Legal Definitions - intervening rights

Definition: Intervening rights are a defense against patent infringement. It allows a person who practiced a patent's broadened claims to continue practicing, even if the patent is later reissued with broader claims due to errors in the original patent.

For example, if a company has been using a certain technology for years and then a patent is issued for that technology, the company may be able to continue using the technology without infringing on the patent if the patent is later reissued with broader claims.

Another example would be if a patent was originally issued with narrow claims, but then the patent is reissued with broader claims due to errors in the original patent. In this case, anyone who was already using the technology covered by the original narrow claims would be allowed to continue using it without infringing on the reissued patent.