What is unity of invention?

Unity of invention requires that the claims of a patent application must relate to a single invention, or to a group of inventions linked by a “single general inventive concept”. Unity of invention is a requirement within UK and European patent applications, and ensures that each patent only covers a single invention.

A group of inventions share a “single general inventive concept” if the inventions, as defined by the claims, have the same or corresponding technical features. In other words, the group of inventions must all share inventive features that achieve the same technical effect or solve the same technical problem.

An example of a group of inventions that share a single inventive concept include a group of interrelated products – for instance, a plug and a socket that have a novel and inventive cooperating connection feature. In contrast, a set of claims having a first independent claim directed to a novel bicycle braking system, and another independent claim directed to a new type of bicycle bell would not be considered to be linked by a shared inventive concept. Instead, these could represent two separate inventions.

When may a unity objection be raised?

The claims of a patent application may be found to lack unity during the search phase. This is sometimes, but not always, the case if an application contains more than one independent claim in the same category (i.e. apparatus, method). In some circumstances, a lack of unity of invention may only become apparent after the relevant prior art has been identified. This may arise if an independent claim is considered to lack novelty and inventive step in view of the identified prior art, but more than one non-compatible features within the dependent claims each could be considered to define an invention.

How can a unity objection be rectified?

If a lack of unity of invention is identified within a UK or European patent application during prosecution, the claims of the application must be amended to define only a single invention. Nevertheless, patent protection can be pursued for any other described invention by filing a Divisional application. Any Divisional application must be filed whilst the earlier application is still pending (in other words, before grant or final refusal of the earlier application). However, in Europe and the UK further Divisional applications may be filed from an earlier pending Divisional application, even if the earliest application is no longer pending.

When is unity of invention relevant?

Unity of invention is only of relevance to pre-grant proceedings. Therefore, a lack of unity of invention is not a ground for revocation of a UK or European patent after grant. Furthermore, a patentee should not be prevented from amending a granted patent during European opposition proceedings, even if the amendment leads to a lack of unity of invention.