Bloomberg Law
Feb. 22, 2023, 10:05 AM

File for Patent Before Publicly Displaying Tech, Attorneys Warn

Kelcee Griffis
Kelcee Griffis

A pair of recent Federal Circuit decisions affirming that technology previously displayed publicly isn’t eligible for patent protection should make inventors wary of exhibiting their inventions too early, attorneys say.

The US Court of Appeals for the Federal Circuit found last week in a precedential decision that a medical device shouldn’t have been issued a patent after it was shown at a trade event likened to the gynecologic industry’s Super Bowl.

It also ruled in early February that a Home Depot event that exhibited a “Cherry Star” flower was enough to prevent the plant’s seeds from later gaining patent protection.

Taken together, the decisions are a reminder that inventors must file to protect their discoveries before sharing their breakthroughs with the public, said Lisa M. Ferri, co-leader of Mayer Brown’s Global Intellectual Property Group.

“In both cases the patent holders lost their patent by prematurely introducing their product to the marketplace without sufficient safeguards,” Ferri wrote in an email.

Public Use

Under patent law, the two-pronged public use rule bars an invention from being protected if its concepts were previously made available to the public. It requires both the invention to be “in public use” and “ready for patenting” more than a year prior to the patent’s filing date.

In the Cherry Star seed patent case, the court found that the Home Depot agricultural expo constituted such a public use. However, it indicated that, had the plant been anything other than decorative, the public viewing analysis might have been different.

The court, for example, cited its 2007 Motionless Keyboard Co. v. Microsoft Corp. precedent, in which an ergonomic keyboard was displayed without being connected to a computer. Because the keyboard was not used for its intended purpose—to transmit data—the display wasn’t ruled a prior use.

“The only stated use for ‘Cherry Star’ is to be ornamental,” the opinion said. “The displaying of ‘Cherry Star’ at the Home Depot event was therefore undoubtedly a use for its intended purpose: ornament.”

As to the medical device—a Minerva Surgical Inc. design used for endometrial ablation to treat heavy menstrual bleeding—the display of 15 fully functional prototypes at the 2009 Global Congress of Minimally Invasive Gynecology was enough to undermine its patentability.

The court rejected arguments that the prototypes weren’t finished, or “reduced to practice,” because Minerva was still tweaking them.

“These cases simply emphasize that patent holders must be vigilant in following the requirements of the statute and relevant case law before taking a new product public,” Ferri said.

File First

Ashley N. Moore, managing partner at Michelman & Robinson LLP, agreed that the recent Federal Circuit activity “showcases how important it is to file for patent protection before you go public with an invention.”

Moore noted that the law doesn’t require the patent to have issued—it only mandates that the paperwork be filed. She said it’s a good idea to get the application process started early, especially because patent claims typically undergo significant changes during prosecution at the US Patent and Trademark Office.

Ferri also suggested that patent owners be honest about the extent to which they’ve discussed and displayed their inventions.

“Tellingly, in the Minerva case, Judge Reyna emphasized that the patentee was ignoring the clear evidence of a public use—and that is what doomed their patent,” she said.

Still, Greenspoon Marder LLP partner Robert J. Rando said the pair of decisions leaves gray areas about how public use displays will be interpreted against the Motionless Keyboard standard in the future.

For example, the Federal Circuit found that it was enough that doctors interacted with the Minerva device at the trade show, even though the device’s intended purpose was for use on a live patient.

“At the end of the day, I’m not sure these cases represent enough clarity on the public use doctrine,” he said.

Counsel and representatives for WinGen LLC, which sought the Cherry Star patent, and Minerva couldn’t be immediately reached for comment. Hologic Inc., the defendant in the Minerva case, declined to comment. The PTO didn’t respond to a request for comment.

To contact the reporter on this story: Kelcee Griffis in Washington at

To contact the editors responsible for this story: Jay-Anne B. Casuga at; Tonia Moore at