Public disclosures of inventions – what you need to know about Canada’s grace period
October 28, 2013

by Sanro Zlobec

Changes in U.S. law introduced by the America Invents Act (AIA) have shone the light on the issue of public disclosures of inventions for patent applicants filing in Canada. While Canada allows an applicant to file a patent application within one year from the invention’s first public disclosure, the effect of such a public disclosure may now be quite different than in the United States. As such, applicants with the intention of filing in Canada should be aware of certain acts that may be more harmful to their Canadian rights than they might expect. Fortunately, the impact of these situations can be minimized with appropriate internal management practices.

Applicants filing in European or Asian countries would typically not consider it prudent to disclose an invention before filing a patent application, as their patent rights could be jeopardized. Even unintentional early disclosure will cause an irreparable loss of rights in many jurisdictions. However, Canada is in a group of countries that are more permissive in this regard. Thus, if early disclosure of an invention takes place — be it by design or accidentally — it may still be possible to obtain patent rights in Canada and certain other economically significant regions of the world.

Recently, changes in patent law in the United States under the AIA have altered the patent landscape significantly, including the provisions dealing with public disclosures prior to filing. While the effect of many changes remains to be seen, it appears that under some of these new provisions, an applicant's own disclosure may, under certain circumstances, act as a “shield” against intervening third-party disclosures, if a patent application is filed somewhere in the world within one year of that original disclosure.

However, the situation is considerably different in Canada, where an applicant that has disclosed its invention must not only be the first to file a patent application, but must also ensure that the Canadian patent application is on file within one year of the first public disclosure.

Specifically, applicants who render their inventions available to the public anywhere in the world have one year within which to obtain a Canadian filing date. This can be achieved by filing a Canadian patent application or a Patent Cooperation Treaty (PCT) application at any PCT receiving office. However, third-party disclosures of the invention that precede the Canadian filing date (or the priority date, if applicable) are fatally damaging to the Canadian application. That is, unless it is by “a person who obtained knowledge, directly or indirectly, from the applicant,” a public disclosure that occurs before the Canadian filing date (or the priority date, if applicable) is citable against the Canadian application, even if this disclosure occurs subsequent to an earlier disclosure by the applicant.

Thus, from the perspective of obtaining a valid Canadian patent, public disclosure of an invention prior to filing the Canadian patent application would seldom be considered beneficial, and, at best, can be neutralized if prompt action is taken. That is, to preserve Canadian patent rights should an invention be disclosed to the public anywhere in the world, a priority application should be filed as soon as possible. If this priority application is non-Canadian or non-PCT, a Canadian patent application must be filed within one year of the public disclosure. Unlike what may be the case elsewhere, the filing of the priority application is not sufficient to avoid the disclosure bar in Canada.

Practically speaking, therefore, applicants that intend to file in Canada and are faced with a premature public disclosure should file a priority application promptly following the disclosure and ensure that the Canadian (or PCT) application is filed within twelve months of the disclosure in order to preserve their Canadian patent rights.

If you have any questions regarding the above, please do not hesitate to contact a member of our firm’s Patents group.


The preceding is intended as a timely update on Canadian intellectual property and technology law. The content is informational only and does not constitute legal or professional advice. To obtain such advice, please communicate with our offices directly.

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