JP2023097199A - Mirror device for scanning - Google Patents

Abstract

To provide a mirror device for scanning that simplifies device configuration and reduces influence of heat generated during operation.SOLUTION: A mirror device for scanning, includes: a mirror part in which a mirror surface is formed; a first mirror support part which supports the mirror part; a first axis which rotatably supports the first mirror support part in a position dividing a first region having a first mass and a second region having a second mass larger than the first mass; and a first vibration source which generates a first wave with same frequency as a first resonance frequency of the first region, resonates the first region, and vibrates the first mirror support part around the first axis.SELECTED DRAWING: Figure 1

Description

1. Field of the Invention The present invention relates to a scanning mirror device that has been miniaturized using semiconductor manufacturing technology.

A two-dimensional scanning MEMS (Micro Electro Mechanical Systems) mirror device (planar actuator) for scanning laser light emitted from a laser light source and projecting a two-dimensional image is known (see, for example, Patent Document 1). ). The mirror device described in Patent Document 1 includes, for example, a mirror that reflects laser light, a first frame that is provided around the mirror and supports the mirror rotatably about a first rotation axis, and a a second frame that rotatably supports the first frame by a second rotating shaft that is provided in a direction orthogonal to the first rotating shaft.

This mirror device includes a first magnet that generates at least one first magnetic field in the direction along the first rotation axis, and a second magnet that generates at least one second magnetic field in the direction along the second rotation axis. with a magnet. The mirror arrangement also comprises at least one first electrode through which current flows in the mirror in a direction perpendicular to the second magnetic field. The mirror arrangement also comprises at least one second electrode through which current flows in the first frame in a direction perpendicular to the first magnetic field.

This mirror device generates a Lorentz force based on the alternating current flowing through the first electrode, vibrates the mirror around the first rotation axis based on resonance, and generates the Lorentz force based on the alternating current flowing through the second electrode. The first frame and the mirror are vibrated around the second rotation axis based on resonance, and the laser beam reflected on the mirror can be scanned.

According to the mirror device described in Patent Document 1, it is necessary to arrange a total of two pairs (four) of permanent magnets around the MEMS mirror element in order to generate a magnetic field. prevented it from becoming In order to reduce the size and cost of the device, it is desirable to reduce the number of permanent magnets which are large and costly compared to the MEMS elements. In addition to the configuration described above, Patent Literature 1 describes another mirror device in which a pair of magnets are arranged on a diagonal line of a mirror or frame to generate magnetic field components in two axial directions.

Japanese Patent Application Laid-Open No. 2009-89501

However, according to the other mirror device described in Patent Document 1, since one magnetic field is orthogonally resolved to obtain magnetic forces in two directions, the magnetic fields in each axial direction become weak, and as a result, the magnetic field is proportional to the magnetic field. The problem is that the electromagnetic force is also weakened, limiting the rotation angle of the mirror and degrading the performance. Further, according to another mirror device described in Patent Document 1, the mirror needs to be arranged at an angle of 45 degrees with respect to the direction of the magnetic field.

Furthermore, according to the technique described in Patent Document 1, it is necessary to provide a coil structure for electromagnetically generating vibrations in the movable portion of the mirror and the first frame. Then, according to the technique described in Patent Document 1, the mirror and the movable portion of the first frame are connected to the second frame only at the rotating shaft portion and are separated from the second frame. Therefore, the technique described in Patent Document 1 has a problem that the wiring provided in the mirror and the first frame is complicated.

Furthermore, in the technique described in Patent Document 1, the movable part including the mirror and the first frame is thermally separated from the second frame, and the electrodes provided on the mirror and the first frame When energized, the movable part is heated, the resonance frequency is changed, the mirror surface is bent, and the operation of the device becomes unstable.

In the technique described in Patent Document 1, when attempting to rotate the mirror in the direction of the first axis and the direction of the second axis based on one driving coil of the movable part, an external force is applied to the movable part. Two magnetic fields are required, and two frequency signals must be electrically added and synthesized. Therefore, according to the technique described in Patent Document 1, there is a problem that the number of driving circuits for driving the driving coils is increased, and the maximum current is limited by the adding circuit.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a scanning mirror device capable of simplifying the device configuration and reducing the influence of heat generated during driving.

To achieve the above object, the present invention provides a mirror portion having a mirror surface formed thereon, a first mirror support portion for supporting the mirror portion, and a first mirror support portion having a first mass. a first shaft rotatably supported at a position dividing a region and a second region having a second mass having a mass larger than the first mass; and a first vibration source that generates a first wave of a number to resonate the first region and vibrate the first mirror support portion around the first axis.

According to the present invention, the device configuration can be simplified and the influence of heat generated during driving can be reduced.

It is a figure which shows the structure of the mirror apparatus for scanning based on embodiment of this invention. FIG. 2 is a cross-sectional view of a schematic configuration of a scanning mirror device viewed in a first axis direction; FIG. 3 is a cross-sectional view of a schematic configuration of a scanning mirror device viewed in a second axis direction; It is a figure which shows the state of the mirror part which vibrates around a 1st axis|shaft based on the resonance of a 1st frequency. It is a figure which shows the state of the mirror part which vibrates around a 1st axis|shaft based on resonance of a 2nd frequency. It is a figure which shows the state of the mirror part which vibrates around the 2nd axis|shaft based on the resonance of a 3rd frequency. It is a figure which shows the state of the mirror part which vibrates along a Z-axis based on the resonance of 4th frequency. It is a figure which shows the measurement point in the performance test of the mirror apparatus for scanning. FIG. 4 is a diagram showing results of a performance test of the scanning mirror device;

An embodiment of a scanning mirror device according to the present invention will be described below with reference to the drawings. In the following description, XYZ coordinates are set. Each axial direction is appropriately referred to as one side, the other side, or the like. The set coordinates are relative and are not limited to this. The scanning mirror device is, for example, a two-dimensional scanning mirror element that has been miniaturized by MEMS using semiconductor manufacturing technology. The scanning mirror device is configured in an electrically driven electromagnetic actuator. Scanning mirror devices are used, for example, as sources of electromagnetic waves including light from small projectors and LiDAR (Light Detection and Ranging).

As shown in FIG. 1, the scanning mirror device 1 reflects electromagnetic waves irradiated from the wave source section 40, is driven by alternating current input from the power supply section 20, and two-dimensionally scans the reflected electromagnetic waves. is configured as The wave source section 40 and the power supply section 20 are controlled by the control device 10 as described later.

The scanning mirror device 1 is formed by one substrate 2 . The substrate 2 is formed with a mirror surface M1 that reflects electromagnetic waves such as laser light and radar waves emitted from the wave source 40, for example. A mirror surface M1 is formed on the mirror portion M. As shown in FIG. A first mirror supporting portion 3 for supporting the mirror portion M is formed on the substrate 2 . The first mirror support portion 3 is formed in a rectangular plate-like body, for example. A first groove H<b>1 separating the first mirror support portion 3 and the substrate 2 is formed around the first mirror support portion 3 . The first mirror support portion 3 is arranged, for example, so that its longitudinal direction is formed along the X-axis and its short-side direction is along the Y-axis direction. The first mirror support part 3 is rotatably supported with respect to the substrate 2 by, for example, a first axis S1 along the Y-axis direction in the figure.

The first shaft S1 is formed in a torsion bar that elastically deforms in the twisting direction. The first axis S<b>1 is formed by leaving a bar shape with a predetermined width when forming the first groove H<b>1 in the substrate 2 . The first axis S1 extends along the Y-axis direction of the first mirror support portion 3 and a first torsion bar S1A that supports the first side surface 3P on one axial side of the first mirror support portion 3 along the Y-axis direction. and a second torsion bar S1B that supports the second side surface 3Q on the other side in the axial direction. The first torsion bar S1A connects the first side surface 3P and the substrate 2 (the first diaphragm described later). The second torsion bar S1B connects the second side surface 3Q and the substrate 2 (second vibration plate, which will be described later).

The first axis S1 is arranged at a position dividing the first mirror supporter 3 into a first area 3A and a second area 3B. The first region 3A is segmented to have a first mass. The first region 3A is formed in a first plate-like body C having a first width La on one side in the axial direction perpendicular to the first axis. The first plate-like body C can vibrate around the first axis S1. The first plate-like body C has a first resonance frequency f1. The first plate-like body C resonates with a wave having a first resonance frequency f1 input from the outside and vibrates about the first axis S1.

The second region 3B is divided so as to have a second mass that is larger than the first mass of the first plate-shaped body C. As shown in FIG. The second region 3B is formed in a second plate-like body D having a second width Lb longer than the first width La on the other side in the axial direction perpendicular to the first axis S1. The second plate-like body D can vibrate around the first axis S1. The second plate-like body D has a second resonance frequency f2. The second plate-like body D resonates with a wave having a second resonance frequency f2 input from the outside and vibrates about the first axis S1.

A second mirror support portion 4 that supports the mirror portion M in a separated manner is provided on the first mirror support portion 3 . The second mirror support section 4 has a second axis S2 along a direction orthogonal to the first axis S1. The second mirror supporter 4 is rotatably supported by the first mirror supporter 3 about a second axis S2. The second mirror support portion 4 has, for example, a frame portion 4A formed in an annular shape. The frame portion 4A is formed so as to extend around the mirror portion M. As shown in FIG. A second groove H2 separating the frame portion 4A and the first mirror support portion 3 is formed around the frame portion 4A. The second mirror support portion 4 is formed line-symmetrically with respect to the first axis S1 and the second axis S2.

The second shaft S2 is formed in a torsion bar that elastically deforms in the twisting direction. The second axis S<b>2 is formed by leaving a bar shape with a predetermined width when forming the second groove H<b>2 in the first mirror support portion 3 . The second axis S2 is defined by a third torsion bar S2A that supports one side of the second mirror support section 4 in the X-axis direction and the other side of the second mirror support section 4 in the X-axis direction. and a fourth torsion bar S2B that supports the The third torsion bar S<b>2</b>A connects the first mirror support portion 3 and one axial side of the second mirror support portion 4 along the X-axis direction. The fourth torsion bar S<b>2</b>B connects the second mirror support portion 4 on the other side in the X-axis direction with the first mirror support portion 3 .

The second mirror supporting portion 4 further supports a mirror portion M separately. The mirror portion M is formed in a disc shape. A circular mirror surface M1 is formed on the surface of the mirror portion M. As shown in FIG. A third groove H3 is formed around the mirror portion M to separate the mirror portion M from the second mirror support portion 4 . The mirror portion M has a third axis S3 arranged coaxially with the first axis S1. The third shaft S3 rotatably supports the mirror portion M with respect to the second mirror support portion 4. As shown in FIG. The third shaft is formed on a torsion bar that elastically deforms in the twisting direction.

The third axis S3 consists of a fifth torsion bar S3A that supports one axial side of the mirror portion M along the Y-axis direction, and a sixth torsion bar S3A that supports the other axial side of the mirror portion M along the Y-axis direction. bar S3B. The fifth torsion bar S3A connects one axial side of the mirror portion M along the Y-axis direction and the second mirror support portion 4 . The sixth torsion bar S<b>3</b>B connects the other side of the mirror portion M in the Y-axis direction with the second mirror support portion 4 . The third axis S3 is arranged at a position that divides the mirror portion M evenly in the Y-axis direction.

The second mirror support portion 4 (including the mirror portion M) has a third resonance frequency f3 around the second axis S2. The second mirror support portion 4 resonates with a wave having a third resonance frequency f3 input from the outside and vibrates about the second axis S2.

A first vibration source 5 serving as a vibration source is provided on the first side surface 3P side of the first mirror support portion 3 . The first vibration source 5 includes a first diaphragm 5A that elastically deforms and bends upon receiving an external force. The first diaphragm 5A is formed in a rectangular plate shape. A U-shaped fourth groove H4 separating the first diaphragm 5A and the substrate 2 is formed around the first diaphragm 5A. The fourth groove H4 partially shares the first groove H1 on the first side surface 3P side.

With the above configuration, the first diaphragm 5A is formed into a cantilever capable of vibrating with one axial side along the Y-axis direction as a base end and the other axial side as a tip end. A first electrode 5D is formed extending in a direction orthogonal to the first axis S1 (X-axis) on the other axial side of the first diaphragm 5A along the Y-axis direction. The first electrode 5D is composed of, for example, a wiring layer having a plurality of linear wiring structures.

A pair of wires 5E extending along the Y-axis direction orthogonal to the first electrodes 5D are electrically connected to one axial side and the other axial side of the first electrodes 5D along the X-axis direction. ing. The pair of wires 5E are electrically connected to a pair of terminals 5F provided on one side of the first diaphragm 5A in the axial direction. The pair of terminals 5F are electrically connected to a first power supply section 21, which will be described later. The first electrode 5D, the pair of wires 5E, and the pair of terminals 5F are formed by a wiring layer having a linear wiring structure on the first diaphragm 5A. Therefore, the wiring paths of the first electrode 5D, the pair of wires 5E, and the pair of terminals 5F are simplified.

A second vibration source 6 serving as a vibration source is provided on the second side surface 3Q side of the first mirror support portion 3 . The second vibration source 6 includes a second vibration plate 6A that elastically deforms and bends upon receiving an external force. The second diaphragm 6A is formed in a rectangular plate shape. A U-shaped fifth groove H5 separating the second diaphragm 6A and the substrate 2 is formed around the second diaphragm 6A. The fifth groove H5 partially shares the first groove H1 on the second side surface 3Q side.

With the above configuration, the second diaphragm 6A is formed into a cantilever capable of vibrating with the other axial side along the Y-axis direction as the base end and the one axial side as the distal end. A second electrode 6D is formed extending in a direction perpendicular to the first axis S1 (X-axis) on one side of the second diaphragm 6A in the Y-axis direction. The second electrode 6D is composed of, for example, a wiring layer having a plurality of linear wiring structures.

A pair of wirings 6E extending along the Y-axis direction orthogonal to the second electrode 6D are electrically connected to one axial side and the other axial side of the second electrode 6D along the X-axis direction. ing. The pair of wires 6E are electrically connected to a pair of terminals 6F provided on one axial side of the second diaphragm 6A. A pair of terminals 6F are electrically connected to a second power supply section 22, which will be described later. The second electrode 6D, the pair of wires 6E, and the pair of terminals 6F are formed by printed wiring on the second diaphragm 6A. Therefore, the wiring paths of the second electrode 6D, the pair of wires 6E, and the pair of terminals 6F are simplified. The first vibration source 5 and the second vibration source 6 are arranged between a magnetic field generator 30 that generates a magnetic field B1 in the direction along the first axis S1.

The magnetic field generator 30 includes a first permanent magnet 31 provided adjacent to one side of the first vibration source 5 in the axial direction along the Y-axis direction, and a first permanent magnet 31 provided adjacent to the second vibration source 6 in the axial direction along the Y-axis direction. and a second permanent magnet 32 provided adjacent to the other side. The magnetic field generator 30 generates a magnetic field B1 in the direction from the first permanent magnet 31 to the second permanent magnet, for example. The first permanent magnet 31 and the second permanent magnet 32 are, for example, neodymium magnets. The first permanent magnet 31 is arranged, for example, with its N pole facing the first vibration source 5 . The second permanent magnet 32 is arranged, for example, with the S pole facing the second vibration source 6 . The arrangement direction of the first permanent magnet 31 and the second permanent magnet 32 is not limited to this, and they may be opposite to each other, or may be arranged so that their N poles or S poles face each other.

A current is input to the first electrode 5</b>D from a first power supply section 21 provided in the power supply section 20 . A current is input to the second electrode 6</b>D from a second power supply section 22 provided in the power supply section 20 . The first power supply unit 21 and the second power supply unit 22 have, for example, a power supply circuit that performs AC conversion, down-converting, frequency conversion, and the like on the power supplied from the power supply device 23 . The first power supply unit 21 and the second power supply unit 22 generate AC current adjusted to a predetermined frequency, a predetermined voltage, and a predetermined current based on the power of the power source, and the alternating current is applied to the first electrode 5D and the second electrode 6D, respectively. input. The power supply device 23 supplies power supply power to the first power supply unit 21 and the second power supply unit 22 based on power input from a commercial power supply or a storage battery.

The first power supply unit 21 inputs, for example, an alternating current having a first frequency corresponding to the first resonance frequency f1 to the first electrode 5D. Thereby, as will be described later, a Lorentz force is generated in the first electrode 5D, and the first diaphragm 5A is vibrated at the same frequency as the first resonance frequency f1. Similarly, the first power supply unit 21 inputs an alternating current of a second frequency corresponding to the second resonance frequency f2 to the first electrode 5D to generate a Lorentz force to move the first diaphragm 5A to the first frequency. 2 Vibrate at the same frequency as the resonance frequency f2.

Similarly, the second power supply section 22 inputs an alternating current of a third frequency corresponding to the third resonance frequency f3 to the second electrode 6D. As will be described later, this causes the second electrode 6D to generate a Lorentz force corresponding to the third frequency corresponding to the third resonance frequency f3, thereby vibrating the second diaphragm 6A at the same frequency as the third resonance frequency f3. Let The power supply unit 20 is controlled by the control device 10 .

The control device 10 includes a control unit 12 that controls the power supply unit 20 and a storage unit 14 that stores data necessary for control. The control device 10 is, for example, an information processing device such as a personal computer. The control device 10 and the power supply unit 20 are communicably connected by wire or wireless communication. The control device 10 may be connected to a network and control the power supply unit 20 based on remote control. The network may be, for example, a LAN (Local Area Network), an in-vehicle LAN, a WAN (Wide Area Network), a public wireless communication network, or the like.

The control unit 12 is implemented, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components are hardware such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array) or GPU (Graphics Processing Unit). circuit part; circuit), or by cooperation of software and hardware. The program may be stored in advance in a storage device such as an HDD or flash memory (a storage device having a non-transitory storage medium) provided in the storage unit 14, or may be removable such as a DVD or CD-ROM. It may be stored in a non-transitory storage medium (non-transitory storage medium), and may be installed in the storage device by mounting the storage medium in the drive device.

The control unit 12 controls the wave source unit 40 to output the electromagnetic waves 41 . For example, the wave source unit 40 outputs a laser beam in the case of a light source such as a projector or LiDAR, and outputs an electromagnetic wave in the case of a radar or the like. An electromagnetic wave 41 is input to the mirror surface M1. The control unit 12 controls alternating currents output from the first power supply unit 21 and the second power supply unit 22 .

The control unit 12 controls the first power supply unit 21 to input a predetermined alternating current to the first electrode 5</b>D to vibrate the first vibration source 5 . It resonates with the vibration generated in the first vibration source 5, and the first mirror support portion 3 vibrates around the first axis S1. That is, the control section 12 controls the vibration of the first mirror support section 3 based on the control of the first vibration source 5 .

The control unit 12 controls the second power supply unit 22 to input a predetermined alternating current to the second electrode 6D to vibrate the second vibration source 6. As shown in FIG. It resonates with the vibration generated in the second vibration source 6, and the second mirror support portion 4 vibrates around the second axis S2. That is, the control section 12 controls the vibration of the second mirror support section 4 based on the control of the second vibration source 6 .

The principle of operation of the scanning mirror device 1 will be described below.

As shown in FIG. 2, the first mirror supporter 3 is supported by the substrate 2 so as to be rotatable about the first axis S1. Since the first axis S1 is formed as a torsion bar that elastically deforms in the torsional direction, the first mirror support section 3 vibrates based on the torsional vibration generated around the first axis S1. The first region 3A side of the first mirror support portion 3 has a first resonance frequency f1, and when a wave having the same frequency as the first resonance frequency f1 is input from the outside, the first region 3A is subjected to a force T1 generated at the center of gravity G1. It vibrates by resonance around one axis S1. The second region 3B side of the first mirror supporting portion 3 has a second resonance frequency f2, and when a wave having the same frequency as the second resonance frequency f2 is input from the outside, a force T2 generated at the center of gravity G2 causes a second resonance frequency f2. It vibrates by resonance around one axis S1.

The first mirror supporter 3 vibrates, for example, by resonating with the vibration generated in the adjacent first vibration source 5 . The first vibration source 5 generates, for example, a first wave having the same frequency as the first resonance frequency f1 of the first region 3A, resonates the first region 3A, and rotates the first mirror support 3 around the first axis S1. to vibrate. The first vibration source 5 vibrates the first diaphragm 5A based on the alternating current input to the first electrode 5D. A magnetic field B1 is generated along the Y-axis direction by the magnetic field generator 30 . When an alternating current of the first frequency is input to the first electrode 5D, the Lorentz force periodically acts on the first electrode 5D in the +Z-axis direction and the -Z-axis direction according to the first resonance frequency f1.

The first diaphragm 5A vibrates according to the periodic Lorentz force corresponding to the first resonance frequency f1 acting on the first electrode 5D. Thereby, the first vibration source 5 vibrates at the same frequency as the first resonance frequency f1. When the first vibration source 5 vibrates at the same frequency as the first resonance frequency f1, the first region 3A of the first mirror support portion 3 resonates and vibrates at the first resonance frequency f1. At this time, since the center of gravity G1 of the first region 3A is positioned at the mirror portion M, the force generated by resonance is applied to the mirror portion M. Therefore, the mirror portion M vibrates around the third axis S3. That is, when an alternating current having a first frequency corresponding to the first resonance frequency f1 is input to the first electrode 5D from the first power supply unit 21, the first diaphragm 5A is moved based on the Lorentz force generated in the first electrode 5D. vibrates, and the mirror portion M resonates at the first resonance frequency and vibrates about the third axis S3.

Similarly, the first vibration source 5 generates, for example, a second wave having the same frequency as the second resonance frequency f2 of the second region 3B to resonate the second region 3B and move the first mirror support 3 along the first axis. It vibrates around times S1. The first vibration source 5 vibrates the first diaphragm 5A based on the alternating current input to the first electrode 5D. When the alternating current of the second frequency is input to the first electrode 5D, the Lorentz force periodically acts on the first electrode 5D in the +Z-axis direction and the -Z-axis direction according to the second resonance frequency f2.

The first diaphragm 5A vibrates according to the periodic Lorentz force corresponding to the second resonance frequency f2 acting on the first electrode 5D. Thereby, the first vibration source 5 vibrates at the same frequency as the second resonance frequency f2. When the first vibration source 5 vibrates at the same frequency as the second resonance frequency f2, the second region 3B of the first mirror support portion 3 resonates and vibrates at the second resonance frequency f2.

At this time, the center of gravity G2 of the second region 3B is not positioned on the mirror portion M, so the force generated by resonance is not applied to the mirror portion M. Therefore, the mirror portion M vibrates around the first axis S1 together with the second region 3B. That is, when an alternating current having a second frequency corresponding to the second resonance frequency f2 is input to the first electrode 5D from the first power supply section 21, the first electrode 5D vibrates based on the Lorentz force, and the mirror section M Together with the second region 3B, it resonates at the second resonance frequency f2 and vibrates around the first axis S1.

As shown in FIG. 3, the second mirror supporter 4 is supported by the substrate 2 so as to be rotatable about the second axis S2. Since the second axis S2 is formed as a torsion bar that elastically deforms in the torsional direction, the second mirror support section 4 vibrates based on the torsional vibration that occurs around the second axis S2. The second mirror support part 4 has a third resonance frequency f3, and when a wave having the same frequency as the third resonance frequency f3 is input from the outside, the second mirror support part 4 resonates about the second axis S2 based on the force T3 generated at the center of gravity G3. vibrate.

The second mirror support part 4 vibrates by resonating with the vibration generated in the adjacent second vibration source 6, for example. The second vibration source 6 generates, for example, a third wave having the same frequency as the third resonance frequency f3 of the second mirror support portion 4 to resonate the second mirror support portion 4, causing the second mirror support portion 4 to vibrate at the second frequency. Vibrate around the axis S2. The second vibration source 6 vibrates the second diaphragm 6A based on the alternating current input to the second electrode 6D. A magnetic field B1 is generated along the Y-axis direction by the magnetic field generator 30 . When an alternating current having a third frequency corresponding to the third resonance frequency f3 is input to the second electrode 6D, the second electrode 6D is periodically charged in the +Z-axis direction and the -Z-axis direction according to the third resonance frequency f3. Lorentz force acts on

The second diaphragm 6A vibrates according to the periodic Lorentz force corresponding to the third resonance frequency f3 acting on the second electrode 6D. Thereby, the second vibration source 6 vibrates at the same frequency as the third resonance frequency f3. When the second vibration source 6 vibrates at the same frequency as the third resonance frequency f3, the second mirror supporter 4 resonates and vibrates at the third resonance frequency f3. That is, when the second power supply unit 22 inputs the alternating current of the third frequency corresponding to the third resonance frequency f3 to the second electrode 6D, the second diaphragm 6A is driven by the Lorentz force generated in the second electrode 6D. vibrates, and the second mirror support portion 4 resonates at the third resonance frequency f3 and vibrates about the second axis S2.

As described above, in the scanning mirror device 1 , the first mirror supporter 3 and the second mirror supporter 4 are separated from the first vibration source 5 and the second vibration source 6 . Therefore, in the scanning mirror device 1, even if the first vibration source 5 and the second vibration source 6 are heated during driving, the heat is not transferred to the first mirror support portion 3 and the second mirror support portion 4. It is possible to prevent the first mirror supporting portion 3 and the second mirror supporting portion 4 from being distorted and the resonance frequency from being changed, so that the apparatus can be operated stably.

FIG. 4 shows the state of the mirror portion M vibrating at the first frequency. The mirror portion M resonates with the same vibration as the first resonance frequency f1 generated in the first vibration source 5 and vibrates around the third axis S3 (first axis S1) along the Y-axis direction. In the scanning mirror device 1 according to the embodiment, the first resonance frequency f1 is 2.582 kHz, for example.

FIG. 5 shows the state of the second region 3B vibrating at the second frequency. The second region 3B, together with the mirror portion M, resonates with the same vibration as the second resonance frequency f2 generated in the first vibration source 5 and vibrates around the first axis S1 along the Y-axis direction. In the scanning mirror device 1 according to the embodiment, the second resonance frequency f2 is 234 Hz, for example. The mirror portion M can be vibrated at a high speed at a first frequency and can be vibrated at a low speed at a second frequency which is lower than the first frequency.

FIG. 6 shows the state of the mirror portion M vibrating at the third frequency. The mirror portion M resonates with the same vibration as the third resonance frequency f3 generated in the first vibration source 5 and vibrates around the second axis S2 along the X-axis direction. In the scanning mirror device 1 according to the embodiment, the third resonance frequency f3 is 1.461 kHz, for example. The third frequency is a value different from the first frequency and the second frequency.

Therefore, according to the scanning mirror device 1, the waves of the first frequency or the second frequency are generated from the first vibration source 5, and the waves of the third frequency different from the first frequency and the second frequency are generated from the second vibration source 6. By generating waves, the vibration of the mirror portion M about the first axis S1 and the vibration about the second axis S2 can be separately controlled.

FIG. 7 shows a state in which the mirror portion M vibrates along the Z-axis direction based on the fourth frequency. In addition to the mode of vibration about the first axis S1 and the second axis S2, the mirror section M may also have a mode of vibration along the Z-axis based on the force T4 generated at the center of the mirror section M. The fourth frequency at this time is, for example, 945 Hz.

FIG. 8 shows locations where displacement was measured in the performance test of the fabricated scanning mirror device 1 . Displacement was measured at each measurement point using a laser Doppler instrument. The displacement when the mirror portion M vibrates around the first axis S1 (Y-axis) was measured at the Y-axis measurement point. The displacement when the mirror portion M vibrates around the second axis S2 (X-axis) was measured at the X-axis measurement point.

FIG. 9 shows measurement results of a performance test of the scanning mirror device 1. As shown in FIG. As shown, the vibration mode about the first axis S1 (Y-axis) and the vibration mode about the second axis S2 (X-axis) are measured. In addition, a vibration mode around the X-axis, which is not used in the scanning mirror device 1, was measured near 1.75 kHz. Also, at 945 Hz, the vibration mode along the Z-axis, which is not used in the scanning mirror device 1, was measured.

FIG. 10 shows scanning light generated by irradiating the driven scanning mirror device 1 with laser light. As shown, according to the scanning mirror device 1, the mirror portion M is vibrated around the first axis S1 and around the second axis S2 to scan the laser light on a two-dimensional plane, A two-dimensional image-like projection can be realized.

As described above, according to the scanning mirror device 1, the vibration of the mirror portion M about the first axis S1 and the vibration about the second axis S2 are independently controlled based on the first vibration source 5 and the second vibration source 6. can be controlled to According to the scanning mirror device 1, since the first mirror support section 3 and the second mirror support section 4 provided with the mirror section M are separated from the first vibration source 5 and the second vibration source 6, Heat generated in the first vibration source 5 and the second vibration source 6 is prevented from being transmitted to the first mirror support portion 3 and the second mirror support portion 4 . According to the scanning mirror device 1, since the heat generated in the first vibration source 5 and the second vibration source 6 is not transmitted to the first mirror support portion 3 and the second mirror support portion 4, the mirror portion M is distorted. Also, the resonance frequency is prevented from changing, and the device can be operated stably.

Modifications of the scanning mirror device 1 will be described below. In the following description, the same names and reference numerals are used for the same configurations as in the above embodiment, and duplicate descriptions are omitted as appropriate.
[Modification]
The magnetic field generator 30 may generate the magnetic field B<b>1 with the pair of first permanent magnet 31 and the second permanent magnet 32 , or may generate the magnetic field with an electromagnetic coil. The first vibration source 5 and the second vibration source 6 may be mechanical actuators in addition to the illustrated electromagnetic actuators. For example, the first vibration source 5 and the second vibration source 6 may be composed of vibrating films using piezo elements. The first vibration source 5 and the second vibration source 6 may be composed of a vibrator using a motor and a weight, or a linear actuator using a solenoid coil. Any source may be used as the first vibration source 5 and the second vibration source 6 as long as they can generate vibration of a predetermined frequency.

The first vibration source 5 and the second vibration source 6 may not necessarily be provided adjacent to the first mirror support section 3, and may be provided at arbitrary positions as long as the mirror section M can be driven based on resonance. may have been Further, the first mirror supporting portion 3 is divided into the first region 3A and the second region 3B, and the first region 3A is adjusted to the first mass and the second region 3B is adjusted to the second mass. The first mirror support portion 3 and the mirror portion M may be formed in any shape. may be adjusted based on the arrangement position of

An embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the scope of the invention. For example, the scanning mirror device may be used not only for light sources and LiDAR, but also for three-dimensional measurement devices using ultrasonic waves and electromagnetic waves.

1 Scanning Mirror Device 3 First Mirror Support Part 3A First Area 3B Second Area 4 Second Mirror Support Part 5 First Vibration Source 5A First Diaphragm 5D First Electrode 6 Second Vibration Source 6A Second Diaphragm 6D Second electrode 20 Power source 21 First power source 22 Second power source 30 Magnetic field generator B1 Magnetic field C First plate D Second plate M Mirror M1 Mirror surface S1 First axis S2 Second axis S3 3 axes

Claims (8)

a mirror section having a mirror surface;
a first mirror support portion that supports the mirror portion;
A first mirror supporting part rotatably supported at a position where the first mirror supporting part is divided into a first region having a first mass and a second region having a second mass larger than the first mass. axis and
a first vibration source that generates a first wave having the same frequency as the first resonance frequency of the first region, resonates the first region, and vibrates the first mirror support portion about the first axis. ,
Scanning mirror device. The first vibration source generates a second wave having the same frequency as the second resonance frequency of the second region, resonates the second region, and vibrates the first mirror support portion around the first axis.
2. A scanning mirror device according to claim 1. The first mirror support part is formed in a plate shape,
The first shaft is formed on a torsion bar that elastically deforms in a torsional direction,
The first region is formed on a first plate-shaped body having a first width on one side of the first mirror supporting portion in a direction perpendicular to the first axis,
The second region is formed in a second plate-shaped body having a second width longer than the first width on the other side of the first mirror support portion in a direction orthogonal to the first axis,
3. A scanning mirror device according to claim 1 or 2. A magnetic field generator that generates a magnetic field in a direction along the first axis,
The first vibration source includes a first diaphragm elastically deformed and bent by receiving an external force, and a first electrode formed on the first diaphragm along a direction orthogonal to the first axis. ,
An alternating current having the same frequency as the first resonance frequency is input to the first electrode, and the first diaphragm is vibrated based on the Lorentz force generated in the first electrode by the magnetic field to vibrate the first region. a first power supply section that resonates and vibrates at the first resonance frequency,
A scanning mirror device according to any one of claims 1 to 3. The first power supply unit inputs an alternating current having the same second resonance frequency as the second region to the first electrode, vibrates the first electrode based on Lorentz force, and causes the second region to move to the second region. Resonate and vibrate with two resonance frequencies,
5. A scanning mirror device according to claim 4. a second mirror support part that separates and supports the mirror part in the first mirror support part;
a second axis perpendicular to the first axis that rotatably supports the second mirror support section on the first mirror support section;
A second vibration source that generates a second wave having the same frequency as the third resonance frequency of the second mirror support section, resonates the second mirror support section, and vibrates the second mirror support section about the second axis. and
6. A scanning mirror device according to claim 5. The second mirror support part is formed in a plate shape,
The second shaft is formed on a torsion bar that elastically deforms in a twisting direction,
The second vibration source includes a second diaphragm elastically deformed and bent by receiving an external force, and a second electrode formed on the second diaphragm along a direction perpendicular to the first axis. ,
An alternating current having the same frequency as the third resonance frequency is input to the second electrode to vibrate the second diaphragm based on the Lorentz force generated in the second electrode by the magnetic field, and the second mirror support portion is provided. a second power supply unit that resonates at the third resonance frequency and vibrates about the second axis,
7. A scanning mirror device according to claim 6. The mirror section is separately supported by the second mirror support section,
a third shaft that rotatably supports the mirror portion with respect to the second mirror support portion and that is arranged coaxially with the first shaft;
The third shaft is formed on a torsion bar that elastically deforms in a torsional direction,
The first power supply unit inputs an alternating current having the same frequency as the first resonance frequency to the first electrode, and vibrates the first diaphragm based on a Lorentz force generated in the first electrode by the magnetic field. and vibrating the mirror portion around the third axis by resonating at the first resonance frequency;
8. A scanning mirror device according to claim 7.

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