How Can a Patent Be Invalidated?

Rich Goldstein

Founder & Principal Patent Attorney

Navigating the maze of patent invalidation can be difficult. As a seasoned expert in intellectual property law, I’ve witnessed first-hand the challenges inventors face when their patents are at risk. 

Join me as we unravel the complexities, understand common pitfalls, explore strategies to safeguard your innovation, and determine if a patent can be invalidated.

How Can a Patent Be Invalidated?

A patent can be invalidated in numerous ways. Some of these include:

  • Proving the invention has already been on sale (or been available for use publicly)
  • Conducting prior art searches
  • Reviewing initial claim rejections
picture of two women discussing documents

If an invention has been on sale or available for public use within 12 months of the patent application being submitted, it can be invalidated. 

Examining prior art within the patent’s lineage or scrutinizing citations associated with the patent, including citations of cited patents, can serve as valuable ammunition for mounting an invalidation.

Through uncovering prior art that is more relevant than the contents of the file wrapper (documents the invention’s history), individuals frequently hold the key to patent invalidation. This could involve introducing prior art, like a publication or previous patent, to challenge the patent’s validity.

Patent Invalidity Search Explained

A Patent Invalidity Search is an extensive inquiry focused on locating prior art that has the potential to challenge the validity of an existing patent. This in-depth search is conducted to uncover any information not considered by a United States Patent and Trademark Office (USPTO) patent examiner the first time, information that might challenge the patent’s novelty, non-obviousness, or utility. 

By analyzing a wide range of sources, including patents, scientific literature, and technical documents, the search aims to provide evidence that questions the validity of the patent’s claims. This process is crucial in legal disputes, licensing negotiations, or seeking to clear the way for innovations.

How to Challenge a Patent’s Validity

Trying to invalidate a competitor’s patent if you consider it unworthy or are worried something you are doing may encroach upon their patent is possible.

The case can be brought to numerous courts when challenging a patent’s validity, depending on specific scenarios and limitations. In most circumstances, you can argue the validity of a patent by taking the case to one of the:

  • Federal District Court – Serves as a trial court that handles a wide range of cases involving federal laws, regulations, and disputes between parties from different states or involving federal issues.
  • Patent Trial and Appeal Board (PTAB) – Responsible for overseeing various proceedings related to patents, including inter partes reviews (IPRs), post-grant reviews (PGRs), and other patent-related disputes.

A “case or controversy” is required at Federal District Courts. This principle in the legal system stipulates that courts should only hear and decide cases in which there is an actual dispute between parties. In the PTAB, this is not required. Instead, there is a petition phase and a trial phase.

Costs and requirements differ depending on what route you take (currently, the PTAB costs far less), so it is recommended you consult with a patent attorney for expert advice on what is the right decision for you.

a document with a copyright symbol

Steps of Challenging a Patent’s Validity

  1. Research Prior Art – Identify existing information that predates the patent.
  2. Consult Experts – Seek advice from patent attorneys or patent experts.
  3. File a Petition – Submit a challenge to the Patent Trial and Appeal Board (PTAB).
  4. Evidence Submission – Present evidence, including prior art, to support invalidation.
  5. Proceedings – Engage in proceedings, including hearings and responses.
  6. Decision – The PTAB issues a decision on patent validity.

Prior Art

The primary approach to patent invalidation involves finding prior art that predates the patent’s priority date and corresponds to the patented invention. This standard tactic challenges patent validity by asserting the invention is either apparent or already known, aiming to nullify the patent.

Questioning the Invention’s Existence

While many routes invalidate a patent, the fundamental query should be its actual submission for patenting, not mere product use. If a patent is deemed invalid, it means the invention should never have been granted the patent in the first place.

Sometimes, a product that is in use is not patented correctly. You may be surprised to find the product you wish to be invalidated does not have a patent in the first place.

Break in Priority Chain

A “break in priority chain” refers to a situation where the continuity or linkage between different patent applications is disrupted or lost. In the context of patent law, a priority chain is established when a subsequent patent application (such as a continuation or divisional application) is based on an earlier filed application (typically a provisional or non-provisional application). 

A break in this chain can occur if there are inconsistencies, omissions, or errors in filing the subsequent application, leading to the potential loss of certain rights or benefits associated with the original filing date. What is the possible result? An invalidated patent. 

The Importance of the Inventor’s Declaration

During the application process, an inventor must make a declaration or make an oath declaring who the inventor is. In some patent law cases, there will be more than one inventor that needs to be declared under oath.

More often than not, an inventor is listed on the patent application wrongfully. This could be someone linked to the product yet has no connection to the actual initial invention. Patent examiners regard this as “misrepresenting inventorship under oath.”

image of a patent for a camera

Additional Questions

How Long Is a Patent Valid? 

How long a patent is valid can vary. However, a product generally gains protection from its patent priority date or, often its filing date. This safeguard can hinder market competition, which is vital for survival in specific sectors. A U.S. utility patent lasts around 20 years, whereas design patents last for 14 years. Validation and renewal fees vary based on USPTO charges, legal and drawing expenses.

What Are the Grounds of Invalidity of a Patent?

The main grounds for the invalidity of a patent are:

  • Lack of novelty
  • Double patenting
  • Obviousness (must be non-obvious)
  • Failure to be useful to the public (unable to live up to claims)
  • Sufficiency Of Disclosure (must be described accurately when applying for a patent)

It is best to consult with a patent attorney to check whether a patent falls under these categories.

On What Basis Can Patents Be Overturned?

Patents can be overturned on various grounds, such as:

  • Invalidity 
  • Prior Art
  • Inequitable Conduct
  • Antitrust Violations
  • Improper Subject Matter
  • Non-Enablement
  • Fraudulent Activity
  • Licensing or Contractual Violations


Extensive research is required if a patent is to become invalidated. Whether you want a competitive advantage, more freedom to operate business activities, or wish to challenge weak patents, specific grounds need to be met for invalidation.

Considering 3,000 of the fully reviewed 3,572 patents by the PTAB be invalid, it is not uncommon for granted patents to be revoked. Consult with a patent attorney for further help and support. 

Is it Time to Protect Your Ideas?

Book your FREE Idea Protection Strategy Call

Join over 10,000 others who have asked us to help protect their best ideas and inventions.

Do You Have Intellectual Property (IP) You Need To Protect?

Your FREE Strategy Call is a pressure-free, no obligation way to get all your questions answered.
Goldstein Patent Law patiently listens to you, and then explains your options so you don’t lose your rights.
Call (718) 701-0700 or use the form below to secure your complimentary strategy call now.

By clicking Schedule Now, you agree to our Privacy Policy, including our Cookie Use.

No Obligation. Completely Confidential.


We're Social

Is it Time to Protect Your Ideas?

Book your FREE Idea Protection Strategy Call

Join over 10,000 others who have asked us to help protect their ideas.