Public Use of an Invention

The public use of an invention can invalidate your ability to obtain a patent in that invention. There are many nuances to the law on public use, and this will explore only one of the nuances. A patent cannot be obtained for an invention if the patent application was filed more than one year after the first date of public use. Thus, whenever a public use has occurred, there is a “critical date” one year later by which a patent application must be filed if patent protection is to be sought.

What is “public use,” though? There is a lot of case law defining this, but unfortunately it is, at the time of this writing, all old case law under the old patent rules.  It is fairly likely, though, that much of the analysis of most aspects of “public use” will be the same under the new patent rules.

The public use bar arises where the invention is in public use before the critical date and is ready for patenting. The test for public use includes consideration of many factors, such as evidence relevant to experimentation, the nature of the activity that occurred in public, whether and to what extent there was public access to the use, the existence of confidentiality obligations with members of the public who witnessed the use, and any commercial exploitation of the invention. Importantly, wide, public knowledge is not necessary for “public use” to have occurred. In some cases, hidden use of a device can be public us; if a new type of suspension is used in a truck that is driven around town for an afternoon, this may be public use even if no one sees the suspension. On the other hand, an inventor’s private use of the invention, for his or her own enjoyment is not a public use.

“Public use” of a claimed invention occurs when the inventor allows another person to use the invention without limitation, restriction or obligation of secrecy to the inventor. The existence of such controls can indicate that a use was not public, but is not necessarily dispositive of the issue.

It is important to understand that the above description is not at all a complete treatment of public use law or patentability requirements.  Every situation is a little bit different, and may be analyzed under these or other areas of patent law.  For that reason, each situation must be addressed on its own facts with the advice of competent counsel.