In a per curiam decision the Federal Circuit upheld the U.S. District Court for the District of Massachusetts’ holding that certain claims of Exergen Corporation’s U.S. Patent No. 7,787,938 was invalid as being directed to an abstract idea, and thus not infringed by Thermomedics, Inc.

Exergen’s original lawsuit alleged that Thermomedic’s Caregiver non-contact thermometers infringed certain claims of the ‘938 patent, entitled “TEMPORAL ARTERY TEMPERATURE DETECTOR”. Exergen also markets a variety of temporal artery thermometers.

Claim 51, one of the claims asserted in the suit, recites:

A method of detecting human body temperature comprising: measuring temperature of a region of skin of the forehead; and processing the measured temperature to provide a body temperature approximation based on heat flow from an internal body temperature to ambient temperature.

Figure 1 from the ‘938 patent is reproduced here.

The Federal Circuit upheld the district court’s grant of Thermomedic’s motion for summary judgment of invalidity. The district court found that the asserted claims of Exergen’s ‘938 patent was not eligible for patent protection because it merely identified a discoverable relationship between a patient’s skin temperature and the patient’s core temperature. The court elaborated that the asserted claims of the ‘938 patent did not add an “inventive concept” to this “natural relationship”, and was invalid and thus not infringed by Thermomedics. The court acknowledged that although the discovery may have been extremely valuable to the medical community, the asserted claims of the ‘938 patent did not “add enough to qualify as a patent-eligible process applying” the discovery.