A patent is a property right granted by the US government. The government is authorized to grant patents by Article I, section 8 of the Constitution which reads, "Congress shall have the power . . . to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." The right that Congress grants is the right "to exclude others from making, using, offering for sale, or selling" the invention in the United States.
An inventor does not need a patent to make, use, or sell the invention himself but he or she does need to obtain a patent in order to prevent others from doing so. Even after a patent is obtained, the owner of the patent does not have the right to use, make, or sell an invention if doing so would violate the law.The patent right is granted for a limited time in exchange for a full disclosure of the invention. The disclosure must be sufficiently detailed to allow a person of ordinary skill in the art to make and use the invention. A patent granted by the US government only protects the invention within the United States and its territories and possessions. Foreign patents can also be obtained to protect the invention in other countries.