Pursuant to the Canadian Patent Act, three procedures are available to a patentee for amending the claims of a patent post-grant.
The first is a reissue, which applies where a patent is deemed defective or inoperative due to the patentee claiming more or less than they had a right to claim as new, and where the error arose from inadvertence, accident or mistake, without any fraudulent or deceptive intention. To apply for a reissue, a patentee must surrender the original patent and a new patent is granted after a substantive review of the reissue application by the Patent Office. An application for a reissue must be filed within four years of the date the patent was granted. The second is ex parte re-examination, which permits the claims to be narrowed but not broadened. Although re-examination can be requested at any time, the request will only be granted if a re-examination board is satisfied that a substantial new question of patentability has been raised.
The third available procedure is the filing of a disclaimer, which is applicable where a patent specification is too broad and claims more than what was invented. As with reissue, the error must have arisen as a result of mistake, accident or inadvertence and without any willful intent to defraud or mislead the public. Unlike a reissue, there is no deadline for filing a disclaimer. In addition, the Patent Office does not conduct a substantive review of the disclaimer and, indeed, has no discretion to refuse one.
The recent judgment of Justice Martineau of the Federal Court in Hershkovitz v. Tyco Safety Products Canada Ltd., 2009 FC 256, has significant implications regarding the risks to Canadian patentees who utilize these post-grant procedures to amend a patent. The two patents at issue related to a telephone line coupler circuit and methods relating thereto. Shortly before commencing the action, the patentee filed disclaimers narrowing the scope of the claims by adding new limitations. The same limitations were added to the claims of the corresponding United States patent during a reissue that was filed almost three and a half years prior to the filing of the disclaimers in Canada. In defending the action, the defendant asserted that the patents at issue were invalid on the grounds of anticipation and obviousness and that the disclaimers filed by the patentee were also invalid.
In his decision, Justice Martineau concluded that the disclaimers were invalid on a number of grounds, including that:
- they were not in the prescribed form under the Patent Rules,
- they introduced a "new inventive idea," and
- they were not filed to correct a "mistake, accident or inadvertence."
Prescribed form. The form used when entering a disclaimer is set out in the Patent Rules. It requires a patentee to disclaim the entirety of the claim that is the subject of the disclaimer, either without qualification or with the inclusion of the language "with the exception of the following." The disclaimers filed by the patentee in this action followed the technical language of the form, and after the phrase "with the exception of the following," the patentee re-inserted the entirety of the original claim along with the new limitations.
The Court concluded that the patentee had not respected the requirements of the form of the Patent Rules and that the disclaimers were therefore invalid. The Court was of the view that the form required the patentee to state in a positive manner the portions of the original claim that were being disclaimed, rather than to re-introduce the original claim with further limitations. This is a curious result, as the disclaimer complied with the technical requirements of the form and provided clear notice of the portion of the claim that was not being disclaimed. Indeed, where a claim is being narrowed through the addition of a further limitation, in many instances, it is difficult to envision how a disclaimer could be entered other than in the manner used by the patentee.
"New inventive idea." Justice Martineau was of the view that the disclaimer procedure, which he referred to as a procedural rule for convenience, should be contrasted with the reissue procedure, whereby a defective patent can be surrendered and corrected. He concluded that a patentee cannot introduce a "new inventive idea" to the claims by way of a disclaimer as this is properly the subject of a reissue. In applying these principles, the Court determined that the disclaimers filed by the patentee added new subject matter to the claims resulting in new inventive combinations, which rendered the disclaimers invalid. The Court was influenced by the fact that the new limitations added by the disclaimer, although supported by the disclosure, were not included in the original claims. The Court also took into account evidence filed by the inventor regarding the inventiveness of the features added by the disclaimer.
Mistake, accident or inadvertence. When the validity of a disclaimer is challenged, the burden is on the patentee to prove there was a mistake, accident or inadvertence that made the claims too broad. In this case, the inventor was aware of the prior art that the disclaimer sought to overcome many years prior to filing the disclaimer. Indeed, one of the patents was still in prosecution when the corresponding United States reissue application was filed. In addition, at trial, the patentee could not specifically identify the "mistake, accident or inadvertence" that gave rise to the disclaimer, notwithstanding that the disclaimers had been filed on his behalf.
The Court held that patentees owe a duty of good faith to file a disclaimer promptly and diligently when they become aware of an inadvertence, accident or mistake. The Court concluded that the patentee filed the disclaimers as part of its litigation strategy rather than out of a need to diligently correct a bona fide mistake, accident or inadvertence. Accordingly, the disclaimers were held invalid on this additional basis.
Effect of invalid disclaimers. The Patent Act is silent on the consequences of filing an invalid disclaimer. Justice Martineau concluded that one should logically return to the original claims. However, upon filing a disclaimer, the patentee is required to state that the original patent specification is too broad and claims more than what was invented. Therefore, the Court concluded that a disclaimer is an act of renunciation of subject matter that serves as an admission by the patentee that the original claims were invalid and that, as a result, the original claims wear the defects confessed by the disclaimer "like a scarlet letter." Therefore, the Court held that the original claims of the patents at issue were themselves invalid in view of the admissions arising from the disclaimers.
Justice Martineau's decision has been appealed. Unless overturned or until the Patent Act is amended, significant care must be exercised before making any post-grant amendments to patent claims through a disclaimer. Overall, the decision stresses the importance of ensuring that the inventive elements disclosed in the patent specification are sufficiently covered by the claims during the prosecution of the application.
Our articles and newsletters are informational only, and do not constitute legal or professional advice. To obtain such advice, please communicate with our offices directly.