PATENTS OF ADDITION :

Sections 54, 55 and 56 deal with patents of addition. Section 54 provides that 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, namely 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.

Where 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, revoke the patent for the improvement or modification and grant to the patentee a patent of addition in respect thereof, bearing the same date of the patent so revoked. However a patent shall not be granted as a patent of addition unless the date of filing of the application was the same as or later than the date of filing of the application in respect of the main invention. A patent of addition shall not be granted before the grant of the patent for the main invention.

Section 55 deals with term of patents of addition and provides that a patent of addition is granted for a term equal to that of the patent for the main invention or so much thereof as has not expired and remains in force during that term or until the previous ceasser of the patent for the main invention and no longer. No renewal fees is payable in respect of a patent of addition, but if any such patent becomes an independent patent the same fees shall thereafter be payable upon the same dates, as if the patent had been originally granted as an independent patent.

Section 56 which deals with validity of patents of addition provides that the grant of a patent of addition shall not be refused and a patent granted as a patent of addition shall not be revoked or invalidated, on the ground only that the invention claimed in the complete specification does not involve any inventive step having regard to any publication or use of the main invention described in the complete specification relating thereto; or any improvement in or modification of the main invention described in the complete specification of a patent of addition to the patent for the main invention or of an application for such a patent of addition, and the validity of a patent of addition shall not be questioned on the ground that the invention ought to have been the subject of an independent patent. In this context, it is clarified that in determining the novelty of the invention claimed in the complete specification filed in pursuance of an application for a patent of addition regard shall be had also to the complete specification in which the main invention is described.