Today the U.S. Patent and Trademark Office officially granted Apple a patent that relates to systems and methods of detecting skin-to-skin contact, and more particularly, to detecting contact between two hands or between two fingers for input in virtual reality or augmented reality environments. While using a VR headset, the actions that could be taken using skin-to-skin contact include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device connected to the host device.

In Apple's patent background they note that many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. In some examples, contact between two different parts of a user's body may be used for input. For example, cameras in a head-mounted display can be used to track movement of fingers to detect a finger in contact with an opposite hand, or to track movement of a finger along an opposite hand surface.

Additionally, or alternatively, a radiofrequency-based system can be used to detect a finger in contact with an opposite hand, or to track movement of a finger along an opposite hand surface. However, camera-based systems and/or radiofrequency-based systems may have difficulty detecting the difference between a finger touching the opposite hand or proximate to without contacting (hovering above) the opposite hand. Additionally, camera-based systems require the finger and opposite hand be in the field of view of the cameras for operation.

Apple's approach is a little different. Apple's invention covers devices and methods of detecting contact between a first body part and a second body part. Sense circuitry can be configured to sense a signal at the sense electrode (e.g., configured to contact the second body part) in response to a drive signal applied to the drive electrode (e.g., configured to contact the first body part).

Processing circuitry can be configured to detect contact in accordance with a determination that one or more criteria are met. The one or more criteria can include a first criterion that is met when an amplitude of the sensed signal exceeds an amplitude threshold and a second criterion that is met when the sensed signal has a non-distorted waveform. Using a robust set of criteria, including an evaluation of the quality of the waveform (e.g., whether it is distorted or not), can improve the disambiguation between a skin-to-skin contact event and a proximity event.

This also relates to devices and methods of detecting a movement gesture using contact between two fingers of the same hand (e.g., to enable one-handed skin-to-skin input gestures).

Sense circuitry can be configured to sense a signal at a sense electrode (e.g., configured to contact a finger of a hand) in response to a drive signal applied to a drive electrode (e.g., configured to contact a different finger of the hand).

Processing circuitry can be configured to detect a movement gesture (e.g., a slide gesture) in accordance with a determination that one or more criteria are met. The one or more criteria can include a first criterion indicative of contact between a first finger and a second finger and a second criterion indicative of movement of the first finger along the second finger.

Apple's patent FIGS. 1A-1B below illustrate an example system for skin-to-skin contact detection. FIG. 1A illustrates a system including two wrist-worn wearable devices 150A, 150B, each including at least one electrode to establish electrical contact between the wearable device and the wearer's skin; FIG. 1B illustrates a backside of wearable device 150 with two electrodes 166A-B.

In some examples, one watch may be used for sensing and processing the sensed signal, and the drive circuitry and electrode can be implemented in another type of device (e.g., a ring). In some examples, one or both devices (e.g., for driving the drive signal and/or sensing the sensed signal) can be implemented in a glove, finger cuff, bracelet, necklace, head-mounted device, necklace, armband, headphones or AirPods.

Apple's patent FIGS. 3A-3B below illustrate a proximity and a contact, respectively, between a first body part and a second body part.

Apple's patent FIGS. 7A-7B illustrate an example system for detection of a skin-to-skin gesture. In particular, FIGS. 7A-7B illustrate a slide gesture between a first finger and a second finger.

Apple notes that in some examples, the first wearable device (#708A) can be disposed at or near (within a threshold distance of) the base of the thumb (#702, e.g., at or near the base of the metacarpal bone). In some examples, the second wearable device (#708B) can be disposed at or near the base of index finger (#704, e.g., at or near the base of the metacarpal bone). In some examples, the first wearable device can be a finger cuff and the second wearable device can be a ring. In some examples, the first and second wearable devices can be implemented as part of a VR glove.

The actions can include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device connected to the host device, answering a telephone call, placing a telephone call, terminating a telephone call, changing the volume or audio settings, storing information related to telephone communications such as addresses, frequently dialed numbers, received calls, missed calls, logging onto a computer or a computer network, permitting authorized individuals access to restricted areas of the computer or computer network, loading a user profile associated with a user's preferred arrangement of the computer desktop, permitting access to web content, launching a particular program, encrypting or decoding a message, and/or the like.

Apple's patent FIG. 10 below illustrates a wearable device in the form of a ring; FIG. 11 is a system block diagram of a ring device; The rest of the patent figures presented below illustrate various gestures a user will be able to make to control as aspect of a display, such as an XR headset display.

Apple further notes that detecting a movement gesture using contact between two fingers of the same hand (e.g., to enable one-handed skin-to-skin input gestures). Sense circuitry can be configured to sense a signal at a sense electrode (e.g., configured to contact a finger of a hand) in response to a drive signal applied to a drive electrode (e.g., configured to contact a different finger of the hand). 

For finer details, review Apple's granted patent US 11625098 B2.