Infrared sensors for electronic devices

An electronic device, comprising:

• a housing;
• a display mounted in the housing;
• a light sensor that is mounted under an inactive area in the display and that is configured to detect light at a wavelength longer than 3 microns;
• and
• control circuitry configured to measure blackbody light signals at wavelengths longer than 3 microns using the light sensor, wherein the light sensor comprises an array of multiple heat sensing elements and wherein the control circuitry is configured to gather signals from a first subset of the multiple heat sensing elements to make a temperature measurement, and wherein the control circuitry is configured to gather signals from a second subset of the multiple heat sensing elements to make motion detector measurements.

A method of monitoring for external objects within the vicinity of an electronic device, comprising:

• modulating a light source in the electronic device to emit modulated light;
• monitoring for reflections of the emitted modulated light using a mid-infrared light detector, wherein the mid-infrared light detector comprises a bolometer having an array of heat sensing elements;
• and
• detecting motion in the external objects using the array of heat sensing elements, wherein detecting motion in the external objects comprises detecting a hand gesture command from a user's hand using the array of heat sensing elements.