# US 12,114,130 B2 · Microelectromechanical sound transducer system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,114,130 B2 - Document ID: US12114130B2 - Status: Granted - Kind: B2 - Application number: 17/887,242 - Filed: 2022-08-12 - Published: 2023-03-30 - Granted: 2024-10-08 - Earliest claimed: 2022-08-12 - Assignees: Robert Bosch GmbH - Applicants: Arioso Systems GmbH - Inventors: Lutz Ehrig; Tilman Koch - Web page: https://patentgrep.com/patent/US12114130B2 ## CPC - H04R 3/06: of electrostatic transducers - H04R 19/02: Loudspeakers (H04R19/01 takes precedence) - G10K 11/178: by electro-acoustically regenerating the original acoustic waves in anti-phase - H04R 1/1075: {Mountings of transducers in earphones or headphones} - H04R 19/005: {using semiconductor materials} - H04R 19/04: Microphones (H04R19/01 takes precedence) - H04R 17/00: Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) - H04R 25/604: {of acoustic or vibrational transducers} - H04R 29/001: {for loudspeakers (H04R29/007 takes precedence)} - H04R 2201/003: Mems transducers or their use - H04R 2460/01: Hearing devices using active noise cancellation - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR ## Abstract This invention relates to a microelectromechanical loudspeaker implemented as a system-on-chip or system-in-package. The microelectromechanical loudspeaker includes a microelectromechanical sound-generating device implemented in a microelectromechanical system (MEMS) and a microphone mounted on the cover or integrated in the cover, wherein the microphone is positioned adjacent to one of the sound outlet openings of the cover. The MEMS comprises a cavity formed between a planar cover, a planar base and circumferential sidewalls provided between the cover and the base. The MEMS further comprises a plurality of movable actuators for generating sound. The actuators are provided in the cavity between the cover and the base, and wherein the cover and the base have a plurality of sound outlet openings to emit sound in a direction transverse to the cover and the base, respectively. ## Claims ### Claim 1 A microelectromechanical loudspeaker system implemented as a system-on-chip or system-in-package, comprising: a microelectromechanical sound-generating device implemented in a microelectromechanical system (MEMS), wherein the MEMS comprises a cavity formed between a planar cover, a planar base and circumferential sidewalls provided between the cover and the base, wherein the MEMS further comprises a plurality of movable actuators for generating sound, wherein the actuators are provided in the cavity between the cover and the base, and wherein the cover comprises a plurality of sound outlet openings to emit sound in a direction transverse to the cover; a microphone mounted on the cover or integrated in the cover, wherein the microphone is positioned adjacent to at least one sound outlet opening of the cover. ### Claim 2 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the acoustic path between the microphone and the at least one adjacent sound outlet opening is less than or equal to 2 mm. ### Claim 3 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the microelectromechanical loudspeaker system implements an active noise cancelling (ANC) function, wherein the microphone is configured to detect the sound emitted through the sound outlet openings of the cover and interference noise; and the microelectromechanical loudspeaker system further comprises a control system configured to control the sound generation of the microelectromechanical sound-generating device based on the sound detected by the microphone and interference noise such that the detected interference noise is suppressed; wherein the control system is configured to control sound generation of the microelectromechanical sound-generating device using an actuation signal that drives the actuators, and to receive a feedback signal from the microphone, wherein the feedback signal represents the sound emitted through the sound outlet openings of the cover and the interference noise. ### Claim 4 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the position of the microphone on the cover is selected such that the phase difference between the actuation signal and the feedback signal is less than or equal to 2° to realize a cut-off frequency of at least 1 kHz. ### Claim 5 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the microelectromechanical sound-generating device is a multilayer silicon device; wherein the cover, the base, and the actuators are formed in different layers of the multilayer silicon device. ### Claim 6 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the microphone is a discrete MEMS-based component mounted on the cover of the microelectromechanical sound-generating device. ### Claim 7 (depends on 6) The microelectromechanical loudspeaker system according to claim 6, wherein the microphone is connected to the cover of the microelectromechanical sound-generating device in an electrically conductive manner to supply a feedback signal to the control system via electrically conductive paths of the microelectromechanical sound-generating device, wherein the feedback signal represents the sound emitted through the sound outlet openings of the cover and the interference noise. ### Claim 8 (depends on 5) The microelectromechanical loudspeaker system according to claim 5, wherein the microphone is formed in one or more semiconductor layers of the semiconductor device on a side of the cover facing away from the actuators. ### Claim 9 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the control system is arranged on the base and/or the cover of the microelectromechanical sound-generating device and is connected to the microelectromechanical sound-generating device in an electrically conductive manner. ### Claim 10 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the microelectromechanical loudspeaker system comprises a plurality of microphones positioned in the planar footprint of the microelectromechanical sound-generating device between respective adjacent sound outlet openings of the cover, wherein the microphones are configured to detect the sound emitted through the respective sound outlet openings of the cover and any interference noise; wherein the acoustic path between each of the microphones and one of its adjacent sound outlet openings is less than or equal to 2 mm. ### Claim 11 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the cavity of the microelectromechanical sound-generating device consists of multiple independent sub-cavities, wherein each of the independent sub-cavities comprises one or more of the actuators for generating sound in an associated frequency band of the audible frequency spectrum which is emitted through sound outlet openings of the cover and the base provided in the planar footprint of each of the sub-cavities; wherein the microelectromechanical loudspeaker system comprises multiple microphones provided on the cover or integrated in the cover of the microelectromechanical sound-generating device to detect the sound generated and emitted from each of the independent sub-cavities and interference noise. ### Claim 12 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the actuators are movable in a plane that is parallel to the cover and/or transverse to the direction of the sound emitted from the cover. ### Claim 13 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the cover has a stiffness selected to avoid structure-borne sound coupling between the cover and the microphone mounted on the cover or integrated in the cover. ### Claim 14 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the cover has a stiffness configured so that a sound pressure component caused by a vibration of the cover is at least 60 dB lower than the sound pressure component caused by the sound emitted through the sound outlet openings of the cover. ### Claim 15 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the microphone comprises a membrane to receive sound emitted through the sound outlet openings of the cover and interference noise, wherein the membrane is excited in a direction substantially perpendicular to a plane defined by the planar surface of the planar cover. ### Claim 16 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the actuators are movable in a plane that is transverse to the direction of sound transmission of the microelectromechanical sound-generating device; wherein the plurality of sound outlet openings to emit sound in the direction of sound transmission which is transverse to the cover (201). ### Claim 17 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the actuators are driven electrostatically. ### Claim 18 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the cover has a stiffness selected to avoid structure-borne sound coupling between the cover and the microphone mounted on the cover or integrated in the cover. ### Claim 19 (depends on 1) The microelectromechanical loudspeaker system according to claim 1, wherein the cover has a stiffness configured so that a sound pressure component caused by a vibration of the cover is at least 60 dB lower than the sound pressure component caused by the sound emitted through the sound outlet openings of the cover. ### Claim 20 (depends on 1) A device with a microelectromechanical loudspeaker system according to claim 1, wherein the device is designed as a near-field speaker, a headphone, or as a hearing aid.