Assignor Estoppel is Not Available in Inter Partes Review And No Distinction between Person having Ordinary Skill in US and Canada

July 31, 2014

DC Blog

In Redline Detection, LLC v. Star Envirotech, Inc., (IPR2013-00106, Paper 66, June 30, 2014) the Patent Trial and Appeal Board (“the PTAB”) held that the Petitioner, Redline Detection, failed to show by a preponderance of evidence that claims 9 and 10 of Star Envirotech’s patent no. 6,526,808 are unpatentable.

The ‘808 patent relates to methods for generating smoke for use in a volatile, potentially explosive environment.  For example, the ‘808 describes a method for generating smoke in which a flammable fluid is vaporized into smoke in an inert environment created within a smoke chamber.  The technology is widely used in vehicle emission testing.

Doctrine of Assignor Estoppel

The PTAB began its discussion with claim construction of several key terms, including the definitions of “flammable fluid,” “smoke,” “locating,” and “closed.”  The PTAB then addressed an argument from the Patent Owner that the Petitioner was barred from proceeding in the case due to the doctrine of assignor estoppel.

The Patent Owner contended that Kenneth A. Pieroni, a named inventor and assignor of the ‘808 patent, was in privy with the Petitioner and thus should be barred from pursuing inter partes review under the equitable doctrine of assignor estoppel.  (See Paper 66 at 12).  The PTAB considered the AIA, and decisions from the U.S. Supreme Court, Court of Appeals for the Federal Circuit and relevant U.S. District Courts and held that the equitable defense of assignor estoppel is not available in inter partes review.

Obviousness Analysis – Canadian vs. U.S. PHOSITA

            The PTAB then discussed the obviousness challenges to the claims.  After discussing the level of ordinary skill in the art, the Petitioner challenged the Patent Owner’s expert, Dr. Checkel, alleging that because Dr. Checkel worked in Canada for most of his life, he did not know what a person of ordinary skill in the art in the United States would know of smoke machines or evaporative emission control testing.  The PTAB noted that Dr. Checkel had worked on automotive research projects with the “Big Three” North American car manufacturers, and that inconsistent with the Petitioner’s argument, Petitioner had provided prior art from the U.S., Great Britain and Canada in order to ascertain the level of ordinary skill in the art.  Therefore, the PTAB held that it was not persuaded that a relevant distinction may be drawn between persons of ordinary skill in the United States and Canada.  (See Paper 66 at 16).

Obviousness – Gilliam in view of Stoyle

With respect to the Petitioner’s challenge to claims 9 and 10 as obvious over Gilliam (US 5,107,698) and Stoyle (GB 640,266), Petitioner alleged that Gilliam taught all the claim limitations, except for the use of inert gas to create an inert environment in the closed smoke-producing chamber.  Petitioner introduced Stoyle for teaching the use of an inert gas to generate smoke and reduce the risk of explosions.  (See Paper 66 at 22).

The Patent Owner argued that Stoyle teaches an apparatus that generates smoke only after the mixture of heated oil and carbon dioxide gas emerges from the apparatus, and therefore, does not disclose “producing smoke in an inert environment with a closed smoke producing chamber.” (Prelim. Resp. 19, 22).  The PTAB agreed with the Patent Owner, and was not persuaded that a person of ordinary skill in the art would have substituted Stoyle’s use of inert gas, in place of the air in Gilliam’s system.  Petitioner’s arguments were effectively rebutted by the testimony of Patent Owner’s expert.  Furthermore, Petitioner did not otherwise rebut Patent Owner’s expert’s conclusions with persuasive evidence.

Obviousness – Gilliam in view of Stoyle, Pauley and the 1999 Website

Petitioner attempted to rely on Pauley (GB 640, 266), and a 1999 internet webpage to teach the use of an inert gas to produce smoke and the use of the smoke to detect leaks in an automobile.  The PTAB, relying on the unrebutted testimony of Dr. Checkel, held that there was no reason to substitute the inert gas as taught by Pauley.  The PTAB noted that the Patent Owner had provided evidence of secondary considerations of non-obviousness, however, the PTAB did not consider these arguments as the Petitioner’s arguments had failed on primary grounds.  (See Paper 66 at 31).

Petitioner’s Motion to Exclude, Evidentiary Motions

            Petitioner sought to exclude several items of evidence submitted by the Patent Owner including declaration testimony, written articles, and exhibits as impermissible hearsay.  For example, Petitioner sought to exclude declaration testimony of Jim Saffie on the basis that the testimony was hearsay and that Mr. Saffie was not offered as an expert.    The PTAB held that it was not necessary to assess the merits of Petitioner’s motion to exclude because the testimony was submitted as objective evidence (secondary considerations) of non-obviousness.

The Petitioner also attempted to exclude a fuel tank and a charcoal canister (Ex. 2021) as not relevant, prejudicial, and misleading under Federal Rules of Evidence (Federal Rules of Evidence) 403.  Patent Owner argued that the Petitioner was merely challenging the weight of the evidence and not its admissibility. The PTAB held that a motion to exclude is not the proper vehicle to challenge the sufficiency of evidence. The PTAB did not consider the merits of the motion to exclude exhibit 2021 because without considering exhibit 2021, Petitioner had not presented sufficient evidence to demonstrate by a preponderance of evidence that claims 9 and 10 are patentable over the cited combination of prior art.  (See Paper 66 at 37).

Petitioner had also objected to a series of exhibits as irrelevant under FRE 403 and hearsay under FRE 801 and 802.  The PTAB noted that the Petitioner failed to identify any alleged improper portions of the exhibits with particularity.  In denying the motion to exclude, the PTAB held that, “such a general objection to these exhibits does not provide us with the information necessary to assess Petitioner’s reasons for seeking exclusion of these exhibits.”

Take Aways

In this decision, the need for thoroughly prepared and highly knowledgeable expert witnesses is underscored since the Petitioner could not rebut the testimony of the Patent Owner’s expert.  Furthermore, attempting to draw a distinction between a person having ordinary skill in the art in Canada and the United States may not be very effective, especially when using international patents to determine the ordinary skill in the art. It also appears that the doctrine of equitable assignor estoppel is not available as a defense in inter partes review.

Lastly, it appears that a motion to exclude is not a proper vehicle to challenge the sufficiency of evidence.  Objections to evidence under FRE 403, 801 and 802 should be made with particularity in order to provide the PTAB with sufficient information for seeking the exclusion of the exhibits.



David Collins


David is a member of the firm’s electrical and mechanical practice group. David practices in all ‎areas of patent law ‎with an emphasis on counseling clients on intellectual property matters, litigation of intellectual ‎property disputes, ‎and preparing and prosecuting patent applications in the areas of display devices, ‎telecommunications, ‎semiconductor design and fabrication, data storage systems, automotive electronics, light ‎emitting devices, ‎software, microprocessors, data encryption, circuit layouts, optics and image processing, in ‎addition to various ‎technologies in the mechanical arts. ‎

David earned his J.D. from American University Washington College of Law, where he was an articles editor on ‎the American University Business Law Review. He also holds a J.D. from the University of Ottawa, Faculty of Law ‎in Canada. David received his B.Eng. in Electrical Engineering from the Royal Military College with a focus on ‎communications and electronics. ‎

David is fluent in French.