Primary tabs

A patent grants the patent holder the exclusive right to exclude others from making, using, importing, and selling the patented innovation for a limited period. The U.S. Patent Act, 35 U.S.C. §§ 1 et seq., was enacted by Congress under its Constitutional grant of authority for inventors to secure the exclusive right to their discoveries for a limited time. See Article I, Section 8, Clause 8

Granting exclusive rights to the inventor is intended to encourage the investment of time and resources into the development of new and useful discoveries. In exchange for this limited monopoly, the U.S. Patent and Trademark Office (USPTO) requires immediate disclosure of the patented information. Once the term of protection has ended, the patented innovation enters the public domain.

Requirements for Patentability

The five primary requirements for patentability are: (1) patentable subject matter, (2) utility, (3) novelty, (4) nonobviousness, and (5) enablement.

Patentable Subject Matter

The patentable subject matter requirement addresses the issue of which types of inventions will be considered for patent protection. Under 35 U.S.C. § 101, the Code broadly defines categories for patentable subject matter as any process, machine, manufacture, or composition of matter or improvement thereof. In Diamond v. Chakrabarty 447 U.S. 303 (1980), the Supreme Court found that Congress intended patentable subject matter to "include anything under the sun that is made by man." However, the Court also stated that this broad definition has limits and does not embrace every discovery. According to the Court, the laws of nature, physical phenomena, and abstract ideas are not patentable. The relevant distinction between patentable and unpatentable subject matter is between products of nature, living or not, and human-made inventions.

The traditional rules stated that "printed matter" and "business methods" are unpatentable. Nonetheless, courts have called into question the traditional rule. In 1998, the Federal Circuit held that a system of conducting business can be patentable as a process even though it does not act on anything tangible. See State Street Bank & Trust Co. v. Signature Financial Group, 149 F.3d 1368 (Fed. Cir. 1998). The rule against patenting printed matter still retains its force. However, the printed matter may be patentable if its relationship with the physical invention is either new and useful or new and non-obvious.


The second requirement for patentability is that the invention be useful. See 35 U.S.C. § 101. The USPTO has developed guidelines for determining compliance with the utility requirement. The guidelines require that the utility asserted in the application be credible, specific, and substantial. The Utility Guidelines Training Materials defines these terms. Credible utility requires that logic and facts support the assertion of utility or that a person of ordinary skill in the art would accept that the disclosed invention is currently capable of the claimed use. The utility must be specific to the subject matter claimed and not a general utility that could apply to a broad class of inventions. The substantial utility requires that the invention have a defined real-world use; a claimed utility that requires or constitutes carrying out further research to identify or confirm use in the context of the real world is not sufficient.


The novelty requirement described under 35 U.S.C. § 102 consists of two distinct requirements: novelty and statutory bars to patentability. Novelty requires that the invention was not known or used by others in this country or patented or described in a printed publication in this or another country before the invention by the patent applicant. See 35 U.S.C. § 102(a). The invention must be new to meet the novelty requirement. The statutory bar refers to the fact that the patented material must not have been in public use or on sale in this country or patented or described in a printed publication in this or another country more than one year prior to the date of the application for a U.S. patent. See 35 U.S.C. § 102(b). In other words, the inventor may lose the right to a patent if the inventor delays too long before seeking patent protection. An essential difference between the novelty requirement and statutory bars is that an inventor's actions cannot destroy the novelty of his or her invention but can create a statutory bar to patentability.


Congress added the nonobviousness requirement to the test for patentability with the enactment of the Patent Act of 1952. The test for nonobviousness is whether the subject matter sought to be patented and the prior art is such that the subject matter as a whole would have been obvious to a person having ordinary skill in the art at the time of the invention. See 35 U.S.C. § 103.

The Supreme Court first applied the nonobviousness requirement in Graham v. John Deere Co., 383 U.S. 1 (1966). The Court held that the Court determines nonobviousness through basic factual inquiries into the scope and content of the prior art, the differences between the prior art and the claims at issue, and the level of skill possessed by a practitioner of the relevant art.

In 2007, the Supreme Court again addressed the test for nonobviousness. See KSR International Co. v. Teleflex, Inc. (04-1350). In KSR, the Court rejected the test for nonobviousness employed by the Court of Appeals for the Federal Circuit as being too rigid. Under the "teaching, suggestion, or motivation test" applied by the Federal Circuit, a patent claim is obvious only if "some motivation or suggestion to combine the prior art teachings can be found in the prior art, the nature of the problem, or the knowledge of a person having ordinary skill in the art." The Court endorsed a more expansive and flexible approach. The approach states that the Court examines whether the improvement is more than the predictable use of previous art elements according to the established functions.


The enablement requirement is directly related to the specification or disclosure. Every patent application must include the specification/disclosure. "The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention." See 35 U.S.C. § 112. At the end of the specification, the applicant lists "one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention." See 35 U.S.C. § 112. Enablement encompasses three distinct requirements: the enablement requirement, the written description requirement, and the best mode requirement.   

Every patent application must include a specification describing the workings of the invention and one or more claims at the end of the specification stating the precise legal definition of the invention. The specification must describe the invention with sufficient particularity that a person with ordinary skill in the art would be able to make and use the claimed invention without "undue experimentation" to satisfy the enablement requirement. See In re Wands, 858 F.2d 731 (Fed Cir. 1988). In In re Wands, the Federal Circuit Court of Appeals listed eight factors to consider in determining whether a disclosure would require undue experimentation. The United States Patent and Trademark Office has incorporated these factors in the Manual of Patent Examining Procedure (MPEP 2164.01(a)).

The written description requirement compares the description of the invention set out in the specification with the particular attributes of the invention identified for protection in the claims. It is possible for a specification to meet the test for enablement but fail the written description test. The basic standard for the written description test is that the applicant must show he or she was "in possession" of the invention as later claimed at the time of the application filing. A written description of the specification must support any claim by the inventor. The goal of drafting patent claims is to make them as broad as the USPTO will allow. The writing requirement imposes two important limitations: the applicant may not seek protection for a claim broader than the supporting specification. If the applicant intends to focus on a particular attribute of the invention in the claims, the applicant must clearly indicate that attribute in the specification.

In addition to disclosing sufficient information to enable others to practice the claimed invention, the patent applicant must disclose the best mode of practicing the invention. See 35 U.S.C. § 112. The inventor violates the best mode requirement where the inventor fails to disclose a preferred embodiment or fails to disclose a preference that materially affects making or using the invention. See Bayer AG v. Schein Pharmaceuticals, Inc., 301 F.3d 1306 (Fed. Cir. 2002). A violation of the best mode requirement involves two essential elements: first, whether the inventor actually had a preferred mode of practicing the invention at the time of the application filing. Suppose that the inventor did contemplate the best mode for practicing the invention. Then, the question becomes whether there was sufficient disclosure of information to enable a person of ordinary skill in the art to practice the best mode of the invention.

Types of Patents

There are six types of patents that the United States Patent and Trademark Office has created (the utility patent and the design patent are the most common):

  • Utility Patent
    • Issued for the invention of a new and useful process, machine, manufacture, or composition of matter, or a new and useful improvement thereof, it generally permits its owner to exclude others from using or selling the invention for a period of up to twenty years from the date of patent application filing, subject to the payment of maintenance fees. Approximately 90% of the patent documents issued in recent years have been utility patents, also referred to as "patents for invention."
  • Design Patent
    • Issued for a new, original, and ornamental design embodied in or applied to an article of manufacture, it permits its owner to exclude others from making, using, or selling the design. Design patents issued from applications filed on or after May 13, 2015, shall be granted for a term of fifteen years from the date of grant. Design patents issued from applications filed before May 13, 2015, shall be granted for a term of fourteen years from the date of grant. Design patents are not subject to the payment of maintenance fees.
  • Plant Patent
    • Issued for a new and distinct, invented or discovered asexually reproduced plant, including cultivated sports, mutants, hybrids, and newly found, other than a tuber propagated plant or a found in an uncultivated state, it permits its owner to exclude others from making, using, or selling the plant for a period of up to twenty years from the date of patent application filing.  Plant patents are not subject to the payment of maintenance fees.
  • Reissue Patent
    • Issued to correct an error in an already issued utility, design, or plant patent, it does not affect the period of protection offered by the patent. However, the scope of patent protection can change as a result of the reissue patent. 
  • Defensive Publication (DEF)
    • Issued instead of a regular utility, design, or plant patent, it offers limited protection, defensive in nature, to prevent patent violation of an invention, design, or plant. The Statutory Invention Registration replaced the Defensive Publication in 1985-86.
  • Statutory Invention Registration (SIR)
    • This document replaced the Defensive Publication in 1985-86 and offered similar protection. Please note that the America Invents Act (AIA), enacted on September 16, 2011, repeals provisions about statutory invention registrations and the discontinuation of the issues of these documents.

Patents Created With Federal Funding

Prior to the Bayh-Dole Act passage in 1980, if someone created an invention with the help of federal funding, then the patent for that invention would be assigned to the federal government. The Act allows for the patents of federally-funded inventions to be assigned to universities, small businesses, and non-profits if the creation of the invention occurred when the inventor was a member of that institution (i.e., Inventor X was a student at University Y while Inventor X created the product. The patent would then be assigned to University Y, rather than to the federal government). 

Patent Application Process

Patents are granted and issued through the United States Patent and Trademark Office (USPTO). See 35 U.S.C. §§ 1-26. The rules of practice in patent cases are in Title 37, Part I, of the Code of Federal Regulations. The "prosecution" is a process where the USPTO grants a patent. A prosecution begins when an inventor files the patent application with the USPTO. The basic elements of a patent application are:

  • The technical specifications, including a summary of the invention, usually accompanied by drawings
  • One or more claims listed at the end of the specification
  • An oath or declaration that the inventor was the first to invent the subject matter described in the specification
  • Applicable filing fees

The patent examiner goes over each patent application received by the USPTO in the order it is received. The patent examiner must thoroughly study the patent application and investigate the prior arts. See 37 C.F.R. § 1.104. Once the examination is complete, the examiner may accept the application and issue a patent, issue a rejection of some or all of the claims made in the application, or issue an objection if a problem with the form of the application is detected. If the USPTO rejects a claim as unpatentable or an objection to the application form is issued, the examiner must notify the applicant. The examiner must state the reasons for each rejection or objection and provide information and references to assist the applicant in judging the propriety of continuing the prosecution. See 37 C.F.R. § 1.10435 U.S.C. § 132.

Upon receiving notice of any objections or rejections issued by the USPTO, the applicant is entitled to a reexamination of the application, whether or not the inventor has amended the application to address the reasons stated by the examiner. See 35 U.S.C. § 132. If the inventor receives a second or final rejection of the application, the applicant may file an appeal of the decision with the Board of Patent Appeals and Interferences. See 35 U.S.C. § 134. An applicant dissatisfied with the decision of the Board of Patent Appeals and Interferences has a choice between two further options for appeal. The applicant may either appeal the Board's decision to the United States Court of Appeals for the Federal Circuit under 35 U.S.C. § 141 or pursue a civil action to obtain a patent under 35 U.S.C. § 145 by filing against the Director in the United States District Court for the District of Columbia. 

Amendments to the Patent Act to accommodate the Patent Cooperation Treaty (PCT) took place in 1975. See 35 U.S.C. §§ 351-376. The PCT permits applicants from signatory countries to wait up to 30 months after the initial filing of a patent application in one country before beginning a full prosecution of the patent in other countries. The PCT gives the inventor the benefit of extra time to assess the technical merits and commercial potential of the invention and to decide in which countries the inventor will seek patent protection before the expenditure of filing and examination fees.

Rights of a Patent Owner

The patent owner obtains the exclusive right to prevent others from making, using, offering for sale, or selling the patented invention (see 35 U.S.C. § 154). Before the Agreement on Trade-Related Aspects of Intellectual Property (TRIPS) accompanying the Uruguay Round GATT, patents were issued for a non-renewable period of seventeen years, measured from the date of issuance. Under current statutory provisions, the term of protection for utility patents is twenty years measured from the date of filing (35 U.S.C. § 154), with extensions of up to five years permitted for drugs, medical devices, and additives (35 U.S.C. § 156). The current term of protection for design patents is fourteen years from the date of filing. See 35 U.S.C. § 173

A long-established doctrine of patent law, the exhaustion doctrine, entitles a patentee to a single royalty per patented device. This rule aims to prevent patentees from collecting a series of royalty payments for a single invention. The Supreme Court affirmed this rule in its 1942 decision, United States v. Univis Lens Co., 316 U.S. 241. In 2008, the U.S. Supreme Court reconsidered the contemporary relevance of the doctrine in Quanta Computers v. LG Electronics (06-937). In a unanimous decision, the Court reaffirmed the doctrine, holding that the exhaustion doctrine prevents a patentee from bringing an action against a third-party purchaser after having already received a royalty payment from the initial sale.


Federal law exclusively governs patents. The federal district courts have original jurisdiction of all civil cases arising under any federal law relating to patents. See 28 U.S.C. § 1338. In 1982, the United States Court of Appeals for the Federal Circuit assumed the jurisdiction of the former U.S. Court of Patent and Customs Appeals. The Federal Circuit now reviews the appeals from district court decisions related to patent law.

Patent Infringement - General

Once the USPTO grants the patent, the patent owner may bring a lawsuit against anyone accused of infringing the patent. There are two primary defenses to patent infringement: the patent is invalid, and even if the patent is valid, the products being made or sold do not infringe the patent. The Patent Act provides that an issued patent is presumed valid, and the burden of establishing that a patent is invalid rests with the person asserting its invalidity. See 35 U.S.C. § 282. Independent invention is not a defense against patent infringement. A person who reasonably fears being sued for patent infringement may file a lawsuit for a declaratory judgment that the patent at issue is invalid or that the conduct in question does not constitute infringement.

In 2007, the U.S. Supreme Court in MedImmune v. Genentech (05-608) held that a patent licensee does not have to breach the terms of the contract in order to meet the actual controversy requirement and challenge the licensed patent in court.

Patent Infringement - Venue

In TC Heartland LLC v. Kraft Food Group Brands LLC (2016), the Supreme Court tightened the limits on where a patent holder can file patent lawsuits. Prior to this ruling, companies suing for patent infringement often sued in the Federal Eastern District of Texas. The courts in that district found for the plaintiffs in roughly 80% of cases. However, the court found that "patent law sensibly requires that the defendant either be incorporated in the state in which the case is filed or have a regular place of business there." 

As such, the venue is proper patent infringement cases only when one of two requirements is met: 

  • “[a]ny civil action for patent infringement may be brought in the judicial district where the defendant resides,” or
  • “where the defendant has committed acts of infringement and has a regular and established place of business.” 

Further, for the first requirement, the Supreme Court clarified—according to the §1400(b) Patent Venue Statute—that residence refers only to the State of incorporation.

Patent Infringement - Reselling Products

In Impression Products, Inc. v. Lexmark International, Inc. (2017), the Supreme Court held that when a patented item is sold (in this case, ink cartridges for printers), the patent holder cannot sue for patent infringement over the fact that the alleged violator is reselling the item. Once the patent holder sells the patented item, the patent holder relinquishes the patent rights to that item, even if the item is being resold. The patent holder relinquishes the patent rights to the item even if the patent holder and the initial buyer signed a contract explicitly stating that the patent holder would retain the patent rights for that item. Here, the Court decided to bolster its support of the exhaustion doctrine.

Remedies for Patent Infringement

35 U.S. Code Chapter 29 governs remedies for patent infringements.

Attorney Fees

35 U.S. Code Chapter 29 Section 285 governs attorney fees. The statute reads: "The court in exceptional cases may award reasonable attorney fees to the prevailing party." Lower courts have historically struggled with interpreting "exceptional cases." The Supreme Court, however, gave some clarity to the issue in Octane Fitness, LLC v. ICON Health & Fitness, Inc., 134 S. Ct. 1749 (2014), making this case stand out in the jurisprudence surrounding the awarding of attorney fees in patent infringement cases.  

The Octane Court defined an "exceptional case" as one that stands out due to either one of two things:

  • The strength of a party’s litigating position
    • For this prong, courts should look at the facts of the case and the law that governs the issue
  • The case is litigated in an unreasonable manner
    • To determine whether a case is ‘exceptional,’ lower courts should look at the totality of the circumstances on a case-by-case basis 

For more, see this George Washington University Law Review note.

[Last updated in January of 2024 by the Wex Definitions Team]