A patent is a set of exclusive rights granted by a government to an inventor or applicant for a limited amount of time (normally maximum 20 years from the filing date, depending on extension).


The term "patent" originates from the Latin word patere which means to lay open (to public inspection) and the term letters patent, which originally denoted royal decrees granting exclusive rights to certain individuals or businesses.

Per the word's original definition, one theory of patent legislation is to induce the inventor to disclose knowledge for the advancement of society in exchange for a limited period of exclusivity. Since a patent grants the right to exclude others from practicing the invention, it would seem to give the owner a monopoly in the economic sense. This is however only true if there is no viable substitute product for the same market.

Also, ownership of a patent does not confer the right to actually make, use, or sell the invention, as practicing the invention may still infringe another patent ( e.g. the invention is an improvement of an existing invention patented by another), and other laws and regulations may apply. There is an ongoing debate about whether the benefits of patents outweigh the costs, particularly with respect to software patents and business method patents.

Rights granted and rights not granted

A modern patent provides the right to exclude others from making, using, selling, offering for sale, or importing the patented invention. Generally, patents are enforced only through civil lawsuits. Patent licensing agreements are effectively contracts in which the patent owner (the licensor) agrees not to sue the licensee for infringement of the licensor's patent rights. Governments typically reserve the right to suspend or cancel a patent at will.

A patent application, for a utility patent in the United States (as opposed to a design patent), must explain how to practice (i.e., make and/or use) the invention(s) and must also include claims that particularly point out the invention(s) and define the scope of the subject matter for which exclusive rights are sought by the patent applicant. Generally, the exclusive rights are limited to the subject matter encompassed by the patent's claims. Patent claims are typically of the form of a long sentence, e.g.:

  • " An apparatus for catching mice, comprising a base member for placement on a flat surface, a spring member... "
  • " A chemical for cleaning windows, comprising approximately 10-15% ammonia, ... "
  • " A method for computing future life expectancies, the method comprising gathering personal data including X, Y, Z, ... "

Each word of a claim is considered an "element" or "limitation" of the claim. In order to exclude someone from using your patented invention in a court, you will have to demonstrate to the court that what the other person is using is included within the scope of at least one claim of the patent.

For this reason, it is more valuable to obtain patent claims that include the absolute minimal set of limitations that differentiate a new invention over what came before. While the United States is moving towards more rigid claim interpretations, "equivalents" of claim elements or limitations may be permitted in determining patent infringement. The practice elsewhere in the world differs.


If an inventor takes an existing patented mouse trap design, adds a new feature to make an improved mouse trap, and obtains a patent on the improvement, he or she can legally build his or her improved mouse trap only with permission from the patent holder of the original mouse trap, assuming the original patent is still in force.

On the other hand, the owner of the improved mouse trap can exclude the original patent owner from using the improvement. Under these circumstances, patent owners sometimes engage in cross-licensing agreements.

Governing laws

At this time, there are a number of significant international treaties governing patent law. The most universal of these is the WTO TRIPs Agreement, to which almost all countries are a party. The United States, European Union, and Japan, are parties to all of the significant treaties. This has led to significant harmonization of patent law worldwide, particularly in the last decade of the 20th century and continuing into the 21st.

Despite recent harmonization, the United States patent laws are unique in several significant respects. The biggest difference is that, if two people apply for a patent on the same invention, the US system awards the patent to the "first to invent", whereas in the rest of the world the "first to file" is awarded the patent. A contest between different inventors over priority is called "interferences". Another unique aspect of US patent law is that an inventor has a one-year grace period after publication or sale to file a patent application, whereas in most other countries patent rights are lost if an application is not on file when a public disclosure, publication or sale takes place.

Patents are territorial in nature. Thus, patent protection in multiple countries requires separate filings of patent applications in each country, or region, where protection is sought. The Patent Cooperation Treaty (PCT), however, allows applicants to initially file a single international application, which later can be entered into separate countries or regions. Similarly, within Europe, a single patent application procedure is available through the European Patent Office , but successful applications result in multiple patents (up to 36) rather than a single European-wide patent. Such a European-wide unitary patent, or "community patent", has been the subject of discussion at the EU level since the 1970s, with no result so far.

Many of the international treaties are designed to afford some recognition of filing dates to patent applications previously filed in another country. In this respect, the most important treaty is the Paris Convention, dating back to 1883. Typically, inventors are allowed one year (the priority year) from the date of their filing in a first country to file the application in other countries.

The authority for patent statutes in different countries varies. In the United States, the Patent and Trademark Office gets its authority from statutes in Title 35 of the United States Code, which in turn is based on Article One, Section 8 of the U.S. Constitution.

Patent prosecution

Main article: patent prosecution .

Typically, an application for a patent is prepared by a professional patent agent or patent attorney and filed with a patent office where it is then examined by a patent examiner for patentability. The legal process of obtaining a patent from a patent office is called patent prosecution. Some countries do not formally review patent applications while others accept the judgment of other patent examining authorities. For example, some smaller countries, such as Belgium or the Netherlands grant a patent almost automatically or with minimal examination compared to what happens in the United States Patent and Trademark Office, the Japanese Patent Office, or the European Patent Office.

The patent prosecution process typically involves:

  1. Filing a patent application by inventor or applicant.
  2. Formalizing of application (signatures by inventors or applicant), often filed at the same time as the application.
  3. Establishing of a prior art search report by the patent office.
  4. Publication at 18 months from earliest claimed filing date. US applicants can request non-publication if the application is not filed outside the United States.
  5. Review by the examiner or the Examining Division, including communication with applicant to modify the claim language, if needed.
  6. Grant of the patent (if it the patentability criteria are met) and publication of the issued patent.
  7. Opposition period, during which anybody (e.g., other companies) can challenge the patent grant. This is not applicable for the US where other procedures are available, namely the reissue and reexamination procedure. In several countries, oppositions can be filed before the grant of the patent.

The specifics of the examination process include:

  1. Verifying that claims are for a patentable subject matter.
  2. Ensuring unity of invention, since each patent application can only be for one invention (called "restriction" practice in the United States).
  3. Formalities. Ensure that the drawings, description, and claims meet all formal requirements.
  4. Utility or industrial applicability.
  5. Novelty (newness)
  6. Non-obviousness or inventive step.

Different patent systems use different terms and different standards for these concepts, of which the most important probably are: patentable subject matter, novelty, non-obviousness and sufficient disclosure.

Patentable subject matter

The standard for what is patentable subject matter in the United States is "anything under the sun made by man" that is new (novel), useful, and non-obvious. Similar standards for patentability apply in Japan and the European Patent Office (EPO).

Under US law, a claimed invention is deemed useful if, at the time of filing, it is capable of providing some identifiable benefit (to a person of ordinary skill in the art of the invention). The benefit must be specific, substantial, and practical.

Generally speaking, there are three broad categories of patentable subject matter: processes, machines and articles of manufacture and use.

A process could be a method for making something, a method for using something, or a method for doing something. Processes include business methods, most software, medical techniques, sports techniques and the like. Machines include devices and apparatuses. Articles of manufacture include mechanical devices, electrical/electronic devices and compositions of matter such as chemicals, medicines, DNA, RNA, etc.

However, laws of nature, physical phenomena, and abstract ideas are not patentable. Software inventions implementing algorithms are not patentable for this reason unless it produces a "useful, concrete, and tangible result" (US law) or technical effect (European law). The US standard for the patentability of software is more liberal than that in Europe. Japanese patent law lies between the US and Europe.

The patentability of software (and business methods) is quite controversial from a global perspective. Case law in the United States permits patents for software and business methods. Yet computer programs as such are not patentable in Europe, although some inventions that use software can be patented in Europe.

Patents related to natural compounds (e.g. items found in rainforests) as well as medicines, medical treatment techniques, and genetic sequences are also controversial. There are significant country-by-country differences in handling these subject matters. For example, in the United States you can get a patent for a surgical method but you cannot enforce your right to exclude.


Main article: Novelty (patent)

Novelty relates to whether something existed before its invention by the applicant or was disclosed to the public before the patent application's filing date. For public disclosures of the invention by the inventor, the United States and Canada permit a one year grace period, but most other countries provide no grace period, instead requiring "absolute novelty".

An invention is not novel if there is a previously existing or disclosed device or process that includes all of the elements of the claimed invention. Identifying such "prior art" by the patent examiner is accomplished by a search of literature (technical journals, published patent applications and issued patents, etc.) that predate the filing date of the particular patent application.

Non-obviousness or inventive step

Main articles: Non-obviousness (patent)

Even if an applicant's claim for an invention is novel (i.e. not taught by a single prior art reference), a patent can still be denied to the applicant if the claimed subject matter would have been obvious to someone else skilled in the technical field of the invention. The purpose of forbidding patents on obvious technologies is to prevent a person from obtaining exclusive rights to what is effectively already in the possession of the public, even if documentation of the exact form of the applicant's embodiment happens to be lacking.

Accordingly, obviousness asks the question whether all previously known technology related to the invention would teach a "person having ordinary skill in the art", e.g. someone who does the type of things relating to the technical field of the invention, how to make the invention. Many patent applications in the United States, Europe and Japan are initially rejected as being obvious.

The standard of obviousness and its application are more subjective and controversial than that of novelty. If the requirements are set very high, virtually nothing is patentable. Similarly if the requirements are very low, all kinds of trivial inventions can receive patents.

Generally, the patent laws make it difficult for patent examiners to employ hindsight reasoning in rejecting a claim as obvious, by requiring some teaching that would motivate a person of ordinary skill in the art to modify the technology found in the prior to arrive at the claimed invention. In the United States, objective evidence or secondary considerations of non-obviousness can overcome a proper obviousness rejection. Such secondary considerations can include unexpected results, commercial success, long-felt need, failure of others, copying by others, licensing, and skepticism of experts.

As a practical matter, during examination the patent examiner will attempt to locate two or more references that when combined show all of the features of the claimed invention and indicate that one of ordinary skill would make that combination.

The threshold for the obviousness or inventive step standard can be particularly ambiguous in genus - species situations. For example, if an inventor finds two species of a particular genus, e.g. two particular chemical compositions out of 10,000 in the broader genus, should the inventor be entitled to a patent on the entire genus? Further, if someone has discovered the genus already, but not isolated any of the species, are the species obvious in light of the genus? Under US law, the species may still be patentable if they produce results that are unexpectedly different from those of other previously known members of the genus.

For example, suppose a software inventor unveils the quicksort sorting algorithm to the world but only discloses it using integers (this is the species). Can someone else then obtain a patent on an "improved" quicksort suitable for use on any partially ordered set (this is the genus)? Under US law, this is not a question of obviousness since a claim to the genus lacks novelty as the species is known.

Finally, in spite of all precautions, some patents still give a general impression of triviality. An example is given by the "combover" patent (U.S. Patent 4,022,227, filed December 1975 ), which has also been awarded the 2004 Ig Nobel Prize in engineering for its apparently unintentional ridiculousness.

Term of patent

As TRIPS agreement declares, the maximum term of an issued patent is twenty years from earliest claimed filing date. In the United States, for applications filed prior to June 8, 1995, the patent term is seventeen years from the issue date. For applications filed on or after June 8, 1995, the term is the longer of twenty years from the earliest claimed filing date, or seventeen years from the issue date. Under certain circumstances, principally undue delay caused by the United States Patent and Trademark Office, the term of a patent may be extended.

Also, in several countries there are multiple types of patents, and the twenty year term frequently only applies to utility patents and not design, petit, or other kinds of less heavily examined patents. For example, the term of a U.S. design patent, which protects the ornamental shape of objects, lasts fourteen years from its issue date.


If the better mousetrap patent is filed on January 1, 1996 and is issued or granted on January 1, 2000, it will lapse twenty years from filing: January 1, 2016. However, if the inventor comes up with a second improvement and claims priority to her first patent when filing the second patent on January 1, 1998, that second patent, after grant , would lapse twenty years from the earliest claimed priority: January 1, 2016.


While a patent grants an exclusive right on the invention claimed, many national laws provide for special rules on granting compulsory licence to requesting third parties when the invention is not put into to practice within a specified amount of time or is put into practice in a manner that is deemed to be insufficient for the needs of the Country. In practice, obtaining a compulsory licence is not easy.

Secrecy provisions are also present in many national laws in case the invention for which a patent is filed is deemed to have military interest.

A patent might also be seized by the State under grounds of public utility. For example, during the 2001 anthrax attacks, it was rumoured that the US was considering to seize from the Bayer Corporation the patent on the Cipro antibiotic. However, the anthrax attacks did not continue and the patent was not seized.

Early history of patents

Although there is evidence suggesting that something like patents was used among some ancient Greek cities, patents in the modern sense originated in Italy.

The first patent law was a Venetian Statute of 1474 in which the Republic of Venice issued a decree by which new and inventive devices, once they had been put into practice, had to be communicated to the Republic in order to obtain legal protection against potential infringers.

England followed with the Statute of Monopolies in 1623 under King James I of England.

Prior to this time, the crown would issue letters patent providing any person with a "monopoly" to produce particular goods or provide particular services. The first of them was granted by Henry VI in 1449 to a Flemish man a 20 year monopoly (co-incidentally, the current length of UK/EU patents is still 20 years) on the manufacture of stained glass (destined for Eton College).

This was the start of a long tradition by the English Crown of the granting of "letters patent" (meaning 'open letter', as opposed to a letter under seal) which granted "monopolies" to favoured persons (or people who were prepared to pay for them). This became increasingly open to abuse as the Crown granted patents in respect of all sorts of known goods (salt, for example).

This power, which was to raise money for the crown, was widely abused, and court began to limit the circumstances in which they could be granted: After public outcry, James I was forced to revoke all existing monopolies and declare that they were only to be used for 'projects of new invention'. This was incorporated into the Statute of Monopolies in which Parliament restricted the crown's power explicitly so that the King could only issue letters patents to the inventors or introducers of original inventions for a fixed number of years.

In the reign of Queen Anne the rules were changed again so that a written description of the article was given.

Section 6 of the Statute refers to "manner[s] of new manufacture... [by] inventors", and this section remains the foundation for patent law in New Zealand and Australia. The Statute of Monopolies was later developed by the courts to produce modern patent law; this innovation was soon adopted by other countries.

In the United Kingdom, the Patents Act 1977 harmonised UK patent law with the European Patent Convention. Consequently, UK patent law is no longer based on the Statute of Monopolies.

The Patent Commission of the U.S. was created in 1790. Its first three members were Secretary of State Thomas Jefferson, Secretary of War Henry Knox, and Attorney General Edmund Randolph.

On July 31, 1790 inventor Samuel Hopkins of Pittsford, Vermont became the first person to be issued a patent in the United States. His patented invention was an improvement in the "making of Pot Ash by a new apparatus & process". The earliest patent law required that a working model of each invention be produced in miniature.

The Patent Law was revised for the first time in 1793. It adopted a simple registration system where a patent would be granted for a $30 fee. The Patent Board was replaced by a clerk in the Department of State. James Madison, Secretary of State, created a separate Patent Office within the State Department and he appointed Dr. William Thornton as its first superintendent in May 1802.

On May 5th, 1809 Mary Dixon Kies became the first woman to be awarded a US patent. Later, in 1810, the Patent Office moved from the Department of State to Blodgetts Hotel. In the same year, they opened the patent model storage to the general public.

In 1834, the first black man granted a patent, Henry Blair (of Glenross, Maryland), patented a corn planter. In 1836, on August 31, Blair was issued a cotton seed planter patent. In 1842, George Bruce was awarded the first design patent for fonts. In 1863, Alfred Nobel gained a Swedish patent for the preparation of nitroglycerin (originally called " blasting oil "). In 1868, Nobel patented its safer-to-handle form dynamite.

The first 10,000 patents issued by the USPTO from July 1790 to July 1836 were perished in a fire in December 1836. About 2800 of them were later recovered. But the majority of them are still missing. The recovered patents are now called X-Patents because their patent numbers end with an "X."

Patent models

One of the most interesting early features of the U.S. patent system was the requirement of patent models. A patent model was a scratch-built miniature model no larger than 12" by 12" that showed how the patent works. Since most early inventors were ordinary people without technological or legal training, it was difficult for them to submit formal patent applications, due to the required small-scale models. However, to some degree, it was beneficial for these amateur inventors to submit a model. This is because their inventions might not be fully comprehended otherwise.

Patent models were required since 1790. The Congress of the U.S. abolished the legal requirement for them in 1870. The U.S. Patent Office kept this requirement until 1880. However, some inventors still willingly submitted models at the turn of the 20th century.


If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea, which an individual may exclusively possess as long as he keeps it to himself; but the moment it is divulged, it forces itself into the possession of everyone, and the receiver cannot dispossess himself of it. Its peculiar character, too, is that no one possesses the less, because every other possesses the whole of it. He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. That ideas should freely spread from one to another over the globe, for the moral and mutual instruction of man, and improvement of his condition, seems to have been peculiarly and benevolently designed by nature, when she made them, like fire, expansible over all space, without lessening their density at any point, and like the air in which we breathe, move, and have our physical being, incapable of confinement or exclusive appropriation. Inventions then cannot, in nature, be a subject of property. - Thomas Jefferson

Certainly an inventor ought to be allowed a right to the benefit of his invention for some certain time. Nobody wishes more than I do that ingenuity should receive liberal encouragement. In the arts, and especially in the mechanical arts, many ingenious improvements are made in consequence of the patent right giving exclusive use of them for fourteen years. -Thomas Jefferson

In the field of industrial patents in particular we shall have seriously to examine whether the award of a monopoly privilege is really the most appropriate and effective form of reward for the kind of risk bearing which investment in scientific research involves. - F.A. von Hayek , Individualism and Economic Order, 1948

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