Apple has been awarded a patent for a temperature sensor for the Apple Watch, just weeks before the launch of its temperature-aware Apple Watch Series 8.
The patent, called "Temperature Gradient Sensing in Electronic Devices," describes an electronic device housing that includes a temperature sensing system consisting of a temperature sensor and a temperature difference probe. The system works by calculating the difference between the two ends of the probe. One end contacts the surface to be measured, and the other end is connected to a temperature sensor. The voltage difference between the two ends of the probe can then be associated with differential temperature measurements.
Temperature sensors can be placed inside the housing of the electronic device. The first end of the probe can be coupled to a temperature sensor, and the second end of the probe can be coupled to any suitable surface of the electronic device, either internal or external. In this configuration, the temperature sensor can be configured to measure the temperature of any surface or volume touched by the sensing surface at any given sampling time or sampling rate.
The patent goes on to explain in technical detail how the temperature-aware hardware works. Crucially, while the patent covers how a dedicated temperature sensor could be used inside a device to monitor the temperature of components such as a processor, it says the sensor could be used to measure the "absolute temperature" of an external surface, such as skin. Most notably, Apple's patent explicitly mentions that the external probe could be located on the back of the watch and says the system includes a highly accurate absolute temperature sensor.
