What Is Patent Invalidity and What Do Entrepreneurs Need to Know About It?

By Hailey Pooler

Patent applications are reviewed by examiners who work at the United States Patent and Trademark Office (USPTO). The patent examiner completes research to determine if the invention was already publicly known before the application was filed. The examiner searches for patent references, publications, and available products—collectively known as “prior art”—indicating a claimed invention already exists.

Patent examiners have many applications to review and research. In some instances, the patent examiner may fail to identify prior art that shows the invention is not novel and/or non-obvious. Unaware of the prior art, the patent application may be granted. In these situations, an invalid patent may have been awarded. Situations like this created the need for “patent invalidity searches,” which can lead to litigation.

Before further examining patent invalidity, it is useful to review some basic patent application information:

Q: What are the requirements for a valid utility patent?

A: To be valid, a patent must …

  1. Have patent-eligible subject matter—Some subject matter is not patentable. In the United States, for example, laws of nature, physical phenomena, and abstract ideas cannot be patented.
  2. Be properly disclosed—A patent must disclose the “inventive aspects” of the invention and include an “enablement” in the application. The applicant is obliged to disclose any art they are aware of and indicated how the invention is distinct from prior art.
  3. Not already be patented—There cannot be multiple patents for the same invention.
  4. Be novel—The invention must be new and not incorporate all the elements of a previously disclosed invention.
  5. Serve some predetermined and “useful” purpose.
  6. Be non-obvious—The invention cannot be one “that would be obvious to a person of ordinary skill in the art at the time of the invention.”

Q: How long is a utility patent valid for?

A: A US utility patent is usually valid for 20 years from the patent priority date. The patent priority date is typically the date that the patent was filed, but that is not always the case.

Q: What is a patent invalidity search?

A: Patent invalidity searches are generally conducted by competitors or defendants in an infringement claim, and they are conducted after a patent is issued. This “extensive prior art search” has the goal of invalidating a patent using any prior art that may have been missed by the USPTO. A patent invalidity search differs from a normal prior art search in that a patent invalidity search focuses on the claim language of the patent instead of the overall invention idea.

Q: What is the purpose of a patent invalidity search?

A: The purpose is to find any important prior art that had been missed by the patent examiner. This search can support a challenge to another person’s patent or can help defend against an allegation of patent infringement.

When considering a challenge to—or defense of—a patent’s validity, it is essential that there be a good understanding of the patent in question. There are multiple ways to invalidate a patent:

  1. Examine the “file wrapper”—Every patent examined at the USPTO has a file wrapper that documents its history. This includes all the communications and documentation relating to the application by both the examiner and the applicant. A review of the initial claim rejections, the reason for such rejections, and the listed prior art already given in the history may point to similar claim language in other patents signaling a possibly weak patent with a high chance of being invalidated.
  2. Conduct an extensive prior art search—Looking at prior art in the same family as the patent at issue (or looking at any citations for the patent or even citations of the cited patents) also can be useful for an invalidation claim.
  3. Prove that the invention was on sale or available for public use—A patent can be invalidated if, within the 12 months prior to the filing of the patent application, the invention was on sale or available to the public in the United States, patented in another country, discussed in a publication, or recognized by other inventors in the US before invention by the applicant.

Ultimately, a patent invalidity search is similar to a general prior art search, but with a more specific goal. Instead of trying to find all prior art that relates to an invention or potential patent, invalidating a patent involves research specific to a single patent that is either being defended as valid or prosecuted as invalid.

This type of specific search underscores the importance of completing a comprehensive search for prior art as part of an well-developed intellectual property strategy. The Innovation Law Center (ILC) at Syracuse University College of Law can help innovators with this process by conducting general prior art searches as part of its services.

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