Journal of Intellectual Property Law
Abstract
The doctrine of equivalents began as a measure to protect inventors from unscrupulous copiers who would make substitutions to avoid liability under literal infringement claims. Prosecution history estoppel was established as a guardrail to the doctrine, as a method of bringing some certainty to the scope of patent claims. However, in the Supreme Court’s zeal to contain the doctrine, they over-curbed its efficacy.
In cases that hinged on the doctrine of equivalents, patentees were only successful 21% of the time in district court, and 22% of the time in the federal circuit. A much lower success rate compared to the patentee’s 34% overall win rate in general patent litigation.
This exposes inventors to the risk of unscrupulous copying that the Graver Tank Court warned about. In order to better protect inventors, the solution is that the courts should not apply prosecution history estoppel to the patentee’s response to a first rejection. Examiners are severely overworked and do not spend much time per application, an estimated eighteen hours from receiving an application to the interview.
This proposed change to the prosecution history estoppel rule would allow patentees and patent examiners to get on the same page without the patentee sacrificing future equivalent infringement arguments. In turn, this permits patentees to better protect their invention, which promotes innovation, the principal goal of the patent system.
Recommended Citation
Ian Moore,
Rectifying the Disconnect Between the Policy of the Doctrine of Equivalents and Practice,
32
J. Intell. Prop. L.
79
(2025).
Available at:
https://digitalcommons.law.uga.edu/jipl/vol32/iss2/5