6.5.1 Claim construction
Claim construction forms a critical component of patent enforcement and invalidity challenges. Claim construction is a prerequisite for infringement analysis because the claims determine the scope of protection afforded to the patentee. Similarly, only after claims are construed to determine the invention can invalidity analysis proceed.
Unlike the mechanism of a “Markman” hearing in the U.S., there is no separate procedural step for claim construction. Instead, claim construction is handled as part of the trial. Any disputes concerning the construction of claims will be framed as issues during the case management hearing. In the High Court of Delhi Rules Governing Patent Suits, 2022, it has been recommended that parties file a claim-construction brief before the case management hearing to enable courts and parties to assess whether there are any disputes in relation to the claims.102
In the context of India’s predecessor legislation, the Supreme Court of India has held that claims must be given an effective meaning and that the specification and claims must be examined and construed together.103 The Supreme Court followed English precedents when coming to this conclusion.
Under the Patents Act, 1970, the Delhi High Court, in F Hoffmann-La Roche Ltd v. Cipla Ltd,104 held that one must undertake a “purposive construction” of the claims. The Delhi High Court drew inspiration from the concept of purposive construction that was formulated in the seminal English judgment Catnic Components Ltd v. Hill and Smith Ltd105 This principle is captured in the following two dicta in the Catnic Components case:
whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variant would fall outside the monopoly claimed, even though it could have no material effect upon the way the invention worked.
No plausible reason has been advanced why any rational patentee should want to place so narrow a limitation on his invention. On the contrary, to do so would render his monopoly for practical purposes worthless, since any imitator could avoid it and take all the benefit of the invention by the simple expedient of positioning the back plate a degree or two from the exact vertical.106
This principle of purposive construction was streamlined in the form of “Improver” questions in a subsequent judgment in the United Kingdom (U.K.)107 and later approved by the House of Lords.108 However, the U.K. Supreme Court, in Actavis UK Ltd v. Eli Lilly and Co.,109 disagreed with the earlier line of cases. According to the U.K. Supreme Court, this earlier line of case law on purposive construction conflated the issue of claim construction and infringement analysis.
The current standard in the U.K. requires a court to adopt a “normal interpretation” approach. For infringement purposes, according to the U.K. Supreme Court, one must examine whether the infringing device or process infringes the claim as construed by such normal interpretation. If not, the U.K. Supreme Court dictates that a court must thereafter assess whether the claim is infringed by equivalents. It has formulated a test for assessing such equivalents. The U.K. Supreme Court’s judgments in Actavis UK Ltd and subsequently in Icescape Ltd v. Ice-World International BV 110 have clarified that the normal interpretation of claims is also purposive. Such interpretations are purposive because courts are to construe claims as per their ordinary language, in their context (description and drawings) and in the light of the factual background (common general knowledge in the art).
There has been no subsequent judgment in India addressing these jurisprudential developments. However, since even the earlier rulings of the Supreme Court of India and the Delhi High Court were guided by the English precedents, it is expected that Indian courts will take a similar approach to claim construction.