Updated November 11, 2020:

There are a number of ways to invalidate a patent but the most common is an attempt to locate prior art, which has more relevance to the patentability of a claim than the one cited by the USPTO examiner.

When determining whether a composition of matter, methods, apparatus, or product can violate a patent, the primary focus is on issues concerning validity and infringement. Here, infringement refers to the technology that falls under the jurisdiction of a patent claim. If such a technology exists and is within the patent's claims, the next step of evaluation concerns determining the validity of the patent. If the patent is found to be invalid, there is no infringement, whether the technology falls within the claims or not.

Although a U.S. patent is presumed as valid, its validity is rebuttable. To evaluate the validity of a patent, individuals should obtain a copy of the USPTO's file wrapper.

Contents of a USPTO File Wrapper

The file wrapper contains copies of the patent application as well as the communications between the USPTO and the applicant that ultimately resulted in the patent being issued. Reviewing the file wrapper enables you to determine the number and type of claims rejections made by the USPTO examiner, the grounds for making such rejections, as well as the prior art on record. Reviewing this information will provide insight into the representations or concessions that the applicant made and insights into what the USPTO thought was patentable.

How to Invalidate a Patent

By locating prior art that has more relevance than what's present in the file wrapper, individuals can often invalidate a patent. For instance, presenting prior art such as a publication or prior patent.

If such a prior art patent was issued within a one-year period before the application's filing date the effective prior art date becomes the application's filing date of the prior art patent. In the case of foreign patents and publications, the date of opening to the public or actual publication needs to be reviewed.

Providing Proof of Sale or Public Use

Another way to invalidate a patent entails providing proof that the invention was on sale or in public use in the U.S. within the past one year period before the date of patent application filing by the applicant. If it is proven that the invention was described in a publication, patented in a foreign country, or known by inventors in the U.S. before the applicant “invented” the invention, the patent becomes invalid.

Rules Determining the Patentability of an Invention

Before it can be patented inventions must be:

  • Useful: meaning that the invention serves some useful purpose.
  • Novelty: meaning that the invention has not been disclosed in any prior art reference
  • Obviousness: meaning that the invention, based on reference or combination of references, must not be obvious to another individual who is trained in the art pertinent to the invention.

When making decisions regarding these three rules, it may be helpful for the examiner to consult with experts in a relevant field. If possible, it's a good idea to obtain all information about the inventor's action in dealings with the invention. If it is found that the invention was derived from another, it renders the patent invalid.

Statues Governing Patent Applications

Statutes regarding patents stipulate that specifications should disclose all of the information necessary for another individual within the same field to construct and utilize the invention. It also stipulates that the specifications must contain the best way to do so.

If these stipulations are not met, the patent may become invalid. Also, the statutes stipulate that the specifications must conclude with at least one claim which distinctly states the specific subject matter that the applicant considers the invention. If this requirement is not met, it may also result in the patent being invalid.

The rationale behind these requirements is that applicants must clearly delineate between the rights that the patent protects and those that it doesn't. This enables third parties to have a clear understanding of what would be regarded as infringing on the patent.

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