PATENT DOCUMENT

Publication Number: US-11755107-B1
Application Number: US-202017021945-A
Country: US
Kind Code: B1

Title: Finger devices with proximity sensors

Abstract:
A system may include one or more finger devices that gather input from a user&#39;s fingers. The system may include control circuitry that sends control signals to an electronic device based on the input gathered with the finger devices. A finger device may include one or more proximity sensors that measure a distance to the user&#39;s finger. The proximity sensor may be a self-mixing optical proximity sensor having a laser and photodiode. The proximity sensor may have submicron resolution and may be configured to detect very small movements of the finger as finger pad is moved around by a thumb finger, by a surface, and/or by other finger movements. The proximity sensor may measure changes in distance between the proximity sensor and a flexible membrane that rests against a side portion of the user&#39;s finger.

Claims:
What is claimed is: 
     
       1. A finger device configured to be worn on a finger of a user, comprising:
 a housing configured to be mounted on the finger; 
 a flexible membrane coupled to the housing that rests against a side portion of the finger and that moves in response to movement of the finger; and 
 a self-mixing optical sensor that measures changes in a distance between the self-mixing optical sensor and the flexible membrane. 
 
     
     
       2. The finger device defined in  claim 1  wherein the self-mixing optical sensor comprises a laser and an integrated photodiode. 
     
     
       3. The finger device defined in  claim 2  further comprising control circuitry that sends control signals to an electronic device based on the changes in the distance. 
     
     
       4. The finger device defined in  claim 3  wherein the control circuitry modulates a drive current applied to the laser. 
     
     
       5. The finger device defined in  claim 1  wherein the self-mixing optical sensor has submicron resolution. 
     
     
       6. A finger device configured to be worn on a finger of a user, comprising:
 a housing configured to be coupled to the finger without covering a lower finger pad surface of the finger; 
 a flexible membrane configured to rest against a side of the finger; 
 a proximity sensor coupled to the housing and separated from the flexible membrane by a cavity, wherein the proximity sensor measures changes in a distance separating the proximity sensor from the flexible membrane; and 
 control circuitry configured to gather input from the proximity sensor as the finger moves. 
 
     
     
       7. The finger device defined in  claim 6  wherein the proximity sensor comprises a capacitive proximity sensor. 
     
     
       8. The finger device defined in  claim 6  wherein the proximity sensor comprises a self-mixing interferometric optical proximity sensor. 
     
     
       9. The finger device defined in  claim 8  wherein the self-mixing interferometric optical proximity sensor comprises a vertical cavity surface emitting laser. 
     
     
       10. The finger device defined in  claim 9  wherein the self-mixing interferometric optical proximity sensor comprises a photodiode and wherein the control circuitry includes a drive circuit configured to modulate the vertical cavity surface emitting laser and includes a sense circuit configured to use the photodiode to measure corresponding self-mixing fluctuations in output light intensity from the vertical cavity surface emitting laser. 
     
     
       11. The finger device defined in  claim 10  wherein the vertical cavity surface emitting laser comprises a laser cavity and wherein the photodiode is integrated in the laser cavity. 
     
     
       12. The finger device defined in  claim 10  wherein the photodiode forms a ring around the vertical cavity surface emitting laser. 
     
     
       13. The finger device defined in  claim 10  wherein the vertical cavity surface emitting laser is stacked on top of the photodiode. 
     
     
       14. The finger device defined in  claim 6  wherein the proximity sensor is one of multiple proximity sensors that measure movement of the finger as the lower finger pad surface is moved by a thumb finger. 
     
     
       15. The finger device defined in  claim 6  wherein the proximity sensor is one of multiple proximity sensors that measure movement of the finger as the lower finger pad surface is moved by a surface. 
     
     
       16. A finger device configured to be worn on a finger of a user, comprising:
 a housing having sidewall portions that extend down first and second sides of the finger and that leave the finger pad exposed; 
 a flexible membrane that rests against the first side of the finger and that moves in response to movement of the finger pad; 
 a distance sensor separated from the flexible membrane by a cavity, wherein the distance sensor measures a distance separating the distance sensor from the flexible membrane; and 
 control circuitry that sends control signals to an electronic device based on the distance. 
 
     
     
       17. The finger device defined in  claim 16  wherein the distance sensor comprises a self-mixing optical distance sensor. 
     
     
       18. The finger device defined in  claim 17  wherein the self-mixing optical distance sensor comprises a vertical cavity surface emitting laser. 
     
     
       19. The finger device defined in  claim 18  wherein the self-mixing optical distance sensor comprises a resonant cavity photodiode. 
     
     
       20. The finger device defined in  claim 16  further comprising:
 an additional flexible membrane that rests against the second side of the finger and that moves in response to movement of the finger pad; and 
 an additional distance sensor that measures an additional distance to the additional flexible membrane, wherein the control circuitry uses the distance and the additional distance to detect front-to-back and side-to-side movements of the finger pad.

Description:
This application claims the benefit of provisional patent application No. 62/904,540, filed Sep. 23, 2019, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, to sensors for finger-mounted electronic devices. 
     BACKGROUND 
     Electronic devices such as computers can be controlled using computer mice and other input accessories. In virtual reality systems, force-feedback gloves can be used to control virtual objects. Cellular telephones may have touch screen displays and vibrators that are used to create haptic feedback in response to touch input. 
     Devices such as these may not be convenient for a user, may be cumbersome or uncomfortable, or may provide inadequate feedback. 
     SUMMARY 
     A system may include one or more finger devices that gather input from a user&#39;s fingers. The system may include control circuitry that sends control signals to an electronic device based on the input gathered with the finger devices. 
     A finger device may include one or more proximity sensors that measure a distance to the user&#39;s finger. The proximity sensor may be an optical proximity sensor such as a self-mixing interferometric optical proximity sensor having a laser and photodiode. The proximity sensor may have submicron resolution and may be configured to detect very small movements of the user&#39;s finger skin as the finger pad is moved around by a thumb finger, by a surface, and/or by other finger movements. The proximity sensor may measure changes in distance between the proximity sensor and a flexible membrane that rests against a side portion of the user&#39;s finger. 
     A self-mixing proximity sensor may have a coherent or partially coherent source of electromagnetic radiation. The source of radiation may, for example, be a coherent light source such as an infrared vertical cavity surface-emitting laser, a quantum cascade laser, or other laser. The self-mixing proximity sensor may also have a light detector such as a photodiode and/or other electromagnetic-radiation-sensitive element. The photodiode may be stacked with the laser and/or may be an intra-cavity photodiode that is located within the laser cavity. 
     The control circuitry can modulate the laser bias current signal to produce a target distance measurement corresponding to an absolute distance between the self-mixing proximity sensor and the user&#39;s finger (or a flexible membrane that rests against the user&#39;s finger). This modulation can enable the detection of the relative displacement of the user&#39;s finger (or a flexible membrane resting against the user&#39;s finger). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an illustrative system with a finger device in accordance with an embodiment. 
         FIG.  2    is a top view of an illustrative finger of a user on which a finger device has been placed in accordance with an embodiment. 
         FIG.  3    is a cross-sectional side view of an illustrative finger device on the finger of a user in accordance with an embodiment. 
         FIG.  4    is a top view of an illustrative finger device with displacement sensors in accordance with an embodiment. 
         FIG.  5    is a perspective view of an illustrative finger device measuring movement of a finger as the user contacts the finger with another finger in accordance with an embodiment. 
         FIG.  6    is a perspective view of an illustrative finger device measuring movement of a finger as the finger contacts a surface in accordance with an embodiment. 
         FIGS.  7 ,  8 , and  9    are top views of a finger making illustrative finger movements that may be detected with a finger device in accordance with embodiments. 
         FIG.  10    is a top view of an illustrative finger device being used to detect an adjacent finger in accordance with an embodiment. 
         FIG.  11    is a perspective view of an illustrative finger device being used to detect input on the side of the finger device in accordance with an embodiment. 
         FIG.  12    is a perspective view of an illustrative finger device being used to detect input on an upper portion of the finger device in accordance with an embodiment. 
         FIG.  13    is a perspective view of an illustrative finger device being used to detect input as the user holds an object in accordance with an embodiment. 
         FIG.  14    is a perspective view of an illustrative finger device being used to detect a finger curling movement in accordance with an embodiment. 
         FIG.  15    is a cross-sectional side view of an illustrative self-mixing proximity sensor in accordance with an embodiment. 
         FIG.  16    is a circuit diagram of self-mixing proximity sensor circuitry in accordance with an embodiment. 
         FIGS.  17 ,  18 , and  19    are side views of illustrative laser and photodiode configurations for a self-mixing proximity sensor in accordance with embodiments. 
         FIG.  20    is a cross-sectional side view of an illustrative finger device with proximity sensors that measure distances to flexible membranes that rest against side portions of a finger in accordance with an embodiment. 
         FIGS.  21 ,  22 ,  23 ,  24 , and  25    are top views of illustrative finger devices with different numbers and locations of proximity sensors in accordance with embodiments. 
         FIG.  26    is a perspective view of an illustrative finger device having proximity sensors on opposing sides of a sidewall structure in accordance with an embodiment. 
         FIG.  27    is a perspective view of an illustrative finger device having proximity sensors located on sidewall structures in accordance with an embodiment. 
         FIG.  28    is a cross-sectional side view of an illustrative finger device having proximity sensors on a upper portion of the finger device in accordance with an embodiment. 
         FIG.  29    is a perspective view of an illustrative finger device having housing that covers most of the tip of the user&#39;s finger and having proximity sensors in accordance with an embodiment. 
         FIG.  30    is a side view of an illustrative finger device having a side housing portion that extends down a back end of a fingertip and having proximity sensors in accordance with an embodiment. 
         FIG.  31    is a side view of an illustrative finger device having a side housing portion that extends down a back end of a fingertip and having proximity sensors at different heights along the side of the finger accordance with an embodiment. 
         FIG.  32    is a side view of an illustrative finger device having a side housing portion that curves away from a back end of a fingertip in accordance with an embodiment. 
         FIG.  33    is a cross-sectional side view of an illustrative finger device having a strap in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices that are configured to be mounted on the body of a user may be used to gather user input and to provide a user with output. For example, electronic devices that are configured to be worn on one or more of a user&#39;s fingers, which are sometimes referred to as finger devices or finger-mounted devices, may be used to gather user input and to supply output. A finger device may, as an example, include an inertial measurement unit with an accelerometer for gathering information on finger motions such as finger taps or free-space finger gestures, may include proximity sensors such as self-mixing interferometric optical proximity sensors for measuring small changes in distance to the finger surface as the finger moves, may include force sensors for gathering information on normal and shear forces in the finger device and the user&#39;s finger, and may include other sensors for gathering information on the interactions between the finger device (and the user&#39;s finger on which the device is mounted) and the surrounding environment. The finger device may include a haptic output device to provide the user&#39;s finger with haptic output and may include other output components. 
     One or more finger devices may gather user input from a user. The user may use finger devices in operating a virtual reality or mixed reality device (e.g., head-mounted equipment such as glasses, goggles, a helmet, or other device with a display) and/or in operating other equipment such as desktop computers, laptop computers, tablet computers, and other electronic devices. During operation, the finger devices may gather user input such as information on interactions between the finger device(s) and the surrounding environment (e.g., interactions between a user&#39;s fingers and the environment, including finger motions and other interactions associated with virtual content displayed for a user). The user input may be used in controlling visual output on the display. Corresponding haptic output may be provided to the user&#39;s fingers using the finger devices. Haptic output may be used, for example, to provide the fingers of a user with a desired texture sensation as a user is touching a real object or as a user is touching a virtual object. Haptic output can also be used to create detents and other haptic effects. 
     Finger devices can be worn on any or all of a user&#39;s fingers (e.g., the index finger, the index finger and thumb, three of a user&#39;s fingers on one of the user&#39;s hands, some or all fingers on both hands, etc.). To enhance the sensitivity of a user&#39;s touch as the user interacts with surrounding objects, finger devices may have inverted U shapes or other configurations that allow the finger devices to be worn over the top and sides of a user&#39;s finger tips while leaving the user&#39;s finger pads exposed. This allows a user to touch objects with the finger pad portions of the user&#39;s fingers during use. If desired, finger devices may be worn over knuckles on a user&#39;s finger, between knuckles, and/or on other portions of a user&#39;s finger. The use of finger devices on a user&#39;s finger tips is sometimes described herein as an example. 
     Users can use the finger devices to interact with any suitable electronic equipment. For example, a user may use one or more finger devices to interact with a virtual reality or mixed reality system (e.g., a head-mounted device with a display), to supply input to a desktop computer, tablet computer, cellular telephone, watch, ear buds, or other accessory, or to interact with other electronic equipment. 
       FIG.  1    is a schematic diagram of an illustrative system of the type that may include one or more finger devices. As shown in  FIG.  1   , system  8  may include electronic device(s) such as finger device(s)  10  and other electronic device(s)  24 . Each finger device  10  may be worn on a finger of a user&#39;s hand. Additional electronic devices in system  8  such as devices  24  may include devices such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a desktop computer (e.g., a display on a stand with an integrated computer processor and other computer circuitry), a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a head-mounted device such as glasses, goggles, a helmet, or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a remote control, a navigation device, an embedded system such as a system in which equipment is mounted in a kiosk, in an automobile, airplane, or other vehicle, a removable external case for electronic equipment, a strap, a wrist band or head band, a removable cover for a device, a case or bag that has straps or that has other structures to receive and carry electronic equipment and other items, a necklace or arm band, a wallet, sleeve, pocket, or other structure into which electronic equipment or other items may be inserted, part of a chair, sofa, or other seating (e.g., cushions or other seating structures), part of an item of clothing or other wearable item (e.g., a hat, belt, wrist band, headband, sock, glove, shirt, pants, etc.), or equipment that implements the functionality of two or more of these devices. 
     With one illustrative configuration, which may sometimes be described herein as an example, device  10  is a finger-mounted device having a finger-mounted housing with a U-shaped body that grasps a user&#39;s finger or a finger-mounted housing with other shapes configured to rest against a user&#39;s finger and device(s)  24  is a cellular telephone, tablet computer, laptop computer, wristwatch device, head-mounted device, a device with a speaker, or other electronic device (e.g., a device with a display, audio components, and/or other output components). A finger device with a U-shaped housing may have opposing left and right sides that are configured to receive a user&#39;s finger and a top housing portion that couples the left and right sides and that overlaps the user&#39;s fingernail. 
     Devices  10  and  24  may include control circuitry  12  and  26 . Control circuitry  12  and  26  may include storage and processing circuitry for supporting the operation of system  8 . The storage and processing circuitry may include storage such as nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  12  and  26  may be used to gather input from sensors and other input devices and may be used to control output devices. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communications circuits, power management units, audio chips, application specific integrated circuits, etc. 
     To support communications between devices  10  and  24  and/or to support communications between equipment in system  8  and external electronic equipment, control circuitry  12  may communicate using communications circuitry  14  and/or control circuitry  26  may communicate using communications circuitry  28 . Circuitry  14  and/or  28  may include antennas, radio-frequency transceiver circuitry, and other wireless communications circuitry and/or wired communications circuitry. Circuitry  14  and/or  26 , which may sometimes be referred to as control circuitry and/or control and communications circuitry, may, for example, support bidirectional wireless communications between devices  10  and  24  over wireless link  38  (e.g., a wireless local area network link, a near-field communications link, or other suitable wired or wireless communications link (e.g., a Bluetooth® link, a WiFi® link, a 60 GHz link or other millimeter wave link, etc.). Devices  10  and  24  may also include power circuits for transmitting and/or receiving wired and/or wireless power and may include batteries. In configurations in which wireless power transfer is supported between devices  10  and  24 , in-band wireless communications may be supported using inductive power transfer coils (as an example). 
     Devices  10  and  24  may include input-output devices such as devices  16  and  30 . Input-output devices  16  and/or  30  may be used in gathering user input, in gathering information on the environment surrounding the user, and/or in providing a user with output. Devices  16  may include sensors  18  and devices  24  may include sensors  32 . Sensors  18  and/or  32  may include proximity sensors (e.g., self-mixing optical proximity sensors), force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors such as microphones, touch and/or proximity sensors such as capacitive sensors, optical sensors such as optical sensors that emit and detect light, ultrasonic sensors (e.g., ultrasonic sensors for tracking device orientation and location and/or for detecting user input such as finger input), and/or other touch sensors and/or proximity sensors, monochromatic and color ambient light sensors, image sensors, sensors for detecting position, orientation, and/or motion (e.g., accelerometers, magnetic sensors such as compass sensors, gyroscopes, and/or inertial measurement units that contain some or all of these sensors), muscle activity sensors (EMG) for detecting finger actions, radio-frequency sensors, depth sensors (e.g., structured light sensors and/or depth sensors based on stereo imaging devices), optical sensors such as self-mixing sensors and light detection and ranging (lidar) sensors that gather time-of-flight measurements, optical sensors such as visual odometry sensors that gather position and/or orientation information using images gathered with digital image sensors in cameras, gaze tracking sensors, visible light and/or infrared cameras having digital image sensors, humidity sensors, moisture sensors, and/or other sensors. In some arrangements, devices  10  and/or  24  may use sensors  18  and/or  32  and/or other input-output devices  16  and/or  30  to gather user input (e.g., buttons may be used to gather button press input, touch sensors overlapping displays can be used for gathering user touch screen input, touch pads may be used in gathering touch input, microphones may be used for gathering audio input, accelerometers may be used in monitoring when a finger contacts an input surface and may therefore be used to gather finger press input, etc.). If desired, device  10  and/or device  24  may include rotating buttons (e.g., a crown mechanism on a watch or finger device or other suitable rotary button that rotates and that optionally can be depressed to select items of interest). Alphanumeric keys and/or other buttons may be included in devices  16  and/or  30 . In some configurations, sensors  18  may include joysticks, roller balls, optical sensors (e.g., lasers that emit light and image sensors that track motion by monitoring and analyzing changings in the speckle patterns and other information associated with surfaces illuminated with the emitted light as device  10  is moved relative to those surfaces), fingerprint sensors, and/or other sensing circuitry. Radio-frequency tracking devices may be included in sensors  18  to detect location, orientation, and/or range. Beacons (e.g., radio-frequency beacons) may be used to emit radio-frequency signals at different locations in a user&#39;s environment (e.g., at one or more registered locations in a user&#39;s home or office). Radio-frequency beacon signals can be analyzed by devices  10  and/or  24  to help determine the location and position of devices  10  and/or  24  relative to the beacons. If desired, devices  10  and/or  24  may include beacons. Frequency strength (received signal strength information), beacon orientation, time-of-flight information, and/or other radio-frequency information may be used in determining orientation and position information. At some frequencies (e.g., lower frequencies such as frequencies below 10 GHz), signal strength information may be used, whereas at other frequencies (e.g., higher frequencies such as frequencies above 10 GHz), indoor radar schemes may be used). If desired, light-based beacons, ultrasonic beacons, and/or other beacon devices may be used in system  8  in addition to or instead of using radio-frequency beacons and/or radio-frequency radar technology. 
     Devices  16  and/or  30  may include haptic output devices  20  and/or  34 . Haptic output devices  20  and/or  34  can produce motion that is sensed by the user (e.g., through the user&#39;s fingertips). Haptic output devices  20  and/or  34  may include actuators such as electromagnetic actuators, motors, piezoelectric actuators, electroactive polymer actuators, vibrators, linear actuators (e.g., linear resonant actuators), rotational actuators, actuators that bend bendable members, actuator devices that create and/or control repulsive and/or attractive forces between devices  10  and/or  24  (e.g., components for creating electrostatic repulsion and/or attraction such as electrodes, components for producing ultrasonic output such as ultrasonic transducers, components for producing magnetic interactions such as electromagnets for producing direct-current and/or alternating-current magnetic fields, permanent magnets, magnetic materials such as iron or ferrite, and/or other circuitry for producing repulsive and/or attractive forces between devices  10  and/or  24 ). In some situations, actuators for creating forces in device  10  may be used in squeezing a user&#39;s finger and/or otherwise directly interacting with a user&#39;s finger pulp. In other situations, these components may be used to interact with each other (e.g., by creating a dynamically adjustable electromagnetic repulsion and/or attraction force between a pair of devices  10  and/or between device(s)  10  and device(s)  24  using electromagnets). 
     If desired, input-output devices  16  and/or  30  may include other devices  22  and/or  36  such as displays (e.g., in device  24  to display images for a user), status indicator lights (e.g., a light-emitting diode in device  10  and/or  24  that serves as a power indicator, and other light-based output devices), speakers and other audio output devices, electromagnets, permanent magnets, structures formed from magnetic material (e.g., iron bars or other ferromagnetic members that are attracted to magnets such as electromagnets and/or permanent magnets), batteries, etc. Devices  10  and/or  24  may also include power transmitting and/or receiving circuits configured to transmit and/or receive wired and/or wireless power signals. 
       FIG.  2    is a top view of a user&#39;s finger (finger  40 ) and an illustrative finger-mounted device  10 . As shown in  FIG.  2   , device  10  may be formed from a finger-mounted unit that is mounted on or near the tip of finger  40  (e.g., partly or completely overlapping fingernail  42 ). If desired, device  10  may be worn elsewhere on a user&#39;s fingers such as over a knuckle, between knuckles, etc. Configurations in which a device such as device  10  is worn between fingers  40  may also be used. 
     A user may wear one or more of devices  10  simultaneously. For example, a user may wear a single one of devices  10  on the user&#39;s ring finger or index finger. As another example, a user may wear a first device  10  on the user&#39;s thumb, a second device  10  on the user&#39;s index finger, and an optional third device  10  on the user&#39;s middle finger. Arrangements in which devices  10  are worn on other fingers and/or all fingers of one or both hands of a user may also be used. 
     Control circuitry  12  (and, if desired, communications circuitry  14  and/or input-output devices  16 ) may be contained entirely within device  10  (e.g., in a housing for a fingertip-mounted unit) and/or may include circuitry that is coupled to a fingertip structure (e.g., by wires from an associated wrist band, glove, fingerless glove, etc.). Configurations in which devices  10  have bodies that are mounted on individual user fingertips are sometimes described herein as an example. 
       FIG.  3    is a cross-sectional side view of an illustrative finger device (finger-mounted device)  10  showing illustrative mounting locations  46  for electrical components (e.g., control circuitry  12 , communications circuitry  14 , and/or input-output devices  16  such as sensors  18 , haptic output devices  20 , and/or other devices  22 ) within and/or on the surface(s) of finger device housing  44 . These components may, if desired, be incorporated into other portions of housing  44 . 
     As shown in  FIG.  3   , housing  44  may have a U shape (e.g., housing  44  may be a U-shaped housing structure that faces downwardly and covers the upper surface of the tip of user finger  40  and fingernail  42 ). During operation, a user may press against structures such as structure  50 . As the bottom of finger  40  (e.g., finger pulp  40 P) presses against surface  48  of structure  50 , the user&#39;s finger may compress and force portions of the finger outwardly against the sidewall portions of housing  44  (e.g., for sensing by force sensors or other sensors mounted to the side portions of housing  44 ). Lateral movement of finger  40  in the X-Y plane may also be sensed using force sensors or other sensors on the sidewalls of housing  44  or other portions of housing  44  (e.g., because lateral movement will tend to press portions of finger  40  against some sensors more than others and/or will create shear forces that are measured by force sensors that are configured to sense shear forces). 
     Ultrasonic sensors, optical sensors, inertial measurement units, strain gauges and other force sensors, radio-frequency sensors, and/or other sensors may be used in gathering sensor measurements indicative of the activities of finger  40 . If desired, these sensors may also be used in mapping the contours of three-dimensional objects (e.g., by time-of-flight measurements and/or other measurements). For example, an ultrasonic sensor such as a two-dimensional image sensor or an ultrasonic sensor with a single ultrasonic transducer element may emit free-space ultrasonic sound signals that are received and processed after reflecting off of external objects. This allows a three-dimensional ultrasonic map to be generated indicating the shapes and locations of the external objects. 
     In some configurations, finger activity information (position, movement, orientation, etc.) may be gathered using sensors that are mounted in external electronic equipment (e.g., in a computer or other desktop device, in a head-mounted device or other wearable device, and/or in other electronic device  24  that is separate from device  10 ). For example, optical sensors such as images sensors that are separate from devices  10  may be used in monitoring devices  10  to determine their position, movement, and/or orientation. If desired, devices  10  may include passive and/or active optical registration features to assist an image sensor in device  24  in tracking the position, orientation, and/or motion of device  10 . For example, devices  10  may include light-emitting devices such as light-emitting diodes and/or lasers. The light-emitting devices may include light-emitting diodes, lasers (e.g., laser diodes, vertical cavity surface-emitting lasers, etc.), or other light sources and may operate at visible wavelengths, ultraviolet wavelengths, and/or infrared wavelengths. The light-emitting devices may be arranged in an asymmetric pattern on housing  44  and may emit light that is detected by an image sensor, depth sensor, and/or other light-based tracking sensor circuitry in device  24  (e.g., a head-mounted device, desktop computer, stand-alone camera-based monitoring systems, and/or other electrical equipment with an image sensor or other tracking sensor circuitry). By processing the received patterned of emitted light, device  24  can determine the position, orientation, and/or motion of device  10 . If desired, the light-emitting devices can be removable and/or customizable (e.g., a user can customize the location and type of light-emitting devices). 
     Tracking can also be performed that involves extrapolating from a known body part orientation (e.g., a finger orientation) to produce orientation information on other body parts (e.g., wrist and/or arm orientation estimated using inverse kinematics). Visual odometry sensors may, if desired, be included in devices  10 . These sensors may include image sensors that gather frames of image data of the surroundings of devices  10  and may be used in measuring position, orientation, and/or motion from the frame of image data. Lidar, ultrasonic sensors oriented in multiple directions, radio-frequency tracking sensors, and/or other finger device tracking arrangements may be used, if desired. In some arrangements, user input for controlling system  8  can include both user finger input and other user input (e.g., user eye gaze input, user voice input, etc.). For example, gaze tracking information such as a user&#39;s point-of-gaze measured with a gaze tracker can be fused with finger input when controlling device  10  and/or devices  24  in system  8 . A user may, for example, gaze at an object of interest while device  10  using one or more of sensors  18  (e.g., an accelerometer, force sensor, touch sensor, etc.) to gather information such as tap input (movement of device  10  resulting in measurable forces and/or accelerometer output when device  10  strikes a table top or other external surface), double-tap input, force input, multi-finger gestures (taps, swipes, and/or other gestures on external surfaces and/or the housing surfaces of multiple devices  10 ), drag and drop operations associated with objects selected using a lingering gaze or other point-of-gaze input, etc. The finger input may include information on finger orientation, position, and/or motion and may include information on how forcefully a finger is pressing against surfaces (e.g., force information). Finger pointing input (e.g., the direction of finger pointing) may be gathered using radio-frequency sensors among sensors  18  and/or other sensors in device(s)  10 . 
     If desired, user input may include air gestures (sometimes referred to as three-dimensional gestures or non-contact gestures) gathered with sensors  18  (e.g., proximity sensors, image sensors, ultrasonic sensors, radio-frequency sensors, etc.). Air gestures (e.g., non-contact gestures in which a user&#39;s fingers hover and/or move relative to the sensors  18  of device  10  and/or in which device  10  hovers and/or moves relative to external surfaces) and/or touch and/or force-based input may include multifinger gestures (e.g., pinch to zoom, etc.). In some embodiments, a user may wear multiple devices  10  (e.g., on a thumb and index finger) and these devices may be used to gather finger pinch input such as pinch click gesture input or pinch force input. For example, a pinch click input may be detected when a tap (e.g., a peak in an accelerometer output signal) for a thumb device correlates with a tap for an index finger device and/or pinch force input may be gathered by measuring strain gauge output with strain gauges in devices  10  as the devices  10  press against each other. Pinch force can also be detected by measuring the size of the contact patch produced when a finger presses against a two-dimensional touch sensor (larger contact area being associated with larger applied force). As another example, pinch input and/or other finger gestures that involve contact with the finger pad may be detected using a proximity sensor that measures small changes in distance to the finger as the finger pad is moved (e.g., as the finger pad of a pointer finger is moved around by a thumb finger and/or moved around by a surface as the finger pad makes contact with the surface). 
     By correlating user input from a first of devices  10  with user input from a second of devices  10  and/or by otherwise analyzing finger device sensor input, pinch gestures (e.g., pinch click or pinch tap gestures and/or pinch force input) and other multi-device input may be detected and used in manipulating virtual objects or taking other actions in system  8 . Consider, as an example, the use of a pinch gesture to select a virtual object associated with a user&#39;s current point-of-gaze. Once the virtual object has been selected based on the direction of the user&#39;s point-of-gaze (or finger point direction input) and based on the pinch gesture input or other user input, further user input gathered with one or more devices  10  may be used to rotate and/or otherwise manipulate the virtual object. For example, information on finger movement (e.g., rotational movement) may be gathered using an internal measurement unit or other sensor  18  in device(s)  10  and this rotational input used to rotate the selected object. In some scenarios, an object may be selected based on point-of-gaze (e.g., when a user&#39;s point-of-gaze is detected as being directed toward the object) and, following selection, object attributes (e.g., virtual object attributes such as virtual object appearance and/or real-world object attributes such as the operating settings of a real-world device) can be adjusted using strain gauge or touch sensor contact patch pinch input (e.g., detected pinch force between finger devices  10  that are being pinched together on opposing fingers) and/or can be adjusted using finger device orientation input (e.g., to rotate a virtual object, etc.). 
     If desired, gestures such as air gestures (three-dimensional gestures) may involve additional input. For example, a user may control system  8  using hybrid gestures that involve movement of device(s)  10  through the air (e.g., an air gesture component) and that also involve contact (and, if desired, movement) of a thumb or other finger against a two-dimensional touch sensor, force sensor, or other sensor  18 . As an example, an inertial measurement unit may detect user movement of finger  40  through the air (e.g., to trace out a path) while detecting force input, touch input, or other input (e.g., finger pinch input or other input to adjust a line or other virtual object that is being drawn along the path). 
     The sensors in device  10  may, for example, measure how forcefully a user is moving device  10  (and finger  40 ) against surface  48  (e.g., in a direction parallel to the surface normal n of surface  48  such as the −Z direction of  FIG.  3   ) and/or how forcefully a user is moving device  10  (and finger  40 ) within the X-Y plane, tangential to surface  48 . The direction of movement of device  10  in the X-Y plane and/or in the Z direction can also be measured by the force sensors and/or other sensors  18  at locations  46 . 
     Structure  50  may be a portion of a housing of device  24 , may be a portion of another device  10  (e.g., another housing  44 ), may be a portion of a user&#39;s finger  40  or other body part, may be a surface of a real-world object such as a table, a movable real-world object such as a bottle or pen, or other inanimate object external to device  10 , and/or may be any other structure that the user can contact with finger  40  while moving finger  40  in a desired direction with a desired force. Because motions such as these can be sensed by device  10 , device(s)  10  can be used to gather pointing input (e.g., input moving a cursor or other virtual object on a display such as a display in devices  36 ), can be used to gather tap input, swipe input, pinch-to-zoom input (e.g., when a pair of devices  10  is used), or other gesture input (e.g., finger gestures, hand gestures, arm motions, etc.), and/or can be used to gather other user input. 
       FIG.  4    is a top view of an illustrative finger device on a finger of a user. In the illustrative configuration of  FIG.  4   , device  10  includes one or more proximity sensors such as proximity sensors  52 . Proximity sensors  52  (sometimes referred to as distance sensors or displacement sensors) may each be configured to measure a distance D between finger  40  and proximity sensor  52 . The distances between finger  40  and sensors  52  may change as the user moves finger  40  in the air, touches finger  40  on a surface, and/or touches finger  40  with another finger. Based on the distance changes recorded by each sensor  52 , control circuitry  12  may determine how finger  40  is moving and may take corresponding action. For example, control circuitry  12  may send control signals to one or more electronic devices (e.g., device  24  of  FIG.  1   ) in response to the finger movements measured by sensors  52 . 
     Proximity sensors in device  10  such as sensors  52  may be optical sensors (e.g., having a light source and a light detector), ultrasonic sensors (e.g., having a ultrasonic transducer and a corresponding detector), magnetic sensors, capacitive sensors, pressure sensors, and/or other sensors configured to gather information on the distance D between finger  40  and sensors  52 . Arrangements in which sensors  52  are based on piezoelectric materials or based on mechanical switches may also be used, if desired. 
     In one illustrative arrangement, which may sometimes be described herein as an example, proximity sensors  52  (sometimes referred to as distance sensors or displacement sensors) may include self-mixing interferometric proximity sensors (sometimes referred to as self-mixing optical proximity sensors, self-mixing proximity sensors, self-mixing interferometers, etc.). A self-mixing proximity sensor may have a coherent or partially coherent source of electromagnetic radiation. The source of radiation may, for example, be a coherent light source such as an infrared vertical cavity surface-emitting laser, a quantum cascade laser, or other laser. The self-mixing proximity sensor may also have a light detector such as a photodiode and/or other electromagnetic-radiation-sensitive element. 
     Self-mixing proximity sensors may have submicron resolution and may be configured to detect very small changes in distance. This allows sensors  52  to detect very small movements of finger  40  (sometimes referred to as microgestures or nanogestures). If desired, the optical axis of each sensor  52  may be angled towards a center region of the finger pad to increase sensor sensitivity to finger displacements that result from the finger pad contacting an external surface or another finger. 
       FIGS.  5 ,  6 ,  7 ,  8 ,  9 ,  10 ,  11 ,  12 ,  13 , and  14    show illustrative examples of user input that may be detected with proximity sensors  52  in device  10  such as self-mixing optical proximity sensors. 
     In the example of  FIG.  5   , finger device  10  is being used to detect finger input to the finger pulp. In particular, one or more proximity sensors  52  in device  10  may measure changes in distance between sensors  52  and finger  40 - 1  (e.g., a pointer finger or other suitable finger wearing device  10 ) as finger  40 - 2  (e.g., a thumb or other suitable finger) makes contact with finger pulp  40 P of finger  40 - 1 . Sensors  52  may detect lateral movement of finger pulp  40  in which pulp  40 P moves relative to finger  40 - 2  and may also detect movement of finger pulp  40 P with little or no actual movement of pulp  40 P relative to finger  40 - 2 . For example, the user may use finger  40 - 2  to move finger pulp  40 P around (e.g., from side-to-side, from front-to back, from back-to-front, or any other suitable direction) without actually sliding finger  40 - 2  across finger pulp  40 P. Because this movement of finger pulp  40 P somewhat resembles the movement of a joystick, this type of input may sometimes be referred to as joystick input. Sensors  52  may also detect taps and pinches between fingers  40 - 1  and  40 - 2 , since such movements will push the sides of finger  40 - 1  outward towards sensors  52  and will therefore result in corresponding changes in distance between the sides of finger  40 - 1  and sensors  52 . 
       FIG.  6    shows an example in which finger device  10  is being used to detect finger input on a surface of structure  50 . In particular, one or more proximity sensors  52  in device  10  may measure changes in distance between sensors  52  and finger  40  (e.g., a pointer finger or other suitable finger wearing device  10 ) as finger  40  makes contact with structure  50 . Sensors  52  may detect lateral movement of finger pulp  40 P in which pulp  40 P moves relative to structure  50  and may also detect movement of finger pulp  40 P with little or no actual movement of pulp  40 P relative to structure  50 . For example, the user may move finger pulp  40 P around on structure  50  (e.g., from side-to-side, from front-to back, from back-to-front, or any other suitable direction) without actually sliding finger  40  across structure  50 . Because this movement of finger pulp  40 P somewhat resembles the movement of a joystick, this type of input may sometimes be referred to as joystick input. Sensors  52  may also detect taps and presses of finger  40  on structure  50 , since such movements will push the sides of finger  40 - 1  outward towards sensors  52  and will therefore result in corresponding changes in distance between the sides of finger  40 - 1  and sensors  52 . 
       FIGS.  7 ,  8 , and  9    show illustrative movements of finger pulp  40 P that may be detected using distance sensors such as proximity sensors  52 . For simplicity, device  10  is not shown in these figures, but it should be understood that device  10  may be mounted on top of finger  40  and may have one or more proximity sensors such as sensors  52  that measure distance changes between finger  40  and sensors  52  as finger pulp  40 P moves around (e.g., as finger pulp  40 P is moved around by another finger such as a user&#39;s thumb as shown in  FIG.  5    and/or as finger pulp  40 P is moved around by a surface as shown in  FIG.  6   ). 
     In the example of  FIG.  7   , finger pulp  40 P of finger  40  is being moved to the left in direction  60 . This movement may be a result of the user moving finger  40  (and/or applying shear force) on a surface to the right in direction  54 , or this may be a result of a user pushing finger pulp  40 P to the left in direction  60  with another finger (e.g., a thumb finger or other suitable finger). The movement of finger pulp  40 P in direction  60  results in distance change D 1  on the right side of finger  40  and distance change D 2  on the left side of finger  40 . D 1  represents the distance traveled by the right side portion of finger  40  as finger  40  moves in direction  60 , and D 2  represents the distance traveled by the left side portion of finger  40  as finger  40  moves in direction  60 . 
     In the example of  FIG.  8   , finger pulp  40 P of finger  40  is being moved diagonally in direction  62 . This movement may be a result of the user moving finger  40  (and/or applying shear force) on a surface in direction  56 , or this may be a result of a user pushing finger pulp  40 P in direction  62  with another finger (e.g., a thumb finger or other suitable finger). The movement of finger pulp  40 P in direction  62  results in distance change D 3  on the end of finger  40  and distance change D 4  on the right side of finger  40 . D 3  represents the distance traveled by the end (e.g., the tip) of finger  40  as finger  40  moves in direction  62 , and D 4  represents the distance traveled by the right side of finger  40  as finger  40  moves in direction  62 . 
     In the example of  FIG.  9   , finger pulp  40 P of finger  40  is being moved forward in direction  64 . This movement may be a result of the user moving finger  40  (and/or applying shear force) on a surface in direction  58 , or this may be a result of a user pushing finger pulp  40 P in direction  64  with another finger (e.g., a thumb finger or other suitable finger). The movement of finger pulp  40 P in direction  64  results in distance change D 5  on the end of finger  40 . D 5  represents the distance traveled by the end (e.g., the tip) of finger  40  as finger  40  moves in direction  64 . 
     The examples of  FIGS.  7 ,  8 , and  9    are merely illustrative examples of the types of finger movements that may be detected using one or more proximity sensors  52  in device  10 . Proximity sensors  52  may be configured to detect taps, presses, pinches, and/or other suitable finger gestures by measuring the small changes in distance between finger  40  and sensor(s)  52  that result from such finger gestures. Sensors  52  may include any suitable number of sensors at any suitable location on device  10  (e.g., one or more sensors  52  may be located on the right side of finger  40 , may be located on the left side of finger  40 , may be located on the tip of finger  40 , may be located on top of the fingernail of finger  40 , and/or may be located in other positions relative to finger  40 ). If desired, displacement data from multiple sensors  52  may be compared to determine precisely the amount and direction with which finger  40  (e.g., finger pulp  40 P) moves in response to finger gestures made with the finger wearing device  10 . 
     In addition to detecting movement of finger pulp  40 P, sensors  52  may be used to detect other finger gestures that result in changes in distance between finger  40  and sensors  52 .  FIGS.  10 ,  11 ,  12 ,  13 , and  14    are illustrative examples of other types of finger gestures that may be detected using proximity sensors  52  (e.g., optical proximity sensors such as self-mixing optical proximity sensors and/or other proximity sensors that can measure changes in the position of finger  40 ). 
       FIG.  10    is an example in which device  10  is being used to detect the proximity of one or more adjacent fingers. In particular, device  10  may be worn on finger  40 - 1  (e.g., a pointer finger or other suitable finger) and may detect activities of finger  40 - 2  (e.g., a middle finger or other suitable finger) as it makes contact with and/or as it comes in proximity to device  10 . For example, sensor  52  may detect a decrease in distance between sensor  52  and finger  40 - 1  as finger  40 - 2  makes contact with finger  40 - 1  (and/or makes contact with device  10  on finger  40 - 1 ). Detecting when finger  40 - 2  is in contact with or close proximity to finger  40 - 1  may be used to provide a different type of input than that associated with a single finger. For example, finger gestures made with two side-by-side fingers as shown in  FIG.  10    may be used to scroll content on a display whereas finger gestures made with a single finger may be used to move a cursor on a display, if desired. 
       FIG.  11    shows an example in which finger device  10  is being used to detect finger input on device  10 . In particular, device  10  may be worn on finger  40 - 1  (e.g., a pointer finger or other suitable finger) and may detect activities of finger  40 - 2  (e.g., a thumb or other suitable finger) as it makes contact with and/or as it comes in proximity to device  10 . For example, proximity sensor  52  may measure a change in distance between sensor  52  and finger  40 - 1  as finger  40 - 2  contacts the exterior surface of device  10 . In this way, sensors  52  can detect swipes, pinches, taps, presses, press-and-holds, or other gestures on device  10 . 
       FIG.  12    shows an example in which finger device  10  is being used to detect finger input on top of device  10 . In particular, device  10  may be worn on finger  40 - 1  (e.g., a pointer finger or other suitable finger) and may detect activities of finger  40 - 2  (e.g., a middle finger or other suitable finger) as it makes contact with the upper surface of device  10 . For example, proximity sensor  52  may measure a change in distance between sensor  52  and finger  40 - 1  as finger  40 - 2  contacts the upper surface of device  10 . Sensor  52  may measure changes in the position of the top of finger  40 - 1  relative to sensor  52  (e.g., changes in the position of the fingernail relative to sensor  52 ) and/or may measure changes in position of one or more sides of finger  40 - 1  relative to sensor  52  as finger  40 - 2  contacts the top of finger  40 - 1  (and/or the top of device  10 ). In this way, sensors  52  can detect finger gestures on the upper surface of device  10 . 
       FIG.  13    is an example showing how device  10  may be used to turn an object into an input device. In the example of  FIG.  13   , object  68  may be a pen or pencil that does not contain any circuitry. A user wearing one or more finger devices  10  may rotate object  68  about its longitudinal axis, may move the tip of object  68  across a surface (e.g., surface  48  of structure  50  of  FIG.  3   ), and/or may tap or press the tip of object  68  on a surface, and/or may make other movements of object  68 . During movement of object  68 , proximity sensors  52  in device  10  may detect small changes in distance between finger  40  and sensors  52 , which in turn can be used to determine the location, orientation, and movement of object  68 . 
       FIG.  14    shows an example in which finger device  10  is being used to detect a curling motion of finger  40 . In particular, device  10  may be worn on finger  40  (e.g., a pointer finger or other suitable finger) and may detect movement of the tip of finger  40  relative to the base of finger  40 . As the tip of finger  40  curls in direction  72 , the sides of finger  40  may be pushed outward, resulting in small changes in distance between proximity sensors  52  and finger  40 . By measuring these small changes in distance with sensor(s)  52 , device  10  can measure the position of the tip of finger  40  as it moves relative to the base of finger  40 . 
     If desired, the finger gestures of  FIGS.  5 - 14    may be combined with one another and/or combined with other finger gestures to provide different types of user input to an electronic device. As an example, a user may select an item on a display in device  24  by tapping finger  40  on a surface (as shown in the example of  FIG.  6   ) and, once the item has been selected, the user may manipulate the selected item by moving finger pulp  40 P with a thumb like one would move a joystick (e.g., as shown in  FIG.  5   ). Multi-finger gestures may be detected by detecting an adjacent finger as the user pinches against the finger pulp of a finger wearing device  10 , by detecting an adjacent finger as the user presses a finger wearing device  10  against a surface, by detecting an adjacent finger as the user touches the outside of device  10 , etc. 
       FIG.  15    is a diagram of an illustrative self-mixing proximity sensor (sometimes referred to as a self-mixing sensor or proximity sensor) and an associated target. As shown in  FIG.  15   , self-mixing proximity sensor  52  may include a laser such as vertical cavity surface emitting laser  74  (e.g., self-mixing proximity sensor  52  may be a coherent self-mixing sensor having a diode laser or other coherent or partially coherent source of light or other electromagnetic radiation). Laser  74  may have thin-film interference filter mirrors  90  (sometimes referred to as Bragg reflectors) each of which is formed from a stack of thin-film layers of alternating index of refraction. Active region  94  may be formed between mirrors  90 . The lower mirror in laser  74  may have a nominal reflectivity of 100% or, in configurations such as bottom-emitting configurations, may have a nominal reflectivity of less than 100%. In some cases, the laser can emit from both the top and bottom. This is particularly useful if the laser is sitting above a photodetector. The upper mirror in laser  74  may have a slightly lower reflectivity, so that laser  74  emits light  86  towards target  82 . Laser  74  may be controlled by applying a drive signal to terminals  92  using control circuitry  12  (e.g., a drive circuit in circuitry  12 ). Sensing circuitry in circuitry  12  can measure the light output of laser  74 . 
     Emitted light  86  may have a wavelength of 850 nm or other suitable wavelength (e.g., a visible wavelength, an ultraviolet wavelength, an infrared wavelength, a near-infrared wavelength, etc.). Target  82  may be, for example, part of the user&#39;s finger (e.g., the side portions of the user&#39;s finger near the fingernail) and/or may be a flexible membrane in device  10  that rests against the user&#39;s finger and that moves in response to movement of the finger. When emitted light  86  illuminates target  82 , some of emitted light  86  will be reflected backwards towards proximity sensor  52 . Proximity sensor  52  may include a light sensitive element (e.g., a light detector) such as photodiode  76  (e.g., a resonant cavity photodetector or other suitable light detector). Terminals  96  of photodiode  76  may be coupled to sensing circuitry in control circuitry  12 . This circuitry gathers photodiode output signals that are produced in response to reception of reflected light  88 . In addition to using a photodiode, self-mixing can be detected using laser junction voltage measurements (e.g., if the laser is driven at a constant bias current) or laser bias current (e.g., if the laser is driven at a constant voltage). A protective cover such as protective structure  80  may, if desired, be mounted over laser  74  and photodiode  76 . Protective structure  80  may be transparent (or may have transparent portions). If desired, a lens element such as lens element  102  may be incorporated into or attached to structure  80  to help direct light to target  82  and increase the signal-to-noise ratio of proximity sensor  52 . 
     Target  82  is located at a distance P 1  from proximity sensor  52 . Proximity sensor  52  may have a height P 2  and a width P 3 . Height P 2  may be between 0.5 mm and 1 mm, between 1 mm and 2 mm, between 0.1 mm and 0.5 mm, between 1 mm and 5 mm, less than 3 mm, greater than 3 mm, or other suitable height. Width P 3  may be between 0.5 mm and 1 mm, between 1 mm and 2 mm, between 0.1 mm and 0.5 mm, between 1 mm and 5 mm, less than 2 mm, greater than 2 mm, or other suitable width. 
     Some of light  88  that is reflected or backscattered from target  82  reenters the laser cavity of laser  74  and perturbs the electric field coherently, which also reflects as a perturbation to the carrier density in laser  74 . These perturbations in laser  74  causes coherent self-mixing fluctuations in the power of emitted light  86  and associated operating characteristics of laser  74  such as laser junction voltage and/or laser bias current. These fluctuations may be monitored. For example, the fluctuations in the power of light  86  may be monitored using photodiode  76 . In the example of  FIG.  15   , photodiode  74  and laser  76  are formed adjacent to each other on the upper surface of substrate  78 . 
     As shown in  FIG.  16   , control circuitry  12  includes circuitry for implementing a driver for laser  74  (drive circuit  12 - 1 ) and circuitry for implementing a sensing circuit for photodiode  76  (sense circuit  12 - 2 ). Drive circuit  12 - 1  is used in applying a modulated drive current Id to laser  74 . Sense circuit  12 - 2  is used in gathering signals PDout from photodiode  76  that are processed by control circuitry  12  or output signals may be gathered using junction voltage or bias current measurements. 
     A modulation scheme is used for driving laser  74  for the purpose of inducing a wavelength modulation, and a photodiode signal processing scheme or junction voltage or bias current processing scheme is used in processing the measured self-mixing fluctuations in output power to that allow control circuitry  12  to determine the distance P 1  between proximity sensor  52  and target  82  in accordance with the principles of self-mixing interferometry. 
     A modulation scheme for driving laser  74  may, for example, use a sinusoidal wave drive signal, a triangular wave drive signal, and/or other suitable drive signal that, due to the dependence of output wavelength on drive current magnitude of laser  74 , continuously varies the wavelength of light  86 . The wavelength variations of light  86  cause the self-mixing interference signal of laser  74  to exhibit ripples. The processing scheme used on the photodiode signal can extract information from these ripples, from which distance P 1  may be calculated. Distance P 1  may, for example, be determined within less than 1 micron accuracy, less than 0.2 mm accuracy, less than 0.15 mm accuracy, less than 0.1 mm accuracy, less than 0.01 mm accuracy, or other suitable accuracy. Due to this high accuracy, measurements of extremely small changes in the position of finger  40  can be made with a high confidence. 
     The example of  FIG.  15    in which laser  74  and photodiode  76  are formed side-by-side on substrate  78  is merely illustrative. Other arrangements may be used, if desired. For example, photodiode  76  may be formed or bonded under laser  74 , may be monolithically integrated into laser  74 , or may be formed or bonded on top of laser  74 . In the example of  FIG.  17   , photodiode  76  is an integrated monolithic photodiode that is formed under laser  74 . If desired, photodiode  76  may be an intra-cavity photodiode that is located in the cavity of laser  74  (e.g., between reflectors  92  of  FIG.  15   ). 
     In the example of  FIG.  18   , photodiode  76  is an integrated monolithic photodiode having a ring-shape that surrounds laser  74 . Laser  74  may have a corresponding ring-shaped portion  74 - 1  that surrounds an inner portion  74 - 2 . If desired, inner portion  74 - 2  may be forward biased and outer ring-shaped portion  74 - 1  may be reverse biased. Inner portion  74 - 2  may emit light  86 . If desired, a beam splitter such as beam splitter  98  may be placed between portion  74 - 2  of laser  74  and target  82 . 
     In the example of  FIG.  19   , laser  74  has been coupled to a separate photodiode  76  using coupling structures  100  (e.g., solder bumps, epoxy, adhesive, etc.). If desired, laser  74  may emit light  86  from the top and bottom of laser  74 . The top-emitted light  86  may be directed to target  82  and the bottom emitted light may be absorbed by photodiode  76 . 
       FIG.  20    is a cross-sectional side view of an illustrative finger device with proximity sensors  52 . As shown in  FIG.  20   , optical proximity sensors may be separated from target  82  by cavity  116 . Cavity  116  may be filled with air, fluid, and/or other suitable material through which optical signals associated with proximity sensor  52  may pass as light passes from sensor  52  to target  82  and from target  82  to sensor  52 . In the example of  FIG.  20   , target  82  is a flexible membrane (e.g., a flexible layer of silicone, polymer, or other material) that rests against the sides of finger  40 . As finger  40  moves, the distance between membrane  82  and sensor  52  (e.g., distance P 1  of  FIG.  15   ) may change. These changes in distance between membrane  82  and sensor  52  may be measured to thereby detect movements of different portions of finger  40  (e.g., micromovements associated with the finger gestures described in connection with  FIGS.  3 - 14   ). 
     The use of optical proximity sensors for sensors  52  is merely illustrative. Proximity sensors in device  10  such as sensors  52  may be ultrasonic sensors (e.g., having a ultrasonic transducer and a corresponding detector), magnetic sensors, capacitive sensors, pressure sensors, and/or other sensors configured to gather information on the location and movement of finger  40 . 
     If desired, proximity sensor  52  may include a pressure sensor (e.g., in addition to or instead of an optical distance sensor) in cavity  116  that measures barometric pressure changes as membrane  82  moves in response to finger movement. Arrangements in which membrane  82  incorporates one or more force sensors may also be used. For example, membrane  82  may include a strain gauge for measuring force and/or may include a capacitive electrode that is used to measure force (e.g., by detecting a change in distance between the electrode on membrane  82  and an electrode in sensor  52 ). 
       FIGS.  21 ,  22 ,  23 ,  24 , and  25    show illustrative locations and numbers of proximity sensors  52  in device  10 . In the example of  FIG.  21   , a single proximity sensor  52  is located on the left side of finger  40 , and a single proximity sensor  52  is located on the right side of finger  40 . If desired, the sensors may not be directly opposite one another (e.g., one sensor  52  may be closer to the tip of finger  40  than the other sensor  52  so that data from the two sensors  52  can be compared to detect front-to-back movements as well as side-to-side movements). 
     In the example of  FIG.  22   , two sensors  52  are located only on one side of device  10 . The data from the two sensors  52  may be compared to detect front-to-back movements as well as side-to-side movements. 
     In the example of  FIG.  23   , two sensors  52  are located on the left side of device  10 , and one sensor  52  is located on the right side of device  10 . The data from sensors  52  may be compared to detect front-to-back movements as well as side-to-side movements. 
       FIGS.  24  and  25    show illustrative examples in which device  10  includes sensors  52  on the sides and the tip of the user&#39;s finger. In the example of  FIG.  24   , device  10  does not cover the user&#39;s fingernail. In the  FIG.  25    example, the fingernail is covered by device  10 . The examples of  FIGS.  21 - 25    are merely illustrative. There may be one, two, three, four, five, six, ten, more than ten, or less than ten sensors  52  in device  10  mounted in any suitable location of device  10 . 
       FIGS.  26 ,  27 ,  28 ,  29 ,  30 , and  31    are diagrams of device  10  showing illustrative locations of sensors  52 . As shown in  FIG.  26   , device  10  may include first and second housing portions  108  coupled by hinge  104 . Hinge  104  may allow housing portions  108  to be moved towards or away from each other to accommodate fingers of different sizes. Each housing portion  108  may have a sidewall portion such as sidewall portion  106  that extends down a side portion of the user&#39;s finger. In the example of  FIG.  26   , proximity sensors  52  are located on opposing sides of sidewall portion  106 .  FIG.  27    shows an example in which proximity sensors  52  are located on sidewall portion  106  itself. 
       FIG.  28    shows an example in which sensors  52  are located in an upper portion of device  10  (e.g., in housing portions  108 ) so that sensors  52  rest on the user&#39;s fingernail  42 . 
     In the example of  FIG.  29   , device  10  has a thimble shape with an opening  114  for receiving the user&#39;s finger. The user may insert his or her finger in opening  114  in direction  112 . Device  10  may have an additional opening such as opening  110  that exposes the finger pad of the finger. Since device  10  has a finger glove shape that covers most of the tip of the user&#39;s finger, sensors  52  may be located below the user&#39;s finger (adjacent to the finger pad which is exposed through opening  110 ), on the sides of the user&#39;s finger, on top of the user&#39;s finger, at the tip of the user&#39;s finger, and/or in any other suitable location of device  10 . 
       FIG.  30    shows an example in which sidewall portion  106  extends down a back end of the tip of finger  40  (e.g., closer to the joint between the distal phalanx and the middle phalanx). This provides additional real estate along the side portions of the fingertip for sensors  52 . In particular, sensors  52  may be mounted in side housing portion  106 P. Side housing portion  106 P may be formed from the same or different material as side housing portion  106 . If desired, side housing portion  106 P may be formed from a softer and/or more flexible material than side housing portion  106 . For example, side housing portion  106  may be rigid to provide the desired clamping force to hold device  10  on finger  40 , while side housing portion  106 P may be flexible so that finger movements will cause corresponding deformations in housing  106 P (e.g., in membrane  82  in housing  106 P) that can be detected by sensors  52 . 
     Sensors  52  may be located at the same height of the side portion of the user&#39;s finger  40 , as shown in  FIG.  30   . In another suitable arrangement, sensors  52  may be located at different heights along the side portion of the user&#39;s finger  40 . This type of arrangement is illustrated in  FIG.  31   . As shown in  FIG.  31   , sensors  52  may be offset with respect to one another (e.g., offset from one another such that one sensor  52  is closer to top housing portion  108  than the other sensor  52 ). For example, sensor  52  that is closer to the tip of finger  40  may be higher and closer to top housing portion  108  than the other sensor  52  that is closer to the back end of the fingertip. This type of arrangement may help ensure that front sensors  52  do not inadvertently strike the surface that finger  40  is contacting while wearing device  10 . If desired, control circuitry  14  may process sensor data to compensate for any decreased sensitivity in sensors  52  that results from being higher up on the side of the finger. 
     It may be desirable to incorporate biasing structures in device  10  to keep device  10  appropriately positioned on finger  40 . For example, when side housing portion  106  is closer to the back end of the fingertip, as in the examples of  FIGS.  30  and  31   , biasing structure  120  may be used to bias top housing portion  108  towards finger  40 . Biasing structure  120  (e.g., a spring) may help minimize rotation of housing  108  away from finger  40  about pivot point  118 . 
       FIG.  32    is a side view of device  10  showing how side housing portion  106  may have a curved portion such as curved portion  106 C. Curved portion  106 C may be curved away from the middle phalanx to minimize bulging of finger  40  at location  124 , which might otherwise cause device  10  to become misplaced on finger  40 . 
       FIG.  33    is a cross-sectional side view of device  10  showing how a strap may be used to help secure device  10  to finger  40 . Strap  40  may have a first end coupled to a first of side portions  106  and a second end coupled to a second of side portions  106 . Strap  40  may be elastic (e.g., may be formed from an elastomeric polymer), may be formed from fabric, and/or may be formed from other materials. Strap  40  may be permanently attached to side housing portions  106  or may be removable (e.g., may be coupled to portions  106  with an attachment structure such as a buckle, snap, tie, magnets, etc.). Strap  40  may extend around a bottom portion of finger  40  closer to the middle phalanx of finger  40  so that the finger pad of finger  40  can contact external surfaces without interference by strap  40 . 
     As described above, one aspect of the present technology is the gathering and use of information such as sensor information. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, eyeglasses prescription, username, password, biometric information, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to deliver targeted content that is of greater interest to the user. Accordingly, use of such personal information data enables users to have control of the delivered content. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the United States, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA), whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another example, users can select not to provide certain types of user data. In yet another example, users can select to limit the length of time user-specific data is maintained. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an application (“app”) that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data at a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20200915
Publication Date: 20230912
Grant Date: 20230912
Priority Date: 20190923
Inventors: CIHAN, AHMET FATIH
Dey, Stephen E.
HARB, ADRIAN Z.
HUANG, MENGSHU
PAN, Yuhao
WANG, PAUL X.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/014", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2203/0331", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/962", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/968", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K2217/96062", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/014", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/0331", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/014", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/0331", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 87933341