Proving Infringement of a Process Patent

In one line

Where a process patent is infringed the plaintiff cannot see inside the defendant's factory, so in two situations the court may order the defendant to prove that its process is different.

In the wording a student can write in an exam: section 104A of the Patents Act, 1970 provides that in a suit for infringement where the subject matter of the patent is a process for obtaining a product, the court may direct the defendant to prove that the process used by him to obtain a product identical to the product of the patented process is different from the patented process, in the two cases set out in clauses (a) and (b), and subject to the proviso and to sub-section (2).

The problem it solves

A process is invisible from outside. A plaintiff who suspects that a competitor is using its patented synthesis can buy the competitor's product, analyse it, and prove that it is identical. What the plaintiff cannot do is prove what happened inside the factory.

The ordinary rule of evidence would defeat every process patent. He who asserts must prove. If the plaintiff must prove the defendant's process and cannot see it, the patent is worth nothing.

So the burden is reversed, but only on conditions. A blanket reversal would let any patentee force a competitor to disclose its manufacturing methods on a bare allegation, which would turn the provision into a discovery weapon.

The provision itself

Section 104A(1). In any suit for infringement of a patent, where the subject matter of the patent is 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, if:

(a) the subject matter of the patent is a process for obtaining a new product; or

(b) there is a substantial likelihood that the identical product is made by the process, and the patentee or a person deriving title or interest in the patent from him has been unable through reasonable efforts to determine the process actually used.

The proviso. The patentee, or a person deriving title or interest from him, first proves that the product is identical to the product directly obtained by the patented process.

Section 104A(2). In considering whether a party has discharged the burden imposed by sub-section (1), the court shall not require him to disclose any manufacturing or commercial secrets, if it appears to the court that it would be unreasonable to do so.

Broken down

The gateway is the proviso, and it comes first in practice. Before anything else the patentee must prove that the defendant's product is identical to the product directly obtained by the patented process. Note the word "directly", which is the same limit that section 48(b) uses and chapter 450 works.