No Mosaicing of Obscure Prior Art

dTechs EPM Ltd v British Columbia Hydro and Power Authority 2021 FC 190 Fothergill J

2,549,087 / Electrical Theft Detection System

I had intended to return from my blogging break with a post on the “inventive concept” aspects of Apotex v Shire 2021 FCA 52. That is turning into a bigger project than anticipated. I’ll have a few posts on that issue in another week or two. In the meantime I’ll catch up on the decisions that came out while I was on break, starting with dTechs.

In this decision Fothergill J held dTechs’ 087 patent to be not infringed, and also invalid for anticipation and obviousness. The decision turned almost entirely on claim construction and the facts. There were two legal points of interest, though the decision did not turn on either of them. First, Fothergill J held one of the claim elements to be non-essential. This is not unheard of, but unusual enough to be noteworthy. Of more general interest going forward, while Hospira 2020 FCA 30 held that obscure prior art is now part of the state of the art for the purposes of an obviousness attack, Fothergill J understood it as holding, or at least suggesting, that mosaicing of obscure prior art is not permitted.

The 087 patent relates to a system for detecting the theft of electrical power, such as by illegal marijuana grow-ops. The system works by monitoring the current power consumption at a primary line, that serves a number of downstream transformers, and comparing it to “known consumption patterns” to detect atypical power consumption patterns that might indicate power theft. The inventor and founder of dTechs was a former police officer who had become interested in the identification of marijuana grow operations by tracing the electricity theft during his investigations into organized crime and illegal drugs. He eventually quit the force to set up dTechs and commercialize his invention. The defendants were Awesense, which provided a similar system to BC Hydro, and BC Hydro itself. As usual, the defendants argued non-infringement and invalidity.

Infringement turned entirely on claim construction. Fothergill J adopted a construction of the term “known consumption patterns” that favoured the defendants [153], and non-infringement followed directly [174]. The main point of interest on claim construction was that Fothergill J held a different term, “notifying the utility” to be non-essential, applying the Free World 2000 SCC 66 test for essentiality [154–61]. This is noteworthy because it is quite unusual for a claim term to be held to be non-essential. However, this holding did not make any difference to the result, which turned entirely on the construction of “known consumption patterns.”

In a second point of interest, Fothergill J noted at [248] that in Hospira 2020 FCA 30 [86] the FCA held that all prior art should be considered part of the state of the art for the purpose of an obviousness attack, and not just prior art that would have been discoverable on a reasonably diligent search: see here. It’s convenient to refer to prior art that would have been discoverable on a reasonably diligent search as ‘obscure prior art.’ However, in Hospira “the Federal Court of Appeal acknowledged that the discoverability of a prior art reference may be relevant to the fourth step of the obviousness analysis” [249], in the following passage:

[86] The likelihood that a prior art reference would not have been located by a PSA may be relevant to consideration of step 4 of the obviousness analysis (whether differences between the state of the art and the inventive concept constitute steps which would have been obvious to the PSA) in that the uninventive PSA might not have thought to combine that prior art reference with other prior art to make the claimed invention.

In my post on Hospira I noted that “This indicates that there can be no mosaicing of prior art that is not available in a reasonably diligent search.” The point was made somewhat tentatively in Hospira, with the FCA saying that the fact that the prior art is obscure “may” be relevant and that the skilled person “might” not have thought to combine the obscure prior art references. It was not entirely clear whether the FCA was stating a rule of law that mosaicing of obscure prior art is not permitted, or merely suggesting that that would be an issue to be considered on the facts. The “may” and “might” language suggests it is a factual issue, but if so, it is a very hypothetical matter of fact, given that in fact, the skilled person would not have found the obscure prior art as well. It’s a bit convoluted to say that there is a factual issue as to whether the skilled person would have thought to combine two pieces of prior art which she would not in fact have been aware of.

In any event, Fothergill J remarked that “[250] Even if the PSA lacks the ingenuity to combine more than one prior art reference to achieve the claimed invention” the claimed invention would nonetheless be obvious. So, he did apparently understand Hospira to be saying that mosaicing of obscure prior art is not permitted, though his holding that the 087 patent was obvious did not turn on the point.

Fothergill J also held that certain of the asserted claims were anticipated by BC Hydro’s prior practices. While those practices did not reflect the preferred embodiment of the invention, Fothergill J held on the facts that the prior practice would have necessarily infringed and so satisfied the test for anticipation [183], [192], [204]. Most of the asserted claimed were also anticipated by a report prepared by the inventor himself during his time on the police force, which proposed a system that eventually matured into the invention. One key issue on this point was whether the disclosure of the report to the police force was subject to an expectation of confidence. Fothergill J held on the facts that it was not: [209–12], [218]. Most claims were also anticipated by a prior publication, again following on the claim construction holdings and the rule that that which infringes if after anticipates if earlier [219]–[235].