3. Assessment of unity 

The assessment of unity of invention serves to determine if the subject-matter of the claims have anything in common that represents a single general inventive concept (Art. 82). If any of the claims contain one or more alternatives, each of the alternatives is considered as if it were a separate claim for the purpose of assessing lack of unity.

A substantive assessment of unity of invention requires

(i)determining, in the light of the application as a whole, the common matter, if any, between the claims of the different claimed inventions that the examiner provisionally identifies (see F‑V, 2.2, F-V, 3.2 and F-V, 3.4);

(ii)comparing the common matter with the "prior art at hand" to examine whether the common matter makes a contribution over that prior art, namely whether it comprises "special" technical features within the meaning of Rule 44(1);

(iii)if the common matter does not comprise special technical features, analysing any remaining technical features which are not part of the identified common matter to determine if there is a unifying technical relationship among some of the claims. 

For example, lack of unity may arise among the dependent claims if the independent claim upon which they depend does not comprise any features making a technical contribution over the prior art at hand. In such a case, the independent claim would not provide a unifying technical relationship among the dependent claims as required by Rule 44(1) as it would not contain any "special technical features".

(i) Determining the common matter 

Common matter represents a potential single general inventive concept among the claims. It may be present in features which are the same or corresponding (see F‑V, 2), namely in features that are either identical to each other or that provide alone or in combination a common technical effect or a solution to a common technical problem.

The technical problem in the non-unity assessment may be different from that in a patentability assessment since the overall object is to find out what the claims have in common.

When analysing the technical problem in a non-unity assessment, the starting point is usually what is considered by the applicant in the description as having been achieved. In this regard, the applicant must disclose the invention in such terms that the technical problem and its solution can be understood, and state any advantageous effects of the invention with reference to the background art (Rule 42(1)(c)). This technical problem defines in the first instance the common matter of the claims.

However, for the purpose of considering unity of invention, the division is not restricted to the general concept of what the applicant subjectively claims to be his invention (G 1/89 and G 2/89).

The technical problem put forward by the applicant in the description may, on closer examination, reveal itself as unsuitable as a means of linking the subject-matter of the claims in such a way that they form a single general inventive concept. This may happen either where, in view of the information contained in the description and the common general knowledge of the skilled person, it is evident that different claims solve different problems (a priori assessment of lack of unity) or where the search reveals prior art which discloses or renders obvious a solution of the unifying technical problem stated by the applicant in the description (a posteriori assessment of lack of unity). In the latter case, the technical problem stated by the applicant may no longer constitute the single general inventive concept required by Art. 82 since it cannot be regarded as inventive.

For example, a prior-art document under Art. 54(2) disclosing all the features of an independent claim also discloses, at least implicitly, the technical problem stated by the applicant since by definition this problem must be solved by the features of said independent claim.

The division will then proceed to analyse if any other common matter is present among the claims, i.e. identify, in the light of the application as a whole, any technical features of the claims that are the same or corresponding. When determining whether technical features are corresponding, it is important that the technical problems solved, which are associated with the technical effects, are not formulated too narrowly or too generally. If the technical problems are too narrow when they could have been more general, they may have nothing in common leading to the possibly wrong conclusion that technical features are not corresponding. If they are too general when they could have been narrower, the common aspects of the problem may be known, also leading to the possibly wrong conclusion that there is a lack of unity.

For example, a membrane and a diaphragm may achieve the technical effect of "providing resilience" and hence may be corresponding features.

Common matter may not only be found in features of claims in the same category but may also be embodied in features of claims of different categories. For example, in the case of a product, a process specially adapted for the manufacture of said product and the use of said product, the product may represent the common matter which is present in the use and in the process as the effect or result of the process.

Common matter may also be embodied in interrelated product features (e.g. a plug and a socket). Although corresponding features in interrelated products may be formulated quite differently, if in their interaction they contribute to the same technical effect or to the solution of the same technical problem, they may be part of the common matter.

There may be cases where no common matter at all can be identified. Then the application lacks unity because neither a technical relationship within the meaning of Rule 44(1) is present between the independent claims, nor does the application entail a single general inventive concept within the meaning of Art. 82.

(ii) Comparison of the common matter with the prior art at hand 

If common matter, namely subject-matter involving the same or corresponding technical features, is identified in the claims, it must be compared with the prior art at hand. If the common matter defines a non-obvious contribution over that prior art, it will involve "special technical features", and the inventions concerned will be so linked as to form a single general inventive concept. Otherwise, if the common matter is known or obvious from the prior art at hand, then the application lacks unity. This assessment is to be done on the basis of an assessment of novelty and inventive step vis-à-vis the prior art at hand. The obviousness is to be assessed, whenever appropriate, using the problem-solution approach.

The common matter may involve features defining technical alternatives. If the common technical effect to be achieved by these technical alternatives is already known, or may be recognised as generally desirable (a mere desideratum), or is obvious, these alternative features cannot be considered as defining a technical relationship within the meaning of Rule 44(1) because there is no inventive merit in formulating the problem.

The "prior art at hand", i.e. the prior art relied upon in the non-unity assessment, may vary depending on the stage of proceedings. For example, where the assessment is carried out before the search ("a priori assessment"), the only "prior art at hand" may be the background art provided by the applicant in the description and any common general knowledge. During the search, other prior art may be revealed and may form the basis for the "a posteriori assessment". Therefore, the "prior art at hand" may change during the course of the proceedings. For this reason the assessment of unity is iterative.

(iii) Analysis of the remaining technical features 

If the comparison of the common matter under (ii) leads to the finding of a lack of unity, as a next step, the groups of different inventions present in the claims need to be confirmed or refined (see F‑V, 3.2).

In order to determine these groups of inventions, the remaining technical features not forming part of the identified common matter need to be analysed. In most cases, each group will comprise several claims. This grouping is performed on the basis of the technical problems associated with the remaining technical features of each of the claims. Those claims comprising remaining technical features associated with the same technical problem are combined into a single group. However, if the technical problem has been successfully solved in the prior art, claims associated with the same technical problem may be placed into different groups (see F‑V, 3.3.1(iii)(c)).

The technical problems associated with the claims must be formulated with care. It may not be sufficient to analyse the remaining technical features of each claim in isolation, but rather to analyse their effect when read in the context of the individual claim as a whole and in the light of the description. When formulating the technical problems of the various inventions in a unity assessment, a very narrow approach should be avoided since the aim of the exercise is to see whether any commonality may be established between the inventions. It is therefore often necessary to redefine the very specific problems associated with each of the claims to arrive at a more general problem, while bearing in mind the context in which the relevant features are disclosed.

For the grouping, it is irrelevant whether or not the subject-matter of the claims or of the remaining technical features of the claims are novel or inventive over the prior art at hand. However, it is relevant for assessing whether or not the applicant is to be invited to pay an additional search fee for a group (see F‑V, 4).

If the problem(s) associated with the different groups is (are) either known from the prior art at hand or is (are) different from each other, then the finding of step (ii) that there exists a lack of unity is confirmed.