New Canadian Examination Guidelines: Claim Construction and Computer-related Subject Matter

Mar 21 2013

On March 8, 2013, the Canadian Patent Office released new examination guidelines to account for the Federal Court of Appeal decision in Canada (Attorney General) v Amazon.com Inc., 2011 FCA 328 (Amazon FCA Decision).

The guidelines relate to the purposive construction of claims (Exam Memo PN2013-02) and the examination of computer-implemented inventions (Exam Memo PN2013-03).

Examination Practice Respecting Purposive Construction

An examiner must interpret each claim:

  • Using a fair, balanced and informed approach

The claims should be read by the examiner purposively, in consideration of the specification as a whole as read through the eyes of the person of skill in the art, and the common general knowledge of that person at the time the application became available to the public. The guidelines acknowledge that the necessary foundation of knowledge for performing a purposive construction is found in submissions from the applicant and knowledge of an appropriately experienced examiner.

  • Having identified the problem and solution

The problem and the solution proposed by the inventor(s) to address the problem are to be identified in the description (paragraph 80(1)(d) of the Patent Rules) and not by reference to the closest prior art. This determination is made when construing the utility, or promise, of the invention, and as such it informs the purposive construction of the claims.

  • In the context of the application as a whole

Although claim construction is anchored in the language of the claims, a solely literal reading of the claims is not appropriate. To carry out a purposive construction of the claims, the application as a whole must be considered. This assessment is done in light of the description, the common general knowledge in the relevant art and the examiner’s technical expertise. Consideration may be given to what the inventor actually invented versus what the inventor claims to have invented to avoid the “pitfalls of language” in claim wording. This ensures that protection is only available to the inventor for that which he actually, in good faith, invented.

  • To determine which elements of the claim solve the identified problem

In purposively construing the claim, the essential elements of the claim must be identified. Identifying the problem and the proposed solution, as noted above, is a necessary precursor to this analysis as what is determined here is what element(s) is/are essential to the operation of the solution.

The determination of what elements are essential is performed in view of the knowledge of the art at the date of publication of the specification.  One or more essential elements may contribute to the “inventive solution”.

The following is a list of what is not or may not be essential:

  • An element is non-essential if the skilled addressee would appreciate that a particular element could be substituted without affecting the working of the invention.
  • Having a material effect on the operation of a given embodiment does not necessarily mean that the element is essential to the operation of the invention. The element may simply define the context or environment of a working embodiment while not changing the nature of the solution to the problem.
  • One cannot simply conclude that the essential elements of the invention are those that distinguish the claimed subject matter from the prior art.

A claim lacking an element essential to the operation of the solution may be defective for overbreadth or lack of proper support or utility.  Conversely, an element that is superfluous (non-essential) to the solution, while having no bearing on patentability (unless it introduces ambiguity), may create problems if included in the issued version of the patent: if a court later construes the element to be essential, this may allow a potential infringer to avoid a finding of infringement and as such, the inclusion of the element in the claim may serve as a “self-inflicted wound”.

  • By focusing on one solution to a problem

If a claim includes solutions to more than one problem, it includes more than one invention. When this is the case, the purposive construction undertaken during examination will focus on one solution only: that which is given the greatest emphasis in the description.

If a claim includes elements that do not interact to achieve a unitary result, and as such reflect a mere aggregation rather than a combination, the examiner may consider the problem and solution emphasized in the description to select only the elements that work together in the claim to provide the operable solution.

Once the claims are purposively construed, it is then that the examiner can determine whether or not the subject matter defined by the claims comply with the Patent Act by being a new, useful and inventive art, process, machine, manufacture, composition of matter, or improvement thereof.

Examination Practice Respecting Computer-Implemented Inventions

It is still the case that a computer-implemented invention may be claimed as:

It also remains true that the following computer-related subject matter may not be claimed:

  • computer programs per se;
  • data structures; and
  • computer-generated signals.

However, in view of the Amazon FCA Decision, the evaluation of the subject-matter of a claim for compliance with section 2 of the Patent Act is to be made on the basis of the essential elements as determined through a purposive construction. This assessment is accomplished by identifying the problem the inventors set out to solve and the proposed solution, having regard to the specification as a whole. It is important to note that the Patent Office is now mandated to use a purposive construction in place of other approaches to claim analysis. As such, the “contribution approach” previously adopted by the Patent Office is no longer in use.

  1. Identifying the Problem

The problem need not be explicitly identified as such, per paragraph 80(1)(d) of the Patent Rules. The identification of the problem is guided by the common general knowledge in the art and the description. Emphasis on certain aspects of the solution may help to identify the problem, while less emphasis on aspects of the solution may suggest that the problem lay elsewhere. Where there is an explicit statement of the problem, examination will proceed accordingly unless it is unreasonable to do so in view of the common general knowledge.

Also informing the identification of the problem are statements in the description about

  • the background of the invention,
  • objects of the invention (objectives),
  • specific problems, needs, limitations, or disadvantages known in the art, etc.

The problem may be a “computer problem” (i.e. a problem with the operation of a computer) or it may not be a “computer problem”, but instead, a problem whose solution may be implemented using a computer.

  1.  Identifying the Solution

The solution is the element(s) essential to the successful resolution of the problem. Again, this assessment is based on an analysis of the specification as a whole and the common general knowledge.

If the problem is a “computer problem”, the elements of the solution are those that address problems relating to the operation of the computer.

However, if the problem is not a “computer problem”, it must be determined if the computer is actually an essential element of the solution, or merely a convenience or afterthought, as would be the case where the solution lay in performing certain calculations according to an equation, and a computer is used simply to perform those calculations expediently without having any material effect on the operation of the equation (e.g., where the calculations could also be performed using pen and paper). Conversely, the computer element would be considered an essential element of the claim where

  • the computer element cannot be varied or substituted without making a difference in the way the invention works; or
  • the computer is required to resolve a practical problem.

Where the computer is determined to be an essential element, the claimed subject-matter will generally be statutory.


Generally, the Patent Office will assess whether claimed subject matter is an “invention” in accordance with section 2 of the Patent Act (i.e. “statutory subject matter”) based on the essential elements of the claim as determined by a purposive construction of the claim. The contribution approach to claim analysis, previously used by the Patent Office, is now supplanted by the purposive approach, which takes into consideration the specification as a whole, as read through the eyes of the person of skill in the art and that person’s common general knowledge as of the date of publication of the specification. An assessment of a patent’s scope of protection based on a literal reading of the claims is therefore no longer appropriate. Instead, the contents of the description, and in particular, the problem and solution described, will inform the meaning of terms used within the claims and the actual invention to be protected, as distinguished from the invention claimed as determined by an analysis of claim language alone.

This article is for information purposes only and does not constitute legal or professional advice.

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Tags: Claim Construction, Patents