One form of intellectual property, a patent is a set of exclusive rights granted by a government to an inventor or applicant for a limited amount of time (normally 20 years). The term "patent" originates from the term to patent 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 widely accepted social goal of patents is to induce the inventor to disclose knowledge for the advancement of society in exchange for a limited period of exclusivity.

Table of contents
1 Rights granted and rights not granted
2 Governing laws
3 Examination process and procedure
4 Term of patent
5 Early history of patents
6 Quote
7 Patent Discussion
8 Patent Resources

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 private actions; namely, through civil lawsuitss or licensing agreements. Governments typically reserve the right to suspend or cancel a patent at will.

An application for a patent (other than 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). Generally, the exclusive rights are limited to the invention(s) defined 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 comprised of 10-15% ammonia, ...", "A method for computing future life expectancies, the method comprising gathering personal data including X,Y, Z, ...", etc.

Claim language formats and practices vary widely between different countries. Each word of a claim is considered an "element" of the claim. In order to exclude someone from using your invention in a court you will have to demonstrate to the court that what the other person is using is identical to the claimed invention. (Note, while the United States is moving towards more rigid claim interpretations and generally, issued patents have a large number of claims, the practice elsewhere in the world differs.)


If an inventor takes an existing patented mouse trap design, modifies it 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 owner of the original mouse trap, assuming the original patent is still in force. However, if the original patent owner tried to copy the inventor's improvement, he or she could sue that original patent owner to exclude him or her from using the improvement without permission.

Continuing the example though, if the inventor's improved mouse trap patent claims a guillotining member, but the original manufacturer copies other unclaimed aspects of the improvement, the inventor might not be able to exclude the manufacturer from using those other improvements.

For this reason, it is important, especially in the United States, that the patentee eventually obtain patent claims that include the absolute minimal set of items that differentiate a new invention over what came before. Dependent claims can be used to describe additional variations and features.

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 lead to significant harmonization of patent law worldwide, particularly in the last decade of the 20th century and continuing into the 21st.

Procedurally, the United States system is perhaps one of the more unusual although some recent changes have brought the United States' system further into line with other major patent systems. The biggest difference that remains is that the US system awards the patent to the "first to invent", yet in the rest of the world the "first to file" is awarded the patent. In contests between different inventors over priority (called "interferences"), however, the second one to file has the burden of proof and usually loses such contests.

Patent grants are territorial in nature. Thus, patent protection in multiple countries require separate filings of patent applications in each country, or region, where protection is sought. Within Europe, a single patent application procedure is available through the European Patent Office, but successfuls applications result in multiple patents rather than a single European-wide patent.

Many of the international treaties are designed to afford some recognition of filing dates to patent applications filed in one country. Typically, inventors are allowed one year from the date of their filing in their home country to file the application abroad, frequently called national stage filing. Systems such as the Patent Cooperation Treaty (or PCT) allow inventors a cost effective way to further delay national stage filings.

The authority for patent statutes in different countries varies. In the United States, the Patent and Trademark Office gets its authority from Article One, Section 8 of the U.S. Constitution. In other countries, the origin may be a statute or other law or rule.

Examination process and procedure

Typically, an application for a patent is examined before a patent is issued or granted for an invention. That is to say, the application is reviewed by a patent examiner for patentability.

Some countries do not formally review patents and others will accept the judgment of other patent examining authorities. For example, some smaller countries, such as Belgium, will grant a patent automatically or with minimal examination if a patent has been granted on the same invention in the United States, European Union, or Japan.

A typical examining procedure is:

  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. Initial 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.
  4. Review by Examiner, including back and forth negotiation with applicant to narrow/modify the claim language.
  5. Publication for opposition, period of time in which other companies and inventors can challenge the proposed patent grant. (Not in the US)
  6. Grant of patent if standards for patentability are met.

The specifics of the review process include:
  1. Verifying that claims are for a patentable subject matter.
  2. Unity of invention, since each patent application can only be for one invention (called "restriction" practice in the United States).
  3. Formalities. Is the claim grammatically correct, properly drawn, and unambiguous?
  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 and non-obviousness.

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 lacks utility (usefulness) if it does not have a described specific, substantial, and credible use.

Generally speaking, there are three broad categories of patentable subject matter: processes, machines, and articles of manufacture. Processes include algorithms, business methods, most software, medical techniques, sports techniques and the like. Machines includes devices and apparatuses. Articles of manufacture include mechanical devices, electrical/electronic devices and compositions of matter such as chemicals, medicines, DNA, RNA, etc.

Mathematical truths, however, are not patentable, and software inventions implementing algorithms are not patentable for this reason unless there is some kind of practical application (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.

Presently in 2001, the patenting 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 software as such is 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 and medical treatment techniques 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.


Novelty relates to whether something existed before its "invention" by the applicant or was divulged to the public before the patent application's filing date. For public disclosures of the invention by the inventor, the United States permits a 1 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 divulged 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 and issued patents, etc.) that predate the filing date of the particular patent application.

The comparison of the relevant prior art to the claimed invention can be highly technical in the sense that if the patent claim requires a blade to be between "5 and 10 cm" and a particular reference (one piece of literature found by the examiner) speaks of a blade having a length of "at least 11 cm", then the reference is insufficient to defeat the novelty of the claimed invention.

"Non-obviousness" or "Inventive Step"

Even if an applicant's claim for an invention is technically novel (i.e. not taught by a single prior art reference), a patent can still be denied to the applicant if the applicant's subject matter is "obvious". 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 of 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 applications for United States patents 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 reason 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 consideratons 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. Continuing the example of the claim limitation of a blade that is between "5 and 10 cm", if a second reference were found that said something like "in many instances where long blade sizes are required smaller length blades can be used with equal efficacy", then the examiner would argue that the two references in combination teach or suggest the claimed limitation.

The threshold for the obviousness standard can be particularly frustrating 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, what 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 than that 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). The next day, can someone else file a patent on an "improved" quicksort suitable for use on any set where a partial ordering can be defined (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.

Term of patent

As TRIPS treaty declares the 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 twenty years from the earliest claimed filing date. The rules for patents in force and pending at the transition date (June 8, 1995) are significantly more complicated but grant the patentee whichever term is longer.

Also, in several countries there are multiple types of patents, and the twenty year term frequently only applies to so called 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.

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 England with the Statute of Monopolies in 1624 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. 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. Parliament eventually restricted the crown's power explicitly through the Statute of Monopolies so that the King could only issue letters patents to the inventors or introducers of original inventions for a fixed number of years. Section 6 of the Statute refers to "manner[s] of new manufacture . . . [by] inventors", and this section remains the foundation for patent law in England and Australia. The Statute of Monopolies was latter developed by the courts to produce modern patent law; this innovation was soon adopted by other countries.

On July 31, 1790 inventor Samuel Hopkins became the first person issued patent in the United States. In 1834, the first black man granted a patent, Henry Blair (of Glenross, Maryland), patents a corn planter. In 1836, on August 31, Blair was issued a cotton seed planter patent. In 1863, Alfred Nobel gains Swedish patent for the preparation of nitroglycerin (originally called "blasting oil"). In 1868, Nobel patented form of safe handling dynamite.


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

''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

See also: law, intellectual property, chemical patent, software patent, list of top United States patent recipients.

Patent Discussion

Patent Resources