On Thursday the US Patent & Trademark Office published a patent application from Apple that relates to possible future Apple Watch Bands, fitness bands, VR glove bands or even fashion bands including embedded micro-machined ultrasonic transducers (MUTs) to detect touch, gestures, physiological health signals, and transfer data between devices, such as an Apple Watch to another Apple Watch or to a Mac, iPad or iPhone. The band would also be able to detect a user's fingerprint (Touch ID). And lastly, the new bands could also assist with virtual reality and mixed reality experiences.  

Apple's patent Abstract states that the invention relates to micro-machined ultrasonic transducers (MUTs) which can be embedded into a flexible Apple Watch band to detect touch, gestures, physiological signals, and transfer data.

In some examples, the MUTs can include a piezoelectric material disposed between two electrodes and coupled to a base material having a plurality of cavities, to support motion of the transducer structure. In some examples, the MUTs can be coupled to multiplexing circuitry to stimulate, configure and control the MUTs.

In some examples, the size, shape, and arrangement of transducers can be changed to improve characteristics associated with ultrasonic transmission. In some examples, the MUT array can be driven (e.g., by the CMOS circuitry) to beamform the transmitted and/or the received ultrasonic waves. In some examples, the one or more MUT arrays can be configured to generate haptic feedback via the flexible band.

Apple's patent FIGS. 1A-D below illustrate example devices in which transducers can be woven into a flexible band to detect touch, gestures, physiological signals, and to transmit data; FIG. 2 illustrates a block diagram of an example computing system #238 that illustrates one implementation of touch, gesture, and physiological signal capture and processing. The computing system can include one or more transducer arrays #230 (e.g., ultrasonic transducer arrays) to measure touch, recognize gestures, and monitor physiological signals from a person contacting a flexible band of the computing system.  

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Apple's patent FIG. 7 above illustrates an Apple Watch comprising micro-machined transducers in the watch band (#714).

In Apple's patent FIGS. 8A and 8B below illustrate an Apple Watch band configured to detect features of a user micro-machined ultrasonic transducer (MUT). MUT arrays can be configured to transmit ultrasonic waves. When the waves "echo" off a surface, reflected ultrasonic waves can be received by the MUT arrays and further processed—this concept can be applied to detect a fingerprint of a user. 

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Apple's patent FIG. 9 above illustrates an example device configured to detect touch. In some examples, touch location and velocity can be detected and tracked by an Apple Watch (device 900) that includes a band (#914).

In some examples, after determining particular features such as the touch location of a finger, transducer array (#930) can be configured to improve detection of a subset of the band surrounding the touch location (e.g., beamform the transducer waves, configure array for reverse beamforming).

In some examples, the touch detection can be performed for a plurality of fingers in rapid sequence and/or simultaneously which could be a user applying swiping gestures, sequences of taps, spatial relationships between one or more objects using a single finger, multiple finger, and/or some combination thereof can be detected. As important is the fact that a fingerprint in contact with the flexible band can be detected (= Touch ID).

Apple's FIG. 10 below is an interesting feature wherein the transducer array in the band could detect user Hand Gestures.  In some examples, the transmission, reception, and processing of ultrasonic waves can be repeated over time to detect changes in position of the hand. For example, the velocity (i.e., both speed and direction) of the hand can be detected. Additionally or alternatively, three or more transducer arrays (e.g., 1030A-C) can be configured to detect a three-dimensional map of the finger.

The use of the transducer array in the band for detecting hand gestures can extend to VR Gloves to enhance XR experiences.

Apple further notes that in some examples, an Apple Watch coupled to a band can comprise transducer arrays configured to transmit towards and receive signals from the wrist of a user. For example, the watch device can be configured to detect physiological signals including blood pressure, heart-rate variability, and/or indications of blood vessel dimensions.

For Apple patent FIG. 14 above, Apple notes that in some examples, signals transmitted between the two or more devices can be configured to carry data. For example, one or more files can be sent between the devices, provided a suitable encoding scheme is selected for data transmission.

For more details, review Apple's patent application number US 20230099288.

Apple Inventors

• Wang Qi: Hardware Engineer
• Jere Charles Harrison: PhD, experience with Micro-Machining, Magnetic MEMS+
• Mia (Mihye) Shin: Engineering Manager
• Yunhan (Ian) Chen: Haptic Hardware Engineer