This is part of a series of posts reviewing common Canadian Patent Office objections to patent applications and claimed inventions and providing some insight into how these objections may be addressed.
Equivalents clauses are common in patent specifications, particularly those originally prepared and filed in the United States. A classic equivalents clause provides that the invention is not limited to specific embodiments disclosed in the description, and encompasses modifications falling within the scope of the claims. In the US, the clause reinforces application of the doctrine of equivalents. In Canada, the clause has a similar function, reinforcing a purposive construction of the claims.
In a standard objection, the patent examiner asserts that the description does not comply with subs. 27(3) of the Patent Act because the equivalents clause: (a) does not correctly describe the invention, and (b) attempts to broaden the scope of the claims. Typically, the examiner requests deletion of the clause from the application. The Canadian Manual of Patent Office Practice has apparently included an objection to the equivalents clause for some time; however, patent examiners have only recently started to raise this objection with any frequency.
The Statutory Provision
The Patent Act provides a statutory framework for balancing the rights of the public and patent applicants. An applicant is granted patent claims under subs. 27(4) of the Act in return for an enabling description of the claimed invention under subs. 27(3). A bargain is struck between the patentee’s right to exclude others from practising the claimed invention and the public’s right to a proper disclosure that explains how to practice the invention and shows that the inventor was in possession of the invention at the time of filing.
Objections to equivalents clauses often purport to be grounded in para. 27(3)(a) of the Act, which states:
27 (3) The specification of an invention must:
(a) correctly and fully describe the invention and its operation or use as contemplated by the inventor….
The disclosure requirement in para. 27(3)(a) is similar to the written description requirement for US applications in 35 U.S.C. §112, 1st para.
Addressing the Objection
Here are some reasons why you should consider arguing in traverse of a subs. 27(3) objection to an equivalents clause:
- Subs. 27(3) of the Patent Act is a provision of inclusion, not exclusion: it sets out the information that must be included in the application, but does not mention any information that must be excluded. This provision does not provide a basis in law for requiring deletion of material included in the application as filed.
- Any attempt to amend or delete content of the description inherently exposes the application to a new-matter objection.
- Unlike Europe, Canada does not require that the description be amended to conform to the claims ultimately allowed. Such an amendment should never be necessary in Canada if the claims are properly supported by the disclosure as filed.
- Since a court purposively construing the claims may look to the disclosure to assess the meaning of claim language, a patent applicant should be loath to delete any content from the specification as filed.
- The invention for which patent protection is sought is defined by the claims, not the disclosure. For each invention defined by a claim, subs. 27(3) requires that proper support be provided in the description. The objection to the equivalents clause is backwards. It suggests that the description (content fixed as of the filing date) is being used to broaden the invention defined by the claims (which can be amended while the application is pending.)
- If a claimed invention is described somewhere in the application as filed, the descriptive support requirement of subs. 27(3) has been satisfied. The presence of an equivalents clause does not impact this assessment unless the only basis for a claim resides in the clause itself.
- In that case, the objection should be directed to the claimed invention, not the description, on the basis that it lacks descriptive support under subs. 27(3).
Next up: Responding to an objection to the claims under s. 84 of the Patent Rules on the basis that they are broader in scope than the teachings of the description.