Actuator device and actuator system

Abstract

To provide an actuator device and an actuator system that can precisely detect an operation quantity of a movable part.SOLUTION: An actuator device 1 comprises a wiring board, a metal substrate 3, a first electrode part 13 provided on the metal substrate 3, a driving piezoelectric body 61 arranged on the first electrode part 13, a second electrode part 14 arranged on a first principal surface 61a of the driving piezoelectric body 61, a detecting piezoelectric body 71 arranged on the second electrode part 14, a third electrode part 15 arranged on a third principal surface 71a of the detecting piezoelectric body 71, a connection part, an input part, and an output part. The connection part is electrically connected to an external reference potential and configured to make the second electrode part 14 have a potential equal to the reference potential. The input part is configured to input a drive signal to the first electrode part 13 from outside. The output part is configured to output, from the third electrode part 15 to the outside, an output signal generated by the detecting piezoelectric body 71.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an actuator device and an actuator system.

Background Art

[0002] An actuator device is known that includes a metal substrate having a movable part that can swing, a support that supports the metal substrate, a driving piezoelectric body disposed on one main surface of the metal substrate, and a detection piezoelectric body disposed on the other main surface of the metal substrate (see, for example, Patent Document 1). In such an actuator device, the driving piezoelectric body functions as a piezoelectric body for operating the movable part, and the detection piezoelectric body functions as a piezoelectric body for detecting the amount of movement of the movable part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the actuator device as described above, since the driving piezoelectric body is disposed on one main surface of the metal substrate and the detecting piezoelectric body is disposed on the other main surface of the metal substrate, variations are likely to occur in the relative positional relationship between the driving piezoelectric body and the detecting piezoelectric body. If variations occur in the positional relationship, it becomes difficult to accurately detect the operation amount of the movable part. Specifically, when a driving signal for causing the movable part to perform a resonance operation is input to the driving piezoelectric body, the output signal output from the detecting piezoelectric body includes the static strain signal from the driving piezoelectric body. Therefore, in order to obtain the resonance signal of the movable part, it is necessary to subtract the estimated static strain signal estimated to be included in the output signal from the output signal. At this time, if variations occur in the relative positional relationship between the driving piezoelectric body and the detecting piezoelectric body, variations will occur in the phase difference between the output signal and the estimated static strain signal. As a result, the accuracy of the resonance signal of the movable part deteriorates, and it becomes difficult to accurately detect the operation amount of the movable part.

[0005] An object of the present invention is to provide an actuator device and an actuator system capable of accurately detecting the operation amount of a movable part.

Means for Solving the Problems

[0006] The actuator device of the present invention includes a support, a metal substrate supported by the support, a first electrode portion provided on the metal substrate, a first piezoelectric body disposed on the first electrode portion and having a first main surface on the side opposite to the first electrode portion and a second main surface on the first electrode portion side, a second electrode portion disposed on the first main surface, a second piezoelectric body disposed on the second electrode portion and having a third main surface on the side opposite to the second electrode portion and a fourth main surface on the second electrode portion side, a third electrode portion disposed on the third main surface, a connection portion electrically connected to the second electrode portion, an input portion electrically connected to one of the first electrode portion and the third electrode portion, and an output portion electrically connected to the other of the first electrode portion and the third electrode portion. The metal substrate has a movable portion, a main body portion provided with the first electrode portion, and a connecting portion connecting the movable portion and the main body portion. Among the first piezoelectric body and the second piezoelectric body, the piezoelectric body on the side of the one electrode portion is a driving piezoelectric body for operating the movable portion, and the piezoelectric body on the side of the other electrode portion among the first piezoelectric body and the second piezoelectric body is a detecting piezoelectric body for detecting the operation amount of the movable portion. The connection portion is configured to be electrically connected to an external reference potential so that the potential of the second electrode portion becomes the reference potential. The input portion is configured to input a driving signal for driving the driving piezoelectric body from the outside to the one electrode portion. The output portion is configured to output an output signal generated in the detecting piezoelectric body from the other electrode portion to the outside.

[0007] In this actuator device, the first piezoelectric body, the second electrode portion, the second piezoelectric body, and the third electrode portion are laminated in this order on the first electrode portion provided on the metal substrate. One of the first piezoelectric body and the second piezoelectric body functions as a driving piezoelectric body for operating the movable portion, and the other of the first piezoelectric body and the second piezoelectric body functions as a detecting piezoelectric body for detecting the operation amount of the movable portion. Thus, since the driving piezoelectric body and the detecting piezoelectric body are laminated on the same side with respect to the metal substrate, variations in the relative positional relationship between the driving piezoelectric body and the detecting piezoelectric body are less likely to occur. Therefore, according to this actuator device, the operation amount of the movable portion can be accurately detected.

[0008] The actuator device of the present invention may further include a connector disposed on the support and accommodating a connection portion, an input portion, and an output portion. Thereby, electrical connection between each electrode portion and the outside can be performed simply and reliably.

[0009] In the actuator device of the present invention, when viewed in the thickness direction of the metal substrate, the outer edge of the second piezoelectric body may be located inside the outer edge of the first piezoelectric body. Thereby, since it becomes possible to arrange the second piezoelectric body while visually recognizing the first piezoelectric body during manufacturing, more accurate alignment between the first piezoelectric body and the second piezoelectric body becomes possible.

[0010] In the actuator device of the present invention, the first electrode portion may have a first electrode disposed on the second main surface. Thereby, for example, when the first piezoelectric body is a driving piezoelectric body, a driving voltage can be uniformly applied to the second main surface of the first piezoelectric body, and the driving efficiency can be improved.

[0011] The actuator device of the present invention further includes a first conductive adhesive member. The first electrode portion further includes a conductive portion integrally formed with the metal substrate and a second conductive adhesive member. The support has a first electrode pad electrically connected to the input portion or the output portion. The first electrode pad is located in a region of the surface of the support facing the metal substrate. The first adhesive member adheres the metal substrate and the first electrode pad. The second adhesive member may adhere the first electrode and the conductive portion. Thereby, the first electrode portion and the input portion, or the first electrode portion and the output portion, can be electrically connected simply and reliably.

[0012] In the actuator device of the present invention, the second electrode portion may have a second electrode disposed on the first main surface. Thereby, for example, when the second piezoelectric body is a driving piezoelectric body, a driving voltage can be uniformly applied to the fourth main surface of the second piezoelectric body, and the driving efficiency can be improved.

[0013] The actuator device of the present invention further includes a first wire. The support has a second electrode pad electrically connected to the connection portion. The second electrode pad is located in a region on the surface of the support on the side where the second electrode is disposed with respect to the metal substrate in the thickness direction of the metal substrate. The first wire may be stretched between the second electrode and the second electrode pad. Thereby, the second electrode portion and the connection portion can be electrically connected simply and reliably.

[0014] In the actuator device of the present invention, the second electrode includes a region located outside the second piezoelectric body when viewed from the thickness direction of the metal substrate, and the first wire may be stretched between the region and the second electrode pad. Thereby, the second electrode portion disposed between the first piezoelectric body and the second piezoelectric body can be electrically connected to the connection portion with a simple configuration.

[0015] In the actuator device of the present invention, the second electrode portion may further include a third electrode disposed on the fourth main surface. Thereby, for example, when the second piezoelectric body is a driving piezoelectric body, a driving voltage can be uniformly applied to the fourth main surface of the second piezoelectric body, and the driving efficiency can be improved.

[0016] In the actuator device of the present invention, the second electrode portion may further include a third adhesive member having conductivity, and the third adhesive member may adhere the second electrode and the third electrode. Thereby, input of a desired drive signal to the driving piezoelectric body and highly accurate detection of an output signal generated in the detection piezoelectric body can be realized with a simple configuration.

[0017] The actuator device of the present invention further includes a second wire. The third electrode portion has a fourth electrode disposed on the third main surface. The support has a third electrode pad electrically connected to the input portion or the output portion. The third electrode pad is located in a region on the surface of the support on the side where the fourth electrode is disposed with respect to the metal substrate in the thickness direction of the metal substrate. The second wire may be stretched between the fourth electrode and the third electrode pad. Thereby, the third electrode portion and the input portion, or the third electrode portion and the output portion, can be electrically connected simply and reliably.

[0018] In the actuator device of the present invention, the first piezoelectric body is a driving piezoelectric body, the second piezoelectric body is a detecting piezoelectric body, the first electrode portion is electrically connected to the input portion, and the third electrode portion may be electrically connected to the output portion. Thereby, since the vibration of the driving piezoelectric body is appropriately propagated to the metal substrate, desired driving characteristics can be obtained.

[0019] The actuator system of the present invention includes the above actuator device and a control unit electrically connected to the input unit and the output unit of the actuator device. The control unit has a drive signal generation unit that generates a drive signal and an output signal processing unit that processes the output signal.

[0020] In this actuator device, since the above actuator device is provided, for the same reason as the above actuator device, the operation amount of the movable part can be accurately detected.

[0021] In the actuator system of the present invention, the drive signal generation unit generates a drive signal for resonantly operating the movable part, and the output signal processing unit generates an estimated static strain signal estimated to be included in the output signal based on information regarding the frequency and amplitude of the drive signal, and may generate a resonance signal of the movable part based on the output signal and the estimated static strain signal. Thereby, when the movable part is resonated to drive the actuator device, by subtracting the estimated static strain signal from the output signal, a resonance signal corresponding to the operation amount of the movable part can be accurately generated, so that the operation amount of the movable part can be accurately detected.

Effect of the Invention

[0022] According to the present invention, it is possible to provide an actuator device and an actuator system capable of accurately detecting the operation amount of a movable part.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and overlapping descriptions are omitted. [Configuration of Actuator System]

[0025] As shown in FIG. 1, the actuator system 100 includes an actuator device 1 and a control unit 20. The actuator device 1 is electrically connected to the control unit 20. In the actuator system 100, a drive signal S1 for driving the actuator device 1 is input from the control unit 20 to the actuator device 1, and an output signal S2 generated in the actuator device 1 is output to the control unit 20 (details will be described later). [Configuration of Actuator Device]

[0026] As shown in FIGS. 2, 3, 4, and 5, the actuator device 1 includes a wiring board (support) 2, a metal substrate 3, a conductive portion 30, an adhesive member (first adhesive member) 4, an optical functional portion 5 having an optical surface 51, a driving piezoelectric element 6, a detection piezoelectric element 7, an adhesive member (second adhesive member) 8A, an adhesive member (third adhesive member) 8B, a connector 9, a wire (first wire) 11, and a wire (second wire) 12. The optical functional portion 5 is provided on the metal substrate 3. The actuator device 1 is housed, for example, in a package (not shown). As an example, the package has side walls, a bottom wall, and a top wall made of a material that transmits light, and has a box shape. For example, in the actuator device 1, when laser light is incident into the package through the top wall, the laser light is reflected by the optical surface 51 of the optical functional portion 5 that is periodically swung by the driving piezoelectric element 6 via the metal substrate 3, and is emitted to the outside through the top wall. The emission direction of the laser light from the package changes periodically and continuously according to the swing of the optical surface 51. That is, in the present embodiment, the actuator device 1 is an optical scanning device.

[0027] The wiring board 2 has a mounting surface 2a on which the metal substrate 3 is mounted. An opening 2b that opens to the mounting surface 2a and the surface opposite to the mounting surface 2a is formed in the wiring board 2. The wiring board 2 has, for example, a rectangular frame shape. Examples of the material of the wiring board 2 include silicon, ceramic, quartz, glass, and plastic. As the wiring board 2, for example, a glass composite substrate (CEM-3) in which a base material obtained by mixing a glass cloth and a glass non-woven fabric is impregnated with an epoxy resin, a glass epoxy substrate (FR-4) in which glass fiber-made cloths are stacked and impregnated with an epoxy resin, a metal heat dissipation substrate using copper, aluminum, or the like as a base material, or the like can be used. The thickness of the wiring board 2 may be a thickness that can ensure sufficient rigidity, and is, for example, 0.8 mm or more. In the present embodiment, the thickness of the wiring board 2 is 1.6 mm. In the following description, the thickness direction of the wiring board 2 is referred to as the Z-axis direction (the thickness direction of the metal substrate), a direction perpendicular to the Z-axis direction is referred to as the X-axis direction, and a direction perpendicular to both the Z-axis direction and the X-axis direction is referred to as the Y-axis direction.

[0028] The wiring board 2 has a plurality (three in this embodiment) of electrode pads (second electrode pads) 21, an electrode pad (third electrode pad) 22, and an electrode pad (first electrode pad) 23. The electrode pads 21, 22, and 23 are arranged (provided) on the mounting surface 2a. The plurality of electrode pads 21, 22, and 23 are located on one side in the Y-axis direction with respect to the opening 2b of the wiring board 2 and are arranged along the X-axis direction.

[0029] The connector 9 is attached (arranged) to the mounting surface 2a of the wiring board 2. The connector 9 is a port for inputting and outputting voltage signals and the like to and from each of the driving piezoelectric element 6 and the detection piezoelectric element 7. The connector 9 is, for example, a general-purpose connector into which a flexible printed circuit board (not shown) electrically connected to the control unit 20 is inserted. The connector 9 is electrically connected to the control unit 20 via a flexible printed circuit board or the like. The type of the connector 9 is not limited. The connector 9 is located, for example, on one side in the Y-axis direction with respect to the plurality of electrode pads 21, 22, and 23. The connector 9 has a plurality of terminals 90. The connector 9 is electrically connected to the plurality of electrode pads 21, 22, and 23 via the plurality of terminals 90 and the wiring of the wiring board 2.

[0030] The metal substrate 3 is supported by the wiring board 2. The metal substrate 3 is made of, for example, a metal such as an iron-based, stainless steel-based, copper-based, permalloy-based, titanium-based, tungsten-based, or molybdenum-based metal and has a plate shape. The thickness of the metal substrate 3 is, for example, 50 to 500 μm. The adhesive member 4 adheres the wiring board 2 and the metal substrate 3. The adhesive member 4 has conductivity. An example of the material of the adhesive member 4 is an epoxy resin containing Ag particles.

[0031] The metal substrate 3 has a main body portion 31, a movable portion 32, a first extending portion 33, a second extending portion 34, a first coupling portion (coupling portion) 35, a second coupling portion (coupling portion) 36, a first connecting portion 37, a second connecting portion 38, and a third connecting portion 39. The movable portion 32, the first extending portion 33, the second extending portion 34, the first connecting portion 35, the second connecting portion 36, the first connecting portion 37, the second connecting portion 38, and the third connecting portion 39 are integrally formed.

[0032] When viewed from the Z-axis direction, the main body part 31 is located inside the opening 2b of the wiring substrate 2. The movable part 32 is a portion where the optical function part 5 is located. The movable part 32 is located on the other side of the main body part 31 in the Y-axis direction.

[0033] The first extension portion 33 and the second extension portion 34 extend from the main body portion 31 so that the movable portion 32 is located between them. In this embodiment, the movable portion 32 is located midway between the first extension portion 33 and the second extension portion 34. The first extension portion 33 and the second extension portion 34 extend parallel to each other, for example, along the Y-axis direction. In this embodiment, the first extension portion 33 has the same shape as the second extension portion 34.

[0034] The first connecting portion 35 extends along the X-axis direction between the first extending portion 33 and the movable portion 32. One end of the first connecting portion 35 is connected to the first extending portion 33, and the other end of the first connecting portion 35 is connected to the movable portion 32. In other words, the first connecting portion 35 connects the first extending portion 33 and the movable portion 32, thereby connecting the movable portion 32 and the main body portion 31 via the first extending portion 33.

[0035] The second connecting portion 36 extends along the X-axis direction between the second extending portion 34 and the movable portion 32. One end of the second connecting portion 36 is connected to the second extending portion 34, and the other end of the second connecting portion 36 is connected to the movable portion 32. In other words, the second connecting portion 36 connects the second extending portion 34 and the movable portion 32, thereby connecting the movable portion 32 and the main body portion 31 via the second extending portion 34.

[0036] In this embodiment, the first connecting portion 35 and the second connecting portion 36 are located on a single straight line along the X-axis direction. Due to the positional relationship between the first extending portion 33 and the second extending portion 34 and the movable portion 32 described above, the length of the first connecting portion 35 in the X-axis direction is the same as the length of the second connecting portion 36 in the X-axis direction. In this embodiment, the first connecting portion 35 has the same shape as the second connecting portion 36.

[0037] The movable portion 32, the first extending portion 33, the second extending portion 34, the first connecting portion 35, and the second connecting portion 36 are located within the opening 2b of the wiring substrate 2 when viewed from the Z-axis direction. The first connecting portion 35 and the second connecting portion 36 function as torsion bars that elastically deform so as to twist in response to deformation (displacement) of the first extending portion 33 and the second extending portion 34. The movable portion 32 swings about an axis along the X-axis direction in response to the elastic deformation of the first connecting portion 35 and the second connecting portion 36. In other words, the movable portion 32 is swingably supported by the first extending portion 33 and the second extending portion 34 via the first connecting portion 35 and the second connecting portion 36.

[0038] The optical function unit 5 is disposed on the surface of the movable unit 32 opposite to the opening 2b. The optical function unit 5 has, for example, a disk shape. The optical function unit 5 is attached to the movable unit 32 so that the optical surface 51 faces away from the movable unit 32. The optical surface 51 is located midway between the first extension unit 33 and the second extension unit 34 in the X-axis direction. In this embodiment, the metal substrate 3 and the optical surface 51 each have a shape that is line-symmetrical with respect to a line passing through the center of the optical surface 51 along the Y-axis direction. As an example, the optical function unit 5 is made of a semiconductor material such as silicon or glass, and the optical surface 51 is formed by a reflective film formed on the surface of the optical function unit 5 opposite to the movable unit 32. In other words, the optical surface 51 is a mirror surface (reflective surface). The reflective film of the optical function unit 5 can be omitted. In that case, the opposite surface itself may serve as the optical surface 51.

[0039] The first connection portion 37 is connected to the first extending portion 33. The first connection portion 37 is located on the other side in the Y-axis direction with respect to the first extending portion 33. In the first connection portion 37, the portion on the other side in the Y-axis direction faces a part of the wiring board 2. An adhesive member 4 is disposed between the portion on the other side of the first connection portion 37 and the part of the wiring board 2. Note that an electrode pad (not shown) electrically connected to the electrode pad 23 may be disposed on the part of the wiring board 2 so as to have the same potential as the electrode pad 23.

[0040] The second connection portion 38 is connected to the second extending portion 34. The second connection portion 38 is located on the other side in the Y-axis direction with respect to the second extending portion 34. In the second connection portion 38, the portion on the other side in the Y-axis direction faces a part of the wiring board 2. An adhesive member 4 is disposed between the portion on the other side of the second connection portion 38 and the part of the wiring board 2. Note that an electrode pad (not shown) electrically connected to the electrode pad 23 may be disposed on the part of the wiring board 2 so as to have the same potential as the electrode pad 23. In the present embodiment, the first connection portion 37 and the second connection portion 38 are in a line-symmetric relationship with respect to a straight line passing through the center of the optical surface 51 along the Y-axis direction.

[0041] The third connection portion 39 is connected to the main body portion 31. The third connection portion 39 is located on one side in the Y-axis direction with respect to the main body portion 31. In the third connection portion 39, the portion on one side in the Y-axis direction faces a part of the wiring board 2 (the part where the electrode pad 23 is disposed). An adhesive member 4 is disposed between the portion on one side of the third connection portion 39 and the part of the wiring board 2. The adhesive member 4 adheres the third connection portion 39 and the electrode pad 23.

[0042] As shown in FIG. 5, the conductive portion 30 is integrally formed with the metal substrate 3. The conductive portion 30 is located on the side opposite to the opening 2b in the metal substrate 3 and the members constituting the conductive portion 30. The conductive portion 30 faces the electrode 63 of the piezoelectric element 6 for driving. The conductive portion 30 has a surface 30a on the side opposite to the opening 2b. The surface 30a is formed on the same plane as the main surface 31a on the side opposite to the opening 2b in the main body portion 31. The conductive portion 30 is made of a conductive material and is electrically connected to the metal substrate 3. The conductive portion 30 functions as a part of the first electrode portion 13 for inputting a voltage signal to the driving piezoelectric body 61 of the driving piezoelectric element 6. Details of the first electrode portion 13 will be described later. In FIGS. 2 and 3, the illustration of the conductive portion 30 is omitted.

[0043] The piezoelectric element 6 for driving is an element for generating a plate wave in the metal substrate 3 to drive the actuator device 1. The piezoelectric element 6 for driving is disposed on the surface 30a of the conductive portion 30. The center of the piezoelectric element 6 for driving in the X-axis direction coincides with the center of the movable portion 32 in the X-axis direction (that is, the center of the optical surface 51 in the X-axis direction). The piezoelectric element 6 for driving includes a driving piezoelectric body (first piezoelectric body, piezoelectric body on one electrode portion side) 61, an electrode (second electrode) 62, and an electrode (first electrode) 63 (see FIG. 5).

[0044] The piezoelectric body 61 for driving is a piezoelectric body for operating the movable part 32. In the present embodiment, the piezoelectric body 61 for driving swings the movable part 32. The piezoelectric body 61 for driving includes a first main surface 61a and a second main surface 61b (see FIG. 5). The first main surface 61a is the main surface on the opposite side of the surface 30a in the piezoelectric body 61 for driving. An electrode 62 is disposed on the first main surface 61a. The second main surface 61b is the main surface on the side of the surface 30a in the piezoelectric body 61 for driving. An electrode 63 is disposed on the second main surface 61b. Each of the electrode 62 and the electrode 63 is, for example, a Ni / Au layer. In the Ni / Au layer, the Ni layer is disposed on the first main surface 61a, the Au layer is disposed on the Ni layer, and the thickness of the Ni layer is larger than the thickness of the Au layer. Each of the piezoelectric body 61 for driving, the electrode 62, and the electrode 63 has, for example, a rectangular plate shape. The piezoelectric body 61 for driving is electrically connected to the electrode 62 by being joined to the electrode 62. The piezoelectric body 61 for driving is electrically connected to the electrode 63 by being joined to the electrode 63. An adhesive member 8A is disposed between the electrode 63 and the main body part 31. The adhesive member 8A adheres the piezoelectric body 61 for driving, the metal substrate 3, and the conductive part 30. The adhesive member 8A has conductivity. Examples of the material of the adhesive member 8A include an epoxy resin containing Ag particles.

[0045] The piezoelectric element 7 for detection is an element for detecting the operating amount of the movable part 32. In the present embodiment, the piezoelectric element 7 for detection detects the swing angle and phase of the movable part 32. Details of the phase of the movable part 32 will be described later. The piezoelectric element 7 for detection is disposed on the surface 62a. The surface 62a is the main surface on the opposite side of the driving piezoelectric body 61 in the electrode 62. The center of the piezoelectric element 7 for detection in the X-axis direction coincides with the center of the driving piezoelectric element 6 in the X-axis direction. The piezoelectric element 7 for detection includes a detection piezoelectric body (second piezoelectric body, piezoelectric body on the other electrode part side) 71, an electrode (fourth electrode) 72, and an electrode (third electrode) 73 (see FIG. 5). The detection piezoelectric body 71 is a piezoelectric body for detecting the operating amount of the movable part 32. In the present embodiment, the detection piezoelectric body 71 detects the swing angle and phase of the movable part 32. The detection piezoelectric body 71 includes a third main surface 71a and a fourth main surface 71b (see FIG. 5). The third main surface 71a is the main surface on the opposite side of the electrode 62 in the detection piezoelectric body 71. The electrode 72 is disposed on the third main surface 71a. The fourth main surface 71b is the main surface on the electrode 62 side in the detection piezoelectric body 71. The electrode 73 is disposed on the fourth main surface 71b. Each of the electrode 72 and the electrode 73 is, for example, a Ni / Au layer. Each of the detection piezoelectric body 71, the electrode 72, and the electrode 73 has, for example, a rectangular plate shape. The detection piezoelectric body 71 is electrically connected to the electrode 72 by being joined to the electrode 72. The driving piezoelectric body 61 is electrically connected to the electrode 73 by being joined to the electrode 73. An adhesive member 8B is disposed between the electrode 73 and the electrode 62. The adhesive member 8B adheres the detection piezoelectric body 71 and the driving piezoelectric body 61. The adhesive member 8B has conductivity. An example of the material of the adhesive member 8B is an epoxy resin containing Ag particles. [Configuration of Piezoelectric Unit]

[0046] Here, the actuator device 1 includes a piezoelectric unit 10. The piezoelectric unit 10 is composed of the above-described metal substrate 3, the driving piezoelectric element 6, the detection piezoelectric element 7, the adhesive member 8A, and the adhesive member 8B. Hereinafter, the configuration of the piezoelectric unit 10 will be described in more detail with reference to FIGS. 4 and 5.

[0047] The driving piezoelectric body 61 of the driving piezoelectric element 6 further includes a side surface 61c. The driving piezoelectric element 6 is arranged on the surface 30a of the conductive part 30 so that a part of the main surface 31a of the main body part 31 is located outside the side surface 61c of the driving piezoelectric body 61. As a result, a corner C1 is formed by a part of the main surface 31a and the side surface 61c of the driving piezoelectric body 61. The part of the main surface 31a is the part of the main surface 31a that is outside the side surface 61c. The side surface 61c corresponds to the outer edge 61d of the driving piezoelectric body 61 when viewed from the Z-axis direction.

[0048] The adhesive member 8A includes a first portion 81 and a second portion 82. The first portion 81 is a portion disposed between the surface 30a of the conductive portion 30 and the driving piezoelectric element 6. The second portion 82 is continuous with the first portion 81 and disposed at the corner C1. "The second portion 82 is continuous with the first portion 81" means that the first portion 81 and the second portion 82 are integrally formed without an interface. The second portion 82 contacts the side surface 61c of the driving piezoelectric element 61 and a portion of the main surface 31a of the main body portion 31. In this embodiment, the surface of the second portion 82 is flat. As an example, the second portion 82 is continuous over the entire corner C1 when viewed from the Z-axis direction.

[0049] At least a part of the second portion 82 reaches a region on the electrode 62 side of the side surface 61c of the driving piezoelectric body 61. "At least a part of the second portion 82 reaches a region on the electrode 62 side of the side surface 61c of the driving piezoelectric body 61" means that the second portion 82 is in contact with a half region of the side surface 61c on the electrode 62 side in the Z-axis direction. In addition, the second portion 82 does not reach the outer edge 611 of the first main surface 61a. In other words, the highest edge of the second portion 82 does not contact the outer edge 611. In other words, the adhesive member 8A arranged on the main surface 31a of the metal substrate 3 and the surface 30a of the conductive portion 30 does not reach the electrode 62.

[0050] As an example, the height of the first portion 81 in the Z-axis direction is 10 to 100 μm. The height of the second portion 82 in the Z-axis direction is greater than the sum of the height of the first portion 81 in the Z-axis direction and the thickness of the electrode 63, and is equal to or less than the sum of the height of the first portion 81 in the Z-axis direction, the thickness of the electrode 63, and the thickness of the driving piezoelectric body 61. As an example, the height of the second portion 82 is 15 μm to 300 μm. As an example, the width of the second portion 82 in the X-axis direction and the Y-axis direction is 100 to 500 μm. The "width of the second portion 82 in the X-axis direction and the Y-axis direction" includes the width by which the second portion 82 protrudes from the side surface 61 c of the driving piezoelectric body 61 in the cross section of the driving piezoelectric element 6 and the adhesive member 8A taken along the Y-axis direction, and the width by which the second portion 82 protrudes from the side surface 61 c of the driving piezoelectric body 61 in the cross section of the driving piezoelectric element 6 and the adhesive member 8A taken along the X-axis direction. The driving piezoelectric element 61 has a shape whose center point can be identified, and when viewed from the Z-axis direction, the shape is point-symmetrical with respect to the center point. As an example, the driving piezoelectric element 61 has a rectangular plate shape, and the width of the driving piezoelectric element 61 in the X-axis direction and the width of the driving piezoelectric element 61 in the Y-axis direction are each, for example, 2 to 20 mm, and the thickness of the driving piezoelectric element 61 is approximately 200 μm. As an example, the driving piezoelectric element 61 has a rectangular plate shape with the X-axis direction as the longitudinal direction. As an example, the thickness of the electrode 62 and the thickness of the electrode 63 are each 1 to 2 μm. Furthermore, as an example, the adhesive member 8A has a Young's modulus of 1 MPa or more.

[0051] The width of the electrode 62 in the X-axis direction is smaller than the width of the driving piezoelectric body 61 in the X-axis direction, and the width of the electrode 62 in the Y-axis direction is smaller than the width of the driving piezoelectric body 61 in the Y-axis direction. Furthermore, when viewed from the Z-axis direction, the outer edge 62c of the electrode 62 is located inside the outer edge 61d of the driving piezoelectric body 61. "When viewed from the Z-axis direction, the outer edge 62c of the electrode 62 is located inside the outer edge 61d of the driving piezoelectric body 61" means that when viewed from the Z-axis direction, the outer edge 61d of the driving piezoelectric body 61 surrounds the outer edge 62c of the electrode 62. In other words, when viewed from the Z-axis direction, the outer edge 62c is offset from the outer edge 61d toward the center of the driving piezoelectric body 61. For example, when viewed from the Z-axis direction, the distance between the outer edges 62c and 61d is greater than the thickness of the driving piezoelectric body 61. The distance between the outer edges 62c and 61d is, for example, approximately 250 μm. In this embodiment, the distance between outer edge 62c and outer edge 61d when viewed from the Z-axis direction is greater than the distance between the highest edge of second portion 82 and outer edge 611 of first main surface 61a when viewed from the X-axis direction. This configuration reliably prevents conductive adhesive member 8A from coming into contact with electrode 62. The distance between the highest edge of second portion 82 and outer edge 611 when viewed from the X-axis direction is, for example, approximately 50 μm.

[0052] The detecting piezoelectric body 71 of the detecting piezoelectric element 7 further includes a side surface 71c. The detecting piezoelectric element 7 is disposed on the surface 62a such that a portion of the surface 62a of the electrode 62 is located outside the side surface 71c of the detecting piezoelectric body 71. As a result, a corner C2 is formed by the portion of the surface 62a of the electrode 62 and the side surface 71c of the detecting piezoelectric body 71. The portion of the surface 62a is the portion of the surface 62a that is outside the side surface 71c. The side surface 71c corresponds to the outer edge 71d of the detecting piezoelectric body 71 when viewed from the Z-axis direction.

[0053] The connecting member 8B further includes a third portion 83 and a fourth portion 84. The third portion 83 is a portion disposed between the surface 62a of the electrode 62 and the detection piezoelectric element 7. The fourth portion 84 is continuous from the third portion 83 and is disposed at the corner portion C2. "The fourth portion 84 is continuous from the third portion 83" means that the third portion 83 and the fourth portion 84 are integrally formed without an interface. The fourth portion 84 is in contact with a part of the side surface 71c of the detection piezoelectric body 71 and the surface 62a of the electrode 62. In the present embodiment, the surface of the fourth portion 84 is flat. As an example, the fourth portion 84 is continuous over the entire corner portion C2 when viewed from the Z-axis direction.

[0054] At least a part of the fourth portion 84 reaches the region on the electrode 72 side in the side surface 71c of the detection piezoelectric body 71. "At least a part of the fourth portion 84 reaches the region on the electrode 72 side in the side surface 71c of the detection piezoelectric body 71" means that the fourth portion 84 is in contact with the region of the side surface 71c on the electrode 72 side in the Z-axis direction. Also, the fourth portion 84 does not reach the outer edge 711 of the third main surface 71a. That is, the highest edge portion of the fourth portion 84 does not contact the outer edge 711. That is, the adhesive member 8B disposed on the surface 62a of the electrode 62 does not reach the electrode 72.

[0055] For example, the height of the third portion 83 in the Z-axis direction is 10 to 100 μm. The height of the fourth portion 84 in the Z-axis direction is greater than the sum of the height of the third portion 83 in the Z-axis direction and the thickness of the electrode 73, and is equal to or less than the sum of the height of the third portion 83, the thickness of the electrode 73, and the thickness of the detecting piezoelectric body 71 in the Z-axis direction. For example, the height of the fourth portion 84 is 15 μm to 300 μm. For example, the width of the fourth portion 84 in the X-axis direction and the Y-axis direction is 100 to 500 μm. The "width of the fourth portion 84 in the X-axis direction and the Y-axis direction" includes the width by which the fourth portion 84 protrudes from the side surface 71 c of the detecting piezoelectric body 71 in the cross section of the detecting piezoelectric element 7 and the adhesive member 8B taken along the Y-axis direction, and the width by which the fourth portion 84 protrudes from the side surface 71 c of the detecting piezoelectric body 71 in the cross section of the detecting piezoelectric element 7 and the adhesive member 8B taken along the X-axis direction. The detecting piezoelectric element 71 has a shape whose center point can be identified, and when viewed from the Z-axis direction, the shape is point-symmetrical with respect to the center point. As an example, the detecting piezoelectric element 71 has a rectangular plate shape, and the width of the detecting piezoelectric element 71 in the X-axis direction and the width of the detecting piezoelectric element 71 in the Y-axis direction are each, for example, 2 to 20 mm, and the thickness of the detecting piezoelectric element 71 is approximately 200 μm. As an example, the detecting piezoelectric element 71 has a square plate shape whose width in the X-axis direction and the width in the Y-axis direction are approximately the same. As an example, the thickness of the electrode 72 and the thickness of the electrode 73 are each 1 to 2 μm.

[0056] The width of the electrode 72 in the X-axis direction is smaller than the width of the detection piezoelectric body 71 in the X-axis direction, and the width of the electrode 72 in the Y-axis direction is smaller than the width of the detection piezoelectric body 71 in the Y-axis direction. Furthermore, when viewed from the Z-axis direction, the outer edge 72c of the electrode 72 (the outer edge corresponding to the side surface 72b of the electrode 72) is located more inward than the outer edge 71d of the detection piezoelectric body 71. "When viewed from the Z-axis direction, the outer edge 72c of the electrode 72 is located more inward than the outer edge 71d of the detection piezoelectric body 71" means that when viewed from the Z-axis direction, the outer edge 71d of the detection piezoelectric body 71 surrounds the outer edge 72c of the electrode 72. In other words, when viewed from the Z-axis direction, the outer edge 72c is offset from the outer edge 71d toward the center of the detection piezoelectric body 71. For example, the distance between the outer edge 72c and the outer edge 71d when viewed from the Z-axis direction is greater than the thickness of the detection piezoelectric body 71. The distance between the outer edges 72c and 71d is, for example, approximately 250 μm, similar to the distance between the outer edges 62c and 61d. For example, if the electrode 72 has a square plate shape when viewed from the Z-axis direction, the distance between the outer edges 72c and 71d may be smaller than the distance between the outer edges 62c and 61d when viewed from the Z-axis direction. This is because the amount and range of the adhesive member 8B that protrudes from the square plate-shaped detection piezoelectric element 71 (and electrode 73) is easier to control than when the detection piezoelectric element 71 (and electrode 73) has a rectangular plate shape. Furthermore, if the detection piezoelectric element 71 has a square plate shape, the amount and range of the adhesive member 8B that protrudes from the detection piezoelectric element 71 is easier to control, making it easier for the adhesive member 8B to be disposed over the entire corner C2. In this embodiment, the distance between outer edge 72c and outer edge 71d when viewed from the Z-axis direction is longer than the distance between the highest edge of fourth portion 84 and outer edge 711 of third main surface 71a when viewed from the X-axis direction. This configuration reliably prevents conductive adhesive member 8B from contacting electrode 72. The distance between the highest edge of fourth portion 84 and outer edge 711 when viewed from the X-axis direction is, for example, approximately 50 μm.

[0057] The width of the detection piezoelectric element 71 in the X-axis direction is smaller than the width of the drive piezoelectric element 61 in the X-axis direction, and the width of the detection piezoelectric element 71 in the Y-axis direction is smaller than the width of the drive piezoelectric element 61 in the Y-axis direction. Furthermore, when viewed from the Z-axis direction, the outer edge 71d of the detection piezoelectric element 71 is located more inward than the outer edge 61d of the drive piezoelectric element 61. "When viewed from the Z-axis direction, the outer edge 71d of the detection piezoelectric element 71 is located more inward than the outer edge 61d of the drive piezoelectric element 61" means that when viewed from the Z-axis direction, the outer edge 61d of the drive piezoelectric element 61 surrounds the outer edge 71d of the detection piezoelectric element 71. In other words, when viewed from the Z-axis direction, the outer edge 71d is offset from the outer edge 61d toward the center of the detection piezoelectric element 71.

[0058] In this embodiment, as shown in FIGS. 3 and 4 , the driving piezoelectric element 61 and the detecting piezoelectric element 71 are arranged such that the center point of the driving piezoelectric element 61 and the center point of the detecting piezoelectric element 71 coincide with each other when viewed from the Z-axis direction. When viewed from the Z-axis direction, the driving piezoelectric element 61 is arranged so as to be line-symmetrical about a line that passes through the center point of the driving piezoelectric element 61 along the X-axis direction, and so as to be line-symmetrical about a line that passes through the center point of the driving piezoelectric element 61 along the Y-axis direction. When viewed from the Z-axis direction, the detecting piezoelectric element 71 is arranged so as to be line-symmetrical about a line that passes through the center point of the detecting piezoelectric element 71 along the X-axis direction, and so as to be line-symmetrical about a line that passes through the center point of the detecting piezoelectric element 71 along the Y-axis direction. The Y-axis direction is the direction in which the main body unit 31 and the movable unit are aligned.

[0059] As shown in FIG. 5, the actuator device 1 further includes a first electrode portion 13, a second electrode portion 14, and a third electrode portion 15. The first electrode portion 13 is provided on the metal substrate 3. The first electrode portion 13 has a conductive portion 30, an adhesive member 8A, and an electrode 63 of the driving piezoelectric element 6. In the present embodiment, the first electrode portion 13 is composed of the conductive portion 30, at least a part of the adhesive member 8A, and the electrode 63. At least a part of the adhesive member 8A is, for example, a portion (i.e., the first portion 81) disposed between the conductive portion 30 and the electrode 63 in the adhesive member 8A. In the first electrode portion 13, the electrode 63 and the conductive portion 30 are adhered by the adhesive member 8A. A driving piezoelectric body 61 is disposed on the first electrode portion 13. The second electrode portion 14 is disposed on the first main surface 61a of the driving piezoelectric body 61. The first main surface 61a is the main surface on the side opposite to the first electrode portion 13, and the second main surface 61b is the main surface on the side of the first electrode portion 13. The second electrode portion 14 has an electrode 62 of the driving piezoelectric element 6, an adhesive member 8B, and an electrode 73 of the detection piezoelectric element 7. In the present embodiment, the second electrode portion 14 is composed of the electrode 62, at least a part of the adhesive member 8B, and the electrode 73. At least a part of the adhesive member 8B is, for example, a portion (i.e., the third portion 83) disposed between the electrode 62 and the electrode 73 in the adhesive member 8B. In the second electrode portion 14, the electrode 62 and the electrode 73 are adhered by the adhesive member 8B. A detection piezoelectric body 71 is disposed on the second electrode portion 14. The third electrode portion 15 is disposed on the third main surface 71a of the detection piezoelectric body 71. The third main surface 71a is the main surface on the side opposite to the second electrode portion 14, and the fourth main surface 71b is the main surface on the side of the second electrode portion 14. The third electrode portion 15 has an electrode 72 of the detection piezoelectric element 7. In the present embodiment, the third electrode portion 15 is composed of the electrode 72. As described above, the driving piezoelectric body 61 is disposed between the first electrode portion 13 and the second electrode portion 14, and the detection piezoelectric body 71 is disposed between the second electrode portion 14 and the third electrode portion 15.

[0060] As shown in FIG. 1, the actuator device 1 further includes an input portion 91, a connection portion 92, and an output portion 93. The input portion 91, the connection portion 92, and the output portion 93 are accommodated in the connector 9.

[0061] The input unit 91 is configured to input a drive signal S1 for driving the driving piezoelectric element 61 from the control unit 20 to the first electrode unit 13. Specifically, the input unit 91 is a terminal in the connector 9 that electrically connects the control unit 20 and the first electrode unit 13 to input the drive signal S1 to the first electrode unit 13 (details will be described later). The input unit 91 is electrically connected to a terminal 90a (see FIG. 3) included in the plurality of terminals 90. The input unit 91 is also electrically connected to the control unit 20 via, for example, a flexible printed circuit board or the like. The connection unit 92 is configured to be connected to a reference potential (fixed potential) outside the actuator device 1. Specifically, the connection unit 92 is a terminal in the connector 9 that electrically connects the second electrode unit 14 to the reference potential so that the potential of the second electrode unit 14 becomes the reference potential (details will be described later). The connection unit 92 is electrically connected to a terminal 90b (see FIG. 3) included in the plurality of terminals 90. Furthermore, the connection unit 92 is connected to, for example, a reference potential within the actuator system 100 via, for example, a flexible printed circuit board or the like. The connection unit 92 may also be connected to a reference potential outside the actuator system 100. The output unit 93 is configured to output the output signal S2 generated in the detection piezoelectric element 71 from the third electrode unit 15 to the outside. Specifically, the output unit 93 is a terminal in the connector 9 that electrically connects the control unit 20 and the third electrode unit 15 to output the output signal S2 generated in the third electrode unit 15 to the control unit 20 (details will be described later). The output unit 93 is electrically connected to a terminal 90c (see FIG. 3) included in the plurality of terminals 90. [Electrical connection relationship of the actuator system]

[0062] The first electrode portion 13 is electrically connected to the electrode pad 23. Specifically, as shown in FIGS. 2, 3, and 5, at least a part of the conductive portion 30 constituting the first electrode portion 13, the adhesive member 8A, and the electrode 63 of the driving piezoelectric element 6 are electrically connected to the electrode pad 23 via the metal substrate 3 and the adhesive member 4 disposed between the third connection portion 39 of the metal substrate 3 and the electrode pad 23. The electrode pad 23 is electrically connected to the input portion 91 via the wiring of the wiring substrate 2 and the terminal 90a of the connector 9. The electrode pad 23 is located on the mounting surface 2a (specifically, the region facing the metal substrate 3 on the mounting surface 2a) of the surface of the wiring substrate 2. That is, the first electrode portion 13 is electrically connected to the input portion 91 of the connector 9 via the metal substrate 3, the adhesive member 4, the electrode pad 23, the wiring of the wiring substrate 2, and the terminal 90a. Further, the input portion 91 is electrically connected to the control portion 20 via, for example, a flexible printed circuit board or the like. That is, the input portion 91 electrically connects the control portion 20 and the first electrode portion 13.

[0063] The second electrode portion 14 is electrically connected to the electrode pad 21. Specifically, at least a part of the electrode 62, the adhesive member 8B, and the electrode 73 that constitute the second electrode portion 14 are electrically connected to the electrode pad 21 via the wire 11. The wire 11 is stretched between the electrode 62 of the second electrode portion 14 and the electrode pad 21. Specifically, the wire 11 is stretched between the region 621 on the surface 62a of the electrode 62 and the electrode pad 21. The region 621 is a region on the surface 62a of the electrode 62 that is located outside the detection piezoelectric body 71 when viewed from the Z-axis direction. The electrode pad 21 is located in a region (i.e., the mounting surface 2a) on the surface of the wiring substrate 2 on the side where the electrode 62 is disposed with respect to the metal substrate 3 in the Z-axis direction. The electrode pad 21 is electrically connected to the connection portion 92 via the wiring of the wiring substrate 2 and the terminal 90b of the connector 9. That is, the second electrode portion 14 is electrically connected to the connection portion 92 of the connector 9 via the wire 11, the electrode pad 21, the wiring of the wiring substrate 2, and the terminal 90b. Further, the connection portion 92 is connected to a reference potential (e.g., ground potential) in the actuator system 100 via, for example, a flexible printed circuit board or the like. That is, the connection portion 92 electrically connects the control unit 20 and the second electrode portion 14.

[0064] The third electrode portion 15 is electrically connected to the electrode pad 22. Specifically, the electrode 72 of the detection piezoelectric element 7 that constitutes the third electrode portion 15 is electrically connected to the electrode pad 22 via the wire 12. The wire 12 is stretched between the electrode 72 of the third electrode portion 15 and the electrode pad 22. The electrode pad 22 is located in a region (i.e., the mounting surface 2a) on the surface of the wiring substrate 2 on the side where the electrode 72 is disposed with respect to the metal substrate 3 in the Z-axis direction. The electrode pad 22 is electrically connected to the terminal 90c of the connector 9 via the wiring of the wiring substrate 2. That is, the third electrode portion 15 is electrically connected to the output portion 93 of the connector 9 via the wire 12, the electrode pad 22, the wiring of the wiring substrate 2, and the terminal 90c. Further, the output portion 93 is electrically connected to the control unit 20 via, for example, a flexible printed circuit board or the like. That is, the output portion 93 electrically connects the control unit 20 and the third electrode portion 15.

[0065] With the electrical connections described above, the actuator device 1 is driven, for example, as follows. Specifically, with the second electrode portion 14 (specifically, the electrode 62 of the driving piezoelectric element 6, at least a portion of the adhesive member 8B, and the electrode 73 of the detecting piezoelectric element 7) connected to a reference potential via the wire 11, the electrode pad 21, the wiring of the wiring board 2, the terminal 90b of the connector 9, and the connection portion 92, and the potential of the second electrode portion 14 is at the reference potential, a drive signal S1, which is a voltage signal for causing the movable portion 32 of the actuator device 1 to resonate, is input from the control unit 20 to the first electrode portion 13 (specifically, the conductive portion 30, at least a portion of the adhesive member 8A, and the electrode 63 of the driving piezoelectric element 6) via the input portion 91 and terminal 90a of the connector 9, the wiring of the wiring board 2, the electrode pad 23, the adhesive member 4, and the metal substrate 3. This causes the driving piezoelectric body 61 to deform and / or vibrate, generating periodic plate waves in the main body portion 31. The generation of this periodic plate wave induces torsional vibration (torsional resonance) in the first connecting portion 35 and the second connecting portion 36, causing the movable portion 32 and the optical surface 51 to oscillate. That is, in the actuator device 1, the torsional resonance system of the first connecting portion 35, the second connecting portion 36, the movable portion 32, and the optical surface 51 is positioned apart from the driving piezoelectric element 6, and a Lamb wave resonance structure is employed, thereby generating torsional resonance with high drive efficiency. Meanwhile, an output signal S2 generated in the detecting piezoelectric element 71 is output from the third electrode portion 15 (specifically, the electrode 72 of the detecting piezoelectric element 7) via the wire 12, the electrode pad 22, the wiring of the wiring board 2, the terminal 90c of the connector 9, and the output portion 93 to the control unit 20, whereby the oscillation angle and phase of the optical surface 51 are detected. The output signal S2 is a voltage signal corresponding to the changes in angle and phase due to the oscillation of the movable portion 32 and the optical surface 51. When viewed from the Z-axis direction, the center point of the driving piezoelectric element 61 coincides with the center point of the detecting piezoelectric element 71. The driving piezoelectric element 61 is arranged so as to be symmetrical with respect to both a line passing through the center point of the driving piezoelectric element 61 along the X-axis direction and a line passing through the center point of the driving piezoelectric element 61 along the Y-axis direction, and the detecting piezoelectric element 71 is arranged so as to be symmetrical with respect to both a line passing through the center point of the detecting piezoelectric element 71 along the X-axis direction and a line passing through the center point of the detecting piezoelectric element 71 along the Y-axis direction.By the driving piezoelectric body 61 and the detection piezoelectric body 71 having the positional relationship as described above, in the actuator device 1, when the drive signal S1 is input to the first electrode portion 13, the movement of the driving piezoelectric body 61 and the movement of the detection piezoelectric body 71 coincide with each other. [Configuration of the control unit]

[0066] The control unit 20 generates a sine-wave drive signal S1 for resonantly vibrating the movable part 32, and inputs the generated drive signal S1 to the input part 91 of the connector 9. Further, the control unit 20 acquires the sine-wave output signal S2 output from the output part 93. Then, the control unit 20 processes the acquired output signal S2, and repeats processes such as regenerating the drive signal S1 based on the result of processing the output signal S2. Here, the phase of the movable part 32 that swings when the drive signal S1 is input to the input part 91 is the difference between the phase of the drive signal S1 and the phase of the signal indicating the displacement of the movable part 32 on the same time axis. That is, the phase of the movable part 32 indicates how much the phase indicating the displacement of the movable part 32 lags, for example, by 10° when the drive signal S1 is used as a reference.

[0067] The conditions of the frequency and amplitude of the drive signal S1 for the movable part 32 to perform a resonant operation actually change due to the change in the operating temperature of the actuator device 1. Therefore, in order for the movable part 32 to perform a resonant operation, it is necessary to appropriately change the frequency and amplitude of the drive signal S1 according to the change in the operating temperature. Thus, the control unit 20 generates an appropriate drive signal S1 for resonantly vibrating the movable part 32 based on the output signal S2 generated in the piezoelectric body 71 for detection. Here, the output signal S2 generated in the piezoelectric body 71 for detection actually includes not only the resonant signal corresponding to the swing angle and phase of the movable part 32 but also the static strain signal. That is, in the piezoelectric body 71 for detection, not only the vibration and torsion of the movable part 32 due to resonance but also the static strain from the piezoelectric body 61 for driving are propagated, and the output signal S2 includes the resonant signal and the static strain signal. The "static strain from the piezoelectric body 61 for driving" does not mean only the static strain of the piezoelectric body 61 for driving itself caused by the input of the drive signal S1, but means the static strain of the entire actuator device 1 propagated from the piezoelectric body 61 for driving to the piezoelectric body 71 for detection. Specifically, when the drive signal S1 is input and static strain is generated in the piezoelectric body 61 for driving, the static strain is propagated to the metal substrate 3 or the like, causing other members other than the piezoelectric body 61 for driving to be strained. Then, the static strain of the other members and the static strain of the piezoelectric body 61 for driving itself are propagated from the piezoelectric body 61 for driving to the piezoelectric body 71 for detection, and the piezoelectric body 71 for detection detects the output signal S2 including the static strain signal from the piezoelectric body 61 for driving. Therefore, in the actuator system 100, the control unit 20 generates an estimated static strain signal estimated to be included in the output signal S2, and executes a process of generating a resonant signal of the movable part 32 by subtracting the generated estimated static strain signal from the output signal S2. Thereby, the control unit 20 can generate an appropriate drive signal S1 for resonantly vibrating the movable part 32 based on the resonant signal of the movable part 32.

[0068] As shown in FIG. 1 , the control unit 20 includes a signal processing unit 201, a generating unit 202, an adjusting amplifier 203, an adjusting amplifier 204, and a differential amplifier 205. The signal processing unit 201 determines the amplitude and frequency of a drive signal S1 to be input to the actuator device 1. Specifically, the signal processing unit 201 determines the amplitude and frequency to maintain the resonant operation of the movable part 32 and bring the deflection angle of the movable part 32 closer to a target angle, based on a resonance signal S4 (details of which will be described later) acquired from the differential amplifier 205. The signal processing unit 201 is, for example, a microcontroller, an FPGA (Field Programmable Gate Array), or the like. The generating unit 202 generates a signal that serves as a base for the drive signal S1. The base signal has a frequency determined by the signal processing unit 201. The generating unit 202 is, for example, a DDS (Direct Digital Synthesizer), a VCO (Voltage-controlled oscillator), or the like. The adjustment amplifier 203 adjusts the signal generated by the generation unit 202 to have the amplitude determined by the signal processing unit 201. This generates a sinusoidal drive signal S1. The drive signal S1 is input to the input unit 91 of the connector 9.

[0069] The signal processing unit 201 also determines the amplitude and frequency of an estimated static strain signal estimated to be included in the output signal S2 based on the determined amplitude and frequency of the drive signal S1 and the signal data acquired by the preliminary inspection. The signal data indicates the voltage value of the static strain signal from the drive piezoelectric element 61 for each voltage value of the drive signal S1, and is stored in advance in, for example, a storage unit (not shown) included in the control unit 20. The generation unit 202 then generates a signal that serves as a base for the estimated static strain signal based on the amplitude and frequency determined by the signal processing unit 201. The base signal has a frequency determined by the signal processing unit 201. The adjustment amplifier 204 then adjusts the signal generated by the generation unit 202 so that it has the amplitude determined by the signal processing unit 201. As a result, a sinusoidal estimated static strain signal S3 is generated. The generated estimated static strain signal S3 is input to the differential amplifier 205.

[0070] The signal data used for generating the estimated static strain signal S3 is pre-acquired by an inspection process before shipment and / or a preliminary inspection performed at the time of activation of the actuator device 1. In the preliminary inspection, by driving the actuator device 1 at a frequency sufficiently lower than the resonance frequency of the movable part 32, the voltage value of the static strain signal from the piezoelectric body 61 for driving with respect to each voltage value of the drive signal is acquired. A frequency sufficiently lower than the resonance frequency of the movable part 32 is, for example, a value of 50% or less of the resonance frequency of the movable part 32. The resonance frequency of the movable part 32 is, for example, about 600 Hz. A frequency sufficiently lower than the resonance frequency of the movable part 32 is, for example, about 50 to 100 Hz. In the preliminary inspection, the actuator device 1 is driven at a frequency sufficiently lower than the resonance frequency of the movable part 32 (that is, the frequency of the drive signal input to the piezoelectric body 61 for driving is set to 50% or less of the resonance frequency of the movable part 32), and the output signal detected by the piezoelectric body 71 for detection is acquired as the static strain signal. That is, the static strain signal is a voltage signal detected by the piezoelectric body for detection when the frequency of the drive signal input to the piezoelectric body 61 for driving is 50% or less of the resonance frequency of the movable part 32. Thereby, the voltage value of the static strain signal from the piezoelectric body 61 for driving with respect to each voltage value of the drive signal S1 is acquired.

[0071] The differential amplifier 205 receives the estimated static strain signal S3 and the output signal S2 from the output part 93 of the connector 9. As described above, in the present embodiment, the movement of the piezoelectric body 61 for driving and the movement of the piezoelectric body 71 for detection coincide. Therefore, the differential amplifier 205 does not perform correction processing or the like for matching the generated estimated static strain signal S3 with the phase of the output signal S2, and generates the resonance signal S4 of the movable part 32 by subtracting the estimated static strain signal S3 from the output signal S2. The generated resonance signal S4 is input to the signal processing unit 201.

[0072] The control unit 20 further includes a drive signal generating unit 20A and an output signal processing unit 20B. The drive signal generating unit 20A generates a drive signal S1. The drive signal generating unit 20A is configured, for example, by a generating unit 202 and an adjusting amplifier 203. The output signal processing unit 20B processes the output signal S2. Specifically, the output signal processing unit 20B generates an estimated static strain signal S3 of the driving piezoelectric element 61 based on information regarding the frequency and amplitude of the drive signal S1, and generates a resonance signal S4 of the movable part 32 based on the output signal S2 and the estimated static strain signal S3. The output signal processing unit 20B is configured, for example, by an adjusting amplifier 204 and a differential amplifier 205. As described above, the control unit 20 generates an appropriate drive signal S1 for resonantly vibrating the movable part 32 based on the output signal S2 generated in the detecting piezoelectric element 71, and inputs the generated drive signal S1 to the actuator device 1. As a result, the appropriate drive signal S1 is input to the actuator device 1. [Action and effect]

[0073] In the actuator device 1, a driving piezoelectric element 61, a second electrode element 14, a detecting piezoelectric element 71, and a third electrode element 15 are stacked in this order on a first electrode element 13 provided on a metal substrate 3. In this way, the driving piezoelectric element 61 and the detecting piezoelectric element 71 are stacked on the same side of the metal substrate 3, which makes it less likely that variations will occur in the relative positional relationship between the driving piezoelectric element 61 and the detecting piezoelectric element 71. Therefore, the actuator device 1 and the actuator system 100 including the actuator device 1 can accurately detect the movement amount of the movable part 32.

[0074] For example, in a conventional example (hereinafter referred to as "Conventional Example 1") in which the driving piezoelectric element 61 is disposed on the main surface 31a of the metal substrate 3 and the detecting piezoelectric element 71 is disposed on the surface of the metal substrate 3 opposite to the main surface 31a, the driving piezoelectric element 61 and the detecting piezoelectric element 71 are each disposed with reference to the metal substrate 3. Therefore, the positional relationship between the driving piezoelectric element 61 and the detecting piezoelectric element 71 is likely to vary, and therefore the phase difference between the output signal S2 and the estimated static strain signal S3 is also likely to vary. Therefore, in Conventional Example 1, the resonance signal S4 obtained by subtracting the estimated static strain signal S3 from the output signal S2 deviates from the actual resonance signal corresponding to the actual swing angle (amplitude) and / or phase of the movable part 32, resulting in a deterioration in the accuracy of the resonance signal S4. Also, for example, in a conventional example (hereinafter referred to as "Conventional Example 2") in which the driving piezoelectric element 61 and the detecting piezoelectric element 71 are arranged on the main surface 31a of the metal substrate 3 so as not to overlap when viewed from the Z-axis direction, the driving piezoelectric element 61 and the detecting piezoelectric element 71 are each arranged with reference to the main surface 31a, and therefore the accuracy of the resonance signal S4 deteriorates for the same reason as in Conventional Example 1. Furthermore, in Conventional Example 2, because the driving piezoelectric element 61 and the detecting piezoelectric element 71 do not overlap, the phase difference between the output signal S2 and the estimated static strain signal S3 always varies, making it difficult to perform the process of subtracting the estimated static strain signal S3 from the output signal S2 or complicating the process of correcting the phase difference.

[0075] In contrast, in the actuator device 1, the driving piezoelectric element 61 and the detecting piezoelectric element 71 are stacked on the same side of the metal substrate 3. This makes it difficult for variation to occur in the positional relationship between the driving piezoelectric element 61 and the detecting piezoelectric element 71, and therefore makes it difficult for variation to occur in the phase difference between the output signal S2 and the estimated static strain signal S3. Therefore, by subtracting the estimated static strain signal S3 from the output signal S2, the resonance signal S4 can be obtained with high accuracy. Therefore, the actuator device 1 and the actuator system 100 can accurately detect the oscillation angle and phase, which are the operating amounts of the movable part 32.

[0076] Furthermore, in the actuator device 1, the driving piezoelectric element 61 and the detecting piezoelectric element 71 are arranged so that, when viewed from the Z-axis direction, the center points of the driving piezoelectric element 61 and the detecting piezoelectric element 71 coincide with each other. The driving piezoelectric element 61 is also arranged symmetrically with respect to both a line passing through the center point of the driving piezoelectric element 61 along the X-axis direction and a line passing through the center point of the driving piezoelectric element 61 along the Y-axis direction. The detecting piezoelectric element 71 is also arranged symmetrically with respect to both a line passing through the center point of the detecting piezoelectric element 71 along the X-axis direction and a line passing through the center point of the detecting piezoelectric element 71 along the Y-axis direction. This causes the movement of the driving piezoelectric element 61 and the movement of the detecting piezoelectric element 71 to coincide, resulting in the output signal S2 and the estimated static strain signal S3 being in phase with each other. This eliminates the need for, for example, a correction process to coincide the phase of the estimated static strain signal S3 with the phase of the output signal S2. The resonance signal S4 can be obtained by a simple process of simply subtracting the generated estimated static strain signal S3 from the output signal S2. Furthermore, since the movement of the driving piezoelectric element 61 coincides with the movement of the detecting piezoelectric element 71, the phases of the driving signal S1 and the estimated static strain signal S3 also coincide, eliminating the need for correction processing of the generated estimated static strain signal S3 and allowing the estimated static strain signal S3 to be generated by simple processing. In particular, an actuator device 1 using a metal substrate 3 is characterized by being more efficient to process and less expensive than actuator devices using silicon, and simplifying the circuit design is important in reducing the cost of the actuator device 1 as a whole.

[0077] Incidentally, even if in Conventional Example 1, the center point of the driving piezoelectric body 61 coincides with the center point of the detecting piezoelectric body 71, and the driving piezoelectric body 61 is line-symmetric with respect to the straight line passing through the center point of the driving piezoelectric body 61 along both the X-axis direction and the straight line passing through the center point of the driving piezoelectric body 61 along the Y-axis direction, and the detecting piezoelectric body 71 is line-symmetric with respect to the straight line passing through the center point of the detecting piezoelectric body 71 along both the X-axis direction and the straight line passing through the center point of the detecting piezoelectric body 71 along the Y-axis direction, even if alignment is performed, as with the reasons described above, in reality, variations in the relative positional relationship between the driving piezoelectric body 61 and the detecting piezoelectric body 71, and thus variations in the phase difference between the output signal S2 and the estimated static strain signal S3 occur, so the accuracy of the resonance signal S4 deteriorates, and it becomes difficult to accurately detect the rocking angle and phase of the movable part 32. Also, in the generation process of the estimated static strain signal S3, in Conventional Example 1, due to variations in the relative positional relationship between the driving piezoelectric body 61 and the detecting piezoelectric body 71, variations also occur in the phase difference between the driving signal S1 and the estimated static strain signal S3. As a result, the accuracy of the generated estimated static strain signal S3 deteriorates, making it even more difficult to accurately detect the rocking angle and phase of the movable part 32, or correction processing of the estimated static strain signal S3 becomes necessary, and the processing becomes complicated.

[0078] Also, in Conventional Example 1, the driving piezoelectric body 61 is disposed on the main surface 31a of the metal substrate 3, and the detecting piezoelectric body 71 is disposed on the surface opposite to the main surface 31a. Therefore, on the main surface 31a side, it is necessary to wire a wire from the electrode portion on the driving piezoelectric body side, and also on the surface opposite to the main surface 31a, wire a wire from the electrode portion on the detecting piezoelectric body 71 side, and the wiring structure becomes complicated. On the other hand, in the actuator device 1, since both the driving piezoelectric body 61 and the detecting piezoelectric body 71 are disposed on one side (main surface 31a side) with respect to the metal substrate 3, simplification of the wiring structure can be achieved.

[0079] Furthermore, in Conventional Example 1, the driving piezoelectric element 61 is disposed on the main surface 31a of the metal substrate 3, and the detecting piezoelectric element 71 is disposed on the surface opposite to the main surface 31a. In Conventional Example 2, both the driving piezoelectric element 61 and the detecting piezoelectric element 71 are disposed on the main surface 31a of the metal substrate 3 without overlapping. In contrast, in the actuator device 1, both the driving piezoelectric element 61 and the detecting piezoelectric element 71 are stacked on one side of the metal substrate 3, thereby reducing the space required for the metal substrate 3. Therefore, the actuator device 1 can be made smaller overall. Furthermore, when the voltage value of the static strain signal is acquired by driving the actuator device 1 at a frequency sufficiently lower than the resonant frequency of the movable part 32 in the above-mentioned preliminary inspection, if the voltage amplitude of the static strain signal is small, the voltage value of the static strain signal (calibration curve) may not be accurately obtained due to the influence of noise. In this regard, in the actuator device 1, the detecting piezoelectric element 71 is arranged on the driving piezoelectric element 61, so that the amplitude of the static strain signal (reference signal amplitude) can be made large, thereby improving the accuracy of the voltage value of the static strain signal and, ultimately, the control accuracy of the actuator device 1.

[0080] The actuator device 1 is disposed on a wiring board 2 and includes a connector 9 that houses a connection portion 92, an input portion 91, and an output portion 93. This allows for easy and reliable electrical connection between the first electrode portion 13, the second electrode portion 14, and the third electrode portion 15 and the control portion 20.

[0081] In the actuator device 1, when viewed from the Z-axis direction, the outer edge 71d of the detecting piezoelectric element 71 is located more inward than the outer edge 61d of the driving piezoelectric element 61. This makes it possible to position the detecting piezoelectric element 71 while visually checking the driving piezoelectric element 61 during manufacturing, thereby enabling more accurate alignment of the driving piezoelectric element 61 and the detecting piezoelectric element 71.

[0082] In the actuator device 1, the first electrode portion 13 has an electrode 63 arranged on the second main surface 61b, which allows a driving voltage to be applied uniformly to the second main surface 61b of the driving piezoelectric element 61, thereby improving driving efficiency.

[0083] The actuator device 1 includes a conductive adhesive member 4, the first electrode portion 13 further includes a conductive portion 30 and a conductive adhesive member 8A, the wiring board 2 includes an electrode pad 23 electrically connected to the input portion 91, the electrode pad 23 is provided on the mounting surface 2a of the wiring board 2, the adhesive member 4 bonds the metal substrate 3 and the electrode pad 23, and the adhesive member 8A bonds the electrode 63 and the conductive portion 30. This allows the first electrode portion 13 and the input portion 91 to be electrically connected simply and reliably.

[0084] In the actuator device 1, the second electrode portion 14 has an electrode 62 arranged on the first main surface 61a, which allows a driving voltage to be applied uniformly to the first main surface 61a of the driving piezoelectric element 61, thereby improving driving efficiency.

[0085] The actuator device 1 includes a wire 11, and the wiring board 2 has an electrode pad 21 electrically connected to the connection portion 92. The electrode pad 21 is provided on the mounting surface 2a of the wiring board 2, and the wire 11 is hung between the electrode 62 and the electrode pad 21. This allows the second electrode portion 14 and the connection portion 92 to be electrically connected simply and reliably.

[0086] In the actuator device 1, the electrode 62 includes a region 621 located outside the detecting piezoelectric element 71 when viewed from the Z-axis direction, and the wire 11 is hung between the region 621 and the electrode pad 21. This allows the second electrode portion 14, which is disposed between the driving piezoelectric element 61 and the detecting piezoelectric element 71, to be electrically connected to the connection portion 92 with a simple configuration.

[0087] In the actuator device 1, the second electrode portion 14 has an electrode 73 arranged on the fourth main surface 71b and a conductive adhesive member 8B, and the adhesive member 8B bonds the electrode 62 and the electrode 73. This makes it possible to input a desired drive signal S1 to the driving piezoelectric element 61 and to detect the output signal S2 generated in the detecting piezoelectric element 71 with high accuracy, with a simple configuration.

[0088] The actuator device 1 includes a wire 12, the third electrode portion 15 has an electrode 72 arranged on the third main surface 71a, the wiring board 2 has an electrode pad 22 electrically connected to the output portion 93, the electrode pad 22 is provided on the mounting surface 2a of the wiring board 2, and the wire 12 is stretched between the electrode 72 and the electrode pad 22. This allows the third electrode portion 15 and the output portion 93 to be electrically connected simply and reliably.

[0089] In the actuator device 1, the piezoelectric element on the metal substrate 3 side, which is arranged between the first electrode portion 13 and the second electrode portion 14, is the driving piezoelectric element 61, and the piezoelectric element on the opposite side of the metal substrate 3, which is arranged between the second electrode portion 14 and the third electrode portion 15, is the detecting piezoelectric element 71, the first electrode portion 13 is electrically connected to the input portion 91, and the third electrode portion 15 is electrically connected to the output portion 93. This makes it easier for the vibration of the driving piezoelectric element 61 to be properly propagated to the metal substrate 3, thereby achieving desired drive characteristics.

[0090] In the actuator system 100, the drive signal generation unit 20A generates a drive signal S1 for causing the movable part 32 to resonate, and the output signal processing unit 20B generates an estimated static strain signal S3 estimated to be included in the output signal S2 based on information about the frequency and amplitude of the drive signal S1, and generates a resonance signal S4 of the movable part 32 based on the output signal S2 and the estimated static strain signal S3. As a result, when the movable part 32 is resonated to drive the actuator device 1, the resonance signal S4 corresponding to the oscillation angle and phase of the movable part 32 can be accurately generated by subtracting the estimated static strain signal S3 from the output signal S2, and therefore the oscillation angle and phase of the movable part 32 can be accurately detected. [Variations]

[0091] The present invention is not limited to the above-described embodiment. For example, the first electrode unit 13 may be an electrode unit provided on the metal substrate 3. For example, the driving piezoelectric element 6 may not have an electrode 63, and the first electrode unit 13 may be composed of the adhesive member 8A and the conductive unit 30. Alternatively, the first electrode unit 13 may be composed of only the conductive unit 30. The second electrode unit 14 may be an electrode unit provided on the driving piezoelectric body 61. For example, the detecting piezoelectric element 7 may not have an electrode 73, and the second electrode unit 14 may be composed of the adhesive member 8B and the electrode 62 of the driving piezoelectric element 6. Alternatively, the driving piezoelectric element 6 may not have an electrode 62, and the second electrode unit 14 may be composed of the adhesive member 8B and the electrode 73 of the detecting piezoelectric element 7. Alternatively, the second electrode unit 14 may be composed of only the electrode 62 or only the electrode 73.

[0092] The shape of the wiring board 2 is not limited to that of the above embodiment. For example, instead of the opening, the wiring board 2 may have a recessed portion in the center, recessed on the opposite side of the mounting surface 2a from the metal substrate 3. Also, for example, instead of the opening, the wiring board 2 may have multiple pillars. Although the above embodiment illustrates the wiring board 2 supporting the metal substrate 3, the metal substrate 3 may be supported by a support member composed of one or more members. The positions of the electrode pads 21, 22, and 23 on the support member are not limited to those of the above embodiment. For example, the electrode pad 21 may be located in a region of the surface of the support member facing the metal substrate 3. Furthermore, for example, the electrode pad 22 may be located in a region of the surface of the support member on the side where the electrode 62 is located relative to the metal substrate 3 in the Z-axis direction, and the electrode pad 23 may be located in a region of the surface of the support member on the side where the electrode 72 is located relative to the metal substrate 3 in the Z-axis direction.

[0093] The drive piezoelectric element 6 and the detection piezoelectric element 7 may have opposite positional relationships and configurations. In the examples shown in FIGS. 6 and 7, the detection piezoelectric element 7 is fixed to the surface 30a of the conductive portion 30, and the drive piezoelectric element 6 is fixed on the detection piezoelectric element 7. The detection piezoelectric element 7 includes a detection piezoelectric body (first piezoelectric body, piezoelectric body on the other electrode portion side) 71, an electrode (second electrode) 72, and an electrode (first electrode) 73. The detection piezoelectric body 71 includes a third main surface (first main surface) 71a, a fourth main surface (second main surface) 71b, and side surfaces 71c. The drive piezoelectric element 6 includes a drive piezoelectric body (second piezoelectric body, piezoelectric body on one electrode portion side) 61, an electrode (fourth electrode) 62, and an electrode (third electrode) 63. The drive piezoelectric body 61 includes a first main surface (third main surface) 61a, a second main surface (fourth main surface) 61b, and side surfaces 61c.

[0094] The detection piezoelectric element 7 is disposed on the surface 30a of the conductive portion 30 such that a part of the main surface 31a of the metal substrate 3 is located outside the side surface 71c of the detection piezoelectric body 71. Thereby, a corner portion C1 is formed by a part of the main surface 31a and the side surface 71c of the detection piezoelectric body 71. The part of the main surface 31a is the portion outside the side surface 71c of the main surface 31a. The first portion 81 of the adhesive member 8A is disposed between the surface 30a of the conductive portion 30 and the detection piezoelectric element 7, and the second portion 82 is continuous from the first portion 81 and is disposed at the corner portion C1. The second portion 82 is in contact with the side surface 71c of the detection piezoelectric body 71 and a part of the main surface 31a. At least a part of the second portion 82 reaches the region on the side of the electrode 72 in the side surface 71c of the detection piezoelectric body 71. Also, the second portion 82 does not reach the outer edge 711 of the third main surface 71a.

[0095] The driving piezoelectric element 6 is disposed on the surface 72a of the electrode 72 so that a portion of the surface 72a is located outside the side surface 61c of the driving piezoelectric body 61. The surface 72a is the main surface of the electrode 72 opposite the detection piezoelectric body 71. As a result, a corner C2 is formed by a portion of the surface 72a of the electrode 72 and the side surface 61c of the driving piezoelectric body 61. A portion of the surface 72a is located outside the side surface 61c of the surface 72a. A third portion 83 of the adhesive member 8B is disposed between the surface 72a of the electrode 72 and the driving piezoelectric element 6, and a fourth portion 84 is continuous with the third portion 83 and disposed in the corner C2. The fourth portion 84 contacts the side surface 61c of the driving piezoelectric body 61 and a portion of the surface 72a of the electrode 72. At least a portion of the fourth portion 84 extends to a region of the side surface 61c of the driving piezoelectric body 61 on the electrode 62 side. Moreover, the fourth portion 84 does not reach the outer edge 611 of the first main surface 61a.

[0096] The width of the driving piezoelectric element 61 in the X-axis direction is smaller than the width of the detecting piezoelectric element 71 in the X-axis direction, and the width of the driving piezoelectric element 61 in the Y-axis direction is smaller than the width of the detecting piezoelectric element 71 in the Y-axis direction. Furthermore, when viewed from the Z-axis direction, the outer edge 61d of the driving piezoelectric element 61 is located inside the outer edge 71d of the detecting piezoelectric element 71.

[0097] As shown in Fig. 7, the first electrode portion 13 is provided on the metal substrate 3. The first electrode portion 13 has a conductive portion 30, an adhesive member 8A, and an electrode 73 of the piezoelectric element 7 for detection. In this modification, the first electrode portion 13 is composed of the conductive portion 30, at least a part of the adhesive member 8A, and the electrode 73 of the piezoelectric element 7 for detection. In the first electrode portion 13, the electrode 73 and the conductive portion 30 are adhered by the adhesive member 8A. A piezoelectric body 71 for detection is disposed on the first electrode portion 13. The second electrode portion 14 is disposed on the third main surface 71a of the piezoelectric body 71 for detection. The third main surface 71a is the main surface on the side opposite to the first electrode portion 13, and the fourth main surface 71b is the main surface on the side of the first electrode portion 13. The second electrode portion 14 has an electrode 72 of the piezoelectric element 7 for detection, an adhesive member 8B, and an electrode 63 of the piezoelectric element 6 for driving. In this modification, the second electrode portion 14 is composed of the electrode 72, at least a part of the adhesive member 8B, and the electrode 63. In the second electrode portion 14, the electrode 72 and the electrode 63 are adhered by the adhesive member 8B. A piezoelectric body 61 for driving is disposed on the second electrode portion 14. The third electrode portion 15 is disposed on the first main surface 61a of the piezoelectric body 61 for driving. The first main surface 61a is the main surface on the side opposite to the second electrode portion 14, and the second main surface 61b is the main surface on the side of the second electrode portion 14. The third electrode portion 15 has an electrode 62 of the piezoelectric element 6 for driving. In this modification, the third electrode portion 15 is composed of the electrode 62. As described above, the piezoelectric body 71 for detection is disposed between the first electrode portion 13 and the second electrode portion 14, and the piezoelectric body 61 for driving is disposed between the second electrode portion 14 and the third electrode portion 15.

[0098] The first electrode unit 13 is electrically connected to the output unit 93 of the connector 9 via the metal substrate 3, the adhesive member 4, the electrode pad 23, the wiring of the wiring board 2, and the terminal 90a. The second electrode unit 14 is electrically connected to the connection unit 92 of the connector 9 via the wire 11 that is hung between a region 721 on the surface 72a of the electrode 72 and the electrode pad 21, the electrode pad 21, the wiring of the wiring board 2, and the terminal 90b. As shown in FIG. 6 , the region 721 is a region of the surface 72a of the electrode 72 that is located outside the driving piezoelectric element 61 when viewed from the Z-axis direction. The third electrode unit 15 is electrically connected to the input unit 91 of the connector 9 via the wire 12, the electrode pad 22, the wiring of the wiring board 2, and the terminal 90c. In this modification, the driving piezoelectric element 61 and the detecting piezoelectric element 71 are stacked on the same side of the metal substrate 3, which reduces variation in the relative positional relationship between the driving piezoelectric element 61 and the detecting piezoelectric element 71, thereby achieving the same effect as the above embodiment. In this modification, the second electrode portion 14 has an electrode 63 arranged on the second main surface 61b, which allows a driving voltage to be applied uniformly to the second main surface 61b of the driving piezoelectric element 61, thereby improving driving efficiency.

[0099] In the above embodiment, the optical function unit 5 has the optical surface 51, which is a mirror surface. However, the optical function unit 5 may be, for example, a reflective diffraction grating, a transmissive diffraction grating, an optical filter, or the like. The actuator device 1 may include the wiring substrate 2, the metal substrate 3, the first electrode unit 13, the driving piezoelectric element 61, the second electrode unit 14, the detecting piezoelectric element 71, the third electrode unit 15, the input unit 91, the connection unit 92, and the output unit 93. For example, the actuator device 1 may not include the connector 9, the wires 11 and 12, the adhesive members 8A, and the adhesive members 8B. When the actuator device 1 does not include the connector 9, for example, the input unit 91, the connection unit 92, and the output unit 93 may each be directly provided on the wiring substrate 2 and connected to the control unit 20 via wires or the like. In the above embodiment, the first connecting portion 35 connects the movable portion 32 and the main body portion 31 via the first extension portion 33. However, the first connecting portion 35 may directly connect the movable portion 32 and the main body portion 31. Similarly, in the above embodiment, the second connecting portion 36 connects the movable portion 32 and the main body portion 31 via the second extension portion 34. However, the second connecting portion 36 may directly connect the movable portion 32 and the main body portion 31. Furthermore, the metal substrate 3 may have the movable portion 32, the main body portion 31 provided with the first electrode portion 13, and a connecting portion connecting the movable portion 32 and the main body portion 31. For example, the metal substrate 3 may not have the first connecting portion 37, the second connecting portion 38, and the third connecting portion 39. A portion of the main body portion 31 of the metal substrate 3 faces a portion of the wiring board 2, and the portion of the main body portion 31 and the portion of the wiring board 2 may be bonded by the adhesive member 4.

[0100] Also, when viewed from the Z-axis direction, the driving piezoelectric body 61 and the detecting piezoelectric body 71 do not have to be arranged such that the center point of the driving piezoelectric body 61 coincides with the center point of the detecting piezoelectric body 71. Further, the driving piezoelectric body 61 does not have to be arranged to be line-symmetric with respect to the straight line passing through the center point of the driving piezoelectric body 61 along the X-axis direction or the straight line passing through the center point of the driving piezoelectric body 61 along the Y-axis direction. The detecting piezoelectric body 71 also does not have to be arranged to be line-symmetric with respect to the straight line passing through the center point of the detecting piezoelectric body 71 along the X-axis direction or the straight line passing through the center point of the detecting piezoelectric body 71 along the Y-axis direction. Further, the shape of each of the driving piezoelectric body 61 and the detecting piezoelectric body 71 is not limited, and may be, for example, a shape that is not line-symmetric. In that case, for example, in the control unit 20, before the process of subtracting the estimated static strain signal S3 from the output signal S2, a correction process for matching the phase of the output signal S2 and the phase of the estimated static strain signal S3 may be performed. Further, the driving signal input to the driving piezoelectric body 61 does not have to be a signal for resonantly operating the movable part.

[0101] The configurations of the driving signal generation unit 20A and the output signal processing unit 20B of the control unit 20 are not limited to the above-described embodiment. The driving signal generation unit 20A only needs to generate the driving signal S1, and may be configured, for example, only by the generation unit 202, or may be configured, for example, by other components included in the control unit 20. The output signal processing unit 20B only needs to generate the estimated static strain signal S3 based on the information regarding the frequency and amplitude of the driving signal S1, and generate the resonance signal S4 based on the output signal S2 and the estimated static strain signal S3, and may be configured, for example, only by the differential amplifier 205, or may be configured, for example, by other components included in the control unit 20.

[0102] The driving piezoelectric body 61 may be any piezoelectric body for operating the movable part 32, and the detecting piezoelectric body 71 may be any piezoelectric body for detecting the amount of movement. For example, in the actuator device 1, in addition to the mode in which torsional vibration (torsional resonance) is induced in the first connecting part 35 and the second connecting part 36 and the movable part 32 and the optical surface 51 swing around the X axis (hereinafter referred to as the "first resonance mode"), or instead of the first resonance mode, there may be a second resonance mode. In the second resonance mode, due to the generation of periodic plate waves, the first connecting part 35 and the second connecting part 36 move (translate) along the Z-axis direction, and the movable part 32 and the optical surface 51 move along the Z-axis direction. In the second resonance mode, the displacement amount and phase of the optical surface 51 may be detected, and the output signal S2 may be a voltage signal corresponding to the changes in the displacement amount and phase due to the movement of the movable part 32 and the optical surface 51. Also, in the second resonance mode, the resonance signal S4 may be a voltage signal corresponding to the displacement amount and phase of the movable part 32. Thereby, even in the second resonance mode, since a resonance signal corresponding to the displacement amount and phase of the movable part 32 can be accurately generated, the displacement amount and phase of the movable part 32 can be accurately detected.

Explanation of Signs

[0103] 1...actuator device, 2...wiring board (support), 2a...mounting surface, 3...metal substrate, 4...adhesive member (first adhesive member), 8A...adhesive member (second adhesive member), 8B...adhesive member (third adhesive member), 9...connector, 11...wire (first wire), 12...wire (second wire), 13...first electrode portion, 14...second electrode portion, 15...third electrode portion, 20...control unit (outside of actuator device 1), 20A...drive signal generating unit, 20B...output signal processing unit, 21...electrode pad (second electrode pad), 22...electrode pad (third electrode pad), 23...electrode pad (first electrode pad), 30...conductive portion, 30a...surface, 31...main body portion, 31a...main surface, 32...movable portion, 35... First connecting portion (connecting portion), 36...second connecting portion (connecting portion), 61...driving piezoelectric element (first piezoelectric element, second piezoelectric element), 61a...first main surface (third main surface), 61b...second main surface (fourth main surface), 61d, 62c, 71d, 72c...outer edge, 62, 72...electrodes (second electrode, fourth electrode), 62a, 72a...surface, 63, 73...electrodes (first electrode, third electrode), 71...detecting piezoelectric element (first piezoelectric element, second piezoelectric element), 71a...third main surface (first main surface), 71b...fourth main surface (second main surface), 91...input portion, 92...connecting portion, 93...output portion, 100...actuator system, 621, 721...area, S1...driving signal, S2...output signal, S3...estimated static strain signal, S4...resonance signal.

Claims

1. a support; a metal substrate supported by the support; a first electrode portion provided on the metal substrate; a first piezoelectric body disposed on the first electrode portion, having a first main surface on the side opposite to the first electrode portion and a second main surface on the side of the first electrode portion; a second electrode portion disposed on the first main surface; a second piezoelectric body disposed on the second electrode portion, having a third main surface on the side opposite to the second electrode portion and a fourth main surface on the side of the second electrode portion; a third electrode portion disposed on the third main surface; a connection portion electrically connected to the second electrode portion; an input portion electrically connected to one of the first electrode portion and the third electrode portion; an output portion electrically connected to the other of the first electrode portion and the third electrode portion, comprising: the metal substrate has a movable portion; a main body portion provided with the first electrode portion; a connecting portion connecting the movable portion and the main body portion; one of the first piezoelectric body and the second piezoelectric body on the side of the electrode portion is a driving piezoelectric body for operating the movable portion; the other of the first piezoelectric body and the second piezoelectric body on the side of the electrode portion is a detection piezoelectric body for detecting the operation amount of the movable portion; the connection portion is configured to be electrically connected to an external reference potential so that the potential of the second electrode portion becomes the reference potential; the input portion is configured to input a driving signal for driving the driving piezoelectric body from the outside to the one electrode portion; the output portion is configured to output an output signal generated in the detection piezoelectric body from the other electrode portion to the outside, an actuator device.

2. The actuator device according to claim 1, further comprising a connector disposed on the support and accommodating the connection portion, the input portion, and the output portion.

3. The actuator device according to claim 1 or 2, wherein when viewed from the thickness direction of the metal substrate, an outer edge of the second piezoelectric body is located inside an outer edge of the first piezoelectric body.

4. The actuator device according to any one of claims 1 to 3, wherein the first electrode portion has a first electrode disposed on the second main surface.

5. further comprising a first adhesive member having conductivity; the first electrode portion further has a conductive portion integrally formed with the metal substrate and a second adhesive member having conductivity; the support has a first electrode pad electrically connected to the input portion or the output portion. The first electrode pad is located in a region of the surface of the support facing the metal substrate. The first adhesive member adheres the metal substrate and the first electrode pad. The actuator device according to claim 4, wherein the second adhesive member adheres the first electrode and the conductive portion.

6. The actuator device according to any one of claims 1 to 5, wherein the second electrode portion has a second electrode disposed on the first main surface.

7. Further comprising a first wire, The support has a second electrode pad electrically connected to the connection portion, The second electrode pad is located in a region of the surface of the support on the side where the second electrode is disposed with respect to the metal substrate in the thickness direction of the metal substrate. The actuator device according to claim 6, wherein the first wire is stretched between the second electrode and the second electrode pad.

8. The second electrode includes a region located outside the second piezoelectric body when viewed in the thickness direction of the metal substrate, The actuator device according to claim 7, wherein the first wire is stretched between the region of the second electrode and the second electrode pad.

9. The actuator device according to any one of claims 6 to 8, wherein the second electrode portion further has a third electrode disposed on the fourth main surface.

10. The second electrode portion further has a third adhesive member having conductivity, The actuator device according to claim 9, wherein the third adhesive member adheres the second electrode and the third electrode.

11. Further comprising a second wire, The third electrode portion has a fourth electrode disposed on the third main surface, The support has a third electrode pad electrically connected to the input portion or the output portion, The third electrode pad is located in a region of the surface of the support on the side where the fourth electrode is disposed with respect to the metal substrate in the thickness direction of the metal substrate. The actuator device according to any one of claims 1 to 10, wherein the second wire is stretched between the fourth electrode and the third electrode pad.

12. The first piezoelectric body is the driving piezoelectric body, The second piezoelectric body is the detection piezoelectric body, The first electrode portion is electrically connected to the input portion, The actuator device according to any one of claims 1 to 11, wherein the third electrode portion is electrically connected to the output portion.

13. The actuator device according to any one of claims 1 to 12, and a control unit electrically connected to the input unit and the output unit of the actuator device, comprising: The control unit is a drive signal generation unit that generates the drive signal, and an output signal processing unit that processes the output signal, an actuator system.

14. The drive signal generation unit generates the drive signal for resonantly operating the movable part, The output signal processing unit generates an estimated static strain signal estimated to be included in the output signal based on information regarding the frequency and amplitude of the drive signal, and generates a resonance signal of the movable part based on the output signal and the estimated static strain signal. The actuator system according to claim 13.

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