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18 March 20248 minute read

What is a forced ‎divisional and when are you protected from double ‎patenting in Canada?‎

A patent may be granted for one invention only pursuant to subsection 36(1) of Canada’s Patent Act. Where multiple inventions are claimed in an application, the applicant may choose to divide the claims into separate applications or must do so on direction from the Commissioner of Patents. Otherwise, the patent may be at risk of becoming invalidated for double patenting. However, the Supreme Court of Canada in Consolboard established that enforced divisional applications should not prejudice the applicant. As the Court noted:

If patents are granted on divisional applications directed by the Patent Office, none of them should be deemed invalid, or open to attack, by reason only of the grant of the original patent. (Consolboard at 537)

Accordingly, it is important to determine whether a divisional application is “voluntary” or “directed by the Patent Office” (commonly referred to as a “forced divisional”) to assess whether a patent would be immune or vulnerable to double patenting attacks. However, recent decisions at the Federal Court have cast doubt on what a forced divisional application actually is for the purpose of being shielded from allegations of double patenting, or even if such a thing exists.

Divisional patents

Since October 1, 1996, section 36 of the Patent Act  makes a distinction between a “voluntary” divisional application and a forced divisional application filed at the direction of the Commissioner. Subsections 36(2) and 36(2.1) of the Act provide the following:

Limitation of Claims by applicant

(2) Where an application (the “original application”) describes more than one invention, the applicant may limit the claims to one invention only, and any other invention disclosed may be made the subject of a divisional application, if the divisional application is filed before the issue of a patent on the original application.

Limitation of Claims on direction of Commissioner

(2.1) Where an application (the “original application”) describes and claims more than one invention, the applicant shall, on the direction of the Commissioner, limit the claims to one invention only, and any other invention disclosed may be made the subject of a divisional application, if the divisional application is filed before the issue of a patent on the original application.

Prior to this, it was generally accepted that a forced divisional was any divisional application filed in response to a unity of invention objection raised during prosecution of the parent application. In fact, this continued after the introduction of subsection 36(2.1), under which a unity of invention objection was considered to be a direction from the Commissioner.

Prohibition against double patenting

Double patenting is prohibited in Canada to prevent more than one patent being issued for the same invention or obvious variations of the same invention. In other words, a patentee is prohibited from obtaining more than one patent that claims subject matter that is “conterminous” with, or obvious over, the claims granted in the first patent.

Distinguishing between voluntary and forced divisionals

It is not always clear when a divisional application is voluntary or forced. In NCS Multistage Inc. v. Kobold Corporation, 2023 FC 1486, Justice McVeigh explains that “a forced divisional patent arises where the Patent Office directs the inventor to divide, whereas an inventor who freely divides the surplus invention creates a voluntary divisional”. Nevertheless, there are diverging approaches as to what type of direction from the Patent Office would constitute a forced or voluntary divisional.

Unity of invention objection:

The first approach follows Consolboard and provides that a divisional patent will be considered forced if the applicant demonstrates the patent examiner made a unity of invention objection. Where a patentee followed the directions of the Commissioner, it would be unfair and inequitable to invalidate a patent.

Objection by way of final action:

On the other hand, a second approach suggests that a divisional application would be considered forced where it was made in response to a final action, rather than to an objection in the prosecution process. As such, a divisional application was not forced if the unity of invention objection did not constitute a rejection by way of a final action. Instead, an applicant would have to show something more than a mere unity of invention objection to conclude the divisional application was forced. This view also posits that an applicant who believed the objection was not merited could also choose to appeal the objection. Accordingly, such a divisional application would be considered “voluntary”.

An informed middle ground:

In the more recent decision of NCS, Justice McVeigh concluded in obiter that the preferred approach to determine whether a divisional application was forced was an informed middle ground between the two approaches. As Justice McVeigh explained, a divisional application will be considered forced and protected from double patenting attacks where “an inventor can trace the origin of the divisional back to a direction of the Commissioner”, and “voluntary” where the divisional at its core disclosed a different invention.

While the Court found ‎that the mere existence of requisitions in the patent file history was insufficient to demonstrate a forced ‎divisional, it did not clearly state what constituted a direction of the Commissioner in order for a divisional to be considered forced. While the Court likely borrowed the language from current subsection 36(2.1), this was an unfortunate choice of words as the Commissioner typically does not direct an applicant to file a divisional application in practice.

Protection from double patenting

Thus, conflicting approaches in the jurisprudence continue to make it uncertain as to what constitutes a forced divisional application. It is not likely that prosecution practice will change significantly in view of the recent decisions—examiners will not issue double patenting objections when claims are divided in response to a previous unity of invention objection. However, in view of the "middle ground” approach described in NCS and to shield claims from future litigation, it may be prudent to obtain a direction from the Commissioner prior to filing a divisional application. Although an examiner’s objection during prosecution is not generally considered to be a direction from the Commissioner, the Manual of Patent Office Practice (MOPOP) provides a mechanism to receive such a direction.

Under section 21.07 of the MOPOP, an applicant notified of a lack of unity defect by the examiner is requisitioned to correct it or to submit arguments as to why the claims do, in fact, comply with section 36 of the Patent Act. In response, the applicant has a one-time right to elect which invention will be the subject of examination in the application. Thereafter, any other invention disclosed may be made the subject of a divisional application. If the applicant declines to limit their claims to a single invention, the examiner may refer the application to the Commissioner for a determination of the issue. Typically, such a referral will not occur until the examiner has advised the applicant of the defect in at least two reports. However, the examiner must first submit the application to the Unity Review Board (URB) for review. The URB reviews the application to ensure the lack of unity defect was correctly identified and clearly articulated to the applicant such that the applicant was in a position to successfully respond to the examiner’s requisition. If the URB finds that a lack of unity of invention exists and the defect was clearly communicated, the application will be forwarded to the Commissioner for consideration.

Where the Commissioner has reason to believe that the application, upon review, does not comply with section 36, the Commissioner will send a Notice of Direction to the applicant to limit the claims to one invention only. This direction will be made under the authority of subsection 36(2.1). If the applicant’s amendments in response to the Notice fail to satisfy that the application complies with section 36, the application will be forwarded to the Patent Appeal Board for a final review. At this stage, the process resembles the review of a Final Action, given that the Patent Appeal Board may recommend that the Commissioner refuse the application.

It is appreciated that the process to obtain a direction from the Commissioner is not always practical. As such, it may suffice to have an examiner explicitly mention subsection 36(2.1) on record.