# US 2022/0035150 A1 · Drive circuit for resonant mirror scanning system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0035150 A1 - Document ID: US20220035150A1 - Status: Published application - Kind: A1 - Application number: 16/945,349 - Filed: 2020-07-31 - Published: 2022-02-03 - Earliest claimed: 2020-07-31 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Microsoft Technology Licensing, LLC - Inventors: Chang Joon PARK; Martin Francis GALINSKI, III - Web page: https://patentgrep.com/patent/US20220035150A1 ## CPC - G02B 26/085: {the reflecting means being moved or deformed by electromagnetic means} - G02B 26/0858: {the reflecting means being moved or deformed by piezoelectric means} - 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)} - G02B 26/10: Scanning systems - G02B 27/0176: {characterised by mechanical features} - H03H 7/1708: {Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path (H03H7/07 takes precedence)} - H03H 7/175: {Series LC in series path (H03H7/1783 takes precedence)} - G02B 2027/0154: {with movable elements} - H03H 2007/006: {MEMS} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract Examples are disclosed herein that relate to driving a resonant scanning mirror system using a linear LC resonant driving scheme. In one example, a resonant scanning mirror system includes a scanning mirror, first and second mirror drive elements, and a drive circuit to drive the scanning mirror at a resonant frequency. The drive circuit includes one or more signal sources configured to create a first source signal and a second source signal that is 180 degrees out of phase with the first source signal. The drive circuit further includes a buffer stage configured to receive the first and second source signals and output first and second drive signals, a first resonant LC stage configured to amplify the first drive signal for provision to the first mirror drive element, and a second resonant LC stage configured to amplify the second drive signal for provision to the second mirror drive element. ## Claims ### Claim 1 A display device, comprising: a resonant scanning mirror system comprising a scanning mirror, a first mirror drive element, and a second mirror drive element; and a drive circuit configured to drive the scanning mirror at a resonant frequency, the drive circuit comprising one or more signal sources configured to create a first source signal and a second source signal, the first source signal being 180 degrees out of phase with the second source signal; a buffer stage configured to receive the first source signal and the second source signal and to output a first drive signal and a second drive signal; a first resonant LC stage configured to amplify the first drive signal for provision to the first mirror drive element; and a second resonant LC stage configured to amplify the second drive signal for provision to the second mirror drive element. ### Claim 2 (depends on 1) The display device of claim 1, wherein the buffer stage comprises an operational amplifier stage. ### Claim 3 (depends on 2) The display device of claim 2, wherein the operational amplifier stage comprises a unity gain stage. ### Claim 4 (depends on 1) The display device of claim 1, wherein the first resonant LC stage comprises a first winding of a coupled inductor, and wherein the second resonant LC stage comprises a second winding of the coupled inductor. ### Claim 5 (depends on 1) The display device of claim 1, wherein the first resonant LC stage utilizes a first parasitic capacitance of the scanning mirror system, and wherein the second resonant LC stage utilizes a second parasitic capacitance of the scanning mirror system. ### Claim 6 (depends on 5) The display device of claim 5, wherein the first resonant LC stage further comprises a first tuning capacitor. ### Claim 7 (depends on 1) The display device of claim 1, wherein the first mirror drive element comprises a first piezoelectric drive element, and wherein the second mirror drive element comprises a second piezoelectric drive element. ### Claim 8 (depends on 1) The display device of claim 1, wherein the display device comprises a head-mounted display. ### Claim 9 A display device, comprising: a resonant scanning mirror system comprising a scanning mirror, a first mirror drive element, and a second mirror drive element; and a drive circuit configured to drive the scanning mirror at a resonant frequency, the drive circuit comprising one or more signal sources configured to create a first source signal and a second source signal, the first source signal being 180 degrees out of phase with the second source signal; a buffer stage configured to receive the first source signal and the second source signal and to output a first drive signal and a second drive signal respectively based upon the first source signal and the second source signal; a first resonant LC stage configured to amplify the first drive signal for provision to the first mirror drive element, the first resonant LC stage comprising a first winding of a coupled inductor; and a second resonant LC stage configured to amplify the second drive signal for provision to the second mirror drive element, the second resonant LC stage comprising a second winding of a coupled inductor. ### Claim 10 (depends on 9) The display device of claim 9, wherein the operational amplifier stage comprises a unity gain stage. ### Claim 11 (depends on 9) The display device of claim 9, wherein the first resonant LC stage utilizes a first parasitic capacitance of the scanning mirror system, and wherein the second resonant LC stage utilizes a second parasitic capacitance of the scanning mirror system. ### Claim 12 (depends on 11) The display device of claim 11, wherein the first resonant LC stage further comprises a first tuning capacitor. ### Claim 13 (depends on 9) The display device of claim 9, wherein the first mirror drive element comprises a first piezoelectric drive element, and wherein the second mirror drive element comprises a second piezoelectric drive element. ### Claim 14 (depends on 9) The display device of claim 9, wherein the display device comprises a head-mounted display. ### Claim 15 A method of operating a scanning mirror system of a display device, comprising: generating a first source signal and a second source signal, the first source signal and the second source signal being 180 degrees out of phase; inputting the first source signal and the second source signal into a buffer stage and outputting a first drive signal and a second drive signal from the buffer stage; amplifying the first drive signal at a resonant frequency of a resonant mirror via a first resonant LC stage; amplifying the second drive signal at the resonant frequency of the resonant mirror via a second resonant LC stage; providing the first drive signal to a first mirror drive element; and providing the second drive signal to a second mirror drive element. ### Claim 16 (depends on 15) The method of claim 15, wherein inputting the first source signal and the second source signal into a buffer stage comprises inputting the first source signal and the second source signal into a unity gain stage. ### Claim 17 (depends on 15) The method of claim 15, wherein amplifying the first drive signal at the resonant frequency of the resonant mirror via the first resonant LC stage comprises utilizing a first winding of a coupled inductor, and wherein amplifying the second drive signal at the resonant frequency of the resonant mirror via a second resonant LC stage comprises utilizing a second winding of the coupled inductor. ### Claim 18 (depends on 15) The method of claim 15, wherein amplifying the first drive signal at the resonant frequency of the resonant mirror via the first resonant LC stage comprises utilizing a first parasitic capacitance of the scanning mirror system, and wherein amplifying the second drive signal at the resonant frequency of the resonant mirror via a second resonant LC stage comprises utilizing a second parasitic capacitance of the scanning mirror system inductor. ### Claim 19 (depends on 15) The method of claim 15, wherein amplifying the first drive signal at the resonant frequency of the resonant mirror via the first resonant LC stage further comprises utilizing a first tuning capacitor. ### Claim 20 (depends on 15) The method of claim 15, wherein the display device comprises a head-mounted display.