Patent Infringement Defenses

Where You Need a Lawyer:

(This may not be the same place you live)

At No Cost! 

 What Is a Patent?

A patent is a type of intellectual property right. It gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time. In exchange for this right to exclusive use, the patent owner publishes a comprehensive disclosure of the invention. In most countries, including the U.S., patent rights are a matter of private law. A patent holder must sue any person who infringes on the patent to enforce their right to exclusive use. In some industries patents give their owners a vitally important competitive advantage.

Most U.S. patents are valid for 20 years from the date the application is filed with the United States Patent and Trademark Office (USPTO), an agency of the federal Department of Commerce. Exceptions are sometimes made to extend the term of a patent. U.S. patents are only valid in the United States. If a person wants patent protection outside of the United States, they must research the intellectual property rights of other nations and apply for protection with the foreign nation’s patent authorities.

There is also the Doctrine of Equivalents. This doctrine protects a patent owner from another person creating a product that is basically the same product that is protected with only a few minor modifications, i.e. an equivalent product. In some countries, such as the United States, there is liability for another two forms of infringement.

One is contributory infringement, which is participating in the infringement committed by another person. For example, one company might help another to create a patented product or sell the patented product which has been created by another company.

In the U.S., a person or company can also be liable for inducement to infringement, which is when a party induces another to violate a patent or assists another party in a violation. An example of this would be a company paying another company to produce a patented product in order to reduce their competitor’s market share.

How Are Patents Enforced?

Patents can generally only be enforced through civil lawsuits. In the U.S. this would be a lawsuit for patent infringement in a U.S. federal district court. Typically, the patent owner seeks monetary compensation for a past instance of infringement, and also an injunction that prohibits the defendant from engaging in future infringement. In a civil lawsuit for patent infringement, the burden of proving infringement rests with the patent owner.

Patent infringement is a violation of a patent owner’s rights with respect to a patented invention. Unless the owner of a patent gives their permission, usually in the form of a license, the making, using, offering to sell or selling of an item that is patented is patent infringement. The infringement must be done in the United States. Or, infringement can be committed when a product that violates another’s patent is imported into the United States after it is produced in a foreign country.

Are There Any Defenses to Patent Infringement?

A person who has been accused of patent infringement has a number of defenses that they can assert to avoid liability. Even if the person seems to have infringed on a patent, there are situations in which the person can avoid responsibility.

The best way to excuse a person from a claim of patent infringement is to claim either that the patent is unenforceable or that the act of infringement is permitted under federal patent law.

When Are Patents Unenforceable?

Some of the common situations in which patents are unenforceable are as follows:

  • Patent Invalidity: Although a patent that has been issued by the USPTO is presumed to be valid, a person can challenge the validity of a patent by offering evidence that the patent holder in fact failed to meet the requirements for a patent. For example, a person who wants to challenge the validity of a patent could produce a prior invention to prove that the patented invention was not novel;
  • Inequitable Conduct: Even if the patent is valid, it may be unenforceable if the patent owner was fraudulent in getting the patent. For example, if the patent owner intentionally misled the USPTO regarding some material information, the patent would not be enforceable.

Since claims of inequitable conduct are essentially claiming that there was fraud in the patent application process, the person charged with infringement must identify specific actions which constitute misconduct. Two elements must be proven for this patent infringement defense to be valid:

  • Deceptive Intent: Negligently leaving out information does not qualify as inequitable conduct. It must be proven that the patent applicant’s intent was to deceive the USPTO by deliberately withholding information it knew to be material to their application;
  • Materiality of the Information: The information withheld must be material, or centrally important, to the patent application. A “but-for” test is used to determine whether or not the patent examiner would have refused a claim if they had had the information that was omitted.

In some cases, it is not necessary to show materiality. If the court believes that egregious misconduct occurred during the patent application process, they may accept inequitable conduct as a patent infringement defense.

  • Delay in Bringing Suit: if the patent owner delayed in bringing the infringement lawsuit unreasonably and without a good excuse from the time of learning of the infringement, the owner may lose their right to enforce their patent;
  • Patent Misuse: If the patent owner has used their patent to become a monopolist or to violate antitrust laws, or if the owner has a record of bringing bad-faith claims of infringement, their patent may be unenforceable. The following are examples of patent misuse:
    • Requiring that royalties be paid for invalid patents;
    • Engaging in price fixing;
    • Purchasing all patents in the relevant market in order to limit competition;
    • Requiring buyers not to do business with competitors as a condition of purchasing a patented item;
    • Violating any antitrust laws.

If a patent owner engages in these actions, they could lose the right to enforce their rights. In some instances, though, the owner may be allowed to end their abusive practices and validate their rights again.

  • Estoppel: Alleged infringers can also claim that an inventor or owner is precluded, i.e. “estopped” in legal terminology, from suing based on their prior behavior. Equitable estoppel occurs when a party believes the owner had no intent of enforcing their patent because of prior assurances to the effect that they would not, or a lack of enforcement activity. For this defense to be valid, the accused infringer must have engaged in actions – to their own detriment – based on this belief.

Estoppel may also serve as a patent infringement defense if prior assertions of the patent owner are contrary to the rights they are currently claiming. If their application included limitations of rights or they previously made statements that had the effect of limiting the scope of their patent during litigation or hearings of the Patent Trial and Appeal Board, they cannot later claim to have these rights. These actions may preclude the filing of an infringement action.

Estoppel, inequitable conduct and laches are all types of what is called an “equitable defense” in legal terminology. Although these defenses can be used to avoid liability, courts have held that a patent infringer’s belief in the invalidity of a patent is not an acceptable defense to a charge of patent infringement.

When Is Infringement Permitted under Patent Law?

Some of the situations in which infringement is permitted under patent law are:

  • Implied license: An sale of a patented article authorized by the patent owner gives the buyer of the article an implied license to use it;
  • First Sale: An authorized sale of a patented article also gives the buyer the right to sell that particular patented article to a third party;
  • Repair: The owner of a patented item has a right to repair it and to replace its unpatented component parts as they wear out. However, the owner does not have the right to completely reconstruct the item after it has been used up;
  • Experimental Use: A person can infringe on a patent if they do it for the purposes of pure research and experimental use. However, use of a patented article for commercial purposes makes the experimental use inapplicable.

Should I Consult a Patent Lawyer about Possible Defenses to Infringement?

If you have been accused of patent infringement, an experienced patent lawyer can explain the complicated patent system to you. Clearly some issues in the area of patent law can be highly technical. They can analyze the facts of your case and tell you what defenses may be available to you given the facts of your situation.


16 people have successfully posted their cases

Find a Lawyer