There have been many reports of temperature sensors coming to wrist wearable devices. While these reports and rumors have focused on the Apple Watch Series 8 and Samsung Galaxy Watch 5, the latest reading is that body temperature sensors may not be built into either of these watches.
Details of Apple’s temperature sensor patent
Apple’s latest patent, released today, “Temperature gradient detection in portable electronic devices, “provides information on how the company can approach design related to this feature.
This Apple patent was filed on July 21, 2020 and approved on August 9, 2022.
One of the main inventors of this patent is Chad Bossetti, who worked in the Apple Health Technologies division for more than seven years.
The other key person involved in this patent, James Clements is Mechanical R&D Engineering Manager at Apple Health Technologies.
One of the main challenges of integrating a conventional temperature sensor into the wearable device is the amount of bulk (space) the sensor will require.
According to this patent, Apple’s idea is to enclose a temperature detection system, comprising a temperature sensor and a differential temperature probe.
The differential temperature probe comprising a flexible substrate defining two ends.
A first end is thermally coupled to the temperature sensor, and a second end is thermally coupled to an electronic device surface, volume, or component.
The temperature probe is an in-plane thermopile with a series-coupled array of thermocouples extending from the first to the second.
According to Apple, when it comes to wearable devices like the Apple Watch,
“Overall, a portable electronic device incorporating a temperature sensing system as described here can sense the absolute temperature of multiple discrete locations or volumes without requiring multiple discrete temperature sensors. As a result, a portable electronic device can recover and/or reallocate substantial internal volume otherwise conventionally allocated to multiple temperature sensors and can be manufactured at lower cost without sacrificing sensor performance of portable electronic device subsystems that depend on temperature. temperature. . “
Apple Watch and body temperature measurement
In the case of the Apple Watch, a differential temperature probe can be implemented on a thin film flexible substrate which can be routed to a probe location that is substantially smaller than a conventional temperature sensor, or otherwise cannot be thermally coupled to a conventional temperature sensor.
A thin film differential temperature probe may be routed around or through other components within the wearable electronic device to conserve space within the watch body.
In this way, the portable electronic device can be designed and manufactured with fewer positional and/or component constraints.
It may not be necessary to position a temperature sensor at a particular location of the portable electronic device if a differential temperature probe, as described, can be routed to any arbitrary probe location.
The probe locations can be positioned over one or more areas to assess the skin or body temperature of a user or wearer of a portable electronic device.
For example, in some embodiments, a differential temperature probe may position its second end (also referred to as the “distal” end) such that the second end is thermally coupled to a portion of the wearable electronic device case that touches the skin of a user. skin, like the back glass of a smartwatch.
Thanks to these constructions, the portable electronic device can obtain a very precise image and very precise measurement of the user’s skin temperature, which, in turn, can be leveraged for: health or fitness recommendations, health or fitness tracking, and biometric identification.
The idea of a temperature-sensing system goes beyond the Apple Watch
According to the patent document, the temperature sensing system can be operated differently when incorporated into other classes of portable electronic devices.
For example, a smartwatch can take advantage of a temperature sensing system to detect the temperature of a processor and a rear crystal.
In another example, a pair of headphones or wireless headphones can take advantage of a temperature sensing system to detect a temperature of an inner ear of a wearer of these headphones or headphones.
An Apple Pencil’s temperature measurement system can help detect if a user is picking up the stylus.
As for the Samsung Galaxy Watch 5 and skin temperature sensors, the Samsung Unpacked event should give us all the details!