Submarine patent

A submarine patent is a patent whose issuance and publication are intentionally delayed by the applicant for a long time, such as several years. This strategy requires a patent system where, first, patent applications are not published, and, second, patent term is measured from grant date, not from priority or filing date. In the United States, patent applications filed before November 2000 were not published and remained secret until they were granted. Analogous to a submarine, therefore, submarine patents could stay "under water" for long periods until they "emerged" and surprised the relevant market. Persons or companies making use of submarine patents are sometimes referred to as patent pirates.

The phrase is occasionally used more generally for any patent used in patent ambush.

Submarine patent practice was possible previously under the United States patent law, but is no longer practical since the U.S. signed the TRIPS Agreement of the WTO: since 1995, patent terms (20 years in the U.S.) are measured from the original filing or priority date, and not the date of issuance. A few potential submarine patents may result from pre-1995 filings that have yet to be granted and may remain unpublished until issuance. Submarine patents are considered by some, including the US Federal Courts, as a procedural laches (a delay in enforcing one's rights, which may cause the rights to be lost).

In the past, when the life of a U.S. patent was 17 years from the date it was granted, submarine patents could issue decades after the initial filing date. Therefore, an applicant for a U.S. patent could benefit by delaying the issuance, and thus expiration date, of a patent through the simple, but relatively costly, expedient of filing a succession of continuation applications. Some submarine patents emerged as much as 40 years after the date of filing of the corresponding application. During the extended prosecution period the claims of the patent could be modified to more closely match whatever technology or products had become the industry standard.

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Wikipedia