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Definition and Origin

A patent is a set of exclusive rights granted by the government to an inventor for a limited amount of time. The term's origin falls out from the term to patent which means to lay open (to public inspection) and the term letters patent, which originally denoted royal decrees granting monopoly privilege to certain businesses.

Rights Granted and Rights Not Granted

A modern patent is a right to exclude others from building, using or selling the invention. Generally, patents are enforced only through private actions, e.g. civil lawsuits, licensing agreements, etc. Governments typically reserve the right to suspend a patent at will.

The exclusive right is limited to the claimed invention, more specifically to the patent claims that appear at the back of most printed patent publications. The 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 of the listed items is 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, 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 and modifies it to make an improved mouse trap and obtains a patent on the improvement, she cannot build her improved mouse trap without permission (or risking being sued) from the patent owner on the original mouse trap. However, if the original patent owner tried to copy the inventor's improvement, she could sue them to exclude them from using her patented invention without permission.

Continuing the example though, if the inventor's improved mouse trap patent requires a guillotining member, but the original manufacturer copies other aspects of the improvement. The inventor may 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 patent claims 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 point there are a number of significant international treaties governing patent law and the United States, European Union, and Japan, are parties to the significant ones. This has lead to significant harmonization of patent law worldwide particularly in the last ten to fifteen years. Procedurally, the United States system is perhaps one of the more unusual although recent changes in 1999 have brought the Untied States' system further into line with other major patent systems.

Patent grants are national in nature. This means that for an inventor to protect her invention in multiple countries they must separately file patent applications in each country, or region, where they wish to receive protection. Within Europe, it is possible to apply for a patent with the European Patent Office; but these are not true regional patents, see Community Patent for discussion.

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 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 origin is the Constitution in Article One. In other countries, the origin may be a statute or other law or rule.

Examination Process and Procedure

Typically, patents are examined before it is issued or granted. 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 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 (non-United States) examining procedure is:

  1. filing by inventor or applicant
  2. formalizing of application (signatures by inventors or applicant)
  3. initial publication (18 months from earliest claimed filing date)
  4. review by examiner (including back and forth negotiation with applicant to narrow/modify the scope of the claims)
  5. publication for opposition (period of time in which other companies and inventors can challenge the proposed patent grant)
  6. grant (if standards for patentability met)

The specifics of the review process include:

  1. verifying that claims are for a legal subject matter for a patent
  2. unity of invention (each patent application can only be for one thing; similar to "restriction" practice in the United States)
  3. formalities (is the claim properly drawn and unambiguous)
  4. novelty (newness)
  5. non-obviousness

Different patent systems use different terms for these standards. The most important are: patentable submit 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". This generally breaks into two broad categories: processes and compositions of materials. Processes include algorithms, business methods, most software, medical techniques, sports techniques and the like. Compositions of material include chemicals, medicines, DNA, RNA, etc.

Presently in 2001, the patenting of software (and business methods) is quite controversial. The public state of affairs is that the United States publicly allows software and business method patents. You can't patent software 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 asks the question whether or not something existed before. This is the identical thing based on all of the claimed elements. This is accomplished by a search of literature (technical journals, published and issued patents, etc.) that predate the filing date of the particular patent application.

This comparison is highly mechanical in the sense that if the patent claim requires a blade to be between "5-10 cm" and a particular reference (one piece of literature found by the examiner) speaks of using "at least 11 cm", then for the purposes of the novelty standard the reference is insufficient to show the invention is not new.


Obviousness asks the question whether or not given what was already known is the invention sufficiently different that someone of "ordinary skill in the art", e.g. someone who does the type of things relating to the technical field of the invention, would have realized what to do.

By definition this standard and its application will be controversial. Set too high a requirement and nothing is patentable, similarly set too low a requirement and trivial inventions receive patents (a famous software patent, for example, is the "One Click Patent" for buying products in online stores with one mouseclick).

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. Continuing the example of the claim limitation of a blade that is "5-10 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 the claimed limitation.

The threshold for the obviousness standard can be particularly frustrating in genus-species situations. For example, if inventor finds two species of a particular genus, e.g. two particular chemical compositions out of 10,000 in the broader class, 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? A software example, on day one, an inventor unveils quicksort to the world but only discloses it using integers (species). On day two, can someone else file a patent on an "improved" quicksort suitable for use on any set where a partial ordering can be defined (genus)?

Term of Patent

Virtually every country in the world gives a term of twenty years from earliest claimed filing date to define the term of a patent. In the United States, the rules are significantly more complicated. Also, in several countries there are multiple types of patents, in that case, the twenty year term frequently only applies to so called utility patents and not design, petit, or less heavily examined patents.


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

Patents originated in England with the Statute of Monopolies under King James I. Prior to this time, the King could issue letters patent providing any person with a monopoly to produce particular goods or provide particular services. This power was widely abused; thus Parliament restricted it through the Statute of Monopolies so that the King could only issue them to the inventors of original inventions for a fixed number of years. The Statute of Monopolies was latter developed by the courts to produce modern patent law; this innovation was soon copied by other countries.

See Also

See also law, intellectual property, United States Patent