Patents Act, 1970
54. Patents of addition
(1) Subject to the provisions contained in this section, where
an application is made for a patent in respect of any improvement in or
modification of an invention described or disclosed in the complete
specification filed therefor (in this Act referred to as the "main
invention") and the applicant also applies or has applied for a patent for
that invention or is the patentee in respect thereof, the Controller may, if
the applicant so requests, grant the patent for the improvement or modification
as a patent of addition.
(2) Subject to the provisions contained in this section, when an
invention, being an improvement in or modification of another invention, is the
subject of an independent patent and the patentee in respect of that patent is
also the patentee in respect of the patent for the main invention, the
Controller may, if the patentee so requests, by order, revoke the patent for
the improvement or modification and grant to the patentee a patent of addition
in respect thereof, bearing the same date as the date of the patent so revoked.
(3) A patent shall not be granted as a patent of addition unless
the date of filing of the complete specification was the same as or later than
the date of filing of the complete specification in respect of the main
invention.
(4) A patent of addition shall not be sealed before the sealing
of the patent for the main invention, and if the period within which, but for
the provisions of this sub-section, a request for the sealing of a patent of
addition could be made under section 43 expires before the period within which
a request for the sealing of the patent for the main invention may be so made,
the request for the sealing of the patent of addition may be made at any time
within the last mentioned period.