How Patent Terms are Calculated in the U.S.
The rules for calculating patents terms changed when the US implemented policies set forth by the Agreement on Trade Related Aspects of Intellectual Property Rights (TRIPS). Prior to this implementation, the term of a US extended 17 years from the issue date. However, to be consistent with the TRIPS recommendations, the policy in the US changed in 1995. The current patent term is extends 20 years from the earliest filing date instead of 17 years from the issue date.
Rather than retroactively changing the patent terms for patents that were pending or in force prior to the policy change, the US has adopted a scheme in which the patent term is calculated based on the longer of the two possible patent terms (17 years from the issue date, or 20 years from the earliest filing date). This makes the calculation of patent terms for older patents somewhat complicated. June 8, 1995 was the "magic date" when the patent term calculation changed.
In terms of patent term calculations, US patents generally fall into 4 categories. The figure below shows a relative timeline for the calculation of patent terms, with the colored bars corresponding to each of the four categories. The bars represent the the pendency of applications, from the filing of the application to the issue date.
Category 1
Patents that issued prior to or on June 7, 1978 had a term that was 17 years from the issue date. These patents have all expired.
Example: US Patent No. 4,087,044 was filed on November 26, 1976 and issued on May 2, 1978. Its expiration date was May 2, 1995; 17 years from the issue date.
Category 2
Patents that were filed after June 7, 1978 and issued before June 8, 1995. These applications have a term that is the longer of the two following options:
1) 17 years from the issue date of the application, or
2) 20 years from the earliest filing date.
The term "earliest filing date" means that if the patent application in question is a continuation or divisional application of an earlier US application (the "parent" application), then the filing date of the "parent" is the earliest filing date and is used for calculating the patent term.
In addition, if the application in question is a US nationalization of a PCT application, than the PCT application filing date is used as the earliest filing date.
If the application of interest claims priority to a provisional patent application, the provisional application filing date is not considered to be the earliest filing date.
If the application is a US nationalization of a PCT application that was first filed in another (foreign) country, the PCT filing date is considered to be the earliest filing date, not the date of the prior foreign filing.
Example: US Patent No. 5,011,685 was filed on September 10, 1990 and issued on April 30, 1991. It was a divisional application that claimed priority to a parent application that was filed on April 6, 1998. A patent term extending 20 years from the earliest filing date, April 6, 1998, would expire on April 6, 2007. However, a patent term extending 17 years from the issue date would expire later in the same month; April 30, 2008. Therefore the 17 year term would apply to this patent.
Category 3
This category applies to applications that were filed before June 8, 1995 and were pending on June 8, 1995. Applications in Category 3 are subject to exactly the same conditions as Category 2; their patent term is the longer of the two following options: 1) 17 years from the issue date of the application, or 2) 20 years from the earliest filing date.
Example: US Patent No. 6,051,757 was filed on June 5, 1995 and issued on April 18, 2000. This application was a continuation application that claimed priority to a parent with a filing date of February 11, 1988. In this case, a term of 20 years from the filing date would lead to an expiration date of February 11, 2008. However, a term extending 17 years from the issue date would lead to an expiration date of April 18, 2017. Because the 17 year expiration date is later than the 20 year expiration date, the predicted expiration date would be April 18, 2017.
US Patent No. 6,936,253 was filed on June 7, 1995 and issued on August 30, 2005. It was a continuation application and has a parent that was filed on January 22, 1993. In this case, a term of 20 years from the filing date would lead to an expiration date of January 22, 2013. However, a term extending 17 years from the issue date, August 30, 2005, would lead to an expiration date of August 30, 2022. Because the 17 year expiration date is later than the 20 year expiration date, the predicted expiration date would be August 30, 2022.
US Patent No. 5,850,015 was filed on June 7, 1995 and issued on December 15, 1998. It was not a continuation or a nationalization of a PCT application. A term of 20 years from the filing date would lead to an expiration date of June 7, 2015. A term extending 17 years from the issue date, December 18, 1998, would lead to a predicted expiration date of December 15, 2015. Because the 17 year expiration date is slightly later than the 20 year expiration date, the predicted expiration date would be December 18, 2015.
Category 4
For applications filed on or after June 8, 1995, the patent term is 20 years from the earliest filing date. Eventually, barring future changes in patent term policy, all patents will expire 20 years from their earliest filing date.
Example: US Patent No. 5,689,056 was filed on November 7, 1995 and issued on November 18, 1997. It is a continuation of an abandoned application that was filed on August 2, 1993. The earliest filing date is August 2, 1993, and therefore the predicted expiration date would be 20 years from that date, or August 2, 2013.
There are a number of other factors that affect the term of the patent in the US, including:
• Terminal disclaimers
• Patent term adjustments
• Patents that have lapsed due to failure to pay maintenance fees
Terminal Disclaimers
A terminal disclaimer is filed when the patentee wants to, or is required to disclaim a portion of, or all of a patent term. When a portion of a patent term is "disclaimed", it is said to have been "dedicated to the public". In effect, terminal disclaimers shorten the term of a patent, and lead to a patent term that expires sooner than would normally be predicted.
Terminal disclaimers are commonly filed to overcome an obviousness-type double-patenting rejection. This type of rejection is generally given when an applicant has two closely-related applications or patents. If the invention in the later-filed application is an obvious improvement of the invention in the first application, the Examiner may require that the later-filed patent expire on the same date as the first-filed patent. When this occurs, the patent term of the second application is shortened, or disclaimed.
Patent Term Adjustments
Sometimes the patent term is extended for reasons of national interest. For example, in the European Community, law provides for extension of the patent term for patents disclosing new drugs for human use, to compensate for patent term lost while the patentee is unable to market a product because government approval is still pending. This is intended to provide a greater incentive for investment into research, opposing the counter-incentive of lengthy regulatory approval processes. Similar patent term restoration is provided by Japan, Israel, the U.S. and many other countries.
In some countries restoration of patent term for time spent in regulatory approvals extends to other types of medical devices, veterinary products and the like, but most often agricultural biotechnology patent applications are not considered under this rubric despite lengthy regulatory approval processes for food crops.
In the US, if the issue of a patent is delayed due to interference proceedings (a procedure attempting to resolve disputes over who was first to invent a particular technology), a secrecy order, or in other limited circumstances such as delays in patent office handling, the term of the patent can be extended for the period of delay, up to a total of five years. If it has been so extended, the extended portion of the term of the patent can be reduced for any period of time during which the applicant did not act with due diligence, such as replying in timely fashion to a patent examiner's question or office action. See a USPTO web page describing how patent term adjustments are calculated.
Lapsed Patents Due to Failure to Pay Maintenance Fees
Patents can lapse if required maintenance fees are not paid. Many countries require the payment of annuities annually, or maintenance payments at other intervals. Sometimes assignees knowingly or unintentionally fail to make such payments, so a patent that would otherwise be predicted to have a longer term may not actually be in force.
Source: Patentlens
Rather than retroactively changing the patent terms for patents that were pending or in force prior to the policy change, the US has adopted a scheme in which the patent term is calculated based on the longer of the two possible patent terms (17 years from the issue date, or 20 years from the earliest filing date). This makes the calculation of patent terms for older patents somewhat complicated. June 8, 1995 was the "magic date" when the patent term calculation changed.
In terms of patent term calculations, US patents generally fall into 4 categories. The figure below shows a relative timeline for the calculation of patent terms, with the colored bars corresponding to each of the four categories. The bars represent the the pendency of applications, from the filing of the application to the issue date.
Category 1
Patents that issued prior to or on June 7, 1978 had a term that was 17 years from the issue date. These patents have all expired.
Example: US Patent No. 4,087,044 was filed on November 26, 1976 and issued on May 2, 1978. Its expiration date was May 2, 1995; 17 years from the issue date.
Category 2
Patents that were filed after June 7, 1978 and issued before June 8, 1995. These applications have a term that is the longer of the two following options:
1) 17 years from the issue date of the application, or
2) 20 years from the earliest filing date.
The term "earliest filing date" means that if the patent application in question is a continuation or divisional application of an earlier US application (the "parent" application), then the filing date of the "parent" is the earliest filing date and is used for calculating the patent term.
In addition, if the application in question is a US nationalization of a PCT application, than the PCT application filing date is used as the earliest filing date.
If the application of interest claims priority to a provisional patent application, the provisional application filing date is not considered to be the earliest filing date.
If the application is a US nationalization of a PCT application that was first filed in another (foreign) country, the PCT filing date is considered to be the earliest filing date, not the date of the prior foreign filing.
Example: US Patent No. 5,011,685 was filed on September 10, 1990 and issued on April 30, 1991. It was a divisional application that claimed priority to a parent application that was filed on April 6, 1998. A patent term extending 20 years from the earliest filing date, April 6, 1998, would expire on April 6, 2007. However, a patent term extending 17 years from the issue date would expire later in the same month; April 30, 2008. Therefore the 17 year term would apply to this patent.
Category 3
This category applies to applications that were filed before June 8, 1995 and were pending on June 8, 1995. Applications in Category 3 are subject to exactly the same conditions as Category 2; their patent term is the longer of the two following options: 1) 17 years from the issue date of the application, or 2) 20 years from the earliest filing date.
Example: US Patent No. 6,051,757 was filed on June 5, 1995 and issued on April 18, 2000. This application was a continuation application that claimed priority to a parent with a filing date of February 11, 1988. In this case, a term of 20 years from the filing date would lead to an expiration date of February 11, 2008. However, a term extending 17 years from the issue date would lead to an expiration date of April 18, 2017. Because the 17 year expiration date is later than the 20 year expiration date, the predicted expiration date would be April 18, 2017.
US Patent No. 6,936,253 was filed on June 7, 1995 and issued on August 30, 2005. It was a continuation application and has a parent that was filed on January 22, 1993. In this case, a term of 20 years from the filing date would lead to an expiration date of January 22, 2013. However, a term extending 17 years from the issue date, August 30, 2005, would lead to an expiration date of August 30, 2022. Because the 17 year expiration date is later than the 20 year expiration date, the predicted expiration date would be August 30, 2022.
US Patent No. 5,850,015 was filed on June 7, 1995 and issued on December 15, 1998. It was not a continuation or a nationalization of a PCT application. A term of 20 years from the filing date would lead to an expiration date of June 7, 2015. A term extending 17 years from the issue date, December 18, 1998, would lead to a predicted expiration date of December 15, 2015. Because the 17 year expiration date is slightly later than the 20 year expiration date, the predicted expiration date would be December 18, 2015.
Category 4
For applications filed on or after June 8, 1995, the patent term is 20 years from the earliest filing date. Eventually, barring future changes in patent term policy, all patents will expire 20 years from their earliest filing date.
Example: US Patent No. 5,689,056 was filed on November 7, 1995 and issued on November 18, 1997. It is a continuation of an abandoned application that was filed on August 2, 1993. The earliest filing date is August 2, 1993, and therefore the predicted expiration date would be 20 years from that date, or August 2, 2013.
There are a number of other factors that affect the term of the patent in the US, including:
• Terminal disclaimers
• Patent term adjustments
• Patents that have lapsed due to failure to pay maintenance fees
Terminal Disclaimers
A terminal disclaimer is filed when the patentee wants to, or is required to disclaim a portion of, or all of a patent term. When a portion of a patent term is "disclaimed", it is said to have been "dedicated to the public". In effect, terminal disclaimers shorten the term of a patent, and lead to a patent term that expires sooner than would normally be predicted.
Terminal disclaimers are commonly filed to overcome an obviousness-type double-patenting rejection. This type of rejection is generally given when an applicant has two closely-related applications or patents. If the invention in the later-filed application is an obvious improvement of the invention in the first application, the Examiner may require that the later-filed patent expire on the same date as the first-filed patent. When this occurs, the patent term of the second application is shortened, or disclaimed.
Patent Term Adjustments
Sometimes the patent term is extended for reasons of national interest. For example, in the European Community, law provides for extension of the patent term for patents disclosing new drugs for human use, to compensate for patent term lost while the patentee is unable to market a product because government approval is still pending. This is intended to provide a greater incentive for investment into research, opposing the counter-incentive of lengthy regulatory approval processes. Similar patent term restoration is provided by Japan, Israel, the U.S. and many other countries.
In some countries restoration of patent term for time spent in regulatory approvals extends to other types of medical devices, veterinary products and the like, but most often agricultural biotechnology patent applications are not considered under this rubric despite lengthy regulatory approval processes for food crops.
In the US, if the issue of a patent is delayed due to interference proceedings (a procedure attempting to resolve disputes over who was first to invent a particular technology), a secrecy order, or in other limited circumstances such as delays in patent office handling, the term of the patent can be extended for the period of delay, up to a total of five years. If it has been so extended, the extended portion of the term of the patent can be reduced for any period of time during which the applicant did not act with due diligence, such as replying in timely fashion to a patent examiner's question or office action. See a USPTO web page describing how patent term adjustments are calculated.
Lapsed Patents Due to Failure to Pay Maintenance Fees
Patents can lapse if required maintenance fees are not paid. Many countries require the payment of annuities annually, or maintenance payments at other intervals. Sometimes assignees knowingly or unintentionally fail to make such payments, so a patent that would otherwise be predicted to have a longer term may not actually be in force.
Source: Patentlens
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