Continuous Diligence Not Required

Although the United States has been a first-inventor-to-file patent system since March 16th 2013, the patents of the previous first-to-invent system will linger for many years to come. For those patents, the ability to “swear behind” prior art will remain.

Under pre-AIA §102(g), when two persons invent the same invention, for the latter inventor to be entitled to the patent, she must demonstrate that she (1) was the first to conceive of the invention and (2) was reasonably diligent in reducing it to practice. The Federal Circuit recently ruled on what, exactly, “reasonable diligence” entails at the Patent Trial & Appeal Board (PTAB) in Arctic Cat Inc. v. GEP Power Products, Inc. (here)

In Arctic Cat, the PTAB, while finding that an Arctic Cat employee had been the first to conceive of the invention at issue, rejected Arctic Cat’s claim that he had diligently worked to reduce the invention to practice. Focusing on the critical period between the filing of the cited prior art patent application and the filing of Arctic Cat’s application, the PTAB found that the timeline of important emails that Arctic Cat offered lacked a “sufficiently detailed explanation of events occurring between the bookend communications.” Specifically, the PTAB took issue with the fact that, in the timeline that Arctic Cat provided, “approximately half of the days” of the nearly six-month critical period were not accounted for, and that it lacked “specifics as to facts and dates.”

On appeal, the Federal Circuit noted that reasonable diligence “must be shown throughout the entire critical period, which begins just prior to the competing reference’s effective date and ends on the date of the invention’s reduction to practice.” (citing Perfect Surgical Techniques, Inc. v. Olympus America, Inc., 841 F.3d 1004, 1007 (Fed. Cir. 2016)). However, while diligence must be shown throughout this period, it “need not be perfectly continuous—only reasonably continuous.” That is, even periods of inactivity will not bar a finding of reasonable diligence: the critical point is that, “in light of the evidence as a whole, the invention was not abandoned or unreasonably delayed.”

Reviewing the evidence provided, the Federal Circuit observed that during the identified gaps, the invention was being tested by a company hired by Arctic Cat for that purpose. Given this activity, the court found that a “[l]ack of diligence cannot be inferred from putting the invention into someone else’s hands for needed testing and awaiting test results for a short period commensurate with the testing need, at least where oversight was diligent.” Failing to record progress – even on a monthly basis – doesn’t necessarily indicate a lack of diligence. Accordingly, the Federal Circuit reversed the PTAB’s decision, finding that the record confirmed Arctic Cat’s employee’s “diligent oversight.”

While a “rule of reason” is applied to all antedating evidence, it is exceedingly difficult in practice to assemble such evidence — years after the fact — on matters of conception and actual or constructive reduction to practice. To date, only a handful of Patent Owners have been able to successfully antedate prior art.