What is a divisional patent application?

Divisional patent applications and when to file them

Although the rules vary between jurisdictions, many patent systems allow applicants for patents to file “divisional patent applications” while their earlier (“parent” or “base”) patent application is pending.

What is a divisional patent application?

A divisional patent application is a patent application which is “divided out” from the parent application. It is not possible to add subject matter when filing a divisional patent application, but it is possible to seek protection for subject matter that appeared in the parent patent application. There are several possible reasons why an applicant might wish to file a divisional patent application. To give just a few examples, an applicant might file a divisional patent application:

• Because the earlier application has been found to lack "unity", i.e. to include claims directed to more than one invention;
• Because the applicant wants to seek protection for subject matter which appears in the specification but not in the claims of the earlier application; or
• Because the applicant wants to seek protection for claims having broader claim scope than those of the earlier application.

Once filed, the divisional patent application is independent from the parent patent application. However, for the purposes of assessing novelty and inventive step, divisional patent applications are treated as having the same filing date (and usually the same priority date(s)) as the parent patent application.

Divisional patent application prosecution proceeds in the same way as for any other patent application. The Patent Office will carry out their normal search and examination procedures and will issue communications to the applicant and report their findings and raise any objections. Eventually, if all objections are addressed, the divisional patent application will proceed to grant, resulting in a patent independent from the original parent patent application (and any patent granted for the parent patent application).

To consider the above unity point further, most countries require that a granted patent may only include claims relating to a single invention. However, patent applications often describe more than one invention, and sometimes have claims directed to several inventions. Protection can be sought for the additional inventions by filing one or more divisional patent applications. Accordingly, divisional patent applications are commonly filed to overcome an objection that the claims of the parent patent application lack unity. Some of the subject matter of the parent patent application is divided out, resulting in two patent applications: The original parent patent application which is directed to one invention, and the new divisional patent application which is directed to a different invention.

What are the filing requirements for a divisional patent application?

In the UK and Europe, there are three main requirements for filing a divisional patent application:

1. The divisional patent application must be filed by the same applicant (or their successor in title);

2. The divisional patent application may only contain subject matter which does not extend beyond the content of the earlier patent application as filed (i.e. it is not possible to introduce new subject matter); and

3. The divisional patent application must be filed while the earlier patent application is still pending (i.e. before it is finally granted, refused, withdrawn, or abandoned, and not when the earlier patent application is deemed to be withdrawn).

In addition, in the UK, any divisional patent application must be filed at least 3 months before the end of the “compliance period” (which is the later of 4.5 years from the filing date or priority date of the parent patent application, or 12 months from the issuance of the first substantive examination report for the parent patent application).

Other requirements vary from jurisdiction to jurisdiction. For example, some Patent Offices specify that a divisional patent application can only be filed in response to a finding of lack of unity of the parent patent application. In some jurisdictions, it is sufficient if at least one (and not necessarily all) of the applicants for the parent patent application is also an applicant for the divisional patent application.

Why might I want a divisional patent application?

As alluded to above, a common reason to file a divisional patent application is to seek protection for claims which were found to relate to additional inventions (i.e. where an objection is raised that the claims of the patent application are not unified).

However, there are many reasons why an applicant might wish to file a divisional patent application. For example, applicants also sometimes file divisional patent applications where they would like to seek protection for subject matter that appears anywhere else in the parent patent application but not in the claims that are expected to proceed to grant.

In another example, applicants sometimes make amendments to their claims in order to get a patent granted quickly, but the amendments make the claims narrower than the applicant would prefer. The applicant might file a divisional patent application in such a case, to try to get protection for broader subject matter.

In such a case, if the parent patent application is going to grant, and during prosecution claim 1 has been amended to read (where the underlined text indicates an amendment made after filing):

A widget comprising features A, B and C, wherein feature C is of variety X.

Then the applicant might want to file a divisional application where claim 1 reads:

A widget comprising features A, B and C.

It would be quite likely for the applicant to the receive the same objections as prompted them to amend the parent patent application. In which case, they could argue against these objections, or make some other amendments. Either way, they would have the option to proceed more slowly with their divisional patent application and more quickly with their parent patent application.

Here, with the divisional patent application, the applicant could seek protection for other features, or for broader features. Perhaps they might specify something about feature A or B instead of feature C. Alternatively, perhaps they might specify something different about feature C. In the end, the intention is to obtain two or more patents with similar (but not identical) scopes of protection, in order to obtain broader protection with a portfolio of patents than was possible with just one patent.

Applicants sometimes also file divisional patent applications to try to limit the activities of known competitors. For example, if an applicant has a parent patent application with a specification that happens to describe features of their competitor’s product, the applicant could keep the parent patent application with claims directed to the applicant’s own product, and could file a divisional patent application to try to seek protection for the features of their competitor’s product. This can then put the applicant in a better position for negotiating with their competitor.

Further to this, a divisional application can be a good way for an applicant to keep a patent application pending when the parent application is going to be granted or refused. This can be a helpful tactic, particularly because the scope of protection of a patent application is uncertain because the claims can be amended while a patent application is still pending. From this point of view, filing a divisional application increases uncertainty for third parties, who will have to wait until all applications have been granted or refused before they can fully assess whether their planned activities would infringe any particular claim. In general, it can be advantageous to have an application pending for this reason.

In some cases, divisional patent applications might also be filed so that different aspects of the patent application can be assigned to different parties. Because a divisional patent application is independent from the parent patent application, once it is filed it is possible to assign or license the divisional patent application without carrying out the same step for the parent patent application. So, for example if an applicant has filed a parent patent application containing two ideas, and they want to assign rights in one of those ideas to a third party, they could file a divisional patent application directed to the relevant idea and then assign the divisional patent application to the third party.

As mentioned above, not all of these options are possible in all jurisdictions, but all are possible before the UKIPO and the EPO.

Divisional applications and patent filing strategy

Although it is sometimes frustrating to be required to file a divisional application, there are occasions when a patent application will have been filed knowing that it relates to more than one invention and that a requirement to file one or more divisional patent applications was likely. This strategy is sometimes useful to defer the cost of obtaining multiple patents, or where the applicant is uncertain as to how likely they are to obtain a patent for one or more inventions.

Generations of divisional applications

In the UK and Europe, it is also possible to file second and subsequent generational divisional patent applications. For example, in some cases, an applicant might have a parent patent application pending, file a first divisional patent application based on the parent patent application, and then file a second divisional patent application based on the first divisional patent application, and so on.

This is helpful, because in the UK and Europe (and many other jurisdictions) it is only possible to file divisional patent applications while a higher generation patent application is pending. Accordingly, if the parent patent application is no longer pending, but a divisional patent application was filed and is still pending, it is still possible to file a further divisional patent application. That said, in the UK, applicants should be aware that the compliance period also puts a limit on filing additional divisional applications (see above). This also means that it is a good idea to include all of the subject matter of the earlier patent application in each divisional patent application. Doing so will mean that all of that subject matter is available in the divisional application and thus can be used to provide the basis for claims for a further divisional application.

It should also be noted that there are some countries where a divisional application can only be filed while the initial patent application is pending, and it is not sufficient that another divisional application remains pending.

What are the costs?

In many jurisdictions, the official fees for a divisional patent application are the same or similar to those for an ordinary patent application.

Notably, the case is different for European patent applications for two reasons. Firstly, because second and subsequent generations of divisional patent applications attract an extra “divisional patent application fee” on top of the ordinary filing fee. Secondly, because “back-dated” renewal fees fall due for the divisional patent application, dated back to the filing date of the parent patent application.

Designated European states

Where the parent patent application was a European patent application, all the states designated in the parent patent application at the time of filing the divisional patent application are deemed to be designated in the divisional patent application as well. Accordingly, care should be taken if designations are to be withdrawn, to make sure that this does not happen before any planned divisional patent applications are filed, unless it is accepted that the designations should also be withdrawn for the divisional patent applications.

Continuation patent applications and divisional patent applications in the US

The US patent system allows the filing of both divisional patent applications and continuation patent applications (not to be confused with “continuation-in-part” patent applications). While the two types of patent application are similar, there are some important differences to keep in mind.

Both US continuation patent applications and US divisional patent applications have the same priority date and filing date as the US parent patent application, and both require that at least one inventor for the parent patent application is also listed as an inventor for the continuation or divisional patent application. As with most other jurisdictions, US continuation and divisional patent applications can only be filed while the parent patent application is still pending.

A US divisional patent application is normally filed in response to a “Restriction Requirement” being issued by the Examiner. US patent Examiners issue Restriction Requirements where they consider that the claims of the parent patent application lack unity. In response, the applicant must choose one invention and cancel the claims to the other invention(s) (or convincingly argue that the claims are in fact unified). The applicant may then file a divisional patent application directed to the cancelled claims. As for divisional patent applications in other jurisdictions, it is not possible to introduce new subject matter when filing a US divisional patent application.

A US continuation patent application allows the applicant to introduce new claims which did not appear in the parent patent application, or to seek protection for claims which were in the parent patent application but which were later narrowed or removed. For example, an Examiner might indicate that some claims of the parent patent application are allowable, but others are rejected. In this case, it can be advantageous to cancel the rejected claims in the parent patent application and to file a continuation patent application directed to those rejected claims. This way, the parent patent application can proceed to grant while the applicant continues to pursue protection for the rejected claims (whether by arguing that the claims should be allowable, or by making amendments, or both).

Although filing a continuation patent application allows the introduction of new claims, it also does not allow the introduction of new subject matter, so it is necessary that the claims of the continuation patent application can be derived from the specification of the parent patent application.

Designs

In some countries, it is possible to file divisional applications on the basis of applications for registered designs or design patents. Notably, this includes the US and Canada. Normally, this would only happen where a design application has been filed which includes several different embodiments of the design, and an Examiner has objected that the different embodiments are not in fact all representative of the same design.

To proceed with the application, the applicant then needs to decide on one of the embodiments for the initial design application, and to delete the other embodiments. If they wish, the applicant can also file one or more divisional design applications to seek protection for the other embodiments.

In some cases, applicants may wish to file design applications that include multiple embodiments even if such an objection is anticipated, because the Examiner may find fewer different designs amongst the various embodiments than the applicant might have expected. Accordingly, this can reduce costs compared to filing several separate design applications in the first instance.

Conclusion

By filing divisional patent applications, an applicant can end up with a collection of patents, each protecting different subject matter. In total, this collection of patents provides a broader scope of protection than would be available with just one patent. As most patent systems require that one patent may include only one invention, this is particularly helpful where a patent application includes information about multiple ideas or inventions.

If you have any questions about divisional patent (or design) applications, please ask your usual contact at Hindles.