Patent 11913845 was granted and assigned to Temptime Corporation on February, 2024 by the United States Patent and Trademark Office.
A temperature indicator includes a first capacitor configured to change capacitance when exposed to a temperature above a first threshold temperature, a second capacitor configured to change capacitance when exposed to a temperature above a second threshold temperature. The first capacitor is electrically connected to the second capacitor. The second threshold temperature is different than the first threshold temperature. The first capacitor and the second capacitor retain their changed capacitance permanently after they return to a temperature below their respective threshold temperature.