taken into account.

Coming back to our decision of the day, I had a look at the decision cited therein, T 506/95. The relevant passage (translated from the German) reads:

“When choosing the closest prior art, it is decisive that its solution is directed towards the same purpose (Zweck) or the same effect (Wirkung), respectively. Otherwise it cannot lead the skilled person to the claimed invention; see T 606/89, T 570/91 and T 1040/93. Mere external similarities – which can be established in retrospect – are not sufficient to qualify a document as closest prior art to an invention. Rather, their suitability for the purpose that the invention serves have to be disclosed or clearly recognizable (cf. T 273/92).” (my emphasis)

Again, it is the purpose that is taken into consideration, and not some sort of hypothetical problem. 

One might object that this is mere word-picking and that there is a purpose to each problem (namely to solve the problem) and a problem to each purpose (to reach the purpose). Still, as we have seen, the case law distinguishes the approaches and indeed they are not completely equivalent. For instance, it is relatively easy to attribute a purpose to the object of a prior use whereas it may be more difficult to determine a problem to be associated with it.

Be that as it may, faulty or not, the reasoning of our decision of the day may serve your case from time to time, so be aware that it exists.

Should you wish to download the whole decision, just click here.

To have a look at the file wrapper, click here.

NB: Should I have overlooked an aspect or got it completely wrong, please leave a comment.