# US 10,484,656 B1 · Driver system resonant frequency determination > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,656 B1 - Document ID: US10484656B1 - Status: Granted - Kind: B1 - Application number: 16/217,609 - Filed: 2018-12-12 - Granted: 2019-11-19 - Earliest claimed: 2018-12-12 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Microsoft Technology Licensing, LLC - Inventors: Chuan Pu; Wenjun Liao - Web page: https://patentgrep.com/patent/US10484656B1 ## CPC - H04N 9/3194: {including sensor feedback} - G02B 26/101: {with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129)} - G02B 27/0172: {characterised by optical features} - G06F 3/038: Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry - G09G 3/346: {based on modulation of the reflection angle, e.g. micromirrors (micromirrors devices per se G02B26/0833)} - G09G 5/00: Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators (image data processing or generation, in general G06T) - H04N 9/3135: {Driving therefor} - G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD - G09G 2330/12: Test circuits or failure detection circuits included in a display system, as permanent part thereof - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A display device is provided, including a laser beam emitter, a fast-scan driver system including a nonlinear driver and a fast-scan MEMS sensor, and a slow-scan MEMS driver. The nonlinear driver and the slow-scan MEMS driver may respectively drive a fast-scan mirror and a slow-scan mirror. The display device may further include a signal generator configured to generate a periodic electrical signal. The nonlinear driver may receive, amplify, and drive the fast-scan mirror with the amplified electrical signal. The fast-scan MEMS sensor may detect a motion of the fast-scan mirror. The display device may further include a signal detector configured to receive and detect an amplitude difference between a periodic electrical signal and a fast-scan MEMS sensor output signal. The display device may further include a processor configured to receive the amplitude difference and determine a driver system resonant frequency of the fast-scan driver system. ## Claims ### Claim 1 A display device comprising: a laser beam emitter configured to emit a laser beam; a fast-scan driver system including a nonlinear driver and a fast-scan microelectromechanical (MEMS) sensor; a slow-scan MEMS driver, wherein: the nonlinear driver and the slow-scan MEMS driver are respectively configured to drive a fast-scan mirror and a slow-scan mirror; and the slow-scan mirror and the fast-scan mirror are configured to reflect the laser beam onto a display region; a signal generator configured to generate a periodic electrical signal having a first frequency in response to receiving periodic electrical signal instructions, wherein the nonlinear driver is configured to: receive the periodic electrical signal from the signal generator; amplify the periodic electrical signal to produce an amplified signal; and drive the fast-scan mirror with the amplified electrical signal, wherein the fast-scan MEMS sensor is configured to detect a motion of the fast-scan mirror; a signal detector configured to: receive the periodic electrical signal from the signal generator and a fast-scan MEMS sensor output signal from the fast-scan MEMS sensor; and detect an amplitude difference between the periodic electrical signal and the fast-scan MEMS sensor output signal; and a processor configured to: receive the amplitude difference from the signal detector; and determine, based on the amplitude difference, a driver system resonant frequency of the fast-scan driver system. ### Claim 2 (depends on 1) The display device of claim 1, wherein the processor is configured to determine the driver system resonant frequency at least in part by determining a phase difference between the periodic electrical signal and the fast-scan MEMS sensor output signal. ### Claim 3 (depends on 1) The display device of claim 1, wherein: the processor is further configured to: generate modified periodic electrical signal instructions based on the driver system resonant frequency; and transmit the modified periodic electrical signal instructions to the signal generator; and in response to receiving the modified periodic electrical signal instructions, the signal generator is configured to generate a modified periodic electrical signal with a second frequency different from the first frequency. ### Claim 4 (depends on 3) The display device of claim 3, wherein the second frequency is the driver system resonant frequency. ### Claim 5 (depends on 3) The display device of claim 3, wherein the processor is configured to determine the driver system resonant frequency at least in part by detecting a plurality of amplitude differences in a respective plurality of fast-scan periods that occur during the non-display interval. ### Claim 6 (depends on 5) The display device of claim 5, wherein the processor is configured to generate the modified periodic electrical signal instructions at least in part by iteratively updating the first frequency over the plurality of fast-scan periods. ### Claim 7 (depends on 3) The display device of claim 3, wherein the signal generator includes a phase-locked loop. ### Claim 8 (depends on 7) The display device of claim 7, wherein the processor is configured to generate the modified periodic electrical signal instructions at least in part by modifying a lock angle of the phase-locked loop to have a target lock angle. ### Claim 9 (depends on 7) The display device of claim 7, wherein the processor is configured to determine the driver system resonant frequency at least in part by determining a gain of the signal generator when the fast-scan driver system receives the periodic electrical signal from the signal generator. ### Claim 10 (depends on 1) The display device of claim 1, wherein, during the non-display interval, the slow-scan mirror returns from a final scanning position to an initial scanning position. ### Claim 11 A method for use with a display device, the method comprising: scanning a display region with a slow-scan mirror driven by a slow-scan microelectromechanical systems (MEMS) driver; and in a fast-scan period of a fast-scan mirror driven by a nonlinear driver: at a signal generator, generating a periodic electrical signal, the periodic electrical signal having a first frequency; transmitting the periodic electrical signal to a signal detector and a nonlinear driver; amplifying the periodic electrical signal at the nonlinear driver to produce an amplified signal; driving the fast-scan mirror with the amplified electrical signal; at the signal detector: receiving the periodic electrical signal and a fast-scan MEMS sensor output signal; detecting an amplitude difference between the periodic electrical signal and the fast-scan MEMS sensor output signal; and transmitting the amplitude difference to a processor; and at the processor, determining, based on the amplitude difference, a driver system resonant frequency of a fast-scan driver system including the nonlinear driver. ### Claim 12 (depends on 11) The method of claim 11, wherein determining the driver system resonant frequency includes determining a phase difference between the periodic electrical signal and the MEMS sensor output signal. ### Claim 13 (depends on 11) The method of claim 11, further comprising generating, based on the driver system resonant frequency, a modified periodic electrical signal with a second frequency different from the first frequency. ### Claim 14 (depends on 13) The method of claim 13, wherein the second frequency is the driver system resonant frequency. ### Claim 15 (depends on 13) The method of claim 13, wherein determining the driver system resonant frequency includes detecting a plurality of amplitude differences in a respective plurality of fast-scan periods that occur during the non-display interval. ### Claim 16 (depends on 15) The method of claim 15, wherein generating the modified periodic electrical signal includes iteratively updating the first frequency over the plurality of fast-scan periods. ### Claim 17 (depends on 13) The method of claim 13, wherein: the signal generator includes a phase-locked loop; and generating the modified periodic electrical signal includes modifying a lock angle of the phase-locked loop to have a target lock angle. ### Claim 18 (depends on 17) The method of claim 17, wherein determining the driver system resonant frequency includes determining a gain of the signal generator when the fast-scan driver system receives the periodic electrical signal from the signal generator. ### Claim 19 (depends on 11) The method of claim 11, wherein scanning the display region includes reflecting a laser beam off the slow-scan mirror and the fast-scan mirror onto the display region. ### Claim 20 A display device comprising: a laser beam emitter configured to emit a laser beam; a fast-scan driver system including a nonlinear driver and a fast-scan MEMS sensor; a slow-scan MEMS driver, wherein: the nonlinear driver and the slow-scan MEMS driver are respectively configured to drive a fast-scan mirror and a slow-scan mirror; and the slow-scan mirror and the fast-scan mirror are configured to reflect the laser beam onto a display region; a signal generator that includes a phase-locked loop and is configured to generate a periodic electrical signal having a first frequency, wherein the nonlinear driver is configured to: receive the periodic electrical signal from the signal generator; amplify the periodic electrical signal to produce an amplified signal; and drive the fast-scan mirror with the amplified electrical signal, wherein the fast-scan MEMS sensor is configured to detect a motion of the fast-scan mirror; a signal detector configured to: receive the periodic electrical signal from the signal generator and a fast-scan MEMS sensor output signal from the fast-scan MEMS sensor; detect an amplitude difference between the periodic electrical signal and the fast-scan MEMS sensor output signal; and a processor configured to: receive the amplitude difference from the signal detector; and determine, based on the amplitude difference, a gain of the signal generator; and generate, based on the gain, a modified periodic electrical signal with a second frequency different from the first frequency.