Divisional patent applications play a crucial role in patent portfolios, particularly when an initial patent application describes multiple closely related inventions. The Canadian Intellectual Property Office (CIPO) allows for the separation of these inventions into divisional applications, but the Canadian patent system is much less permissive than other countries. Unlike in the United States, where a terminal disclaimer can be filed to overcome double patenting rejections, Canada does not offer this option, making the strategic filing of divisional applications more complex.
Double Patenting
Double patenting is a significant concern in Canadian patent practice, especially for divisional applications. The concept of double patenting in Canada prevents the issuance of multiple patents for the same invention or for inventions that are not patentably distinct from one another. This restriction particularly impacts divisional applications, which may face rejection by the patent office or invalidation by a court for claiming an invention that is identical or conterminous with, or obvious in view of, the claims of the parent application.
In Canada, unlike in the United States, terminal disclaimers cannot be used to overcome double patenting rejections. This limitation means that careful planning is required when filing divisional applications to avoid potential pitfalls associated with double patenting.
Exemption for Unity Rejections
Fortunately, there is a significant exemption to the double patenting rule in Canada for divisional applications filed in response to a unity rejection. If CIPO issues a unity rejection, alleging that the application contains multiple inventions, the applicant can safely file a divisional application for one or more inventions identified by the patent examiner.[1] However, voluntary divisional applications—those not filed in response to a unity rejection—remain vulnerable to double patenting. Therefore, to strategically file a divisional application, it may be necessary to provoke a unity rejection by adding claims directed to a second invention.
Cost Considerations
In the past, it was common for applicants to file any number of claims in a single application—sometimes more than 100 claims—which would be subsequently filed in divisional applications in response to a unity rejection. However, Canada recently introduced excess claim fees which has forced patentees to reconsider their Canadian filing strategies. The standard fee for each excess claim over 20 is currently $110 ($55 for small entities)[2] and is based on the greatest number of claims pending in the application at any time after requesting examination. Fortunately, Canada permits multiple claim dependencies, which can be employed to limit the total number of claims while protecting the many features of an invention.
When provoking a unity rejection, it is advisable to consider the number of claims carefully. Furthermore, additional claims should be added prior to allowance. After CIPO issues a notice of allowance, amending the claims requires a request for continued examination, which incurs an additional government fee ($1,100, or $450 for a small entity)[3].
Practical Tips and Best Practices
For those navigating the complexities of Canadian divisional patent practice, the following tips may be helpful:
- File Divisional Applications Only in Response to a Unity Rejection: This approach minimizes the risk of double patenting rejections and invalidation of the granted patent, as divisional applications filed in response to unity rejections are generally shielded from such concerns.
- Align Divisional Claims with Unity Rejection: To avoid double patenting allegations, ensure that claims filed in the divisional application closely reflect the unelected claims in the parent application.
- Manage Claim Counts Carefully: Given the recent introduction of excess claim fees, it is essential to carefully manage the number of claims in both the parent and divisional applications to avoid unnecessary costs.
Conclusion
The introduction of excess claim fees in Canada has added a new layer of complexity to the strategic filing of divisional applications, which already required careful navigation due to stringent double patenting rules. As long as claim fees discourage the previous practice of freely adding multiple inventions to a single application, the risk associated with voluntary divisionals remains a significant challenge. Until Canadian legislators re-evaluate these conflicting rules, careful planning and expert guidance are essential for successfully managing divisional applications in Canada.
At PCK, we are equipped to help innovators navigate these complexities and ensure that their inventions are protected to the fullest extent possible under Canadian law. For further guidance, please contact Gillian Burrell at info@pckip.com.
Footnotes
[1] Patent Act, subsections 36(2) and 36(2.1).
[2] https://ised-isde.canada.ca/site/canadian-intellectual-property-office/en/patents/patent-fees
[3] https://ised-isde.canada.ca/site/canadian-intellectual-property-office/en/patents/patent-fees
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The contents of this article are provided for general information purposes only and do not constitute legal or other professional advice of any kind.