Guest post by Professors Jonathan S. Masur (Chicago Law) and Lisa Larrimore Ouellette (Stanford Law).

What is it that makes a use “public” for purposes of the public use bar? Does it matter whether the person doing the using is a member of the public, as opposed to the inventor? Or does it matter whether the use is itself in public, as opposed to taking place in secret behind closed doors? As it turns out, the answer to both questions is “yes,” but the questions are not as distinct from one another as that formulation might make it seem. Instead, the issue of who is doing the using turns out to affect where and how that use must occur if it is to be public use.

Begin with the question of who is doing the using. Most cases of “public use” have involved use by at least one member of the public—“a person other than the inventor who is under no limitation, restriction or obligation of secrecy to the inventor.” And when an invention is in use by a member of the public (rather than the inventor), it is blackletter law that the use can be “public use” even if it takes place entirely in secret, behind closed doors. In addition, it is also blackletter law that the use need not enable the invention to constitute prior art. No member of the public needs to see all the details of the invention or be able to reproduce it—it is enough that at least one person has come to rely on the availability of the invention free from any patent-based restriction.

But as we explain in a forthcoming article, a small line of cases suggests there is a second route to public use: even if no member of the public uses the invention, an invention can be placed in public use if it is used by the inventor, but only if it is displayed to the public in such a way that the relevant public could have understood the invention. That is, there can be public use without the public using, but only if that use is out in the open and with something like an enablement requirement. See Real-World Prior Art, 76 Stan. L. Rev. (forthcoming 2024). These cases appear to rely on an idea of constructive public knowledge: just as a conference poster can be invalidating printed publication prior art if a researcher could have learned about the invention by reading it, an inventor’s demonstration of an invention can be an invalidating public use if someone could have learned about the invention from observing the demonstration. Likewise, the Federal Circuit has held that display of an invention is not public use “if members of the public are not informed of, and cannot readily discern, the claimed features of the invention.” The only exception to these rules has come when the inventor is engaged in secret commercial use of the invention. Some courts have held that this puts the invention into public use. But more recently, the Federal Circuit has instead begun to hold that this places the invention on sale, because the whole point of the use is to exploit the invention commercially. We agree with the Federal Circuit panels that have held that the on sale bar is a better fit in these situations.

The upshot from these two lines of precedent is that the question of whether an invention is in public use depends intimately on who is doing the using. If the user is someone other than the inventor, then there is public use (a) even if the use is taking place in secret, and (b) irrespective of whether the user can figure out how the invention works (enablement). But if the inventor herself is the one doing the using, then (a) the use must be taking place in public, and (b) the use must be enabling.

As one might predict, the grouping of these two approaches under the single heading of “public use” has led to confusion among litigants and, in some cases, courts. Two new Federal Circuit decisions this month add to this “public use without the public using” line of cases and demonstrate the pitfalls of failing to keep the interlocking public use rules straight. In Minerva v. Hologic, the court held that display and demonstration of a medical device at a gynecological trade show constituted public use. The patentee, perhaps misunderstanding this line of doctrine, argued that it could not be public use because no member of the public used the invention. But the court held that “public use may also occur where, as here, the inventor used the device such that at least one member of the public without any secrecy obligations understood the invention.” Similarly, In re Wingen held that display of an inventive “Cherry Star” flowering plant at a private Home Depot event placed the plant into public use. The patentee argued that the display did not disclose the claimed genetics of the plant—which could have been a successful argument given the enablement-like inquiry imposed on other similar cases—but the court held that this argument was forfeited because it was not raised in proceedings below. It seems likely that the lawyers who argued the case before the PTAB had not thought to make this argument because they did not realize that use by the inventor requires enablement. Our article includes numerous examples of district courts that were similarly confused by the rules that vary depending on who’s doing the using.

As we explain in our article, treating enabling demonstrations by the inventor as prior art makes sense as a matter of patent policy. But lumping these cases under the “public use” umbrella has created confusion and mistakes among the lower courts. Going forward, we think the Federal Circuit should be explicit that there are two distinct routes to public use: (1) use by a member of the public—someone under no obligation of confidentiality to the inventor—which can take place in secret and need not be enabling, and (2) use by the inventor, which must take place in public and enable the invention.

Alternatively, and perhaps even better, the Federal Circuit could decide that the inventor-use category of activities instead implicates the “otherwise available to the public” prong of § 102. An enabling demonstration, where the public learns about the invention but cannot use it, could be the paradigmatic example of an activity that makes an invention available to the public without creating any other type of prior art. This is not a full solution given all the pre-AIA patents still in force, and in light of the strong policy reasons for barring pre-AIA patents that were displayed publicly we can see why courts have tried to fit these cases within the “public use” category. Regardless, for patentees and their attorneys, Minerva v. Hologic and In re Wingen serve as a reminder to avoid disclosing the details of an invention before they are ready to file a patent application—and if a disclosure does occur, they should remember to preserve the argument that it wasn’t actually enabling!