The burden of proof is defined in section 101 of the Indian Evidence Act, 1872, (act) thus: “whoever desires any court to give judgment … dependent on the existence of facts which he asserts must prove that those facts exist. When a person is bound to prove the existence of any fact, it is said that the burden of proof lies on that person”. Accordingly, the onus of adducing evidence to prove the facts on which allegations are based lies on the plaintiff. Similarly, the burden of proof in patent infringement litigation lies on the patentee or plaintiff to adduce factual evidence that the patent has been infringed. However, if the subject matter of a patent is a process, and the patentee or person deriving title or interest is able to prove that the infringed product is identical to the product directly obtained by the patented process the burden of proof may shift to the defendant to prove that the process used by him is different from the patented process.
In Farbewerke Hoechst etc v Unichem Laboratories and ors the Bombay High Court held that the burden of proof in the process patent is based on section 106 of the act which provides that “when any fact is especially within the knowledge of any person, the burden of proving that fact is upon him”.
Therefore, if the process by which the product is obtained is especially within the knowledge of the infringer or defendant it is impossible for the plaintiffs to know exactly how the product has been obtained by the defendants. Thus, the burden of proving the process used by the defendant to make the infringing product lies on him.
The burden of proof in case of process patent is also dealt with in section 104A of the Patents Act, 1970, which provides that “In any suit for patent infringement involving a process for obtaining a product, the court may direct the defendant to prove that the process used by him to obtain the product, identical to the product of the patented process, is different from the patented process.” In Communications Component Antenna Inc v ACE Technologies Corp and ors, the Delhi High Court recently held that if the defendant withholds its best and easily obtainable evidence, an adverse inference can be drawn against it. The court stated that “in a patent infringement action, once the plaintiff, prima facie establishes infringement, the onus shifts on the defendants, to disprove the same. The complete silence by the defendants shows that there is, in fact, withholding of relevant and crucial information from the court”.
In another recent case, Shogun Organics Ltd v Gaur Hari Guchhait and ors, the same court further ruled on the burden of proof. Shogun Organics, a company engaged in the research, manufacture, and sale of mosquito repellent applied for a permanent injunction restraining the defendants from infringing its process patent. The patent related to the manufacture of an insecticide. The plaintiffs purchased base material from the defendants but established that, after the grant of the patent the defendants sold their product with the addition of various compounds and content specific to the plaintiff’s patented process. The onus therefore shifted to the defendants to prove that the process adopted by them was different from the patented process.
The defendants had either to disclose their process and highlight the differences from the patented process or to show that the product obtained from the defendant’s process was though its material but had different properties or reactants or ingredients. Both sides relied upon registration of their respective products with the Central Insecticides Board and Registration Committee. The plaintiff tried to show thereby that its patent had novelty and the defendants argued that registration showed that the process was in the public domain. The court held, however, that such registration was irrelevant in patent disputes.
The defendants adduced no evidence. The court drew the adverse inference against them and held the defendants to have infringed the patent.
Ascertaining how the process patent has been infringed without knowing the process of the infringer poses a significant challenge to the patentee. Fortunately, in the case of process patents, the burden of proof shifts to the defendant if the patentee proves that the infringed product is identical to the product directly obtained by the patented process. The law prescribes no particular way to show that two products are identical, but process patent infringement cases show that courts are persuaded by evidence of identical composition and empirical data relating to the products.
Swati Gupta is an associate at LexOrbis.
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