Temperature Gradient Sensing in Portable Electronic Devices

A temperature sensing system for an electronic device, the temperature sensing system comprising:

• a temperature sensor defining an exterior surface;
• and
• a differential temperature probe having a high aspect ratio and formed from a thin-film material, the differential temperature probe comprising:
• a flexible substrate defining:
• a first end thermally coupled to the exterior surface of the temperature sensor;
• a second end separated from the first end by a length of the differential temperature probe;
• and
• a conductive trace defining a conductive path between a pair of leads disposed on the first end, the conductive trace disposed in a serpentine pattern between the first end and the second end, the conductive trace comprising:
• a first set of traces disposed from a first conductive material extending from the first end to the second end;
• and
• a second set of traces disposed from a second conductive material extending from the second end to the first end;
• wherein
• a voltage difference between the pair of leads corresponds to a temperature difference between the exterior surface and the second end of the differential temperature probe.

A portable electronic device, comprising:

• a display;
• a housing that supports the display;
• and
• a temperature sensing system disposed within the housing, the temperature sensing system comprising:
• a temperature sensor;
• and
• a first temperature probe, the first temperature probe comprising:
• a thin-film substrate defining:
• a first end thermally coupled to the temperature sensor;
• and
• a second end thermally coupled to a surface of or within the housing;
• and
• an in-plane thermopile disposed on the thin-film substrate and comprising a conductive trace disposed in a serpentine pattern defined between the first end and the second end to define an array of thermocouples conductively coupled in series;
• wherein
• the in-plane thermopile is conductively coupled to the temperature sensor and is configured to generate a voltage corresponding to a temperature difference between the temperature sensor and the surface.