Key Takeaways

  • A public use patent bar prevents inventors from obtaining a patent if their invention has already been publicly used or commercially exploited before filing.
  • The USPTO applies a test that considers the extent of public access, confidentiality agreements, and whether use was secret or commercial.
  • Use patents protect new applications or methods of using an existing invention, distinct from improvement patents, which add new features.
  • Courts carefully examine confidentiality, commercial exploitation, and demonstrations when deciding whether public use invalidates a patent.
  • Inventors should file early and limit disclosure or sale to avoid losing rights under the “public use” bar.

Public use patent is the statutory prohibition against awarding a patent for an invention that is already publicly available. By definition, patents are designed to limit the use of an invention to the patent-holder and/or his or her licensees. Public use as a bar to an invention's patentability is described by section 35 of the U.S. Code, which states that patent protection is not available if an invention was described in a print publication anywhere in the world more than a year before the patent application was filed.

Protecting an Invention

Patents prevent others from using, making, or selling your invention. The U.S. uses a first-to-file patent system, which means the first person to file a patent application owns the rights to the invention. This means that if someone else learns about your invention and files a patent first, you will no longer hold the rights to your creation. For this reason, you should avoid disclosing, selling, or sharing details about your invention before seeking patent protection.

What Is a Use Patent?

A use patent refers to a patent that protects a novel method of using an existing product, process, or composition for a new purpose. This type of patent differs from improvement patents, which cover added features or modifications, because it focuses on applying something already known in a unique way. For example, discovering that a known chemical compound can treat a different disease may qualify for a new use patent if the application is novel and non-obvious.

Use patents are valuable in industries like pharmaceuticals, biotechnology, and consumer products, where the discovery of new applications for existing inventions can create significant commercial opportunities. However, these patents are scrutinized carefully to ensure they are not simply restating an obvious use.

Test for Public Use

To determine whether an invention is patentable under the American Invents Act (AIA), the United States Patent and Trademark Office (USPTO) examiners consider whether the invention has been offered to the public and/or has been exploited commercially by the inventor. The latter serves as a clear indication of public use.

Otherwise, factors that will be considered include the type of activity in which the invention was publicly available, the extent of public access, and whether those who observed the invention were required to sign confidentiality agreements. Depending on these factors, even one instance of public use can be used to contest a patent application.

While public use or sale of the invention keeps it from qualifying for patent protection, that is not necessarily the case for public knowledge unless:

  • The use was not secret and occurred in the course of commercial activities.
  • The use is traceable to a person other than the inventor who did not sign a confidentiality agreement.
  • Public use is open and has not been restricted in any way.

Use is not considered public if:

  • The invention is not on sale and cannot be used or made by others.
  • The invention is made available under a confidentiality agreement.
  • The invention is marked as confidential.
  • An expectation of secrecy has been created and the invention is not being commercially exploited.

Limits on Use Patents

While a use patent can expand protection for existing inventions, it cannot be granted if the new use was already in the public domain or suggested by prior art. The USPTO requires that the claimed use be:

  • Novel: Not previously disclosed in publications or patents.
  • Non-obvious: More than a predictable extension of an existing use.
  • Useful: Capable of providing a practical benefit.

If the new application has already been practiced openly or described in trade literature, it may fail under the public use bar. For instance, if a researcher presents a new medical use of a drug at a conference without confidentiality protections, this could prevent later patenting.

Factors To Consider

Keep in mind that public use of an invention is not always considered non-secret. In addition, non-secret use is not automatically public use, even if the invention is not hidden from public view. This is even true if the invention is being commercially used, provided that this use preserves its secrecy.

If the invention is put on display by the inventor or one of his or her friends, family members, or associates, the court considers this public use and it will disqualify the invention from patent protection. This is even true if the invention is totally or partially hidden or is being used in any publicly accessible area, such as an open research laboratory, and/or if the person who received information about the invention does not technically understand its workings.

The existence of a confidentiality agreement is considered as a factor in whether use of an invention is public, but it is not the only factor. The court noted in Bernhardt LLC vs. Collezione Europa USA that policies that bar public use of patentable inventions are necessary to avoid extending the period in which an invention can be exclusively exploited by the patent holder. In this case, the court considered an invention displayed in an exhibition hall that was only open to a list of authorized individuals whose IDs were checked by security. The people were escorted through the hall and were not allowed to take photos or notes.

If the inventor has only used the invention in spaces where he or she has a reasonable expectation of privacy for personal enjoyment only, this is not considered public use.

Inventions shared with another inventor without the expectation of secrecy or other restrictions are considered to be publicly used. The court will consider the circumstances under which the third party had access to use the invention. For example, if the invention was sold to the third party or otherwise used commercially, this likely constitutes public use.

Practical Examples of Public Use and Use Patents

Courts and examiners often rely on real-world contexts to determine whether an invention is disqualified. Some examples include:

  • Pharmaceuticals: A drug long used for one disease may later be patented for a different therapeutic use if that application was unknown and inventive.
  • Technology: A software algorithm repurposed for a new industry may qualify for a use patent if the adaptation is not obvious.
  • Consumer products: If a household chemical is later found to work as a pesticide, patent protection for that use could be possible, provided it was not publicly demonstrated earlier.

By contrast, if the invention was displayed at trade shows, used by third parties without confidentiality, or sold openly, courts are likely to find public use, invalidating the patent claim.

Frequently Asked Questions

  1. What is the difference between a use patent and an improvement patent?
    A use patent covers a new application of an existing invention, while an improvement patent protects added or modified features.
  2. Can I patent a new use of an existing drug?
    Yes, if the new use is novel, non-obvious, and not previously disclosed. Many pharmaceutical companies rely on use patents to expand protection.
  3. How does public use affect patent eligibility?
    Any public disclosure, demonstration, or sale of an invention more than a year before filing can bar patentability under U.S. law.
  4. Is experimental use considered public use?
    No. Courts recognize a distinction between experimental testing (under controlled conditions) and unrestricted public use, which invalidates a patent.
  5. How can I protect my invention before filing?
    Avoid disclosing or selling it publicly, use confidentiality agreements, and file a patent application as early as possible.

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