Q: is it useful to purchase a abandoned or expired patent?
A:
A patent that expired last week might have some value as you can sue folks for infringing the patent for up to six years earlier than the date of the law suit.
So even a patent that has been expired for a year or two may have some value if there was extensive use in the final years that the patent was alive. But each day the patent is expired, the value will go down if there was infringing activity for many years.
See https://www.law.cornell.edu/uscode/text/35/286
I have not seen a case where the patent being asserted was abandoned rather than expired as people do not normally abandon a patent intentionally if there is reason to keep it alive. (And there are mechanisms to revive a patent that is abandoned unintentionally). So you may have to have a patent litigator look deeper to see if there is any reason that an abandoned patent cannot be used to sue for damages that happened before the patent went abandoned and within six years of filing the law suit.
If you found this answer helpful, you may want to look at my answers to other questions about patent law are available at the bottom of my profile page at
https://lawyers.justia.com/lawyer/kevin-e-flynn-880338
Kevin E Flynn
Marcos Garciaacosta agrees with this answer
A: With the exception of the case listed in the other answer, an expired patent is in the public domain, so you do not need to have any permission to use it.
Justia Ask a Lawyer is a forum for consumers to get answers to basic legal questions. Any information sent through Justia Ask a Lawyer is not secure and is done so on a non-confidential basis only.
The use of this website to ask questions or receive answers does not create an attorney–client relationship between you and Justia, or between you and any attorney who receives your information or responds to your questions, nor is it intended to create such a relationship. Additionally, no responses on this forum constitute legal advice, which must be tailored to the specific circumstances of each case. You should not act upon information provided in Justia Ask a Lawyer without seeking professional counsel from an attorney admitted or authorized to practice in your jurisdiction. Justia assumes no responsibility to any person who relies on information contained on or received through this site and disclaims all liability in respect to such information.
Justia cannot guarantee that the information on this website (including any legal information provided by an attorney through this service) is accurate, complete, or up-to-date. While we intend to make every attempt to keep the information on this site current, the owners of and contributors to this site make no claims, promises or guarantees about the accuracy, completeness or adequacy of the information contained in or linked to from this site.
