Smart & Biggar
On the 7th of June 2024, the Federal Court released its Judgment & Reasons in Tekna Plasma Systems Inc v AP&C Advanced Powders & Coatings Inc (2024 FC 871), which found all claims of Defendant’s Canadian Patent no 3,003,502 (502 Patent), and most claims from Canadian Patent no 3,051,236 (2336 Patent) invalid due to ambiguity. The court also declared Tekna Plasma Systems Inc. The Federal Court’s comprehensive decision emphasized the importance of predictability of the monopoly claimed by a patent for the public. The Federal Court’s comprehensive decision emphasized the importance for the public of the predictability of the monopoly claimed by a patent.
Tekna was successfully represented by Smart & Biggar litigators Francois Guay, Jeremy Want, Jean-Sebastien Dupont, Matthew Burt and Audrey Berteau.
Background
Tekna and AP&C Advanced Powders & Coating Inc (AP&C) both manufacture metal powders by plasma atomization, mainly for use in additive manufacturing. Plasma atomization, in its simplest form, is a technique that produces fine spheroidal powders of metal by contacting a wire with an atomizing liquid heated to plasma state. The metal melts, and is atomized to form small liquid droplets. As the liquid metal droplets rapidly cool, they solidify into micron-sized powder particles.
Tekna was successful in obtaining a declaration from the Federal Court that most of the claims of AP&C’s patents are invalid for ambiguity and a declaration that no claims of either the 502 and 236 patent had been infringed by Tekna’s production of titanium alloy powders. Only 14 out of 147 claims in AP&C’s 236 Patent have been found valid. Both patents are closely linked, as they both originate from the same parent application. Both patents relate to an atomization manufacturing method that claims to improve flowability of the powder particles. Both patents have a common element that is essential to their claims: the formation of an “depletion” layer at the surface of the reactive metal powder particles. The 502 patent claims and some of the 236 claims involve bringing a gas additive into contact with metal powder particles during atomization, which results in the formation on the surface of the metal powder particle. The claims of the 502 patent and some claims of the 236 patent claim the formation of two layers at the surface of the particles: a first depletion layer and a second oxide layer.
Key findings
Construing “depletion layer”, a term coined by the inventors
This decision centers around the meaning of the term “depletion layer.” As agreed by the parties and their experts, a “depletion layer” is not a term that is generally used in the field of powder manufacturing but is rather a term coined by the inventors of the patents. The meaning of the term had to be determined by reading and interpreting the patents in the same way as a skilled reader would. The Court stressed that it was important to interpret the term “depletion” in light of both the disclosure of patent and the common knowledge of skilled persons. He opined that the skilled person would understand the term to merely be a name the inventors ascribed to the layer without introducing any further requirements, affirming that the inventors could have named this layer anything as it is “just a name.” The Court criticized this approach, finding it made the word depletion meaningless, effectively ignoring the inventors’ choice of an additional term to describe this layer of the metal particles.
Tekna’s main expert construed the term “depletion layer,” by consulting the disclosure of the patent to better grasp the meaning of the term, as a skilled person would do in the circumstances. The Court agreed. One of the questions, which was applicable to both patents concerned the meaning of “depletion”. The Court interpreted the term “depletion” as a reduction in concentration of atoms of the additive gas over the thickness of the layers. The Court determined that the skilled person would not understand the component of the additive gas to be necessarily present in the “depletion layer” in the form of reaction products between the additive gas and the reactive metal source, or to be present by diffusion. The Court determined that the skilled person would not understand the component of the additive gas to necessarily be present in the “depletion layer” in the form of a reaction product between the additive gas and the reactive metal source, or to be present as a result of diffusion.
Invalidity of most claims of the patents on the basis of ambiguity
Courts have a general “disinclination to find a claim invalid for ambiguity” as patents are to be read in a way that is sympathetic to accomplishing the inventor’s purpose, with a mind willing to understand and not one desirous of misunderstanding.
A patent holder should know what they own, and the public should know what they do not. According to section 27(4) of Patent Act, a claim of a Patent must “define distinctly and in explicit language the subject-matter for the invention” for which an exclusive property or privilege is claimed. Otherwise, a patent claim may be found invalid for ambiguity.
Application to the 502 Patent
: for the 502 Patent, each of the claims requires, as an essential element, a powder particle having a “depletion layer” that is deeper and thicker than the native oxide layer. The Court found the claims did allow the skilled person to determine whether or not the Patent claims would apply to a process of producing a metal dust as the skilled individual would not be able to determine if a particle of powder had a “depletion” layer that was deeper and thicker than a native oxide layer. AP&C was not able to show how a skilled person would distinguish between the “depletion layer” and the native oxide layer, so as to confirm their existence and compare their depth and thickness even if it was assisted by three experts in the field who collectively prepared six expert reports; conducted various tests in a university and a specialized lab; and had over three years to prepare their answer.
Application to the 236 Patent: as for the 236 Patent, the majority of the claims were also found invalid for ambiguity for similar reasons. A few claims in the 236 Patent, however, were not ambiguous because they described how to determine whether a “depletion” layer exists by defining the boundaries and minimum depth of the “depletion” layer (in tens of micrometers). Thus, the Court held that a skilled person would be able to determine whether a process falls within one of these unambiguous claims.
AP&C’s arbitrary and subjective comparative testing approachThe challenges AP&C faced in demonstrating infringement further confirmed the Court’s determination of ambiguity. AP&C tested different samples of Tekna powders to prove Tekna infringed on AP&C patents. AP&C relied on positive controls, AP&C powders prepared with additive gas, and negative controls, AP&C powders prepared without additive gas, but without establishing that the positive controls had a “depletion layer.” AP&C relied on positive controls, AP&C samples prepared with additive gas, and negative controls, AP&C samples prepared without additive gas but without establishing that the positive controls had a “depletion layer.”
AP&C’s use of its own powders as a baseline for comparison with Tekna’s powders helped solidify the determination that the claims in AP&C’s patent were not sufficiently clear for a skilled person to assess whether a powder falls within the scope of the claims. The Court rejected AP&C’s approach to testing because it cannot be done without the patent owner. This means that the patent does not fulfill its public notice function. Tekna brought insufficiency together with ambiguity.
The court noted the strong correlation between insufficiency, and ambiguity. Both grounds of invalidity are related to whether a patent specification adequately defines and describes the invention. A patent claim is invalid for insufficiency when the specification does not teach the person with the necessary knowledge how to implement all embodiments of an invention. The Court found that it was not necessary to make an additional insufficiency finding due to the overlap between the arguments of the parties for ambiguity. Nevertheless, the Court stated that for both patents (except for a few claims of the 236 patent excluded from the ambiguity determination) a skilled person would be unable to put the patent into practice as they had no way to determine whether a depletion layer was produced.
Concluding remarks
