# US 10,484,583 B2 · Inductive three-axis lens position measurement using AF and OIS coils > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,583 B2 - Document ID: US10484583B2 - Status: Granted - Kind: B2 - Application number: 15/236,176 - Filed: 2016-08-12 - Published: 2017-04-27 - Granted: 2019-11-19 - Earliest claimed: 2015-10-22 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Thomas M. Gregory; Albert A. Ho; Richard J. Topliss; Richard H. Tsai - Web page: https://patentgrep.com/patent/US10484583B2 ## CPC - G02B 7/09: adapted for automatic focusing or varying magnification - G02B 7/08: adapted to co-operate with a remote control mechanism - G02B 7/28: Systems for automatic generation of focusing signals - G02B 27/646: {compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68)} - H04N 23/57: Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices - H04N 23/6812: {based on additional sensors, e.g. acceleration sensors} - H04N 23/687: {by shifting the lens or sensor position} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Some embodiments include a camera of a mobile computing device. In some embodiments, the camera includes an autofocus coil for moving a lens module, a plurality of optical image stabilization coils, a driver circuit element, connected to the autofocus coil, for passing an alternating current waveform through the autofocus coil, and one or more measurement circuit elements, connected to respective ones of the plurality of the optical image stabilization coils, for measuring changes induced in currents in the respective ones of the plurality of the optical image stabilization coils by the waveform. ## Claims ### Claim 1 A camera of a mobile computing device, comprising: a lens module; an image sensor; an autofocus coil and one or more optical image stabilization coils configured to generate relative motion between the image sensor and the lens module, wherein the autofocus coil is mechanically connected to one or more of the lens module and the image sensor, and each of the one or more optical image stabilization coils is mechanically connected to one or more of the lens module and the image sensor; one or more driver circuit elements, connected to the autofocus coil, configured to pass a current through the autofocus coil; and one or more measurement circuit elements connected to respective ones of the one or more optical image stabilization coils, the one or more measurement circuit elements configured to measure changes induced in currents in the respective ones of the one or more optical image stabilization coils to enable determination of a position of the autofocus coil. ### Claim 2 (depends on 1) The camera of claim 1, wherein the one or more driver circuit elements comprise an AC driver circuit element, connected to the autofocus coil, for passing an alternating current waveform through the autofocus coil; and the one or more measurement circuits comprise one or more AC measurement circuit elements, connected to respective ones of the one or more optical image stabilization coils, for measuring changes induced in currents in the respective ones of the one or more optical image stabilization coils by the alternating current waveform. ### Claim 3 (depends on 1) The camera of claim 1, wherein the autofocus coil comprises a coil for generating force to compel relative motion between the image sensor and the lens module along an optical axis between the image sensor and a lens of the lens module; and the one or more optical image stabilization coils comprise one or more of optical image stabilization coils for generating force to compel relative motion between the image sensor and the lens module along one or more directions orthogonal to the optical axis between the image sensor and a lens of the lens module. ### Claim 4 (depends on 1) The camera of claim 1, wherein the one or more measurement circuit elements further comprise: one or more voltage measurement elements for measuring voltage differences created by the changes induced in the currents in the respective ones of the one or more optical image stabilization coils by an alternating current waveform. ### Claim 5 (depends on 1) The camera of claim 1, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis. ### Claim 6 (depends on 1) The camera of claim 1, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis; and the camera excludes dedicated magnetic field sensors for detecting motion of the autofocus coil. ### Claim 7 (depends on 1) The camera of claim 1, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis; and the camera excludes dedicated capacitance sensors for detecting motion of the autofocus coil. ### Claim 8 (depends on 1) The camera of claim 1, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis; and the camera excludes dedicated optical range finder sensors for detecting motion of the autofocus coil. ### Claim 9 A method for measuring a position of an autofocus coil, comprising: delivering an alternating electrical signal to the autofocus coil that is distinct from one or more optical image stabilization coils; and calculating a position of the autofocus coil by measuring a voltage associated with a current induced in one or more of the optical image stabilization coils by the alternating current delivered to the autofocus coil. ### Claim 10 (depends on 9) The method of claim 9, wherein calculating a position of the autofocus coil further comprises: generating closed loop feedback measurement of a position of a lens module associated with the autofocus coil with respect to three or more axes. ### Claim 11 (depends on 9) The method of claim 9, wherein the measuring the voltage associated with the current induced in the one or more optical image stabilization coils by the alternating current further comprises: measuring the voltage when an image sensor associated with the autofocus coil is not performing an exposure to reduce image capture noise associated with the image sensor being active. ### Claim 12 (depends on 9) The method of claim 9, wherein the delivering the alternating electrical signal to the autofocus coil further comprises: delivering a zero-mean current waveform applied in superposition to the existing drive current of an actuator used to move a lens module of a digital camera; and measuring the voltage associated with the current induced in the one or more optical image stabilization coils by the alternating current. ### Claim 13 (depends on 9) The method of claim 9, wherein the delivering the alternating electrical signal to the autofocus coil further comprises: delivering the alternating electrical signal to the autofocus coil through a PWM type AF coil drive scheme. ### Claim 14 (depends on 9) The method of claim 9, wherein the delivering the alternating electrical signal to the autofocus coil further comprises: adjusting a position of a lens module using a closed-loop feedback based upon the measuring. ### Claim 15 A camera actuator, comprising: an autofocus coil for moving a lens module; a plurality of optical image stabilization coils that are distinct from the autofocus coil; a driver circuit element, connected to the autofocus coil, for passing an alternating current waveform through the autofocus coil; and one or more measurement circuit elements, connected to respective ones of the plurality of the optical image stabilization coils, for measuring changes induced in currents in the respective ones of the plurality of the optical image stabilization coils by the waveform passing through the autofocus coil. ### Claim 16 (depends on 15) The camera actuator of claim 15, wherein the one or more measurement circuit elements further comprise: one or more voltage measurement elements for measuring voltage differences created by the changes induced in the currents in the respective ones of the plurality of the optical image stabilization coils by the waveform. ### Claim 17 (depends on 15) The camera actuator of claim 15, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis. ### Claim 18 (depends on 15) The camera actuator of claim 15, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis; and the camera excludes dedicated magnetic field sensors for detecting motion of the autofocus coil. ### Claim 19 (depends on 15) The camera actuator of claim 15, wherein the one or more measurement circuit elements further comprise measurement elements capable of detecting components of motion of the autofocus coil in at least a direction of an optical axis of the lens module and at least two directions perpendicular to the optical axis; and the camera excludes dedicated capacitance sensors for detecting motion of the autofocus coil. ### Claim 20 (depends on 15) The camera actuator of claim 15, wherein the autofocus coil comprises a coil for generating force to compel relative motion between the lens module and an image sensor along an optical axis between a lens of the lens module and the image sensor; and the plurality of optical image stabilization coils comprise coils for generating force to compel relative motion between the lens module and the image sensor along one or more directions orthogonal to the optical axis between the lens of the lens module and the image sensor.