Guest Post on India’s First "Doctrine of Equivalents" Case

We bring you a guest post from Nirajan Man Singh, a fifth year law student of the National Academy of Legal Studies and Research (NALSAR),Hyderabad, India.

Niranjan is a prolific reader and writer. Among his various publications and paper presentations includes one at the “The Business and Race Conference” organized by MIT, Boston on 3rd of April, 2007. He is also scheduled to visit the Millstein Center for Corporate Governance and Performance at Yale, Connecticut in November, 2008.

I have to first apologise to Niranjan for the sheer delay in bringing you his guest post. He send me this note several weeks back. This is a pathbreaking case for India, as it is the first one (to the best of my knowledge) that deals with the doctrine of equivalents.

Ravi Kamal Bali v. Kala Tech: A Critique

To permit the imitation of a patent which doesn’t copy every detail would be to convert the patent into a valueless piece of paper. Needless to say, such a limitation would leave room and encourage a copyist to make immaterial changes in the patent that would make the copied matter outside the claim and outside the reach of patent law. The doctrine of equivalence evolved in response to this experience.

As expected, once a person becomes a patent owner he or she gets the exclusive right to sell, manufacture and market the product for the specified period of time, and the others are excluded to do the same. In this case, plaintiff sought damages and an injunction order restraining the defendants from making, using, selling or distributing ‘tamper proof locks’ that fall within the scope of the claims of the Plaintiff’s patent. The burden of proving that the defendants act falls within scope of the plaintiff’s patent claim, either directly or by doctrine of equivalence is always on the plaintiff.

Under the Indian law, the power to pronounce on the validity of patents rests only with the High Courts. So, even if the plaint is originally filed in a District Court, once the defendant pleads invalidity of patents, the matter would be immediately transferred to High Court. Here, the Bombay High Court tried to deduce whether defendants act amounted to induced infringement or contributory infringement or both. As per the facts, one of the defendants was a former employee of the plaintiff and had unrestricted access to every technical details of the patented product and has been immorally assisting other defendants in the manufacture and sale of the infringing material. In order to prevent fraud on the patent, the court applied the doctrine of equivalence. Such is invoked when a patents claim is not literally infringed. The rationale of this doctrine is very simple, if two devices do the same work in substantially the same way and accomplish substantially the same result, then the second device will infringe the first patent, even though they differ in name, form and shape.

The Court emphasized on section 54 of the Indian Patent Act, 1970 and held only the patentee of the main invention is entitled to improve or modify the main invention and claim patent for such or else it would permit anybody to benefit from it by exploiting the main invention. The court opined that a mere carrying forward of an existing product involving change of form, proportion or degree or the substitution of an equivalent is not an invention.

Further, the court held that there should be an honest and full disclosure of facts when a plaintiff seeks an order of ad interim injunction without notice to the defendant, any premeditated false representation will lead to denial of such order. It was also clarified by the court that a mere delay would not disentitle the Plaintiff to the injunction. Here, the plaintiff was aware since June 2004 of the defendants continued infringement, and after a delay of 18 months without any notice to the defendants an application for ad interim injunction was made.

Earlier in order to grant an injunction the court would look on whose favor was a “prima facie” case and “balance of convenience”. At the present, “public interest” and “pricing” are being considered as a measuring tool for granting an injunction in patent matters. In Ravi Kamal Bali, the order for interim injunction was refused as the injunction was sought on an erroneous representation of a material aspect. In addition to this, an interim injunction will not be granted if the patent which has been obtained by the plaintiff is a recent one and there is a serious controversy about the validity of grant of the patent itself.

Finding of equivalence is a determination of fact, proof can be made in any form through testimony of experts skilled in the field or an authoritative document on the subject. The proofs are highly technical in nature and involve a detailed analysis of the scope of claims, and it is crucial that the court understand the issue before granting an injunction order.

It should always be kept in mind that assessment should be based on objective and quantifiable data and should not be on the basis of whim and fancy. The sanctity of “doctrine of equivalence” via-a-vis “injunction” should be retained and maintained.

Shamnad Basheer

Shamnad Basheer

Prof. (Dr.) Shamnad Basheer founded SpicyIP in 2005. He's also the Founder of IDIA, a project to train underprivileged students for admissions to the leading law schools. He served for two years as an expert on the IP global advisory council (GAC) of the World Economic Forum (WEF). In 2015, he received the Infosys Prize in Humanities in 2015 for his work on legal education and on democratising the discourse around intellectual property law and policy. The jury was headed by Nobel laureate, Prof. Amartya Sen. Professional History: After graduating from the NLS, Bangalore Prof. Basheer joined Anand and Anand, one of India’s leading IP firms. He went on to head their telecommunication and technology practice and was rated by the IFLR as a leading technology lawyer. He left for the University of Oxford to pursue post-graduate studies, completing the BCL, MPhil and DPhil as a Wellcome Trust scholar. His first academic appointment was at the George Washington University Law School, where he served as the Frank H Marks Visiting Associate Professor of IP Law. He then relocated to India in 2008 to take up the MHRD Chaired Professorship in IP Law at WB NUJS, a leading Indian law school. Later, he was the Honorary Research Chair of IP Law at Nirma University and also a visiting professor of law at the National Law School (NLS), Bangalore. Prof. Basheer has published widely and his articles have won awards, including those instituted by ATRIP, the Stanford Technology Law Review and CREATe. He was consulted widely by the government, industry, international organisations and civil society on a variety of IP issues. He also served on several government committees.


  1. AvatarAnupam

    I find this post very interesting. It gives a very concise and to the point analysis of doctrine of equivalence and also a suggestion on how Courts should be more careful while granting injunction orders as the matters are technical in nature and without understanding the facts and issues the court’s are granting injunction such as the Cipla case.

  2. AvatarAnonymous

    So you are you trying to say that Indian Courts are not competent? if not then what are the solutions available? Should they just stop giving judgments then? Your analysis of the case is good, but you haven’t provided us with an alternative solution….i do hope to read your answers to my query very soon.

  3. AvatarMishi Choudhary

    The insubstantial differences test is usually the starting point to apply the doctrine of equivalents, but the fulfillment of this standard does not necessarily compel a conclusion of infringement.
    There are constraints placed on courts throughout the world who use Doctrine of Equivalents.These are the
    Four Elements Rule
    Prior art
    Prosecution history estoppel
    Public declaration doctrine

    This kind of analysis requires some expert opinion and not just a legal ruling disregarding factual determinations.


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