Apple has been granted a patent for a temperature sensor for the Apple Watch Series 8 with body temperature sensing a few weeks before the launch.
The patent, titled “Temperature Gradient Sensing in Electronic Devices,” depicts an electronic device enclosure that includes a temperature sensor and a temperature difference probe as a temperature sensing system. The system works by calculating the difference between the two ends of the probe. One end touches the surface to be measured and the other end is connected to the temperature sensor. The voltage difference between the two ends of the probe can then be correlated with a differential temperature measurement.
The temperature sensor can be placed inside the electronics housing. The first end of the probe can be coupled to the temperature sensor and the second end of the probe can be coupled to any suitable surface of the electronic device, either inside or outside. In this configuration, the temperature sensor can be configured to measure the temperature of any surface or volume contacted by the sensing surface at any given sampling time or sampling rate.
The patent goes on to explain in technical detail how the temperature sensing hardware works. Crucially, while the patent covers how a dedicated temperature sensor can be used inside a device to monitor the temperature of components such as the processor, it says the sensor can be used to measure the “absolute temperature” of an external surface such as skin. Most notably, Apple explicitly mentions in the patent that the location of the external probe can be located on the back of the watch, and says the system includes a high-precision and highly accurate absolute temperature sensor.
The patent outlines several potential shapes and arrangements for the temperature sensor, with one of the more striking designs being a cross-shaped temperature probe. According to Apple analyst Ming-Chi Kuo, Apple originally intended to offer body temperature measurement in the Apple Watch Series 7 model, but shelved that plan after the company developed a body temperature algorithm that failed to meet requirements before the device entered the engineering verification testing (EVT) phase last year.
