JP2006067706A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator that can obtain a large drive force and has a large swing angle (swing width). <P>SOLUTION: The actuator of a two-freedom vibration type comprises a first mass 2; second masses 1, 11; piezoelectric elements 53, 55; vibrating bodies 7 that vibrate by being driven by the application of AC voltages to the piezoelectric elements 53, 55; supports 3 that support the first mass 2 and the second masses 1, 11; a pair of first elastic connecting parts 5, 5 that connect the first mass 2 and the second masses 1, 11, so that the first mass 2 is turnable with respect to the second masses 1, 11; and a pair of second elastic connecting parts 4, 4 that connect the second masses 1, 11 and the supports 3, so that the second masses 1, 11 are turnable with respect to the supports 3. The second masses 1, 11 are driven by vibrations of the vibrating bodies 7, 7, respectively, and the first mass 2 is turned accompanied by the drive. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an actuator.

For example, a polygon mirror (rotating polyhedron) is known as an actuator used in a laser printer or the like.
However, in such a polygon mirror, in order to achieve high-quality, high-quality printing and high-speed printing, the polygon mirror must be rotated at a higher speed. In current polygon mirrors, air bearings are used to maintain high-speed and stable rotation, but it is difficult to obtain higher-speed rotation. In addition, in order to increase the speed, a large motor is required, and there are problems that noise, heat generation, power consumption are large, and miniaturization is difficult. When such a polygon mirror is used, there is a problem that the structure becomes complicated and the cost becomes high.

Further, a one-degree-of-freedom torsional vibrator in which electrodes are arranged in a parallel plate shape as shown in FIG. 13 has been proposed from the early stage of research on actuators because of its simple structure (for example, Non-Patent Document 1 reference). In addition, an electrostatic drive type vibrator in which the torsional vibrator is a cantilever type has been proposed (see, for example, Non-Patent Document 2).
The electrostatic drive type torsional vibrator shown in FIG. 13 fixes both ends fixing portions 300a of a movable electrode plate 300 made of a silicon single crystal plate to both ends on a glass substrate 1000 via a spacer 200. A fixed electrode 400 that supports the movable electrode portion 300c between the fixed end portions 300a of the plate 300 via a narrow torsion bar 300b and is opposed to the movable electrode portion 300c with an electrode interval is provided on the glass substrate 1000. Above, it is arranged in parallel to the movable electrode part 300c. A power source 500 is connected between the movable electrode plate 300 and the fixed electrode 400 via a switch 600.

  In the torsional vibrator having the above-described configuration, when a voltage is applied between the movable electrode portion 300c and the fixed electrode 400, the movable electrode portion 300c rotates about the torsion bar 300b as an axis by electrostatic attraction. However, in the structure described above, since the movable electrode portion 300c serves as both the electrode and the movable portion, if the electrode interval is narrowed to obtain a large driving force, the displacement (rotation angle) is restricted, and the movable range is increased. When the electrode interval is increased, the driving force is weakened. For this reason, there is a problem that it is difficult to obtain a large driving force and a large amplitude.

K.E.Petersen: “Silicon Torsional Scanning Mirror”, IBM J. Res. Development., Vol. 24 (1980), p. 631 Kawamura et al .: “Research of micromechanics using Si”, Proceedings of the 1986 Fall Meeting of the Japan Society for Precision Engineering, p.753

  An object of the present invention is to provide an actuator capable of obtaining a large driving force and having a large deflection angle (amplitude).

Such an object is achieved by the present invention described below.
The actuator of the present invention includes a first mass part,
A second mass part;
A vibrating body that includes a piezoelectric element and is driven and vibrated by applying an AC voltage to the piezoelectric element;
A support part for supporting the first mass part and the second mass part;
At least one pair of first elastic members that connect the first mass unit and the second mass unit so that the first mass unit is rotatable with respect to the second mass unit. A connecting portion;
And having at least one pair of second elastic connecting portions for connecting the second mass portion and the support portion so that the second mass portion is rotatable with respect to the support portion. ,
The second mass unit is driven by the vibration of the vibrating body, and the first mass unit rotates accordingly.

  Accordingly, since the second mass unit can be easily and reliably driven with a large driving force and a large rotation angle (swing angle), an actuator having a large rotation angle (swing angle) of the first mass unit can be obtained. Can be provided. In addition, the first mass unit can be driven at a high frequency. In addition, since the structure can be simplified, high integration, high density, and low cost can be achieved.

The actuator of the present invention includes a first mass part,
A pair of second mass parts respectively provided on one end side and the other end side of the first mass part via the first mass part;
A support part for supporting the first mass part and the second mass parts;
A vibrating body that includes a piezoelectric element and is driven and vibrated by applying an AC voltage to the piezoelectric element;
At least one pair of first masses connecting the first mass parts and the second mass parts so that the first mass parts are rotatable with respect to the second mass parts. An elastic connecting portion of
At least one pair of second elastic connecting portions that connect each of the second mass portions and the support portion such that each of the second mass portions is rotatable with respect to the support portion; Have
The second mass portions are driven by the vibration of the vibrating body, and the first mass portions are rotated accordingly.

  Accordingly, the second mass unit can be easily and reliably driven with a large driving force and a large rotation angle (runout angle). In addition, since the rotation angle of the first mass unit is not limited to the rotation angle of the second mass unit, an actuator having a larger rotation angle (swing angle) of the first mass unit can be provided. In addition, since the structure can be simplified, high integration, high density, and low cost can be achieved.

In the actuator of the present invention, the actuator has a plurality of the vibrators,
It is preferable that the vibrating bodies are respectively provided at portions corresponding to the pair of second mass parts.
Thus, the corresponding pair of second mass parts can be driven easily and reliably.

In the actuator according to the aspect of the invention, it is preferable that the vibrating body is configured to be able to drive the pair of second mass parts in synchronization with each other.
Thereby, control of a pair of 2nd mass parts can be simplified.
In the actuator of the present invention, the vibrating body has a bimorph structure,
It is preferable that the vibrating body is configured to transmit a driving force to the second mass unit by a bending displacement of the piezoelectric element.
Thereby, since a big displacement amount can be given with respect to a 2nd mass part, a 2nd mass part can be driven with a bigger rotation angle (deflection angle).

In the actuator of the present invention, each of the vibrating body and the second mass unit has a long plate shape,
It is preferable that one end portion of the vibrating body and one end portion of the second mass portion are provided so as to overlap in a plan view.
Thereby, the second mass unit can be driven with a large driving force with a simple configuration.

In the actuator according to the aspect of the invention, it is preferable that the other end portion of the vibrating body is fixed to the support portion.
Thereby, the second mass unit can be stably driven with a simple configuration. Moreover, the displacement of the vibrating body can be increased. Further, the entire apparatus can be reduced in size.
In the actuator of the present invention, comprising an opposing substrate provided to face the support portion,
It is preferable that the other end of the vibrating body is fixed to the counter substrate.
Thereby, the second mass unit can be stably driven with a simple configuration.

In the actuator of the present invention, the counter substrate is provided with a recess,
It is preferable that the other end of the vibrating body is inserted and fixed in the recess.
As a result, the second mass unit can be stably driven more reliably.
In the actuator of the present invention, a protrusion is provided on one or both of the one end of the vibrating body and the one end of the second mass unit,
It is preferable that the vibrating body is configured to transmit a driving force to the second mass unit via the protrusion.
Thereby, simplification of the control of the vibration of the second mass unit can be achieved.

In the actuator according to the aspect of the invention, it is preferable that the second mass unit and the vibrating body are coupled in advance.
Thereby, the contact area of a vibrating body and a 2nd mass part can be made small, and the loss of vibration can be made small. In addition, the second mass unit can be easily and reliably driven at a desired frequency.

The actuator according to the aspect of the invention preferably includes a displacement measuring unit that measures the displacement of the first mass unit or the second mass unit when the vibrating body vibrates.
Thereby, for example, the rotation angle of the second mass part can be detected, and the detection result can be used for controlling the deflection angle of the first mass part.
In the actuator according to the aspect of the invention, it is preferable that the displacement measuring unit includes a piezoresistive element provided in at least one of the pair of first elastic coupling portions and the pair of second elastic coupling portions. .
Thereby, the structure can be simplified.

In the actuator according to the aspect of the invention, it is preferable that the displacement measuring unit can detect the displacement in a non-contact manner with respect to the first mass portion and the second mass portion.
Thereby, the structure can be simplified.
The actuator of the present invention is preferably configured to control an angle of rotation of the first mass part with respect to the first elastic coupling part based on detection of the displacement measuring means.
Thereby, since the displacement amount of a vibrating body can be controlled reliably, the rotation angle (deflection angle) of a 2nd mass part can be made into a desired thing. Thereby, the deflection angle of the first mass part can be suitably controlled.

In the actuator according to the aspect of the invention, the vibration of the vibrating body is controlled so that the frequency of the AC voltage is equal to a resonance frequency of a two-degree-of-freedom vibration system in which the second mass portion and the first mass portion resonate. It is preferable to do.
Thereby, the rotation angle (swing angle) of the first mass unit can be increased while suppressing the amplitude of the second mass unit.
The first mass part preferably has a light reflecting part.
Thereby, when the actuator of this invention is used as an optical scanner, for example, the optical path of light can be changed easily.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an actuator of the invention will be described with reference to the accompanying drawings.
First, a first embodiment of the actuator of the present invention will be described.
FIG. 1 is a plan view showing a first embodiment of the actuator of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a plan view showing a counter substrate of the first embodiment. 4 is a cross-sectional view taken along line BB in FIG. 1, and FIG. 5 is a side view of a vibrating body (bimorph type piezoelectric element). In the following, for convenience of explanation, the upper side in FIG. 1 is referred to as “upper”, the lower side as “lower”, the right side as “right”, and the left side as “left”.

An actuator 100 shown in FIG. 1 includes a first mass part (movable part) 2, a pair of second mass parts (drive parts) 1, 11 having a rectangular long plate shape, and a support part 3. A substrate 6 and a pair (a plurality) of vibrating bodies 7 having a rectangular long plate shape are included.
In the actuator 100, the first mass unit 2 is located at the center, the second mass unit 1 is provided on one end side (right side) via the first mass unit 2, and the second mass unit 11 is the other. It is provided on the end side (left side). Moreover, the support part 3 is arrange | positioned at the right side in FIG. 1 of the 2nd mass part 1, and the left side in FIG. 1 of the 2nd mass part 11, respectively.

In the present embodiment, the second mass parts 1 and 11 have substantially the same shape and the same dimensions, and are provided substantially symmetrically via the first mass part 2.
The second mass parts 1, 11, the first mass part 2, and the support part 3 are each made of, for example, silicon.
A light reflecting portion 21 is provided on the surface of the first mass portion 2 of this embodiment (the surface opposite to the side on which the counter substrate 6 is provided).

  In addition, as shown in FIG. 1, the actuator 100 includes a second mass unit 1, 11 provided on the left side of the support unit 3 provided on the right side of the second mass unit 1 and the second mass unit 11, respectively. A pair of second elastic connecting portions 4, 4 that connect the second mass portions 1, 11 and the support portion 3 are provided so as to be rotatable with respect to the supported support portion 3. In addition, a pair of the second mass units 1 and 11 and the first mass unit 2 are connected so that the first mass unit 2 can be rotated with respect to the second mass units 1 and 11. The first elastic connecting portions 5 and 5 are provided. That is, the first mass part 2 is connected to the second mass parts 1 and 11 via the first elastic coupling parts 5 and 5, respectively, and the second mass parts 1 and 11 are respectively connected to the second elastic parts 1 and 11. It is connected to the supporting part 3 on the corresponding side (right side, left side) via connecting parts 4, 4. Further, the second elastic connecting portion 4 and the first elastic connecting portion 5 are provided coaxially, and these serve as a rotation center axis (rotating axis) 41.

The support part 3 is joined to the counter substrate 6 as shown in FIG.
The counter substrate 6 is made of various types of glass or silicon.
As shown in FIGS. 2 and 3, the counter substrate 6 has an opening 61 at a position corresponding to the first mass portion 2.
As shown in FIGS. 3 and 4, recesses 62 and 62 are formed on the upper surface of the counter substrate 6 at portions corresponding to the second mass portions 1 and 11. Further, on the upper surface of the counter substrate 6, recesses 71 and 71 having a depth smaller than the recesses 62 and 62 are formed below the recesses 62 and 62 in FIG. 1.

  As shown in FIG. 2, end portions (the other end portions) 17 and 17 of the vibrating bodies 7 and 7 are inserted and fixed in the recesses 71 and 71. Further, the end portions (one end portion) 18, 18 of the vibrating bodies 7, 7 are the end portions (lower end portions in FIG. 1) 14, 14 of the second mass portions 1, 11, respectively. It is located in the lower part in FIG. That is, the end portions 14 and 14 of the second mass portions 1 and 11 and the end portions 18 and 18 of the vibrating bodies 7 and 7 are installed so as to overlap each other in plan view.

These vibrating bodies 7 and 7 are installed so as to be substantially line symmetric with respect to the first mass portion 2.
In addition, it is preferable that the site | part which overlaps in planar view each of the edge parts 14 and 14 of the 2nd mass parts 1 and 11 and the edge parts 18 and 18 of the vibrating bodies 7 and 7 is as small as possible. By doing so, the vibrations of the vibrating bodies 7 and 7 are efficiently transmitted to the second mass parts 1 and 11.

As shown in FIG. 4, projections 51, 51 as vibration transmission bodies are formed on the second mass parts 1, 11. The second mass parts 1 and 11 and the vibrating bodies 7 and 7 are coupled via these protrusions 51 and 51.
The protrusion 51 may not be provided.
Since the configurations and functions of the vibrating bodies 7 and 7 are the same as each other, the right-side vibrating body 7 in FIG.

  As shown in FIG. 5, the vibrating body 7 includes a first electrode 52, a first piezoelectric element 53 as an electric / mechanical conversion element (first electric / mechanical conversion element), a third electrode 54, and the like. The second piezoelectric element 55 as the electric / mechanical conversion element (second electric / mechanical conversion element) and the second electrode 56 are sequentially stacked. The first electrode 52, the first piezoelectric element 53, the third electrode 54, the second piezoelectric element 55, and the second electrode 56 constitute the vibrating body 7 having a bimorph structure. Therefore, in the following description, the vibrating body 7 may be referred to as a “bimorph piezoelectric element 7”.

The first electrode 52 and the second electrode 56 are electrically connected to each other by, for example, a conducting wire or the like, thereby constituting a group electrode 57. The third electrode 54 and the group electrode 57 are connected to a drive circuit described later.
Here, when an AC voltage from the third electrode 54 and the group electrode 57 is applied to the first piezoelectric element 53 and the second piezoelectric element 55, the first piezoelectric element 53 has a rectangular shape. The first piezoelectric element 53 contracts in the longitudinal direction A.

On the other hand, the second piezoelectric element 55 extends in the longitudinal direction B of the rectangular second piezoelectric elements 53 and 55. As a result, the vibrating body 7 is bent and displaced in the direction C in FIG. 5 of the first and second piezoelectric elements 53 and 55.
When the actuator 100 described later is used, the second mass parts 1 and 11 are pressed and driven by the bending displacement of the vibrating body 7.

The constituent materials of these piezoelectric elements 53 and 55 are not particularly limited. For example, lead zirconate titanate (PZT), crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, Various types such as lead zinc niobate and lead scandium niobate are preferably used.
In the two-degree-of-freedom vibration type actuator configured as described above, the first vibration system including the first mass portion 2 and the first elastic coupling portion 5, the second mass portions 1 and 11, and the second mass portion. And a second vibration system composed of the elastic connecting portion 4.

  In addition, the actuator 100 according to the present embodiment includes at least one of the pair of second elastic coupling portions 4 and the pair of first elastic coupling portions 5. In the present embodiment, the first mass in FIG. The left first elastic coupling portion 5 with respect to the portion 2 includes a piezoresistive element (displacement measuring means) 42 therein. A detection signal indicating the rotation angle (displacement angle) of the second mass parts 1 and 11 is output from the piezoresistive element.

  In addition, the actuator 100 is provided with a control unit and a storage unit (not shown). The piezoresistive elements 42 are electrically connected to the control means, respectively, and a detection signal (detection value) from the piezoresistive elements 42 is input to the control means as needed. Further, the relationship (calibration curve) between the detection signal and the deflection angle of the first mass unit 2 is stored in the storage unit in advance as a table. The calibration curve may be a table or a mathematical formula.

  When the actuator 100 of this embodiment is used, an AC voltage is applied between the third electrode 54 and the group electrode 57 of the vibrating bodies 7 and 7. As a result, an alternating voltage is applied to the first piezoelectric element 53 and the second piezoelectric element 55, the first piezoelectric element 53 contracts and the second piezoelectric element 55 expands, whereby the vibrating bodies 7, 7. However, it bends and displaces upward in FIG. 2 to press the second mass parts 1 and 11 and transmit a driving force to the second mass parts 1 and 11. By this driving force, the second mass parts 1 and 11 rotate by a predetermined angle around the rotation center axis 41 (second elastic coupling part 4). As the second mass parts 1 and 11 rotate, the first mass part 2 connected via the first elastic connection part 5 is connected to the rotation center shaft 41 (first elastic connection part 5). ) Around a predetermined angle.

  Thereafter, due to the change in the amplitude of the AC voltage, the driving force to the second mass parts 1 and 11 of the vibrating body 7 changes, and the second mass parts 1 and 11 are connected to the rotation center shaft 41 (second elastic connection). It vibrates (rotates) around the part 4). Along with the vibrations of the second mass portions 1 and 11, the first mass portion 2 connected via the first elastic connecting portion 5 is connected to the rotation center shaft 41 (first elastic connecting portion 5). ) Around a predetermined angle.

For example, when the control unit receives a command to vibrate the first mass unit 2 at a predetermined deflection angle, the control unit generates the first mass by using the detection signal from the piezoresistive element 42 and, for example, the calibration curve described above. The deflection angle of the unit 2 is obtained and an instruction is given to the drive circuit described above. The drive circuit changes the amplitude of the AC voltage applied to the piezoelectric elements 53 and 55 in accordance with an instruction from the control means. Thereby, the 1st mass part 2 can be driven with a desired deflection angle.
In this actuator 100, the frequency of the AC voltage applied to the bimorph piezoelectric element 7 is equal to the resonance frequency of the two-degree-of-freedom vibration system in which the second mass parts 1, 11 and the first mass part 2 resonate. It is preferable to set to. Thereby, the rotation angle (swing angle) of the first mass unit can be increased while suppressing the amplitude of the second mass unit.

Here, the distance (length) between the end portion 12 in the direction (longitudinal direction) substantially perpendicular to the rotation center axis 41 of the second mass unit 1 is L1, and the rotation of the second mass unit 11 is The distance (length) between the end portion 12 in the direction (longitudinal direction) substantially perpendicular to the movement center axis 41 is L2, and the direction substantially perpendicular to the rotation center axis 41 of the first mass unit 2 When the distance (length) between the first mass portion 13 and the second mass portion L3 is L3, the second mass portions 1 and 11 are provided independently of each other. The first mass part 2 does not interfere with each other, and L1 and L2 can be reduced regardless of the size of the first mass part 2. Thereby, the rotation angle of the second mass parts 1 and 11 (the deflection angle of the first mass part 2 with respect to the direction parallel to the surface on which the vibrating body 7 of the counter substrate 6 is provided) can be increased. The rotation angle of the first mass unit 2 can be increased.
Here, it is preferable that the dimensions of the second mass parts 1 and 11 and the first mass part 2 are set so as to satisfy the relationship of L1 <L3 and L2 <L3, respectively.

By satisfying the relationship, L1 and L2 can be further reduced, the rotation angle of the second mass parts 1 and 11 can be further increased, and the rotation angle of the first mass part 2 is further increased. be able to.
In this case, the maximum rotation angle of the first mass unit 2 is not particularly limited, but is preferably configured to be, for example, 20 ° or more.

In addition, since the second mass parts 1 and 11 can be driven with a smaller driving force by reducing L1 and L2, the voltage applied to each vibrating body 7 can be further reduced.
As described above, in this embodiment, L1 and L2 are set to be approximately equal, but it goes without saying that L1 and L2 may be different.

The average thickness of the first mass part 2 is preferably about 1 to 1500 μm, and more preferably about 10 to 300 μm.
In addition, the average thickness of the second mass parts 1 and 11 is preferably about 1 to 1500 μm, and more preferably about 10 to 300 μm.
The spring constant k ₁ of the first elastic connecting portion 5 is preferably about 1 × 10 ⁻⁴ to 1 × 10 ⁴ Nm / rad, and is preferably about 1 × 10 ⁻² to 1 × 10 ³ Nm / rad. More preferably, it is about 1 * 10 < ^-1 > ^-1 * 10 < ² > Nm / rad. Thereby, the deflection angle of the 1st mass part 2 can be enlarged more, suppressing the deflection angle of the 2nd mass parts 1 and 11. FIG.

Further, the spring constant k ₂ of the second elastic connecting portion 4 is preferably about 1 × 10 ⁻⁴ to 1 × 10 ⁴ Nm / rad, and about 1 × 10 ⁻² to 1 × 10 ³ Nm / rad. It is more preferable that it is about 1 × 10 ⁻¹ to 1 × 10 ² Nm / rad. Thereby, the rotation angle (swing angle) of the first mass unit 2 can be further increased.
When the spring constant of the first elastic connecting portion 5 is k ₁ and the spring constant of the second elastic connecting portion 4 is k ₂ , k ₁ and k ₂ satisfy the relationship k ₂ > k ₁ . Is preferred. Thereby, the rotation angle (swing angle) of the first mass unit 2 can be further increased while suppressing the deflection angle of the second mass units 1 and 11.

Further, when the inertia moment of the first mass part 2 is J ₁ and the inertia moment of the second mass part 1 (second mass part 11) is J ₂ , J ₁ and J ₂ are J it is preferable to satisfy _one of ≧ _{J 2 relations,} it is more preferable to satisfy the relationship of J 1> _{J 2.} Thereby, the rotation angle (swing angle) of the first mass unit 2 can be further increased while suppressing the deflection angle of the second mass units 1 and 11.

By the way, the natural frequency ω ₁ of the first vibration system is expressed as ω ₁ = (k when the moment of inertia of the first mass portion 2 is J ₁ and the spring constant of the first elastic connecting portion 5 is k _{1. 1} / J ₁ ) ^1/2 , and the natural frequency ω ₂ of the second vibration system is the inertia moment of the second mass part 1 as J ₂ and the spring constant of the second elastic coupling part 4 as k. ₂ is given by ω ₂ = (k ₂ / J ₂ ) ^1/2 .
It is preferable that the natural frequency ω ₁ of the first vibration system and the natural frequency ω ₂ of the second vibration system obtained as described above satisfy the relationship of ω ₂ > ω ₁ . Thereby, the rotation angle (swing angle) of the first mass unit 2 can be further increased while suppressing the deflection angle of the second mass units 1 and 11.

  As described above, according to the actuator 100, the vibrating body 7 is bent and displaced, so that the second mass portions 1 and 11 can be easily and reliably moved with a large driving force and a large rotation angle (a deflection angle). Can be driven. Further, since the first mass unit 2 is configured to rotate as the second mass units 1 and 11 are driven, an actuator having a large rotation angle (runout angle) of the second mass unit is provided. can do. Further, the second mass unit can be driven at a high frequency (for example, about 10 kHz).

Further, since the vibrating body 7 has a bimorph structure, for example, the dimension in the thickness direction (vertical direction in FIG. 2) of the actuator 100 can be made smaller than when the vibrating body has a laminated structure. it can.
Further, since the structure can be simplified as compared with an electrostatic drive type actuator, high integration, high density, and low cost can be achieved.

In addition, since the second mass unit 1 and the vibrating body 7 are coupled via the protrusion 51, the contact area between the vibrating body and the second mass unit can be reduced, and the loss of vibration can be reduced. it can. Moreover, since the 2nd mass parts 1 and 11 can be driven with a desired frequency easily and reliably, for example, control of the 1st mass part 2 can be performed easily.
For example, when the actuator of the present invention is used in a laser printer or the like, it is possible to perform high-quality printing and high-speed printing with higher resolution than when a polygon mirror or the like is used.

In the present embodiment, a vibrating body having a bimorph structure including the piezoelectric elements 53 and 55 is used as the vibrating body 7. However, the present invention is not particularly limited as long as the vibrating body includes a piezoelectric element.
Further, in the present embodiment, the vibrating bodies 7 and 7 and the second mass parts 1 and 11 are combined in advance, but may not be combined.

  In the present embodiment, the protrusions 51 and 51 are formed on the second mass parts 1 and 11. However, the protrusions 51 and 51 are not limited thereto, and may be formed on the vibrating body 7. It may be formed on both the vibrating bodies 7 and 7. In this case, for example, a method of forming a metal pattern such as gold on the surface of the vibrating body 7 and forming the protrusion 51 on the metal pattern by, for example, a plating method or the like can be given.

Further, the displacement detection means is not limited to the piezoresistive element 42 described above, and for example, a photo sensor or the like may be used. In this case, it is preferable to separately install a substrate or the like below the counter substrate 6 and to install a photosensor at a portion corresponding to the end of the first mass portion 2 on the surface of the substrate on the counter substrate 6 side.
The photosensor includes a light emitting unit that emits light toward the first mass unit 2 and a light receiving unit that receives light (reflected light) emitted from the light emitting unit and reflected by the first mass unit 2 and performs photoelectric conversion. When the light reflected by the second mass unit 1 is received by the light receiving unit, a voltage (current) having a magnitude corresponding to the amount of received light is output by photoelectric conversion.

Based on the voltage value (detected value), the control unit instructs the drive circuit described above to control the attitude (displacement) and the rotation frequency of the first mass unit 2.
Examples of the light emitting unit include a light emitting diode and a laser diode, and examples of the light receiving unit include a photodiode and a phototransistor.
In addition, when a laser diode is used, a phenomenon (Doppler effect) is used in which the frequency of reflected light that is reflected back when the laser beam is applied to the moving body changes in proportion to the speed of the moving body. The rotation angle of the first mass unit 2 can also be detected using a laser Doppler method, which is a method for measuring the speed of the moving body.

Next, an example of the manufacturing method of the actuator 100 as shown in FIGS. 1-5 is demonstrated, referring an accompanying drawing.
6 and 7 are process diagrams (partial sectional views) showing an example of a method for manufacturing an actuator.
In the present embodiment, as an example, the case where the actuator 100 is manufactured by the following first to seventh steps will be described.

[First step] (Etching step)
First, the glass substrate 60 is prepared.
And as shown to Fig.6 (a), it corresponds to the part except the area | region which forms the recessed parts 62 and 62 and the recessed parts 71 and 71 on the upper surface of the glass substrate 60, for example, chromium, gold | metal | money, aluminum etc. Thus, a metal mask 63 is formed.

Next, after etching the upper surface side of the glass substrate 60 through the metal mask 63, the metal mask 63 is removed. Thereby, as shown in FIG.6 (b), the glass substrate 60 in which the recessed parts 62 and 62 and the recessed parts 71 and 71 were formed is obtained.
As an etching method, for example, one or more of physical etching methods such as plasma etching, reactive ion etching, beam etching, and light-assisted etching, and chemical etching methods such as wet etching are used in combination. be able to. Note that the same method can be used for etching in the following steps.

[Second step] (Sandblasting step)
Next, a through hole is formed in a portion corresponding to the first mass portion 2 of the glass substrate 60 by, for example, a method such as sand blasting. Thereby, as shown in FIG.6 (c), the opening part 61 is formed.
[Third Step] (Vibrating Body Joining Step)
Next, the end portions 17 and 17 of the vibrating bodies 7 and 7 are joined to the concave portions 71 and 71 by, for example, an adhesive. In addition, the adhesive used at the time of joining has a thing which does not have elasticity after hardening, for example, a cyanoacrylate adhesive, an epoxy adhesive, etc. are mentioned. Thereby, it can prevent suitably that the vibration of the vibrating body 7 is absorbed by the adhesive.
Through the above steps, as shown in FIG. 6D, the counter substrate 6 in which the recesses 62 and 62, the recesses 71 and 71, and the opening 61 are formed and the vibrators 7 and 7 are installed is obtained.
Next, as shown in FIG. 7E, a silicon substrate 105 is prepared, and the fourth and subsequent steps are performed.

[Fourth step] (Silicon processing step 1)
First, as shown in FIG. 7 (f), the piezoresistive element 42 is installed at a site corresponding to the first elastic coupling portion 5 on the upper surface side of the silicon substrate 105.
[Fifth step] (silicon processing step 2)
Next, a photoresist is applied to the lower surface of the silicon substrate 105, and exposure and development are performed. Thereby, a resist mask (not shown) is formed so as to correspond to the shape of the protrusions 51, 51.

Next, after etching the silicon substrate 105 through this resist mask, the resist mask is removed. As a result, as shown in FIG. 7G, protrusions 51 are formed on the lower surface of the silicon substrate 105.
Further, the protrusions 51 may be formed by polishing the lower surface of the silicon substrate 105.

[Sixth step] (Silicon processing step 3)
Next, a photoresist is applied to the lower surface of the silicon substrate 105, and exposure and development are performed. Thereby, so as to correspond to the shapes of the second mass parts 1, 11, the first mass part 2, the support part 3, the second elastic coupling parts 4, 4, the first elastic coupling parts 5, 5, A resist mask (not shown) is formed.

Next, after etching the silicon substrate 105 through this resist mask, the resist mask is removed. Accordingly, as shown in FIG. 7 (h), the second mass portions 1 and 11, the first mass portion 2, the support portion 3, the second elastic coupling portions 4 and 4, and the first elastic coupling portion 5 are used. 5 are formed.
Next, the light reflecting portion 21 is formed on the first mass portion 2 by, for example, a vacuum deposition method or the like.
Through the above steps, as shown in FIG. 7 (i), the second mass portions 1, 11, the first mass portion 2, the support portion 3, the second elastic connection portions 4, 4, the first elastic connection The structure 140 in which the portions 5 and 5 and the light reflecting portion 21 are formed is obtained.

[Seventh step] (joining step)
Next, the counter substrate 6 obtained in the first to third steps and the structure 140 obtained in the fourth to sixth steps are bonded by, for example, an adhesive, anodic bonding, alloy bonding, or the like. In addition, as an adhesive agent at the time of using an adhesive agent, what does not have elasticity after hardening is preferable, for example, a cyanoacrylate adhesive agent, an epoxy adhesive agent, etc. are mentioned.

The actuator 100 of 1st Embodiment as shown in FIGS. 1-5 is obtained by the above.
The fourth to sixth steps may be performed simultaneously with the first to third steps, or may be performed prior to the first to third steps.
Next, a second embodiment of the actuator of the present invention will be described.
FIG. 8 is a plan view showing a second embodiment of the actuator of the present invention.

Hereinafter, the actuator 1 of the second embodiment will be described with a focus on the differences from the first embodiment described above, and description of similar matters will be omitted.
The actuator 1 of the second embodiment differs from the first embodiment in the arrangement of the vibrating body 7 and the position of the protrusion 51.
As shown in FIGS. 8 and 9, in the actuator 1 of the second embodiment, the end portions 17 and 17 of the vibrating bodies 7 and 7 are installed (fixed) on the upper surface of the support portion 3. Further, the end portions 18 and 18 of the vibrating bodies 7 and 7 are positioned above the end portions 14 and 14 in the longitudinal direction of the second mass portions 1 and 11, respectively. Further, the end portions 18 and 18 are fixed to the upper surfaces of the second mass portions 1 and 11 via the protrusions 51 and 51, respectively. That is, the end portions 14 and 14 of the second mass portions 1 and 11 and the end portions 18 and 18 of the vibrating bodies 7 and 7 are installed so as to overlap each other in plan view.

In addition, the portion where the end portions 17 of the support portion 3 of the present embodiment are installed is thicker than the other portions of the support portion 3 by approximately the same thickness as the thickness of the protrusion 51 in the vertical direction in FIG. A thick portion 30 is formed.
Next, an example of a method for manufacturing the actuator 100 as shown in FIGS. 8 and 9 will be described with reference to the accompanying drawings.
10 and 11 are process diagrams (partial sectional views) showing an example of a method for manufacturing an actuator.
Hereinafter, the manufacturing method of the actuator according to the second embodiment will be described. However, differences from the first embodiment will be mainly described, and description of similar matters will be omitted.

[First step] (Etching step)
First, the glass substrate 60 is prepared.
Then, as shown in FIG. 10A, a metal mask 63 is formed on the upper surface of the glass substrate 60 by using, for example, chromium, gold, aluminum, or the like so as to correspond to a portion excluding the region where the recesses 62 and 62 are formed. Form.
Next, after etching the upper surface of the glass substrate 60 through the metal mask 63, the metal mask 63 is removed. Thereby, as shown in FIG.10 (b), the glass substrate 60 in which the recessed parts 62 and 62 were formed is obtained.

[Second step] (Sandblasting step)
Next, a through hole is formed in a portion corresponding to the first mass portion 2 of the glass substrate 60 by, for example, a method such as sand blasting. Thereby, as shown in FIG.10 (c), the opening part 61 is formed.
The counter substrate 6 in which the concave portions 62 and 62 and the opening 61 are formed is obtained by the above process.

[Third Step] (Silicon Processing Step 1)
First, as shown in FIG. 11D, a silicon substrate 105 is prepared.
Next, a resist mask (not shown) is formed on the upper surface of the silicon substrate 105 so as to correspond to the shape of the protrusions 51 and 51 and the shape of the thick portions 30 and 30 of the support portion 3.
Next, after etching the silicon substrate 105 through this resist mask, the resist mask is removed. As a result, as shown in FIG. 11E, the protrusions 51 and 51 and the thick portions 30 and 30 are formed on the upper surface of the silicon substrate 105.
Further, the protrusions 51 and 51 and the thick portions 30 and 30 may be formed by polishing the upper surface of the silicon substrate 105.

[Fourth Step] (Silicon Processing Step 2)
A process similar to the fourth process of the first embodiment is performed (see FIG. 11F).
[Fifth step] (silicon processing step 3)
A process similar to the sixth process of the first embodiment is performed (see FIG. 11G).
[Sixth step] (joining step)
A process similar to the seventh process of the first embodiment is performed (see FIG. 11H).

The actuator 100 of 2nd Embodiment as shown in FIG. 8, FIG. 9 is obtained by the above.
According to this actuator 1, the same effect as the actuator 1 of the first embodiment described above can be obtained.
In this actuator 1, the thickness of the support portion 3 (the thickness in the vertical direction in FIG. 9) is set to the rotation angle (runout angle) when the second mass portions 1, 11 and the first mass portion 2 are used. In the case where the thickness of the counter substrate 6 is sufficiently thick so as not to be restricted, the counter substrate 6 can be made unnecessary, and thus the structure can be further simplified.

Next, a third embodiment of the actuator of the present invention will be described.
FIG. 12 is a plan view showing a third embodiment of the actuator of the present invention.
Hereinafter, the actuator 100 shown in FIG. 12 will be described with a focus on differences from the second embodiment, and description of similar matters will be omitted.
The actuator 100 of the present embodiment has a structure 110 as shown in FIG.

The structural body 110 includes a U-shaped connecting member 70 and the vibrating body 7 in plan view.
The connecting member 70 includes a plate-like base portion 72 and plate-like support portions 73 and 73, and the vibrating body 7 is fixed to a substantially central portion of the base portion 72. Further, the end portions 19 and 19 of the support portions 73 and 73 are fixed to the second mass portions 1 and 11 via the protrusions 51 and 51, respectively.

  When using the actuator 100 of the present embodiment, an AC voltage is applied between the third electrode 54 and the group electrode 57 of the vibrating body 7. As a result, an alternating voltage is applied to the first piezoelectric element 53 and the second piezoelectric element 55, the first piezoelectric element 53 contracts, and the second piezoelectric element 55 expands, so that the vibrating body 7 is illustrated. 2 When the base part 72 of the connecting member 70 is bent and displaced upward in the middle, a substantially equal driving force is transmitted to the second mass parts 1 and 11 via the connecting member 70. By this driving force, the second mass parts 1 and 11 rotate by a predetermined angle around the rotation center axis 41 (second elastic coupling part 4). As the second mass parts 1 and 11 rotate, the first mass part 2 connected via the first elastic connection part 5 is connected to the rotation center shaft 41 (first elastic connection part 5). ) Around a predetermined angle.

According to this actuator 100, the same effect as the actuator 100 of the second embodiment described above can be obtained.
In this actuator 100, the driving force of the vibrating body 7 acts on the second mass parts 1 and 11 substantially equally, and the second mass parts 1 and 11 can be driven synchronously easily and reliably. Thereby, control of the 2nd mass part can be made simple. Further, the cost and weight can be reduced by reducing the number of vibrating bodies 7.

The actuator 100 of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part is replaced with an arbitrary configuration having the same function. be able to. In addition, any other component may be added to the present invention.
Further, the present invention may be a combination of any two or more configurations (features) (processes) of the above-described embodiments.

Moreover, in embodiment mentioned above, although demonstrated as what has 1 pair of 2nd elastic connection parts 4, it is not limited to this, For example, 2 pairs or more may be sufficient.
Moreover, in embodiment mentioned above, although demonstrated as what has 1 pair of 1st elastic connection parts 5, it is not limited to this, For example, 2 pairs or more may be sufficient.
In the above-described embodiment, the configuration in which the light reflecting portion 21 is provided on the side of the first mass portion 2 opposite to the side on which the counter substrate 6 is provided has been described. The structure provided in this surface may be sufficient, and the structure provided in both surfaces may be sufficient.

Further, in the first embodiment and the second embodiment described above, the vibrators 7 and 7 are provided at positions corresponding to the second mass unit 1 and positions corresponding to the second mass unit 11, respectively. However, the present invention is not limited to this. For example, the vibrating body 7 may be provided only at one end of the second mass unit 1 and the second mass unit 11. Good.
In each of the above-described embodiments, the shapes of the first elastic coupling portion and the second elastic coupling portion have been described with respect to the illustrated configuration. However, the shape is not limited to this, and for example, the shape is a crank shape or the like. It may be.

An insulating film for preventing a short circuit may be provided on the surface of the surface of the second mass parts 1 and 11 facing the vibrating body 7.
The actuator described above is suitable for driving MEMS (Micro Electro-Mechanical Systems) devices such as laser printers, barcode readers, optical scanners such as scanning confocal laser microscopes, tunable etalon, and imaging displays. Can be applied to.

It is a top view which shows 1st Embodiment of the actuator of this invention. It is sectional drawing in the AA line in FIG. It is a top view which shows the counter substrate of 1st Embodiment. It is sectional drawing in the BB line in FIG. It is a side view of a vibrating body (bimorph type piezoelectric element). It is process drawing (partial sectional drawing) which shows an example of the manufacturing method of an actuator. It is process drawing (partial sectional drawing) which shows an example of the manufacturing method of an actuator. It is a top view which shows 2nd Embodiment of the actuator of this invention. It is sectional drawing in the CC line | wire in FIG. It is process drawing (partial sectional drawing) which shows an example of the manufacturing method of an actuator. It is process drawing (partial sectional drawing) which shows an example of the manufacturing method of an actuator. It is a top view which shows 3rd Embodiment of the actuator of this invention. It is a figure for demonstrating the conventional actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Actuator 1, 11 ... 2nd mass part 12, 13, 14 ... End part 17 ... End part 18 ... End part 2 ... 1st mass part 21 ... Light reflection part 3 ... Support portion 4 …… Second elastic connecting portion 41 …… Rotation center axis 42 …… Piezoresistive element 5 …… Second elastic connecting portion 51 …… Protrusion 52 …… First electrode 53 …… First Piezoelectric element 54 ... third electrode 55 ... second piezoelectric element 56 ... second electrode 57 ... group electrode 6 ... counter substrate 61 ... opening 62 ... recess 63 ... metal mask 7 ... ... Vibrating body (bimorph type piezoelectric element) 70 ... connecting member 71 ... concave 72 ... base part 73 ... support part 60 ... glass substrate 105 ... silicon substrate 110 ... structure 140 ... structure 200 ... ... Spacer 300 ... Movable electrode plate 300a ... Both ends fixed part 3 0b ...... torsion bar 300c ...... movable electrode portion 400 ...... fixed electrode 500 ...... power 600 ...... switch 1000 ...... glass substrate A, B ...... longitudinally C ...... direction L1, L2, L3 ...... distance

Claims (16)

A first mass part;
A second mass part;
A vibrating body that includes a piezoelectric element and is driven and vibrated by applying an AC voltage to the piezoelectric element;
A support part for supporting the first mass part and the second mass part;
At least one pair of first elastic members that connect the first mass unit and the second mass unit so that the first mass unit is rotatable with respect to the second mass unit. A connecting portion;
And at least one pair of second elastic coupling portions that couple the second mass portion and the support portion so that the second mass portion is rotatable with respect to the support portion. ,
The actuator, wherein the second mass unit is driven by the vibration of the vibrating body, and the first mass unit rotates accordingly. A first mass part;
A pair of second mass parts respectively provided on one end side and the other end side of the first mass part via the first mass part;
A support part for supporting the first mass part and the second mass parts;
A vibrating body that includes a piezoelectric element and is driven and vibrated by applying an AC voltage to the piezoelectric element;
At least one pair of first masses connecting the first mass parts and the second mass parts so that the first mass parts are rotatable with respect to the second mass parts. An elastic connecting portion of
At least one pair of second elastic connecting portions that connect each of the second mass portions and the support portion such that each of the second mass portions is rotatable with respect to the support portion; Have
Each of the second mass parts is driven by the vibration of the vibrating body, and the first mass part rotates accordingly. A plurality of the vibrators;
The actuator according to claim 2, wherein the vibrating bodies are respectively provided at portions corresponding to the pair of second mass parts.   4. The actuator according to claim 2, wherein the vibrating body is configured to be able to drive the pair of second mass parts synchronously. 5. The vibrating body has a bimorph structure,
The actuator according to any one of claims 1 to 4, wherein the vibrating body is configured to transmit a driving force to the second mass portion by bending displacement of the piezoelectric element. Each of the vibrating body and the second mass part has a long plate shape,
The actuator according to any one of claims 1 to 5, wherein one end portion of the vibrating body and one end portion of the second mass portion are provided so as to overlap in a plan view.   The actuator according to claim 6, wherein the other end portion of the vibrating body is fixed to the support portion. A counter substrate provided to face the support portion;
The actuator according to claim 6, wherein the other end of the vibrating body is fixed to the counter substrate. The counter substrate is provided with a recess,
The actuator according to claim 8, wherein the other end of the vibrating body is inserted and fixed into the recess. A protrusion is provided on one or both of the one end of the vibrating body and the one end of the second mass unit,
The actuator according to claim 6, wherein the vibrating body is configured to transmit a driving force to the second mass portion via the protrusion.   The actuator according to any one of claims 1 to 10, wherein the second mass unit and the vibrating body are coupled in advance.   The actuator according to any one of claims 1 to 11, further comprising a displacement measuring unit that measures a displacement of the first mass unit or the second mass unit when the vibrating body vibrates.   The actuator according to claim 12, wherein the displacement measuring means includes a piezoresistive element provided in at least one of the pair of first elastic coupling portions and the pair of second elastic coupling portions.   The actuator according to claim 13, wherein the displacement measuring unit is capable of detecting the displacement in a non-contact manner with respect to the first mass portion and the second mass portion.   The structure according to any one of claims 12 to 14, wherein the rotation angle of the first mass portion with respect to the first elastic coupling portion is controlled based on detection of the displacement measuring means. Actuator. 16. The vibration of the vibrating body is controlled so that the frequency of the AC voltage is equal to a resonance frequency of a two-degree-of-freedom vibration system in which the second mass unit and the first mass unit resonate. Actuator.

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