JP2006075944A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator capable of obtaining driving with large driving force and at high frequency and having a large swing angle (amplitude). <P>SOLUTION: The actuator has a first mass part 2; second mass parts 1, 11; vibrators 7, 7, 7, 7 provided in the respective corresponding positions of both ends of the second mass parts 1, 11; a support part 3 for supporting the first mass part 2 and the second mass parts 1, 11; first elastic connection parts 5, 5 for connecting the first mass part 2 and the second mass parts 1, 11 so that the first mass part 2 is turnable relative to the second mass parts 1, 11; and second elastic connection parts 4, 4 for connecting the second mass parts 1, 11 and the support part 3 so that the second mass part 1 is turnable relative to the support part 3. The second mass parts 1, 11 are driven by vibration in the thickness direction of a piezoelectric element by the piezoelectric longitudinal effect of each vibrator 7, and in association with it, the first mass part 2 is turned. <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 torsional vibrator with one degree of freedom in which electrodes are arranged in a parallel plate shape as shown in FIG. 12 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. 12 fixes both end 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 a high frequency 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 pair of layers provided at positions corresponding to both ends of the second mass part, each having a laminated structure in which piezoelectric elements are laminated, and driven and vibrated by applying an alternating voltage to each piezoelectric element. Vibration body of
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 second mass unit is driven by the vibration in the thickness direction of the piezoelectric element due to the piezoelectric longitudinal effect of the vibrating body, and the first mass unit is rotated 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 both sides 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 pair of vibrating bodies having a laminated structure in which piezoelectric elements are laminated, and being driven and vibrated by applying an alternating voltage to the piezoelectric elements;
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
One pair of vibrating bodies of the two pairs of vibrating bodies is provided at positions corresponding to both ends of one second mass section of the pair of second mass sections, respectively. And
The other pair of vibrating bodies of the two pairs of vibrating bodies is provided at positions corresponding to both ends of the other second mass section of the pair of second mass sections. And
Each of the second mass parts is driven by the vibration in the thickness direction of the piezoelectric element due to the piezoelectric longitudinal effect of the vibrator, and the first mass part is rotated 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 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 according to the aspect of the invention, it is preferable that the two pairs of vibrating bodies are configured to be able to drive the pair of second mass parts in a synchronous manner.
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 each of the pair of vibrating bodies is provided in substantially line symmetry with respect to a central axis around which the second mass unit rotates in a plan view.
Thereby, control of a pair of 2nd mass parts can be simplified.

In the actuator of the present invention, the phase difference between the AC voltage applied to the piezoelectric element of one vibrating body of the pair of vibrating bodies and the AC voltage applied to the piezoelectric element of the other vibrating body is It is preferably 180 °.
Thereby, a 2nd mass part can be driven reliably.
The actuator of the present invention includes a counter substrate provided to face the second mass part with a gap therebetween,
It is preferable that the pair of vibrators are respectively fixed to portions corresponding to the second mass portions of the counter substrate.
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, the counter substrate is provided with a recess,
It is preferable that the pair of vibrators are respectively inserted and fixed in the recesses.
Thereby, the second mass unit can be driven with a large driving force with a simple configuration.
In the actuator of the present invention, a reinforcing plate is provided between the support portion and the counter substrate.
It is preferable that the support portion and the counter substrate are joined to each other via the reinforcing plate.
Thereby, the intensity | strength of a support part can be reinforced easily and reliably with a simple structure.

In the actuator of the present invention, a protrusion is provided on one or both of the pair of vibrating bodies and the second mass unit,
Preferably, each of the pair of vibrating bodies is configured to transmit a driving force to the second mass unit via the protrusion.
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.

In the actuator of the present invention, the position of the most displaced portion of the second mass portion when the second mass portion is most rotated in one direction by the vibration of the pair of vibrating bodies, From the distance from the position of the most displaced part of the second mass part when the second mass part is most rotated in the direction opposite to the one direction by the vibration of the pair of vibrating bodies, It is preferable to increase the length.
Thereby, contact other than the projection of the second mass part and the vibrating body can be reliably prevented.

In the actuator according to the aspect of the invention, it is preferable that the most displaced portion of the second mass portion is an end portion in a direction substantially perpendicular to a central axis around which the second mass portion rotates.
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. .
As a result, the rotation angle of the second mass part can be detected easily and reliably, 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 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.
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 cross-sectional view taken along line BB in FIG. 4 is a side view of the vibrating body (multilayer piezoelectric element), FIG. 5 is a view showing an example of an AC voltage applied to the vibrating body, and FIG. 6 is a view showing the rotation of the second mass unit. It is. FIG. 6 is an exaggerated view of the rotation of the second mass unit and does not reflect the actual rotation. FIG. 6 is a diagram schematically showing the protrusions, and does not reflect actual dimensions. That is, the size (length) of the protrusion 51 and the like with respect to the second mass portion 1 is shown to be larger than the actual size.

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, a support part 3, a reinforcing plate 9, and a counter substrate 6. And two pairs of vibrating bodies 7.

  The actuator 100 has the first mass part 2 at the center, the second mass part 1 is provided on the right side, and the second mass part 11 is provided on the left side via the first mass part 2. Yes. That is, the second mass parts 1 and 11 are provided on both sides of the first mass part 2, respectively. Support parts 3 are arranged on the right side of the second mass part 1 in the drawing and on the left side of the second mass part 11 in the drawing, 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.

As shown in FIG. 2, the reinforcing plate 9 is installed between the support portion 3 and the counter substrate 6, and the support portion 3 and the counter substrate 6 are joined to each other via the reinforcing plate 9. As a result, the second mass parts 1 and 11 face the counter substrate 6 with a gap therebetween.
As shown in FIG. 2, the counter substrate 6 has an opening 61 at a position corresponding to the first mass unit 2.

  In addition, as shown in FIG. 3, a pair of concave portions 62 is formed on the upper surface of the counter substrate 6 at a portion corresponding to the second mass portion 1 and is substantially symmetric (line symmetric) in plan view about the rotation center axis 41. In addition, a pair of recesses 62 are formed in a portion corresponding to the second mass portion 11 so as to be substantially line symmetric about the rotation center axis 41. That is, a total of two pairs of recesses 62 are formed. In addition, each vibrator 7 is inserted and fixed in each recess 62.

A pair of vibrating bodies 7 on the right side in FIG. 1 are respectively installed below the both ends of the second mass unit 1 so as to be substantially symmetric (line symmetric) in plan view about the rotation center axis 41. Yes. In addition, the pair of vibrating bodies 7 on the left side in FIG. 1 are installed so as to be substantially line symmetric about the rotation center axis 41 at the lower part of both ends of the second mass part 11.
Four projections 51, 51, 51, 51 as vibration transmission bodies are formed on the second mass parts 1, 11. The protrusion 51 may not be provided.

Since each vibration body 7 has the same configuration and function, a single vibration body 7 will be typically described below.
As shown in FIG. 4, the vibrating body 7 includes piezoelectric elements 71 to 76 as electric / mechanical conversion elements.
Each of the piezoelectric elements 71 to 76 has a substantially rectangular plate shape, and is alternately stacked so that the polarization directions in the thickness direction (arrows A and B in FIG. 4) are reversed, for example, an adhesive or the like. It is fixed by.

Plating layers made of gold plating or the like are formed between the piezoelectric elements 71 to 76, the upper surface of the piezoelectric element 71, and the lower surface of the piezoelectric element 76, and the electrodes 77 and 78 for applying voltage are formed by these plating layers. Is formed. These piezoelectric elements 71 to 76 and the electrodes 77 and 78 constitute a vibrating body 7 having a laminated structure.
The electrode 77 between the piezoelectric elements 71 and 72, the electrode 77 between the piezoelectric elements 73 and 74, and the electrode 77 between the piezoelectric elements 75 and 76 are electrically connected to each other by, for example, the external electrode 53. Is configured.

  Further, the electrode 78 on the upper surface of the piezoelectric element 71, the electrode 78 between the piezoelectric elements 72 and 73, the electrode 78 between the piezoelectric elements 74 and 75, and the electrode 78 on the lower surface of the piezoelectric element 76 are electrically connected to each other by the external electrode 52, for example. Are connected to each other to form a group electrode 57. The group electrode 56 and the group electrode 57 are connected to a drive circuit described later. Thereby, the direction of polarization of the piezoelectric elements 71 to 76 is the same as the direction of the applied voltage.

Here, when an AC voltage from the drive circuit is applied to the piezoelectric elements 71 to 76 via the group electrodes 56 and 57, the vibrating body 7 has a thickness of each piezoelectric element 71 to 76 due to the piezoelectric longitudinal effect. Due to the displacement in the direction (vertical direction in FIG. 4), it is displaced in the direction of arrow C in FIG.
When the actuator 100 described later is used, the second mass parts 1 and 11 are pressed and driven by the displacement of the vibrating body 7 due to the piezoelectric longitudinal effect.

The constituent materials of these piezoelectric elements 71 to 76 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 42.

  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 using the actuator 100 of the present embodiment, an AC voltage is applied between the group electrode 56 and the group electrode 57 of each vibrating body 7. More specifically, for example, the upper two vibrating bodies (one of the pair of vibrating bodies) 7 and 7 in FIG. 1 are respectively provided with sine waves (waveforms) as shown in FIG. 5A is applied to the lower two vibrating bodies (the other vibrating body of the pair of vibrating bodies) 7 and 7 in FIG. When a voltage of a sine wave (waveform) having a phase difference of 180 ° is applied to each of the piezoelectric elements 71 to 76 of each vibrating body 7, an alternating voltage is applied. First, in the section T1, the upper side in FIG. The two vibrating bodies 7 and 7 are displaced by the piezoelectric longitudinal effect and press the second mass parts 1 and 11 via the upper projections 51 and 51, respectively, and against the second mass parts 1 and 11. To transmit the driving force. 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 portions 1 and 11 rotate, the first mass portion 2 connected via the first elastic connection portion 5 is connected to the rotation center shaft 41 (the first elastic connection portion 5. ) Around a predetermined angle.

  Thereafter, in the section T2, the amplitude of the alternating voltage is changed, the displacement amount of each vibrating body 7 is changed, and the driving force to the second mass parts 1 and 11 is changed, and the two lower vibrations in FIG. The bodies 7 and 7 press the second mass parts 1 and 11 through the lower projections 51 and 51, and transmit a driving force to the second mass parts 1 and 11. With this driving force, the second mass parts 1 and 11 cause the rotation center shaft 41 (second elastic coupling part 4) to move in the opposite direction to the rotation direction of the second mass parts 1 and 11. Rotate a predetermined angle around the center. Along with the rotation of the second mass parts 1 and 11, the first mass part 2 connected via the first elastic connection part 5 is relative to the rotation direction of the first mass part 2. In the opposite direction, it rotates by a predetermined angle around the rotation center shaft 41 (first elastic connecting portion 5).

Thereafter, in the same manner, by applying an AC voltage to each vibrating body 7, the second mass parts 1 and 11 vibrate (rotate) about the rotation center shaft 41 (second elastic connecting part 4).
Along with the vibration 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 (the first elastic connecting portion 5). ) At 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 each of the group electrodes 56 and 57 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 each vibrating body 7 is equal to the resonance frequency of the two-degree-of-freedom vibration system in which the second mass units 1, 11 and the first mass unit 2 resonate. It is preferable to set. 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.

  By the way, the actuator 100 is most displaced when the second mass parts 1 and 11 are most rotated in the clockwise direction in FIG. 6 by the vibrations of the vibrating bodies 7 (two pairs of vibrating bodies 7). The second mass portions 1 and 11 are most rotated in the counterclockwise direction in FIG. 3 by the position S1 of the S point of the end portion 12 in FIG. The length of each projection 51 (length in the vertical direction in FIG. 6) L5 is made longer than the distance L4 from the position S2 of the S point of the end portion 12 in FIG. Is preferred. As a result, for example, when substantially all of the vibrating bodies 7 are disposed below the second mass parts 1 and 11, respectively, or when the vibrating bodies 7 overlap the rotation center axis 41 in plan view. Even in a case where the second mass portions 1 and 11 and the vibrating bodies 7 are not disposed at positions other than the protrusions 51, the contact can be reliably prevented.

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 this actuator 100, each vibrating body 7 vibrates due to the piezoelectric longitudinal effect, so that the second mass portions 1 and 11 can be easily and surely driven with a large driving force and a large rotation. It can be driven at an angle (a deflection angle). 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).

  In addition, since each vibrating body 7 has a laminated structure, for example, the thickness direction of the actuator 100 (vertical direction in FIG. 2) is larger than when each vibrating body 7 has a bimorph structure. Features such as large driving force and fast response speed. For this reason, each vibrating body 7 drives the second mass units 1 and 11 with a larger deflection angle by pressing the vicinity of the rotation center axis 41 of the second mass units 1 and 11, respectively. can do.

Further, since one pair of vibrating bodies 7 is provided for each of the second mass parts 1, 11, one vibrating body 7 is provided for each of the second mass parts 1, 11. Compared with the case where it exists, the driving force with respect to each of the 2nd mass parts 1 and 11 can be substantially doubled.
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 each vibrating body 7 is configured to transmit a driving force to the second mass parts 1 and 11 via each protrusion 51, each vibrating body 7 and the second mass parts 1 and 11 The contact area is reduced, and vibration loss can be reduced. 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.

  When the actuator of the present invention is used in, for example, a laser printer or the like, it is possible to perform high-quality printing and high-quality printing at a higher resolution than when a polygon mirror or the like is used.

  In the present embodiment, each protrusion 51 is formed on the second mass parts 1 and 11, but is not limited thereto, and may be formed on each vibrating body 7, or the second mass parts 1 and 11. And each vibrating body 7 may be formed. In this case, for example, there is a method in which a metal pattern such as gold is formed on the surface of each vibrating body 7 and each protrusion 51 is formed on the metal pattern by, for example, a plating method.

Further, the displacement measuring 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 first mass unit 2 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 a method for manufacturing the actuator 100 as shown in FIGS. 1 to 3 will be described with reference to the accompanying drawings.
7 to 9 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 sixth steps will be described.

[First step] (Etching step)
First, the substrate 60 is prepared.
The constituent material of the substrate 60 is not particularly limited as long as it has high rigidity, and examples thereof include glass such as SUS (Steel Use Stainless) and Pyrex glass ("Pyrex" is a registered trademark).

Then, as shown in FIG. 7A, for example, chromium, gold, aluminum, or the like is formed on the upper surface of the substrate 60 so as to correspond to a portion excluding a region where the four concave portions 62, 62, 62, 62 are formed. Thus, a metal mask 63 is formed.
Next, after etching the upper surface side of the substrate 60 through the metal mask 63, the metal mask 63 is removed. Thereby, as shown in FIG.7 (b), the board | substrate 60 in which each recessed part 62 was 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.

At this time, the second mass parts 1, 11 are appropriately adjusted by appropriately adjusting the position and depth at which each recess 62 is formed according to the shape of the second mass parts 1, 11, the thickness of each vibrating body 7, and the like. And the relationship between the vibrating bodies 7 can be made favorable.
Further, by adjusting the thickness of the substrate 90 to be described later, the height relationship between the second mass parts 1 and 11 and each vibrating body 7 can be adjusted, and each concave part 62 is not formed. If the height relationship is appropriate, the above-described process may not be performed.
Next, a groove (not shown) or the like for guiding a conducting wire for applying an AC voltage to each vibrating body 7 is formed.

[Second step] (Sandblasting step)
Next, a through hole is formed in a portion corresponding to the first mass portion 2 of the substrate 60 by a method such as sandblasting. Thereby, as shown in FIG.7 (c), the opening part 61 is formed.
[Third Step] (Vibrating Body Joining Step)
Next, each vibrating body 7 is joined to each recessed part 62 with an adhesive etc., for example. 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 each vibrating body 7 is absorbed by the adhesive.
Through the above steps, as shown in FIG. 7D, the counter substrate 6 in which the opening 61 and the concave portions 62 are formed and the vibrators 7 are installed is obtained.

[Fourth step] (Silicon processing step 1)
On the other hand, a silicon substrate 105 is prepared as shown in FIG.
Next, as shown in FIG. 8F, the piezoresistive element 42 is installed at a portion corresponding to the first elastic coupling portion 5 on the upper surface side of the silicon substrate 105.
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, 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. 8G, each protrusion 51 is formed on the lower surface of the silicon substrate 105.
Further, each protrusion 51 may be formed by polishing the lower surface of the silicon substrate 105.

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. Thereby, as shown in FIG. 8 (h), the second mass parts 1, 11, the first mass part 2, the support part 3, the second elastic connection parts 4, 4, and the first elastic connection part 5 are provided. 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. 8 (i), the second mass portions 1, 11, the first mass portion 2, the support portion 3, the second elastic coupling portions 4, 4, and the first elastic coupling. The structure 140 in which the portions 5 and 5 and the light reflecting portion 21 are formed is obtained.

[Fifth step] (Jointing step 1)
First, as shown in FIG. 9J, a substrate 90 is prepared.
Next, as shown in FIG. 9K, the reinforcing plate 9 is formed on the substrate 90 by, for example, etching.
The constituent material of the substrate 90 is not particularly limited as long as it increases the rigidity of the structure 140 by bonding to the structure 140 described below. For example, glass such as Pyrex glass ("Pyrex" is a registered trademark) is used. Etc.

Next, as shown in FIG. 9L, the structure 140 and the reinforcing plate 9 are joined by, for example, an adhesive, anodic bonding, alloy bonding, or the like. Thereby, the structure 150 in which the reinforcing plate 9 and the structure 140 are joined is obtained.
In addition, when an adhesive is used, an adhesive that does not have elasticity after curing is preferable, and examples thereof include a cyanoacrylate adhesive and an epoxy adhesive (the same applies to the adhesive in the sixth step).

[Sixth Step] (Jointing Step 2)
Next, the counter substrate 6 obtained in the first to third steps and the structure 150 obtained in the fourth to fifth steps are bonded by, for example, an adhesive, anodic bonding, alloy bonding, or the like. . Further, the counter substrate 6 and the structure 150 may be mechanically clamped.
The actuator 100 of 1st Embodiment as shown in FIGS. 1-3 is obtained by the above.

The fourth to fifth steps may be performed simultaneously with the first to third steps, or may be performed before the first to third steps.
Next, a second embodiment of the actuator of the present invention will be described.
FIG. 10 is a plan view showing a second embodiment of the actuator of the present invention, and FIG. 11 is a sectional view taken along the line CC in FIG.

Hereinafter, the actuator 100 shown in FIGS. 10 and 11 will be described with a focus on differences from the first embodiment, and description of similar matters will be omitted.
The actuator 100 of this embodiment has two structures 110 and 110 as shown in FIG.
Hereinafter, since the structures and functions of the structures 110 are the same except for the position of the vibrating body 7, the structure 110 on the lower side in FIG.

The structural body 110 includes the connecting member 30 and the vibrating body 7.
The connecting member 30 includes two plate-like base portions 31 and 31 and a support portion 32, and the base portions 31 and 31 are coupled to each other by the support portion 32.
The base 31 on the right side in FIG. 11 is fixed to the upper side in FIG. Thereby, the base parts 31 and 31 vibrate simultaneously by the vibration of the vibrating body 7.

On the other hand, in the structure 110 on the upper side in FIG. 10, the vibrating body 7 is installed in the lower part in FIG. 11 of the base part 31 on the left side of the structure 110. It is fixed.
When using the actuator 100 of the present embodiment, for example, a sine wave as shown in FIG. 5A is applied to the upper vibration body (one vibration body of a pair of vibration bodies) 7 in FIG. A voltage of (waveform) is applied, and the lower vibrating body (the other vibrating body of the pair of vibrating bodies) 7 in FIG. 10 is applied to FIG. 5 (a) as shown in FIG. 5 (b). When a sine wave (waveform) voltage having a phase difference of 180 ° is applied, first, in the section T1, the upper vibrating body 7 in FIG. 10 is displaced and connected to the upper side in FIG. 11 due to the piezoelectric longitudinal effect. By pressing the base portions 31, 31 of the member 30, substantially equal driving force is transmitted to the second mass portions 1, 11 via the upper projections 51, 51 in FIG. 10.

  Thereafter, in the section T2, the amplitude of the AC voltage is changed, the displacement amount of each vibrating body 7 is changed, and the driving force to the second mass parts 1 and 11 is changed, and the two lower vibrations in FIG. The body 7 is displaced upward in FIG. 11 due to the piezoelectric longitudinal effect and presses the base portions 31 and 31 of the connecting member 30, whereby the second mass portion 1 is interposed via the lower protrusions 51 and 51 in FIG. 10. , 11 is transmitted with substantially equal driving force.

According to this actuator 100, the same effect as the actuator 100 of the first 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.

  In the above-described embodiment, each pair of vibrating bodies 7 is installed so as to be substantially line-symmetric with respect to the rotation center axis 41, but is not limited to this. It may be installed so as to be substantially point-symmetric with respect to it. When the actuator 100 having such a structure is used, the phase of the voltage applied to each pair of vibrating bodies 7 may be the same, so that the drive circuit is simplified.

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.

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.
Moreover, 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 bodies 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 sectional drawing in the BB line in FIG. It is a side view of a vibrating body (multilayer piezoelectric element). It is a figure which shows an example of the alternating voltage applied to a vibrating body. It is a figure which shows rotation of a 2nd mass part. It is process drawing (sectional drawing) which shows an example of the manufacturing method of an actuator. It is process drawing (sectional drawing) which shows an example of the manufacturing method of an actuator. It is process drawing (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 a figure for demonstrating the conventional actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Actuator 1, 11 ... 2nd mass part 12, 13 ... End part 2 ... 1st mass part 21 ... Light reflection part 3 ... Supporting part 4 ... 2nd elastic connection part 41 ...... Pivot center axis 42 ...... Piezoresistive element 5 ...... First elastic connecting part 51 ...... Protrusions 52 and 53 ...... External electrodes 56 and 57 ...... Group electrodes 6 ...... Counter substrate 61 ...... Opening part 62 ...... Concavity 63 ...... Metal mask 7 ...... Vibrating body 70 ...... Connecting members 71 to 76 ...... Piezoelectric elements 77 and 78 ...... Electrode 30 ...... Connecting member 31 ...... Base part 32 ...... Supporting part 60 ...... Glass Substrate 9 …… Reinforcement plate 90 …… Substrate 105 …… Silicon substrate 110 …… Structure 140 …… Structure 150 …… Structure 200 …… Spacer 300 …… Moving electrode plate 300a …… Both ends fixed portion 300b …… Torsion Bar 300c ...... movable Pole portion 400 ...... fixed electrode 500 ...... power 600 ...... switch 1000 ...... glass substrate A, B, C ...... direction L1 to L5 ...... distance S ...... point S1, S2 ...... position T1, T2 ...... interval

Claims (16)

A first mass part;
A second mass part;
A pair of layers provided at positions corresponding to both ends of the second mass part, each having a laminated structure in which piezoelectric elements are laminated, and driven and vibrated by applying an alternating voltage to each piezoelectric element. Vibration body of
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. ,
An actuator characterized in that the second mass part is driven by the vibration in the thickness direction of the piezoelectric element due to the piezoelectric longitudinal effect of the vibrating body, and the first mass part is rotated accordingly. A first mass part;
A pair of second mass parts respectively provided on both sides 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 pair of vibrating bodies having a laminated structure in which piezoelectric elements are laminated, and being driven and vibrated by applying an alternating voltage to the piezoelectric elements;
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
One pair of vibrating bodies of the two pairs of vibrating bodies is provided at positions corresponding to both ends of one second mass section of the pair of second mass sections, respectively. And
The other pair of vibrating bodies of the two pairs of vibrating bodies is provided at positions corresponding to both ends of the other second mass section of the pair of second mass sections. And
The actuator, wherein each of the second mass parts is driven by the vibration in the thickness direction of the piezoelectric element due to the piezoelectric longitudinal effect of the vibrator, and the first mass part is rotated accordingly.   3. The actuator according to claim 2, wherein the two pairs of vibrating bodies are configured to be able to drive the pair of second mass parts synchronously.   4. The actuator according to claim 1, wherein each of the pair of vibrating bodies is provided substantially in line symmetry with respect to a central axis about which the second mass unit rotates in a plan view.   The phase difference between an alternating voltage applied to the piezoelectric element of one vibrating body of the pair of vibrating bodies and an alternating voltage applied to the piezoelectric element of the other vibrating body is 180 °. The actuator according to any one of 1 to 4. A counter substrate provided to face the second mass part with a gap therebetween;
6. The actuator according to claim 1, wherein each of the pair of vibrating bodies is fixed to a portion corresponding to the second mass portion of the counter substrate. The counter substrate is provided with a recess,
The actuator according to claim 6, wherein each of the pair of vibrators is inserted into and fixed to the recess. A reinforcing plate is provided between the support portion and the counter substrate,
The actuator according to claim 6 or 7, wherein the support portion and the counter substrate are joined to each other via the reinforcing plate. A protrusion is provided on one or both of the pair of vibrating bodies and the second mass part,
The actuator according to any one of claims 1 to 8, wherein each of the pair of vibrating bodies is configured to transmit a driving force to the second mass unit via the protrusion.   The position of the most displaced part of the second mass part when the second mass part is most rotated in one direction by the vibration of the pair of vibrators, and the vibration of the pair of vibrators Thus, the length of the protrusion is made longer than the distance from the position of the most displaced part of the second mass part when the second mass part is most rotated in the direction opposite to the one direction. Item 10. The actuator according to Item 9.   11. The actuator according to claim 10, wherein the most displaced portion of the second mass portion is an end portion in a direction substantially perpendicular to a central axis around which the second mass portion rotates.   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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