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Patent of Addition

Issued: November 01 2011

A patent is granted to a patentable subject matter if it satisfies the three prerequisites of novelty, utility and inventive step. An invention that comprises of a radical innovation would in all probability satisfy all three prerequisites for patentability. However, the process of invention is not always an all or nothing proposition, for there may be incremental innovations which build upon existing knowledge and resources and involve modest technological changes, thereby enhancing the competence of existing products or processes. The problem with filing patents for such incremental innovations is that they would most likely be rejected because of their lack of inventive step.

In this regard, patents of addition are useful for protecting novel, industrially-applicable but non-inventive improvements or modifications to an already-filed or granted patent application. The provision of patent of addition in India, New Zealand and Australia is akin to the continuation-inpart applications under the American patent system.

In India, the provisions related to patent of addition are provided under Sections 54, 55 and 56 of the Patents Act, 1970. Accordingly, if an applicant feels that he has come across an invention which is an improvement in or modification of an invention for which he has already applied for or has obtained a patent, another application can be made for a patent in respect of such improvement or modification and such an application may be granted by the Controller as a patent of addition.

An application for a patent of addition should have the same filing date or a later filing date than the date of filing of the complete specification in respect of the main invention – it cannot be filed before the filing date of the application of the main invention. Additionally, a patent of addition will not be granted until the patent for the main invention has been granted.

A patent of addition has the same priority date as the patent of the main invention and, as such, expires along with the main patent. An economic benefit from patents of addition is that no separate renewal fees are payable during the term of the main patent. What might be considered a drawback is that the term expires along with the main patent.

Section 54 of the Act also makes it possible to convert an independent patent to a patent of addition at a later date if the subject matter was an improvement in or modification to a main invention by the same applicant or patentee. Subsequently, no renewal fee would be payable as long as the main patent remains in force. On the other hand, if the patent for the main invention is revoked, Section 55 provides that the patent of addition can be made an independent patent for the remainder of the term of the revoked patent on the request made by the patentee. The same renewal fee shall now be payable upon the same dates as if the patent had been originally granted as an independent patent.

When filing an application for patent of addition, the complete specification should include specific reference to the patent number of main patent or the application number of main patent, and a definite statement that the invention comprises an improvement in, or modification of the invention claimed in the specification of the main patent, granted or applied for.

According to the Draft Manual of Patent Practice and Procedure published by the Indian Patent Officewhether a proposed patent of addition is an improvement or a modification of the main patent is established by the Patent Office by drawing a proper comparison between the novel contributions which each specification has made to the art.

A patent of addition must specify the criteria of novelty in view of the main invention; otherwise, the examiner could cite the main invention as a reason for rejection of the patent of addition for lack of novelty. However, a patent of addition cannot be rejected by an examiner for lack of an inventive step in view of the main invention. Additionally, the validity of a patent of addition cannot be questioned on the ground that the invention ought to have been the subject of an independent patent.

In many ways, the provision of patent of addition under the Indian patent system is more beneficial to the applicant than the continuation-inpart (CIP) under the US patent system. For example, a CIP can only be filed while the parent application is pending, i.e. before it issues as a patent or is abandoned, while a patent of addition can be filed at any time during the term of the main patent. Additionally, a separate annuity is payable for a CIP application, so the parent application is usually abandoned.

When a CIP application is filed, only the subject matter which is common to the parent application is given the benefit of the priority date or filing date of the parent application, as applicable, while any new matter added in the CIP application receives the priority based on actual filing date of the CIP. Likewise, in India each claim of the patent has a priority based on the date on which the subject matter of the claim was first disclosed. Thus the claims fairly based on the additional subject matter disclosed in the patent of addition application will have a priority date based on date of filing of such application.

The provision of patent of addition is a highly beneficial yet underutilized provision under the Indian patent system, and is an option worth considering for protecting incremental innovations as well as strengthening the main patent by incorporating features, which were not in possession of the inventor while filing the patent for the main invention.

Lall Lahiri & Salhotra
LLS House, Plot No. B-28,
Sector - 32, Institutional Area,
Gurgaon - 122001, National Capital
Region, India
T: +91 124 2382202, 2382203
F: +91 124 4036823, 2384898

About the Author

Kshitiz Saxena is a registered patent agent and an advocate working as a managing associate in the patents department of Lall Lahiri & Salhotra. As a patent attorney, his work includes advising clients on various patents and designs related issues including conducting FTO searches, prior art searches, IP due diligence and handling of the work covering the entire gambit of the life cycle of the patents and designs applications. His overall experience includes handling the patent portfolio of various companies coming from the different fields of the technology. He has also assisted in the IP related litigation and is well-versed with the filing and prosecution of design applications.


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