Brief Fact Summary. Patentee Johnson & Johnston Associates, Inc. (Plaintiff) brought suit against competitor R.E. Service Co., Inc. (Defendant) for patent infringement of aluminum/steel substrates used in the manufacture of circuit boards.
Synopsis of Rule of Law. In a patent specification, under the doctrine of equivalents, there is no access to any subject matter that is disclosed but not claimed.
Issue. Can a patentee apply the doctrine of equivalents to cover subject matter that was disclosed but not claimed in the specification?
Held. (Per curiam)Â No.Â A patentee may not apply the doctrine of equivalents to cover subject matter that was disclosed but not claimed in the specification.Â The claim requirement presupposes that a patent applicant defines the invention in the claims, not in the specification, since the claims provide the measure of a patentee’s right to exclude infringement.Â Therefore, infringement law compares the accused infringing product with the claims as construed by a court.Â When a patent drafter discloses but fails to claim subject matter, as here, the unclaimed subject matter is dedicated to the public.Â In addition, a patentee cannot narrowly claim an invention, and then after a patent is issued, use the doctrine of equivalents to establish infringement because the specification discloses equivalents.Â Johnston’s (Plaintiff) patent â€˜050 specifically limits the claims to sheets of aluminum, but it does state that other metals, including stainless steel or nickel alloys, may be used.Â Having disclosed the steel substrates but not claimed them, Plaintiff cannot now utilize the doctrine of equivalents to extend the aluminum limitation to encompass steel substrates.Â A patentee who inadvertently fails to claim disclosed subject matter does have a remedy: within two years from the original patent grant, a patentee may file a reissue application to try to enlarge the scope of the original claims to include the unclaimed subject matter.Â Also, a patentee can file a separate application that claims the disclosed subject matter, which is what Plaintiff actually did.Â Regardless, the district court erred as a matter of law in concluding Defendant infringed the â€˜050 patent under the doctrine of equivalents by using a steel substrate.Â Judgment of infringement is therefore reversed.
Concurrence. (Rader, J.)Â There is an alternative reasoning that reconciles the notice function of patent claims with the protective feature of the doctrine of equivalents.Â This simple principle: that the doctrine of equivalents does not capture subject matter that the patent drafter should have reasonably foreseen during the patent application process and, therefore, should have included in the claims.
Discussion. The court sought to encourage competition.Â Otherwise an individual submitting a patent application could cast too wide a net, prior to even anticipating new technology or new uses for a patent, by naming all future possibilities as to that product.Â Allowing someone to cast such a net would stifle someone else with an otherwise â€œoriginalâ€ invention.