A defensive publication, or defensive disclosure, is an intellectual property

Intellectual property

Intellectual property is a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law...

 strategy used to prevent another party from obtaining a patent

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....

 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 so that it enters the public domain

Public domain

Works are in the public domain if the intellectual property rights have expired, if the intellectual property rights are forfeited, or if they are not covered by intellectual property rights at all...

 and becomes prior art

Prior art

Prior art , in most systems of patent law, constitutes all information 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...

. Therefore, the defensive publication of perhaps otherwise patentable

Patentability

Within the context of a national or multilateral body of law, an invention is patentable if it meets the relevant legal conditions to be granted a patent...

 information may work to defeat the novelty

Novelty (patent)

Novelty is a patentability requirement. An invention is not patentable if the claimed subject matter was disclosed before the date of filing, or before the date of priority if a priority is claimed, of the patent application....

 of a subsequent 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...

.

One reason why companies decide to use defensive publication over patents is cost. In the United States, for example, patents incur at least a filing fee (currently $82-330), plus larger maintenance costs ($490-4,110) at scheduled times. The cost of defensive publication can be zero, like a conference paper.

"The defensive publication route is especially useful for innovations that do not warrant the high costs incurred in patent applications but to which scientists do want to retain access."

See also

• IBM Technical Disclosure Bulletin
  IBM Technical Disclosure Bulletin
  The IBM Technical Disclosure Bulletin was a technical publication produced by IBM between 1958 and 1998. The purpose of the Bulletin was to disclose inventions that IBM did not want their competitors to get patents on. The Bulletin was a form of defensive publication...
  
  
• 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...
  
  
• United States Defensive Publication
  United States Defensive Publication
  A United States Defensive Publication is a published patent application for which the inventor has elected not to get patent coverage. Defensive Publications were made between April 1968 and May 8, 1985...
  
  

Further reading

• Johnson, Justin P., Defensive Publishing by a Leading Firm (October 8, 2004). Available at SSRN: http://ssrn.com/abstract=606781 or DOI: 10.2139/ssrn.606781 (pdf).
• Baker, Scott and Doug Lichtman and Claudio Mezzetti, Disclosure And Investment As Strategies In The Patent Race, University of Chicago Law School. 2000. (pdf)