Diamond v. Diehr Case Brief

Facts of the Case

Certain individuals filed a patent application for a process for molding raw, uncured synthetic rubber into cured precision products. The individuals claimed that their process insured the production of molded articles which are properly cured. Although it is possible by using well-known time, temperature, and cure relationships to calculate by means of an established mathematical equation when to open the molding press and remove the cured product, the individuals argued that the industry had not been able to obtain uniformly accurate cures because the temperature of the press could not be precisely measured, making it difficult to do the necessary computations to determine cure time. The individuals characterized their contribution to the art as residing in the process of constantly measuring the actual temperature inside the mold, with these temperature measurements being automatically fed into a computer which recalculates the cure time by use of the mathematical equation and ultimately signals a device to open the press at the correct moment. Concluding that the individuals’ claims defined and sought protection of a computer program, the patent examiner rejected those claims on the sole ground that they were drawn to nonstatutory subject matter under, which provides for the issuance of patents to whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. The Patent and Trademark Office Board of Appeals agreed with the examiner, but the United States Court of Customs and Patent Appeals reversed, noting that a claim drawn to subject matter otherwise statutory does not become nonstatutory because a computer is involved.


Was the California law prohibiting the sale or transportation of certain avocados within its borders constitutionally valid?


Yes. In a 5-to-4 decision, the court held that a machine which transforms materials physically under the control of a programmed computer is patentable. In addition, and without overruling the earlier Gottschalk v. Benson decision holding that a mathematical procedure cannot be patented, the majority in Diehr said the Benson decision did not render all computer programs unpatentable, contrary to what Justice John Paul Stevens argued in his strong dissenting opinion in Diehr. The Diehr court left undecided the question of whether computer programs standing by themselves could ever be patentable. Immediately following the Diehr ruling, software patent applications began flowing into the Patent Office in a steady stream that remains undiminished today. (Thirteen years later, the Court of Appeals for the Federal Circuit, in In re Alappat, ruled that virtually all computer programs are patentable.)

Case Information

Citation: 450 US 175 (1981)
Argued: Oct 14, 1980
Decided: Mar 3, 1981
Case Brief: 1981