Experimental Use Defense Law and Legal Definition

Experimental use defense is an exception applied to patent infringement. It offers a defendant an excuse to patent infringement when the use of the patented invention is for the sole purpose of gratifying curiosity or a philosophical taste, or for mere amusement.

In Madey v. Duke Univ., 336 F. Supp. 2d 583 (D.N.C. 2004), the court held that the experimental use defense is very narrow and limited to actions performed for amusement, to satisfy idle curiosity, or for strictly philosophical inquiry. Further, use does not qualify for the experimental use defense when it is undertaken in the guise of scientific inquiry but has definite, cognizable, and not insubstantial commercial purposes. Use is disqualified from the defense if it has the slightest commercial implication. Moreover, use in keeping with the legitimate business of the alleged infringer does not qualify for the experimental use defense.