MEMS mirrors and MEMS mirror array systems

Abstract

To provide a MEMS mirror with which it is possible to adjust an eigen frequency, and a MEMS mirror array system which is equipped with a MEMS mirror array having a plurality of MEMS mirrors.SOLUTION: Provided is a MEMS mirror 100 comprising a flat plate 10A which is displaceable in the direction of film thickness, a frame part 10 which is separate from the flat plate 10A and encloses the flat plate 10A, a support part (shank 10B and / or beam part 10C) that connects the flat plate 10A and the frame part 10 and is smaller in film thickness than the frame part 10, and a piezoelectric substance 14 for control which is located upward of the support part. The spring constant of the support part is adjusted by the deformation of the support part that is associated with the deformation of the piezoelectric substance 14 for control that is caused by application of a control voltage to the piezoelectric substance 14 for control.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This embodiment relates to a MEMS mirror and a MEMS mirror array system.

Background Art

[0002] In a device having a movable flat plate such as a MEMS mirror, the flat plate is displaced in the film thickness direction by a Coulomb force (electrostatic), a Lorentz force (electromagnetic), a piezoelectric stress (piezoelectric), or the like. Due to this displacement, stress is generated in the support portion that supports the flat plate, and a torsional force or the like is applied to the support portion by the stress. As a result, vibration occurs in the flat plate. The inclination of the flat plate due to the vibration becomes the most efficient state when driven at the resonance frequency (natural frequency) of the flat plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there are structural variations in the size, thickness, etc. in the manufacturing process of the movable flat plate, and along with this variation, there is also a variation in the spring constant of the portion that functions as a spring for moving the flat plate. As a result, the natural frequency, which is the optimal driving frequency of the device, varies from device to device, and it is important to know the natural frequency of each individual device when using the device. Further, when the driving frequency of the device is predetermined, if the natural frequency deviates from the driving frequency, it leads to a decrease in efficiency. Also, it is difficult to inspect each time the natural frequency deviates from the driving frequency and adjust the driving frequency.

[0005] One aspect of this embodiment aims to provide a MEMS mirror array system comprising a MEMS mirror capable of adjusting its natural frequency, and a MEMS mirror array having a plurality of such MEMS mirrors. [Means for solving the problem]

[0006] One aspect of this embodiment includes a flat plate that is displaceable in the film thickness direction, a frame portion that is spaced apart from the flat plate and surrounds the flat plate, and a support portion that connects the flat plate and the frame portion and has a film thickness smaller than that of the frame portion. The support portion comprises a beam portion in the shape of a double-supported beam, with both ends connected to the frame portion, and a shaft portion in the shape of a double-supported beam, with one end connected to the flat plate and the other end connected to the beam portion, and further comprises a control piezoelectric element arranged across the shaft portion and the beam portion. This MEMS mirror adjusts the spring constant of the support portion by the deformation of the support portion resulting from the deformation of the control piezoelectric element when a control voltage is applied to the control piezoelectric element.

[0007] Another aspect of this embodiment includes a MEMS mirror array having a plurality of the above-mentioned MEMS mirrors on a base, Multiple of the above Each of the MEMS mirrors The aforementioned Applying to the control piezoelectric element The aforementioned This is a MEMS mirror array system comprising a drive control unit that controls the control voltage. [Effects of the Invention]

[0008] According to this embodiment, it is possible to provide a MEMS mirror capable of adjusting its natural frequency, and a MEMS mirror array system comprising a MEMS mirror array having a plurality of such MEMS mirrors. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a plan view showing a MEMS mirror according to this embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along the line II-II in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along the line III-III in Figure 1. [Figure 4] Figure 4 is a plan view showing a MEMS mirror according to a modified example 1 of this embodiment. [Figure 5]Figure 5 is a cross-sectional view along the VV line in Figure 4. [Figure 6] Figure 6 is a cross-sectional view along the line VI-VI in Figure 4. [Figure 7] Figure 7 is a plan view showing a MEMS mirror according to a modified example 2 of this embodiment. [Figure 8] Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 7. [Figure 9] Figure 9 is a cross-sectional view along the line IX-IX in Figure 7. [Figure 10] Figure 10 is a plan view showing a MEMS mirror according to a modified example 3 of this embodiment. [Figure 11] Figure 11 is a cross-sectional view along the line XI-XI in Figure 10. [Figure 12] Figure 12 is a cross-sectional view along the line XII-XII in Figure 10. [Figure 13] Figure 13 is a plan view showing a MEMS mirror according to a modified example 4 of this embodiment. [Figure 14] Figure 14 is a block diagram showing the MEMS mirror array system according to this embodiment. [Modes for carrying out the invention]

[0010] Next, this embodiment will be described with reference to the drawings. In the drawings described below, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and planar dimensions of each component may differ from reality. Therefore, specific thicknesses and dimensions should be determined by referring to the following explanation. Furthermore, it goes without saying that there are parts in the drawings where the relationships and ratios of dimensions differ from those of other parts.

[0011] Furthermore, the embodiments described below are illustrative examples of devices and methods for realizing the technical concept, and do not specify the material, shape, structure, arrangement, etc., of each component. Various modifications can be made to these embodiments within the scope of the claims.

[0012] One aspect of a specific embodiment of the present invention is as follows.

[0013] <1> A MEMS mirror comprising: a flat plate displaceable in the film thickness direction; a frame portion spaced apart from and surrounding the flat plate; a support portion connecting the flat plate and the frame portion and having a smaller film thickness than the frame portion; and a control piezoelectric body disposed on the support portion, wherein the spring constant of the support portion is adjusted by deformation of the support portion accompanying deformation of the control piezoelectric body due to application of a control voltage to the control piezoelectric body.

[0014] <2> The MEMS mirror according to <1>, wherein the support portion has a double-clamped beam-shaped shaft portion disposed between the flat plate and the frame portion, with one end connected to the flat plate and the other end connected to the frame portion.

[0015] <3> The MEMS mirror according to <l>, wherein the support portion includes a double-clamped beam-shaped beam portion with both ends connected to the frame portion, and a double-clamped beam-shaped shaft portion with one end connected to the flat plate and the other end connected to the beam portion.

[0016] According to <1> to <3>, when a control voltage is applied to the control piezoelectric body, the control piezoelectric body is deformed, and along with the deformation of the control piezoelectric body, the support portion including the shaft portion and / or the beam portion is also deformed. Since the spring constant of the support portion changes due to the deformation of the support portion, as a result, the natural frequency of the flat plate and the MEMS mirror can be adjusted by adjusting the control voltage applied to the control piezoelectric body.

[0017] <4> The MEMS mirror according to any one of <1> to <3>, wherein the support portion is made of the same material as the flat plate.

[0018] <5> The MEMS mirror according to any one of <1> to <4>, wherein the support portion is made of the same material as the frame portion.

[0019] <6> The MEMS mirror according to any one of <1> to <5>, wherein the materials of the flat plate and the support portion include silicon.

[0020] <4> ~ <6> According to this, by having the frame, flat plate, and support portion including the shaft and / or beam portion made of the same material, each can be formed as a single unit, making the manufacturing process simpler.

[0021] <7> On the base, <1> ~ <6> A MEMS mirror array system comprising: a MEMS mirror array having a plurality of MEMS mirrors as described in any one of the items; and a drive control unit that controls the control voltage applied to each of the control piezoelectric elements of the plurality of MEMS mirrors.

[0022] <7> According to this, it becomes possible to align the natural frequencies of multiple MEMS mirrors in a MEMS mirror array, or to adjust the natural frequencies of some of the MEMS mirrors, allowing for efficient driving of individual MEMS mirrors when multiple MEMS mirrors are driven synchronously.

[0023] <MEMSミラー> The MEMS mirror according to this embodiment will be described with reference to the drawings.

[0024] Figure 1 is a plan view showing a MEMS mirror according to this embodiment. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. Figure 3 is a cross-sectional view taken along line III-III in Figure 1. The MEMS mirror 100 of this embodiment includes a flat plate 10A that is displaceable in the film thickness direction, a frame portion 10 that is spaced apart from the flat plate 10A and surrounds the flat plate 10A, a shaft portion 10B that connects the flat plate 10A and the frame portion 10 and has a smaller film thickness than the frame portion 10, a control piezoelectric element 14 disposed on the shaft portion 10B, wiring 16 that is electrically connected to the control piezoelectric element 14 and controls the control piezoelectric element 14, and wiring 12 disposed on the outer edge of the flat plate 10A, on the shaft portion 10B, and on the frame portion 10. Although not shown, wiring 12 and wiring 16 are electrically connected to a drive control unit which will be described later. The control piezoelectric element 14 is positioned on each of the two shaft portions 10B that are provided so as to sandwich the flat plate 10A.

[0025] Furthermore, in this specification, "electrically connected" includes cases where connections are made via "something that has some kind of electrical function." Here, "something that has some kind of electrical function" is not particularly limited as long as it enables the exchange of electrical signals between the connected objects. For example, "something that has some kind of electrical function" includes electrodes, wiring, switching elements, resistive elements, inductors, capacitive elements, and other elements with various functions.

[0026] In this embodiment, the longitudinal direction in which the shaft portion 10B extends linearly is defined as the Y direction, the direction perpendicular to the Y direction and parallel to the upper surface of the flat plate 10A is defined as the X direction, and the direction corresponding to the thickness of the flat plate 10A is defined as the Z direction. In other words, the Z direction is perpendicular to both the X and Y directions. Furthermore, the direction in which the control piezoelectric element 14 is located as viewed from the frame portion 10 is defined as the upward direction, and the direction in which the frame portion 10 is located as viewed from the control piezoelectric element 14 is defined as the downward direction. In the following description, the upward and downward directions are defined based on the state of the MEMS mirror 100 shown in Figure 2, but this does not limit the direction in which the MEMS mirror 100 can be used.

[0027] Each of the frame portion 10, the flat plate 10A, and the shaft portion 10B is formed, for example, by processing a base made of silicon (the base 110 shown in Figure 14, which will be described later). In other words, the frame portion 10, the flat plate 10A, and the shaft portion 10B are made of the same material, and the manufacturing process can be simplified by forming each of them as a single unit.

[0028] The shaft portion 10B is a cantilevered beam with both ends fixed, one end connected to the flat plate 10A and the other end connected to the frame portion 10, and is positioned between the flat plate 10A and the frame portion 10. When the flat plate 10A is moved, the shaft portion 10B functions as a spring to assist the movement of the flat plate 10A, adjusts the spring constant when the shaft portion 10B functions as a spring by its own deformation, and also functions as a support portion that supports the flat plate 10A. The shaft portion 10B can be formed when processing the base by etching it so that the film thickness is smaller than that of the frame portion 10.

[0029] A control piezoelectric element 14 is positioned on the support shaft 10B, and a control voltage is applied to the control piezoelectric element 14 via wiring 16, causing it to deform. As the control piezoelectric element 14 deforms, both ends of the shaft 10B deform in a way that causes them to pull against each other, making the shaft 10B stiffer and increasing its spring constant. By adjusting the control voltage applied to the control piezoelectric element 14, the control piezoelectric element 14 deforms, and the shaft 10B deforms accordingly. As a result, the spring constant of the shaft 10B can be adjusted, and the natural frequency of the flat plate 10A connected to the shaft 10B can be adjusted. Furthermore, because the control piezoelectric element is positioned on each of the two shafts 10B, the difference in the spring function of the two shafts 10B can be reduced, making the twisting of each shaft 10B uniform and thus the load on each shaft 10B uniform. By achieving the above-mentioned homogenization, rotational vibration with a constant period in the XZ plane can be realized.

[0030] The control voltage can be, for example, 0V or any fixed voltage, a sine wave between 0 and 5V, a unipolar pulse, a bipolar pulse, a burst wave, a continuous wave, etc. Furthermore, the voltage applied to the control piezoelectric element 14 can be a modulated voltage using a filter or the like. For example, the voltage applied to one electrode (such as electrode 14a, described later) can be modulated and applied to another electrode (such as electrode 14c, described later). This reduces the number of electrode pads and the types of driving voltages applied, simplifying the manufacturing process.

[0031] Wiring 12 functions as a metal coil, and by passing current through wiring 12, which is positioned on the outer edge of plate 10A, a Lorentz force is generated according to Fleming's law, causing plate 10A to tilt. Specifically, if wiring 12, which functions as a metal coil, is positioned perpendicular to the magnetic field (the direction of the magnetic force is the X direction), and current is passed in the direction of arrow 20 shown in Figure 1, a Lorentz force is applied to wiring 12 in the Z direction. The magnitude of the Lorentz force is proportional to the strength of the current and the magnetic field.

[0032] As shown in Figure 3, the flat plate 10A is configured to be displaceable in the film thickness direction (Z direction). Specifically, by making the shaft portion 10B function as a rotation axis and separating it from the frame portion 10, the flat plate 10A can be displaced in the film thickness direction due to the Lorentz force.

[0033] Furthermore, a mirror 10a is provided on the flat plate 10A, and the mirror 10a tilts in accordance with the tilt of the flat plate 10A. By adjusting the spring constant of the shaft portion 10B and the Lorentz force, the mirror 10a can be rotated along its axis of rotation in the Y direction and rotated and vibrated in the XZ plane. This changes the optical path of the laser light incident on the mirror surface, allowing the MEMS mirror 100 to be driven at the natural frequency that provides the most efficient operation.

[0034] The mirror 10a is not particularly limited as long as it has a mirror surface that reflects laser light or the like, and may be, for example, a metal layer with a reflectivity of 90% or more formed by vapor deposition or printing.

[0035] Wires 12 and 16 can be made of, for example, copper wire, aluminum wire, and copper-clad aluminum wire (CCAW). Wires 12 and 16 may also be coated with an insulating film, which may be made of, for example, enamel or resin.

[0036] The control piezoelectric element 14 is a piezoelectric element and consists of a pair of electrodes 14a and 14c and a piezoelectric film 14b sandwiched between the pair of electrodes 14a and 14c. The pair of electrodes 14a and 14c and the piezoelectric film 14b are, for example, rectangular in shape.

[0037] Each of the pair of electrodes 14a and 14c is formed using a thin film of a conductive metal, such as platinum, molybdenum, iridium, or titanium. One electrode 14c is located above the piezoelectric film 14b and is connected to wiring 16 for applying a control voltage to electrode 14c. The other electrode 14a is located below the piezoelectric film 14b and is connected to wiring 16 for applying a control voltage to electrode 14a.

[0038] The piezoelectric film 14b is composed of, for example, lead zirconate titanate (PZT). In addition to lead zirconate titanate, the piezoelectric film 14b can also be made of aluminum nitride (AlN), zinc oxide (ZnO), or lead titanate (PbTiO3).

[0039] When control voltages are applied to electrodes 14a and 14c, a potential difference is generated between electrodes 14a and 14c. This potential difference causes the control piezoelectric element 14 to deform. As described above, the deformation of the control piezoelectric element 14 causes the shaft portion 10B to deform, and as a result, the natural frequency of the flat plate 10A changes. In this embodiment, the natural frequency of the MEMS mirror 100 can be adjusted by adjusting the control voltage applied to the control piezoelectric element 14.

[0040] <First variation> The configuration of the MEMS mirror 100A in this modified example will be explained using Figures 4 to 6. Figure 4 is a plan view showing the MEMS mirror 100A. Figure 5 is a cross-sectional view along the line VV in Figure 4. Figure 6 is a cross-sectional view along the line VI-VI in Figure 4. The modified MEMS mirror 100A comprises a flat plate 10A that is displaceable in the film thickness direction, a frame portion 10 that is spaced apart from the flat plate 10A and surrounds the flat plate 10A, a beam portion 10C whose both ends are connected to the frame portion 10 and which has a smaller film thickness than the frame portion 10, a shaft portion 10B that connects the flat plate 10A and the beam portion 10C and which has a smaller film thickness than the frame portion 10, a control piezoelectric element 14 disposed on the beam portion 10C, wiring 16 that is electrically connected to the control piezoelectric element 14 and controls the control piezoelectric element 14, and wiring 12 disposed on the outer edge of the flat plate 10A, on the beam portion 10C, on the shaft portion 10B, and on the frame portion 10. The difference between the MEMS mirror 100A in this modified version and the MEMS mirror 100 shown in Figures 1 to 3 above is that the control piezoelectric element 14 is disposed on the beam portion 10C instead of being disposed on the shaft portion 10B. In this modified example, the points that are common with the MEMS mirror 100 shown in Figures 1 to 3 will be explained by referring to the above description, and the differences will be explained below.

[0041] The beam portion 10C is positioned between the groove portion 18 provided in the frame portion 10 and the region (space) separated from the frame portion 10 and the flat plate 10A, and has a cantilevered beam shape with both ends fixed to the frame portion 10. When the flat plate 10A is moved, the beam portion 10C functions as a spring that assists the movement of the flat plate 10A, adjusts the spring constant when the beam portion 10C functions as a spring by its own deformation, and also functions as a support portion that supports the flat plate 10A. The beam portion 10C can be formed when processing the base by etching it so that the film thickness is smaller than that of the frame portion 10.

[0042] A control piezoelectric element 14 is positioned on the support beam 10C, and a control voltage is applied to the control piezoelectric element 14 via wiring 16, causing it to deform. As the control piezoelectric element 14 deforms, both ends of the beam 10C deform in a way that causes them to pull against each other, making the beam 10C stiffer and increasing its spring constant. By adjusting the control voltage applied to the control piezoelectric element 14, the control piezoelectric element 14 deforms, and the beam 10C also deforms as a result of this deformation. Consequently, the spring constant of the beam 10C can be adjusted, and the natural frequency of the flat plate 10A connected to the support, including the shaft 10B and the beam 10C, can be adjusted.

[0043] As described above, when a control voltage is applied to electrodes 14a and 14c of the control piezoelectric element 14, a potential difference is generated between electrodes 14a and 14c. This potential difference causes the control piezoelectric element 14 to deform, and the beam portion 10C deforms in conjunction with the deformation of the control piezoelectric element 14, resulting in a change in the natural frequency of the flat plate 10A. In this modified example, the natural frequency of the MEMS mirror 100A can be adjusted by adjusting the control voltage applied to the control piezoelectric element 14.

[0044] <Second variation> The configuration of the MEMS mirror 100B in this modified example will be explained using Figures 7 to 9. Figure 7 is a plan view showing the MEMS mirror 100B. Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 7. Figure 9 is a cross-sectional view along the line IX-IX in Figure 7. The modified MEMS mirror 100B comprises a flat plate 10A that is displaceable in the film thickness direction, a frame portion 10 that is spaced apart from the flat plate 10A and surrounds the flat plate 10A, beam portions 10C whose ends are connected to the frame portion 10 and which have a smaller film thickness than the frame portion 10, a shaft portion 10B that connects the flat plate 10A and the beam portion 10C and which has a smaller film thickness than the frame portion 10, a control piezoelectric element 14 that is continuously arranged on the shaft portion 10B and the beam portion 10C, wiring 16 that is electrically connected to the control piezoelectric element 14 and for controlling the control piezoelectric element 14, and wiring 12 arranged on the outer edge of the flat plate 10A, on the beam portion 10C, on the shaft portion 10B, and on the frame portion 10. The difference between the MEMS mirror 100B in this modified version and the MEMS mirror 100A shown in Figures 4 to 6 above is that the control piezoelectric element 14 is arranged on the shaft portion 10B and the beam portion 10C. In this modified example, the points common to the MEMS mirror 100A shown in Figures 4 to 6 will be explained by referring to the above description, and the differences will be explained below.

[0045] Since the control piezoelectric element 14 is positioned on the shaft portion 10B and the beam portion 10C, the shaft portion 10B and the beam portion 10C deform in conjunction with the deformation of the control piezoelectric element 14 caused by the application of a control voltage to the control piezoelectric element 14. If the spring constant of the shaft portion 10B and the spring constant of the beam portion 10C are different, the natural frequency of the flat plate 10A connected to the support portion including the shaft portion 10B and the beam portion 10C can be adjusted more precisely by adjusting the positional relationship between the control piezoelectric element 14 and the shaft portion 10B and the beam portion 10C.

[0046] As described above, when a control voltage is applied to electrodes 14a and 14c of the control piezoelectric element 14, a potential difference is generated between electrodes 14a and 14c. This potential difference causes the control piezoelectric element 14 to deform, and as the control piezoelectric element 14 deforms, the shaft portion 10B and the beam portion 10C deform, resulting in a change in the natural frequency of the flat plate 10A. In this modified example, the force required to deform the support portion is smaller compared to the case where the control piezoelectric element 14 is located on either the shaft portion 10B or the beam portion 10C, so the potential difference between electrodes 14a and 14c can be reduced, and the natural frequency of the flat plate 10A can be adjusted with a small control voltage. In this modified example, the natural frequency of the MEMS mirror 100B can be adjusted by adjusting the control voltage applied to the control piezoelectric element 14.

[0047] <Third variation> The configuration of the MEMS mirror 100C in this modified example will be explained using Figures 10 to 12. Figure 10 is a plan view showing the MEMS mirror 100C. Figure 11 is a cross-sectional view along the line XI-XI in Figure 10. Figure 12 is a cross-sectional view along the line XII-XII in Figure 10. The modified MEMS mirror 100C comprises a flat plate 10A that is displaceable in the film thickness direction, a frame portion 10 that is spaced apart from the flat plate 10A and surrounds the flat plate 10A, a beam portion 10C whose both ends are connected to the frame portion 10 and which has a smaller film thickness than the frame portion 10, a shaft portion 10B that connects the flat plate 10A and the beam portion 10C and which has a smaller film thickness than the frame portion 10, a control piezoelectric element 14A disposed on the shaft portion 10B, a control piezoelectric element 14B disposed on the beam portion 10C, wiring 16A for controlling the control piezoelectric element 14A, wiring 16B for controlling the control piezoelectric element 14B, and wiring 12 disposed on the outer edge of the flat plate 10A, on the shaft portion 10B, and on the frame portion 10. The difference between the MEMS mirror 100C in this modified example and the MEMS mirror 100A shown in Figures 4 to 6 is that it is equipped with control piezoelectric elements 14A and 14B instead of the control piezoelectric element 14 which is continuously arranged on the shaft portion 10B and the beam portion 10C. The points that are common to the MEMS mirror 100A shown in Figures 4 to 6 in this modified example will be explained by referring to the above explanation, and the points that differ will be explained below.

[0048] The description of control piezoelectric elements 14A and 14B can be made by referring to the description of control piezoelectric element 14 above. The description of wiring 16A and 16B can be made by referring to the description of wiring 16 above.

[0049] Since the control piezoelectric element 14A is positioned on the shaft portion 10B and the control piezoelectric element 14B is positioned on the beam portion 10C, the shaft portion 10B and the beam portion 10C deform in conjunction with the deformation of the control piezoelectric elements 14A and 14B caused by the application of a control voltage to them. When the shaft portion 10B on which the control piezoelectric element 14A is positioned and the beam portion 10C on which the control piezoelectric element 14B is positioned are connected and considered as a single support portion, the force required to deform the support portion is smaller compared to when the control piezoelectric element 14 is positioned on either the shaft portion 10B or the beam portion 10C. Therefore, the potential difference between electrodes 14a and 14c can be reduced, and the natural frequency of the flat plate 10A can be adjusted with a small control voltage. In this modified example, the natural frequency of the MEMS mirror 100C can be adjusted by adjusting the control voltage applied to the control piezoelectric elements 14A and 14B.

[0050] (Other embodiments) As stated above, one embodiment has been described, but the descriptions and drawings that constitute part of the disclosure are illustrative and should not be understood as limiting. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. Thus, this embodiment includes various embodiments and the like that are not described herein.

[0051] For example, Figure 13 is a plan view showing the MEMS mirror 100D, and the control piezoelectric element 14 may be positioned on only one of the two shaft portions 10B that are provided to sandwich the flat plate 10A.

[0052] <MEMSミラーアレイシステム> The MEMS mirror array system according to this embodiment will be described with reference to the drawings.

[0053] Figure 14 is a block diagram showing the MEMS mirror array system according to this embodiment. The MEMS mirror array system 200 of this embodiment includes a MEMS mirror array 150 having a plurality of the aforementioned MEMS mirrors (for example, MEMS mirrors 100) on a base 110, and a drive control unit 120 that controls the control voltage applied to each of the control piezoelectric elements 14 of the plurality of MEMS mirrors 100.

[0054] The control piezoelectric element 14 is subject to characteristic variations due to factors such as the size of the piezoelectric film, the crystal properties of the piezoelectric film, the quality including minute defects, environmental factors such as temperature, and deterioration over time. However, the MEMS mirror array system 200 of this embodiment can adjust the natural frequencies of each MEMS mirror 100, which are affected by such characteristic variations and the changes caused by the flat plate 10A of the MEMS mirror 100, as described above, and which vary depending on the environment and conditions.

[0055] The base 110 is not particularly limited as long as it is a base on which the MEMS mirror array 150 is placed, and may be, for example, a silicon substrate. If the base 110 is a silicon substrate, the frame portion 10, the flat plate 10A, and the shaft portion 10B of the MEMS mirror 100 can be formed by processing the base 110. In other words, the base 110, the frame portion 10, the flat plate 10A, and the shaft portion 10B can be made of the same material and each can be formed as a single unit, making the manufacturing process simpler.

[0056] The drive control unit 120 includes, for example, a general-purpose microcomputer comprising a storage unit, a control unit, and an input / output unit (not shown). In this case, the microcomputer may have a computer program installed that allows it to function as a MEMS mirror array system 200. By executing the computer program, the microcomputer controls the multiple MEMS mirrors 100 provided by the MEMS mirror array system 200. The control of the multiple MEMS mirrors 100 may be performed by software, or by providing dedicated hardware. Alternatively, the multiple MEMS mirrors 100 may be controlled by individual hardware.

[0057] The memory unit consists of ROM (Read Only Memory), RAM (Random Access Memory), hard disk, etc. The memory unit stores information such as the drive voltage and natural frequency of each MEMS mirror 100 as data. The memory unit that stores these various data may be configured as physically or logically separated areas within a single storage device, or it may be configured so that each data storage unit is provided in multiple physically different storage devices.

[0058] The control unit includes a selective drive control unit for controlling the current flowing through the wiring 12 which functions as the aforementioned metal coil, and for controlling the MEMS mirror 100 to be driven, and a voltage control unit for adjusting the control voltage applied to the control piezoelectric element 14 in the driven MEMS mirror 100.

[0059] Based on information such as the drive voltage and natural frequency of each MEMS mirror 100 stored in the memory unit, the control unit determines which MEMS mirror 100 to drive among the MEMS mirror array 150, and how to apply the control voltage to the control piezoelectric element 14 in the MEMS mirror 100 to be driven. Based on these decisions, the control unit controls the multiple MEMS mirrors 100.

[0060] This configuration makes it possible to align the natural frequencies of multiple MEMS mirrors in a MEMS mirror array, or to adjust the natural frequencies of some of the MEMS mirrors, allowing for efficient driving of individual MEMS mirrors when multiple MEMS mirrors are driven synchronously. [Explanation of Symbols]

[0061] 10 Frame section 10a Mirror 10A flat plate 10B Shaft 10C beam part 12, 16, 16A, 16B wiring 14, 14A, 14B Control piezoelectric elements 14a electrode 14b Piezoelectric film 14c electrode 18 grooves 20 Arrows 100, 100A, 100B, 100C, 100D MEMS mirrors 110 base 120 Drive control unit 150 MEMS mirror array 200 MEMS Mirror Array System

Claims

1. A flat plate that can be displaced in the direction of film thickness, A frame portion that is spaced apart from the flat plate and surrounds the flat plate, The flat plate and the frame portion are connected, and the support portion has a smaller film thickness than the frame portion, The aforementioned support portion is A beam section in the shape of a cantilevered beam, with both ends connected to the frame section, It has a shaft portion in the shape of a cantilever beam, with one end connected to the flat plate and the other end connected to the beam portion, The system further comprises a control piezoelectric element arranged across the shaft portion and the beam portion, A MEMS mirror that adjusts the spring constant of a support portion by the deformation of the support portion resulting from the deformation of the control piezoelectric element when a control voltage is applied to the control piezoelectric element.

2. The MEMS mirror according to claim 1, wherein the support portion is made of the same material as the flat plate.

3. The MEMS mirror according to claim 1 or 2, wherein the support portion is made of the same material as the frame portion.

4. The MEMS mirror according to any one of claims 1 to 3, wherein the material of the flat plate and the support portion includes silicon.

5. A MEMS mirror array having a plurality of MEMS mirrors according to any one of claims 1 to 4 on a base, A MEMS mirror array system comprising: a drive control unit that controls the control voltage applied to each of the control piezoelectric elements of a plurality of MEMS mirrors.

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