In India, a divisional patent application can be filed if there exists “plurality of inventions’ or in other words, when the parent application lacks ‘unity of invention’. The statutory provision governing the filing of divisional applications, i.e., Section 16[1] of the Indian Patent Act, 1970 (hereinafter referred to as Section 16) has been the subject of scrutiny and debate due to its inconsistent interpretations and application by the Controllers of the Indian Patent Office (IPO) and the applicants.

Although Section 16 clearly states that an applicant has the right to file a divisional application “if he so desires” or “with a view to remedy the objection raised by the Controller”, there existed ambiguity regarding the pre-requisite for filing a divisional application, particularly when filed suo motu. There were several issues if one were to file a divisional application voluntarily, the most critical being the requirement of plurality. Another confusion pertained to whether the plurality must be evident in the claims or it can be disclosed in the specification, although not claimed. When a divisional application was filed suo motu, it faced rigorous examination by the IPO to determine if the claims in the divisional application were derived from the parent application’s claims, justifying the presence of multiple inventions. Historically speaking, the Controllers at the IPO were reluctant to accept divisional applications based on the subject matter that was not included in the original claims of the parent application but rather disclosed in the specification, citing ambiguity in the statute. This led to numerous rejection orders being issued by the IPO. Consequently, for a long time, the prevailing practice was to file a divisional application only when an objection regarding the unity of invention was raised by the IPO. However, due to the disputed interpretation of the statute and ensuing controversies, several issues regarding the allowability of a divisional application emerged that required deliberation.

The key questions that required consideration were:

• Is ‘plurality of inventions’ sine qua non for filing a divisional application?
• Can an applicant file a divisional application suo motu, or it should only be filed in response to a formal objection from the IPO concerning unity of invention?
• Is it permissible for a divisional application to include claims that incorporate subject matter disclosed in the specification (whether provisional or complete) but not reflected in the originally filed claims?
• Can an applicant file a divisional application based on the subject matter of a previously filed divisional application?

The present article answers these questions based on the settled judicial precedents providing an insight into the evolving jurisprudence concerning the subject of filing of divisional applications. It also provides a brief overview of the currently accepted practices as well as the reforms introduced by the IPO to align Indian patent practices more closely with those of other jurisdictions, marking a significant step towards harmonization.

Plurality of inventions: an essential condition

It is a settled legal principle today that ‘plurality of inventions’ is a sine qua non for filing a divisional application. However, it was a while before the clarity in this regard was achieved and this became established as a law. Said condition was first affirmed by the Intellectual Property Appellate Board (IPAB) in the case of LG Electronics Inc. vs. The Controller of Patents & Designs[2], while deliberating upon the maintainability of divisional applications. In said case, the subject application under consideration was a divisional application filed out of an abandoned parent application, wherein the parent application did not contain plurality of distinct applications. Accordingly, the divisional application was rejected for being infructuous and an appeal was filed against the rejection order. Even though the appeal was dismissed, the judgement provided indispensable clarity with respect to the pre-requisite for filing a divisional application, while also providing critical insights with respect to the interpretation of Section 16. The appellant, while interpreting the language of said section, contended that the use of the phrase “if he so desires” and “or” in said section provides the applicant with an unconditional freedom to file a divisional application even when there is no plurality of distinct inventions. However, the respondent alleged that if appellant’s interpretation is considered, it would mean that an applicant will not have any regulated time limit to put his application in order as opposed to the provisions of Section 21(1)[3] of the Act. It was further contended that when Section 16 is read in conjunction with Sections 7(1)[4] and 10(5)[5], it implies that even if an application is filed suo motu, the power with respect to the allowability of a divisional application vests with the Controller and that the Controller is under the obligation to analyse if the parent application truly contains plurality of inventive concepts.

The IPAB held that the primary criterion for eligibility of a patent application to be filed as a divisional application is disclosure of a plurality of inventions in the parent application. To support this, reliance was also placed on the text from Patent Law by P. Narayanan [4th edition 2006] which states that, “where an application relates to more than one invention, the defect may be remedied by filing a further application. This may be done either at the applicant’s own request at any time before the grant of patent (earlier, it was before the acceptance of the complete specification) or with a view to remove the objection raised by the Controller on the ground that the claims of the complete specification relate to more than one invention.” It was opined that the intended purpose of the statutory provision relating to divisional application is to cure any defect relating to multiplicity of inventions and protect said multiple applications. Therefore, existence of plurality of inventions is a must and the phrase “if he so desires” as used in Section 16 is not unconditional. This has been since then reiterated in various IPAB orders and Court judgements such as in Bayer Animal Health Gmbh vs Union of India and Ors[6], Syngenta Participations AG, Switzerland Vs. Union of India and Others[7], The Procter & Gamble Company v. The Controller of Patents & Designs[8], Esco Corporation vs The Controller of Patents and Designs[9], and Syngenta Limited vs. Controller of Patents and Designs (2023)[10].

It is also pertinent to note here that a divisional application should not include a claim for any matter claimed in the parent application.

Filing of a divisional application: suo motu or in response to a formal objection

Another critical issue that was simultaneously addressed and settled during the proceedings of LG Electronics Inc. vs. The Controller of Patents & Designs[11] was with regards to whether a divisional application can be filed suo motu or it must be filed only in response to an objection raised by the IPO. It was confirmed that a divisional application can be filed in either of said conditions; the only sine qua non being existence of a plurality of inventions in the parent application. However, it was also underscored that while the applicant does have the right to file a divisional application, but the power to ascertain its allowability vests with the Controller. The issue was again discussed in the Syngenta case[12], wherein it was observed that the language of Section 16 provides no distinction or dichotomy in the standard with respect to divisional applications filed suo motu and those filed after an objection raised by the Controller.

Permissible claim scope of a divisional application

One of the most controversial issues surrounding the divisional patent practice in India has been regarding the permissible claim scope. The question as to whether divisional applications could be filed based on the subject matter disclosed in the specification, but not claimed in the original claims, has always been a matter of dispute, with various parties having conflicting opinions. Initial IPAB rulings in this regard, as given in UCB Pharma S.A. v. Controller of Patents & Designs[13]and ESCO Corporation[14] held that addition of new claims derived from the description, which were not part of the originally filed claims of the parent application, could not form part of a divisional application. In other words, a divisional application was considered allowable only if it was based on the subject matter claimed explicitly in the parent application. This interpretation of the statute was reaffirmed by the ruling in Boehringer Ingelheim International GMBH v. The Controller of Patents & Anr[15], wherein the Delhi High Court opined that the "unity of invention"/"plurality of inventions," and whether they constituted a "single inventive concept" must be gleaned from the reading of the claims. The Court held that divisional applications could only be filed when the parent application’s claims disclose a "plurality of inventions," and not based solely on the disclosure made in the specification. In other words, the “plurality of inventions” should clearly exist in the claims of the original patent application. The Court also stated that if applicants are permitted to file divisional applications on the basis of disclosure in the complete specification, without such inventions being claimed in the parent application, it would defeat the fundamental rule of patent law i.e., ‘what is not claim is disclaimed’. This was thus, the settled legal position, as was also held by the Court in Nippon A&L Inc. v. The Controller of Patents[16], decided on July 05, 2022.

These judicial rulings created a certain degree of legal uncertainty, reinforcing the notion that divisional applications must be based on the inventions claimed in the parent application. As a result, applicants faced rejections when attempting to file divisional applications based on the subject matter disclosed in the specification, but not claimed in the parent application.

Said issue was finally addressed and resolved by the Division Bench (DB) of the IP Division of the Delhi High Court in Syngenta Limited v. Controller of Patents and Designs[17]. In this case, the applicant's divisional application (7059/DELNP/2011) was initially rejected by the Controller, who argued that the claimed subject matter did not exhibit a plurality of inventions. An appeal was filed before the Delhi High Court[18]. The primary issues before the Court concerned the requirement of ‘plurality of inventions’ when a divisional application was filed suo motu, and whether the plurality of inventions have to be reflected in the claims in the parent application or is it sufficient if the plurality of inventions is reflected in the disclosures in the complete specifications accompanying the claims in the parent application. The Single Judge of the Court disagreed with the view expressed in Boehringer Ingelheim[19] with regards to plurality of inventions to be reflected in claims, the matter was referred to the Division Bench (DB) of the Delhi High Court for consideration.

On perusal of the facts and circumstances of the case, and after due consideration of the statute, the DB opined that irrespective of whether a divisional application is filed suo motu or to remedy an objection raised by the Controller, plurality of inventions is a must. Further, the DB overturned the earlier decision in Boehringer Ingelheim[20] and held that:

The principle of "what is not claimed is disclaimed" does not apply in the context of divisional applications under Section 16. The Court reasoned that a clear reading of said section indicates that a divisional application can be filed based on the disclosures in the provisional or complete specification. It pointed out that provisional filings often lacked claims, and under the view espoused in Boehringer Ingelheim[21], no divisional application would be maintainable when a provisional specification was involved. The Court thus, opined that a divisional application may be filed for inventions disclosed in the parent application’s specification, even if these inventions are not explicitly claimed.

Thus, the Court’s ruling allowed for a more expansive interpretation of Section 16, thereby marked a significant advancement in the legal framework surrounding divisional applications in India. Said decision was also upheld in the case of Gensquare LLC Vs. The Assistant Controller of Patents and Design, Patent Office, Chennai.[22]

Filing of a divisional application from another divisional application

Another issue that often came to the fore was if a divisional application could be filed from another divisional application. This has also been deliberated upon in various cases such as National Institute of Immunology v The Assistant Controller of Patents & Designs[23], wherein it was held that: “A divisional application filed out of another divisional application is valid, provided the progeny application was filed before the grant of its immediate predecessor application”. Allowability of a divisional from a divisional was also reiterated in Esco Corporation[24] and Exxonmobil Chemical Patents Inc. vs The Controller of Patents[25].

As evident, even though the statute provides for the criterion with regards to allowability of divisional applications and time and again said issues have been deliberated upon in Courts, confusion still persisted. However, recent reforms introduced by the IPO laid down all the controversies to rest providing the much-needed clarity.

Patent (Amendment) Rules, 2024

On March 15, 2024, the Patents (Amendment) Rules, 2024 introduced Rule 13(2A)[26], ushering in a liberalized approach to divisional applications. In accordance with said rule, multiple divisional applications can now be filed from either a provisional or a complete specification or even another divisional application.

When to file a divisional application?

A divisional application is required to be filed before the grant of the parent application. However, it is not possible for an applicant to determine the time of grant of an application which may lead to a probability of a divisional being filed on the same day of the grant of the parent application. This interesting issue was dealt with in a recent matter of BASF SE v. The Deputy Controller of Patents and Designs[27], wherein the Controller had rejected the divisional application on the grounds that it was filed after the grant of the patent for the original patent application filed by the Appellant. Upon due consideration of the facts of the case, the Court held that the impugned order was passed with a total non-application of mind, disregarding the admitted fact that the divisional application was filed on the same day the patent was granted. It was opined that it was impossible for the appellant to know the exact timing of the patent grant. Consequently, the Court quashed the impugned order and remanded the matter for fresh consideration of the divisional application filed by the appellant under Section 16 of the Patents Act, 1970, on merits and in accordance with the law.

Current Practices and Reforms

In view of the various judicial precedents and the amendments introduced by the IPO, the following are the established practices with regards to filing of divisional applications in India:

• The requirement for “plurality of inventions” remains fundamental and must be present in either the provisional or complete specification for the filing of a divisional application.
• A divisional application can be filed suo motu by the applicant and does not necessarily have to be filed in response to an objection raised by the Controller regarding unity of invention.
• Multiple divisional applications can be filed based on the subject matter disclosed in either a provisional or complete specification, and not necessarily being claimed.
• Multiple divisional applications can be filed from a previously filed divisional application.
• The concept of “what is not claimed is disclaimed” for divisional applications has been rejected, decoupling divisional applications from the claims of the parent application.
• The rejection or abandonment of a divisional application has no bearing on the validity of the parent patent[28].
• If a divisional application is filed on the same day as the grant of the original patent application, a divisional application must be duly considered.

These reforms reflect a progressive shift in the Indian patent law practice, clearing the way for innovation with procedural flexibility. The evolving standards for divisional applications not only enhance legal clarity but also foster a more inclusive environment for inventors seeking to protect their intellectual property rights. This trajectory signals that Indian patent jurisprudence is increasingly aligned with international practices, creating an ecosystem conducive to technological advancement and creativity.