Much can happen after a patent is issued. Laws change, industrial processes improve, competitors emerge, and new products and features are in demand. Consequently, a patent portfolio should be periodically assessed to ensure it fully protects the exclusivity of an invention and provides a competitive advantage to the patentee as the market landscape evolves. The assessment should be made against marketed products and production processes — the patentee's as well as competitors'— to ensure the portfolio remains relevant and robust.
Following such an assessment, certain key patents in the portfolio may be identified as problematic or inadequate and amendments to them may be required.
A patentee's ability to amend an issued patent in Canada is limited. Nevertheless, there are four avenues available:
- Correcting clerical errors;
- Disclaimer;
- Reissue; and
- Re-examination.
Availability and Limitations
Errors in a specification that arose from the process of writing, transcribing or reproducing text may be corrected at any time during the term of a patent. Significant amendments may be made if a clerical error is established. However, correction is discretionary, and may be refused by the Commissioner of Patents if contrary to public interest. Thus, replacement of whole claims, corrections of translation errors or priority claims, or amendments to broaden the scope of a claim are unlikely to be allowed.
A disclaimer can be used to disclaim claims or parts thereof, thereby enabling the patentee to reduce claim scope. Claimed subject matter can be disclaimed if it was originally included by mistake, accident or inadvertence and without any wilful intent to defraud or mislead the public. Disclaimers may be made at any time over the term of the patent and are typically used to exclude specific features in a claim that are anticipated by prior art or are inoperative.
Disclaimers are not reviewed by the Patent Office and cannot be refused. As a result, care should be exercised when preparing disclaimers to ensure that claim scope is not inadvertently broadened. Otherwise, the resulting claims may be held invalid during a future impeachment proceeding.
A defective or inoperative patent may be corrected by reissue if requested within four years of its date of issue. The defect must be by reason of insufficient description or specification, or a patentee claiming more or less than they had the right to claim. The error resulting in the defective patent must have arisen from inadvertence, accident or mistake and without any fraudulent or deceptive intention. Errors of omission, miscommunication, misunderstanding of foreign practice or misappreciation of information may be addressed, provided the subject matter was intended to be protected in the original patent.
Reissue facilitates amendments that redefine the originally-claimed invention by, for example, broadening or narrowing the scope of issued independent claims or adding new narrower claims, and allows amendments to the patent description to add subject matter that is common knowledge. However, amendments to add new matter, to reintroduce claims cancelled during prosecution, or to take advantage of a new law or jurisprudence are not permitted. If a request for reissue is accepted, an amended patent specification is subject to further examination.
Re-examination provides a means to amend patent claims whose patentability is in doubt in view of prior art. Newly discovered prior art or art that was misappreciated during examination may be raised. Where a substantial new question of patentability is raised, a re-examination board considers the patent claims in view of supplied prior art. A patentee can propose non-broadening amendments to the patent claims. Following re-examination, the board may cancel non patentable claims, confirm claims, or incorporate amended claims. The board's decision is subject to appeal by the patentee. Interestingly, re-examination may also be used by a third party to summarily challenge the patentability of issued claims on the basis of prior art.
There are different procedures, requirements and limitations associated with each of the above avenues and varying degrees of amendment are possible. Careful consideration must be undertaken in order to select the appropriate route and to navigate through it successfully.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
