What Infringement Is

In one line

Infringement is doing, in India and without consent, one of the acts section 48 lets the patentee prevent, and the whole question is whether what the defendant does falls inside the claims.

In the wording a student can write in an exam: the Patents Act, 1970 contains no definition of infringement; it is the doing, in India and without the patentee's consent, of an act which by section 48 the patentee has the exclusive right to prevent, and whether an act falls within the patent is decided by construing the claims of the complete specification.

The acts

For a product patent, section 48(a). Making, using, offering for sale, selling, or importing for those purposes, that product in India.

For a process patent, section 48(b). Using the process, and using, offering for sale, selling or importing for those purposes the product obtained directly by that process in India.

Each is a separate act. A person who only imports infringes; so does one who only offers for sale.

Three elements in every case. An act within section 48; done in India; without the consent of the patentee. Chapter 660 works each.

The three questions in an infringement action

One: what does the claim mean? A question of construction, for the court, decided as at the date of the patent through the eyes of a person skilled in the art.

Two: does the defendant's article or process fall within it? A question of fact, decided by comparing the construed claim with what the defendant actually does.

Three: is the claim valid? Almost always raised, by defence under section 107 or by counter-claim under section 64. Chapters 1070 and 1030 work them.

The order matters. A court construes the claim first, without looking at the defendant's product, because construing it with the alleged infringement in view invites a claim shaped to catch the defendant.

How a claim is construed

Read the description first, then the claims. The Supreme Court stated the rule in Biswanath Prasad Radhey Shyam v. Hindustan Metal Industries, (1979) 2 SCC 511, worked in chapter 420: the proper way to construe a specification is to read the description of the invention first and then to see the claims, because a patentee cannot claim more than they desire to patent.

Construe purposively, not literally. The question is what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. A word is not given a meaning the skilled reader would not have given it, and a claim is not defeated by an immaterial variation.

The pith and marrow doctrine. An infringer does not escape by omitting an inessential feature or by substituting an obvious equivalent for one. The court asks whether the defendant has taken the substance of the invention, its pith and marrow.