The date at which a patent will expire is generally 20 years from the date of filing. However, there are some nuances to the situation which can complicate matters, and patent expiration dates also vary from nation to nation, and may depend on when the patent was filed and issued. When preparing to file a patent, it is a good idea to make sure that one is familiar with the laws which surround patent expiration, to confirm that the application will be valid and to see how long it will be valid for.
Many patent agencies set up a patient expiration that kicks in 20 years after filing. In the United States, if a patent was filed after 8 June 1995, the 20 year period holds true. However, if someone filed for and received a patent before 8 June 1995, the expiration date may be 17 years from the date of issue, or 20 years from the date of filing, depending on which date is further in the future and when the patent was received.
When filing a patent, people are expected to research to confirm that the patent is original and that it is not infringing on an older patent. Once a patent expires, infringement is no longer an issue, because the patent holder does not hold the rights to the patent any more. When a patent is examined by a patent examiner, she or he will also research to confirm that the patent meets the standards set by the government for the issuance of patents.
In the United States, people who take out a utility patent must pay maintenance fees on the patent. If these fees are not paid, the patent will expire even if the 20 year period has not yet elapsed. The procedures for paying maintenance fees are fairly simple, and people have several options which they can use to pay fees, making it easy to keep up and ensure that a patent will not lapse.
In some cases, the expiration dates of patents have been extended by special arrangement. This is most commonly seen with pharmaceutical patents, under the argument that research and development are so costly that the company needs more time under an exclusive patent, or under the argument that a use for a medication is new, allowing the patent to be extended under a new patent application. This practice has been criticized by some advocates who are concerned about the high cost of patented medications.
