Actuator device, and method for manufacturing actuator device

Abstract

To provide an actuator device capable of realizing highly efficient and stable operation, and to provide a manufacturing method of such an actuator device.SOLUTION: An actuator device includes: a support unit; a first movable unit; a second movable unit; a first connection unit for mutually connecting the first movable unit and the second movable unit; and a second connection unit for mutually connecting the second movable unit and the support unit. The second connection unit mutually connects the second movable unit and the support unit such that the second movable unit is rockable around a second axis crossing a first axis. Two natural angular frequencies ω1,ω2 (herein, ω1<ω2) for vibration of the first movable unit and the second movable unit around the first axis satisfy one of the following expressions (1) and (2) but do not satisfy the other.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] One aspect of the present disclosure relates to an actuator device and a method for manufacturing the actuator device. [Background technology]

[0002] As a MEMS (Micro Electro Mechanical Systems) device, an actuator device is known that includes a support part, a first movable part, a second movable part surrounding the first movable part, a pair of first connecting parts connecting the first movable part and the second movable part to each other on the first axis, and a pair of second connecting parts connecting the second movable part and the support part to each other on the first axis (see, for example, Patent Document 1). In the actuator device described in Patent Document 1, a light reflecting part is provided on the first movable part, and the second movable part rotates about the first axis by application of an AC voltage, which causes the first movable part to rotate about the first axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-99760 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the actuator device as described above, from the viewpoint of high efficiency, it is preferable that the ratio of the deflection angle of the first movable part to the deflection angle of the second movable part is large. Furthermore, the actuator device as described above is required to operate stably.

[0005] An object of one aspect of the present disclosure is to provide an actuator device capable of achieving highly efficient and stable operation, and a method for manufacturing such an actuator device. [Means for solving the problem]

[0006] An actuator device according to one aspect of the present disclosure includes a support portion, a first movable portion, a frame-shaped second movable portion surrounding the first movable portion, a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion can swing around a first axis, a second connecting portion connecting the second movable portion and the support portion to each other so that the first movable portion can swing around the first axis by vibrating the second movable portion, and a drive portion that applies a driving force to the second movable portion, wherein two natural angular frequencies ω1, ω2 (where ω1<ω2) for the vibration of the first movable portion and the second movable portion around the first axis satisfy one of the following first formula (1) and second formula (2), but do not satisfy the other.

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[0007] An actuator device according to one aspect of the present disclosure includes a support portion, a first movable portion, a frame-shaped second movable portion surrounding the first movable portion, a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion can swing around a first axis, a second connecting portion connecting the second movable portion and the support portion to each other, and a drive portion provided on at least one of the first movable portion and the first connecting portion and applying a drive force to the first movable portion, wherein two natural angular frequencies ω1, ω2 (where ω1<ω2) for vibration of the first movable portion and the second movable portion about the first axis satisfy one of the following first formula (3) and second formula (4), but do not satisfy the other.

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[0008] In these actuator devices, when the two natural angular frequencies ω1 and ω2 satisfy the first formula but do not satisfy the second formula, the ratio of the swing angle of the first movable part to the swing angle of the second movable part (hereinafter referred to as the "amplitude ratio") can be set to 5 or more by swinging the first movable part and the second movable part at the natural angular frequency ω1. On the other hand, when the two natural angular frequencies ω1 and ω2 satisfy the second formula but do not satisfy the first formula, the amplitude ratio can be set to 5 or more by swinging the first movable part and the second movable part at the natural angular frequency ω2. Therefore, in either case, a large amplitude ratio can be ensured, and the operation can be made highly efficient. Furthermore, since only one of the first formula and the second formula is satisfied and the other is not satisfied, a large difference between the natural angular frequencies ω1 and ω2 can be ensured, and unnecessary resonant responses can be suppressed to stabilize the operation. Therefore, these actuator devices can realize highly efficient and stable operation.

[0009] The second connecting portion may connect the second movable portion and the support portion to each other so that the second movable portion can swing about a second axis that intersects with the first axis. In this case, the second movable portion can swing about the second axis together with the first movable portion.

[0010] The two natural angular frequencies may satisfy the first formula but not the second formula, and the torsional spring constant of the second connection part about the first axis may be greater than the torsional spring constant of the first connection part about the first axis, in which case an even greater amplitude ratio can be ensured.

[0011] The total length of the second connecting portion may be shorter than the total length of the first connecting portion. In this case, the torsional spring constant of the second connecting portion can be suitably larger than the torsional spring constant of the first connecting portion. Furthermore, by increasing the torsional spring constant of the second connecting portion by shortening the length rather than increasing the cross-sectional area of ​​the second connecting portion, it is possible to ensure a large amplitude ratio while miniaturizing the actuator device.

[0012] The second connecting portion may have a plurality of members each connecting the second movable portion and the support portion to each other, and the plurality of members may be arranged side by side along a direction intersecting the first axis. In this case, the torsional spring constant of the second connecting portion can be more suitably made larger than the torsional spring constant of the first connecting portion.

[0013] The plurality of members may include a first member disposed on the first axis and a pair of second members disposed to sandwich the first member therebetween. In this case, the torsional spring constant of the second connecting portion can be more suitably made larger than the torsional spring constant of the first connecting portion.

[0014] The actuator device according to one aspect of the present disclosure may further include a wiring extending from the second movable part to the support part via the second connecting part, and the wiring may be arranged to pass through the first member. In this case, since the wiring is arranged to pass through the first member which is subjected to a smaller stress when the second movable part vibrates than the second member, deterioration of the wiring in the second connecting part can be suppressed.

[0015] The two natural angular frequencies may satisfy the second formula but not the first formula, and the torsional spring constant of the second connection part about the first axis may be smaller than the torsional spring constant of the first connection part about the first axis, in which case an even larger amplitude ratio can be ensured.

[0016] The overall length of the second connecting portion may be longer than the overall length of the first connecting portion, in which case the torsional spring constant of the second connecting portion can be suitably smaller than the torsional spring constant of the first connecting portion.

[0017] The second connecting portion may extend in a meandering manner. In this case, the torsional spring constant of the second connecting portion can be more suitably smaller than the torsional spring constant of the first connecting portion. Furthermore, since the second connecting portion extends in a meandering manner, impact resistance can be improved compared to, for example, a case in which the second connecting portion extends linearly.

[0018] The support portion, the first movable portion, the second movable portion, the first connecting portion and the second connecting portion may be formed of a semiconductor substrate. An actuator device configured in this manner can also achieve highly efficient and stable operation.

[0019] An actuator device according to one aspect of the present disclosure further includes a sensing coil provided in the first movable part, and a wiring connected to the sensing coil and extending to the second movable part via the first connecting part, the first connecting part being made of a semiconductor material, and a portion of the wiring located on the first connecting part may be made of a diffusion region in which impurities are diffused into the semiconductor material. In this case, a relatively large stress acts on the portion of the wiring located on the first connecting part when the first movable part swings, but since the portion is made of the diffusion region, deterioration of the wiring in the first connecting part can be suppressed.

[0020] The diffusion region may extend from the first connecting portion to the first movable portion and the second movable portion, and the width of the diffusion region in the first movable portion and the second movable portion may be wider than the width of the diffusion region in the first connecting portion. In this case, the resistance of the wiring can be reduced.

[0021] The portion of the wiring located on the first movable part and the portion located on the second movable part may be made of a metal material, and the width of the contact portion between the diffusion region and each of the portion located on the first movable part and the portion located on the second movable part may be wider than the width of the first connecting part. In this case, the resistance of the wiring can be further reduced. Furthermore, even if misalignment occurs during manufacturing, the diffusion region can be reliably electrically connected to each of the portion located on the first movable part and the portion located on the second movable part.

[0022] A manufacturing method for an actuator device according to one aspect of the present disclosure includes an actuator device including a support portion, a first movable portion, a frame-shaped second movable portion surrounding the first movable portion, a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion can oscillate around the first axis, a second connecting portion connecting the second movable portion and the support portion to each other so that the first movable portion can oscillate around the first axis by vibrating the second movable portion, and a driving portion that applies a driving force to the second movable portion, wherein the actuator device is manufactured such that two natural angular frequencies ω1, ω2 (where ω1<ω2) for vibration of the first movable portion and the second movable portion about the first axis satisfy one of the following equations (5) and (6), but do not satisfy the other.

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[0023] A manufacturing method for an actuator device according to one aspect of the present disclosure is a manufacturing method for an actuator device including a support portion, a first movable portion, a frame-shaped second movable portion surrounding the first movable portion, a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion can swing around a first axis, a second connecting portion connecting the second movable portion and the support portion to each other, and a drive portion provided on at least one of the first movable portion and the first connecting portion and applying a driving force to the first movable portion, wherein the actuator device is manufactured such that two natural angular frequencies ω1, ω2 (where ω1<ω2) for vibration of the first movable portion and the second movable portion about the first axis satisfy one of the following equations (7) and (8), but do not satisfy the other.

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[0024] According to the actuator device manufactured by these manufacturing methods, it is possible to realize highly efficient and stable operation for the reasons described above. Effect of the Invention

[0025] According to one aspect of the present disclosure, it is possible to provide an actuator device capable of achieving highly efficient and stable operation, and a method for manufacturing such an actuator device. [Brief description of the drawings]

[0026] [Figure 1] 1 is a plan view of a mirror device according to a first embodiment. [Diagram 2] FIG. 11 is a plan view of a mirror device according to a second embodiment. [Diagram 3] FIG. 3 is a partially enlarged view of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] 5(a) and 5(b) are diagrams showing an example of the relationship between the input angular frequency and the swing angle. [Figure 6] Figure 6(a) is a schematic diagram showing an example of the relationship between the swing angles of the first movable part and the second movable part at resonance point A in Figure 5(a), and Figure 6(b) is a schematic diagram showing an example of the relationship between the swing angles of the first movable part and the second movable part at resonance point B in Figure 5(a). [Figure 7] FIG. 7(a) is a schematic plan view of an exemplary mirror device, and FIG. 7(b) is a diagram showing a vibration model of the mirror device of FIG. 7(a). [Figure 8] 8(a) and 8(b) are graphs showing the relationship between the values ​​for the outside drive case. [Figure 9] 9(a) and 9(b) are graphs showing the relationship between the values ​​for the outside drive case. [Figure 10] 10(a) and 10(b) are graphs showing the relationship between the values ​​for the inside drive case. [Figure 11] FIG. 11 is a plan view of a mirror device according to a first modified example. [Figure 12] FIG. 11 is a plan view of a mirror device according to a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are designated by the same reference numerals, and duplicated description will be omitted. [First embodiment]

[0028] 1, the mirror device 1A of the first embodiment includes a support section 2, a first movable section 3, a second movable section 4, a pair of first connecting sections 5 and 6, a pair of second connecting sections 7 and 8, and a magnetic field generating section 9. The support section 2, the first movable section 3, the second movable section 4, the first connecting sections 5 and 6, and the second connecting sections 7 and 8 are integrally formed by a semiconductor substrate such as an SOI (Silicon on Insulator) substrate. In other words, the mirror device 1A is configured as a MEMS device.

[0029] In the mirror device 1A, a first movable part 3 having a mirror surface (optical surface) 10 is swung around an X-axis (first axis) and a Y-axis (second axis perpendicular to the first axis) that are perpendicular to each other. The mirror device 1A can be used, for example, in an optical switch for optical communication, an optical scanner, etc. The magnetic field generating part 9 is constituted, for example, by a permanent magnet having a Halbach array.

[0030] The support unit 2 has, for example, a rectangular outer shape in a plan view and is formed in a frame shape. The support unit 2 is disposed on one side of the magnetic field generating unit 9 in a direction perpendicular to the X-axis and Y-axis. The first movable unit 3 is disposed inside the support unit 2 and spaced apart from the magnetic field generating unit 9. Note that "plan view" refers to a view seen from a direction perpendicular to the X-axis and Y-axis, in other words, a view seen from a direction perpendicular to the plane on which the support unit 2, the first movable unit 3, the second movable unit 4, etc. are disposed.

[0031] The first movable part 3 has a main body part 3a and a frame part 3b surrounding the main body part 3a. The main body part 3a is formed, for example, in an elliptical shape in a plan view. A circular mirror surface 10 is provided on the surface of the main body part 3a opposite to the magnetic field generating part 9. The mirror surface 10 is formed of a reflective film made of, for example, aluminum, an aluminum alloy, silver, a silver alloy, gold, a dielectric multilayer film, or the like. The frame part 3b has, for example, a rectangular outer shape in a plan view and is formed in a frame shape. The main body part 3a is connected to the frame part 3b on both sides on the Y axis.

[0032] The second movable part 4 has, for example, an octagonal outer shape in a plan view and is formed in a frame shape. The second movable part 4 is disposed inside the support part 2 so as to surround the first movable part 3 while being separated from the magnetic field generating part 9.

[0033] The first connecting parts 5, 6 are disposed on both sides of the first movable part 3 on the X-axis. Each of the first connecting parts 5, 6 connects the first movable part 3 and the second movable part 4 to each other on the X-axis so that the first movable part 3 can swing around the X-axis (with the X-axis as the center line). Each of the first connecting parts 5, 6 is torsionally deformed around the X-axis when the first movable part 3 swings around the X-axis. Each of the first connecting parts 5, 6 extends linearly along the X-axis, for example. Each of the first connecting parts 5, 6 is formed, for example, in a plate shape extending along a plane perpendicular to the X-axis and the Y-axis.

[0034] The first connecting portion 5 has a linear portion 5a that extends along the X-axis and has a constant width, and a pair of widened portions 5b connected to both ends of the linear portion 5a. In a plan view, the width of one of the widened portions 5b increases as it approaches the first movable portion 3, and the width of the other widened portion 5b increases as it approaches the second movable portion 4. A pair of edges of each widened portion 5b are curved so as to be convex toward each other.

[0035] The first connecting portion 6 has a linear portion 6a that extends along the X-axis and has a constant width, and a pair of widened portions 6b connected to both ends of the linear portion 6a. In a plan view, the width of one of the widened portions 6b increases as it approaches the first movable portion 3, and the width of the other widened portion 6b increases as it approaches the second movable portion 4. A pair of edges of each widened portion 6b are curved so as to be convex toward each other.

[0036] The second connecting parts 7, 8 are disposed on both sides of the second movable part 4 on the Y axis. Each of the second connecting parts 7, 8 connects the second movable part 4 and the support part 2 to each other on the Y axis so that the second movable part 4 can swing around the Y axis (with the Y axis as the center line). Each of the second connecting parts 7, 8 is twisted and deformed around the Y axis when the second movable part 4 swings around the Y axis. Each of the second connecting parts 7, 8 extends in a meandering manner in a plan view. Each of the second connecting parts 7, 8 has a plurality of linear parts 11a and a plurality of folded parts 11b. The linear parts 11a each extend along the Y axis direction and are arranged side by side in the X axis direction. The folded parts 11b alternately connect both ends of adjacent linear parts 11a.

[0037] The torsional spring constant of each of the second connecting parts 7, 8 about the X axis is smaller than the torsional spring constant of each of the first connecting parts 5, 6 about the X axis. The torsional spring constant of each of the first connecting parts 5, 6 about the X axis is the ratio of the torsional moment about the X axis acting on each of the first connecting parts 5, 6 to the torsion angle of each of the first connecting parts 5, 6 about the X axis. The torsional spring constant of each of the second connecting parts 7, 8 about the X axis is the ratio of the torsional moment about the X axis acting on each of the second connecting parts 7, 8 to the torsion angle of each of the second connecting parts 7, 8 about the X axis.

[0038] The total length of each of the second connecting portions 7, 8 is longer than the total length of each of the first connecting portions 5, 6. The total length of each of the first connecting portions 5, 6 is the total length along the extension direction of each of the first connecting portions 5, 6 (in this example, the direction along the X-axis). The total length of the second connecting portion 7 is the total length along the extension direction of the second connecting portion 7, and in this example, is the total length obtained by adding up the lengths of each portion including each straight portion 11a and each folded portion 11b. The same applies to the total length of the second connecting portion 8.

[0039] The mirror device 1A further includes coils (driving coils) 21, 22, a plurality of wirings 12, 13, 14, 15, and a plurality of electrode pads 31, 32, 33, 34. The coil 21 is embedded in, for example, the frame portion 3b of the first movable portion 3, and extends in a spiral shape in a planar view. The coil 22 is embedded in, for example, the second movable portion 4, and extends in a spiral shape in a planar view. Each of the coils 21, 22 is made of a metal material such as copper. In FIG. 1, the arrangement areas of the coils 21, 22 are indicated by hatching.

[0040] A plurality of electrode pads 31, 32, 33, 34 are provided on the support 2 and exposed to the outside from the insulating layer 23. The insulating layer 23 is integrally formed so as to cover the surfaces (surfaces opposite to the magnetic field generating unit 9) of the support 2, the first movable part 3, the second movable part 4, the first connecting parts 5, 6, and the second connecting parts 7, 8. The insulating layer 23 is made of, for example, silicon dioxide, silicon nitride, or the like.

[0041] The wiring 12 electrically connects one end of the coil 21 to the electrode pad 31. The wiring 12 extends from one end of the coil 21 to the electrode pad 31 via the first connecting portion 5, the second movable portion 4, and the second connecting portion 7. The wiring 13 electrically connects the other end of the coil 21 to the electrode pad 32. The wiring 13 extends from the other end of the coil 21 to the electrode pad 32 via the first connecting portion 6, the second movable portion 4, and the second connecting portion 8. Of the wirings 12 and 13, the portions 12a and 13a passing through the first connecting portions 5 and 6 are made of a metal material such as tungsten. The other portions of the wirings 12 and 13 are made of a metal material such as aluminum, an aluminum-based alloy, and copper. In FIG. 1, the portions 12a and 13a are indicated by hatching.

[0042] The wiring 14 electrically connects one end of the coil 22 to the electrode pad 33. The wiring 14 extends from one end of the coil 22 to the electrode pad 33 via the second connecting portion 7. The wiring 15 electrically connects the other end of the coil 22 to the electrode pad 34. The wiring 15 extends from the other end of the coil 22 to the electrode pad 34 via the second connecting portion 8.

[0043] In the mirror device 1A configured as above, when a drive signal for linear operation is input to the coil 22 via the electrode pads 33, 34 and the wiring 14, 15, a Lorentz force acts on the coil 22 due to interaction with the magnetic field generated by the magnetic field generating unit 9. By utilizing the balance between the Lorentz force and the elastic forces of the second connecting units 7, 8, the mirror surface 10 (first movable unit 3) can be linearly moved together with the second movable unit 4 around the Y axis.

[0044] On the other hand, when a drive signal for resonant operation is input to the coil 21 via the electrode pads 31, 32 and the wirings 12, 13, a Lorentz force acts on the coil 21 due to interaction with the magnetic field generated by the magnetic field generating unit 9. In addition to the Lorentz force, the mirror surface 10 (first movable part 3) can be made to resonate around the X-axis by utilizing the resonance of the first movable part 3 at the resonant frequency. That is, in the mirror device 1A, the coil 21 and the magnetic field generating unit 9 constitute a drive unit that directly applies a drive force (Lorentz force) to the first movable part 3, and the coil 22 and the magnetic field generating unit 9 constitute a drive unit that directly applies a drive force (Lorentz force) to the second movable part 4. [Second embodiment]

[0045] In the mirror device 1A of the first embodiment, the first movable part 3 is swung around each of the X-axis and the Y-axis, but in the mirror device 1B of the second embodiment shown in FIG. 2, the first movable part 3 is swung only around the X-axis. In the mirror device 1B, the main body 3a of the first movable part 3 is formed in a circular shape in a plan view. The main body 3a is connected to the frame part 3b on both sides on the X-axis and on both sides on the Y-axis. The second movable part 4 has a rectangular outer shape in a plan view.

[0046] The second connecting parts 7, 8 are disposed on both sides of the second movable part 4 on the X-axis. The second connecting parts 7, 8 connect the second movable part 4 and the support part 2 to each other on the X-axis so that the first movable part 3 can swing around the X-axis by vibrating the second movable part 4. Each of the second connecting parts 7, 8 is torsionally deformed around the X-axis when the second movable part 4 vibrates.

[0047] The mirror device 1B does not include the coil 21, the wirings 12, 13, and the electrode pads 31, 32, but includes the coil 22, a coil (electromotive force monitor coil, sensing coil) 24, a plurality of wirings 14, 15, 16, 17, and a plurality of electrode pads 33, 34, 35, 36. The coil 24 is embedded in, for example, the frame portion 3b of the first movable portion 3, and extends in a spiral shape in a plan view. The coil 24 is made of, for example, a metal material such as copper.

[0048] The wiring 16 electrically connects one end of the coil 24 to the electrode pad 35. The wiring 17 extends from one end of the coil 24 to the electrode pad 35 via the first connecting portion 5, the second movable portion 4, and the second connecting portion 7. The wiring 17 electrically connects the other end of the coil 24 to the electrode pad 36. The wiring 17 extends from the other end of the coil 24 to the electrode pad 36 via the first connecting portion 6, the second movable portion 4, and the second connecting portion 8.

[0049] In the mirror device 1B, when a drive signal for resonant operation is input to the coil 22 via the electrode pads 33, 34 and the wirings 14, 15, a Lorentz force acts on the coil 22 due to interaction with the magnetic field generated by the magnetic field generating unit 9. In addition to the Lorentz force, the mirror surface 10 (first movable part 3) can be made to resonate around the X-axis by utilizing the resonance of the first movable part 3 at the resonant frequency. Specifically, when a drive signal of a frequency equal to the resonant frequency of the first movable part 3 around the X-axis is input to the coil 22, the second movable part 4 vibrates slightly around the X-axis at that frequency. This vibration is transmitted to the first movable part 3 via the first connecting parts 5, 6, and the first movable part 3 can be swung around the X-axis at that frequency.

[0050] Furthermore, in the mirror device 1B, while the first movable part 3 is in operation, an electromotive force is generated in the coil 24 due to an interaction with the magnetic field generated by the magnetic field generating unit 9. Therefore, by monitoring the signals output from the electrode pads 35, 36 via the wirings 16, 17, it is possible to grasp the deflection angle of the first movable part 3, i.e., the deflection angle of the mirror surface 10. In this way, the coil 24 functions as an electromotive force monitoring coil.

[0051] Next, the configuration of each part of the mirror device 1B will be further described with reference to Figures 2 and 3. Below, the structure around the first connecting part 5 and the second connecting part 7 will be described, but the first connecting part 6 and the second connecting part 8 are also configured in the same way.

[0052] The second connecting portion 7 has a first member 7a and a pair of second members 7b. The first member 7a and the pair of second members 7b each extend along the X-axis and connect the second movable portion 4 and the support portion 2 to each other. The first member 7a and the pair of second members 7b are arranged, for example, side by side along a direction parallel to the Y-axis. The first member 7a is arranged on the X-axis, and the pair of second members 7b are arranged so as to sandwich the first member 7a between them. The first member 7a and the pair of second members 7b are arranged, for example, side by side at equal intervals so as to be close to each other. The first member 7a and the pair of second members 7b are formed, for example, in the same shape as each other. Each second member 7b functions as a vibration suppressing portion that suppresses vibration of the second movable portion 4 around the X-axis.

[0053] The support portion 2 is provided with a recess 2a located on the X-axis, and the first member 7a and the pair of second members 7b are connected to the support portion 2 at the recess 2a. This makes it possible to reduce the size of the mirror device 1B while ensuring the lengths of the first member 7a and the pair of second members 7b.

[0054] The torsional spring constant of the second connecting portion 7 around the X-axis is smaller than the torsional spring constant of the first connecting portion 5 around the X-axis. The torsional spring constant of the second connecting portion 7 around the X-axis is the torsional spring constant around the X-axis for the entire second connecting portion 7 composed of the first member 7a and the pair of second members 7b. The total length of the second connecting portion 7 is shorter than the total length of the first connecting portion 5. For example, the total length of the second connecting portion 7 is shorter than 1 / 2 the total length of the first connecting portion 5. In this example, the total length of the second connecting portion 7 is the total length obtained by adding up the lengths of the first member 7a and the pair of second members 7b. In this example, the lengths of the first member 7a and the pair of second members 7b are equal to each other.

[0055] The portion of the wiring 16 located on the first coupling portion 5 is configured by a diffusion region 41 in which impurities are diffused into a semiconductor material. The diffusion region 41 is formed, for example, by diffusing n-type impurities into the surface of a p-type silicon substrate. The wiring 16 further has an inner portion 16a that electrically connects one end 41a of the diffusion region 41 to the coil 24, and an outer portion 16b that electrically connects the other end 41b of the diffusion region 41 to the coil 24.

[0056] The diffusion region 41 extends from the first connecting portion 5 to the first movable portion 3, and is connected to the inner portion 16a on the first movable portion 3. The diffusion region 41 also extends from the first connecting portion 5 to the second movable portion 4, and is connected to the outer portion 16b on the second movable portion 4. The outer portion 16b extends to pass through the first member 7a of the second connecting portion 7 and is connected to the electrode pad 35. Similarly, the wiring 14 extending from the coil 22 extends to pass through the first member 7a of the second connecting portion 7 and is connected to the electrode pad 33.

[0057] The width of the end 41a is wider as it approaches the coil 24, and the width of the end 41b is wider as it approaches the coil 22. The ends 41a and 41b each have an outer shape that follows the pair of widened portions 5b of the first connecting portion 5. The width W1 of the end 41a and the width W2 of the end 41b are each wider than the width W3 of the first connecting portion 5. That is, each of the widths W1 and W2 is wider than the width of the diffusion region 41 on the first connecting portion 5. The width of each portion of the diffusion region 41 is the maximum width in a plan view, and is the width in a direction perpendicular to the extension direction of the diffusion region 41 (in this example, the direction parallel to the Y axis). The width of the first connecting portion 5 is the minimum width in a plan view, and is, for example, the width of the linear portion 5a in a direction perpendicular to the extension direction of the first connecting portion 5 (in this example, the direction parallel to the Y axis). The first connecting portion 5 is a portion that undergoes torsional deformation around the X-axis when the first movable portion 3 swings around the X-axis, and in the mirror device 1B, the first connecting portion 5 includes a pair of widening portions 5b.

[0058] 4, the first movable part 3 is provided with a groove 42a having a shape corresponding to the coil 24, and the second movable part 4 is provided with a groove 42b having a shape corresponding to the coil 22. Insulating layers 43 and 44 are provided on the inner surfaces of the grooves 42a and 42b, and insulating layers 45 and 46 are provided on the insulating layer 44. The coil 24 is disposed in the groove 42 with the insulating layers 43 and 44 interposed therebetween.

[0059] Each of the insulating layers 43-46 is made of, for example, silicon dioxide, silicon nitride, etc. The inner portion 16a and the outer portion 16b of the wiring 16 are disposed on the insulating layer 45. The inner portion 16a and the outer portion 16b are formed to enter an opening 47 penetrating the insulating layers 43-45, and are connected to the diffusion region 41 at the opening 47.

[0060] The inner portion 16a and the outer portion 16b each have a first layer 48 and a second layer 49 disposed on the first layer 48. The first layer 48 functions as a contact layer in contact with the diffusion region 41, and also functions as a barrier layer that prevents the diffusion of metal elements contained in the second layer 49 into the silicon substrate. The first layer 48 is made of a metal material such as tungsten, titanium nitride, molybdenum, tantalum, or tantalum nitride. The second layer 49 is made of a metal material such as an aluminum alloy or copper.

[0061] Each of width W4 of a contact portion between diffusion region 41 and inner portion 16a and width W5 of a contact portion between diffusion region 41 and outer portion 16b is wider than width W3 of first connecting portion 5. These widths of the contact portions are the widths in a direction perpendicular to the extension direction of first connecting portion 5 in a plan view (in this example, a direction parallel to the Y-axis). [Mirror device manufacturing method]

[0062] Next, a manufacturing method (design method) of the mirror devices 1A and 1B described above will be described. Fig. 5(a) is a diagram showing an example of the relationship between the angular frequency of the drive signal and the deflection angle of the first movable part 3 and the second movable part 4 about the X-axis, and Fig. 5(b) is a diagram showing another example of the relationship. In Figs. 5(a) and 5(b), the deflection angle of the first movable part 3 is indicated by a solid line, and the deflection angle of the second movable part 4 is indicated by a dashed line.

[0063] As shown in FIG. 5(a) and FIG. 5(b), the two-degree-of-freedom vibration system in the mirror device 1A, 1B, which is constituted by the support part 2, the first movable part 3, the second movable part 4, the first connecting parts 5, 6, and the second connecting parts 7, 8, has two resonance points A, B for vibration around the X-axis. However, in this two-degree-of-freedom vibration system, only vibration around the X-axis is considered, and vibration around the Y-axis is not considered. The natural angular frequency ω1 at the resonance point A and the natural angular frequency ω2 at the resonance point B (where ω1<ω2) are natural angular frequencies for the vibration of the first movable part 3 and the second movable part 4 around the X-axis. The resonance point A can be used when the mirror surface 10 is operated at a relatively small frequency. The resonance point B can be used when the mirror surface 10 is operated at a relatively large frequency.

[0064] The relationship between the swing angles of the first movable part 3 and the second movable part 4 when the mirror surface 10 is operated at resonance point A in Figure 5(a) can be shown as shown in Figure 6(a), and the relationship between the swing angles of the first movable part 3 and the second movable part 4 when the mirror surface 10 is operated at resonance point B in Figure 5(a) can be shown as shown in Figure 6(b).

[0065] As shown in FIG. 6(a), when the mirror surface 10 is operated at the resonance point A in FIG. 5(a), the first movable part 3 and the second movable part 4 rotate to the same extent, and the difference in the deflection angle between the first movable part 3 and the second movable part 4 becomes small. That is, the first connecting parts 5, 6 hardly undergo torsional deformation. As shown in FIG. 6(b), when the mirror surface 10 is operated at the resonance point B in FIG. 5(a), the second movable part 4 hardly rotates, while the first movable part 3 rotates, and the difference in the deflection angle between the first movable part 3 and the second movable part 4 becomes large. That is, the first connecting parts 5, 6 efficiently undergo torsional deformation.

[0066] Contrary to the example of FIG. 5(a), in the example of FIG. 5(b), when the mirror surface 10 is operated at the resonance point A, the second movable part 4 hardly rotates while the first movable part 3 rotates, and when the mirror surface 10 is operated at the resonance point B, the first movable part 3 and the second movable part 4 rotate to the same extent. From the viewpoint of high efficiency, when the mirror surface 10 is operated at either the resonance point A or B, it is preferable that the deflection angle of the first movable part 3 is large while the deflection angle of the second movable part 4 is small. In other words, it is preferable to ensure a large ratio of the deflection angle of the first movable part 3 to the deflection angle of the second movable part 4 (hereinafter referred to as "amplitude ratio"). Below, a manufacturing method of the mirror devices 1A and 1B for ensuring a large amplitude ratio will be described. [In the case of external drive]

[0067] First, a case where the first movable part 3 is resonated by applying a driving force to the second movable part 4 as in the mirror device 1B (case of external drive) will be described. FIG. 7(a) is a schematic plan view of an exemplary mirror device 1C, and FIG. 7(b) is a diagram showing a vibration model of the mirror device 1C. The vibration model shown in FIG. 7(b) makes it possible to model the vibration of the first movable part 3 and the second movable part 4 around the X-axis. The equations of motion for the vibration of the first movable part 3 and the second movable part 4 around the X-axis are expressed by the following formulas (9) and (10).

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number

number

number

[0068] From the formulas (9) and (10), the swing angle θ of the first movable part 3 is i , and the swing angle θ of the second movable part 4 o is obtained as expressed by the following equations (13) and (14).

number

number

number

number

number

number

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[0069] At this time, the amplitude ratio θ i / θ o is expressed by the following equation (20). o is, for example, 0.01 or less, and is much smaller than 1.

number

[0070] Therefore, the condition for making the amplitude ratio 5 or more is expressed by the following equation (21).

number

[0071] When the mirror surface 10 is operated at the natural angular frequency ω1 at the resonance point A (i.e., when ω=ω1), 1-(ω1 / ω ii ) 2 Since is greater than zero, the condition for making the amplitude ratio 5 or more is expressed by the following equation (22).

number

[0072] When the mirror surface 10 is operated at the natural angular frequency ω2 at the resonance point B (i.e., when ω=ω2), 1-(ω2 / ω ii ) 2 Since is smaller than zero, the condition for making the amplitude ratio 5 or more is expressed by the following equation (23).

number

[0073] In other words, when mirror surface 10 is operated at natural angular frequency ω1, the amplitude ratio can be made 5 or more by designing and manufacturing the mirror device so that equation (22) is satisfied, and when mirror surface 10 is operated at natural angular frequency ω2, the amplitude ratio can be made 5 or more by designing and manufacturing the mirror device so that equation (23) is satisfied.

[0074] 8(a) and 8(b) are graphs showing the relationship between values ​​when the mirror surface 10 is operated at a natural angular frequency ω1 in the case of an outer drive. In FIG. 8(a), 1-(ω1 / ω ii ) 2 and the amplitude ratio θ i / θ o In FIG. 8(b), the relationship between the torsional spring constant k o and the amplitude ratio θ i / θ o As shown in FIG. 8(a), by designing and manufacturing a mirror device so that formula (22) is satisfied, the amplitude ratio can be made 5 or more. As shown in FIG. 8(b), the torsional spring constant k o As the torsional spring constant k increases, the amplitude ratio increases. o By increasing the amplitude ratio, a large amplitude ratio can be ensured.

[0075] 9(a) and 9(b) are graphs showing the relationship between values ​​when the mirror surface 10 is operated at the natural angular frequency ω2 in the case of the outer drive. In FIG. 9(a), (ω2 / ω ii ) 2 -1 and amplitude ratio θ i / θ o In FIG. 9(b), the torsional spring constant k o and the amplitude ratio θ i / θ oAs shown in FIG. 9(a), by designing and manufacturing a mirror device so that formula (23) is satisfied, the amplitude ratio can be made 5 or more. As shown in FIG. 9(b), the torsional spring constant k o As the torsional spring constant k increases, the amplitude ratio decreases. o By reducing the amplitude ratio, a large amplitude ratio can be ensured.

[0076] Here, if the values ​​of the natural angular frequencies ω1 and ω2 are close to each other and the difference between the natural angular frequencies ω1 and ω2 is small, both of the formulas (22) and (23) are satisfied. However, if the difference between the natural angular frequencies ω1 and ω2 is small, for example, when the mirror surface 10 is operated at the natural angular frequency ω1, a resonant response for the natural angular frequency ω2 occurs, and the operation of the mirror surface 10 may become unstable. Therefore, in the manufacturing method of the mirror device of this embodiment, in the case of outer drive, the mirror device is designed and manufactured so that only one of the formulas (22) and (23) is satisfied and the other is not satisfied. This makes it possible to ensure a large difference between the natural angular frequencies ω1 and ω2, and to suppress unnecessary resonant responses and stabilize the operation. This point is common to the case where the mirror surface 10 is operated at either the natural angular frequency ω1 or ω2.

[0077] For example, in the mirror device 1B according to the second embodiment, only formula (22) is satisfied, and formula (23) is not satisfied. Therefore, by operating the mirror surface 10 at the natural angular frequency ω1, the amplitude ratio can be made 5 or more. In addition, a large difference between the natural angular frequencies ω1 and ω2 can be ensured, and unnecessary resonant responses can be suppressed to stabilize the operation. [Inner drive]

[0078] Next, a case where the first movable part 3 is resonated by applying a driving force to the first movable part 3 (inner drive case) as in the mirror device 1A will be described. In this case, the equations of motion for the vibration of the first movable part 3 and the second movable part 4 around the X-axis are expressed by the following formulas (24) and (25).

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[0079] From the formulas (24) and (25), the swing angle θ of the first movable part 3 is i , and the swing angle θ of the second movable part 4 o is obtained as expressed by the following equations (26) and (27).

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[0080] At this time, the amplitude ratio θ i / θ o is expressed by the following equation (30).

number

[0081] Therefore, the condition for making the amplitude ratio 5 or more is expressed by the following equation (31).

number

[0082] When the mirror surface 10 is operated at the natural angular frequency ω1 at the resonance point A (i.e., when ω=ω1), 1-(ω io / ω oo ) 2 +(ω1 / ω oo ) 2 is greater than zero, the condition for making the amplitude ratio 5 or more is given by the following equation (32).

number

[0083] On the other hand, when the mirror surface 10 is operated at the natural angular frequency ω2 at the resonance point B (i.e., when ω=ω2), 1-(ω io / ω oo ) 2 +(ω2 / ω oo ) 2 Since is smaller than zero, the condition for making the amplitude ratio 5 or more is given by the following equation (33).

number

[0084] That is, when mirror surface 10 is operated at natural angular frequency ω1, the amplitude ratio can be made 5 or more by designing and manufacturing the mirror device so that equation (32) is satisfied, and when mirror surface 10 is operated at natural angular frequency ω2, the amplitude ratio can be made 5 or more by designing and manufacturing the mirror device so that equation (33) is satisfied. By designing and manufacturing the mirror device so that only one of equations (32) and (33) is satisfied and the other is not satisfied, a large difference between the natural angular frequencies ω1 and ω2 can be ensured, and unnecessary resonant responses can be suppressed to stabilize operation, just like in the case of outer drive.

[0085] 10(a) and 10(b) are graphs showing the relationship between values ​​for the inner drive. In FIG. 10(a), 4ω io 2 / (ω oo 2 -ω12 ) and amplitude ratio θ i / θ o FIG. 10(b) shows the relationship between the (ω oo 2 -ω2 2 ) / ω io 2 and the amplitude ratio θ i / θ o The relationship is shown.

[0086] As shown in Fig. 10(a), by designing and manufacturing the mirror device so that formula (32) is satisfied, the amplitude ratio can be made 5 or more. In addition, in the case of inner drive, when the mirror surface 10 is operated at the natural angular frequency ω1, the torsional spring constant k o As the torsional spring constant k increases, the amplitude ratio increases. o By increasing the amplitude ratio, a large amplitude ratio can be ensured.

[0087] As shown in FIG. 10(b), by designing and manufacturing the mirror device so that formula (33) is satisfied, the amplitude ratio can be made 5 or more. In addition, in the case of inner drive, when the mirror surface 10 is operated at the natural angular frequency ω2, the torsional spring constant k o As the torsional spring constant k increases, the amplitude ratio decreases. o By reducing the amplitude ratio, a large amplitude ratio can be ensured.

[0088] For example, in the mirror device 1A according to the first embodiment, only formula (33) is satisfied, and formula (32) is not satisfied. Therefore, by operating the mirror surface 10 at the natural angular frequency ω2, the amplitude ratio can be made 5 or more. In addition, a large difference between the natural angular frequencies ω1 and ω2 can be ensured, and unnecessary resonant responses can be suppressed to stabilize the operation. [Action and Effects]

[0089] As described above, in the mirror device 1A, the two natural angular frequencies ω1 and ω2 satisfy only the formula (33) (first formula) and do not satisfy the formula (32) (second formula), so that the first movable part 3 and the second movable part 4 are oscillated at the natural angular frequency ω2, and the amplitude ratio can be set to 5 or more. Therefore, a large amplitude ratio can be ensured, and the operation can be made highly efficient. Furthermore, since only the formula (33) is satisfied, and the formula (32) is not satisfied, a large difference between the natural angular frequencies ω1 and ω2 can be ensured, and the operation can be stabilized by suppressing unnecessary resonant responses. Therefore, according to the mirror device 1A, highly efficient and stable operation can be realized.

[0090] In the mirror device 1B, the two natural angular frequencies ω1 and ω2 satisfy only the formula (22) (first formula) and do not satisfy the formula (23) (second formula), so that the first movable part 3 and the second movable part 4 are oscillated at the natural angular frequency ω1, whereby the amplitude ratio can be set to 5 or more. Therefore, a large amplitude ratio can be ensured, and the operation can be made highly efficient. Furthermore, since only the formula (22) is satisfied, and the formula (23) is not satisfied, a large difference between the natural angular frequencies ω1 and ω2 can be ensured, and unnecessary resonant responses can be suppressed to stabilize the operation. Therefore, according to the mirror device 1B, highly efficient and stable operation can be realized.

[0091] In the mirror device 1A, the second connecting parts 7, 8 connect the second movable part 4 and the support part 2 to each other so that the second movable part 4 can swing around the Y axis. Therefore, the second movable part 4 can swing around the Y axis together with the first movable part 3.

[0092] In the mirror device 1B, the torsional spring constant of each of the second connecting parts 7, 8 about the X axis is greater than the torsional spring constant of each of the first connecting parts 5, 6 about the X axis, so that a larger amplitude ratio can be ensured.

[0093] In the mirror device 1B, the total length of each of the second connecting parts 7, 8 is shorter than the total length of each of the first connecting parts 5, 6. Therefore, the torsional spring constant of the second connecting parts 7, 8 can be suitably made larger than the torsional spring constant of the first connecting parts 5, 6. Furthermore, by increasing the torsional spring constant of the second connecting parts 7, 8 by shortening the length rather than increasing the cross-sectional area of ​​the second connecting parts 7, 8, it is possible to ensure a large amplitude ratio while miniaturizing the mirror device 1B.

[0094] In the mirror device 1B, the first member 7a and the pair of second members 7b (multiple members) are arranged side by side in a direction parallel to the Y axis. Therefore, the torsional spring constant of the second connecting parts 7, 8 can be more suitably made larger than the torsional spring constant of the first connecting parts 5, 6.

[0095] In the mirror device 1B, each of the second connecting parts 7, 8 has a first member 7a arranged on the X-axis and a pair of second members 7b arranged to sandwich the first member 7a between them. Therefore, the torsional spring constant of the second connecting parts 7, 8 can be more suitably made larger than the torsional spring constant of the first connecting parts 5, 6.

[0096] In the mirror device 1B, the wirings 14, 16 are arranged to pass through the first member 7a. Since the wirings 14, 16 are arranged to pass through the first member 7a, which is subjected to a smaller stress when the second movable part 4 vibrates than the second member 7b, deterioration of the wirings 14, 16 in the second connecting part 7 can be suppressed.

[0097] In the mirror device 1A, the torsional spring constant of each of the second connecting parts 7, 8 about the X axis is smaller than the torsional spring constant of each of the first connecting parts 5, 6 about the X axis, so that a larger amplitude ratio can be ensured.

[0098] In the mirror device 1A, the overall length of each of the second connecting parts 7, 8 is longer than the overall length of each of the first connecting parts 5, 6. Therefore, the torsional spring constant of the second connecting parts 7, 8 can be suitably made smaller than the torsional spring constant of the first connecting parts 5, 6.

[0099] In the mirror device 1A, the second connecting parts 7, 8 extend in a meandering manner. Therefore, the torsional spring constant of the second connecting parts 7, 8 can be more suitably set smaller than the torsional spring constant of the first connecting parts 5, 6. Furthermore, since the second connecting parts 7, 8 extend in a meandering manner, impact resistance can be improved compared to, for example, a case in which the second connecting parts 7, 8 extend linearly.

[0100] In the mirror devices 1A and 1B, the support portion 2, the first movable portion 3, the second movable portion 4, the first connecting portions 5 and 6, and the second connecting portions 7 and 8 are made of semiconductor substrates. The mirror devices 1A and 1B thus configured can also achieve highly efficient and stable operation.

[0101] In the mirror device 1B, the portions of the wiring 16 located on the first connecting parts 5 and 6 are formed of diffusion regions 41 in which impurities are diffused into a semiconductor material. A relatively large stress acts on the portions of the wiring 16 located on the first connecting parts 5 and 6 when the first movable part 3 swings, but since the portions are formed of the diffusion regions 41, deterioration of the wiring in the first connecting parts 5 and 6 can be suppressed. That is, when the portions are formed of the diffusion regions 41, metal fatigue, cracks, etc. can be suppressed compared to when the portions are formed of metal, for example, and reliability can be improved. Since the wiring 16 is connected to the coil 24 for electromotive force monitoring, a relatively small current flows through the wiring 16 compared to, for example, a wiring connected to a driving coil. Therefore, it is not necessary to make the wiring 16 extremely low resistance.

[0102] In the mirror device 1B, the width of the diffusion region 41 in the first movable portion 3 and the second movable portion 4 (the width W1 of the end portion 41a and the width W2 of the end portion 41b) is wider than the width of the diffusion region 41 in the first connecting portions 5 and 6. Therefore, the resistance of the wiring 16 can be reduced.

[0103] In the mirror device 1B, the inner portion 16a of the wiring 16 located on the first movable portion 3 and the outer portion 16b of the wiring 16 located on the second movable portion 4 are made of a metal material. The width W4 of the contact portion between the diffusion region 41 and the inner portion 16a and the width W5 of the contact portion between the diffusion region 41 and the outer portion 16b are each wider than the width W3 of each of the first coupling portions 5 and 6. This allows the wiring 16 to have an even lower resistance. Even if misalignment occurs during manufacturing, the diffusion region 41 can be reliably electrically connected to each of the inner portion 16a and the outer portion 16b. [Variations]

[0104] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. In the mirror device 1A of the first embodiment, the first movable part 3 may be resonantly operated by applying a driving force to the second movable part 4. That is, the structure of the mirror device 1A may be used for outer driving. In this case, the first movable part 3 may not be provided with the coil 21, and the second movable part 4 may be provided with a coil for resonant operation of the first movable part 3 in addition to the coil 22. As in the case of the mirror device 1B, the mirror surface 10 can be resonantly operated around the X-axis by utilizing the Lorentz force generated by the interaction between the coil for resonant operation and the magnetic field generated by the magnetic field generating unit 9, as well as the resonance of the first movable part 3 at the resonant frequency. Note that the coil for resonant operation may not be provided, and the coil 22 may be used as a coil for linear operation of the second movable part 4 and for resonant operation of the first movable part 3. Such a mirror device is designed and manufactured so that only the above formula (23) is satisfied, and formula (22) is not satisfied. As a result, by operating the mirror surface 10 at the natural angular frequency ω2, it is possible to make the amplitude ratio equal to or greater than 5. In addition, it is possible to ensure a large difference between the natural angular frequencies ω1 and ω2, thereby suppressing unnecessary resonant responses and stabilizing operation.

[0105] In the mirror device 1B of the second embodiment, the first movable part 3 may be resonantly operated by applying a driving force to the first movable part 3. That is, the structure of the mirror device 1B may be used for inward driving. In this case, the second movable part 4 may not be provided with the coil 22, and the first movable part 3 may be provided with a driving coil instead of or in addition to the coil 24. As in the case of the mirror device 1A, the mirror surface 10 can be resonantly operated around the X-axis by utilizing the Lorentz force generated by the interaction between the driving coil and the magnetic field generated by the magnetic field generating unit 9, as well as the resonance of the first movable part 3 at the resonant frequency. Such a mirror device is designed and manufactured so that only the above formula (32) is satisfied, and formula (33) is not satisfied. As a result, the mirror surface 10 is operated at the natural angular frequency ω1, and the amplitude ratio can be made 5 or more. In addition, the difference between the natural angular frequencies ω1 and ω2 can be secured to be large, and unnecessary resonant responses can be suppressed to stabilize the operation.

[0106] In the mirror devices 1A and 1B, the mirror surface 10 is driven by electromagnetic force, but the mirror surface 10 may be driven by a piezoelectric element or electrostatic force. In this case, other driving elements such as a piezoelectric film or electrostatic comb teeth are provided instead of the coil. In the mirror device 1A, the second connecting parts 7 and 8 may extend along the X-axis and connect the second movable part 4 and the support part 2 to each other on the X-axis. Even in this case, the first movable part 3 can be swung around each of the X-axis and the Y-axis. In the mirror device 1A, the second connecting parts 7 and 8 may connect the second movable part 4 and the support part 2 to each other so that the second movable part 4 can swung around a second axis that intersects with the first axis. In other words, the second axis does not necessarily have to be perpendicular to the first axis. In the mirror device 1B, the second member 7b may extend at an angle to the X-axis. The second member 7b may extend along a direction parallel to the Y-axis to connect the second movable portion 4 and the support portion 2 to each other. In the above-mentioned example, the lower limit of the amplitude ratio is set to 5, but the lower limit may be set to 10. In the mirror device 1B, the coil 24 may be used as a temperature detection coil (sensing coil).

[0107] In the mirror device 1A, the drive unit (coil 21, drive element) for applying a drive force to the first movable part 3 is provided in the first movable part 3, but the drive unit may be provided in the first movable part 3 and / or the first connecting parts 5, 6, for example, and may be provided in each of the first connecting parts 5, 6. In the mirror devices 1A and 1B, the drive unit (coil 22, drive element) for applying a drive force to the second movable part 4 is provided in the second movable part 4, but the drive unit may be provided in the second movable part 4 and / or the second connecting parts 7, 8, for example, and may be provided in each of the second connecting parts 7, 8.

[0108] In the mirror devices 1A and 1B, a first driving element (e.g., a coil) for directly applying a driving force to the first movable part 3 may be provided on the first movable part 3 and / or the first connecting parts 5 and 6, and a second driving element (e.g., a coil) for directly applying a driving force to the second movable part 4 may be provided on the second movable part 4 and / or the second connecting parts 7 and 8. In such a configuration, the mirror surface 10 (first movable part 3) can be resonated around the X-axis using both (cooperation of) the driving force that acts directly on the first movable part 3 by the first driving element and the driving force that acts indirectly on the first movable part 3 by vibrating the second movable part 4 by the second driving element. When this configuration is employed in mirror device 1A, for example, the first movable part 3 is provided with a coil for swinging the first movable part 3 about the X-axis, and the second movable part 4 is provided with a coil for swinging the second movable part 4 about the Y-axis and a coil for swinging the first movable part 3 about the X-axis by vibrating the second movable part 4. When this configuration is employed in mirror device 1B, for example, the first movable part 3 is provided with a coil for swinging the first movable part 3 about the X-axis, and the second movable part 4 is provided with a coil for swinging the first movable part 3 about the X-axis by vibrating the second movable part 4. When this configuration is adopted in the mirror device 1B, the mirror surface 10 (first movable part 3) can be resonated around the X-axis using a driving force acting directly on the first movable part 3 by the first driving element, and the second movable part 4 can be operated around the X-axis using a driving force acting directly on the second movable part 4 by the second driving element (i.e., it can also be applied to inward driving).

[0109] The material and shape of each component are not limited to the above-mentioned materials and shapes, and various materials and shapes can be adopted. The first movable part 3 and the second movable part 4 may have any outer shape such as a substantially circular shape, a substantially elliptical shape, a substantially rectangular shape, or a substantially rhombic shape in a plan view. The frame part 3b may not be provided, and the first connecting parts 5, 6 may be directly connected to the main body part 3a. The first connecting part 5 may not be provided with at least one of the pair of widening parts 5b, and the first connecting part 6 may not be provided with at least one of the pair of widening parts 6b. The first movable part 3 may have an optical surface other than the mirror surface 10, for example, a diffraction grating surface. That is, the actuator device of the present disclosure may be a device for driving other than the mirror surface 10.

[0110] In the mirror device 1D of the first modification shown in FIG. 11, the first movable part 3 is swung around each of the X-axis and Y-axis which are perpendicular to each other. The first movable part 3 is formed in an elliptical shape in a plan view. The first connecting parts 5 and 6 extend linearly along the X-axis. The second connecting parts 7 and 8 extend linearly along the Y-axis. The second movable part 4 has a frame-shaped part 4a surrounding the first movable part 3 and an intermediate part 4b connected to the frame-shaped part 4a.

[0111] The frame-shaped portion 4a has a rectangular outer shape in a plan view. The intermediate portion 4b has, for example, a substantially rectangular outer shape in a plan view and is formed in a frame shape. The intermediate portion 4b has a pair of first portions 4b1 and a pair of second portions 4b2 connected to the pair of first portions 4b1, respectively. The pair of first portions 4b1 extend along a direction parallel to the X-axis and face each other in the Y-axis direction. The pair of second portions 4b2 extend along a direction parallel to the Y-axis and face each other in the X-axis direction. The width of the first portions 4b1 (length in the Y-axis direction) is wider than the width of the second portions 4b2 (length in the X-axis direction). The intermediate portion 4b is disposed inside the frame-shaped portion 4a and is connected to the frame-shaped portion 4a at the first portions 4b1. The intermediate portion 4b is connected to the first connecting portions 5 and 6 at the second portions 4b2.

[0112] In the mirror device 1D, a pair of piezoelectric films 51 are provided as a driving unit for applying a driving force to the first movable portion 3. The pair of piezoelectric films 51 are respectively disposed in a pair of first portions 4b1 of the intermediate portion 4b. Each of the piezoelectric films 51 has, for example, a rectangular shape in a plan view having long sides parallel to the X-axis.

[0113] In the mirror device 1D, when a drive signal is input to the piezoelectric film 51 via an electrode pad and wiring (not shown), the piezoelectric film 51 is flexed and deformed in the longitudinal direction. By controlling the timing of deformation of the pair of piezoelectric films 51, a drive force can be applied to the middle portion 4b (second movable portion 4). For example, the pair of piezoelectric films 51 are flexed and deformed alternately. The rigidity of the middle portion 4b is smaller than the rigidity of the frame-shaped portion 4a, and the middle portion 4b is softer than the frame-shaped portion 4a.

[0114] The driving of the first movable part 3 in the mirror device 1D is an external driving that causes the first movable part 3 to resonate by applying a driving force to the second movable part 4. In the mirror device 1D, similar to the mirror device 1B, when the mirror surface 10 is operated at the first natural angular frequency ω1, the mirror device can be designed and manufactured so that the formula (22) is satisfied, and when the mirror surface 10 is operated at the natural angular frequency ω2, the mirror device can be designed and manufactured so that the formula (23) is satisfied, and the amplitude ratio can be made 5 or more. In addition, by designing and manufacturing the mirror device so that only one of the formulas (22) and (23) is satisfied and the other is not satisfied, a large difference between the natural angular frequencies ω1 and ω2 can be secured, and unnecessary resonant responses can be suppressed to stabilize the operation. The mirror device 1D can also realize highly efficient and stable operation, similar to the mirror device 1B.

[0115] 12 differs from the mirror device 1D in that a piezoelectric film 51 is disposed on the second portion 4b2 of the intermediate portion 4b. Specifically, a pair of piezoelectric films 51 are disposed side by side in a direction parallel to the Y-axis on each of the pair of second portions 4b2. In the mirror device 1E, too, a driving force can be applied to the intermediate portion 4b (second movable portion 4) by controlling the timing of deformation of each piezoelectric film 51. Similarly to the mirror device 1B, the mirror device 1E can also realize highly efficient and stable operation. [Explanation of symbols]

[0116] 1A, 1B, 1C...mirror device (actuator device), 2...support part, 3...first movable part, 4...second movable part, 5, 6...first connecting part, 7, 8...second connecting part, 7a...first member, 7b...second member, 9...magnetic field generating part (driving part), 14, 15, 16, 17...wiring, 16a...inner part, 16b...outer part, 41...diffusion region, 21...coil (driving part), 22...coil (driving part), 24...coil (coil for electromotive force monitor, coil for sensing).

Claims

1. A support portion; A first movable part; A frame-shaped second movable part surrounding the first movable part; a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion is pivotable around a first axis; a second coupling portion coupling the second movable portion and the support portion to each other such that the first movable portion is swingable around the first axis by vibrating the second movable portion; a drive unit that applies a drive force to the second movable unit, the second connecting portion connects the second movable portion and the support portion to each other such that the second movable portion is swingable around a second axis line intersecting the first axis line, Two natural angular frequencies ω for vibration of the first movable part and the second movable part about the first axis １ , ω ２ (However, １ <ω ２ ) is an actuator device that satisfies one of the following first formula (1) and second formula (2) but does not satisfy the other. [0010] [0025] In the above formula, ω ｉｉ = (k ｉ / j ｉ ) １／２ and k ｉ is the torsional spring constant of the first connection portion about the first axis, and j ｉ is the moment of inertia of the first movable part about the first axis.

2. A support portion; A first movable part; A frame-shaped second movable part surrounding the first movable part; a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion is pivotable around a first axis; a second connecting portion connecting the second movable portion and the support portion to each other; a drive unit provided on at least one of the first movable unit and the first connecting unit, and configured to apply a drive force to the first movable unit; the second connecting portion connects the second movable portion and the support portion to each other so that the second movable portion can swing about a second axis line intersecting the first axis line, and two natural angular frequencies ω １ , ω ２ (However, １ <ω ２ ) is an actuator device which satisfies one of the following first formula (3) and second formula (4) but does not satisfy the other. [0030] [0045] In the above formula, ω ｉｏ = (k ｉ / j ｏ ) １／２ and ω ｏｏ = (k ｏ / j ｏ ) １／２ and k ｉ is the torsional spring constant of the first connection portion about the first axis, and k ｏ is the torsional spring constant of the second connection portion about the first axis, and j ｏ is the moment of inertia of the second movable part about the first axis.

3. The two natural angular frequencies satisfy the first formula but do not satisfy the second formula, The actuator device according to claim 1 , wherein a torsional spring constant of the second connecting portion about the first axis is greater than a torsional spring constant of the first connecting portion about the first axis.

4. The two natural angular frequencies satisfy the second formula but do not satisfy the first formula, 3 . The actuator device according to claim 1 , wherein a torsional spring constant of the second connecting portion about the first axis is smaller than a torsional spring constant of the first connecting portion about the first axis.

5. The actuator device according to any one of claims 1 to 4, wherein a total length of the second connecting portion is shorter than a total length of the first connecting portion.

6. The actuator device according to claim 1 , wherein a total length of the second connecting portion is longer than a total length of the first connecting portion.

7. The actuator device according to any one of claims 1 to 6, wherein the second connecting portion extends in a serpentine manner.

8. 8. The actuator device according to claim 1, wherein the support portion, the first movable portion, the second movable portion, the first connecting portion, and the second connecting portion are formed of a semiconductor substrate.

9. The first movable portion has a main body portion provided with an optical surface and a frame portion surrounding the main body portion, The actuator device according to any one of claims 1 to 8, wherein the first connecting portion is connected to the frame portion.

10. a wiring extending from the second movable portion to the support portion via the second connecting portion; The actuator device according to claim 1 , further comprising: an insulating layer provided on the second connecting portion and covering the wiring.

11. The actuator device according to any one of claims 1 to 10, wherein the first movable portion and the second movable portion are not provided with magnets.

12. The actuator device according to any one of claims 1 to 11, wherein the first connecting portion has a widening portion whose width increases as it approaches the second movable portion when viewed from a direction perpendicular to a plane in which the support portion, the first movable portion, and the second movable portion are arranged, and the first connecting portion is connected to the second movable portion at the widening portion.

13. A support portion; A first movable part; A frame-shaped second movable part surrounding the first movable part; a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion is pivotable around a first axis; a second coupling portion coupling the second movable portion and the support portion to each other such that the first movable portion is swingable around the first axis by vibrating the second movable portion; a drive unit that applies a drive force to the second movable unit, a second connecting portion connecting the second movable portion and the support portion to each other such that the second movable portion is swingable around a second axis line intersecting the first axis line, Two natural angular frequencies ω for vibration of the first movable part and the second movable part about the first axis １ , ω ２ (However, １ <ω ２ ) satisfies one of the following formulas (5) and (6), but does not satisfy the other: [0050] [006] In the above formula, ω ｉｉ = (k ｉ / j ｉ ) １／２ and k ｉ is the torsional spring constant of the first connection portion about the first axis, and j ｉ is the moment of inertia of the first movable part about the first axis.

14. A support portion; A first movable part; A frame-shaped second movable part surrounding the first movable part; a first connecting portion connecting the first movable portion and the second movable portion to each other so that the first movable portion is pivotable around a first axis; a second connecting portion connecting the second movable portion and the support portion to each other; a drive unit provided on at least one of the first movable unit and the first connecting unit, and configured to apply a drive force to the first movable unit; a second connecting portion connecting the second movable portion and the support portion to each other such that the second movable portion is swingable around a second axis line intersecting the first axis line, Two natural angular frequencies ω for vibration of the first movable part and the second movable part about the first axis １ , ω ２ (However, １ <ω ２ ) satisfies one of the following formulas (7) and (8), but does not satisfy the other: [0070] [0080] In the above formula, ω ｉｏ = (k ｉ / j ｏ ) １／２ and ω ｏｏ = (k ｏ / j ｏ ) １／２ and k ｉ is the torsional spring constant of the first connection portion about the first axis, and k ｏ is the torsional spring constant of the second connection portion about the first axis, and j ｏ is the moment of inertia of the second movable part about the first axis.

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