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In India, every patent application should form a “single invention concept” (and therefore amount to “one invention”). However, where a parent application contains multiple group of inventions and they do not form such a “single invention concept”, a divisional application is taken up. These applications are governed by several provisions, namely Sections 16, 10(5) and 7(1) of the Patents Act 1970.

These provisions provide that, inter alia, a divisional application should not contain any additional subject matter in the complete specification filed in pursuance of the parent application and that the subject matter claimed in the divisional application should be distinct from the parent application.  The application of these provisions has been further clarified by the decisions of the Intellectual Property Appellate Board (IPAB).

Previously, in the case of L.G. Electronics v. Controller of Patents (2011) (OA/6/2010/PT/KOL)( L.G. Electronics”), the IPAB provided that in a divisional application filed to remedy the objection raised by the Controller, the grounds of the divisional application should be due to dividing multiple inventions in the parent application only. The divisional application cannot be used to exercise the revival of subject matter in the parent application that has been abandoned, refused, or withdrawn.

Recently, the IPAB has further clarified the rules viz filing a divisional application in the case of Esco Corporation v. The Controller of Patents & Designs (2020) (OA/66/2020/PT/DEL) (“Esco Corporation”). Esco Corporation reiterated the position in L.G. Electronics that in order for a divisional application to be filed, multiple groups of inventions are mandatory, and that any claim deemed to be unpatentable due to any provisions of the law should not be allowed in the divisional application. However, the IPAB in Esco Corporation also added that the claims of the divisional application should only be based on the claims already made in the parent application. Therefore, it is now clear that additional claim(s) would not be allowed as part of a divisional application.

Moreover, it was also held that the claims of the divisional application should not include any subject matter that has been claimed in the parent application, and instead, should be distinct with no similar set of claims as the parent application. In the event that these rules are not followed, the divisional application will fail for not forming a “single invention concept”.

The IPAB in Esco Corporation Case, relies on, inter alia, Rule 13 of the Patent Cooperation Treaty (PCT) to define a “single inventive concept”. As per Rule 13.2 of the PCT, the requirement of unity of invention is only fulfilled where there is a technical relationship among those inventions involving one or several special technical features, and that the special technical features define a contribution which each of the claim inventions, considered as a whole, makes over the prior art. The IPAB calls this the “One Application One Inventive Concept (OAIC)” theme.

The IPAB in Esco Corporation Case also clarified the law in the filing of cascading divisional applications (i.e. where a divisional application is made based on another divisional application). In particular, it has clarified the reason why it should be allowed, that is: “the applicant should not be left in [a] lurch mainly on the basis of the objection raised by the office which necessitated the applicant to [resort] to file divisional application as the subject in the instant case without any remedial measures available in accordance with law.” Similar positions were also undertaken by the IPAB in the cases of Procter & Gamble Company v. The Controller of Patents & Designs (OA/47/2020/PT/DEL) and National Institute of Immunology v. The Assistant Controller of Patents & Designs (OA/21/2011/PT/DEL).

Further, the IPAB also encourages the minimisation of filing cascading divisional applications. In our view, this can only be achieved if the IPAB identifies all the distinct inventions in the First Examination Report wherever the lack of “unity of invention” exists in a parent application. Thereafter, if there are multiple sets of distinct claims, the Applicant can file all divisional applications at once.

Also, as mentioned earlier, if a “unity of invention” objection is raised, the Applicant should have a chance to do remedial action to overcome the objection raised by the office by filing divisional application to overcome the objection. The Controller reviewing the application should not deny the divisional application entirely, and allow the Applicant to make amendments to the application, in view of the statutory provisions in the Patent Act.


It is reassuring that steps are being taken by IPAB to facilitate a uniform practice for handling divisional applications. With guiding principles such as these, we are able to anticipate a more consistent approach from both the Applicants and Registry for the filing and prosecution of divisional application in the near future.