Public use == “accessible to the public.”

by Dennis Crouch

Bottom line in this new Minerva case — file your patent application before bringing a new product to a trade show. 

The Old Case: The battle between Hologic and Minerva went to the US Supreme Court in 2021; with the Court retained the doctrine of assignor-estoppel that bars a patent assignor from later challenging the patent’s validity or enforceability. Minerva Surgical, Inc. v. Hologic, Inc., 141 S. Ct. 2298 (2021). Although the doctrine remains, the Court narrowed its scope to only apply , but narrowed its scope to cover only situations where assurances (implied or express) made at assignment are later being undermined.  Thus, when claims are materially broadened post-assignment, the assignor should probably be permitted to challenge those claims.  As is true in many inter-corporate battles, the legal claims are being fought along different lines in various tribunals and cases.  This week, the Federal Circuit issued a new decision — this time involving upstart Minerva as the plaintiff suing Hologic for infringing its U.S. Patent No. 9,186,208.

Minerva’s ‘208 patent claims a device for endometrial ablation  and includes a 2011 priority filing date.  As you can see from the diagram above, the device includes both inner and outer frame elements, and the claims require that these “have substantially dissimilar material properties.”  This allows portions of the device to retain more flexibility (those coming in contact with the uterine lining) with other portions having more strength/durability.  Still, the whole head needs to be collapsible as well.

The application was filed in 2011, but back in 2009 Minerva had been doing testing on a prototype “Aurora device” that included inner/outer frames made of two different types of steel.  The devices were brought to a trade show (AAGL 2009) and Minerva gave a presentation on the device and distributed a brochure. It was also pitched to a potential acquirer.

In the appeal, Minerva provided three arguments as to why this activity was not an invalidating public use:

  1. Displaying the device at a trade show table does not count as a “use”
  2. Although the displayed device used two different types of steel, they were not different enough to satisfy the claim requirement of having “substantially dissimilar material properties.”
  3. The invention was not yet “ready for patenting” and therefore its public use was not disqualifying.

The Federal Circuit rejected each of these arguments in-turn.

Public Accessibility equals Public Use: Although the statutory language of “public use” suggests that the bar is triggered only if the invention is actually used.  The Federal Circuit explained here hat its interpretation is more expansive, and includes situations where the patentee made the invention “accessible to the public.” See, Delano Farms Co. v. California Table Grape Comm’n, 778 F.3d 1243 (Fed. Cir. 2015).  Here, the Aurora device was made available to attendees at a major trade show spanning several days.  Minerva brought 15 fully-functional devices and internally reported “lots of interest” and that the table was “busy.”

In Motionless Keyboard Co. v. Microsoft Corp., 486 F.3d 1376 (Fed. Cir. 2007), the Federal Circuit seemed to have ruled that public use requires use. Although publicly shown, the claimed keyboard was deemed not in public use since it was “visually displayed … without puting it into use [and] was never connected to be used in the normal course of business to enter data into a system.” Id.  Here in Minerva, Judge Reyna distinguished Motionless Keyboard, noting that Minerva’s disclosures were “well beyond” what was seen in that prior case.  The court focused on the sophistication level of the trade show attendees and their ability to closely scrutinize the device and see how it operated.

The inescapable conclusion … is that Minerva allowed knowledgeable individuals to scrutinize the invention enough to recognize and understand the SDMP technology Minerva later sought to patent.

Slip Op.  On appeal, Minerva argued that its prototype’s inner/outer frames did not have substantially different material properties.  On appeal, the federal Circuit also rejected that argument since Minerva materials from that time touted the benefits of the device’s SDMP.

Ready for Patenting: Public use only creates a bar to patenting if the invention was “ready for patenting.” Here, the court concluded that it was ready for patenting since (1) it had been reduced to practice; and (2) Minerva had sufficient documentation prepared describing the invention.

At the time, Minerva was still working to improve the technology and it had not yet been used to actually perform ablation on a living human.  On appeal, the Federal Circuit noted that no evidence (beyond common sense) indicates that the device’s only use is on live human tissue.  The court also noted that Minerva had conducted lab studies sufficient to move-on for clinical trials on humans.  Minerva’s final product used slightly different materials, but the court concluded that Aurora was still itself ready for patenting. “later refinements” and “fine tuning” go beyond reduction to practice and do not negate a public use.

5 thoughts on “Public use == “accessible to the public.”

  1. 1

    Bottom line: Tell the Patent Office before you tell anybody else (what your invention is).

    When thinking about Trade Shows, let’s distinguish between showing a prototype and showing the invention. To drum up interest, one might want at an important Trade Show to “tout” what your (black box) prototype can do, without “making available” how it achieves that result.

    Even here, I can imagine a demonstration of the prototype’s combination of deformation properties while keeping undisclosed how they are achieved. How much of “the invention” is “made available” when that happens? Or perhaps it doesn’t matter, if touting is all it takes to constitute “use” of an ivention.

      1. 1.1.1

        No. But I can make a presentation of the capabilities of a new product without revealing what the new product is. I’m presenting the performance but keeping as a secret how the new product works. Am I prsenting then “the invention”?


          Per the link, YES (that’s why I provided it as a reminder).

          The disqualifying “use” there did NOT divulge the items included in the utility patent of the plant – but to the court, that simply did not matter.

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