Diamond v Diehr

Facts

• Diehr invented an improved process for molding raw synthetic rubber into cured products
• The process used temperature sensors in the mold and a computer running the Arrhenius equation to continuously recalculate optimal cure time
• When the calculation indicated the rubber was cured, the computer opened the mold automatically
• Prior methods used fixed cure times, leading to under-cured or over-cured products
• The Patent Office rejected the application, reasoning that the only novel element was the use of a computer program (mathematical algorithm)
• The Court of Customs and Patent Appeals reversed; the Commissioner (Diamond) appealed to the Supreme Court

Issues

1. Whether a process for curing rubber that incorporates a computer program running a mathematical equation is patentable subject matter under 35 USC §101
2. Whether the presence of a mathematical algorithm within a claim automatically renders it unpatentable

Held

• The claim is for a process of curing rubber, not for the mathematical formula itself
• A claim must be considered as a whole; the presence of a mathematical algorithm does not render the entire claim unpatentable
• The process produces a useful, concrete, tangible result (properly cured rubber)
• The algorithm is applied in a specific manner to achieve an industrial result, not claimed in the abstract
• The patent is valid; the PTO's rejection reversed

Ratio Decidendi

Section 101 is construed broadly. A process is not unpatentable simply because it includes a step involving a mathematical formula or computer program. The inquiry is whether the claim, taken as a whole, recites a process with a practical application producing a tangible, useful result. Mathematical algorithms alone are not patentable, but their application within a physical process that transforms matter is.