Prosecution history estoppel

When Dye Becomes Decisive: Patent Infringement, Equivalence, and Estoppel

A farmer on a tractor ploughing a sunlit field, with a backdrop of green hills and a molecular structure overlay, symbolising agricultural innovation and chemical formulation.

In a patent infringement case, the Delhi High Court denied Crystal Crop Protection’s request for an interim injunction against Safex Chemicals. The dispute in the case centred on a herbicidal formulation containing Clodinafop, Metribuzin, and a dyeing agent. The Court held that the dye was an essential claim element and that Safex’s dye-free products did not infringe, even by equivalence. It also invoked prosecution history estoppel, noting that Crystal’s own claim amendments precluded a broad claim interpretation.

Prosecution History Estoppel applies to trademark cases, confirms the Bombay High Court.

The Bombay High Court recently ruled that the “prosecution history estoppel” principle applies to trademark cases. This means that statements made during the trademark registration process about similarities with other trademarks can be used against the applicant in future infringement lawsuits. The Court also emphasized the importance of disclosing all relevant information, including prosecution history, in trademark lawsuits.

Prosecution History E’stop’pel!

This post was first published on 3rd September, 2014. All of us have experienced times when things don’t work the way we want them to when...

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“Merry Christmas, Christmas patents, Santa Drones, Seminar on Innovation and IP, MSF v. Gilead, Fitness tracker patent dispute, Nokia and Huawei patent license agreement, GCC...

Prosecution History Estoppel

Patent prosecution is an iterative process and it is during this process that the applicant often changes the language of their proposed claims. The doctrine...