The concept of "Unity of invention" or "one patent for one invention" found its place in the Indian patent statutes way back in 1911. Specifically, Section 5(1)(b) of the Patents and Designs Act, 1911, empowered a Controller of Patents to refuse an application for patent or required the applicant to delete the distinct inventions if a patent application comprised of more than one inventions. However, the said Act of 1911 had no provision for filing a subsequent/further application out of the disclosure or teachings of the main application for patent.

Consequently, the Patents and Designs (Amendment) Act, 1930, under amended Section 5(1)(f ) prescribed that "when a specification comprises more than one invention, the application shall, if the Controller or the applicant so requires, be restricted to one invention and the other inventions may be made the subject-matter of fresh applications; and any such fresh application shall be proceeded with as a substantive application". Hence, a remedy of filing of a "divisional application" was first introduced in the Indian Patents statute by the said amendment under the 1930 Act.

Coming to the present statue, the Patents Act, 1970, the "Unity of invention" in an application is ensured by Sub-Section (5) of Section 10 of the Act which, prescribes that the claims of a complete specification shall relate to a single invention, or to a group of inventions linked so as to form a single inventive concept.

Further, Section 16 of the Patents Act, 1970, provided the provisions and requisites for filing of a divisional application out-of the first filed application (or parent application):

16. Power of Controller to make orders respecting division of application. –

(1) A person who has made an application for a patent under this Act may, at any time before the grant of the patent, if he so desires, or with a view to remedy the objection raised by the Controller on the ground that the claims of the complete specification relate to more than one invention, file a further application in respect of an invention disclosed in the provisional or complete specification already filed in respect of the first mentioned application.

The pertinent points to note in the said enabling provision are:

  1. A divisional application can be filed at any time before the grant of the patent; and
  2. An applicant may file a divisional application voluntarily ("if he so desires"), or to remedy the Controller's objection on the ground that the claims of the parent application relate to more than one invention;

Sub-Section (2) of Section 16 prescribes that the complete specification of the divisional application(s) shall not include any new subject matter over the original application or disclosure:

16(2). The further application under sub-section (1) shall be accompanied by a complete specification, but such complete specification shall not include any matter not in substance disclosed in the complete specification filed in pursuance of the first mentioned application.

And, Sub-Section (3) of Section 16 ensures that the subject matter claimed in the divisional application shall be distinct from that claimed in the original specification:

16(3). The Controller may require such amendment of the complete specification filed in pursuance of either the original or the further application as may be necessary to ensure that neither of the said complete specifications includes a claim for any matter claimed in the other.

Lastly, by way of Explanation, Section 16 provides that the divisional application shall be deemed to have been filed on the date of filing of the parent application (ante-dating of the divisional application):

Explanation.-For the purposes of this Act, the further application and the complete specification accompanying it shall be deemed to have been filed on the date on which the first mentioned application had been filed, and the further application shall be proceeded with as a substantive application and be examined when the request for examination is filed within the prescribed period.

Upon reading the said statutory provisions, one can safely construe that the principal purpose of divisional application is to protect the applicant's rights (by filing a further application) in case there is more than one invention disclosed or taught in the complete specification. Further, the requisites or criteria of the said enabling provision, i.e., Section 16, seem to be quite simple and direct. However, the same is much intricate than it seems.

On close reading, the Section 16, Sub Section (1) can be dissected to read as:

A person who has made an application for a patent under this Act may, at any time before the grant of the patent,

  1. if he so desires, or
  2. with a view to remedy the objection raised by the Controller on the ground that the claims of the complete specification relate to more than one invention,

file a further application in respect of an invention disclosed in the provisional or complete specification already filed in respect of the first mentioned application.

Accordingly, it can be construed that an applicant may file a divisional application voluntarily, if he desires, and looking at phrase ",or" after (a) above, it appears that the condition of parent application relating to more than one application is applicable only to the remedy in option (b). On the said interpretation/ construction of the Section 16(1), several divisional applications were filed at the Patent Office even with same set of claims as of the parent application, and without claiming an invention distinct from that claimed in the parent application/patent.

More particularly, the applicants started misusing the 'if he so desires' provision of the section under instances such as: where an applicant failed to attend to the objection(s) raised in the examination report within the prescribed period or failed to convince the Controller adequately for grant of a patent, the applicant started filing a divisional application with the same set of claims as in the parent application so as to secure a second chance at patenting the claimed invention.

The above understanding however was overturned and negated by the Intellectual Property Appellate Board (IPAB) in its decisions in appeal instances of: Bayer Animal Health GmbH v Union of India (OA/18/2009/ PT/DEL) and LG Electronics Inc v Controller of Patents & Designs (OA/6/2010/PT/KOL). In both said cases the applicants opted to file a divisional application with claims relating to the same invention, i.e., the parent applications did not relate to plurality of invention. The IPAB held that:

"The basis of divisional application is the existence of a plurality of invention. This is a sine qua non for seeking a division of an application."

Accordingly, the IPAB has mandated the condition of plurality of inventions for filing a divisional application by volition or to remedy an objection by the Controller. Particularly, in LG Electronics case, the IPAB stated that the usage of word 'or' was conjunctive with its aim, i.e., even if the applicant wished to divide the patent application suo moto, it would have to be primarily based on the fact that the application contains a plurality of inventions not linked by single inventive concept.

Therefore, while proceeding with a divisional application in India, an applicant shall keep in mind that the divisional application shall be filed before the grant of patent over the parent application, parent application shall disclose or teach more than one invention in substance, specification of divisional application shall not disclose a subject matter not covered in the parent application, claims of the divisional application shall be duly supported by the parent specification, the claims of the parent and divisional application shall be distinct, i.e., the divisional application shall not claim a subject matter already claimed in parent application/patent.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.