This article considers the circumstances that may give rise to the need to file a divisional patent application, together with the requirements for getting such an application on file. Before delving into the detail, we start by first explaining what a divisional patent application is and what such an application is intended for, before moving on to consider the circumstances that may give rise to the need to file such an application. Further filing details are then explored.

What is a divisional patent application?

A divisional patent application, or simply, a divisional, is essentially a sub-divided part or an offshoot of a first so-called ‘parent’ application. A divisional is directed towards part of the subject-matter contained in the parent application and therefore provides the applicant with the option to divide a parent application into a number of sub-divided applications or divisionals, which can then be prosecuted independently of each other.

Advantageously, any divisional filed is accorded the same filing date as the parent application and has the same right of priority of the parent application for subject-matter contained in the divisional. A first European patent application may give rise to a number of divisionals and a single divisional may have a number of divisionals of its own.

In what circumstances may a divisional patent application or divisional need to be filed? And what are the advantages of doing so?

Any application for a European patent must relate to a single invention only, or to a group of inventions so linked as to form a single general inventive concept. The underlying principle here is that there is that the application has unity of invention, that is, all of the claims are linked so as to form the single inventive concept. Claims of the same category (i.e. apparatus or method claims) are allowed, providing that they contain features which are common to each invention or inventive concept.

Unity of invention is first considered during the search of a European patent application, whether this is by the Search Division of the European Patent Office (EPO) in the case of a direct-filed European patent application or by the EPO acting as the International Search Authority (ISA), in the case of an international patent application.

Where a lack of unity is found, the application must be split up, or divided into one or a number of divisionals, such that the first application relates only to a single invention. The benefit of filing divisionals therefore is that subject matter which had to be deleted from the parent application can be further prosecuted as a separate application. This is of course important where the grant of a patent to the second and subsequent inventions is of commercial value, and thus a divisional provides a mechanism by which this can be achieved.

One case to note is where an international patent application subsequently enters the European regional phase. In this situation, where lack of unity of invention is found during the international search in the international phase, although it is possible to pay additional search fees, such that a second and subsequent invention or inventive concept may be searched, only a single invention can be pursued in the first application and divisional(s) must be filed as a normal course of action.

When can a divisional patent application be filed?

The overriding principle is that a divisional may only be filed when the parent application is pending. This is important. The parent application is pending up to (but not including) the date on which the European Patent Bulletin mentions the grant of the European patent, or the date on which the application is refused, withdrawn or deemed to be withdrawn. If an application is refused, it is considered still to be pending until the expiry of the period for filing an appeal, that is, before the refusal becomes final. In view of this, if a notice of appeal is filed, there is a suspensive effect, and a divisional may still be filed until the decision and outcome of the appeal becomes final.

Providing the parent application is pending, there are two time periods for filing divisionals: a voluntary time period and a mandatory time period.

Voluntary time period

A divisional may be filed on the basis of a pending parent application before the expiry of a time limit of twenty-four months from the Examining Division’s first communication in respect of the earliest application for which a communication has been issued. Generally, only a communication pursuant to Article 94(3) EPC is relevant (an Examination Report), but a communication pursuant to Rule 71(3) EPC is also relevant, where it is not preceded by a communication pursuant to Article 94(3) EPC.

Mandatory time period

A divisional may be filed on the basis of a pending parent application before the expiry of a time limit of twenty-four months from any communication in which the Examining Division has objected that the earlier application does not meet the requirements of unity of invention (Article 82 EPC), provided it is the first time that such an objection is raised. Where the mandatory time period expires later than the voluntary time period (see above), a divisional may be filed by the expiry of the later period. So importantly, this time period applies to the situation where lack of unity of invention is raised for the first time, or where it confirms a previous finding already raised during the European or international search (or supplementary European search, where the EPO was not the ISA during the international phase).

It is important to note that the above-mentioned time periods are final and cannot be extended, once expired, except in the case where the patent application is refused and an appeal has been filed.

What are the filing requirements for getting a divisional patent application on file?

It is important to note that a divisional may only be filed by the applicant of the parent application and where the parent application is filed in the name of joint applicants, any divisional must also be filed in the same, joint applicants, names. Of course, a transfer of ownership can be carried out and recorded, but this must be completed before any divisional is filed.

The content of a divisional may not extend beyond the subject-matter of the parent application, and providing this requirement is met, the subject-matter of the divisional is deemed to have been filed on the date of filing of the parent application, although it is possible to amend a divisional to delete any subject-matter which is found to extend beyond that of the parent application.

All divisionals must be filed directly with the EPO, and importantly, at one of the filing offices (i.e. Munich, The Hague or Berlin), by hand, post or fax, or other electronic means, such as online filing.

As divisionals are treated in the same way as any ordinary application, they are subject to the same requirements, and thus a request for the grant of a patent must be included on application. A divisional must be filed in the language of the earlier application, or alternatively, if the earlier application was filed in a language other than an official language of the EPO, then this language may be used, and a translation provided within two months of filing.

Payment of the filing fee and search fee must be made on filing, or at the latest within one month of the filing date. Again, as the same requirements relating to an ordinary application apply, an excess pages fee is payable in respect of all divisionals having pages in excess of 35 and excess claims fees apply in the case where claims in excess of 15 are filed. Examination and designation fees must be paid within six months of the date on which the European Patent Bulletin mentions the publication of the European search report drawn up in respect of the divisional. Finally, any renewal fees that have fallen due (back payments) in respect of the earlier application are due when filing the divisional.