Best Mode in Canada

Best Mode in Canada
Stuart Bristowe, Ph.D. September 1st, 2012

In the United States according to 35 U.S.C. 112 “the specification….shall set forth the best mode contemplated by the inventor of carrying out his invention.”  As is readily apparent from this language, this best mode requirement for U.S. patent applications is relevant to all technologies.

In Canada, according to Section 80(1)(f) of the Patent Rules, the description shall set forth at least one mode contemplated by the inventor for carrying out the invention in terms of examples.  Furthermore, there is a best mode requirement specifically defined in the Patent Act, however it is not as definitive as that of the United States.  In Canada, Section 27 (3) of the Patent Act defines the requirements of the specification for a patent application.  This section outlines the necessary requirements of the specification which include for example, correctly and fully describing the invention, setting out clearly the various steps in a process, method of constructing making or using a machine manufacture or composition of matter.  However, when outlining the requirement of best mode, this section of the Patent Act solely limits the best mode requirement to a machine.  Specifically, Section 27(3)(c) defines that the specification of an invention must “in the case of a machine, explain the principle of the machine and the best mode in which the inventor has contemplated the application of that principle”.

It is important to note that the requirement of disclosing the best mode in a specification has essentially been extended to all technologies and not just limited to a machine type invention, based the outcome of the Federal Court Trial Division decision regarding Thomas & Betts Ltd v. Panduit Corp. (1997).  The Court determined that the inventor has a duty with the fullest of bona fides to describe the best way known to them of carrying out the invention.

When determining what to integrate into a patent application in terms of describing the best mode, it is important to consider the relevant date with respect to testing for the best mode.  In the past, this relevant date had been determined to be the filing date of the patent application or the Paris Convention priority date, if this is deemed relevant to the particular case.  However, in 2000 the Supreme Court of Canada established the relevant date in two separate decisions, namely Free World Trust and Whirlpool.  The SCC firmly established that the relevant date is the date when the public first became aware of the patent application, which is typically 18 months after filing.

It is apparent that this revision to the relevant date for determining the best mode may cause some potential issues when one considers the language of Section 27(3)(c) of the Patent Act, wherein it is defined the requirement relates to the best mode in which the inventor has contemplated the application of the principle of the machine.

As is known, no new subject matter can be added after the filing date of the application.  Rather, all amendments must be fully supported by the application as originally filed.  As such there is a potential incongruence regarding the disclosure requirement of the best mode, particularly if the best mode has been “contemplated” by the inventor after filing of the application but before its publication.

As such, when preparing a patent application for an inventor, it can be advisable to ask the inventor to speculate as to potential improvements to their technology, and to integrate these potential improvements into the application, assuming that these potential improvements have a reasonable probability of success.  In this manner, should it be later established that at the time of publication the best mode includes one or more of these potential improvements, it can be argued that the best mode has been appropriately disclosed in the patent application in question.

For more information please contact Stuart Bristowe