The function of patent law is to enable a patent holder to prohibit a third party from making, using, selling, importing, or otherwise violating their rights with respect to a patented invention. Primarily, patents can be classified into three types: utility patents, design patents, and plant patents. Utility patents refer to patents that are related to domains such as technology, chemistry, and software. Most often than not, utility patent applications consist of detailed drawings and charts. It is also preferable that utility patent applications have a detailed description of the functionality of the patent. Secondly, a design patent refers to patents wherein the visual characteristics of a product are patented. Design patents must be accompanied by a detailed drawing of the product’s design. Lastly, a plant patent refers to patents that are granted to inventors who have asexually reproduced a new variety of plants (other than a tuber propagated plant or a plant found in an uncultivated state). A patent infringement (“infringement”) is a violation of the exclusive rights granted to an inventor, by the third party and is dealt with extensively in both statute and jurisprudence. Patent infringement is broadly classified into direct infringement and indirect infringement. These distinctions are not made by statutory definition, but by practice.
Direct and Indirect Infringement
Direct Infringement is the marketing, sale, or commercial use of an item or invention that performs substantially identical functions to the patented invention. Direct infringement becomes literal infringement when the infringing item is identical (i.e. containing every component in the patent) held in Polaroid Corp v. Eastman Kodak Co. Non-literal infringement (also known as the application of the doctrine of equivalency) involves cases where it is necessary to compare the infringing device or process to the patented invention and determine whether they are sufficiently similar to constitute infringement held in Ravi Kamal Bali v. Kala Tech. Moreover, an inducted infringement occurs when a party attempts to induce another party to infringe a patent by facilitating them to do so. Thus, assistance or aid provided in any manner in order to commit patent infringement can be considered as infringement by inducement.
The Doctrine of Equivalence was recently explained and upheld in the case of FMC CORPORATION & ORS. versus NATCO PHARMA LIMITED FAO(OS) (COMM) 301/2022 vide dated 05-12-22
In this matter the appellants (“FMC”) have filed the aforementioned suit seeking a decree, restraining the respondent (“Natco” )from infringing a patented process/method for the manufacturing/preparation of Chlorantraniliprole (hereafter ‘CTPR’). The patent is in respect of the process or method, as claimed in Indian Patent no.298645.
The Honourable High court of Delhi observed that :
“The doctrine of equivalents is applicable where a product or process is not identical to the claim granted in a patent but its essential elements are sufficiently similar to the patented claim, so as to construe the product or process as infringing the patent.
What constitutes equivalency must be determined against the context of the patent, the prior art, and the particular circumstances of the case. Equivalence, in the patent law, is not the prisoner of a formula and is not an absolute to be considered in a vacuum. It does not require complete identity for every purpose and in every respect. In determining equivalents, things equal to the same thing may not be equal to each other and, by the same token, things for most purposes different may sometimes be equivalents. Consideration must be given to the purpose for which an ingredient is used in a patent, the qualities it has when combined with the other ingredients, and the function which it is intended to perform. An important factor is whether persons reasonably skilled in the art would have known of the interchangeability of an ingredient not contained in the patent with one that was.
The doctrine of equivalents has been accepted in the jurisprudence to protect patent rights from being infringed by infringers using colourable method of making some minor, insubstantial variations to escape the reach of the patent. The doctrine of equivalents, in essence, seeks to address infringers who introduce minor variations as subterfuge to defeat patent rights. The doctrine is applied to ascertain whether there is an infringement by excluding any insubstantial, minor or trivial changes that are designed to deprive the patentee of the benefits of his invention.
The doctrine of equivalents is applicable only in cases where the variation or difference between the product or process and the patented claim is insignificant, insubstantial and not essential to the patented claim. In order to determine whether, on the basis of doctrine of equivalents, a product or process infringes the patent, it is essential to determine the essence and scope of the patent. It is important to understand as to what is the invention that is patented. If the invention is infringed by a product or process, the minor differences in the nonessential trappings of the product or process would be irrelevant.”
It was held that there is no ambiguity in the response of Dr. Nair that the NATCO Process is not equivalent to the process disclosed in the suit patent. It would be a complete misreading of the response if the first sentence is read without reading further explanation. That the results of the reaction using methane sulfonyl chloride, compared to the reaction using thionyl chloride, does not produce the same result, in view of the resultant characteristics of the by-products. That the NATCO Process and the process claimed in the suit patent were not the same because in the NATCO Process, the compound of carboxylic acid is converted to its acid chloride prior to reaction with 2-Amino-5-chloroN, 3-dimethylhenzamide. Thus, the NATCO Process is a two-step process, with the first reaction yielding an acid chloride and the second reaction involves the acid chloride and base (compounds of Formulae 3) to yield CTPR. On the other hand, the suit patent discloses a single reaction, where sulfonyl chloride is added to the mixture of compounds of Formula 2 and Formula 3.