Shrinking Space: Are Narrowed Patent Claims Valid Amendments?


Much emphasis is placed in patent law on the importance of filing for protection as early as possible in the inventive process, in order to obtain necessary rights and benefits. But these applications are by no means set in stone. There is room to amend patent applications, and in India, amendments can be done both while an application is pending, and after a patent has been granted, subject to appropriate permissions from the Controller.

Section 59 of the Indian Patents Act, 1970 (the Act) contains the substantive provisions for amendments to a patent application. Section 59(1) deals with amendment of a pending application, and Section 59(2) deals with amendment after the grant of the patent. Specifically, under Section 59(1), amendments are only permitted if the following requirements are satisfied:

  • The amendment must be by way of disclaimer, correction, or explanation.
  • The amendment has the purpose of incorporation of actual fact.
  • The effect of the amendment ought not be to amend the specification to claim or describe any matter which was not disclosed in substance or shown in the originally filed.
  • The amended claims must fall within the scope of claims as originally filed.

A recent decision of the Delhi High Court in Nippon A&L Inc. v. The Controller of Patents (C.A.(COMM.IPD-PAT) 11/2022, 5 July 2022) shed some judicial light on the interpretation and applicability of this provision, particularly with regard to converting product claims to process claims, which is discussed in this note.


Nippon A&L Inc had filed an application as the Indian national phase entry of the international application for a “copolymer latex” product and its manufacturing process. Importantly, it drafted the claims in a “product by process” format which featured the characteristics of both the product and the manufacturing process. For instance, one of the claims taught “A copolymer latex being obtained by emulsion polymerization….”.

The Indian Patent Office (IPO) raised an objection on the grounds of non-inventive step under Section 2(1)(ja) of the Act, non-patentability under Sections 3(d) and 3(e), and said that the teachings of the claim could not clearly rationalize the scope for which protection was being sought. In response, the applicant submitted an amended set of claims, which were previously defined in ‘product by process’ format to ‘process only’ claims (“A method of emulsion polymerization for obtaining a copolymer latex….”),  by way of providing a clearer and more definite set of claims. However, the Deputy Controller of Patents rejected the patent application for two reasons:

  • The new set of amended claims were beyond the scope of the original claims; and that the amendment from ‘product claims’ to ‘process claims’ was not supported by the description in the patent and therefore, was rejected under Section 59.
  • The amended claims lacked inventive step.

The applicant preferred an appeal before the Delhi High Court, which was the subject matter of the present case. The question before the court was: could the claims as originally filed have been amended into method claims by the Appellant”.

Arguments by the Parties

The claims, originally drafted as ‘product by process’ claims, were amended to “method/process only” claims, in response to objections raised by the IPO. According to Nippon, such an amendment was not beyond the scope of the original claims as the original claims featured both product as well as process claims. In fact, it argued that, by limiting the claims to the process, it has given up a significant portion of the claims, which cannot be held to be covered by Section 59 of the Act.

In its support, it relied upon Article 123 of the European Patent Convention, 1973 (EPC) and the decision of the European Board of Appeals in Konica/Sensitizing [1994] EPOR 142 which stated that “whenever product by process claims are amended and the applicant restricts the claims to only the process, the said amendment can be allowed in terms of Article 123 of EPC.”

Two Indian decisions were also relied upon: the IPO’s decision in Antacor Ltd. & Schweiger, Martin (18 July 2017), where the amendment of ‘product by process’ claims to ‘process only’ claims, under identical circumstances, was deemed permissible to improve the clarity and definitiveness of the claims; and the decision in The Polymer Corporation’s Patent [1972] RPC 39, to argue that “amendments by way of an explanation, which turn ambiguous claims to clearer claims, ought to be permitted.”

On its part, the IPO argued that ‘product by process’ claims are predominantly product claims which are validated for novelty and inventive step in relation to the product rather than the process. Further, it said that if a claim relates to a process, the claim’s scope is defined by the process steps and parameters. It also said that the kernel of ‘product by process’ claims is the product and by converting product-related claims into ‘process’ claims is altering the essence of the claims, which is impermissible under the law. It also argued that permuting a ‘product patent’ into a ‘process patent’ which has not been previously claimed, is not permitted as it broadens the scope of the claims.


The court noted that, as per the objections raised by the Controller while prosecuting the patent application at the IPO, the Controller had specifically asked whether the protection sought covers a method or a product in its entirety. According to the court, this shows that the original application illustrated a process/method in its claims, and importantly, that, by amending the claims, Nippon was itself disclaiming the product portion of the claims.

The Court also observed that the process under claim in the amendment was already mentioned in detail in the original complete specification. For interpretive guidance here, it referred to the Ayyangar Committee Report, whose stated intention was to give broader permissibility for amendments before grant, and restrict the same after grant and advertisement. The court also noted that the invention before and after amendment need not be identical in case of amendment before acceptance, ‘so long as the invention is comprehended within the matter disclosed”. In the light of this, the court decided that the amendment in the present case was within the scope of the patent specification and claims as originally filed.

By restricting the claims to ‘process’ only, the court said that the applicant had narrowed down the scope of the claims, and agreed with the Konika case to hold that the conversion of ‘product by process’ claims to ‘process’ claims was admissible. In this context, the court said that product claims are much broader that process claims; product claims accord patentees with exclusivity for the product itself, irrespective of manufacturing process, whereas process claims restrict monopolistic rights to the method of manufacturing only, and the patentee’s rights will not extend to different processes or even to the product manufactured by the different process.

This decision builds on existing jurisprudence in multiple cases, e.g., AGC Flats Glass Europe SA v. Anand Mahajan, 2009 (41) PTC 207 (DEL) and Sulphur Mills Limited v. Dharamraj Crop Guard Limited (2021) 87 PTC 567, which has held that if an applicant seeks to clarify or narrow down/condense the claims, eventually restricting the scope of invention, the amendment ought to be permitted. The only fact to be considered is that the amended claims must not be inconsistent with the claims filed in the original specification.


With this decision, the Indian position on amendments is reinforced, in that an amendment in a patent application can only extend upto the scope defined by the original claims, and no new matter(s) can be introduced. The Delhi High Court has also said that in conditions where an aspect of a claim or claim-set is sacrificed while another is retained, the corresponding amendment may be allowed. In the present case, where the amendments in claims from “product by process” to “process” unambiguously narrowed the scope of the claims, the court noted that the claimed process had already been stated in the application, and thus the amendments were covered by the patent specification and claims as originally filed. However, even as the court found that the amended claims satisfied the conditions of Section 59(1) of the Act, for objections on the lack of inventive step and non-patentability under sections 3(d) and 3(e) of the Act, the court held that the IPO would have the final say and remanded the matter back to the IPO for re-examination.