Background
Minerva Surgical, Inc. holds U.S. Patent No. 9,186,208, directed to surgical devices for endometrial ablation — a procedure used to stop or reduce abnormal uterine bleeding by destroying the uterine lining. Hologic, Inc. (a competing medical device company and Minerva’s adversary in prior assignor estoppel litigation) argued that the ‘208 patent was invalid under the pre-AIA public use bar: a patent is invalid if the invention was in public use in the United States more than one year before the patent application’s filing date.
More than a year before the priority date of the ‘208 patent, Minerva had brought 15 fully functional prototypes of the device to an industry trade show and demonstrated them to attendees — sophisticated medical professionals and industry members who were under no confidentiality obligations. Hologic argued that this demonstration constituted public use that invalidated the asserted claims. The district court granted summary judgment of invalidity, and Minerva appealed.
The Court’s Holding
The Federal Circuit unanimously affirmed. The court analyzed the public use bar under pre-AIA § 102(b), which requires that: (1) the invention was in public use; (2) the use occurred in the United States; (3) the use occurred more than one year before the patent application was filed; and (4) the claimed invention was ready for patenting at the time of the use. The court found all four elements satisfied.
On “public use,” the court found the demonstration went well beyond mere display. Trade show attendees were allowed to observe the prototypes’ functionality in sufficient detail that a sophisticated viewer could determine how they worked — there was no confidentiality restriction, and the purpose of the demonstration was precisely to showcase the device’s operation to an industry audience. On “ready for patenting,” the court held that Minerva’s creation of 15 working prototypes that embodied every element of the asserted claims constituted a reduction to practice. The fact that Minerva continued “fine tuning” the device afterward did not negate readiness, since the prototypes already functioned as claimed.
Key Takeaways
- Demonstrating a fully functional prototype at an industry trade show, without confidentiality restrictions, to an audience that can observe how the device works constitutes “public use” under § 102(b) — it goes beyond mere display.
- A device is “ready for patenting” once working prototypes embody every element of the patent claims — subsequent refinement or “fine tuning” does not retroactively postpone the readiness date.
- The public use bar applies even if the inventor did not intend the trade show as a formal disclosure — the key is whether members of the public (here, sophisticated industry attendees under no confidentiality obligation) could understand how the invention worked from the demonstration.
- Companies that demonstrate products at trade shows, industry conferences, or customer events before filing patent applications should carefully assess whether those demonstrations constitute public use that could start the one-year clock under pre-AIA § 102(b) — or potentially constitute prior art under the AIA.
Why It Matters
Minerva Surgical v. Hologic is a stark warning for companies that take prototype products to trade shows before filing patent applications. The medical device, consumer electronics, and industrial equipment industries routinely debut products at major trade shows. This decision makes clear that demonstrating a working product — even without formal press releases or published literature — can trigger the public use bar if sophisticated observers can determine how the invention works and there are no confidentiality restrictions. A single trade show appearance can start the one-year clock that, if a patent application is not filed in time, will invalidate the patent.
For patent practitioners advising clients who exhibit at trade shows, the case reinforces the importance of a “file first, show later” strategy whenever possible. When pre-filing demonstrations are unavoidable for business reasons, the demonstration should be conducted under confidentiality agreements, limited to aspects that do not enable observers to understand the claimed invention, or otherwise structured to avoid triggering the public use bar.