JP2008228444A - Actuator, optical scanner, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator in which a movable plate can be rotated on each of an X-axis and a Y-axis perpendicular to the X-axis while realizing cost reduction and miniaturization, and to provide an optical scanner and an image forming apparatus. <P>SOLUTION: The actuator 1 has a first vibration system 21 equipped with a driving member 211; a second vibration system 22 equipped with a movable plate 221; a first soft magnetic body 61 provided at a position spaced from the X-axis of the driving member 211; a second soft magnetic body 62 provided at a position spaced from the Y-axis of the movable plate 221; and a coil 63 provided so as to oppose the first soft magnetic body 61 and the second soft magnetic body 62. The actuator 1 is configured so that the movable plate 221 can be rotated on the X- and Y-axes by applying a periodically changing voltage in which a first voltage and a second voltage having frequencies different from each other are superimposed, to the coil 63. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an actuator, an optical scanner, and an image forming apparatus.

For example, an optical scanner that two-dimensionally scans light is disclosed as an optical scanner for performing drawing by optical scanning with a printer or the like (see, for example, Patent Document 1).
The optical scanner of Patent Document 1 includes a frame-shaped outer movable plate, a pair of first torsion bars that pivotally support the outer movable plate around the X axis (rotation), and an outer movable plate. A scanner body including an inner movable plate provided on the inner side, and a pair of second torsion bars that pivotally support the inner movable plate about a Y axis orthogonal to the X axis; an outer movable plate; It has a pair of drive coils provided on each of the inner movable plates, and a pair of permanent magnets provided so as to face each other through the scanner body.
However, since such an optical scanner is provided with a pair of permanent magnets so as to face each other through the optical scanner body, it is difficult to reduce the size of the optical scanner. Further, since one drive coil is provided for each of the outer movable plate and the inner movable plate, it is difficult to reduce the cost.

JP-A-8-322227

  An object of the present invention is to provide an actuator, an optical scanner, and an image forming apparatus capable of rotating a movable plate around each of an X axis and a Y axis orthogonal to the X axis while reducing cost and size. It is to provide.

Such an object is achieved by the present invention described below.
The actuator of the present invention includes a frame-shaped drive member and a pair of first shaft members that support the drive member so that the drive member can be rotated about the X axis. A first vibration system;
A pair of movable plates provided inside the drive member and a pair of both ends of the movable plate supported by the drive member so that the movable plate can be rotated about a Y axis orthogonal to the X axis. A second vibration system composed of a second shaft member;
The first soft magnetic body provided on the drive member, the second soft magnetic body provided on the movable plate, and the first soft magnetic body and the second soft magnetic body so as to face each other. Drive means comprising a provided coil and voltage applying means for applying a voltage to the coil;
The first soft magnetic body is provided at a position separated from the X axis of the driving member in a plan view of the movable plate,
The second soft magnetic body is provided at a position separated from the Y axis of the movable plate in a plan view of the movable plate,
The voltage applying unit superimposes the first voltage and the second voltage on a voltage generator that generates a first voltage and a second voltage that change periodically and have different frequencies. A voltage superimposing unit, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby rotating the movable plate around the X axis at the frequency of the first voltage, It is configured to rotate around the Y axis at a voltage frequency of
Accordingly, the movable plate is rotated around the X axis at the frequency of the first voltage and is rotated around the Y axis at the frequency of the second voltage while reducing cost and size. An actuator that can be provided can be provided.

In the actuator according to the aspect of the invention, it is preferable that the first soft magnetic body is provided at a portion of the driving member that is located distal to the X axis in a plan view of the movable plate.
Thus, under the same voltage, the drive member is rotated around the X axis as compared with the case where the first soft magnetic body is provided at a position proximal to the X axis of the drive member. The power to move increases. Therefore, the rotation angle of the drive member can be increased while achieving power saving of the actuator.

In the actuator according to the aspect of the invention, it is preferable that the first soft magnetic body is provided on the Y axis of the driving member in a plan view of the movable plate.
Thereby, it is possible to prevent the first shaft member from being bent in a direction perpendicular to the X axis and the Y axis when the actuator is driven. That is, deformation other than the torsional deformation around the X axis of each first shaft member can be suppressed. As a result, the drive member can be smoothly rotated around the X axis.

In the actuator according to the aspect of the invention, it is preferable that the first soft magnetic body is provided on a surface of the driving member facing the coil.
Thereby, since the separation distance between the first soft magnetic body and the coil can be shortened, the actuator can be reduced in size and power can be saved.
In the actuator according to the aspect of the invention, it is preferable that the second soft magnetic body is provided at a portion located distal to the Y axis of the plate surface of the movable plate in a plan view of the movable plate.
Thus, under the same voltage, the movable plate is rotated around the Y axis as compared with the case where the second soft magnetic body is provided at a position proximal to the Y axis of the movable plate. The power to move increases. For this reason, the rotational angle of the movable plate can be increased while reducing the power consumption of the actuator.

In the actuator according to the aspect of the invention, it is preferable that the second soft magnetic body is provided on the X axis of the movable plate in a plan view of the movable plate.
Thereby, when the actuator is driven, the second shaft member can be prevented from being bent in a direction perpendicular to the X axis and the Y axis. That is, deformation other than torsional deformation around the Y axis of each second shaft member can be suppressed. As a result, the movable plate can be smoothly rotated about the Y axis.

In the actuator according to the aspect of the invention, it is preferable that the first soft magnetic body is provided on a surface of the movable plate facing the coil.
As a result, the distance between the second soft magnetic body and the coil can be shortened, so that the actuator can be reduced in size and power can be saved.
In the actuator according to the aspect of the invention, it is preferable that the coil is provided so as to surround the first soft magnetic body and the second soft magnetic body in a plan view of the movable plate.
Accordingly, each of the first soft magnetic body and the second soft magnetic body can be magnetized by a magnetic field generated from the coil (that is, one coil). As a result, the actuator can be reduced in size and cost.

In the actuator of the present invention, it is preferable that the frequency of the second voltage is equal to the resonance frequency of the second vibration system, and the frequency of the first voltage is different from the resonance frequency of the first vibration system. .
Accordingly, the movable plate can be rotated about the Y axis at the second voltage frequency while the movable plate is rotated about the X axis at the first voltage frequency.

In the actuator of the present invention, it is preferable that each of the first voltage and the second voltage is applied in a pulse shape.
Accordingly, the movable plate can be effectively rotated around the Y axis at the frequency of the second voltage while being rotated around the X axis at the frequency of the first voltage.
In the actuator according to the aspect of the invention, it is preferable that the movable plate has a light reflecting portion having light reflectivity provided on a surface opposite to the second soft magnetic body.
Accordingly, the actuator can be used as an optical device provided in an image forming apparatus such as a laser printer, a barcode reader, a scanning confocal laser microscope, or an imaging display.

The optical scanner of the present invention includes a frame-shaped drive member and a pair of first shaft members that support the drive member so that the drive member can be rotated about the X axis. A first vibration system,
A movable plate provided on the inner side of the driving member and provided with a light reflecting portion having light reflectivity; and the movable plate is configured to be rotatable about a Y axis perpendicular to the X axis. A second vibration system composed of a pair of second shaft members that are both-side supported by the drive member;
The first soft magnetic body provided on the drive member, the second soft magnetic body provided on the movable plate, and the first soft magnetic body and the second soft magnetic body so as to face each other. Drive means comprising a provided coil and voltage applying means for applying a voltage to the coil;
The first soft magnetic body is provided at a position separated from the X axis of the driving member in a plan view of the movable plate,
The second soft magnetic body is provided at a position separated from the Y axis of the movable plate in a plan view of the movable plate,
The voltage applying unit superimposes the first voltage and the second voltage on a voltage generator that generates a first voltage and a second voltage that change periodically and have different frequencies. A voltage superimposing unit, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby rotating the movable plate around the X axis at the frequency of the first voltage, It is configured to rotate around the Y axis at a voltage frequency of 2 and to scan the light reflected by the light reflecting portion two-dimensionally.
Accordingly, the movable plate is rotated around the X axis at the frequency of the first voltage and rotated around the Y axis at the frequency of the second voltage while reducing the cost and size. It is possible to provide an optical scanner capable of scanning light two-dimensionally.

The image forming apparatus according to the present invention includes a frame-shaped drive member and a pair of first shaft members that support the drive member so that the drive member can be rotated about the X axis. A first vibration system,
A movable plate provided on the inner side of the driving member and provided with a light reflecting portion having light reflectivity; and the movable plate is configured to be rotatable about a Y axis perpendicular to the X axis. A second vibration system composed of a pair of second shaft members that are both-side supported by the drive member;
The first soft magnetic body provided on the drive member, the second soft magnetic body provided on the movable plate, and the first soft magnetic body and the second soft magnetic body so as to face each other. Drive means comprising a provided coil and voltage applying means for applying a voltage to the coil;
The first soft magnetic body is provided at a position separated from the X axis of the driving member in a plan view of the movable plate,
The second soft magnetic body is provided at a position separated from the Y axis of the movable plate in a plan view of the movable plate,
The voltage applying unit superimposes the first voltage and the second voltage on a voltage generator that generates a first voltage and a second voltage that change periodically and have different frequencies. A voltage superimposing unit, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby rotating the movable plate around the X axis at the frequency of the first voltage, And an optical scanner configured to rotate around the Y-axis at a voltage frequency of 2 and to scan two-dimensionally the light reflected by the light reflecting portion.
Accordingly, the movable plate is rotated around the X axis at the frequency of the first voltage and rotated around the Y axis at the frequency of the second voltage while reducing the cost and size. It is possible to provide an image forming apparatus including an optical scanner capable of two-dimensionally scanning light.

Hereinafter, preferred embodiments of an actuator, an optical scanner, and an image forming apparatus of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a plan view showing a preferred 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 block diagram showing driving means provided in the actuator shown in FIG. FIG. 4 is a diagram illustrating an example of a voltage generated in the first voltage generation unit and the second voltage generation unit illustrated in FIG. 3. In the following, for convenience of explanation, the front side of the paper in FIG. 1 is called “up”, the back side of the paper is called “down”, the right side is called “right”, the left side is called “left”, and the upper side in FIG. The upper side, the lower side is called “lower”, the right side is called “right”, and the left side is called “left”.

As shown in FIG. 1 and FIG. 2, the actuator 1 includes a base 2 including a first vibration system 21 and a second vibration system 22, a support substrate 3 that supports the base 2 via a bonding layer 4, A counter substrate 5 facing the base body 2 via the support substrate 3 and a driving means 6 for driving the first vibration system 21 and the second vibration system 22 are provided.
As shown in FIG. 1, the base 2 includes a frame-shaped support portion 23, a first vibration system 21 supported by the support portion 23, and a second vibration system 22 supported by the first vibration system 21. And.

  The first vibration system 21 includes a frame-shaped drive member 211 provided inside the support portion 23, and a pair of first shaft members 212 and 213 that support the drive member 211 on the support portion 23. It is configured. The second vibration system 22 includes a movable plate 221 provided inside the drive member 211 and a pair of second shaft members 222 and 223 that support the movable plate 221 on both sides of the drive member 211. Has been.

  The drive member 211 has an annular shape in a plan view of FIG. 1 (that is, a plan view of the movable plate 221). However, the shape of the drive member 211 is not particularly limited as long as it has a frame shape. A first soft magnetic body 61, which will be described later, is fixed to the lower surface of the drive member 211. Such a drive member 211 is supported at both ends on the support portion 23 by a pair of first shaft members 212 and 213.

  Each of the first shaft members 212 and 213 has a longitudinal shape and can be elastically deformed. The first shaft members 212 and 213 connect the drive member 211 and the support portion 23 so that the drive member 211 can rotate with respect to the support portion 23, respectively. Such first shaft members 212 and 213 are provided coaxially with each other, and the drive member 211 is located with respect to the support portion 23 around this axis (hereinafter referred to as “rotation center axis X”). It is configured to rotate.

  The movable plate 221 formed inside the drive member 211 has a circular shape in plan view of FIG. However, the shape of the movable plate 221 is not particularly limited, and may be, for example, an elliptical shape or a quadrangular shape in plan view of FIG. On the upper surface of the movable plate 221, a light reflecting portion 221a having light reflectivity is formed. On the other hand, a second soft magnetic body 62 described later is fixed to the lower surface of the movable plate 221. The movable plate 221 is supported at both ends by the drive member 211 by a pair of second shaft members 222 and 223.

  Each of the second shaft members 222 and 223 has a longitudinal shape and can be elastically deformed. The second shaft members 222 and 223 connect the movable plate 221 and the drive member 211 so that the movable plate 221 can rotate with respect to the drive member 211. Such second shaft members 222 and 223 are provided coaxially with each other, and the movable plate 221 with respect to the drive member 211 is centered on this shaft (hereinafter referred to as “rotation center axis Y”). It is configured to rotate.

  As shown in FIG. 1, the rotation center axis X and the rotation center axis Y are axes orthogonal to each other. That is, the angle formed by the rotation center axis X and the rotation center axis Y is 90 degrees. Further, the respective centers of the drive member 211 and the movable plate 221 are located on the intersection of the rotation center axis X and the rotation center axis Y in the plan view of FIG. Hereinafter, for convenience of explanation, an intersection of the rotation center axis X and the rotation center axis Y is also referred to as an “intersection point G”.

  Such a base body 2 is made of, for example, silicon as a main material, and includes a movable plate 221, second shaft members 222 and 223, a drive member 211, first shaft members 212 and 213, and a support. The part 23 is integrally formed. By using silicon as a main material, it is possible to realize excellent rotation characteristics and to exhibit excellent durability. Further, fine processing (processing) is possible, and the actuator 1 can be miniaturized.

  The base 2 is formed from a substrate having a laminated structure such as an SOI substrate, a movable plate 221, second shaft members 222 and 223, a drive member 211, first shaft members 212 and 213, and a support portion 23. And may be formed. At that time, the movable plate 221, the second shaft members 222 and 223, the drive member 211, the first shaft members 212 and 213, and the support portion 23 are integrated with each other so as to be integrated. It is preferable to be composed of one layer.

As shown in FIG. 2, the base 2 as described above is bonded to the support substrate 3 via the bonding layer 4. Such a support substrate 3 is made of, for example, glass or silicon as a main material. The support substrate 3 has substantially the same shape as the support portion 23 in a plan view of the movable plate 221 (that is, has a frame shape). However, the shape of the support substrate 3 is not particularly limited as long as the base 2 can be supported. Further, depending on the shape of the support portion 23 and the like, the support substrate 3 may be omitted.
The bonding layer 4 formed between the support substrate 3 and the base 2 is made of, for example, glass, silicon, or SiO2 as a main material. However, such a bonding layer 4 may be omitted. That is, the base 2 and the support substrate 3 may be directly joined.

As shown in FIG. 2, a counter substrate 5 is provided so as to face the base 2 via the support substrate 3. Such a counter substrate 5 is made of, for example, glass or silicon as a main material. On the upper surface of the counter substrate 5, a coil 63 for magnetizing each of the first soft magnetic body 61 and the second soft magnetic body 62 is provided. The coil 63 is electrically connected to the voltage application unit 64. The first soft magnetic body 61, the second soft magnetic body 62, the coil 63, and the voltage applying means 64 constitute the driving means 6.
The first soft magnetic body 61 has a circular shape in plan view of FIG. However, the shape of the first soft magnetic body 61 is not particularly limited, and may be elliptical or quadrangular in plan view in FIG.

As shown in FIG. 1, the first soft magnetic body 61 is fixed to the lower surface of the drive member 211. That is, the first soft magnetic body 61 is fixed to the surface of the driving member 211 that faces the coil 63. Thereby, since the distance between the first soft magnetic body 61 and the coil 63 can be shortened, the actuator 1 can be reduced in size and power can be saved.
Further, the first soft magnetic body 61 is fixed to a portion located distal to the rotation center axis X of the drive member 211 in the plan view of FIG. Thereby, under the same voltage, the drive member 211 is moved to the rotation center axis as compared with the case where the first soft magnetic body 61 is provided in a portion located proximal to the rotation center axis X of the drive member 211. The force to rotate around X increases. Therefore, the rotation angle of the drive member 211 can be increased while achieving power saving of the actuator 1.

  Further, the first soft magnetic body 61 is fixed to a portion located on the rotation center axis Y of the drive member 211 in the plan view of FIG. In other words, the first soft magnetic body 61 is fixed to the central portion of the drive member 211 in the rotation central axis X direction in a plan view of FIG. Thereby, when the actuator 1 is driven, the first shaft members 212 and 213 can be prevented from being bent in directions orthogonal to the rotation center axis X and the rotation center axis Y. . That is, deformation other than the torsional deformation around the rotation center axis X of the first shaft members 212 and 213 can be suppressed. As a result, the drive member 211 can be smoothly rotated about the rotation center axis X, and the actuator 1 can exhibit desired vibration characteristics.

  The first soft magnetic body 61 has been described above. However, if the drive member 211 can be rotated around the rotation center axis X by magnetizing the first soft magnetic body 61, the first soft magnetic body 61 will be described. The arrangement of the body 61 is not particularly limited. For example, the first soft magnetic body 61 may be fixed to a portion located proximal to the rotation center axis X of the drive member 211 in the plan view of FIG. You may adhere to the edge part of the central axis X direction. Further, the first soft magnetic body 61 may be fixed to the upper surface of the drive member 211.

On the other hand, the second soft magnetic body 62 fixed to the movable plate 221 has a circular shape in a plan view of FIG. However, the shape of the second soft magnetic body 62 is not particularly limited, and may be an elliptical shape or a quadrangular shape in plan view.
As shown in FIG. 1, the second soft magnetic body 62 is fixed to the lower surface of the movable plate 221. That is, the second soft magnetic body 62 is fixed to the surface of the movable plate 221 that faces the coil 63. Thereby, since the separation distance between the second soft magnetic body 62 and the coil 63 can be shortened, the actuator 1 can be reduced in size and power can be saved. Further, since the first soft magnetic body 61 is fixed to the same surface as the surface to which the first soft magnetic body 61 is fixed, the manufacturing of the actuator 1 can be simplified. In addition, since the second soft magnetic body 62 is fixed to the surface of the movable plate 221 opposite to the light reflecting portion 221a, the second soft magnetic body 62 inhibits light scanning by the light reflecting portion 221a. Can be reliably prevented.

  Further, the second soft magnetic body 62 is fixed to a portion located distal to the rotation center axis Y of the movable plate 221 in the plan view of FIG. Thereby, under the same voltage, the movable plate 221 is moved to the rotation center axis as compared with the case where the second soft magnetic body 62 is provided in a portion located proximal to the rotation center axis Y of the movable plate 221. The force to rotate around Y increases. Therefore, the rotation angle of the movable plate 221 can be increased while achieving power saving of the actuator 1.

  Further, the second soft magnetic body 62 is fixed to a portion located on the rotation center axis X of the movable plate 221 in the plan view of FIG. In other words, the second soft magnetic body 62 is fixed to the central portion of the movable plate 221 in the rotation central axis Y direction in the plan view of FIG. Thereby, when the actuator 1 is driven, the second shaft members 222 and 223 can be prevented from being bent in directions orthogonal to the rotation center axis X and the rotation center axis Y. . That is, deformation other than torsional deformation around the rotation center axis Y of the second shaft members 222 and 223 can be suppressed. As a result, the movable plate 221 can be smoothly rotated about the rotation center axis Y, and the actuator 1 can exhibit desired vibration characteristics.

The second soft magnetic body 62 has been described above. However, if the movable plate 221 can be rotated around the rotation center axis Y by magnetizing the second soft magnetic body 62, the second soft magnetic body 62 can be rotated. The arrangement of the body 62 is not particularly limited. For example, the second soft magnetic body 62 may be fixed to a portion located proximal to the rotation center axis Y of the movable plate 221 in the plan view of FIG. You may adhere to the edge part of the central axis Y direction. Further, the first soft magnetic body 61 may be fixed to the upper surface of the movable plate 221.
Each of the first soft magnetic body 61 and the second soft magnetic body 62 is composed of a soft magnetic material as a main material. Such a soft magnetic material is not particularly limited, and Fe, various Fe alloys (silicon iron, permalloy, amorphous, Sendust) and the like can be suitably used.

A coil 63 is formed so as to surround the first soft magnetic body 61 and the second soft magnetic body 62 in a plan view of FIG. Accordingly, the first soft magnetic body 61 and the second soft magnetic body 62 can be magnetized by a magnetic field generated from the coil 63 (that is, one coil). As a result, the actuator 1 can be reduced in size and cost.
Such a coil 63 is electrically connected to the voltage applying means 64. Then, by applying a voltage to the coil 63 by the voltage applying means 64, a magnetic field having a magnetic flux in a direction orthogonal to the rotation center axis X and the rotation center axis Y is generated from the coil 63. Then, the first soft magnetic body 61 and the second soft magnetic body 62 magnetized by the magnetic field generated from the coil 63 are attracted to the coil 63, respectively.

  As shown in FIG. 3, the voltage applying means 64 includes a first voltage generator 641 that generates a first voltage V1 for rotating the movable plate 221 around the rotation center axis X, and a movable plate 221. A second voltage generator 642 for generating a second voltage V2 for rotating around the rotation center axis Y is superimposed on the first voltage V1 and the second voltage V2, and the voltage is applied to the coil 63. And a voltage superimposing section 643 for applying to the power supply.

As shown in FIG. 4A, the first voltage generator 641 generates a first voltage V1 (vertical scanning voltage) that periodically changes in a cycle T1. That is, the first voltage generator 641 generates the first voltage V1 having the frequency (1 / T1).
The first voltage V1 is applied in a pulse form. With such a first voltage V1, the actuator 1 can effectively perform vertical scanning (sub-scanning) of light. That is, the movable plate 221 can be effectively rotated around the rotation center axis X. However, each waveform of the first voltage V1 is not limited to this as long as the movable plate 221 can be rotated around the rotation center axis X.

  Here, the frequency (1 / T1) of the first voltage V1 is not particularly limited as long as it is a frequency suitable for vertical scanning, but is preferably 30 to 80 Hz (about 60 Hz). In the present embodiment, the frequency of the first voltage V1 is different from the torsional resonance frequency of the first vibration system 21 including the driving member 211 and the pair of first shaft members 212 and 213. It has been adjusted.

On the other hand, as shown in FIG. 4B, the second voltage generator 642 generates a second voltage V2 (horizontal scanning voltage) that periodically changes at a period T2 different from the period T1. . That is, the second voltage generator 642 generates the second voltage V2 having a frequency (1 / T2).
The second voltage V2 is applied in a pulse form. By such a second voltage V2, the actuator 1 can effectively perform horizontal scanning (main scanning) of light. That is, the movable plate 221 can be effectively rotated around the rotation center axis Y. However, the waveform of the second voltage V2 is not limited to this as long as the movable plate 221 can be rotated around the rotation central axis Y.

  Here, the frequency of the second voltage V2 is not particularly limited as long as it is different from the frequency of the first voltage V1 and is suitable for horizontal scanning, but is preferably 10 to 40 kHz. By setting the frequency of the second voltage V2 to 10 to 40 kHz and the frequency of the first voltage V1 to about 60 Hz, the movable plate 221 is pivoted smoothly at a frequency suitable for drawing on the display. It can be rotated around the axis X and the rotation center axis Y.

  In this way, by setting the frequency of the second voltage V2 to 100 to 1000 times the frequency of the first voltage V1, the movable plate 221 can smoothly move each of the rotation center axis X and the rotation center axis Y. It can be rotated around an axis. However, if the movable plate 221 can be rotated about each of the rotation center axis X and the rotation center axis Y, the relationship between the frequency of the first voltage V1 and the frequency of the second voltage V2 (the magnitude). Is not particularly limited.

  The frequency of the second voltage V2 is adjusted to be equal to the torsional resonance frequency of the second vibration system 22 constituted by the movable plate 221 and the pair of second shaft members 222 and 223. That is, the second vibration system 22 is designed (manufactured) so that its torsional resonance frequency is a frequency suitable for horizontal scanning. Thereby, the rotation angle of the movable plate 221 around the rotation center axis Y can be increased.

When the resonance frequency of the first vibration system 21 is f ₁ [Hz] and the resonance frequency of the second vibration system 22 is f ₂ [Hz], f ₁ and f ₂ are f ₂ > f. ₁ is preferably satisfied, and more preferably f ₂ ≧ 10f ₁ is satisfied. As a result, the movable plate 221 is more smoothly rotated around the rotation center axis X at the frequency of the second voltage V2 while being rotated more smoothly around the rotation center axis X. Can do.
The first voltage generation unit 641 and the second voltage generation unit 642 are connected to the control unit 7 and driven based on signals from the control unit 7. In addition, a voltage superimposing unit 643 is connected to the first voltage generating unit 641 and the second voltage generating unit 642.
The voltage superimposing unit 643 includes an adder 643 a for applying a voltage to the coil 63. The adder 643a receives the first voltage V1 from the first voltage generator 641 and receives the second voltage V2 from the second voltage generator 642, and superimposes them to apply to the coil 63. ing.

The actuator 1 having the above configuration is driven as follows.
In the present embodiment, as described above, the frequency of the first voltage V1 is set to a value different from the torsional resonance frequency of the first vibration system 21, and the frequency of the second voltage V2 is 2 is set to be equal to the torsional resonance frequency of the vibration system 22 and higher than the frequency of the first voltage V1 (for example, the frequency of the first voltage V1 is 60 Hz and the second voltage V2 Frequency is 15 kHz).

For example, the first voltage V1 as shown in FIG. 4A and the second voltage V2 as shown in FIG. 4B are superimposed and applied to the coil 63 (this superimposed voltage is expressed as “voltage V3 ”).
Then, a magnetic field (this magnetic field is referred to as “magnetic field A”) that attempts to attract the vicinity of the first soft magnetic body 61 of the driving member 211 to the coil 63 by a voltage corresponding to the first voltage V1 of the voltage V3. It occurs intermittently.

Here, in the plan view of FIG. 1, the first soft magnetic body 61 is fixed to a part of the drive member 211 that is away from the rotation center axis X. Therefore, by intermittently generating the magnetic field A, the first shaft members 212 and 213 are torsionally deformed, and the drive member 211 together with the movable plate 221 rotates around the rotation center axis X at the frequency of the first voltage V1. To turn.
Note that the frequency of the first voltage V1 is set to be extremely lower than the frequency of the second voltage V2. The resonance frequency of the first vibration system 21 is designed to be lower than the resonance frequency of the second vibration system 22 (for example, 1/10 or less of the resonance frequency of the second vibration system 22). That is, since the first vibration system 21 is designed to vibrate more easily than the second vibration system 22, the first vibration system 21 is rotated around the rotation center axis X by the first voltage V1. That is, it is possible to prevent the driving member 211 from rotating about the rotation center axis X by the second voltage V2.

On the other hand, a magnetic field (this magnetic field is referred to as “magnetic field B”) that tries to attract the vicinity of the second soft magnetic body 62 of the movable plate 221 to the coil 63 by a voltage corresponding to the second voltage V2 of the voltage V3. It occurs intermittently.
Here, in the plan view of FIG. 1, the second soft magnetic body 62 is fixed to a part of the movable plate 221 that is separated from the rotation center axis Y. Therefore, when the magnetic field B is intermittently generated, the movable plate 221 rotates about the rotation center axis Y at the frequency of the second voltage V2 while torsionally deforming the second shaft members 222 and 223.

The frequency of the second voltage V2 is equal to the torsional resonance frequency of the second vibration system 22. Therefore, the movable plate 221 can be predominantly rotated around the rotation central axis Y by the second voltage V2. That is, it is possible to prevent the movable plate 221 from rotating around the rotation center axis Y by the first voltage V1.
As described above, the actuator 1 applies the voltage V3 obtained by superimposing the first voltage V1 and the second voltage V2 to the coil 63, thereby moving the movable plate 221 around the rotation center axis X to the first. It is possible to rotate around the rotation center axis Y at the frequency of the second voltage V2 while rotating at the frequency of the voltage V1. Thereby, cost reduction and size reduction can be achieved, and the movable plate 221 can be rotated around the rotation center axis X and the rotation center axis Y.

In such an actuator 1, the design of the base 2, the first soft magnetic body 61, the second soft magnetic body 62, etc. is changed by appropriately changing the first voltage V 1 and the second voltage V 2. Thus, desired vibration characteristics can be obtained.
In addition, the first soft magnetic body 61 and the second soft magnetic body 62 are fixed to the base 2, and the coil 63 is provided so as to face the first soft magnetic body 61 and the second soft magnetic body 62. The thermal expansion of the base 2 due to the heat generated from the coil 63 by energization can be suppressed. That is, the actuator 1 can exhibit a desired vibration characteristic even when used continuously for a long time.

  Since the actuator 1 as described above includes the light reflecting portion 221a, for example, MEMS application sensors such as an acceleration sensor and an angular velocity sensor, a laser printer, a barcode reader, a scanning confocal laser microscope, and an imaging display. It can be used for an optical device such as an optical scanner, an optical switch, an optical attenuator provided in an image forming apparatus. Since the optical scanner of the present invention has the same configuration as the actuator described above, the description thereof is omitted.

  Here, based on FIG. 5, a case where the actuator 1 is used as an optical scanner of an imaging display will be described as an example of an image forming apparatus. The longitudinal direction of the screen S is referred to as “lateral direction”, and the direction perpendicular to the longitudinal direction is referred to as “vertical direction”. Further, the rotation center axis X is parallel to the horizontal direction of the screen S, and the rotation center axis Y is parallel to the vertical direction of the screen S.

The image forming apparatus (projector) 9 includes a light source device 91 that emits light such as a laser, a plurality of dichroic mirrors 92, 92, and 92, and an actuator 1.
The light source device 91 includes a red light source device 911 that emits red light, a blue light source device 912 that emits blue light, and a green light source device 913 that emits green light.
Each dichroic mirror 92 is an optical element that combines light emitted from each of the red light source device 911, the blue light source device 912, and the green light source device 913.

  Such a projector 9 combines light emitted from the light source device 91 (red light source device 911, blue light source device 912, green light source device 913) by a dichroic mirror 92 based on image information from a host computer (not shown). Then, the combined light is two-dimensionally scanned by the actuator 1 to form a color image on the screen S.

During the two-dimensional scanning, the light reflected by the light reflecting portion 221a due to the rotation of the movable plate 221 of the actuator 1 around the rotation central axis Y is scanned (main scanning) in the horizontal direction of the screen S. On the other hand, the light reflected by the light reflecting portion 221 a due to the rotation of the movable plate 221 of the actuator 1 around the rotation center axis X is scanned (sub-scanned) in the vertical direction of the screen S.
In FIG. 5, the light synthesized by the dichroic mirror 92 is scanned two-dimensionally by the actuator 1, and then the light is reflected by the fixed mirror M and then an image is formed on the screen S. However, the fixed mirror M may be omitted, and the screen S may be directly irradiated with light two-dimensionally scanned by the actuator 1.

  Although the actuator, optical scanner, and image forming apparatus of the present invention have been described based on the illustrated embodiments, the present invention is not limited to this. For example, in the actuator, optical scanner, and image forming apparatus of the present invention, the configuration of each part can be replaced with an arbitrary configuration that exhibits the same function, and an arbitrary configuration can be added.

In the above-described embodiment, the actuator has a substantially symmetric shape with respect to the Y axis and the X axis, but may be asymmetrical.
In the above-described embodiment, one drive member is fixed with one first soft magnetic body and the movable plate 221 is fixed with one second soft magnetic body. The number of the first soft magnetic bodies and the number of the second soft magnetic bodies is not particularly limited as long as 221 can be rotated around each of the rotation center axis X and the rotation center axis Y.

  In the above-described embodiment, the coil is formed so as to surround the first soft magnetic body and the second soft magnetic body in a plan view of the movable plate. There is no particular limitation as long as each of the two soft magnetic bodies can be magnetized. For example, it may be formed so as to surround the drive member 211 in a plan view of the movable plate. By forming the coil in this manner, it is possible to reliably prevent the drive member and the movable plate from contacting the coil, so that the first soft magnetic body, the second soft magnetic body, and the coil are more Can be approached. As a result, the actuator can be reduced in size and power can be saved.

It is a top view which shows suitable embodiment of the actuator of this invention. It is the sectional view on the AA line in FIG. It is a block diagram which shows the voltage application means of the drive means with which the actuator shown in FIG. 1 is provided. It is a figure which shows an example of the voltage generated in the 1st voltage generation part shown in FIG. 3, and a 2nd voltage generation part. 1 is a schematic view showing an image forming apparatus of the present invention.

Explanation of symbols

  1 ... Actuator 2 ... Base 21 ... 1st vibration system 211 ... Drive member 212, 213 ... 1st shaft member 22 ... 2nd vibration system 221 ... Movable Plate 221a ··· Light reflecting portion 222, 223 ··· Second shaft member 23 ··· Support portion 3 ··· Support substrate 4 · · · Bonding layer 5 · · · Counter substrate 6 · · · Driving means 61 1st soft magnetic material 62 2nd soft magnetic material 63 Coil 64 Voltage applying means 641 First voltage generator 642 2nd voltage generation Section 643 ... Voltage superposition section 643a ... Adder 7 ... Control section 9 ... Image forming device (projector) 91 ... Light source device 911 ... Red light source device 912 ... Blue light source device 913 ... Green light source 92 ... Dichroic Ra M ‥‥‥ fixed mirror S ‥‥‥ screen X, Y ‥‥‥ rotational axis

Claims (13)

A first vibration system including a frame-shaped drive member and a pair of first shaft members that support the drive member so that the drive member can rotate about the X axis; ,
A pair of movable plates provided inside the drive member and a pair of both ends of the movable plate supported by the drive member so that the movable plate can be rotated about a Y axis orthogonal to the X axis. A second vibration system composed of a second shaft member;
The first soft magnetic body provided on the drive member, the second soft magnetic body provided on the movable plate, and the first soft magnetic body and the second soft magnetic body so as to face each other. Drive means comprising a provided coil and voltage applying means for applying a voltage to the coil;
The first soft magnetic body is provided at a position separated from the X axis of the driving member in a plan view of the movable plate,
The second soft magnetic body is provided at a position separated from the Y axis of the movable plate in a plan view of the movable plate,
The voltage applying unit superimposes the first voltage and the second voltage on a voltage generator that generates a first voltage and a second voltage that change periodically and have different frequencies. A voltage superimposing unit, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby rotating the movable plate around the X axis at the frequency of the first voltage, An actuator configured to rotate around the Y axis at a voltage frequency of   2. The actuator according to claim 1, wherein the first soft magnetic body is provided in a portion of the driving member that is located distal to the X axis in a plan view of the movable plate.   3. The actuator according to claim 1, wherein the first soft magnetic body is provided on the Y axis of the drive member in a plan view of the movable plate.   The actuator according to any one of claims 1 to 3, wherein the first soft magnetic body is provided on a surface of the driving member facing the coil.   The said 2nd soft magnetic body is provided in the site | part located far from the said Y-axis of the plate | board surface of the said movable plate by planar view of the said movable plate. Actuator.   The actuator according to claim 1, wherein the second soft magnetic body is provided on the X axis of the movable plate in a plan view of the movable plate.   The actuator according to claim 1, wherein the first soft magnetic body is provided on a surface of the movable plate facing the coil.   The actuator according to claim 1, wherein the coil is provided so as to surround the first soft magnetic body and the second soft magnetic body in a plan view of the movable plate.   The frequency of the second voltage is equal to the resonance frequency of the second vibration system, and the frequency of the first voltage is different from the resonance frequency of the first vibration system. The actuator described.   The actuator according to claim 1, wherein each of the first voltage and the second voltage is applied in a pulse shape.   The actuator according to claim 1, wherein the movable plate includes a light reflecting portion having light reflectivity provided on a surface opposite to the second soft magnetic body. A first vibration system including a frame-shaped drive member and a pair of first shaft members that support the drive member so that the drive member can rotate about the X axis; ,
A movable plate provided on the inner side of the driving member and provided with a light reflecting portion having light reflectivity; and the movable plate is configured to be rotatable about a Y axis perpendicular to the X axis. A second vibration system composed of a pair of second shaft members that are both-side supported by the drive member;
The first soft magnetic body provided on the drive member, the second soft magnetic body provided on the movable plate, and the first soft magnetic body and the second soft magnetic body so as to face each other. Drive means comprising a provided coil and voltage applying means for applying a voltage to the coil;
The first soft magnetic body is provided at a position separated from the X axis of the driving member in a plan view of the movable plate,
The second soft magnetic body is provided at a position separated from the Y axis of the movable plate in a plan view of the movable plate,
The voltage applying unit superimposes the first voltage and the second voltage on a voltage generator that generates a first voltage and a second voltage that change periodically and have different frequencies. A voltage superimposing unit, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby rotating the movable plate around the X axis at the frequency of the first voltage, The optical scanner is configured to rotate around the Y axis at a frequency of a voltage of 2 and to scan light reflected by the light reflecting portion two-dimensionally. A first vibration system including a frame-shaped drive member and a pair of first shaft members that support the drive member so that the drive member can rotate about the X axis; ,
A movable plate provided on the inner side of the driving member and provided with a light reflecting portion having light reflectivity; and the movable plate is configured to be rotatable about a Y axis perpendicular to the X axis. A second vibration system composed of a pair of second shaft members that are both-side supported by the drive member;
The first soft magnetic body provided on the drive member, the second soft magnetic body provided on the movable plate, and the first soft magnetic body and the second soft magnetic body so as to face each other. Drive means comprising a provided coil and voltage applying means for applying a voltage to the coil;
The first soft magnetic body is provided at a position separated from the X axis of the driving member in a plan view of the movable plate,
The second soft magnetic body is provided at a position separated from the Y axis of the movable plate in a plan view of the movable plate,
The voltage applying unit superimposes the first voltage and the second voltage on a voltage generator that generates a first voltage and a second voltage that change periodically and have different frequencies. A voltage superimposing unit, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby rotating the movable plate around the X axis at the frequency of the first voltage, An image forming apparatus comprising: an optical scanner configured to rotate around the Y axis at a voltage frequency of 2 and to scan light reflected by the light reflecting portion two-dimensionally.

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