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Assessment of unity of invention

Lack of unity a posteriori

6.27 Unity of invention will be present when the claims all have the same or corresponding “special technical feature” that provides the contribution over the prior art. However, in some cases it may be apparent that the common or corresponding feature does not provide a contribution over the prior art. This will most often occur where a preliminary search identifies documents that disclose the common or corresponding feature. In such cases, an objection to lack of unity may be applicable on the basis that the claims have no common or corresoponding technical feature that makes a contribution over the prior art (that is, a posteriori – after taking the prior art into account).

6.28 In many cases the lack of unity will be apparent to the Examiner from an initial consideration of the claims, and the key consideration will be as to whether an a priori approach is the most appropriate or whether an a posteriori approach should be taken. Where an a posteriori approach is considered appropriate, an initial search can be carried out to target the matter in common between the claims.

6.29 A posteriori lack of unity may be illustrated as follows:

1. A + X
2. A + Y

In the case of independent claims A + X and A + Y which have feature A in common, if it is established after a search that A is not novel or is obvious, there may be a lack of unity a posteriori, since A (be it a single feature or a group of features) is not a technical feature that defines a contribution over the prior art. Each of these groups is taken to be a separate invention.

6.30 However, there will be instances whereby the Examiner discovers, only after a search,  that the common feature is well known in the art. In such cases, an a priori lack of unity objection may be raised. It is noted that the tests for assessing unity, whether a priori or a posteriori, are meant to assist Examiners in performing the unity assessment and formulating its associated reasoning. When raising a unity objection in the written opinion or in the examination report, the Examiner may specify whether the lack of unity occurs a priori or a posteriori, although he need not do so.

6.31 The a posteriori approach is most applicable in situations where the “real” inventions are unrelated but the manner in which the claims are drafted introduces a common feature that is not essential to each. A simple example of this is the following:

1. Automobile characterised by a new and novel exhaust system.
2. Automobile characterised by a new and novel engine cooling system.

In this case, the “real” inventions relate to the exhaust system and the cooling system respectively. If a search identifies prior art documents that disclose the common feature of the automobile, an objection of lack of unity a posteriori may be taken. This is consistent with the policy intention that unity is intended to assist with the efficient administration of the patent system: the two real inventions would require entirely separate searches and examinations, and would be subject to entirely different infringement and revocation actions. On the other hand, if it is determined, whether or not such determaination involved a search of the prior art, that the common feature of the automobile is well known, an objection of lack of unity a priori may be appropriate.

6.32 Some other examples of these types of situations would be:

1. A batch stirred tank reactor comprising Catalyst X for use in the preparation of compound Z.

2. A batch stirred tank reactor comprising Catalyst Y for use in the preparation of Polymer A.

If Catalyst X and Y and/or compound Z and Polymer A were unrelated, then the only feature in common would be the batch stirred tank reactor. If a search identifies prior art documents that disclose the common feature of the batch stirred tank reactor, then an objection of lack of unity a posteriori may be taken. On the other hand, if this type of reactor is well known in the art, then an objection of lack of unity a priori may be taken.

6.33 If an independent claim is new and inventive (i.e. a special technical feature is defined in the claim), then it follows that dependent claims will be unified. This will be the case even if the additional features defined in the appended claims are prima facie routine or obvious by themselves or are prima facie directed to different inventive concepts. For example, in the following claims, if A + B is found to be novel and inventive and the combination of these features represents a special technical feature, then Claims 2 and 3 will have unity with Claim 1 even if features C and D are well known in the art.

1. A + B
2. A + B + C
3. A + B + D

6.34 If the combination of A + B was not novel, then an a posteriori lack of unity could result. In this sort of situation, the decision to raise unity would take into account all circumstances of the case. If, in the opinion of the Examiner, the separate combination with C and D results in different inventions, then a unity objection may be raised. However, if the combination of A + B was known in the art and there was clearly no inventive step in adding either of the features C and D, then the unity objection may be a mere technicality.

6.35 For the combination of A + B, an a posteriori lack of unity in view of a combination of documents is generally not recommended unless the motivation for combining the documents is absolutely clear. Otherwise raising an objection to a lack of unity may lead the applicant to argue an absence of motivation to combine the documents, which is better dealt with in the inventive step assessment.