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United States[]


The U.S. Constitution authorizes Congress

[t]o promote the Progress of Science and useful Arts, by securing for limited Times to . . . Inventors the exclusive Right to their respective . . . Discoveries.[1]

The U.S. patent system is based on federal statutes and administered exclusively by federal institutions.

Congress enacted the first patent law in 1790, declaring that anyone who had "invented or discovered any useful art, manufacture, engine, machine, or device, or any improvement therein not before known or used" shall have "the sole and exclusive right and liberty of making, constructing, using and vending to others to be used" for a term not to exceed fourteen years. Although revised by Congress on several occasions over the next two centuries, this rather terse formulation has remained the core of the patent system. The Patent Act of 1952,[2] is the most recent patent statute.

That the Constitution places limits on congressional authority in patent matters was made clear in Graham v. John Deere Co.[3]:

The clause is both a grant of power and a limitation. This qualified authority . . . is limited to the promotion of advances in the "useful arts." . . . The Congress in the exercise of the patent power may not overreach the restraints imposed by the stated constitutional purpose. Nor may it enlarge the patent monopoly without regard to the innovation, advancement or social benefits gained thereby. Moreover, Congress may not authorize the issuance of patents whose effects are to remove existent knowledge from the public domain, or to restrict free access to materials already available. Innovation advancement, and things which add to the sum of useful knowledge are inherent requisites in a patent system which by constitutional command must "promote the Progress of . . . the useful Arts."[4]

The U.S. patent statute is the foundation of the U.S. patent system, but statutory language is an inadequate guide to the "law" of patents, most of which has developed through the judicial and administrative institutions responsible for applying the statutes. Patent law is comprised of the relevant statutes, interpretations of those statutes and their predecessors by the federal courts, and the regulations and practices of the Patent Office.

The primary goal of the patent system is to encourage innovation and commercialization of technological advances. To this end, the patent system offers an incentive to inventors to publicly disclose their inventions in exchange for the exclusive right to prevent others from making, using, offering for sale or selling the inventions throughout the United States or importing the inventions into the United States.

Patent policy serves to benefit the public. "The basic quid pro quo contemplated by the Constitution and the Congress for granting a patent monopoly is the benefit derived by the public from an invention with substantial utility."[5] The public disclosure of scientific and technical information is part of the consideration that the inventor gives the public.

The patent system serves as an important complement to the copyright system for computer and software innovations by providing protection for the functional aspects of these innovations. Unlike copyright protection which attaches automatically at the moment of fixation, an inventor must specifically request protection by filing a application and establish that the invention meets all of the statutory requirements of patentability. Rights are obtained by filing a patent application with the Patent and Trademark Office (PTO), and proceeding through an examination process.

Patentable subject matter[]

Patent protection is available for inventions without differentiation as to the field of technology: "any new and useful process, machine, manufacture, or composition of matter" can be patented.[6] This language has been interpreted broadly by the Supreme Court in Diamond v. Chakrabarty,[7], wherein the Court held:

The subject-matter provisions of the patent law have been cast in broad terms to fulfill the constitutional and statutory goal of promoting "the Progress of Science and the useful Arts". . . . Congress employed broad general language in drafting [Section] 101 precisely because such inventions are often unforeseeable. Judicial precedent does exist denying patentability under Section 101 for claims directed to laws of nature and methods of doing business.[8]

Despite this breadth, certain limits do exist on what can be patented. For example, a person cannot patent a process that consists exclusively of the steps one would follow to apply a mathematical principle to solve a mathematical problem.[9]

This restriction is not statutory; instead, it arises from judicial interpretation of the law governing patentable categories of invention, and is based on the notion that one cannot preempt use of laws of nature or mathematical truths. Similarly, one cannot patent an arrangement of information or a writing, as such things do not fall within one of the enumerated categories of inventions eligible to be patented.[10]

Patentability requirements[]

Once it is determined that an applicant has requested protection for subject matter that is eligible to be patented, the examination process shifts to evaluate the substantive merits of the invention. To obtain a patent, an invention (that is, a product, process, machine, or composition of matter)[11] must be novel,[12] nonobvious,[13] and useful.[14] Moreover, a patentee must disclose the invention clearly enough so that one skilled in that art can make and use it without undertaking a great deal of experimentation;[15] must highlight or describe what the inventor claims so that others can easily discern the boundaries of the patent;[16] and must tell the public the inventor's "best mode" — most effective method — for practicing the invention.[17]

The patentability requirements for novelty and nonobviousness "are grounded in the notion that concepts within the public grasp, or those so obvious that they readily could be, are the tools of creation available to all."[18] Thus, patent policy recognizes that certain limits on patents are necessary to avoid unnecessarily restraining competition.[19]

The PTO performs this evaluation by comparing the invention undergoing examination to the "prior art." Generally speaking, prior art includes information that is publicly available prior to the filing date of a application.[20]


An invention satisfies the novelty requirement if it differs in any material way from what is known in the "prior art."

Novelty exists unless a single prior art reference completely discloses the invention that is claimed by the applicant. For example, if a application is filed two years after an article is published in a technical journal which completely discloses the invention claimed in the application, the application will be rejected by the PTO on the grounds that the claimed invention lacks novelty over that printed publication through operation of 35 U.S.C. §102(b).


An invention satisfies the nonobviousness requirement if a "person of ordinary skill in the art" would not have viewed the invention as having been obvious in view of the prior art at the time the invention was made.[21] Some flexibility is provided to applicants in the United States regarding when they must seek protection to avoid losing patent rights due to prior public disclosure of the invention.[22]

Adequate disclosure[]

An applicant must also satisfy a number of requirements that govern the contents and form of a application. A application consists of a specification and claims. The claims of a patent define the metes and bounds of the invention by specifically defining the features of an invention which are protected. Among other things, Section 112 requires that the inventor provide an adequate disclosure of the invention that the applicant has claimed.[23] A disclosure is adequate when it enables a person of ordinary skill to "practice" the invention as claimed without undue experimentation or effort. Section 112 also requires that the inventor disclose the "best mode" of practicing the invention known to him. The requirements of Section 112 serve to ensure that the patent provides a high-quality, technically accurate disclosure of the invention.

Once issued, a patent grants its owner the exclusive right to prevent others from making, using, offering for sale, or selling the claimed invention in the United States, or importing the claimed invention into the United States.[24] If the PTO determines that all the patentability requirements have been met for the invention for which patent protection is requested, a patent will be granted to the applicant.

Patent duration[]

A owner is given a term of protection that begins on the date the patent is granted and ends 20 years from the date the application leading to the patent was filed.[25] By limiting the duration of a patent, "[t]he Patent Clause itself reflects a balance between the need to encourage innovation and the avoidance of monopolies which stifle competition without any concomitant advance in the 'Progress of Science and useful Arts."[26]

Patent infringement[]

The patent owner may assert these rights against a party that performs any of the acts that would infringement the patent. Patent owners who wish to compel others to respect their rights must commence enforcement proceedings, which most commonly consist of litigation in the federal courts. Although issued patents enjoy a presumption of validity, the patent owner has the initial burden of proving that the accused party infringed one or more of the patent claims.[27]

Infringement is established by demonstrating that the accused party has made, used, sold, imported or offered to sell a product that falls within the scope of a product patent claim.[28]

If a patent has been granted on a process, the patent owner must show that the accused party engaged in activity that would infringe the process claims, or that the accused party made, used, sold, offered to sell or imported a product produced using the claimed process.[29] A patent owner's failure to promptly enforce its rights once an infringement is discovered can limit his or her remedies or may even preclude enforcement against that party.

There are two forms of infringement, literal infringement and infringement through operation of the "doctrine of equivalents." Literal infringement means that the accused product or process contains each and every element set forth in the patent claims. infringement through the "doctrine of equivalents" refers to a situation where the accused product or process does not have each of the elements set forth in the claims but the accused product or process "performs substantially the same function in substantially the same way to obtain the same result as the patented invention." The latter form of infringement is intended to address situations where an accused infringer has made insubstantial changes to a product to avoid liability for infringement.

There are no criminal — only civil — penalties for committing patent infringement. However, there are some criminal and quasi-criminal penalties for certain conduct related to patents.

The Court of Appeals for the Federal Circuit (Federal Circuit) possesses nationwide jurisdiction over most patent appeals from the district courts.[30] The U.S. Supreme Court enjoys discretionary authority to review cases decided by the Federal Circuit.[31]

Defenses to infringement claims[]

A party accused of infringement can avoid liability by asserting that the patent does not cover the accused product or process. The accused infringer can also assert that one or more of the patent claims is invalid. This is most often accomplished by submitting new prior art which was not considered by the PTO in the examination of the application. The accused infringer will typically argue that the new information anticipates or makes obvious the claimed invention. While the statute provides that all claims of a patent are presumed valid, the disclosure of new information that was not considered by the PTO can have significant repercussions when these claims are considered by a court.

The party may also show that the claims are defective in view of Section 112 because they are broader than what is actually supported by the disclosure, or that the patent as a whole is unenforceable.

A party can also preclude the enforcement of a patent without specifically addressing the validity of the patent. This can occur, for example, if the patent owner engaged in "inequitable conduct" before the PTO (e.g., the inventor withheld material prior art from the PTO or made other misrepresentations intended to mislead the PTO), or misused its patent rights (e.g., in an antitrust context). In both instances, the patent will be unenforceable against any and all infringers, even if the patent satisfies all patentability requirements.</ref> Every claim in a patent, however, is presumed valid.[32]

Thus, in district court, the party challenging patent validity must demonstrate through clear and convincing evidence that the patent fails to satisfy one or more of the statutory criteria of patentability (e.g., novelty, utility, nonobviousness), or that the application is defective because it has an inadequate disclosure.[33]


  1. U.S. Const., art. I, §8, cl. 8.
  2. 35 U.S.C. §1 et seq.
  3. 383 U.S. 1, 148 U.S.P.Q. (BNA) 459 (1966) (full-text).
  4. Id. at 5-6, 148 U.S.P.Q. (BNA) at 462. See also Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489 U.S. 141, 146 (1989) (full-text) ("The Patent Clause itself reflects a balance between the need to encourage innovation and the avoidance of monopolies which stifle competition without any concomitant advance in the 'Progress of Science and useful Arts.'").
  5. Brenner v. Manson, 383 U.S. 519, 534-35 (1966) (full-texxt). The consideration an inventor gives in return for a patent "is the benefit which he confers upon the public placing in their hands a means through the use of which their wants may be supplied." 1 William Robinson, The Law of Patents for Useful Inventions §22, at 305 (1890).
  6. See 35 U.S.C. §101.
  7. 447 U.S. 303, 309 (1980) (full-text).
  8. Parker v. Flook, 437 U.S. 584, 589 (1978) (full-text).
  9. See Diamond v. Diehr, 450 U.S. 175, 185 (1981) ("[e]xcluded from such patent protection are laws of nature, natural phenomena, and abstract ideas"); Chakrabarty, at 309 ("new mineral discovered in the earth or a new plant found in the wild is not patentable subject matter. Likewise, Einstein could not patent his celebrated law that E=mc2; nor could Newton have patented the law of gravity. Such discoveries are 'manifestations of . . . nature, free to all men and reserved exclusively to none.'"); Gottschalk v. Benson, 409 U.S. 63, 72 (1973) ("the patent would wholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itself"); In re Alappat, 33 F.3d 1526, 1542 (Fed. Cir. 1994) (noting that the Supreme Court did not intend to make mathematical algorithms a fourth category of unpatentable subject matter along with Diehr's holding that laws of nature, natural phenomena and abstract ideas, but rather that some types of mathematical subject matter standing alone are only abstract ideas).
  10. See In re Gulack, 703 F.2d 1381, 1385 (Fed. Cir. 1983) ("[w]here the printed matter is not functionally related to the substrate, the printed matter will not distinguish the invention from the prior art in terms of patentability").
  11. 35 U.S.C. §101.
  12. Id. §102.
  13. Id. §103.
  14. Id. §101.
  15. Id. §112; J.E.M. Ag Supply, Inc. v. Pioneer Hi-Bred Int'l, Inc., 534 U.S. 124, 142 (2001) (“The disclosure required by the Patent Act is the 'quid pro quo of the right to exclude'" (internal citations omitted)).
  16. Id.
  17. Id.
  18. Id. at 156.
  19. See, e.g., Harmon, Patents and the Federal Circuit §1.2, at 12 ("It should not be supposed, however, that there are no public costs associated with the right to exclude. These include inflated prices (invariably absorbed by the consumer), which frequently accompany exclusive rights, and overinvestment. The patent system seeks to maintain an efficient balance between incentives to create and commercialize and the public costs engendered by these incentives." (Footnotes omitted)).
  20. 35 U.S.C. §102 defines the different categories of prior art to include patents issued prior to the applicant's filing date by the United States or by other countries, patents issued by the United States after but filed prior to the applicant's filing date, printed publications distributed in the United States or abroad, evidence of public use or public disclosure of the claimed invention in the United States more than one year before the applicant's filing date, and evidence of a sale or an offer to sell the claimed invention in the United States more than one year prior to applicant's filing date.
  21. 35 U.S.C. §103.
  22. Under U.S. law, an inventor may rely on a "grace period" to avoid the otherwise patent-defeating effect of an earlier public disclosure of his or her invention. For example, an inventor may be able to obtain a patent on an invention that was disclosed in a technical journal provided she can establish that she conceived of the invention prior to that disclosure. There is a statutory limit of one year imposed by Section 102(b) on the grace period. This grace period is not available in all countries. As a result, applicants must exercise care before disclosing their invention to avoid forfeiting patent rights in countries other than the United States.
  23. Every patent concludes with one or more claims that outline the boundaries of the rights granted by the government to the patentee. Claims must be commensurate in scope with the disclosure of the applicant, and must be clear and understandable.
  24. See 35 U.S.C. §154(a)(1), as amended by Uruguay Round Agreements Act, Pub. L. 103-465, 1994 U.S.C.C.A.N. (108 Stat.) 4809, 4984.
  25. 35 U.S.C. §154(a)(2). Although the patent term is based upon the filing date, the patentee obtains no enforceable legal rights until the USPTO allows the application to issue as a granted patent. A number of Patent Act provisions may modify the basic 20-year term, including examination delays at the USPTO and delays in obtaining marketing approval for the patented invention from other federal agencies. The term of patents was changed as part of the Uruguay Round Agreements Act, Pub. L. 103-465, 1994 U.S.C.C.A.N. (108 Stat.) 4809, 4984. Under the former system, patent rights would begin on the date a patent was granted and would end 17 years later. As part of the transition to the new system, the term of patents that were pending on June 8, 1995, or which result from applications pending on that date, will begin on the date the patent was granted and will end on the date that is the later of 17 years from the date of grant or 20 years from the earliest effective filing date of the application leading to the patent.
  26. Bonita Boats, Inc. v. ThunderCraft Boats, Inc., 489 U.S. 141, 146 (1989) (full-text).
  27. See 35 U.S.C. §271.
  28. See 35 U.S.C. §271(a), as amended by Uruguay Round Agreements Act, Pub. L. No. 103-465, 1994 U.S.C.C.A.N. (108 Stat.) 4809, 4984.
  29. The United States allows the holder of a U.S. patent on a process to enforce its rights against a third party that uses a process patented in the United States outside the territorial boundaries of the United States and then attempts to import a product produced using that patented process.See 35 U.S.C. §295.
  30. 28 U.S.C. §1295(a)(1).
  31. Id. §1254(1).
  32. See 35 U.S.C. §282.
  33. A party can also challenge the validity of a patent in a reexamination proceeding before the Patent and Trademark Office. In such a proceeding, however, the basis for challenge is limited to novelty and obviousness in view of only certain types of prior art, namely, printed publications and patents.

See also[]