A patent for an invention is the grant of a property right to the inventor, issued by the United States Patent and Trademark Office. Generally, the term of a new patent is 20 years from the date on which the application for the patent was filed in the United States or, in special cases, from the date an earlier related application was filed, subject to the payment of maintenance fees. U.S. patent grants are effective only within the United States, U.S. territories, and U.S. possessions. Under certain circumstances, patent term extensions or adjustments may be available.

The right conferred by the patent grant is, in the language of the statute and of the grant itself, “the right to exclude others from making, using, offering for sale, or selling” the invention in the United States or “importing” the invention into the United States. What is granted is not the right to make, use, offer for sale, sell, or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention. Once a patent is issued, the patentee must enforce the patent without aid of the USPTO.

There are three types of patents: (1) utility patents; (2) design patents; and (3) plant patents.

The Constitution of the United States gives Congress the power to enact laws relating to patents, in Article I, section 8, which reads "Congress shall have 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." Under this power Congress has from time to time enacted various laws relating to patents. The first patent law was enacted in 1790. The patent laws underwent a general revision which was enacted July 19, 1952, and which came into effect January 1, 1953. It is codified in Title 35, United States Code. Additionally, on November 29, 1999, Congress enacted the American Inventors Protection Act of 1999 (AIPA), which further revised the patent laws.

The patent law specifies the subject matter for which a patent may be obtained and the conditions for patentability. The law establishes the United States Patent and Trademark Office to administer the law relating to the granting of patents and contains various other provisions relating to patents.

In Pennsylvania, as in all states, patents are governed by federal law, specifically Title 35 of the United States Code. The United States Patent and Trademark Office (USPTO) is the federal agency responsible for granting patents to inventors. Patents provide a property right to the inventor, typically lasting for 20 years from the application filing date, which gives them the exclusive right to exclude others from making, using, selling, or importing the patented invention in the U.S. There are three types of patents: utility, design, and plant patents. The patent system is designed to encourage innovation by providing inventors with a limited-time monopoly in exchange for public disclosure of their invention. The American Inventors Protection Act of 1999 is one of the latest significant revisions to patent law. Patentees are responsible for enforcing their own patents, as the USPTO does not assist in enforcement. Extensions or adjustments to the patent term may be available under certain circumstances.