Ways in which a patent may expire?
A patent can expire in the following ways: 1. The patent has lived its full term i.e. the term specified by the patent act of the country. Generally it is 20 years from the date of filing. 2. The patentee hs failed to pay the renewal fee. A patent once granted by the Government has to be maintained by paying annual renewal fee. 3. The validity of the patent has been successfully challenged by an opponent by filing an opposition either with the patent office or with the courts.
