# US 2021/0344302 A1 · Flexible lissajous scanning pattern by phase modulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344302 A1 - Document ID: US20210344302A1 - Status: Published application - Kind: A1 - Application number: 16/861,647 - Filed: 2020-04-29 - Published: 2021-11-04 - Earliest claimed: 2020-04-29 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: David BRUNNER; Georg SCHITTER; Richard SCHROEDTER; Han Woong YOO - Web page: https://patentgrep.com/patent/US20210344302A1 ## CPC - H03B 5/30: with frequency-determining element being electromechanical resonator - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) ## Abstract An oscillator system includes a first oscillator structure configured to oscillate about a first rotation axis at a first oscillation frequency; a second oscillator structure configured to oscillate about a second rotation axis at a second oscillation frequency; a driver circuit configured to generate a first driving signal to drive an oscillation of the first oscillator structure with a first oscillation phase and the first oscillation frequency and generate a second driving signal to drive an oscillation of the second oscillator structure with a second oscillation phase and the second oscillation frequency. The first oscillation frequency and the second oscillation frequency have a variable frequency ratio with respect to each other that varies over time. The driver circuit is configured to modulate at least one of the first oscillation phase or the second oscillation phase to modulate the variable frequency ratio. ## Claims ### Claim 1 An oscillator system, comprising: a first oscillator structure configured to oscillate about a first rotation axis at a first oscillation frequency; a second oscillator structure configured to oscillate about a second rotation axis at a second oscillation frequency; and a driver circuit configured to generate a first driving signal to drive an oscillation of the first oscillator structure with a first oscillation phase and the first oscillation frequency, and generate a second driving signal to drive an oscillation of the second oscillator structure with a second oscillation phase and the second oscillation frequency, wherein the first oscillation frequency and the second oscillation frequency have a variable frequency ratio with respect to each other that varies over time, wherein the driver circuit is configured to modulate at least one of the first oscillation phase or the second oscillation phase to modulate the variable frequency ratio. ### Claim 2 (depends on 1) The oscillator system of claim 1, wherein the driver circuit comprises a master control circuitry configured to generate the first driving signal and generate at least one synchronization signal, and a slave control circuitry configured to generate the second driving signal based on the at least one synchronization signal. ### Claim 3 (depends on 2) The oscillator system of claim 2, wherein the at least one synchronization signal includes a frame synchronization signal configured to synchronize a start of a frame period for both the first oscillator structure and the second oscillator structure. ### Claim 4 (depends on 2) The oscillator system of claim 2, wherein the at least one synchronization signal includes a phase synchronization signal configured to synchronize a rotation angle of the oscillation of the second oscillator structure with expected zero-crossing times. ### Claim 5 (depends on 4) The oscillator system of claim 4, wherein: the master control circuit is configured to receive a constant phase shift parameter and generate the phase synchronization signal based on the constant phase shift parameter. ### Claim 6 (depends on 5) The oscillator system of claim 5, wherein the slave control circuitry is configured to continuously phase shift the expected zero-crossing times of the second oscillator structure with respect to expected zero-crossing times of the first oscillator structure over a frame period based on the phase synchronization signal. ### Claim 7 (depends on 5) The oscillator system of claim 5, wherein the slave control circuitry is configured to constantly change a phase shift of the oscillation of the second oscillator structure with respect to the oscillation of the first oscillator structure based on the phase synchronization signal. ### Claim 8 (depends on 4) The oscillator system of claim 4, wherein: the slave control circuitry comprises a phase detector, wherein the phase detector is configured to receive the phase synchronization signal, a phase error corresponding to an error in zero-crossing times of the oscillation of the second oscillator structure, and a phase modulation signal indicating a phase modulation, and generate a modulated phase error signal based thereon, wherein the slave control circuitry is configured to modulate a duty cycle of the second driving signal based on the modulated phase error signal. ### Claim 9 (depends on 8) The oscillator system of claim 8, wherein the phase detector is configured to measure an actual phase difference between the first oscillation phase and the second oscillation phase, calculate a system phase error between the actual phase difference and an expected phase difference between the first oscillation phase and the second oscillation phase, and add the phase modulation signal to the system phase error to generate the modulated phase error signal ### Claim 10 (depends on 1) The oscillator system of claim 1, wherein the driver circuit is configured to modulate a duty cycle of the second driving signal in order to modulate the second oscillation phase. ### Claim 11 (depends on 10) The oscillator system of claim 10, wherein the driver circuit is configured to modulate the duty cycle of the second driving signal to induce a periodic variance on the second oscillation frequency such that the second oscillation frequency varies over a frame period. ### Claim 12 (depends on 11) The oscillator system of claim 11, wherein the periodic variance is continuous. ### Claim 13 (depends on 11) The oscillator system of claim 11, wherein the periodic variance is a sine wave or a triangle wave. ### Claim 14 (depends on 1) The oscillator system of claim 1, wherein: the driver circuit is configured to modulate a duty cycle of the first driving signal in order to modulate the first oscillation phase, and the driver circuit is configured to modulate a duty cycle of the second driving signal in order to modulate the second oscillation phase. ### Claim 15 (depends on 14) The oscillator system of claim 14, wherein: the driver circuit is configured to modulate the duty cycle of the first driving signal to induce a first periodic variance on the first oscillation frequency such that the first oscillation frequency varies over a frame period, and the driver circuit is configured to modulate the duty cycle of the second driving signal to induce a second periodic variance on the second oscillation frequency such that the second oscillation frequency varies over the frame period, wherein the first periodic variance and the second periodic variance are waveforms having a same frequency with opposite phases. ### Claim 16 (depends on 1) The oscillator system of claim 1, wherein: the oscillator system is a Lissajous scanning system configured to scan a field-of-view, and the first oscillator structure and the second oscillator structure are configured to generate a Lissajous scanning pattern via respective oscillations. ### Claim 17 (depends on 16) The oscillator system of claim 16, wherein the Lissajous scanning pattern has a hexagonal pixel distribution pattern. ### Claim 18 A method of controlling an oscillator system, comprising: driving a first oscillator structure to oscillate about a first rotation axis at a first oscillation frequency; driving a second oscillator structure to oscillate about a second rotation axis at a second oscillation frequency; generating a first driving signal to drive an oscillation of the first oscillator structure with a first oscillation phase and the first oscillation frequency; generating a second driving signal to drive an oscillation of the second oscillator structure with a second oscillation phase and the second oscillation frequency, wherein the first oscillation frequency and the second oscillation frequency have a variable frequency ratio with respect to each other that varies over time; and modulating at least one of the first oscillation phase or the second oscillation phase to modulate the variable frequency ratio. ### Claim 19 An oscillator system, comprising: an oscillator structure configured to oscillate about a first rotation axis at a first oscillation frequency and oscillate about a second rotation axis at a second oscillation frequency; and a driver circuit configured to generate a first driving signal to drive a first oscillation of the oscillator structure about the first rotation axis with a first oscillation phase and the first oscillation frequency, and generate a second driving signal to drive a second oscillation of the oscillator structure about the second rotation axis with a second oscillation phase and the second oscillation frequency, wherein the first oscillation frequency and the second oscillation frequency have a variable frequency ratio with respect to each other that varies over time, wherein the driver circuit is configured to modulate at least one of the first oscillation phase or the second oscillation phase to modulate the variable frequency ratio. ### Claim 20 (depends on 19) The oscillator system of claim 19, wherein the driver circuit comprises a master control circuitry configured to generate the first driving signal and generate at least one synchronization signal, and a slave control circuitry configured to generate the second driving signal based on the at least one synchronization signal. ### Claim 21 (depends on 20) The oscillator system of claim 20, wherein the at least one synchronization signal includes a frame synchronization signal configured to synchronize a start of a frame period for both the first oscillation and the second oscillation. ### Claim 22 (depends on 20) The oscillator system of claim 20, wherein the at least one synchronization signal includes a phase synchronization signal configured to synchronize a rotation angle of the second oscillation with expected zero-crossing times. ### Claim 23 (depends on 22) The oscillator system of claim 22, wherein: the master control circuit is configured to receive a constant phase shift parameter and generate the phase synchronization signal based on the constant phase shift parameter. ### Claim 24 (depends on 23) The oscillator system of claim 23, wherein the slave control circuitry is configured to continuously phase shift the expected zero-crossing times of the second oscillation with respect to expected zero-crossing times of the first oscillation over a frame period based on the phase synchronization signal. ### Claim 25 (depends on 23) The oscillator system of claim 23, wherein the slave control circuitry is configured to constantly change a phase shift of the second oscillation with respect to the first oscillation based on the phase synchronization signal. ### Claim 26 (depends on 22) The oscillator system of claim 22, wherein: the slave control circuitry comprises a phase detector, wherein the phase detector is configured to receive the phase synchronization signal, a measurement signal indicating measured zero-crossing times of the second oscillation, and a phase modulation signal indicating a phase modulation, and generate a modulated phase error signal based thereon wherein the slave control circuitry is configured to modulate a duty cycle of the second driving signal based on the modulated phase error signal. ### Claim 27 (depends on 19) The oscillator system of claim 19, wherein the driver circuit is configured to modulate a duty cycle of the second driving signal in order to modulate the second oscillation phase. ### Claim 28 (depends on 27) The oscillator system of claim 27, wherein the driver circuit is configured to modulate the duty cycle of the second driving signal to induce a periodic variance on the second oscillation frequency such that the second oscillation frequency varies over a frame period. ### Claim 29 (depends on 28) The oscillator system of claim 28, wherein the periodic variance is continuous. ### Claim 30 (depends on 28) The oscillator system of claim 28, wherein the periodic variance is a sine wave or a triangle wave. ### Claim 31 (depends on 19) The oscillator system of claim 19, wherein: the driver circuit is configured to modulate a duty cycle of the first driving signal in order to modulate the first oscillation phase, and the driver circuit is configured to modulate a duty cycle of the second driving signal in order to modulate the second oscillation phase. ### Claim 32 (depends on 31) The oscillator system of claim 31, wherein: the driver circuit is configured to modulate the duty cycle of the first driving signal to induce a first periodic variance on the first oscillation frequency such that the first oscillation frequency varies over a frame period, and the driver circuit is configured to modulate the duty cycle of the second driving signal to induce a second periodic variance on the second oscillation frequency such that the second oscillation frequency varies over the frame period, wherein the first periodic variance and the second periodic variance are waveforms having a same frequency with opposite phases. ### Claim 33 (depends on 19) The oscillator system of claim 19, wherein: the oscillator system is a Lissajous scanning system configured to scan a field-of-view, and the first oscillation and the second oscillation are configured to generate a Lissajous scanning pattern via respective oscillations. ### Claim 34 (depends on 33) The oscillator system of claim 33, wherein the Lissajous scanning pattern has a hexagonal pixel distribution pattern. ### Claim 35 A method of controlling an oscillator structure, comprising: driving the oscillator structure to oscillate about a first rotation axis at a first oscillation frequency and to oscillate about a second rotation axis at a second oscillation frequency; generating a first driving signal to drive a first oscillation of the oscillator structure about the first rotation axis with a first oscillation phase and the first oscillation frequency; generating a second driving signal to drive a second oscillation of the oscillator structure about the second rotation axis with a second oscillation phase and the second oscillation frequency, wherein the first oscillation frequency and the second oscillation frequency have a variable frequency ratio with respect to each other that varies over time; and modulating at least one of the first oscillation phase or the second oscillation phase to modulate the variable frequency ratio.