The law on dividing patent applications continually evolves. Applicants therefore face dilemmas whether and when to file dividing patent applications.
Dividing or divisional patent applications are subject to sections 16, 10(5) and 7(1) of the Patents Act, 1970. A divisional patent application is allowed only when multiple inventions are claimed in the parent application, and the claims of the parent application and the divisional application are distinct. A divisional application may only be filed before the grant or refusal of its parent application, that is while the parent application is still being considered.
In the recent case of Boehringer Ingelheim International Gmbh v Controller of Patents, the Delhi High Court held that whether the claims of the complete specification relate to more than one invention under section 16, that is a plurality of inventions, depends on the claims in the parent application. If the invention is not covered by the parent application, the divisional application cannot be made solely on its own content. There cannot be duplication of the claims in the parent and divisional applications. This is a narrow interpretation of the provisions governing divisional applications, but there has been no appeal.
When a divisional patent application is made after a previously filed divisional patent application, that is a serial filing of divisional applications, the now defunct Intellectual Property Appellate Board (IPAB) settled that such an application is valid where there is an objection of lack of unity or new subject matter in an earlier divisional application. The IPAB decided that a later divisional application arising from an earlier application is allowed when the claims of the second application are rooted in those of the first. The division of a divisional application is subject to other conditions, such as the requirement for multiple inventions and the first divisional application awaiting a decision.
The best time to file a divisional application is when the parent application claims are subject to a restriction or when there is an objection of lack of unity of invention. If there is no objection that the parent claims lack such unity, a divisional application may still be filed. The divided claims must be removed from the parent application. If the Indian Patent Office (IPO) objects, the applicant must also prove that the divided claims relate to an invention distinct from the claims in the parent application, this being essential for qualification as a divisional application. Claims are for a distinct invention if they solve a different problem from that in the parent application and show a technical effect and an advancement over prior art.
A divisional application should be made when the claims of the parent application relate to more than one invention. The claims for division should fulfil basic conditions, such as not being similar to or a broader version of the claims in the parent application and should relate to an invention distinct from that in the parent application. As there is no advance notice of the decision in a patent application and a divisional application can be filed only while a decision is awaited on the parent application, a divisional application should be filed at the earliest opportunity.
An applicant wishing to file a divisional patent application where the claims for a divisional application have not been claimed in the parent application, may add the desired divisional claims to the pending parent application claims. As already mentioned, the claims should not be similar or broader versions of the claims of the parent application and be for an invention distinct from that in the parent application. If the IPO objects to the added claims because of a lack of unity, the applicant has valid grounds to make a divisional application. It also ensures that the IPO cannot question the validlity of a later divisional application. In that case, unlikely though it may be, if the IPO raises no objection to newly added claims, the applicant gets protection for all the stated claims in the present application only. However, if the IPO objects to the addition of new claims, as is usual, the applicant may withdraw the added claims, forfeit the additional fee paid and continue with the claims in the parent application.