Sufficiency of Patent Disclosure Rests on Bargain Rather Than Guessing


Gambling by Alan Cleaver licensed under CC BY 2.0


The patent system is based on a “bargain” between the inventor and the public: the inventor receives exclusive rights in his or her new and useful invention for a limited period in exchange for complete disclosure of the invention to the public.


Consistent with this policy rationale, the inventor is required to disclose everything that is essential for the invention to function properly. In particular, the patent disclosure must define the nature of the invention, and must describe how the invention is put into operation. A failure to meet the first condition would invalidate the patent application for ambiguity, while a failure to meet the second condition would invalidate it for insufficiency.


To meet the sufficiency requirements, the patent disclosure must correctly and fully answer each of the two questions: (1) “What is your invention?” and (2) “How does it work?”


Further, the disclosure must enable a person skilled in the field of the invention to produce the invention using only the instructions contained in the disclosure and to make the same successful use of the invention as the inventor did. In essence, insufficiency is a technical attack on the validity of a patent, and would succeed when the skilled person could not put the invention into practice. For example, obscuring the true invention and leaving the skilled reader guessing may amount to insufficient disclosure.


Thus, as noted by the Supreme Court of Canada, a key question would be:


“Is the public getting what it ought to be getting in exchange for exclusive monopoly rights?”


As one would expect, insufficient patent disclosure that fails to uphold the inventor’s end of the bargain will result in a voidable patent.



Simple ≠ Obvious, Just Ask The Person Skilled In The Art

Simple ≠ Obvious - just ask the person skilled in the art

Simple & Obvious by
Emma Jane Hogbin Westby
licensed under CC BY 2.0


A new and useful invention is patentable only if it is not obvious to an unimaginative person of ordinary skill in the field of the invention. Obviousness assessment is based on the “state of the art” and the common general knowledge of the skilled person at the claim date of the invention.


At the core of obviousness analysis is the identification of the “inventive concept” of the claimed invention, and whether the difference between the inventive concept and the state of the art would require the skilled person to take any inventive step or conduct arduous searching and testing.


The obviousness analysis may involve consideration of a number of factors, including:

  • The interpretation of patent claim at issue.
  • The hypothetical skilled person and the common knowledge of this person.
  • The prior art and the climate or trends in the relevant field.
  • Any motivation at relevant time to combine or modify prior art to arrive at the claimed invention.
  • The time and effort involved in the claimed invention.
  • Whether the claimed invention was obvious to try.
  • Commercial success of the claimed invention.


The Canadian Federal Court of Appeal has cautioned against relying on hindsight when challenging a patent for obviousness:


Every invention is obvious after it has been made, and to no one more so than an expert in the field. Where the expert has been hired for the purpose of testifying, his infallible hindsight is even more suspect. It is so easy, once the teaching of a patent is known, to say, “I could have done that”; before the assertion can be given any weight, one must have a satisfactory answer to the question, “Why didn’t you?”


Even if an invention is directed to a particular combination of well-known parts, the combination itself is not necessarily obvious. In addition, the simplicity and easiness of an invention does not render it obvious. After all, a mere scintilla of invention is sufficient to support the validity of a patent.



Anticipation: The Precise Destination Has Been Occupied


The angler by Riccardo Palazzani licensed under CC BY 2.0


To be patentable, an invention claimed in a Canadian patent application must be new. Being “new” requires that the invention must not have been made available to the public, in Canada or elsewhere, in an enabling manner by a single prior disclosure. Such a prior disclosure, if found, is said to have anticipated the invention, and can be used to invalidate the patent issued for the invention.


Generally, anticipation is assessed based on what was known prior to the claim date of the invention. The claim date is either the filing date of the Canadian application, or the filing date of an earlier application disclosing the same invention. As an exception in Canada, any inventor-originated disclosure of the invention occurred within one year before the Canadian filing date cannot be cited against the claimed invention.


A prior disclosure can be a patent document, a publication, a known product, a communication of information, or the inventor’s prior public use or sale of the invention. It is worth noting that a third party’s Canadian patent application having an earlier claim date than the claimed invention may be citable against the claimed invention for anticipation, regardless of the publication date of the third party application.


A disclosure would be considered as made to the public if at least one member of the public had an opportunity to access the information that is the invention without any restriction to the use of the disclosed information.


To establish anticipation, a single prior disclosure must include all essential elements of the claimed invention, and must provide sufficient information so that a person skilled in the field of the invention can perform the invention without undue effort.


Anticipation can be difficult to establish. In the words approved by the Supreme Court of Canada:


A signpost, however clear, upon the road to the patentee’s invention will not suffice.  The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee.


To avoid losing patent rights, the most prudent practice for the inventor is to never publicly disclose the details of his or her invention before filing a patent application for the invention.



Do Not Make Broken Promise In Patent Applications


Auto wreck, USA, 1923 by National Photo Company via Wikimedia Commons.


In Canada, a patentable invention must be useful, or have utility. Otherwise the patent issued for the invention is invalid.


A patented invention lacks utility if it will not operate at all, or if it will not do what was promised in the patent.


Where a patent does not promise any benefit of the invention, the utility requirement can be easy to meet. For example, it is generally sufficient if the invention provides any industrial or commercial value, or affords the public a useful choice.


However, if a patent promises a specific effect of the invention, then the utility of the invention will be measured against the explicit promise. This means that a patent may be invalidated for containing unsupported statements to the superiority or uniqueness of the claimed invention.


The patent owner must be in a position to establish utility as of the Canadian filing date of the patent. Utility can be established as demonstrated utility showing that the invention in fact works, or on the basis of a “sound prediction” that the invention will likely work. There is no requirement to prove utility in the patent itself. However, if the utility is based on sound prediction, the patent must include:

  1. a factual basis for the prediction;
  2. a sound line of reasoning from which the desired result can be inferred from the factual basis; and
  3. proper disclosure to support the prediction.


Making promises in a patent may create uncertainty in the validity of the patent. Therefore, patent applications should be drafted with no broken promise, or no promise at all.