Patent Misuse

In United States patent law, patent misuse is an affirmative defense used in patent litigation when a defendant has been accused to have infringed a patent. It has also been used to mitigate damages following a finding of infringement or justify a failure to pay contracted-for royalties. This umbrella term usually describes any of the following:

• a violation of antitrust laws
• improper expansion of the scope or term of the patent
• inequitable conduct in the procurement or enforcement of a patent (sometimes termed "non-purgeable misuse").

In the United States, a patent is a statutory right that grants the patentee the right to exclude others from making, using, or selling a patented invention. Under current U.S. patent law it is not patent misuse simply to enforce rights to a patent, in good faith, and enforcement is permissible irrespective of any use or non-use by the owner.

The United States Supreme Court established the underlying "unclean hands" principle of the patent misuse doctrine in Motion Picture Patents Co. v. Universal Film Mfg. Co. The specific rule that similar misuse of a patent is a defense to an infringement suit comes from Morton Salt Co. v. G.S. Suppiger Co.,

Most types of misuse can be "purged" by abandoning the practice and causing its effects to dissipate. Fraud or inequitable conduct in patent procurement, however, is not purgeable.