Prior art
Prior art in most systems of patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

 law, constitutes all information
Information in its most restricted technical sense is a message or collection of messages that consists of an ordered sequence of symbols, or it is the meaning that can be interpreted from such a message or collection of messages. Information can be recorded or transmitted. It can be recorded as...

 that has been made available to the public in any form before a given date that might be relevant to a patent's claims of originality. If an invention
An invention is a novel composition, device, or process. An invention may be derived from a pre-existing model or idea, or it could be independently conceived, in which case it may be a radical breakthrough. In addition, there is cultural invention, which is an innovative set of useful social...

 has been described in prior art, a patent on that invention is not valid.

Information kept secret, for instance, as a trade secret
Trade secret
A trade secret is a formula, practice, process, design, instrument, pattern, or compilation of information which is not generally known or reasonably ascertainable, by which a business can obtain an economic advantage over competitors or customers...

, is not usually prior art, provided that employees and others with access to the information are under a non-disclosure obligation. With such an obligation, the information will typically not be regarded as prior art. Therefore, a patent may be granted on an invention, although someone else already knew of the invention. A person who used an invention in secret may in some jurisdictions be able to claim "prior user rights" and thereby gain the right to continue using the invention. As a special exception, earlier-filed and unpublished patent application
Patent application
A patent application is a request pending at a patent office for the grant of a patent for the invention described and claimed by that application. An application consists of a description of the invention , together with official forms and correspondence relating to the application...

s do qualify as prior art as of their filing date in certain circumstances.

In order to anticipate a claim, prior art is generally expected to provide a description sufficient to inform an average worker in the field (or the person skilled in the art) of some subject matter falling within the scope of the claim. Prior art must be available in some way to the public, and in many countries, the information needs to be recorded in a fixed form somehow. Prior art generally does not include unpublished work or mere conversations (though according to the European Patent Convention
European Patent Convention
The Convention on the Grant of European Patents of 5 October 1973, commonly known as the European Patent Convention , is a multilateral treaty instituting the European Patent Organisation and providing an autonomous legal system according to which European patents are granted...

, oral disclosures also form prior art—see ). It is disputed whether traditional knowledge
Traditional knowledge
Traditional knowledge , indigenous knowledge , traditional environmental knowledge and local knowledge generally refer to the long-standing traditions and practices of certain regional, indigenous, or local communities. Traditional knowledge also encompasses the wisdom, knowledge, and teachings...

 (e.g., of medical properties of a certain plant) constitutes prior art.

Patents disclose to society how an invention is practiced, in return for the right (during a limited term) to exclude others from manufacturing, selling, offering for sale or using the patented invention without the patentee's permission. Patent offices deal with prior art searches in the context of the patent granting procedure. To assess the validity of a patent application, patent offices explore the prior art that was disclosed before the invention occurred (in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

) or before the filing date (in the rest of the world).

First-to-invent versus first-to-file

A first-to-file rule is followed in most countries other than the United States. Under the rule, regardless of who the first inventor was, the person or legal entity who files a patent application first is the one who is granted the patent. In 2011, President Obama signed the Leahy-Smith America Invents Act which changes the US to a first to file system for patent applications filed on or after March 16, 2013.

A first-to-invent rule is followed in the United States for applications filed before March 16, 2013. Invention is generally defined to comprise two steps: conception of the invention and reduction to practice of the invention. When an inventor conceives of an invention and diligently reduces the invention to practice (by filing a patent application, by practicing the invention, and so on), the inventor's date of invention will be the date of conception. Thus, provided an inventor is diligent in reducing an application to practice, he or she will be the first inventor, and the inventor entitled to patent, even if another files a patent application (reduces the invention to practice) before the inventor.

Efforts are currently being made to unify the patent laws of various countries, so that inventors have the same rights regardless of the country where a patent is granted.

Other considerations

Although patents normally go to the first inventor under a first-to-file system, an inventor who keeps the information secret or does not publish it does not establish prior art and loses the right to the patent. Without prior art, a subsequent inventor can get a valid patent on the same invention and then apply it against earlier inventor(s). An earlier inventor can forestall such an act by a subsequent inventor by recognizing the invention and applying for a patent, or by publishing details of how to practice the invention, thus creating prior art.


A "novelty search" is a prior art search that is often conducted by patent attorneys, patent agents
Patent attorney
A patent attorney is an attorney who has the specialized qualifications necessary for representing clients in obtaining patents and acting in all matters and procedures relating to patent law and practice, such as filing an opposition...

 or professional patent searchers before an inventor files a patent application
Patent application
A patent application is a request pending at a patent office for the grant of a patent for the invention described and claimed by that application. An application consists of a description of the invention , together with official forms and correspondence relating to the application...

. A novelty search helps an inventor to determine if the invention is novel before the inventor commits the resources necessary to obtain a patent. The search may include searching in databases of patents, patent applications and other documents such as utility model
Utility model
A utility model is an intellectual property right to protect inventions. This right is available in a number of national statutes, as described below...

s and in the scientific literature
Scientific literature
Scientific literature comprises scientific publications that report original empirical and theoretical work in the natural and social sciences, and within a scientific field is often abbreviated as the literature. Academic publishing is the process of placing the results of one's research into the...

. A search of this type is also conducted by patent examiners during prosecution of the patent application. For instance, examiner's search guidelines applicable to the United States are found in MPEP 904.02.

A "validity search" is a prior art search done after a patent issues. The purpose of a validity (or invalidity) search is to find prior art that the patent examiner overlooked so that a patent can be declared invalid. This might be done by an entity infringing, or potentially infringing, the patent
Patent infringement
Patent infringement is the commission of a prohibited act with respect to a patented invention without permission from the patent holder. Permission may typically be granted in the form of a license. The definition of patent infringement may vary by jurisdiction, but it typically includes using or...

, or it might be done by a patent owner or other entity that has a financial stake in a patent to confirm the validity of a patent.

A clearance search is a search of issued patents to see if a given product or process violates someone else's existing patent. If so, then a validity search may be done to try to find prior art that would invalidate the patent. A clearance search is a search targeting patents being in force and may be limited to a particular country and group of countries, or a specific market.

Duty of disclosure

In the United States, inventors and their patent agents or attorneys are required by law to submit any references they are aware of to the United States Patent and Trademark Office
United States Patent and Trademark Office
The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...

 that may be material to the patentability of the claims in a patent application they have filed. The patent examiner will then determine if the references qualify as "prior art" and may then take them into account when examining the patent application. If the attorney/agent or inventor fails to properly disclose the potentially relevant references they are aware of, then a patent can be found invalid for inequitable conduct
Inequitable conduct
In United States patent law, inequitable conduct is a defense to allegations of patent infringement. Even in the instance that a patent is valid and infringed, the court ruling on infringement may exercise its equitable discretion not to enforce the patent if the patentee has engaged in inequitable...


At least Japan also has a duty of disclosure. Australia has abolished its duty of disclosure with regard to the results of documentary searches by, or on behalf of, foreign patent offices, except where: (a) normal exam was requested before April 22, 2007, and (b) the foreign patent office search issued before April 22, 2007, and (c) acceptance (allowance) was officially advertised before July 22, 2007.

Public participation in patent examination

With the advent of the Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

, a number of initiatives have been undertaken to create a forum where the public at large can participate in prior art searches. These forums have been related to both issued patents and pending patent applications.

Pending patent applications

More recently, different attempts to employ open Internet-based discussions for encouraging public participation commenting on pending U.S. applications have been started. These may take the form of a wiki
A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...


Patent examiners often use the online encyclopedia Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...

 as a reference to get an overall feel for a given subject. Citations of Wikipedia as actual prior art are problematic, however, due to the fluid and open nature of its editing.

See also

  • Defensive publication
    Defensive publication
    A defensive publication, or defensive disclosure, is an intellectual property strategy used to prevent another party from obtaining a patent on a product, apparatus or method for instance. The strategy consists in disclosing an enabling description and/or drawing of the product, apparatus or method...

  • Illegal number
    Illegal number
    An illegal number is a number that represents information which is illegal to possess, utter or propagate. Any information that can be represented in binary format is representable as a number, and therefore if the information itself is illegal in some way, the pure number itself may be...

    , illegal prime
    Illegal prime
    An illegal prime is a prime number that represents information that it is forbidden to possess or distribute. One of the first illegal primes was discovered in 2001. When interpreted in a particular way, it describes a computer program that bypasses the digital rights management scheme used on DVDs...

  • Information disclosure statement
    Information disclosure statement
    An information disclosure statement refers to a submission of relevant background art or information to the United States Patent and Trademark Office by an applicant for a patent during the patent prosecution process...

  • Internet as a source of prior art
    Internet as a source of prior art
    In the context of patent law, using the Internet as a source of prior art when assessing whether an invention is novel and inventive, is problematic since it is often difficult to ascertain precisely when information on websites became available to the public...

  • Micropatent
    Micropatent is a subsidiary of the Thomson Corporation . It is a commercial source for online patent and trademark information...

  • Patent classification
    Patent classification
    A patent classification is a way the examiners of patent offices or other people arrange documents, such as patent applications, disclosing inventions according to the technical features of the inventions...

  • Patent watch
    Patent watch
    In patent law, a patent watch is a process for monitoring newly issued patents on a periodic basis to see if any of these patents might be of interest. Patent watches may for instance be performed on a quarterly basis. It is common practice for corporations in patent-based businesses In patent...

  • Priority right
    Priority right
    In patent, industrial design rights and trademark laws, a priority right or right of priority is a time-limited right, triggered by the first filing of an application for a patent, an industrial design or a trademark respectively...

  • Public participation in patent examination
    Public participation in patent examination
    The involvement of the public in patent examination has been proposed and is currently used in some forms to help identifying relevant prior art and, more generally, to help assessing whether patent applications and inventions meet the requirements of patent law, such as novelty, inventive step or...

  • Search report
    Search report
    In patent law, a search report is a report established by a patent office, which mentions documents which may be taken into consideration in deciding whether the invention to which a patent application relates is patentable...

Notable prior art databases

  • Espacenet—European Patent Office
    European Patent Organisation
    The European Patent Organisation is a public international organisation created in 1977 by its contracting states to grant patents in Europe under the European Patent Convention of 1973...

     public prior art database.
  • Google Patents
    Google Patents
    Google Patents is a search engine from Google that indexes patents and patent applications from the United States Patent and Trademark Office , which are taken from the original USPTO database . All 8 million patents have been put in the database. Optical character recognition has been...

    —search engine from Google
    Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...

     that indexes patents from the United States Patent and Trademark Office
    United States Patent and Trademark Office
    The United States Patent and Trademark Office is an agency in the United States Department of Commerce that issues patents to inventors and businesses for their inventions, and trademark registration for product and intellectual property identification.The USPTO is based in Alexandria, Virginia,...


For other patent search services, see :Category:Patent search services.

Further reading

Official institutions

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.