The stock answer is that a patent is enforceable for 20 years upon filing. However, this is not the complete picture. First off, the patent term doesn’t start until grant of the patent which may be anywhere from a few months for design patent and a couple of years for a utility patent. The patent term is dependent upon the following factors:
1. Was the first filed patent application a non provisional patent application or provisional patent application? Provisional patent applications do not affect the patent term of any patent maturing from the follow-on non-provisional patent application.
2. Were there any delays either by the patent applicant or the patent office. The USPTO will give the patent applicant a patent term extension for any delays by the patent office. The USPTO will subtract from the patent term extension for any delays by the patent application.
3. If a terminal disclaimer was filed, then the patent term is coextensive with the patent term of the parent application. Also, if you separate the patent in which the terminal disclaimer was filed from the base patent, then patent becomes unenforceable.
4. Were all maintenance fees paid and current? If you fail to pay a maintenance fee, then the patent expires.
As an Orange County Patent Attorney, I serve Orange County, Irvine, Los Angeles, San Diego and surrounding cities.