Apple is always looking for the next health feature that they could bring to Apple Watch and this week the US Patent & Trademark Office published a patent application from Apple that relates to a possible future Specialty Apple Watch and system for performing physiological measurements by coupling the watch to the body of a user.

The system describes and focuses on a new "patch system" that could hold an Apple Watch or a part thereof in place in the chest and/or leg areas for monitoring heart activity more accurately.

The system, should it come to market, would be a direct competitor to Polar, the pioneer in this type of health monitoring system. The image below is from Polar's website.

(Click on the image to Enlarge)

Apple notes in their patent background that modern medical devices can be used to measure health parameters of a user or patient. However, many traditional medical devices may be too bulky or expensive to be used during normal daily activities.

The systems and techniques described in this patent may be used to obtain physiological measurements without some of the drawbacks of some traditional medical devices.

Physiological Sensing Patch for Coupling a Device to a Body of a User

Apple's patent relates to a patch for coupling a watch body to a body of a user. The patch can include a patch substrate formed from a flexible material, an adhesive disposed over a first surface of the patch substrate and configured to couple the patch to the body of the user and a watch-mounting component positioned at a second surface of the patch substrate and configured to couple the watch body to the patch. 

The patch can also include a first sensing element that includes a first terminal configured to contact the body of the user at a first location, a first interface element configured to interface with a first watch sensing element of the watch body and a first conduit operably coupling the first terminal to the first interface element.

A smartwatch is typically adapted to only be attached to a wrist of a user. Further, the results of many physiological measurements may be affected by the location of the sensor(s) and/or how the sensor is coupled to a user. For example, a smartwatch may take physiological measurements at the wrist, but the accuracy and/or sensitivity of these measurements may be increased by placing the smartwatch at other locations on a user.

In some instances, the sensitivity and/or accuracy of an electrocardiogram (ECG) measurement on a smartwatch may be increased by placing the smartwatch body closer to a user’s heart and/or measuring the user over an extended time period. However, it can be impractical for a user to hold a smart device to their chest for an extended period of time. Moreover, a user may not be able to hold their smart device in a consistent or stable position for achieving a desirable measurement accuracy. This is where the patch system comes into play.

In some embodiments an ECG sensor can include electrodes positioned on a back surface of the watch body and contact a user’s skin when the smartwatch is worn on a user’s wrist. When the watch body is coupled to other areas of the user, such as a user’s chest, it may be desirable to change the positioning of the electrode contact points with the user. For example, if using the patch to take an ECG measurement at the user’s chest, it may be desirable to increase a distance between the electrodes’ contact points with the user’s body. In this regard, the patch can include a first sensing element that interfaces with a first electrode on the watch body and changes a sensing location of the first electrode on the user’s body.

The first sensing element can include a conductive terminal that contacts the body of the user at a location different from the location of the first electrode. The first sensing element can also include a conductive interface element that contacts the first electrode on the watch body and an electrical conduit that carries signals from the terminal and to the interface element where they are sensed by the first electrode on the watch body.

Apple's patent FIG. 1A & 1C are simply to illustrate the focus device of this invention relates to Apple Watch; FIG. 1B shows a bottom view of the electronic device when disconnected from the patch; FIG. 3A shows an example patch coupled to an electronic device; FIG. 3B shows an exploded view of the example patch shown in FIG. 3A along with the electronic device; FIG. 4 shows an example patch including an optical component.

Apple's patent FIG. 2 below shows an example patch coupling an electronic device to a chest of a user; FIG. 8 shows an example of a patch system that includes multiple patches for physiological sensing.

The first and second electronic devices #803, #805 can establish a communication connection using any suitable technology such as Bluetooth, Wi-Fi, or any other suitable wired or wireless communications protocols. The first and second electronic devices #803, #805 can coordinate physiological sensing activities, transmit data and exchange other information over the communication connection.

The senor system can include optical, electronic and/or other sensors that are configured to measure physiological parameters of a user such as heart rate, temperature, electrical cardiac activity, blood parameters, and so on. In some cases, the sensor system can include sensors such as a photoplethysmography (PPG) sensor, electrocardiogram (ECG) sensor components, and/or the like.

For more details, review Apple's patent application number 20230210392.

Team Members on this Apple Project

• Motohide Hatanaka: Product Design Engineer, Health Products
• Wegene Tadele: HW Tech Lead Apple Watch