# US 11,115,574 B2 · Control circuit of liquid lens, camera module and method of controlling liquid lens > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,574 B2 - Document ID: US11115574B2 - Status: Granted - Kind: B2 - Application number: 16/816,989 - Filed: 2020-03-12 - Published: 2020-07-02 - Granted: 2021-09-07 - Earliest claimed: 2017-04-11 - Assignees: LG Innotek Co., Ltd. - Applicants: LG Innotek Co., Ltd. - Inventors: Young Seop Moon; Young Woon Kim - Web page: https://patentgrep.com/patent/US11115574B2 ## CPC - H04N 23/55: Optical parts specially adapted for electronic image sensors; Mounting thereof - G01R 27/2605: {Measuring capacitance (capacitive sensors G01D5/24)} - G02B 26/005: {based on electrowetting} - G02F 1/29: for the control of the position or the direction of light beams, i.e. deflection - G03B 13/36: Autofocus systems - 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)} - G02B 2207/115: Electrowetting - G02F 1/294: {Variable focal length devices} - G02F 2201/121: common or background - G03B 5/00: Adjustment of optical system relative to image or object surface other than for focusing - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) ## Abstract Disclosed is a liquid lens control circuit, which includes a liquid lens including a plurality of individual electrodes disposed in compartmental areas at the same level and a common electrode disposed at a different level from that of the individual electrodes, a voltage control circuit configured to supply voltages to the common electrode and at least one of the individual electrodes in the liquid lens in order to control an interface in the liquid lens, and a capacitance measuring circuit configured to calculate a capacitance between the common electrode and at least one of the individual electrodes in the liquid lens using a switched capacitor. ## Claims ### Claim 1 A camera module, comprising: a holder comprising a first side wall, the first side wall having a first hole formed therethrough; a focus adjustable lens disposed in the first hole and comprising a common electrode and a plurality of individual electrodes; a voltage control circuit configured to supply a driving voltage to the focus adjustable lens in order to control an interface in the focus adjustable lens, the voltage control circuit configured to supply the driving voltage based on a capacitance between the common electrode and at least one individual electrode of the plurality of individual electrodes in the focus adjustable lens; a capacitance measuring circuit configured to measure the capacitance between the common electrode and the at least one individual electrode of the plurality of individual electrodes in the focus adjustable lens; and a first switch located between the capacitance measuring circuit and the focus adjustable lens, wherein one side of the first switch is electrically connected to the focus adjustable lens and the voltage control circuit. ### Claim 2 (depends on 1) The camera module according to claim 1, wherein the capacitance measuring circuit is configured to measure the capacitance between the common electrode and each individual electrode of the plurality of individual electrodes. ### Claim 3 (depends on 1) The camera module according to claim 1, comprising a second switch located between the voltage control circuit and the first switch and between the voltage control circuit and the focus adjustable lens, wherein the one side of the first switch is electrically connected to the voltage control circuit via the second switch. ### Claim 4 (depends on 3) The camera module according to claim 3, wherein the second switch is turned on when a common electrode voltage is supplied to the common electrode, and turned off when the capacitance measuring circuit measures the capacitance. ### Claim 5 (depends on 1) The camera module according to claim 1, wherein, when the common electrode is floating after a ground voltage is supplied to the common electrode after a shape of the interface is changed by the driving voltage, the capacitance is measured during a period when the first switch is turned on and a voltage supplied to the at least one individual electrode is changed from a first voltage to a second voltage having a lower level than the first voltage. ### Claim 6 (depends on 1) The camera module according to claim 1, wherein the first switch is turned off when the voltage control circuit supplies the driving voltage to the focus adjustable lens for operating the focus adjustable lens. ### Claim 7 (depends on 1) The camera module according to claim 1, wherein the voltage control circuit comprises: a first voltage control circuit configured to supply a common electrode voltage to the common electrode; and a second voltage control circuit configured to supply individual electrode voltages to the plurality of individual electrodes, respectively, the driving voltage being created via interaction between the common electrode voltage and at least one individual electrode voltage of the individual electrode voltages. ### Claim 8 (depends on 7) The camera module according to claim 7, wherein the common electrode voltage and the at least one individual electrode voltage are applied to the common electrode and the individual electrode at different times, respectively. ### Claim 9 (depends on 1) The camera module according to claim 1, wherein the voltage control circuit is configured to generate the driving voltage used for operating the focus adjustable lens as well as to accumulate electric charge used for measuring the capacitance between the common electrode and the at least one individual electrode. ### Claim 10 (depends on 1) The camera module according to claim 1, wherein the capacitance measuring circuit includes a reference capacitor, and wherein the capacitance between the common electrode and the at least one individual electrode is measured by using the reference capacitor. ### Claim 11 (depends on 1) The camera module according to claim 1, wherein the holder comprises a second side wall opposite the first sidewall in a first direction perpendicular to an optical axis of the camera module, and wherein the second side wall has a second hole formed therethrough. ### Claim 12 (depends on 1) The camera module according to claim 1, wherein the holder comprises a first plate having a cavity in which the focus adjustable lens is disposed. ### Claim 13 A camera module, comprising: a holder comprising a first side wall, the first side wall having a first hole formed therethrough; a focus adjustable lens including a common electrode, a first feedback electrode, a plurality of individual electrodes, and a second feedback electrode; a voltage control circuit configured to supply a driving voltage to the focus adjustable lens in order to control an interface in the focus adjustable lens, the voltage control circuit configured to supply the driving voltage based on a capacitance between the first feedback electrode and the second feedback electrode in the focus adjustable lens; and a feedback voltage control circuit transferring a feedback voltage to any one of the first feedback electrode and the second feedback electrode, in order to measure the capacitance between the first feedback electrode and the second feedback electrode, wherein the second feedback electrode is disposed between the individual electrodes, and wherein the first feedback electrode is disposed at a position corresponding to the second feedback electrode. ### Claim 14 (depends on 13) The camera module according to claim 13, comprising a capacitance measuring circuit configured to measure the capacitance between the first feedback electrode and the second feedback electrode in the focus adjustable lens. ### Claim 15 (depends on 13) The camera module according to claim 13, wherein the holder comprises: a second side wall opposite the first sidewall in a first direction perpendicular to an optical axis of the camera module; and a first plate having a cavity in which the focus adjustable lens is disposed, and wherein the second side wall has a second hole formed therethrough. ### Claim 16 A camera module, comprising: a holder comprising a first side wall, the first side wall having a first hole formed therethrough; a focus adjustable lens disposed in the holder and comprising a common electrode and a plurality of individual electrodes; a voltage control circuit configured to supply a driving voltage to the focus adjustable lens in order to control an interface in the focus adjustable lens, the voltage control circuit configured to supply the driving voltage based on a capacitance between the common electrode and at least one individual electrode of the plurality of individual electrodes in the focus adjustable lens; a capacitance measuring circuit configured to measure the capacitance between the common electrode and the at least one individual electrode of the plurality of individual electrodes in the focus adjustable lens; a first switch located between the capacitance measuring circuit and the focus adjustable lens; and a second switch located between the voltage control circuit and the first switch and between the voltage control circuit and the focus adjustable lens, wherein the capacitance measuring circuit is configured to measure the capacitance between the common electrode and each individual electrode of the plurality of individual electrodes, wherein one side of the first switch is electrically connected to the focus adjustable lens and the voltage control circuit, wherein the second switch is turned on when a common electrode voltage is supplied to the common electrode, and turned off when the capacitance measuring circuit measures the capacitance, wherein, when the common electrode is floating after a ground voltage is supplied to the common electrode after a shape of the interface is changed by the driving voltage, the capacitance is measured during a period when the first switch is turned on and a voltage supplied to the at least one individual electrode is changed from a first voltage to a second voltage having a lower level than the first voltage, wherein the first switch is turned off when the voltage control circuit supplies the driving voltage to the focus adjustable lens for operating the focus adjustable lens, wherein the voltage control circuit comprises: a first voltage control circuit configured to supply a common electrode voltage to the common electrode; and a second voltage control circuit configured to supply individual electrode voltages to the plurality of individual electrodes, respectively, the driving voltage being created via interaction between the common electrode voltage and at least one individual electrode voltage of the individual electrode voltages, wherein the common electrode voltage and the at least one individual electrode voltage are applied to the common electrode and the individual electrode at different times, respectively, wherein the voltage control circuit is configured to generate the driving voltage used for operating the focus adjustable lens as well as to accumulate electric charge used for measuring the capacitance between the common electrode and the at least one individual electrode, wherein the capacitance measuring circuit includes a reference capacitor, wherein the capacitance between the common electrode and the at least one individual electrode is measured by using the reference capacitor, wherein the holder comprises: a second side wall opposite the first sidewall in a first direction perpendicular to an optical axis of the camera module; and a first plate having a cavity in which the focus adjustable lens is disposed, and wherein the second side wall has a second hole formed therethrough.