A Review of the “Problem and Solution” Approach to Inventive Step under Article 56 EPC

A. Kennington

This is the first part of a long article, which will be published in three parts in successive issues of epi Information.

Introduction

The problem and solution approach is used almost universally at the EPO in the examination of inventive step. Over the years, there has been extensive case law from the Boards of Appeal concerning the correct way to use this approach. However, difficulties can still arise. I believe that some of these difficulties can be avoided, and a clearer understanding of the principles that should underlie this approach can be obtained, from a review of the legal status of the problem and solution approach and a consideration of the provisions of the EPC relating to inventive step.
Inventive step is defined in the EPC by Article 56 as follows:

An invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art. ...

This is the only definition of inventive step given in the EPC. It does not mention the problem and solution approach. The test for inventive step, according to the EPC, is solely that the invention should not be obvious having regard to the state of the art.

The state of the art is in turn defined in the EPC by Article 54(2), which reads as follows:

The state of the art shall be held to comprise everything made available to the public by means of a written or oral description, by use, or in any other way, before the date of filing of the European patent application.

Thus an invention involves an inventive step if it is not obvious to a skilled person having regard to everything made available to the public (in any way) before the relevant date.
The problem addressed by the invention, and the solution provided to it, are not mentioned in the text of the EPC itself, but are mentioned in three places in the Implementing Regulations of the EPC, in Rule 42 (content of the description), Rule 43 (form and content of the claims, in sub-rule (2) relating to multiple independent claims in the same category), and in Rule 47(1) (content of the abstract). Attention is normally focussed on Rule 42, the relevant part of which reads as follows

(1) The description shall:
...

(c) disclose the invention, as claimed, in such terms that the technical problem, even if not expressly stated as such, and its solution can be understood, and state any advantageous effects of the invention with reference to the background art;
...

It should be borne in mind that this is a provision relating to disclosure in the description, and not the definition of inventive step.
Thus the wording of the EPC assumes that an invention will inevitably provide a solution to a problem, but it does not require the use of the problem and solution approach in assessing inventive step and it does not establish the problem and solution approach as a test for, or a definition of, inventive step. The only test for, and definition of, inventive step given in the EPC is that the invention is not obvious having regard to the state of the art (everything made available to the public).
These observations do not imply any criticism of the EPO for relying on the problem and solution approach. On the contrary, it is a highly useful method of analysis in assessing inventive step, and its use is widely approved in the case law of the Boards of Appeal. However, it is important that the problem and solution approach is regarded as a tool to be used in the assessment of inventive step, and not as a definition of inventive step that can be used as a substitute for the actual requirements of Article 56 EPC. Therefore care should be taken to ensure that the problem and solution approach is always implemented in a manner that is consistent with the requirements of Article 56 EPC.
Therefore a focus on the requirements of Article 56 EPC may be helpful in ensuring the correct formulation of the problem and may also be helpful in the selection of the starting point (the so-called "closest prior art") for the analysis of inventive step.

Formulation of the Problem

Often, an argument that a claimed invention is or is not inventive starts from a statement of the problem, and focuses on whether the claimed product or process is or is not an obvious solution to the problem, given the disclosure in the prior art. However, this approach does not correspond precisely to the requirements of Article 56 EPC. Article 56 EPC states that an invention has an inventive step if it is not obvious "having regard to the state of the art". It does not state that the invention has to avoid being obvious "having regard to the problem". Consequently, if an argument seeks to determine inventive step by asking whether the solution is obvious, it must be based on an appropriate formulation of the problem if it is to be in accordance with Article 56 EPC. If the problem is wrongly formulated, so as to contain the claimed solution or pointers to it, the solution may be obvious from the stated problem even if there is in fact an inventive step over the prior art. Therefore the problem and solution approach to inventive step can be misleading if the problem is not formulated correctly.

This issue is well known. Part G-VII, 5.2 of the Guidelines for Examination in the European Patent Office states, referring to Technical Board of Appeal decision T 229/85,

It is noted that the objective technical problem must be so formulated as not to contain pointers to the technical solution, since including part of a technical solution offered by an invention in the statement of the problem must, when the state of the art is assessed in terms of that problem, necessarily result in an ex post facto view being taken of inventive activity.

Similarly, Board of Appeal decision T 800/91 stated

In any case the formulated problem should be one which the skilled person would wish to solve knowing only the prior art: the problem should not be tendentiously formulated in a way that unfairly directs development towards the claimed solution. (Reasons for the Decision, part 6)

However, these exhortations from the Boards of Appeal do not provide an easy rule by which to determine whether a particular formulation of the problem is permissible. The problem and solution approach is supposed to be based on the "objective technical problem", that is determined by the difference between the closest prior art and the invention as claimed, but it is still not clear exactly how to formulate the problem without including pointers to the solution. It is not always easy to reconcile guidance from different Board of Appeal decisions.
For example, decision T 910/90 refers to the objective technical problem and states

Dabei kommt es nicht darauf an ob diese Aufgabe bereits im nächstkommenden Stand der Technik angesprochen ist, sondern darauf was der Fachmann beim Vergleich des nächskommenden Standes der Technik mit der Erfindung als Aufgabe objektiv erkennt. (Reasons for the Decision part 5.1)
(Unofficial translation – It does not matter whether this problem is already mentioned in the closest prior art, but rather what the skilled person objectively recognizes as the problem when comparing the closest prior art with the invention.)

while decision T 967/97 states

Der Aufgabe-Lösungs-Ansatz beruht im wesentlichen auf tatsächlichen Feststellungen über technische Aufgaben und Wege zu deren technischer Lösung, die dem Kenntnisstand und Können des Fachmanns objektiv, d. h. ohne Kenntnis der Patentanmeldung und der Erfindung, die sie zum Gegenstand hat, zum Prioritätszeitpunkt zuzurechnen waren. (Reasons for the Decision part 3.2)

(Unofficial translation – The problem-solution approach is essentially based on actual findings about the technical problems and approaches to their technical solutions arising from the knowledge and skills that the skilled person possesses objectively, i.e. without any knowledge of the patent and the invention with which it is concerned, at the priority date).

It seems that decision T 910/90 could imply that the problem can be formulated by taking the invention into account and there is no need for the skilled person to reach the problem starting only from the state of the art. If decision T 910/90 is interpreted in this way, it would appear to be incompatible with decision T 967/97. This illustrates some of the confusion that can still arise when trying to define the correct way to formulate the problem. Therefore, although it is well established that the formulation of the problem must not include pointers to the solution, there is still considerable scope for disagreement over what constitutes a pointer to the solution and considerable uncertainty over how to establish whether a formulation of the problem is permissible or not.

In seeking to clarify this point, I propose to start by suggesting that the formulation of the problem must not itself be inventive. This appears to be axiomatic. If the formulation of the problem is itself inventive then even an obvious solution to the problem would be an invention over the prior art. This point was appreciated in decision T 0002/83, which referred to the concept of the "problem invention" in which the invention lies in the identification or recognition of a problem, the solution being obvious once the problem is identified but not being obvious from the prior art alone. This was also recognised in the Guidelines for Examination in the European Patent Office up until 2009 in the discussion of the origin of an invention (originally in part C-IV, 9.4, and later in part C-IV, 11.6), but it has been removed from the 2010 edition onwards (where the relevant discussion was moved to part C-IV, 11.9. It is at part G-VII, 9 in the 2012 and subsequent editions).

More generally, the problem and solution approach seeks to establish that a claimed invention lacks inventive step by linking it to the state of the art by the chain "state of the art – problem – solution/invention". If this approach is to be consistent with Article 56 EPC, which requires obviousness over the state of the art, then each link in the chain must be obvious. If every link in the chain is obvious, the claimed invention lacks inventive step. If any link is not obvious, then the argument fails to show that the claimed invention lacks inventive step because it has not established obviousness having regard to the state of the art.

Therefore if one is seeking to test inventive step by asking whether the invention is an obvious solution to the problem, it is necessary to use an obvious formulation of the problem. This arises directly from to the definition of inventive step in Article 56 EPC. In this way, it is possible to derive the rule that the problem and solution analysis of inventive step is only valid if the problem is formulated in such a way as to be obvious (or known) in view of the state of the art.

In many cases, this rule will be relatively easy to apply, and it allows one to determine whether the problem has been correctly formulated or whether a pointer to the solution, or other impermissible matter, has inadvertently been incorporated into the formulation of the problem.

According to this proposed rule, if an analysis of inventive step uses the problem and solution approach, but the analysis relies on a problem that is not obvious having regard to the state of the art, then that analysis is not valid. In this case, it will be necessary to reformulate the problem. It will normally be possible to formulate a less ambitious problem that is obvious. In general, the problem "can I improve this?" will almost always be obvious even if there is no more specific obvious problem. The challenge then becomes to formulate a problem that is obvious over the state of the art, and which also has an obvious solution that leads to the claimed invention.

Combining Prior Art Disclosures

When applying this rule, it is worth remembering that Article 56 EPC refers to obviousness "having regard to the state of the art" in general, and not obviousness "when applying the state of the art to the closest prior art". Thus a problem may still be obvious having regard to the state of the art in general, even if it is not obvious from the starting point document alone. Suppose that an argument of lack of inventive step is being made, starting from document D1. When considering D1 in isolation, it may not be obvious that there is a problem with its technical disclosure. However, a consideration of D2 may make it obvious that there is a problem with D1, and the solution to that problem may also be obvious. In this case, both the problem and the solution are obvious having regard to the state of the art as a whole, and so there is no inventive step.

This point, that the problem needs only to be obvious in view of the state of the art as a whole, and does not need to be evident from the starting point disclosure, is similar to the conclusion of the US Supreme Court in KSR v Teleflex. In that case, a patent was attacked by saying that it was obvious to solve a problem that arose in the disclosure of a first document by taking a feature from the disclosure of a second document. The Court of Appeals for the Federal Circuit rejected that argument on the grounds that the prior art documents did not address the precise problem that the patentee was trying to solve, and therefore the skilled person would not have a motivation to combine them. The Supreme Court reversed this conclusion, on the grounds that this approach to motivation was too restricted. Instead, any need or problem known in the relevant art can provide a reason for combining the features of the different prior art disclosures. Similarly, in the problem and solution analysis, the formulation of the problem can draw on any motivation that is known (or is obvious) to the skilled person having regard to the state of the art. It is not necessary that this motivation is present in the closest prior art. Additionally, it may be unrelated to any motivation or advantage mentioned in the patent or application in suit.

In principle, the problem and the solution may be made obvious by different prior art disclosures, but this situation requires that care should be taken to ensure that it is obvious to combine all the different disclosures. For example, if D1 discloses some particular arrangement, D2 may indicate that there is a problem with the arrangement of D1 but fail to suggest any solution. A third disclosure D3 may provide a solution to the problem. In this case, D1 is being combined with D2 to identify the problem and D1 is being combined with D3 to identify the solution. Consequently, D2 is being combined indirectly with D3, and it is necessary to ensure that there is nothing in the disclosures of D2 and D3 that would make their combination inventive. For example, D2 might indicate only that there is a difficulty with the arrangement of D1 in a particular context, and the disclosure of D3 might not apply in that context. In this case, the problem, if correctly formulated, would be a desire to modify D1 to overcome the difficulty in the context referred to in D2, since it is only this more restricted problem that is made obvious by the disclosure of D2. Consequently, it might not be obvious to adopt the solution proposed by D3.

In conclusion, the problem used in the problem and solution approach should itself be obvious, but it only needs to be obvious in view of the state of the art as a whole, and it is not necessary that the problem is obvious having regard to the closest prior art taken in isolation.

Selection of the Starting Point
("Closest Prior Art")

The problem and solution approach generally requires the identification of a single piece of prior art as the starting point. The problem then provides the motivation for the skilled person to modify the starting point. If an obvious problem motivates a skilled person to modify the starting point in an obvious manner so as to provide something falling within the scope of the claim, the claim lacks inventive step. The starting point is sometimes referred to as the "closest prior art", and it is possible to expend considerable effort in identifying which, out of several potential starting points, is the "closest". In my view, a consideration of Article 56 EPC shows that this may not always be necessary.

Article 56 EPC does not require that the invention should not be obvious "having regard to the closest prior art". It requires that the invention should not be obvious "having regard to the state of the art", and the state of the art is defined in Article 54 as everything made available to the public. Therefore, in order to establish obviousness it is merely necessary to start from the state of the art as a whole, and not from some particular "closest" prior disclosure. Thus, if there are several potential starting points for an obviousness argument, any of them can be used. If the claim is obvious starting from one item of prior art, then the claim lacks inventive step. It does not matter if the claim is not obvious starting from some other item of prior art, even if that other item of prior art is theoretically "closer". In practice, it may be possible to show an obvious path to the claimed invention from each of several starting points, in which case the claim lacks inventive step in view of each path separately (and any amendment needs to deal with all of them). See for example decisions T 0969/97 (Reasons part 3.2) and T 1514/05 (Reasons part 3.1.6).

Consequently, it can be seen that there is no need to conduct a lengthy analysis to determine which item of prior art is theoretically "closest", and there is no such thing as the "wrong" starting point. If a search reveals several potential starting points for an obviousness argument, it is permissible to consider each potential starting point in turn. If an obviousness argument can be made out starting from any one of them, the claim lacks inventive step, and it is not necessary to decide whether that particular starting point is the closest.

Although the technically closest prior art is often the most promising starting point, this may not be the case in some instances. For example, it may be the case that only a single, technically straightforward, modification to the disclosure of prior art X is necessary to reach the invention, but this modification is not obvious, whereas it may be necessary to make three modifications to the disclosure of prior art Y to reach the invention but all of these modifications are obvious to do. In this case, prior art X might be considered to be technically "closer", but prior art Y makes the better starting point for an analysis of inventive step. The definition of inventive step in Article 56 EPC, which refers only to obviousness having regard to the state of the art, makes it clear that an argument starting from prior art Y is acceptable. The concept of the "closest" prior art in the problem and solution approach can often be useful, but it should not become an artificial constraint on the selection of the starting point for an argument of lack of inventive step.

Treatment of Non-Technical Features

Earlier in this article a rule was proposed that the problem and solution analysis of inventive step is only valid if the problem is formulated in such a way as to be obvious (or known) in view of the state of the art. It is necessary to consider how this rule might affect the way in which non-technical features in a claim are treated during the assessment of inventive step.

As discussed in G03/08, the current approach at the EPO to the admissibility of claims containing non-technical features in a claim (sometimes called the "any hardware" approach) developed over time. It began in Board of Appeal decision T 1173/97 IBM (1 July 1998) with the initial break from the previous "technical contribution" approach and developed to the position set out in Board of Appeal decision T 0424/03 Microsoft (23 February 2006).

Alongside the "any hardware" approach to the admissibility of claims containing non-technical features, the EPO follows an approach to the inventive step of such claims that is often referred to as the Comvik approach, with reference to Board of Appeal decision T 0641/00 Comvik (26 September 2002). The Comvik approach requires that an inventive step can only be provided by technical features (or non-technical features that nevertheless combine with technical features to provide a technical effect). Therefore, under the problem and solution analysis, any non-technical features that do not contribute to a technical effect cannot be regarded as part of the solution to the problem.

Decision T 0641/00 Comvik proposed that non-technical features of a claim could be included in the problem, as a constraint that has to be met. The problem was formulated to include such features even though they were not known in the art. This practice of including novel non-technical features in the problem as a constraint to be met appears to be incompatible with the proposal above that the problem must be known or obvious having regard to the state of the art. Consequently, it is necessary to review the case law to understand how and why this practice arose, and whether it is really incompatible with the present proposal. This will be the subject of part 2 of this article.