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How to Determine if a Patent has Expired

Digital Online Patent Branding Office Working ConceptThere is not one way to determine if a patent has expired. It takes some research, and if anyone tells you “it looks like it may have expired,” run. They don’t know what they’re talking about. Here are some ways to help you determine if it’s “still alive.”

  1. Look at the front page – If the patent application filing date is after June 8, 1995, the nominal expiration date is 20 years from the earliest non-provisional priority claim upon which the patent is based. On the other hand, if the patent application filing date was on or before June 8, 1995, the nominal expiration date is the longer of 17 years from the date of issue or 20 years from the earliest non-provisional priority claim. Usually, but not always, the priority claim is listed on the front page of the patent. To be sure, a patent lawyer needs to review the complete file history of the patent.
  1. See if the patent end date was extended – First of all, an extension should be noted on the front page, but if you want to know for sure, check the file history. The PTO has been known to take an unbelievable amount of time to complete a patent application, sometimes up to 10 years. Because of this, Congress has stepped in to extend the expiration of the patent to include that 10-year delay, which is only fair.
  1. Determine if the term was shortened – Yes, this may seem crazy, but this too can happen. Sometimes, but not always, this is notated with an asterisk after the patent issue date. Other times, there may not be an asterisk, but maybe a statement on the front page or the first page of description. Or, sometimes there is no indication, but there is a terminal disclaimer in the file history. A patent expiration date can be shortened due to a terminal disclaimer.
  1. Was the patent changed due to a reissue or reexamination – A reissue is typically for a mistake made by the applicant not accurately claiming their invention. A reexamination basically corrects over-broad patent claims that should not have issued in the first place because there is prior art that makes them anticipated or obvious.
  1. Have the maintenance fees been paid? – Check to see if the maintenance fees been paid. They have to be paid to the Patent Office at 3.5 years, 7.5 years and 11.5 years from the date of issue.
  1. Did the patent go through litigation? – There may be a chance that certain claims of the patent may be considered invalid in court. To look further into this, you can check electronic databases such as Lexis or Westlaw.

Unfortunately, there is not one quick way to check the expiration of a patent, so it’s best to do your due diligence as you move forward.