patent, in law, governmental grant of some privilege, property, or authority. Today patent refers to the granting to the inventor of a useful product or process the privilege to exclude others from making that invention. Patent is also the term for the conveyance of public lands to an individual. Patents developed out of the medieval institution of allowing monopolistic control over useful goods in order to encourage their sale and distribution; the authority was contained in letters patent (meaning open, i.e., public). The corrupt sale of such privileges and the consequent increase in the price of necessities led in England to the Statute of Monopolies (1623), which abolished all monopolies except those of inventors in their inventions.
The U.S. Constitution (Article 1, Section 8) authorizes Congress to enact patent legislation; the first such law was enacted Apr. 10, 1790. In 1836, Congress created the U.S. Patent Office (now the U.S. Patent and Trademark Office) and established the basic principles of American patent law. Comprehensive revision of that law occurred in 1870 and in 1952. In the United States any process or device may be patented if it is novel and useful and if plans and a working model are supplied. In all countries patents are valid for a limited term only (17 years in the United States); this limit ordinarily secures a profit to the inventor for a reasonable period yet will not permanently deprive the public of the free use of the invention.
The American law was designed to encourage the maximum inventiveness. Unlike many European countries where the rights to patents are limited so as to make innovations in industry easier, the United States does not require the patentee to permit the use of the invention on pain of losing the patent. Although there have been many independent inventors in the United States, most important patents today are the property of large corporations capable of exploiting them.
Injurious practices, such as withholding beneficial patents that might make obsolete some widely used product or process, have developed. Other practices, such as acquiring all patents in a given field and granting manufacturing licenses only to firms that promise to refrain from effective competition, have been repeatedly attacked by the federal government under the antitrust laws (see trust). Difficulties have also developed in the effective and equitable regulation of patents taken out by foreigners.
See F. L. Vaughan, The United States Patent System: Legal and Economic Conflicts in American Patent History (1956); B. W. Bugbee, Genesis of American Patent and Copyright Law (1967); C. MacLeod, Inventing the Industrial Revolution (1989).
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