# US 2014/0360272 A1 · Capacitive transducer drive device and object information acquiring device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360272 A1 - Document ID: US20140360272A1 - Status: Published application - Kind: A1 - Application number: 14/290,463 - Filed: 2014-05-29 - Published: 2014-12-11 - Earliest claimed: 2013-06-07 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Atsushi Kandori - Web page: https://patentgrep.com/patent/US20140360272A1 ## CPC - H02N 1/006: {of the gap-closing type (H02N1/004 takes precedence)} - B06B 1/0207: {Driving circuits (specially adapted for particular applications, see the relevant subclass, e.g. G01; circuits for steering transducer arrays G10K11/34; basic circuits H03)} - B06B 1/0292: {Electrostatic transducers, e.g. electret-type} - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R) ## Abstract Provided is a capacitive transducer drive device capable of adjusting a potential difference applied between electrodes of a cell with a simple configuration. A capacitive transducer to be driven by the drive device includes a cell including: a first electrode included in a vibrating membrane; and a second electrode formed to oppose the first electrode through intermediation of a gap. One of the first electrode and the second electrode of the cell is electrically connected to a first DC voltage applying unit, and the other of the first electrode and the second electrode of the cell is electrically connected to a second DC voltage applying unit. A voltage to be applied by the second DC voltage applying unit is set to be lower than a voltage to be applied by the first DC voltage applying unit. The voltage to be applied by the second DC voltage applying unit is variable. ## Claims ### Claim 1 A drive device for a capacitive transducer, the capacitive transducer comprising a cell, the cell comprising a vibrating membrane, a first electrode included in the vibrating membrane, and a second electrode formed to oppose the first electrode through intermediation of a gap, the drive device comprising: a first DC voltage applying unit electrically connected to one of the first electrode and the second electrode included in the cell; and a second DC voltage applying unit electrically connected to another of the first electrode and the second electrode included in the cell, wherein the second DC voltage applying unit is configured to apply, to the another of the first electrode and the second electrode, a voltage lower than a voltage applied to the one of the first electrode and the second electrode by the first DC voltage applying unit, and wherein the voltage applied by the second DC voltage applying unit is variable. ### Claim 2 (depends on 1) The drive device for a capacitive transducer according to claim 1, which is configured to execute at least one of a function of transmitting an acoustic wave by vibrating the vibrating membrane in response to a transmission voltage signal or a function of receiving an acoustic wave in response to a reception current signal obtained when the first electrode vibrates in response to the acoustic wave. ### Claim 3 (depends on 1) The drive device for a capacitive transducer according to claim 1, further comprising a transceiver circuit comprising at least one of a transmission voltage generation unit or a reception current detection unit, wherein the transceiver circuit is connected for each element, the element being a group of at least one cell in which the second electrode of the at least one cell is electrically connected, and wherein the second DC voltage applying unit is connected to the second electrode via the transceiver circuit. ### Claim 4 (depends on 3) The drive device for a capacitive transducer according to claim 3, wherein the second DC voltage applying unit is connected to the second electrode via wiring included in the transceiver circuit, and wherein the transmission voltage generation unit is connected to the wiring via an AC coupling unit, and the reception current detection unit is connected to the wiring via another AC coupling unit. ### Claim 5 (depends on 3) The drive device for a capacitive transducer according to claim 3, wherein the transmission voltage generation unit comprises the second DC voltage applying unit. ### Claim 6 (depends on 3) The drive device for a capacitive transducer according to claim 3, wherein the reception current detection unit comprises the second DC voltage applying unit. ### Claim 7 (depends on 3) The drive device for a capacitive transducer according to claim 3, which is configured to vary a DC voltage to be applied by the second DC voltage applying unit to adjust a potential difference between the first electrode and the second electrode so that the potential difference is close to characteristics of at least one of transmission efficiency or reception sensitivity of the element. ### Claim 8 (depends on 3) The drive device for a capacitive transducer according to claim 3, wherein the capacitive transducer comprises a plurality of the elements, and wherein the second DC voltage applying unit is configured to apply a DC voltage that is different for each different element having the same shape of the cells. ### Claim 9 (depends on 3) The drive device for a capacitive transducer according to claim 3, which is configured to set, in a plurality of the elements that perform transmission operation substantially at the same time, voltages to be applied by the second DC voltage applying unit to the plurality of the elements to have different values between peripheral elements and central elements of the plurality of the elements. ### Claim 10 (depends on 1) An object information acquiring device, comprising: the drive device for a capacitive transducer according to claim 1; and a processor configured to acquire information on an object by using an electric signal output from the capacitive transducer, wherein the capacitive transducer is configured to receive an acoustic wave from the object and output the electric signal. ### Claim 11 (depends on 1) An object information acquiring device, comprising: the drive device for a capacitive transducer according to claim 1; a light source; and a data processing device, wherein the capacitive transducer is configured to receive an acoustic wave generated by light that is oscillated from the light source to irradiate an object, and convert the received acoustic wave into an electric signal, and wherein the data processing device is configured to acquire information on the object by using the electric signal. ### Claim 12 A method of driving a capacitive transducer, the capacitive transducer comprising a cell, the cell comprising a vibrating membrane, a first electrode included in the vibrating membrane, and a second electrode formed to oppose the first electrode through intermediation of a gap, the method comprising: setting a voltage applied to another of the first electrode and the second electrode included in the cell to be lower than a voltage applied to one of the first electrode and the second electrode included in the cell; and varying the voltage applied to the another of the first electrode and the second electrode.