Drive device, driving method and corresponding computer program, particularly for a scanning mirror

Abstract

Disclosed is a drive device including a movable portion, a driver, a detector, and a drive controller. The driver receives a drive signal including multiple first frequency components. The drive controller decomposes a detection signal output from the detector into multiple second frequency components (S14), determines whether the second frequency components match target frequency components, identifies a specific frequency component that does not match the target frequency components (S15), corrects amplitude and phase of the multiple first frequency components to be matched with the amplitude and the phase of one of the target frequency components (S16), and outputs the corrected drive signal including the multiple first frequency components to control the driver. For example, the movable portion is a scanning mirror, the driver and detector are piezoelectric, and the controller executes feedback control.

Description

FN202501267[DESCRIPTION][Title of Invention]DRIVE DEVICE, DRIVING METHOD, AND RECORDING MEDIUM [Technical Field]

[0001] The present disclosure relates to a drive device, a driving method, and a recording medium. [Background Art]

[0002] For example, there is known a mirror device that includes a mirror having a reflecting surface that reflects incident light and being rotatable around a first axis and a second axis perpendicular to each other, a first actuator that applies rotational torque around the first axis to the mirror to rotate the mirror around the first axis, and a second actuator that applies rotational torque around the second axis to the mirror to rotate the mirror around the second axis (for example, see PTL 1).[Citation List][Patent Literature]

[0003] [PTL 1]Japanese Unexamined Patent Application Publication No. 2023-001729 [Summary of Invention] [Technical Problem]

[0004] When a drive unit is controlled using a drive signal including multiple frequency components, there is room for improvement in control accuracy.The present disclosure described herein improves control accuracy in a drive device that controls a drive unit using a drive signal including multiple frequency components.[Solution to Problem]

[0005] According to one aspect of the present disclosure, a drive device includes a movable portion; a driver; a detector; and a drive controller. The driver receives a drive signal including multiple first frequency components and drives the movable portion based on the drive signal received by the driver. The detector detects a displacement of the movable portion and outputs a detection signal based on the displacement of the movable portion detected by the detector. The drive controller decomposes the detection signal output from the detector into multiple second frequency components; determines whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifies a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; corrects the amplitude value and the phase value of the multipleFN202501267 first frequency component to be matched with the amplitude value and the phase value of one of the target frequency components; and outputs, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver.According to one aspect of the present disclosure, a driving method includes receiving a drive signal including multiple first frequency components; driving a movable portion based on the drive signal received by a driver; detecting a displacement of the movable portion by a detector; outputting a detection signal based on the displacement of the movable portion detected by the detector; decomposing a detection signal output from a detector into multiple second frequency components; determining whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifying a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correcting the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and outputting, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver.According to one aspect of the present disclosure, a recording medium carries computer readable codes which, when executed by a computer system, cause the computer system to carry out control processing of decomposing a detection signal output from a detector into multiple second frequency components; determining whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifying a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correcting the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and outputting, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver. [Advantageous Effects of Invention]

[0006] With the aspects of the present disclosure, the control accuracy can be increased in the drive device that controls the drive unit using the drive signal including the multiple frequency components.[Brief Description of Drawings]

[0007] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.FIG. l is a plan view illustrating a drive device according to a first embodiment.FN202501267FIG. 2 is an end view of the drive device along a second axis in FIG. 1 according to the first embodiment.FIG. 3 is a sectional view illustrating a section cut along line III-III in FIG. 1 according to the first embodiment.FIG. 4 is a plan view illustrating a drive device according to a second embodiment.FIG. 5 is a block diagram illustrating the hardware configuration of the drive device according to the second embodiment.FIG. 6 is a block diagram illustrating the functional configuration of a control device according to the second embodiment.FIG. 7 is a waveform diagram presenting drive signals for spiral scanning according to the second embodiment.FIG. 8 is a waveform diagram presenting a drive signal with a basic period to be applied to a first piezoelectric drive unit according to the second embodiment.FIG. 9 is a graph presenting the ratio of the amplitude increase term to the amplitude decrease term and the proportion of the cavity diameter to the entire angle of view according to the second embodiment.FIG. 10 is a diagram illustrating the trajectory of light when drive signals for spiral scanning are input according to the second embodiment.FIG. 11 A is a graph presenting the relationship between the drive frequency and the oscillation angle of the mirror.FIG. 1 IB is a graph presenting the relationship between the drive frequency and the amplitude of the input voltage according to the second embodiment.FIG. 12 illustrates graphs presenting an example (case 1) of the transition of the amplitude of each frequency component in a correction process for an input waveform.FIG. 13 illustrates graphs presenting an example (case 2) of the transition of the amplitude of each frequency component in a correction process for an input waveform.FIG. 14 is a flowchart presenting a processing procedure of feedback control executed by the control device according to the second embodiment.FIG. 15 is a schematic diagram illustrating an example of an optical scanning system.FIG. 16 is a diagram illustrating the hardware configuration of the example of the optical scanning system.FIG. 17 is a block diagram illustrating the functional configuration of an example of a control device.FIG. 18 is a flowchart presenting an example of a processing procedure executed in the optical scanning system.FIG. 19 is a schematic diagram illustrating an example of a vehicle with a head-up display mounted.FIG. 20 is a schematic diagram illustrating an example of the head-up display.FIG. 21 is a perspective view illustrating an example of an image forming apparatus with an optical writing device mounted.FN202501267FIG. 22 is a schematic diagram illustrating an example of the optical writing device.FIG. 23 is a schematic diagram illustrating an example of a vehicle with a LiDAR device mounted.FIG. 24 is a schematic diagram illustrating an example of the vehicle with the LiDAR device mounted.FIG. 25 is a schematic sectional diagram illustrating an example of the LiDAR device.FIG. 26 is a schematic diagram illustrating an example of a laser headlamp.FIG. 27 is a perspective view illustrating an example of a head-mounted display.FIG. 28 is a schematic sectional diagram partially illustrating the example of the headmounted display.FIG. 29 is a schematic diagram illustrating the configuration of an example of a pupil or cornea position detection apparatus.FIG. 30 is a schematic diagram illustrating the configuration of an example of the pupil or cornea position detection apparatus.The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. [Description of Embodiments]

[0008] In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.Referring now to the drawings, embodiments of the present disclosure are described below.As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.Embodiments for implementing the disclosure are described below referring to the drawings. Like reference signs are applied to identical or corresponding components throughout the drawings and redundant description may be omitted.

[0009] In the description of the embodiments of the present disclosure, terms such as rotation, oscillation, and movement (movable) are synonymous. In the drawings, directions may be indicated by an X-axis direction, a Y-axis direction, and a Z-axis direction perpendicular to each other. The Z-axis direction extends in a stacking direction of layers in a piezoelectric drive unit. A view in the Z-axis direction may be referred to as a "plan view." In each of the drawings, a portion that is not a section may be hatched.

[0010] FN202501267The X-axis direction includes a direction indicated by an arrow and a direction opposite thereto. In the X-axis direction, a direction in which an arrow is directed may be referred to as a +X direction, and a direction opposite to the +X direction may be referred to as a -X direction. The Y-axis direction includes a direction indicated by an arrow and a direction opposite thereto. In the Y-axis direction, a direction in which an arrow is directed may be referred to as a +Y direction, and a direction opposite to the +Y direction may be referred to as a -Y direction. The Z-axis direction includes a direction indicated by an arrow and a direction opposite thereto. In the Z-axis direction, a direction in which an arrow is directed may be referred to as a +Z direction, and a direction opposite to the +Z direction may be referred to as a -Z direction. These directions do not limit the orientation of a drive device 13, and the orientation of the drive device 13 can be desirably determined. The drive device may be referred to as an "optical deflector." The drive device may be referred to as a "movable device."

[0011] [Drive Device 13 According to First Embodiment]A drive device 13 according to a first embodiment will be described referring to FIGS. 1 to 3. FIG. 1 is a plan view illustrating the drive device 13 according to the first embodiment of the present disclosure. FIG. 2 is an end view of the drive device 13 along a second axis in FIG. 1. FIG. 3 is a sectional view illustrating a section cut along line III-III in FIG. 1.

[0012] As illustrated in FIG. 1, the drive device 13 includes a mirror 101, first drive units 110a and 110b (or drivers), a first support frame 120, second drive units 130a and 130b, a second support frame 140, an electrode connecting part 150, and a control device 11.

[0013] [Mirror 101]The mirror 101 has a reflecting surface 14 that reflects incident light. The mirror 101 is an example of a movable portion. Each of the first drive units 110a and 110b is connected to the mirror 101 to rotate the mirror 101 around a first axis parallel to the Y-axis. The first support frame 120 supports the mirror 101 and the first drive units 110a and 110b.

[0014] The second drive units 130a and 130b are connected to the first support frame 120 to rotate the mirror 101 and the first support frame 120 around a second axis parallel to the X-axis. The second support frame 140 supports the second drive units 130a and 130b. The electrode connecting part 150 is electrically connected to the first drive units 110a and 110b, the second drive units 130a and 130b, and the control device 11.

[0015] The drive device 13 is formed by, for example, etching one silicon on insulator (SOI) substrate. The reflecting surface 14, first piezoelectric drive units 112a and 112b, second piezoelectric drive units 13 la to 13 If, second piezoelectric drive units 132a to 132f, and the electrode connecting part 150 are provided on the SOI substrate. The reflecting surface 14,FN202501267 the first piezoelectric drive units 112a and 112b, the second piezoelectric drive units 13 la to 13 If, the second piezoelectric drive units 132a to 132f, and the electrode connecting part 150 described above may be formed after the SOI substrate is formed or may be formed while the SOI substrate is formed.

[0016] As illustrated in FIGS. 2 and 3, the SOI substrate on which the drive device 13 is formed includes a silicon supporting layer 161 made of single crystal silicon (Si), a silicon oxide layer 162 formed on the silicon supporting layer 161 (on the +Z side), and a silicon active layer 163 made of single crystal silicon and formed on the silicon oxide layer 162. The silicon oxide layer 162 is referred to also as a buried oxide (BOX) layer.

[0017] The member made of the silicon active layer 163 has a function as an elastic portion having elasticity.

[0018] In some embodiments, the SOI substrate has, for example, a curvature. In other words, the SOI substrate does not have to be planar. The member used to form the drive device 13 is not limited to the SOI substrate, and may be a substrate that can be integrally formed by etching or the like and partially has elasticity.

[0019] The mirror 101 includes, for example, a circular mirror base 102 and the reflecting surface 14 that is formed on the +Z surface of the mirror base 102. The mirror base 102 includes, for example, the silicon active layer 163. The reflecting surface 14 includes, for example, a thin metal film containing aluminum (Al), gold (Au), or silver (Ag).

[0020] The mirror 101 includes a movable thick portion 103 for strengthening the mirror 101 on the — Z surface of the mirror base 102. The movable thick portion 103 includes, for example, the silicon supporting layer 161 and the silicon oxide layer 162 to prevent the distortion of the reflecting surface 14 due to the movement.

[0021] [First Drive Units 110a and 110b]As illustrated in FIG. 1, the first drive units 110a and 110b include torsion bars Illa and 111b and the first piezoelectric drive units 112a and 112b.

[0022] One end of the torsion bar 11 la is connected to the mirror 101. One end of the torsion bar 11 lb is connected to the mirror 101. The torsion bars Illa and 111b are supports that extend in the Y-axis direction and elastically support the mirror 101.

[0023] [First Piezoelectric Drive Units 112a and 112b]The first piezoelectric drive units 112a and 112b are located apart from each other in the Y- axis direction and extend in the X-axis direction. The first piezoelectric drive unit 112aFN202501267 connects the torsion bar Illa and the inner peripheral portion of the first support frame 120 to each other. The first piezoelectric drive unit 112b connects the torsion bar 111b and the inner peripheral portion of the first support frame 120 to each other. The first piezoelectric drive units 112a and 112b are drive beams that deform the torsion bars Illa and 111b to rotate the mirror 101 around the first axis. The first axis is a predetermined rotation axis. The first drive units 110a and 110b include detective piezoelectric elements 160a and 160b.

[0024] As illustrated in FIG. 3, the torsion bars Illa and 111b each include the silicon active layer 163. The first piezoelectric drive units 112a and 112b each include a lower electrode 301, a piezoelectric portion 302, and an upper electrode 303. The lower electrode 301, the piezoelectric portion 302, and the upper electrode 303 are stacked in this order on the +Z surface of the silicon active layer 163 serving as the elastic portion.For example, each of the upper electrode 303 and the lower electrode 301 contains gold (Au) or platinum (Pt).For example, the piezoelectric portion 302 contains lead zirconate titanate (PZT) as a piezoelectric material.

[0025] As illustrated in FIGS. 1 and 3, the first support frame 120 includes the silicon supporting layer 161, the silicon oxide layer 162, and the silicon active layer 163. The first support frame 120 is a rectangular support formed to surround the mirror 101.

[0026] [Second Drive Units 130a and 130b]The second drive unit 130a includes multiple second piezoelectric drive units 131a to 13 If connected so as to be folded back. The second drive unit 130b includes multiple second piezoelectric drive units 132a to 132f connected so as to be folded back. One end of each of the second drive units 130a and 130b is connected to the outer peripheral portion of the first support frame 120, and another end of each of the second drive units 130a and 130b is connected to the inner peripheral portion of the second support frame 140.

[0027] The connecting portion at which the one end of the second drive unit 130a is connected to the first support frame 120 and the connecting portion at which the one end of the second drive unit 130b is connected to the first support frame 120 are point-symmetrical with respect to the center of the reflecting surface 14. The connecting portion at which the other end of the second drive unit 130a is connected to the second support frame 140 and the connecting portion at which the other end of the second drive unit 130b is connected to the second support frame 140 are point-symmetrical with respect to the center of the reflecting surface 14.

[0028] [Second Piezoelectric Drive Units 13 la to 13 If and 132a to 132f]FN202501267As illustrated in FIG. 2, the second piezoelectric drive units 13 la to 13 If and 132a to 132f each include a lower electrode 201, a piezoelectric portion 202, and an upper electrode 203. The lower electrode 201, the piezoelectric portion 202, and the upper electrode 203 are stacked in this order on the +Z surface of the silicon active layer 163 serving as the elastic portion. For example, each of the upper electrode 203 and the lower electrode 201 contains gold (Au) or platinum (Pt). For example, the piezoelectric portion 202 contains lead zirconate titanate (PZT) as a piezoelectric material.

[0029] As illustrated in FIGS. 1 and 2, the second support frame 140 includes the silicon supporting layer 161, the silicon oxide layer 162, and the silicon active layer 163. The second support frame 140 is a rectangular support formed to surround the mirror 101, the first drive units 110a and 110b, the first support frame 120, and the second drive units 130a and 130b. In other words, the mirror 101, the first drive units 110a and 110b, the first support frame 120, and the second drive units 130a and 130b are located inside the second support frame 140.

[0030] [Electrode Connecting Part 150]Multiple electrode connecting parts 150 are formed on the +Z surface of the second support frame 140. The upper electrodes 303 and the lower electrodes 301 of the first piezoelectric drive units 112a and 112b are electrically connected to the multiple electrode connecting parts 150. The upper electrodes 203 and the lower electrodes 201 of the second piezoelectric drive units 13 la to 13 If and 132a to 132f are connected to the multiple electrode connecting parts 150. The control device 11 is connected to the multiple electrode connecting parts 150. The upper electrodes 303, the lower electrodes 301, the upper electrodes 203, the lower electrodes 201, and the control device 11 are electrically connected to the multiple electrode connecting parts 150 via electrode wiring. The electrode wiring may be made of, for example, aluminum (Al). For example, a signal voltage is applied to the lower electrodes 201, and the upper electrodes 203 are grounded (GND). For example, a signal voltage is applied to the lower electrodes 301, and the upper electrode 303 are grounded (GND).

[0031] Each of the upper electrodes 203 and the lower electrodes 201 may be directly connected to the electrode connecting parts 150. Alternatively, in some embodiments, the upper electrodes 203 and the lower electrodes 201 may be indirectly connected to the electrode connecting parts 150 through a wire connecting a pair of electrodes. Each of the upper electrodes 303 and the lower electrodes 301 may be directly connected to the electrode connecting parts 150. Alternatively, in some embodiments, the upper electrodes 303 and the lower electrodes 301 may be indirectly connected to the electrode connecting parts 150 through a wire connecting a pair of electrodes.

[0032] While each piezoelectric portion 202 is formed on one surface (the +Z surface) of the silicon active layer 163 serving as the elastic portion in the present embodiment, the piezoelectricFN202501267 portion 202 may be provided on another surface (for example, the -Z surface) of the elastic portion or may be provided on both the one surface and the other surface of the elastic portion.

[0033] The shape of the drive device 13 is not limited to the shape of the above-described embodiment as long as the drive device 13 can drive the mirror 101 around the first axis or the second axis. For example, the torsion bars Illa and 111b and the first piezoelectric drive units 112a and 112b may include shapes having curvatures.

[0034] The drive device 13 may be of a cantilever type in which the first piezoelectric drive units 112a and 112b extend from the torsion bars Illa and 11 lb in the +X direction. The drive device 13 is not limited to a drive device of the above-described type. The drive device 13 may be of any type as long as the drive device 13 can rotate the mirror 101 with the piezoelectric portion 202 to which a drive voltage is applied. The drive device 13 may be of, for example, a both-end supported (double supported) type.

[0035] Further, an insulating layer made of a silicon oxide film may be formed on at least one of the +Z surfaces of the upper electrodes 303 of the first drive units 110a and 110b, the +Z surface of the first support frame 120, the +Z surfaces of the upper electrodes 203 of the second drive units 130a and 130b, and the +Z surface of the second support frame 140.

[0036] With the drive device 13 having this structure, the electrode wiring is provided on the insulating layer, and the insulating layer is partially removed or the insulating layer is not partially formed as an opening at the connecting spot at which the upper electrode 203, the upper electrode 303, the lower electrode 201, or the lower electrode 301 is connected to the electrode wiring. This configuration increases the degree of flexibility in design of the first drive units 110a and 110b, the second drive units 130a and 130b, and the electrode wiring and also prevents short circuiting due to the electrodes contacting each other. The silicon oxide film also has a function as an anti -refl ection material.

[0037] [First Piezoelectric Drive Units 112a and 112b]The first piezoelectric drive unit 112a, which is provided in the first drive unit 110a, deforms the first drive unit 110a in response to an applied drive voltage. The first piezoelectric drive unit 112b, which is provided in the first drive unit 110b, deforms the first drive unit 110b in response to an applied drive voltage.

[0038] [Detective Piezoelectric Elements 160a and 160b]The detective piezoelectric element 160a is provided in proximity to the first piezoelectric drive unit 112a. The detective piezoelectric element 160b is provided in proximity to the first piezoelectric drive unit 112b.FN202501267

[0039] The detective piezoelectric element 160a generates a detection signal in response to the deformation of the first drive unit 110a (i.e., the piezoelectric effects), and outputs the detection signal to the control device 11 via the electrode connecting parts 150. The detective piezoelectric element 160b generates a detection signal in response to the deformation of the first drive unit 110b (i.e., the piezoelectric effects), and outputs the detection signal to the control device 11 via the electrode connecting parts 150.

[0040] [Drive Device 13B According to Second Embodiment]Next, a drive device 13B according to a second embodiment will be described. FIG. 4 is a plan view illustrating the drive device 13B according to the second embodiment. In the description of the second embodiment, a description similar to that of the drive device 13 according to the above-described first embodiment may be omitted. The driving method of the drive body (drive unit) is not limited to piezoelectric driving. The driving method of the drive body may be electrostatic driving, electromagnetic driving, or thermoelectric driving.

[0041] [First Drive Units 110a to HOd]The drive device 13B includes four first drive units 110a to HOd and can two-dimensionally deflect light. The drive device 13B can execute vector scanning, Lissajous scanning, and spiral scanning. The first drive units 110a to HOd are an example of a drive unit.

[0042] In the drive device 13B, a mirror 101 and the first drive units 110a to HOd are formed of the same substrate. While the mirror 101 and the first drive units 110a to HOd can be implemented by, for example, a silicon active layer of an SOI substrate, the configurations in the plane and in the thickness direction are not limited to those described in the embodiment.

[0043] The drive device 13B includes the mirror (movable portion) 101, a support frame 140, and the first drive units 110a to 1 lOd. The support frame 140 may be a frame having a rectangular shape in a plan view. The rectangular frame has sides along the X-axis direction and the Y- axis direction in a plan view.

[0044] The first drive units 110a to HOd are located in correspondence with the corners of the support frame 140. The first drive unit 110a includes a torsion bar Illa and a piezoelectric drive unit 112a. The piezoelectric drive unit 112a is formed to have a rectangular shape in a plan view. The torsion bar Illa protrudes from the piezoelectric drive unit 112a toward the mirror 101.

[0045] Similarly, the first drive unit 110b includes a torsion bar 111b and a piezoelectric drive unit 112b. The first drive unit 110c includes a torsion bar 111c and a piezoelectric drive unit 112c. The first drive unit HOd includes a torsion bar 11 Id and a piezoelectric drive unit 112d.FN202501267

[0046] [Detective Piezoelectric Elements 160a to 160d]A detective piezoelectric element 160a is provided in proximity to the first piezoelectric drive unit 112a. The detective piezoelectric element 160a extends in the longitudinal direction of the torsion bar Illa. A detective piezoelectric element 160b is provided in proximity to the first piezoelectric drive unit 112b. The detective piezoelectric element 160b extends in the longitudinal direction of the torsion bar 111b. A detective piezoelectric element 160c is provided in proximity to the first piezoelectric drive unit 112c. The detective piezoelectric element 160c extends in the longitudinal direction of the torsion bar 111c. A detective piezoelectric element 160d is provided in proximity to the first piezoelectric drive unit 112d. The detective piezoelectric element 160d extends in the longitudinal direction of the torsion bar 11 Id.

[0047] The detective piezoelectric element 160a generates a detection signal in response to the deformation of the first drive unit 110a (i.e., the piezoelectric effects). The detective piezoelectric element 160b generates a detection signal in response to the deformation of the first drive unit 110b (i.e., the piezoelectric effects). The detective piezoelectric element 160c generates a detection signal in response to the deformation of the first drive unit 110c (i.e., the piezoelectric effects). The detective piezoelectric element 160d generates a detection signal in response to the deformation of the first drive unit HOd (i.e., the piezoelectric effects). The detective piezoelectric elements 160a to 160d output the detection signals to a control device 11 via an electrode connecting part 150.

[0048] [Control Device 11]Next, the control device 11 of the drive device 13B according to the second embodiment will be described. FIG. 5 is a block diagram illustrating the hardware configuration of the drive device 13B. As illustrated in FIG. 5, the drive device 13B includes the control device 11. For example, the control device 11 is an electronic circuit unit including a central processing unit (CPU) 20 and a field-programmable gate array (FPGA) 23. The control device 11 includes the CPU 20, a random-access memory (RAM) 21, a read-only memory (ROM) 22, the FPGA 23, an external interface (I / F) 24, and a drive-device driver 26. The first piezoelectric drive units 112a to 112d and the detective piezoelectric elements 160a to 160d are electrically connected to the control device 11.

[0049] The CPU 20 is an arithmetic device that reads programs and data from storage devices, such as the ROM 22, into the RAM 21 and processes the programs and data to control and implement the functions of the entire control device 11. The RAM 21 is a volatile storage device that temporarily holds a program and data. The ROM 22 is a nonvolatile storage device that can store a program and data even when the power is switched off. The ROM 22FN202501267 stores data and a processing program that is executed by the CPU 20 to control each function of the control device 11.

[0050] The FPGA 23 is a circuit that outputs a proper control signal to the drive-device driver 26 in accordance with the processing performed by the CPU 20. For example, the external I / F 24 is an interface with respect to an external device or a network. The external device may be, for example, a host device such as a personal computer (PC); or a storage device, such as a universal serial bus (USB) memory, a secure digital (SD) card, a compact disk (CD), a digital versatile disk (DVD), a hard disk drive (HDD), or a solid state drive (SSD). The network may be, for example, a controller area network (CAN) of a vehicle, a local area network (LAN), or the Internet. The external I / F 24 can have any configuration that can achieve connection to an external device or communication with an external device. The external I / F 24 may be provided for each external device.

[0051] [Drive-device Driver 26]The drive-device driver 26 is an electric circuit that outputs a drive signal to the first piezoelectric drive units 112a to 112d in accordance with the received control signal. The drive signal may be a drive voltage.

[0052] The CPU 20 acquires optical scanning information from an external device or a network through the external I / F 24. As far as the CPU 20 can acquire the optical scanning information, the optical scanning information may be stored in the ROM 22 or the FPGA 23 in the control device 11. Alternatively, a storage device such as an SSD may be additionally included in the control device 11, and the optical scanning information may be stored in the storage device.

[0053] The optical scanning information includes information indicating how to perform optical scanning on a target surface 15. For example, the optical scanning information may be image data when an image is to be displayed by optical scanning. For example, the optical scanning information is writing data indicating the writing sequence and the writing locations when optical writing is performed by optical scanning. For example, the optical scanning information is irradiation data indicating the irradiation timing and the irradiation range of the light for object recognition when object recognition is performed by optical scanning.

[0054] The control device 11 enables the functional configuration described below by using instructions from the CPU 20 and the hardware configuration.

[0055] [Functional Configuration of Control Device 11]Next, the functional configuration of the control device 11 will be described. FIG. 6 is a block diagram illustrating the functional configuration of the control device 11. The controlFN202501267 device 11 includes a controller 30 and a drive-signal output unit 31. For example, the controller 30 is implemented by the CPU 20 or the FPGA 23. The controller 30 acquires optical scanning information from an external device, converts the optical scanning information into a control signal, and outputs the control signal to the drive-signal output unit 31. For example, the controller 30 acquires image data as the optical scanning information from an external device, generates a control signal from the image data through predetermined processing, and outputs the control signal to the drive-signal output unit 31. The drive-signal output unit 31 is implemented by, for example, the drive-device driver 26. The drive-signal output unit 31 outputs a drive signal to the first piezoelectric drive units 112a to 112d based on the received control signal.

[0056] The drive signal is a signal for controlling the driving of the first piezoelectric drive units 112a to 112d.For example, the drive signal is a drive voltage used to control the timing at which the reflecting surface 14 is moved and the movable range of the reflecting surface 14. An example of the drive signal will be described later.

[0057] [First Arithmetic Unit 32]A first arithmetic unit 32 decomposes a detected output into frequency components. The "output" referred to herein may be a displacement of the mirror 101 serving as a movable portion. The detective piezoelectric elements 160a to 160d serving as a detection unit detect the output of the mirror 101. The detective piezoelectric elements 160a to 160d detect the displacement of the mirror 101. The detective piezoelectric elements 160a to 160d output detection signals relating to the output of the mirror 101 to the control device 11. The signals relating to the output of the mirror 101 may be referred to as an "output signal."

[0058] The first arithmetic unit 32 decomposes the detection signals into frequency components and acquires the amplitude and phase information of each frequency component. The first arithmetic unit 32 can perform fast Fourier transformation (FFT) processing on the detection signals.

[0059] [Second Arithmetic Unit 33]A second arithmetic unit 33 updates the drive signal based on information of the first arithmetic unit 32. The information of the first arithmetic unit 32 includes information relating to the amplitude and information relating to the phase of each frequency component.

[0060] The second arithmetic unit 33 may determine whether the amplitude and the phase of each frequency component of the detection signals meet a predefined desired set. The "desired set" may be a combination of the amplitude and the phase.

[0061] FN202501267The second arithmetic unit 33 can correct a drive waveform based on an analysis result. The "drive waveform" referred to herein may be a drive waveform of a drive signal that is a source of the output of the mirror 101. The "analysis result" may be a result of frequency analysis.

[0062] [Output of Drive Unit]The output of the drive unit represents outputs of the first piezoelectric drive units 112a and 112b and the second piezoelectric drive units 131a to 13 If and 132a to 132f serving as a drive unit, and may be a displacement of the mirror 101 serving as the movable portion. The output of the drive unit may be expressed by, for example, Expression (1) below.Axsin(27t*fi) + Axsin(27txf2) ... (1)In Expression (1), reference character "A" represents a positive constant and represents an amplitude of the output of the drive unit. Reference character "K" represents a coefficient. Reference characters "fi" and "fi" represent frequencies. Reference character "K" may be denoted as "pi."

[0063] The second arithmetic unit 33 may determine whether the output of the drive unit has a function form as expected based on the detection signal. The "function form" may be Expression (1) described above. "As expected" may be the same as what is set in advance.

[0064] The output of the drive unit may be expressed by, for example, Expression (2) below. Ai><sin(27txfi + i) + A2xsin(27txf2 + 2) ... (2)In Expression (2), reference characters "Ai" and "A2" represent positive constants and represent amplitudes of the output of the drive unit. Reference characters "Oi" and "<[>2" may represent phase values. Reference character "O" may be denoted as "phi."

[0065] The second arithmetic unit 33 may determine whether the output of the drive unit satisfies Expression (2) described above based on the detection signal. When the output of the drive unit satisfies Expression (2) described above, for example, the second arithmetic unit 33 can update the input amplitude of the frequency component of fi such that the amplitude ratio of the frequency components is 1 : 1.

[0066] [Control Performed by Control Device 11]Next, control performed by the control device 11 will be described. The control device 11 applies a drive voltage to the piezoelectric portions 302 of the first piezoelectric drive units 112a to 112d.

[0067] When a positive or negative voltage is applied in the polarization direction, the piezoelectric portions 302 deform (for example, expand and contract) in proportion to the potential of the applied voltage and exhibits so-called inverse piezoelectric effects. The first drive units 110a to HOd move the mirror 101 using the inverse piezoelectric effects.FN202501267

[0068] In this case, the angle defined by the reflecting surface 14 of the mirror 101 with respect to the XY plane when the reflecting surface 14 is inclined to the +Z direction or -Z direction with respect to the XY plane is referred to as an "oscillation angle." The +Z direction is referred to as a positive oscillation angle and the -Z direction is referred to as a negative oscillation angle.

[0069] [Driving of First Piezoelectric Drive Units 112a to 112d]When a drive voltage is applied to the piezoelectric portions 302 via the upper electrodes 303 and the lower electrodes 301, the piezoelectric portions 302 deform. With the effect of such deformation of the piezoelectric portions 302, the first piezoelectric drive units 112a to 112d bend and deform. As a result, a driving force acts on the mirror 101 via the torsion of the four torsion bars Illa to l lld so that the mirror 101 rotates around the Z-axis. The mirror 101 is driven by the first piezoelectric drive units 112a to 112d and rotates around the Z-axis. The control device 11 controls the drive voltage to be applied to the first piezoelectric drive units 112a to 112d.

[0070] The control device 11 applies drive voltages having a predetermined sine waveform to the first piezoelectric drive units 112a to 112d in parallel. With this configuration, the control device 11 can move the mirror 101 to rotate around the Z-axis with the periods of the drive voltages having the predetermined sine waveform.

[0071] The control device 11 can also control the displacements of the first drive units 110a to HOd based on information relating to the displacements of the first drive units 110a to 1 lOd acquired based on the detection signals output by the detective piezoelectric elements 160a to 160d.

[0072] For example, the frequency of the drive voltages may be substantially the same as the resonance frequency of the torsion bars Illa to 111b. When the resonance frequency of the torsion bars Illa to 111b is, for example, 20 kHz, the control device 11 applies drive voltages having the frequency of 20 kHz to the piezoelectric portions 302 and hence can cause mechanical resonance due to the torsion to occur in the torsion bars Illa to 111b. In this case, the control device 11 can cause the mirror 101 to resonantly oscillate at about 20 kHz.

[0073] For example, when an input signal is one sine wave in a linear system (a system including the drive device 13B), an output is one sine wave having the same frequency. The one sine wave serving as the input signal can be expressed by Expression (3) below. The one sine wave serving as the output can be expressed by Expression (4) below.Al_inxcos(27t*fxt + <bl) ... (3)Al out xcos(27txfxt + 2) ... (4)FN202501267In Expression (3), reference character " Ai in" represents a positive constant and represents an amplitude of the sine wave of the input signal. Reference character "K" represents a coefficient. Reference character "f1represents a frequency. Reference characters "Oi" and "<[>2" may represent phase values. In Expression (4), reference character "Ai out" represents a positive constant and represents an amplitude of the sine wave of the output signal. Reference character "in" represents an input, and reference character "out" represents an output.

[0074] However, the phase and the amplitude of the sine wave of the output vary depending on the resonance frequency and the Q value of the system and the frequency of the sine wave of the input signal. When an input signal is superimposition of multiple sine waves in a linear system, an output is the sum of outputs when the sine waves are independently input.

[0075] When the output is to be a certain periodic function (f(t)) with regard to these two characteristics, the periodic function is expanded into a Fourier series to obtain Expression (5) below. f(t) = Aixcos+ A2xcos(27t+ . (5)For the input, there is a problem with using the same function, and it is desirable to appropriately control the amplitude and the phase of each frequency component as in " An" to "An+i" and " n" to "n+i." When "An out" is to be output, "An in" is input.

[0076] The drive device 13B detects the output of the drive unit with the detection unit, decomposes the detected output into frequency components by the FFT, and acquires the amplitude and the phase of each frequency component. The output of the drive unit may be, specifically, the displacement of an actuator for rotating the mirror 101 serving as a micro-electromechanical systems (MEMS) mirror or the position of the laser beam reflected by the mirror 101.

[0077] For example, when a desired amplitude is A and a phase is for a certain frequency component, and when the detected amplitude and phase are A det and det, respectively, the control device 11 can execute feedback control such that the amplitude of the input signal is multiplied by (A / A det) and the phase of the input signal is increased by ( - det) based on the detected amplitude and phase. Reference character "A det" represents an amplitude of the detection signal. Reference character " det" represents a phase of the detection signal.

[0078] While the correction process is executed on all frequency components in control on the real time axis, the control device 11 executes control for each frequency component, and hence can perform control substantially independently for each frequency component.

[0079] FN202501267With a fixing device according to a comparative example, for example, test driving is executed to determine a coefficient for correcting a signal to be input to the drive unit. In contrast, with the feedback control executed by the control device 11, convergence of the output signal can be observed, and a change in environment or a change with time can be handled by the same method.

[0080] [Drive Signals for Spiral Scanning]FIG. 7 is a waveform diagram presenting drive signals for spiral scanning. In FIG. 7, the horizontal axis indicates the lapse of time, and the vertical axis indicates the normalized amplitude of the drive waveform. FIG. 7 presents respective drive signals to be applied to the first piezoelectric drive units 112a to 112d. The phases of the four drive signals supplied to the first piezoelectric drive units 112a to 112d are shifted from each other by 90 degrees.

[0081] [Amplitude Modulation]Next, amplitude modulation in a high-speed signal periodic waveform will be described. FIG. 8 is a waveform diagram presenting a drive signal with a basic period to be applied to the first piezoelectric drive unit 112a. In FIG. 8, the horizontal axis indicates the lapse of time, and the vertical axis indicates the normalized amplitude of the drive waveform. The drive signal presented in FIG. 8 includes a first term Ta, a second term Tb, and a third term Tc in this order in the basic period.

[0082] The first term Ta is a term in which the amplitude of the drive voltage continuously increases, and continues until the amplitude reaches the maximum. The second term Tb is a term in which the amplitude of the drive voltage continuously decreases. The third term Tc is a term in which the amplitude of the drive voltage is a predetermined value. The predetermined value of the amplitude in the third term Tc is less than or equal to the value of the smallest amplitude in the second term Tb immediately before the third term Tc. In the third term Tc, the amplitude of the drive voltage may be 0.

[0083] The drive signal includes a first waveform in the first term Ta. The drive signal includes a second waveform in the second term Tb. The drive signal includes a third waveform in the third term Tc. The phases of the drive signal of the first waveform and the second waveform may be the same phases or opposite phases. The third waveform may be a direct-current (DC) waveform. When the third waveform is a drive waveform in which the amplitude of the drive voltage is constant, the phase of the third waveform may be the same as or opposite to the phase of the second waveform.

[0084] The amplitude of the drive waveform preferably continuously changes from the first term Ta to the second term Tb. Similarly, the amplitude of the drive waveform preferably continuously changes from the second term Tb to the third term Tc. In the first term Ta, theFN202501267 amplitude of the drive waveform increases, the rotation of the reflecting surface 14 increases, and the energy of the resonance oscillation accumulates. In the second term Tb, the amplitude of the drive waveform decreases and the rotation of the reflecting surface 14 attenuates. In the second term Tb, the amplitude of the drive signal input to the piezoelectric drive unit 112a is smoothly decreased. In the third term Tc, a term in which the amplitude of the drive signal has the predetermined value continues for a certain period of time. The certain period of time is one period or more of the high-speed signal period.

[0085] [Advantageous Effects by Drive Signal]With the drive signal having the basic-period waveform including the first waveform whose amplitude continuously increases in the first term Ta, the second waveform whose amplitude continuously decreases in the second term Tb, and the third waveform whose amplitude is the predetermined value in the third term Tc, the rotation of the reflecting surface 14 can be attenuated toward the center O of angle of view without excessively increasing resonance energy in a period of time other than the effective scanning term. When the first term Ta is used as the effective scanning term in which an image is projected, by setting the first term Ta to be longer than the second term Tb, large resonance energy can be obtained and the angle of view can be increased. The "effective scanning term" is a term of a range in which the trajectory of light is plotted in a state in which the reflecting surface 14 is irradiated with light.

[0086] FIG. 9 is a graph presenting the ratio of the amplitude increase term to the amplitude decrease term and the proportion of the cavity diameter to the entire angle of view of the drive device 13B. In FIG. 9, when the length of the basic period and the length of the first term Ta serving as the amplitude increase term are constant, the horizontal axis indicates the length of the first term Ta / the length of the second term Tb, and the vertical axis indicates the proportion of the diameter of the cavity region to the entire angle of view. When the length of the second term Tb is short, that is, when the length of the third term Tc in which the amplitude has the predetermined value is long, the proportion of the cavity diameter to the entire angle of view is smaller than the value when the length of the second term Tb is long, that is, when the length of the third term Tc is short. "When the length of the basic period and the length of the first term Ta are constant" means that the proportion of the "first term Ta" to the "basic period" is constant and does not change.

[0087] When the proportion of the "first term Ta" to the "basic period" is constant, the resolution of the center O of angle of view can be increased by decreasing the second term Tb and increasing the third term Tc.With this configuration, the resolution of the trajectory of the light reflected by the reflecting surface 14 can be controlled by changing the proportion of the "third term Tc" to the "basic period."

[0088] FN202501267FIG. 10 is a diagram illustrating the trajectory of light when drive signals for spiral scanning are input. As illustrated in FIG. 10, when the drive signals for spiral scanning are input, the resolution in the vicinity of the center O of angle of view can be increased as compared to the resolution of the drive signal of the related art.

[0089] With the drive signals for spiral scanning, the amount of rotation of the mirror converges on the center O of angle of view, and hence spirals having an interval substantially equal to the interval of spirals in other regions can be plotted even in the vicinity of the center O of angle of view. With this configuration, the cavity diameter at the center O of angle of view can be reduced, and hence the resolution of an image formed on the irradiation surface can be increased using the light reflected by the reflecting surface 14.

[0090] The drive signal with the basic period includes the first waveform whose amplitude continuously increases in the first term Ta, the second waveform whose amplitude continuously decreases in the second term Tb after the first term Ta, and the third waveform whose amplitude has the predetermined value in the third term Tc after the second term Tb. The predetermined value of the amplitude of the third waveform is less than or equal to the value of the smallest amplitude of the second waveform in the second term Tb immediately before the third term Tc.

[0091] The drive device 13 applies the drive signals including the third waveform to the first drive units 110a to HOd, and hence can make the amount of rotation of the mirror 101 smaller than the amount of rotation at the end of the second term Tb.The drive device 13 can further reduce the rotation of the mirror 101. With this configuration, the amount of rotation of the mirror is likely to return to the angle of view of 0 within one period of the basic period, and hence the resolution in the vicinity of the center O of angle of view can be increased.

[0092] The amplitude of the third waveform in the third term Tc may be a predetermined value, and the predetermined value may be less than or equal to the value of the smallest amplitude of the second waveform in the second term Tb immediately before the third term Tc. As presented in FIG. 9, in the drive waveform according to the first embodiment, the amplitude of the third waveform in the third term Tc is less than or equal to the value of the smallest amplitude of the second waveform in the second term Tb. Since the amplitude of the third waveform is set to be less than or equal to the value of the smallest amplitude of the second waveform in the second term Tb immediately before the third term Tc, the rotation of the mirror 101 can be more efficiently reduced.

[0093] FN202501267The third waveform may be a DC waveform or have an amplitude of 0. When the third waveform is a DC waveform or has an amplitude of 0, the rotation of the mirror 101 can be more efficiently reduced.

[0094] The length of the second term Tb is preferably shorter than the length of the first term Ta. In other words, the length of the first term Ta is preferably longer than the length of the second term Tb. In the drive waveform according to the first embodiment, the first term Ta is longer than the second term Tb.

[0095] [Correction Process for Input Waveform (Case 1)]Next, a correction process for an input waveform (case 1) will be described. The control device 11 can correct and update the input waveform. FIG. 11 A is a graph presenting the relationship between the drive frequency and the oscillation angle of the mirror, and FIG. 11B is a graph presenting the relationship between the drive frequency and the amplitude of the input voltage. FIG. 12 illustrates graphs presenting an example (case 1) of the transition of the amplitude of each frequency component in the correction process for the input waveform.

[0096] In (a) to (f) of FIG. 12, sine waves SWfl, SWf2, and SWf3 having different frequencies are presented. Each of the input signal and the output signal is the sum of multiple frequency components. The sine waves SWfl, SWf2, and SWf3 are examples of frequency components. The "input signal" is a drive signal input from the control device 11 to the first piezoelectric drive units 112a to 112d. The "output signal" is a detection signal output from the detective piezoelectric elements 160a to 160d to the control device 11.

[0097] It is desirable to obtain, as the output signal, the ratio as follows: the amplitude value of the sine wave SWfl : the amplitude value of the sine wave SWf2: the amplitude value of the sine wave SWf3 = 3:2:4. This case will be described.

[0098] As presented in FIG. 11 A, regarding the relationship between the input voltage and the oscillation angle of the mirror 101, which varies depending on the drive frequency, a case where the frequency response characteristic of the MEMS is an upwardly convex function is assumed. The "frequency response of the MEMS" represents the amplitude of the oscillation of the mirror 101 when a sine wave having one frequency is input as a drive waveform to the first piezoelectric drive units 112a to 112d. Experimentally, the frequency of the input sine wave is swept, the frequency of the input sine wave is plotted on the horizontal axis, and the amplitude of the oscillation of the mirror 101 is plotted on the vertical axis. The amplitude increases near the resonance frequency of the MEMS (first piezoelectric drive units 112a to 112d), and the amplitude decreases away from the resonance frequency. This is expressed as "upward convex." When the MEMS (first piezoelectric drive units 112a to 112d) has aFN202501267 characteristic of not moving at all at a certain frequency, the function is a downwardly convex function.

[0099] The control device 11 sets a situation in which the frequency components (sine waves SWfl, SWf2, and SWf3) are located near the peaks of the frequency response characteristics as presented in FIG. 11B.

[0100] For example, the frequencies of the sine waves SWfl, SWf2, and SWf3 can be desirably set by the user using the drive device 13B. However, when the control device 11 is mounted on the drive device 13B that is a mass-produced product, it is advantageous to set the frequencies to fixed values because handling is easy.

[0101] In contrast, the first piezoelectric drive units 112a to 112d serving as the MEMS vary among individual units, and the positions of the frequencies of the sine waves SWfl, SWf2, and SWf3 are often different from the positions in FIG. 11B. For example, the sine wave SWf2 may be shifted from the peak, or the frequencies of all the sine waves SWfl, SWf2, and SWf3 may be located on the left of the peaks.

[0102] The drive device 13B according to the present embodiment can be applied basically regardless of the positions of the peaks and the positions of the frequencies. The drive device 13B is a technique that is widely applicable. The drive device 13B is a technique that is widely applicable regardless of the positions of the peaks and the positions of the frequencies.

[0103] An example in which the drive device 13B can be applied is not limited to the situation illustrated in FIG. 11B, and the drive device 13B can be applied in any situation.

[0104] In this case, even when the amplitude values of the frequency components of the input voltage (input signal) are set to 1 : 1 : 1, the amplitude values of the frequency components of the output signal do not have the ratio, and the amplitude values of the frequency components of the output signal have a ratio in the order of the amplitude value of the sine wave SWf2 > the amplitude value of the sine wave SWfl > the amplitude value of the sine wave SWf3.

[0105] First, the control device 11 receives the ratio = 3:2:4 of the amplitude values of the frequency components obtained as the output signal. "The ratio of the amplitude values of the frequency components (SWfl, SWf2, and SWf3)" may be referred to as an "amplitude ratio."

[0106] Here, it is assumed that an amplitude ratio = 2:2: 1 of the output signal is obtained due to the characteristics of the system. The "characteristics of the system" may be "characteristics of the system including the drive device 13B." It is assumed that the amplification rate at thisFN202501267 time satisfies the amplification rate of the sine wave SWf2 > the amplification rate of the sine wave SWfl > the amplification rate of the sine wave SWfl.

[0107] The "amplification rate" may be the ratio of "the amplitude value of the output signal" to "the amplitude value of the input signal." In the case of the example presented in FIGS. 11 A and 11B, even when the sine waves having drive frequencies of fdll, fdl2, and fdl3 are input with the same amplitudes, the drive frequency at a resonance peak position has the strongest output amplitude. In such a case, it can be said that the drive frequency fdl2 is greatly amplified. The degree of amplification is referred to as an amplification rate.

[0108] When the input of the sine wave SWfl is "3," the output is "2." When the input of the sine wave SWf2 is "2," the output is "2." When the input of the sine wave SWf3 is "4," the output is " 1." To obtain the amplitude ratio of the desired output signal, the control device 11 executes feedback control of multiplying the amplitude value of an initial input signal by "the amplitude value of the desired output signal" / "the amplitude value of the detected detection signal" for each frequency component.

[0109] Amplitude value of input signal of sine wave SWfl = 3x(3 / 2) = 4.5 ... (6)Amplitude value of input signal of sine wave SWf2 = 2x(2 / 2) = 2 ... (7)Amplitude value of input signal of sine wave SWf3 = 4x(4 / l) = 16 ... (8)

[0110] Next, it is assumed that, when the drive signal having the amplitude ratio of 4.5:2: 16 is input to the first piezoelectric drive units 112a to 112d, a detection signal having an amplitude ratio =3.1 :2:3.9 is detected.The control device 11 uses the detected signal to determine the amplitude ratio of the drive signal that is the next input.

[0111] Amplitude value of input signal of sine wave SWfl = 4.5x(3 / 3.1) ... (9) Amplitude value of input signal of sine wave SWf2 = 2x(2 / 2) = 2 ... (10) Amplitude value of input signal of sine wave SWf3 = 16x(4 / 3.9) = 16 ... (11)

[0112] The control device 11 can correct the drive signal using Expressions (9) to (11) described above. The control device 11 can repeatedly execute such feedback control.

[0113] The control device 11 determines an input (drive signal) for finally obtaining a desired output (detection signal). The multiplication of "the amplitude value of the desired output signal" / "the amplitude value of the detected detection signal" has been discussed as the feedback control. For example, for the frequency component that is the sine wave SWfl, the amplitude value of the input signal at the first time is 4 times the amplitude value of the input signal at the zeroth time, and the change is larger than the change in the case of the inputFN202501267 signal of another frequency component (the sine wave SWfl or the sine wave SWf2). In this example, "zeroth time" represents the initial drive waveform in which the input amplitude of the sine wave SWfl is 4. Reference character "n" of the n-th time represents the number of times the drive waveform has been corrected. The zeroth time represents a state in which the correction of the drive waveform is not performed.

[0114] The control device 11 may aim to make the change gradual and make the change more likely to converge.The control device 11 may execute feedback control using Expression (12) below.Amplitude value = (1 / 2) + (l / 2)x ("amplitude value of desired output signal" / " amplitude value of detected detection signal") ... (12)

[0115] When Expression (12) described above is used, the change in the input of the frequency component that is the sine wave SWf3 from the zeroth time to the first time changes from 4 times in (a) to (f) of FIG. 12 to 2.5 times. Thus, (1 / 2) + (l / 2)x4 = 2.5 is established. While the input value of the sine wave SWf3 is increased by being multiplied by 2.5 and the amplitude value of the sine wave SWf3 as the output is also expected to approach the desired value, the change is more gradual.

[0116] The control device 11 may execute feedback control on the phase value in a manner similar to the case of the amplitude value described above.

[0117] While the ratio of the amplitude values varies between the input and the output due to the frequency response characteristics of the MEMS in the example described above, the control device 11 can execute similar feedback control even when, for example, an electric circuit has characteristics that vary depending on the frequency.

[0118] Even when the desired output signal has one frequency component, the control device 11 may execute feedback control of the amplitude or the phase. The optical scanning system including the drive device 13B and the control device 11 can execute Lissajous scanning. In such an optical scanning system, the control device 11 can execute feedback control of the amplitude and the phase.

[0119] [Correction Process for Input Waveform (Case 2)]Next, a correction process for an input waveform (case 2) will be described. FIG. 13 illustrates graphs presenting an example (case 2) of the transition of the amplitude of each frequency component in a correction process for an input waveform. FIG. 13(a) is a graph presenting an example of the input signal at the zeroth time, and the amplitude ratio of the frequency components of the input signal is 0:2:4. In order from the left, the ratio of the amplitude value of the sine wave SWfl, the ratio of the amplitude value of the sine waveFN202501267SWf2, and the ratio of the amplitude value of the sine wave SWf3 are presented. The straight line indicating the sine wave SWfl indicates that the amplitude value of the sine wave SWfl that is the frequency component is 0. FIG. 13(b) is a graph presenting an example of the output signal at the zeroth time, and the amplitude ratio of the frequency components of the output signal is 2:2:1.

[0120] FIG. 13(c) is a graph presenting an example of the input signal at the first time, and the amplitude ratio of the frequency components of the input signal is 2:2: 16. FIG. 13(d) is a graph presenting an example of the output signal at the first time, and the amplitude ratio of the frequency components of the output signal is 3.1 :2:3.9.

[0121] FIG. 13(e) is a graph presenting an example of the input signal at an n-th time. FIG. 13(f) is a graph presenting an example of the output signal at the n-th time, and the amplitude ratio of the frequency components of the output signal is 0:2:4.

[0122] It is desirable to obtain, as the output signal, the ratio as follows: the amplitude value of the sine wave SWfl : the amplitude value of the sine wave SWf2: the amplitude value of the sine wave SWf3 = 0:2:4. This case will be described.

[0123] First, the control device 11 receives the amplitude ratio = 0:2:4 of the frequency components obtained as the output signal. Here, it is assumed that the amplitude ratio = 2:2: 1 of the output signal is obtained due to the characteristics of the system including the drive device 13B. It will be discussed that, when 2 is obtained as the amplitude value of the sine wave SWfl of the output signal although the amplitude value of the sine wave SWfl that is the frequency component is 0, the amplitude value of the sine wave SWfl is cancelled. The amplitude value of the sine wave SWf2 and the amplitude value of the sine wave SWf3 are the same as those in the above-described correction process (case 1), and the description will be omitted.

[0124] Regarding the result of the input and output at the zeroth time, in order to set the amplitude value of the sine wave SWfl that is the frequency component of the output signal to 0, the amplitude value of the sine wave SWfl is input to the input. When the amplitude value of the sine wave SWfl of the input signal is turned to the output signal by the control device 11, and when the output signal and the amplitude value of the sine wave SWfl output at the zeroth time have the same amplitudes and opposite phases, the amplitude of the amplitude value of the sine wave SWfl of the output signal is 0.

[0125] To cause the output signal to have the same amplitude and the opposite phase, for example, the following means is conceivable. While the control device 11 receives the amplitude valueFN202501267 of the sine wave SWfl as the input for the input signal at the first time or later, the control device 11 uses a fixed value as the amplitude value and changes just the phase value.

[0126] In order to set the amplitude of the detection signal to 0 for a certain frequency component, a drive waveform that causes a component having the same amplitude and the opposite phase to be output may be input to the first piezoelectric drive units 112a to 112d. However, it is not easy to make the amplitude of the drive waveform before the correction and the amplitude of the drive waveform after the correction the same.

[0127] For example, when the detection signal includes a frequency component expressed by Expression (13) below, and when (Aout) in Expression (13) is to be set to 0, (Aout = 0) is not obtained even when Expression (14) below is input to the input signal.For example, when Expression (13) is simply substituted into Expression (14), Expression (15) below is obtained.Aoutxsin(27txf + out) - c(f)xAOutxsin(27txf + <FOut + ®(f)) ••• (15)

[0129] Since the above-described "amplification rate" depends on the frequency f, the input signal is multiplied by c(f), and the phase is shifted by (f). Thus, it is not easy to set the amplitude of a specific frequency component included in the detection signal to 0.

[0130] Instead of Expression (14) described above, Expression (16) below is input to the input signal, and (<bin) is changed.In this case, the output signal can be expressed using Expression (17) below.Aoutxsin(27txf + out) - c(f)xAOutxsin(27txf + <bOut + thin + ®(f)) ... (17)

[0132] At a certain m, Chin + <b(f) = 0 is established, and the amplitude of Expression (15) described above is minimized. Accordingly, the input signal having the opposite phase is input to the input signal before the correction.

[0133] At this time, when the amplitude values of the two sine waves SWfl of the output have opposite phases regardless of the amplitude values of the sine waves SWfl, the amplitude values of the sine waves SWfl of the detected output (detection signal) are minimized. The control device 11 fixes the phase value of the input signal at this time, and then changes the amplitude value to search for a value at which the amplitude value as the output of the sine waves SWfl is minimized.FN202501267

[0134] The control device 11 executes the above-described process to cancel the amplitude value of the sine wave SWfl. This process is effective when the amplitude value of the sine wave SWfl is not desired to be included in the output, or when the amplitude value of the sine wave SWfl is desired to be included but noise from the outside is desired to be canceled. The control device 11 can execute the above-described process to cancel the amplitude value of the sine wave SWfl and then superimpose an amplitude value to be used of the sine wave SWfl on the input. "The amplitude value is not desired to be included in the output" may represent "the amplitude value is not desired to be output."

[0135] For example, when a commercial power supply is used, a signal of 50 Hz is included in East Japan, but it is desirable to eliminate the influence of the signal of 50 Hz in the control device 11.

[0136] While a certain resonance frequency in the first piezoelectric drive units 112a to 112d serving as the MEMS is excited when the MEMS are driven, the oscillation is not used in the drive device 13B. Thus, it is desirable to eliminate a non-used signal in the control device 11.

[0137] There is also an application in which an input that changes with time is output as it is without using resonance as in vector scanning. In this case, when the input is subjected to the FFT, a waveform in which all frequency components are superimposed on each other is obtained, and a frequency component having the same frequency as the resonance frequency may be included in the input. At this time, for example, when it is intended to plot a straight line by vector scanning, just the component of the resonance frequency is amplified and output, and hence the straight line may undulate. In this case, in addition to a method of filtering an input, the correction method for the input waveform according to the present embodiment may be used.

[0138] [Processing Procedure of Feedback Control]Next, a processing procedure of feedback control executed by the control device 11 will be described. FIG. 14 is a flowchart presenting a processing procedure of feedback control executed by the control device 11.

[0139] The control device 11 appropriately sets a drive waveform (step Sil). Next, the control device 11 inputs the drive waveform to the first piezoelectric drive units (drive unit) 112a to 112d (step S12). Next, the control device 11 detects an output signal (step S13). The control device 11 receives a detection signal from the detective piezoelectric elements 160a to 160d. Accordingly, the control device 11 detects the output signal.

[0140] Next, the control device 11 executes FFT processing on the detection signal (step S14).FN202501267The control device 11 decomposes the detection signal into multiple frequency components. The detection signal includes a sine wave SWfl, a sine wave SWf2, and a sine wave SWf3 as the multiple frequency components.

[0141] Next, the control device 11 determines whether the amplitude value and the phase value of each frequency component of the detection signal meet a predefined desired set (step SI 5). The "desired set" may be a combination of ratios of the amplitude values of the multiple frequency components or a combination of ratios of the phase values of the multiple frequency components. The "desired set" is a combination of the amplitude and the phase of a drive signal for obtaining an ideal movement of the mirror 101.

[0142] For the movement of the mirror 101 serving as the MEMS mirror, there is a way of movement that is ideal for a user (designer), and this is basically expressed by superimposition of (multiple) sine waves. With information of the amplitude and the phase, the sine waves are uniquely determined. The set of the amplitude and the phase representing the ideal movement of the mirror 101 is referred to as a "desired set."

[0143] When the amplitude value and the phase value of each frequency component of the detection signal meet the predefined desired set (step SI 5; Yes), the control device 11 ends the processing. In the control device 11, for example, the output (displacement) of the first piezoelectric drive units 112a to 112d serving as the drive unit desirably satisfies the function form of Expression (1) described above in some cases. When Expression (1) described above is satisfied, the control device 11 determines that the amplitude value and the phase value of each frequency component of the detection signal meet the desired set, and ends the correction processing.

[0144] When the amplitude value and the phase value of each frequency component of the detection signal do not meet the predefined desired set (step SI 5; No), the control device 11 executes the processing of step SI 6.

[0145] In step SI 6, the control device 11 corrects the drive waveform based on an analysis result. For example, when the output of the first piezoelectric drive units 112a to 112d satisfies Expression (2) described above, the control device 11 can correct the amplitude value or the like of the input signal of the frequency component of fl so that, for example, the amplitude ratio of the frequency components is " 1 : 1."

[0146] After executing the processing in step SI 6, the control device 11 repeats the processing in step S12 to step S15.

[0147] FN202501267When the amplitude value and the phase value of each frequency component of the output signal meet the predefined desired set (step SI 5; Yes), the control device 11 ends the processing. The control device 11 outputs the finally determined drive signal to the first piezoelectric drive units 112a to 112d. The control device 11 repeatedly executes the feedback control presented in FIG. 14.

[0148] For the flow until the final determination on the drive signal input to the first piezoelectric drive units 112a to 112d, the control device 11 may set an initial input when desired. When an input that causes an output signal to be a desired signal has been obtained by performing the same flow at the time of previous driving, the control device 11 may reuse the input signal that is the final result.

[0149] [Operations and Advantageous Effects of Drive Device 13B According to Second Embodiment]The drive device 13B includes a mirror (movable portion) 101, first piezoelectric drive units (drive unit) 112a to 112d that drive the mirror 101, detective piezoelectric elements (detection unit) 160a to 160d that detect a displacement of the mirror 101, and a control device (drive controller) 11 that outputs a drive signal including multiple frequency components to control the first piezoelectric drive units 112a to 112d. Based on a specific frequency component decomposed from a detection signal output from the detective piezoelectric elements 160a to 160d, the control device 11 corrects a frequency component corresponding to the specific frequency component.

[0150] With such a drive device 13B, the output of the mirror 101 can be detected as the detection signal, and the detection signal can be decomposed into the multiple frequency component. Based on the decomposed specific frequency components, the drive device 13B can correct the frequency component corresponding to the specific frequency component. With this configuration, the mirror 101 can be accurately driven. The drive device 13B can reduce the distortion of a projected image.

[0151] In the drive device 13B, the control device 11 corrects an amplitude value of the frequency component corresponding to the specific frequency component based on an amplitude value of the specific frequency component.A drive device includes a movable portion (e.g., a mirror 101); a driver (the first drive units 110a and 110b); a detector (e.g., detective piezoelectric elements 160a, 160b, 160c, 160d); and a drive controller (e.g., a controller 30). The driver receives a drive signal including multiple first frequency components (e.g., SWfl, SWf2, SWf3 in FIG. 12(a)) and drives the movable portion based on the drive signal received by the driver. The detector detects a displacement of the movable portion and outputs a detection signal based on the displacement of the movable portion detected by the detector. The drive controller decomposes theFN202501267 detection signal output from the detector into multiple second frequency components (e.g., SWfl, SWf2, SWf3 in FIG. 12(b)); determines (SI 5) whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifies a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; corrects (SI 6) the amplitude value and the phase value of the multiple first frequency component to be matched with the amplitude value and the phase value of one of the target frequency components; and outputs, to the driver, the drive signal including the multiple second frequency components including the multiple first frequency components corrected, to control the driver.A driving method includes receiving a drive signal including multiple first frequency components (SWfl, SWf2, SWf3, FIG. 12(a)); decomposing a detection signal output from a detector into multiple second frequency components (SWfl, SWf2, SWfi, FIG. 12(b)); determining (SI 5) whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifying a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correcting (SI 6) the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and outputting, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver.A recording medium carrying computer readable codes which, when executed by a computer system, cause the computer system to carry out control processing of: decomposing a detection signal output from a detector into multiple second frequency components (SWfl, SWf2, SWfi, FIG. 12(b)); determining (SI 5) whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifying a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correcting (SI 6) the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and outputting, to the driver, the drive signal including the multiple first frequency corrected, to control the driver.

[0152] As a case where correction is not performed using the amplitude value, for example, there is proportional-integral-derivative (PID) control used for control of a robot or the like. Such PID control is effective when the input signal is decomposed into frequency components, and when there is one frequency component or when the change in the input signal with respect toFN202501267 time is gradual. However, when multiple high-speed sine waves are input as a drive signal to the first piezoelectric drive units 112a to 112d serving as the MEMS, the time scale of the PID control is too long, and hence it is not easy to control the first piezoelectric drive units 112a to 112d by the PID control.

[0153] When the PID control is used, the PID control corresponds to control of correcting all frequency components little by little, which is not desired.

[0154] The frequency components are independent of each other in many cases, and even when the amplitude of a certain frequency component is changed, the amplitudes of the other frequency components do not change much. As described above, it is easier to correct multiple independent parameters than to correct one parameter such as time in terms of reproducibility and controllability. The drive device 13B corrects the amplitude value of the frequency component corresponding to the specific frequency component, and hence can easily control the operations of the first piezoelectric drive units 112a to 112d. The drive device 13B can make the movement of the mirror 101 close to the ideal movement.

[0155] In the drive device 13B, the control device 11 can correct a phase value of the frequency component corresponding to the specific frequency component based on a phase value of the specific frequency component. The drive device 13B with this configuration corrects the phase value of the frequency component corresponding to the specific frequency component as an independent parameter to easily control the operations of the first piezoelectric drive units 112a to 112d. The drive device 13B can make the movement of the mirror 101 close to the ideal movement.

[0156] In the drive device 13B, when an amplitude value of the specific frequency component is cl (cl > 0) times a first target amplitude value, the control device 11 can multiply an amplitude value of the frequency component corresponding to the specific frequency component by (l / c2) (|1 - (l / c2)| < |1 - (l / cl)|, c2 > 0) to correct the amplitude value of the frequency component corresponding to the specific frequency component.The multiple first frequency components have a first amplitude, and the multiple second frequency components have a second amplitude. The drive control unit multiplies the first amplitude by (l / c2) to correct the first amplitude, when the second amplitude is cl (cl > 0) times a target amplitude, where |1 - (l / c2)| < |1 - (l / cl)|, and c2 > 0.

[0157] When the amplitude value is multiplied by ( 1 / c 1), the frequency component to be decomposed from the next detection signal is one times the target amplitude value (= intended value). However, when the change is more gradual than (1 / c 1 ) as described above, the amplitude value is multiplied by (l / c2). At this time, the value of c2 is desirably between 1 / cl and 1. When cl > 1, (1 / cl) < l / c2 is established. When cl < 1, (1 / cl) > (l / c2) > 1 isFN202501267 established. When these expressions are converted into a form applicable to both cl > 1 and are established.In the drive device 13B, when a phase value of the specific frequency component is + A l with respect to a first target phase value , the control device 11 may correct a phase value of the frequency component corresponding to the specific frequency component to 02 - A<I»2. In this case, 2n > A l > A<I»2 > 0 is established.The multiple first frequency components have a first phase, and the multiple second frequency components have a second phase. The drive control unit corrects the first phase to 2 - AO2, when the second phase is O + AO1 with respect to a first target phase value O, where 2TI > AO1 > AO2 > 0.

[0159] Reference character "O" represents a first target phase value. Expression "O + AO1" represents a phase of an output frequency component to be detected. Reference character "02" represents a phase of a frequency component in a drive waveform to be input to the drive unit by the control device 11. At this time, since the phase of the output frequency component to be detected is desirably set to the first target phase value O, the control device 11 sets the phase of the drive waveform to be input to the drive unit to 02 - AO1.

[0160] Since the change is also desired to be gradual, "AO2" is defined as | AO11 > |AO2|.

[0161] In the drive device 13B, when an amplitude value of the specific frequency component is a first amplitude value Al, a phase value of the specific frequency component is a first phase value Ol, and a first target amplitude value is 0, the control device 11 may set an amplitude value of the frequency component corresponding to the specific frequency component to the first amplitude value Al, and correct a phase value of the frequency component corresponding to the specific frequency component to - l. In order to set the above-described amplitude value to 0, the control device 11 causes a waveform having the same amplitude and the opposite phase to be included in the input signal. With this configuration, the drive device 13B can eliminate the frequency component that is not used for the output signal.The drive control unit sets the first amplitude of the corresponding one of the multiple first frequency component to a first amplitude value Al, and corrects a first phase of the corresponding one of the multiple first frequency component to a first phase value - l. In this case, the first amplitude value Al is a value of the second amplitude of the specific frequency component, and the first phase value l is a value of a second phase of the specific frequency component. Further, a first target amplitude value is 0.

[0162] In the drive device 13B, the control device 11 may output the drive signal satisfying Expression (18) below. f(t)xcos(coxt + ) ... (18)FN202501267In Expression (18) above, reference character "t" represents a time, reference characters "co" and "O" represent constants, and reference character "f(t)" represents a periodic function expressed by superimposition of a finite number of Fourier components. Reference character "co" may be denoted as "omega."The drive control unit outputs the drive signal satisfying Expression (l):f(t)*cos(co*t + ) where "t" represents a time, "co" and "O" represent constants, and "f(t)" represents a periodic function expressed by superimposition of a finite number of Fourier components in said Expression (1).

[0163] [Optical Scanning System 10]Next, an optical scanning system 10 to which the drive device 13 is applied will be described. FIG. 15 is a schematic diagram of an example of the optical scanning system 10. The optical scanning system 10 is a system that deflects light emitted from a light source device 12 to optically scan a target surface 15. The drive device 13 may be the drive device 13B according to the second embodiment. In the description of the optical scanning system 10, the description similar to that of the above-described embodiments may be omitted.

[0164] The optical scanning system 10 includes the control device 11, the light source device 12, and the drive device 13. The drive device 13 may include the control device 11 and the light source device 12.

[0165] For example, the control device 11 is an electronic circuit unit including a CPU and a FPGA. The drive device 13 includes the mirror 101. The mirror 101 has the reflecting surface 14. The drive device 13 is a MEMS device that drives the mirror 101.

[0166] The light source device 12 is, for example, a laser device that emits a laser beam. The target surface 15 is, for example, a screen.

[0167] The control device 11 generates control instructions for the light source device 12 and the drive device 13 based on acquired optical scanning information. The control device 11 outputs drive signals to the light source device 12 and the drive device 13 based on the control instructions. The light source device 12 emits light from a light source based on the received drive signal. The drive device 13 can rotate the reflecting surface 14 around the X-axis based on the received drive signal. The drive device 13 can rotate the reflecting surface 14 around the Y-axis based on the received drive signal. The drive device 13 may rotate the reflecting surface 14 around an axis extending in another direction.

[0168] With the rotation of the reflecting surface 14, the optical scanning system 10 can project the light reflected by the reflecting surface 14 onto the target surface 15 to perform optical scanning. The optical scanning system 10 can project any image onto the target surface 15.FN202501267

[0169] [Hardware Configuration of Optical Scanning System 10]Next, the hardware configuration of an example of the optical scanning system 10 will be described below. FIG. 16 is a diagram illustrating the hardware configuration of the example of the optical scanning system 10. The control device 11, the light source device 12, and the drive device 13 are electrically connected to each other. The control device 11 includes a CPU 20, a RAM 21, a ROM 22, a FPGA 23, an external I / F 24, a light-source driver 25, and a drive-device driver 26.

[0170] The CPU 20 is an arithmetic device that reads programs and data from storage devices, such as the ROM 22, into the RAM 21 and processes the programs and data to control and implement the functions of the entire control device 11. The RAM 21 is a volatile storage device that temporarily holds a program and data. The ROM 22 is a nonvolatile storage device that can store a program and data even when the power is switched off. The ROM 22 stores data and a processing program executed by the CPU 20 to control each function of the optical scanning system 10.

[0171] The FPGA 23 is a circuit that outputs proper control signals to the light-source driver 25 and the drive-device driver 26 in accordance with the processing performed by the CPU 20. For example, the external I / F 24 is an interface with respect to an external device or a network. The external device may be, for example, a host device such as a PC; or a storage device, such as a USB memory, a SD card, a CD, a DVD, a HDD, or a SSD. The network may be, for example, a CAN of a vehicle, a LAN, or the Internet. The external I / F 24 can have any configuration that can achieve connection to an external device or communication with an external device. The external I / F 24 may be provided for each external device.

[0172] The light-source driver 25 is an electric circuit that outputs a drive signal such as a drive voltage to the light source device 12 in accordance with the received control signal. The drive-device driver 26 is an electric circuit that outputs a drive signal such as a drive voltage to the drive device 13 in accordance with the received control signal.

[0173] In the control device 11, the CPU 20 acquires optical scanning information from an external device or a network through the external I / F 24. As far as the CPU 20 can acquire the optical scanning information, the optical scanning information may be stored in the ROM 22 or the FPGA 23 in the control device 11. Alternatively, a storage device such as an SSD may be additionally included in the control device 11, and the optical scanning information may be stored in the storage device.

[0174] The scanning information is information indicating how to perform optical scanning on the target surface 15. For example, the optical scanning information may be image data when anFN202501267 image is to be displayed by optical scanning. For example, the optical scanning information is writing data indicating the writing sequence and the writing locations when optical writing is performed by optical scanning. For example, the optical scanning information is irradiation data indicating the irradiation timing and the irradiation range of the light for object recognition when object recognition is performed by optical scanning.

[0175] The control device 11 enables the functional configuration described below by using instructions from the CPU 20 and the hardware configuration.

[0176] [Functional Configuration of Control Device 11]Next, the functional configuration of the control device 11 of the optical scanning system 10 will be described below. FIG. 17 is a block diagram illustrating the functional configuration of an example of the control device 11. The control device 11 includes a controller 30 and a drive-signal output unit 31. For example, the controller 30 is implemented by the CPU 20 or the FPGA 23. The controller 30 acquires optical scanning information from an external device, converts the optical scanning information into a control signal, and outputs the control signal to the drive-signal output unit 31. For example, the controller 30 acquires image data as the optical scanning information from an external device, generates a control signal from the image data through predetermined processing, and outputs the control signal to the drivesignal output unit 31. The drive-signal output unit 31 is implemented by, for example, the light-source driver 25 or the drive-device driver 26. The drive-signal output unit 31 outputs a drive signal to the light source device 12 or the drive device 13 based on the received control signal.

[0177] The drive signal is a signal for controlling the driving of the light source device 12 or the drive device 13. The drive signal to be output to the light source device 12 is, for example, a drive voltage that controls the irradiation timing and the irradiation intensity of the light source. The drive signal to be output to the drive device 13 is, for example, a drive voltage that controls the timing at which the reflecting surface 14 is moved and the movable range of the reflecting surface 14. The drive signal to be output to the drive device 13 may be the drive signal according to the first embodiment described above or the drive signal according to the second embodiment described above.

[0178] [Optical Scanning Process]Next, the process of optically scanning the target surface 15 performed by the optical scanning system 10 will be described below. FIG. 18 is a flowchart presenting an example of a processing procedure executed in the optical scanning system 10.

[0179] In step S21, the controller 30 acquires optical scanning information from, for example, an external device. In step S22, the controller 30 generates a control signal from the acquiredFN202501267 optical scanning information and outputs the control signal to the drive-signal output unit 31. In step S23, the drive-signal output unit 31 outputs drive signals to the light source device 12 and the first piezoelectric drive units 112a to 112d of the drive device 13 based on the received control signal. In step S24, the light source device 12 emits light based on the received drive signal. The first piezoelectric drive units 112a to 112d of the drive device 13 rotate the reflecting surface 14 based on the received drive signal. With the optical scanning system 10, light is deflected in any direction and optical scanning is performed by the driving of the light source device 12 and the drive device 13.

[0180] The optical scanning system 10 may separately include the control device 11 that controls the first piezoelectric drive units 112a to 112d of the drive device 13 and a control device that controls the light source device 12.

[0181] The optical scanning system 10 can reduce a decrease in resonance frequency that occurs when the mirror 101 serving as a movable portion is increased in size. The optical scanning system 10 can perform optical scanning with high accuracy.

[0182] [Head-up Display 500]Next, a head-up display (HUD) 500 will be described. FIG. 19 is a schematic diagram illustrating an example of a vehicle 400 with the HUD 500 mounted. The HUD 500 is mounted on the vehicle 400. The HUD 500 is an image projection apparatus that projects an image by optical scanning. The vehicle 400 is an example of a mobile object.

[0183] As illustrated in FIG. 26, the HUD 500 is disposed, for example, in the vicinity of a windshield 401 of the vehicle 400. Projection light L that is emitted from the HUD 500 is reflected by the windshield 401 and directed to an observer (or a driver 402) as a user. This allows the driver 402 to visually recognize, for example, an image projected by the HUD 500, as a virtual image.Alternatively, a combiner may be disposed on the inner wall surface of the windshield 401 so that the user can visually recognize a virtual image formed by the projection light that is reflected by the combiner.

[0184] FIG. 20 is a schematic diagram illustrating an example of the HUD 500. The HUD 500 includes laser sources 501R, 501G, and 50 IB. The laser source 501R emits a red laser beam. The laser source 501G emits a green laser beam. The laser source 501B emits a blue laser beam.

[0185] The HUD 500 includes an incident optical system. The incident optical system includes collimator lenses 502, 503, and 504, two dichroic mirrors 505 and 506, and a light intensity adjuster 507. The collimator lenses 502 to 504 are provided for the laser sources 501R, 501G,FN202501267 and 501B. The laser beams emitted from the laser sources 501R, 501G, and 501B are incident on the drive device 13 via the incident optical system. The laser beams incident on the drive device 13 are reflected by the reflecting surface 14. The laser beams are deflected by the drive device 13.

[0186] The HUD 500 includes a projection optical system. The projection optical system includes a free-form surface mirror 509, an intermediate screen 510, and a projection mirror 511. The laser beams deflected by the drive device 13 are projected onto the windshield 401 via the projection optical system. The HUD 500 may project laser beams onto a screen. The HUD 500 may include a light source unit 530 that includes an optical housing and is unitized. The optical housing houses, for example, the laser sources 501R, 501G, and 50 IB, the collimator lenses 502, 503, and 504, and the dichroic mirrors 505 and 506.

[0187] The HUD 500 can project an intermediate image displayed on the intermediate screen 510 onto the windshield 401. With the HUD 500, the driver 402 can visually recognize the intermediate image projected on the windshield 401 as a virtual image.

[0188] The laser beams of RGB colors emitted from the laser sources 501R, 501G, and 50 IB are collimated by the collimator lenses 502, 503, and 504 into approximately parallel beams, and are combined by the two dichroic mirrors 505 and 506. Each of the dichroic mirrors 505 and 506 is an example of a combiner. The light intensity of the combined laser beams is adjusted by the light intensity adjuster 507, and then two-dimensional scanning is performed by the drive device 13 with the laser beams. Projection light L subjected to two-dimensional scanning by the drive device 13 is reflected by the free-form surface mirror 509 to correct distortion, and is then focused on the intermediate screen 510. The intermediate screen 510 displays an intermediate image. The intermediate screen 510 includes a microlens array in which microlenses are two-dimensionally arranged. The intermediate screen 510 enlarges the incident projection light L in units of microlenses.

[0189] The drive device 13 causes the reflecting surface 14 to rotate (reciprocate) in two-axis directions. The drive device 13 performs two-dimensional scanning using the projection light L incident on the reflecting surface 14. The driving of the drive device 13 is controlled in synchronization with the emission timings of the laser sources 501R, 501G, and 501B.

[0190] The image projection apparatus can project an image by performing optical scanning by the drive device 13 including the reflecting surface 14. The image projection apparatus may be, for example, a projector that is placed on a desk or the like and projects an image on a display screen. The image projection apparatus may be a HUD that is mounted on an attachment member worn on the head or the like of the observer and that projects an image on aFN202501267 transflective screen included in the attachment member or projects an image on an eyeball as a screen.

[0191] The image projection apparatus is not limited to an image projection apparatus mounted on a vehicle or an attachment member. For example, the image projection apparatus may be mounted on a mobile object such as an aircraft, a ship, or a mobile robot. The image projection apparatus may be mounted on a non-mobile object such as a work robot that operates a drive object such as a manipulator without moving from the place.

[0192] The image projection apparatus including the drive device 13 can reduce a decrease in resonance frequency that occurs when the movable portion is increased in size, and can perform optical scanning with high accuracy. The image projection apparatus including the drive device 13 can increase the resolution of the trajectory of light near the center O of angle of view.

[0193] [Optical Writing Device 600]Next, an optical writing device 600 including the drive device 13 will be described. FIG. 21 is a schematic view illustrating an example of an image forming apparatus 610 with the optical writing device 600 mounted. The image forming apparatus 610 may be a laser printer 650. The laser printer 650 has a printer function using laser beams. The laser printer 650 includes the optical writing device 600. The optical writing device 600 optically scans a photoconductor drum serving as a target surface 15 with one or multiple laser beams. The optical writing device 600 performs optical writing on the photoconductor drum by optical scanning. The optical writing device 600 includes the drive device 13.

[0194] FIG. 22 is a schematic diagram illustrating an example of the optical writing device 600. In the optical writing device 600, a laser beam emitted from a light source device 12 such as a laser element passes through an image forming optical system 601 such as a collimator lens, and then is deflected in one axis direction or two axis directions by the drive device 13.

[0195] The optical writing device 600 includes a scanning optical system 602. The scanning optical system 602 includes a first lens 602a, a second lens 602b, and a reflecting mirror 602c. The laser beam deflected by the drive device 13 is emitted to the target surface 15 (for example, a photoconductor drum or photosensitive paper) via the scanning optical system 602. With this operation, the optical writing device 600 performs optical writing on the target surface 15. The scanning optical system 602 focuses the laser beam into a spot on the target surface 15. As described above, the control device 11 applies a drive signal to the drive units 110a to HOd of the drive device 13 to rotate the reflecting surface 14.

[0196] FN202501267As described above, the optical writing device 600 can be applied to the image forming apparatus 610 having a printer function using laser beams. The image forming apparatus 610 with the optical writing device 600 mounted may be a laser label device. The optical writing device 600 may be mounted on an image forming apparatus such as a laser label device that includes a scanning optical system that can perform optical scanning in two axis directions, deflects laser beams to perform optical scanning on a thermal medium, and performs printing by heating the thermal medium.

[0197] The drive device 13 including the reflecting surface 14 consumes less power for driving as compared to a rotary polygon mirror using a polygon mirror or the like. The optical writing device 600 including the drive device 13 can save power. The wind noise during oscillation of the drive device 13 is smaller than the wind noise during oscillation of the rotary polygon mirror. Thus, the optical writing device 600 including the drive device 13 can improve quietness. The installation space for the drive device 13 is significantly smaller than the installation space for the rotary polygon mirror. The amount of heat generated by the drive device 13 is significantly smaller than the amount of heat generated by the rotary polygon mirror. With the image forming apparatus including the optical writing device 600, the entire apparatus can be easily downsized.

[0198] As described above, when the drive device 13 according to the embodiment is applied to the optical writing device 600, a decrease in resonance frequency that occurs when the movable portion is increased in size can be reduced, and an optical writing device that can perform optical scanning with high accuracy can be provided. The optical writing device 600 including the drive device 13 can increase the resolution of the trajectory of light near the center O of angle of view.

[0199] [LiDAR Device 700]Next, a light detection and ranging or laser imaging, detection, and ranging (LiDAR) device 700 including the drive device 13 will be described. FIGS. 23 and 24 are schematic diagrams illustrating examples of a vehicle 701 with the LiDAR device 700 mounted. FIG. 25 is a schematic diagram of an example of the LiDAR device 700. The LiDAR device 700 is a distance measuring device that measures the distance to an object in a target direction. The distance measuring device is an example of an object recognition apparatus. The LiDAR device 700 includes the drive device 13. For example, the LiDAR device 700 is mounted on the vehicle 701 to perform optical scanning in a target direction and receive the light reflected from an object 702 that exists in the target direction. Accordingly, the LiDAR device 700 measures the distance to the object 702. The vehicle 701 is an example of a mobile object.

[0200] FIG. 25 is a schematic sectional diagram illustrating an example of the LiDAR device 700. As illustrated in FIG. 25, the LiDAR device 700 includes an incident optical system. TheFN202501267 incident optical system includes a collimator lens 703 and a plane mirror 704. The collimator lens 703 is an optical system that collimates divergent light into substantially parallel beams. The laser beam emitted from the light source device 12 passes through the incident optical system and is emitted for scanning in one axis direction or two axis directions by the drive device 13.

[0201] The LiDAR device 700 includes a projection optical system including a projection lens 705. The light reflected by the reflecting surface 14 of the drive device 13 is emitted to the object 702 in the area in the front via the projection lens 705. The control device 11 controls the driving of the light source device 12 and the drive device 13. The light reflected by the object 702 is detected by a photodetector 709. The reflected light is received by an imaging element 707 via a condenser lens 706 or the like serving as an incident light detection light-receiving optical system. The imaging element 707 outputs a detection signal to a signal processor 708. The signal processor 708 performs predetermined processing on the received detection signal, such as binarization or noise processing, and outputs the result to a distance measuring circuit 710.

[0202] The distance measuring circuit 710 recognizes whether the object 702 is present based on the time difference between when the light source device 12 emits laser beams and when the photodetector 709 receives the laser beams, or based on the phase difference for each pixel of the imaging element 707 that has received the laser beams. Additionally, the distance measuring circuit 710 calculates distance information indicating the distance to the object 702.

[0203] Since the drive device 13 including the reflecting surface 14 is less likely to be broken and is small in size as compared to a polygon mirror, a small radar device with high durability can be provided. Such a LiDAR device is attached to, for example, a vehicle, an aircraft, a ship, or a robot, and can recognize whether an obstacle is present and measure the distance to the obstacle by optically scanning a predetermined range.

[0204] The distance measuring device performs optical scanning by controlling the drive device 13 including the reflecting surface 14 with the control device 11, and receives reflected light with the photodetector to measure the distance to the object 702. The object recognition apparatus is not limited to the distance measuring device. Any object recognition apparatus may be used as long as the object recognition apparatus includes the drive device 13, performs optical scanning, and receives reflected light with a photodetector to detect the object 702.

[0205] The object recognition apparatus may be, for example, a biometric authentication device that calculates object information such as the shape from distance information obtained by optically scanning a hand or a face and recognizes an object by referring to a record. TheFN202501267 object recognition apparatus may be a security sensor that recognizes an intruding object by optical scanning in a target range. The object recognition apparatus may be a three- dimensional scanner that calculates and recognizes object information such as the shape from distance information obtained by optical scanning and outputs the object information as three- dimensional data.

[0206] Such a distance measuring device including the drive device 13 can reduce a decrease in resonance frequency that occurs when the movable portion is increased in size, and can perform optical scanning with high accuracy. The distance measuring device including the drive device 13 can increase the resolution of the trajectory of light near the center O of angle of view.

[0207] [Laser Headlamp 50]Next, a laser headlamp 50 including the drive device 13 will be described. FIG. 26 is a schematic diagram illustrating an example of the laser headlamp 50. The laser headlamp 50 may be a headlight of a vehicle. The laser headlamp 50 includes a light source device 12b, the drive device 13, a mirror 51, and a transparent plate 52. The laser headlamp 50 includes the control device 11 serving as a controller.

[0208] The light source device 12b is a light source that emits blue laser beams. The light emitted from the light source device 12b enters the drive device 13 and is reflected by the reflecting surface 14. The drive units 110a to HOd of the drive device 13 rotate the reflecting surface 14 based on a signal from the control device 11. The drive device 13 rotates the reflecting surface 14 to perform two-dimensional scanning with the laser beams in the XY directions.

[0209] The scanning light from the drive device 13 is reflected by the mirror 51 and enters the transparent plate 52. The transparent plate 52 has either its front or back surface coated with a yellow phosphor. The blue laser beams reflected by the mirror 51 turn into white light, which falls within the legally prescribed color range for headlights when passing through the yellow phosphor coating on the transparent plate 52. With this configuration, the area in front of the vehicle with the laser headlamp 50 mounted is illuminated with white light.

[0210] The scanning light from the drive device 13 is scattered in a predetermined manner when passing through the phosphor of the transparent plate 52.This reduces the glare on target objects illuminated in the area in front of the vehicle.

[0211] In the laser headlamp 50, the colors of the light source device 12b and the phosphor are not limited to blue and yellow, respectively. The laser headlamp 50 may include a light source device 12b that emits near ultraviolet rays. In the laser headlamp 50, the transparent plate 52 may be coated with a material obtained by uniformly mixing phosphors of blue, green, andFN202501267 red, which are three primary colors of light. The laser headlamp 50 having this configuration can convert light passing through the transparent plate 52 into white light, and can illuminate the area in front of the vehicle with the white light.

[0212] Such a laser headlamp 50 including the drive device 13 can reduce a decrease in resonance frequency that occurs when the movable portion is increased in size, and can perform optical scanning with high accuracy. The laser headlamp 50 including the drive device 13 can increase the resolution of the trajectory of light near the center O of angle of view.

[0213] [Head-mounted Display 60]Next, a head-mounted display (HMD) 60 including the drive device 13 will be described. FIG. 27 is a perspective view illustrating an example of the HMD 60. FIG. 28 is a schematic sectional diagram partially illustrating the HMD 60. The HMD 60 is a head-mounted display that can be worn on the head of a person. The HMD 60 may have, for example, a shape similar to the shape of eyeglasses. Hereinafter, the head-mounted display may be abbreviated as a HMD.

[0214] The HMD 60 includes a front 60a and a temple 60b provided substantially symmetrically on each of the left and right sides. The front 60a includes, for example, a light guide plate 61. The temple 60b can incorporate an optical system, the control device 11, and other components.

[0215] FIG. 28 illustrates a portion for the left eye of the HMD 60. The portion for the right eye of the HMD 60 has the same configuration as the portion for the left eye. The HMD 60 includes a light source unit 530, a light intensity adjuster 507, the drive device 13, the light guide plate 61, and a semi-reflective mirror 62.The drive device 13 may include the control device 11 as a controller.

[0216] As described above, the light source unit 530 is unitized by the optical housing. The light source unit 530 may be the light source device 12. As illustrated in FIG. 20, the light source unit 530 houses the laser sources 501R, 501G, and 501B, the collimator lenses 502, 503, and 504, and the dichroic mirrors 505 and 506. In the light source unit 530, the laser beams of three colors emitted from the laser sources 501R, 501G, and 50 IB are combined by the dichroic mirrors 505 and 506. The light source unit 530 emits combined parallel beams.

[0217] The intensity of the light emitted from the light source unit 530 is adjusted by the light intensity adjuster 507, and then the light is incident on the drive device 13. The drive device 13 causes the reflecting surface 14 to rotate based on a drive signal input from the control device 11. The drive device 13 emits the light incident from the light source unit 530 for two- dimensional scanning. The control device 11 drives and controls the first piezoelectric driveFN202501267 units 112a to 112d of the drive device 13 in synchronization with the emission timings of the laser sources 501R, 501G, and 50 IB. The HMD 60 forms a color image with scanning light.

[0218] As illustrated in FIG. 28, the scanning light from the drive device 13 is incident on the light guide plate 61. The light guide plate 61 reflects the scanning light off its inner wall, guiding the scanning light to the semi -reflective mirror 62. The light guide plate 61 is formed from a material such as a resin having transparency at the wavelength of the scanning light.

[0219] The semi-reflective mirror 62 reflects the light from the light guide plate 61 to the rear side of the HMD 60, directing the light toward the eye of a wearer 63 of the HMD 60. The semi- reflective mirror 62 has, for example, a free-form surface shape. The image formed by the scanning light is reflected by the semi-reflective mirror 62 and projected onto the retina of the wearer 63. The HMD 60 projects the image of the scanning light onto the retina of the wearer 63 due to the reflection from the semi-reflective mirror 62 and the effect of the crystalline lens of the eyeball. Moreover, in the HMD 60, due to the reflection from the semi -reflective mirror 62, spatial distortion of the image is corrected. The wearer 63 can observe an image formed by the light that is scanned in the XY directions.

[0220] The HMD 60 including the semi -reflective mirror 62 allows the wearer 63 to observe an image in which an image formed by the external light is superimposed on an image formed by scanning light. The HMD 60 may include a mirror instead of the semi-reflective mirror 62. The HMD 60 of this configuration shuts out external light, allowing the wearer 63 to observe just the image formed by the scanning light.

[0221] Applying the drive device 13 according to the embodiment to the head-mounted display as described above can provide a head-mounted display that can reduce a decrease in resonance frequency that occurs when the movable portion is increased in size and that can perform optical scanning with high accuracy.

[0222] Such a HMD 60 including the drive device 13 can reduce a decrease in resonance frequency that occurs when the movable portion is increased in size and perform optical scanning with high accuracy. The HMD 60 including the drive device 13 can increase the resolution of the trajectory of light near the center O of angle of view.

[0223] [Eyeball-tilt Position Detector (Pupil or Cornea position detection apparatus 80)]Next, an eyeball-tilt position detector including the drive device 13 will be described. The eyeball-tilt position detector is a pupil or cornea position detection apparatus 80 that detects the position of a pupil or a cornea. FIG. 29 is a schematic diagram illustrating the configuration of an example of the pupil or cornea position detection apparatus 80.

[0224] FN202501267The "eyeball-tilt position" according to an embodiment of the present disclosure refers to the position of the pupil or cornea of the eyeball, or the user's eye-gaze direction. In the following description, the "eyeball-tilt position" is referred to as the position of the pupil or cornea, and the "eyeball-tilt position detector" is referred to as the "pupil or cornea position detection apparatus." The pupil or cornea position detection apparatus described below is synonymous with an eye-gaze direction tracking device (or an eye tracking device) that detects or tracks the user's gaze direction continuously or at set time intervals.

[0225] The pupil or cornea position detection apparatus 80 illustrated in FIG. 29 includes a light source 82, a first optical deflector 83, the drive device 13, a second optical deflector 85, and a light receiver 86. The light source 82 may be the light source device 12. The pupil or cornea position detection apparatus 80 may include the control device 11.

[0226] The light source 82 includes, for example, laser sources 82r, 82g, and 82b and an infrared laser source 82ir. The laser sources 82r, 82g, and 82b emit a red laser beam, a green laser beam, and a blue laser beam, respectively. The infrared laser source 82ir emits an infrared laser beam. The laser sources 82r, 82g, and 82b may be any one of them or a combination of two of them. The laser sources 82r, 82g, and 82b emit light for rendering an image by the drive device 13.

[0227] The infrared laser source 82ir emits light for detecting the position of the pupil or cornea. The light for detecting the position of the pupil or cornea is not limited to infrared rays and may be visible light. The light for detecting the position of the pupil or cornea is preferably invisible light from the viewpoint of improving the visibility of the rendered image.

[0228] The first optical deflector 83 is, for example, a dichroic mirror, and deflects the light emitted from the light source 82 toward the reflecting surface 14 of the drive device 13 while combining the light. The pupil or cornea position detection apparatus 80 may include multiple first optical deflectors 83-1, 83-2, 83-3, 83-4, and 83-5 in accordance with the number of the laser sources 82r, 82g, and 82b and the infrared laser source 82ir. The first optical deflector 83 includes multiple first optical deflectors 83-1, 83-2, 83-3, 83-4, and 83-5. The multiple first optical deflectors 83-1, 83-2, 83-3, 83-4, and 83-5 deflect the laser beams while combining the laser beams.

[0229] The drive device 13 includes the reflecting surface 14 and emits the light deflected by the first optical deflector 83 toward the second optical deflector 85 for scanning in two-dimensional directions. At this time, the drive device 13 emits the light deflected by the first optical deflector 83 for scanning by, for example, raster scanning to form an image. The drive device 13 can perform scanning with the light deflected by the first optical deflector 83 by spiral scanning.FN202501267

[0230] The second optical deflector 85 is, for example, a holographic optical element, and deflects light LI emitted by the drive device 13 toward an eyeball 87 of a user. At least a part of light L2 deflected by the second optical deflector 85 impinges on the eyeball 87 of the user as display image light. In some embodiments, the second optical deflector 85 may include multiple optical deflection elements. For example, multiple types of optical deflection elements are used to reflect a specific laser beam of the laser beams emitted from the light source 82, respectively. In other words, different reflecting surfaces of the optical deflection elements correspond to the laser beams emitted from the light source 82. As a specific example, there is a configuration in which optical deflection elements that reflect the laser beams emitted by the laser sources 82r, 82g, and 82b and an optical deflection element that reflects the laser beam emitted by the infrared laser source 82ir are stacked in order of closeness to the eyeball 87.

[0231] The light receiver 86 receives light L3 reflected by the eyeball 87 of the user from the light L2 deflected by the second optical deflector 85 and outputs a detection signal SD corresponding to the received light. The light receiver 86 is, for example, an imaging element that can detect infrared rays. In some embodiments, multiple light receivers 86 may be placed at positions to detect light (i.e., the light L3) reflected by the eyeball 87 of the user. The intensity of the light received by the light receiver 86 changes with the position of the eyeball (e.g., the pupil or the cornea), that is, with the eye-gaze direction. Given the above, the pupil or cornea position detection apparatus 80 according to an embodiment of the present disclosure detects or estimates the position of the pupil or cornea based on the intensity of the light received by the light receiver 86. In some embodiments, the light receiver 86 may capture an image of the eyeball 87 irradiated with the light L2 deflected by the second optical deflector 85.In this configuration, the pupil or cornea position detection apparatus 80 detects or estimates the eyeball-tilt position based on the position of the pupil or cornea within the captured image (i.e., the detection signal SD) and the point on the eyeball 87 at which the light L2 deflected by the second optical deflector 85 reflects off.

[0232] As described above, the pupil or cornea position detection apparatus 80 according to the present embodiment can detect the position of the pupil or cornea while forming an image by the drive device 13. The drive device 13 having a configuration that can perform scanning with light more efficiently can provide image formation and detection of the position of the pupil or cornea with lower power. Furthermore, the drive device 13 can achieve the abovedescribed advantageous effect without changing the area to mount the drive device 13 on the pupil or cornea position detection apparatus 80, as compared to the configuration of the related art. With this configuration, the pupil or cornea position detection apparatus 80 is not increased in size.

[0233] FN202501267The pupil or cornea position detection apparatus 80 may be mounted on a HMD, for example, as an eye-gaze direction tracking (eye tracking) device to detect or track the eye-gaze direction of the user. In this configuration, for example, by lowering the resolution of images displayed in areas other than the area near the eye-gaze direction of the user (i.e., foveated rendering), a higher speed of image processing can be achieved than when displaying high- resolution images across the entire area.

[0234] FIG. 30 is a schematic diagram illustrating the configuration of an example of a pupil or cornea position detection apparatus 80. As illustrated in FIG. 30, the pupil or cornea position detection apparatus 80 includes a light source 82, first optical deflectors 83-1 to 83-4, a lens 92, a lens 93, a mirror 101, a mirror 101B, a second optical deflector 85, a light receiver 86, and the control device 11. The mirror 101 may be, for example, a scanning mirror. The mirror 10 IB may be a deflection mirror.

[0235] The lens 92 is an optical system that converts the light emitted from the light source 82 into substantially parallel beams. The lens 93 is an optical system that shapes the light, which has been converted into the substantially parallel beams by the lens 92, into a desired laser beam profile. In the present embodiment, both the lens 92 and the lens 93 are used. However, in some embodiments, the lens 92 and the lens 93 are not used.

[0236] The light formed by the lens 92 and the lens 93 is incident on the mirror (drive device 13) 101 serving as a scanning mirror. The mirror 101 performs scanning with incident light to form image light. The formed image light is incident on the mirror 10 IB serving as a deflection mirror and is reflected in a direction toward the second optical deflector 85. While the mirror 10 IB corresponds to the first optical deflector 83-5 described with reference to FIG. 29, the mirror 10 IB preferably has a configuration including the drive device 13 to perform scanning with light. With the configuration in which the mirror 10 IB serving as the deflection mirror can perform optical scanning, an image can be projected in a wider range.

[0237] While the mirror 101B serving as the deflection mirror is located between the mirror 101 serving as the scanning mirror and the second optical deflector 85 in the above-described example, the configuration of the pupil or cornea position detection apparatus 80 is not limited to the above-described configuration. In the pupil or cornea position detection apparatus 80, the mirror 101 serving as the scanning mirror may be located between the mirror 10 IB serving as the deflection mirror and the second optical deflector 85, and the light reflected by the mirror 10 IB may be emitted for scanning in two-axis directions by the mirror 101 and made incident on the second optical deflector 85.

[0238] The control device 11 detects the position of the pupil or cornea of the user based on the detection signal SD output by the light receiver 86 and acquires information indicating theFN202501267 eye-gaze direction. To form an image to be projected onto a retina 65, the control device 11 supplies a formation drive signal SLI to the light source 82 to control the emission and intensity of the light from the light source 82, and supplies a scanning drive signal Ss to the mirror 101 to drive the mirror 101.When the mirror 10 IB can perform optical scanning, the control device 11 supplies a deflection drive signal ST to the mirror 101B to drive the mirror 101B in order to control the position at which an image is projected in accordance with the acquired eye-gaze information.

[0239] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to such specific embodiments, and various modifications and changes can be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims.

[0240] In the above-described embodiments, the movable portion includes the reflecting surface. However, no limitation is intended thereby, and the movable portion may include another optical element such as a diffraction grating, a photodiode, a heater (for example, a heater using silicon nitride (SiN)), and a light source (for example, a surface-emitting laser), or may include both the reflecting surface and another optical element.

[0241] [Processing Circuit]The functions of the embodiments described above can be achieved by one or multiple processing circuits or circuitry. As used herein, the term "processing circuit or circuitry" includes processors programmed to implement each function by software, such as a processor implemented by an electronic circuit, and devices designed to implement the functions described above, such as an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), and existing circuit modules. The "processor" includes various arithmetic devices such as a CPU and a graphics processing unit (GPU). The processor reads various programs into the memory and executes the programs.

[0242] A description is given below of several aspects of the present disclosure.

[0243] According to Aspect 1, a drive device includes a movable portion; a drive unit that drives the movable portion; a detection unit that detects a displacement of the movable portion; and a drive controller that outputs a drive signal including multiple frequency components to control the drive unit. The drive controller corrects a frequency component of the multiple frequency components corresponding to a specific frequency component decomposed from a detection signal output from the detection unit, based on the specific frequency component. According to Aspect 2, in the drive device of Aspect 1, the drive controller corrects an amplitude of the frequency component corresponding to the specific frequency component based on an amplitude of the specific frequency component.FN202501267According to Aspect 3, in the drive device of Aspect 1 or Aspect 2, the drive controller corrects a phase of the frequency component corresponding to the specific frequency component based on a phase of the specific frequency component.According to Aspect 4, in the drive device of Aspect 2, the drive controller, when an amplitude value of the specific frequency component is cl (cl > 0) times a first target amplitude value, multiplies an amplitude value of the frequency component corresponding to the specific frequency component by c2 (cl > c2 > 1) to correct the amplitude value of the frequency component corresponding to the specific frequency component.According to Aspect 5, in the drive device of Aspect 3, the drive controller, when a phase value of the specific frequency component is <E> + A 1 with respect to a first target phase value <b, corrects a phase value of the frequency component corresponding to the specific frequency component to 2 - A 2, and 2it > A l > A 2 > 0 is established.According to Aspect 6, in the drive device of Aspect 2, the drive controller, when an amplitude value of the specific frequency component is a first amplitude value Al, a phase value of the specific frequency component is a first phase value l, and a first target amplitude value is 0, sets an amplitude value of the frequency component corresponding to the specific frequency component to the first amplitude value Al, and corrects a phase value of the frequency component corresponding to the specific frequency component to — 1. According to Aspect 7, in the drive device of Aspect 1, the drive controller outputs the drive signal satisfying Expression (1) below, f(t)xcos(coxt + <!>) ... (1), where "t" represents a time, "co" and "O" represent constants, and "f(t)" represents a periodic function expressed by superimposition of a finite number of Fourier components in said Expression (1).According to Aspect 8, a projection apparatus includes an optical scanning system including the drive device of Aspect 1 or Aspect 2.According to Aspect 9, a mobile object includes the projection apparatus of Aspect 8. According to Aspect 10, a head-mounted display includes the drive device of Aspect 1 or Aspect 2.According to Aspect 11, a head-up display includes the drive device of Aspect 1 or Aspect 2. According to Aspect 12, a laser headlamp includes the drive device of Aspect 1 or Aspect 2. According to Aspect 13, an object recognition apparatus includes the drive device of Aspect 1 or Aspect 2.According to Aspect 14, a pupil or cornea position detection apparatus includes the drive device of Aspect 1 or Aspect 2.According to Aspect 15, a driving method of outputting a drive signal including multiple frequency components to a drive unit that drives a movable portion to drive the drive unit includes detecting a displacement of the movable portion with a detection unit and outputting a detection signal relating to the displacement of the movable portion; and correcting a frequency component of the multiple frequency components corresponding to a specificFN202501267 frequency component decomposed from the detection signal, based on the specific frequency component.According to Aspect 16, a program that causes a computer system to carry out control processing of outputting a drive signal including multiple frequency components to a drive unit that drives a movable portion to cause the drive unit to be driven. The control processing includes receiving a detection signal relating to a displacement of the movable portion, and correcting a frequency component of the multiple frequency components corresponding to a specific frequency component decomposed from the detection signal, based on the specific frequency component.

[0244] The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.

[0245] The present invention can be implemented in any convenient form, for example using dedicated hardware, or a mixture of dedicated hardware and software. The present invention may be implemented as computer software implemented by one or more networked processing apparatuses. The processing apparatuses include any suitably programmed apparatuses such as a general purpose computer, a personal digital assistant, a Wireless Application Protocol (WAP) or third-generation (3G)-compliant mobile telephone, and so on. Since the present invention can be implemented as software, each and every aspect of the present invention thus encompasses computer software implementable on a programmable device. The computer software can be provided to the programmable device using any conventional carrier medium (carrier means). The carrier medium includes a transient carrier medium such as an electrical, optical, microwave, acoustic or radio frequency signal carrying the computer code. An example of such a transient medium is a Transmission Control Protocol / Intemet Protocol (TCP / IP) signal carrying computer code over an IP network, such as the Internet. The carrier medium may also include a storage medium for storing processor readable code such as a floppy disk, a hard disk, a compact disc read-only memory (CD- ROM), a magnetic tape device, or a solid state memory device.

[0246] The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, application- specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and / or combinations thereof which are configured or programmed, using one or more programs stored in one or more memories, to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors andFN202501267 other circuitry therein. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein which is programmed or configured to carry out the recited functionality.There is a memory that stores a computer program which includes computer instructions. These computer instructions provide the logic and routines that enable the hardware (e.g., processing circuitry or circuitry) to perform the method disclosed herein. This computer program can be implemented in known formats as a computer-readable storage medium, a computer program product, a memory device, a record medium such as a CD-ROM or DVD, and / or the memory of an FPGA or ASIC.

[0247] This patent application is based on and claims priority to Japanese Patent Application No. 2024-211579, filed on December 4, 2024, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Reference Signs List]

[0248] 10 Optical scanning system11 Control device (drive controller)13, 13B Drive device14 Reflecting surface30 Controller (drive controller)50 Laser headlamp60 Head-mounted display101 Mirror (movable portion)110a, 110b, 110c, HOd First drive unit (driver)112a, 112b, 112c, 112d First piezoelectric drive unit160a, 160b, 160c, 160d Detective piezoelectric element (detector)400 Vehicle (mobile object)500 Head-up display (projection apparatus)600 Optical writing device610 Image forming apparatus700 LiDAR device (object recognition apparatus)

Claims

FN202501267[CLAIMS]1. A drive device comprising: a movable portion; a driver configured to: receive a drive signal including multiple first frequency components; and drive the movable portion based on the drive signal received by the driver; a detector configured to: detect a displacement of the movable portion; and output a detection signal based on the displacement of the movable portion detected by the detector; and a drive controller configured to: decompose the detection signal output from the detector into multiple second frequency components; determine whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identify a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correct the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and output, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver.

2. The drive device according to claim 1, wherein the multiple first frequency components have a first amplitude, the multiple second frequency components have a second amplitude, and the drive control unit is further configured to: multiply the first amplitude by (l / c2) to correct the first amplitude, when the second amplitude is cl (cl > 0) times a target amplitude:

3. The drive device according to claim 1, wherein the multiple first frequency components have a first phase, the multiple second frequency components have a second phase, and the drive control unit is further configured to: correct the first phase to 2 - A 2, when the second phase is + A<I» I with respect to a first target phase value ,FN202501267 where 2n > A 1 > A2 > 0.

4. The drive device according to claim 2, wherein the drive control unit is configured to: set the first amplitude of the corresponding one of the multiple first frequency component to a first amplitude value Al, and correct a first phase of the corresponding one of the multiple first frequency component to a first phase value — 1 , where the first amplitude value Al is a value of the second amplitude of the specific frequency component, the first phase value <bl is a value of a second phase of the specific frequency component, and a first target amplitude value is 0.

5. The drive device according to claim 1, wherein the drive control unit is configured to output the drive signal satisfying Expression (1) below, f(t)xcos(coxt + <!>) ... (1), where"t" represents a time,"co" and "O" represent constants, and"f(t)" represents a periodic function expressed by superimposition of a finite number of Fourier components in said Expression (1).

6. A driving method comprising: receiving a drive signal including multiple first frequency components; decomposing a detection signal output from a detector into multiple second frequency components; determining whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifying a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correcting the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and outputting, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver.FN2025012677. A recording medium carrying computer readable codes which, when executed by a computer system, cause the computer system to carry out control processing of: decomposing a detection signal output from a detector into multiple second frequency components; determining whether an amplitude value and a phase value of each of the multiple second frequency components of the detection signal match an amplitude value and a phase value of target frequency components; identifying a specific frequency component, in the multiple second frequency components, having the amplitude value and the phase value that do not match the amplitude value and the phase value of the target frequency components; correcting the amplitude value and the phase value of the multiple first frequency components to be matched with the amplitude value and the phase value of one of the target frequency components; and outputting, to the driver, the drive signal including the multiple first frequency components corrected, to control the driver.

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