JP2010019934A - Actuator, optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact actuator which turns a movable plate around X-axis and Y-axis with smaller consumption of electric power, and also to provide an optical scanner and an image forming apparatus. <P>SOLUTION: The actuator comprises: an oscillation system forming substrate (2) on which an oscillation structure body which supports a movable plate turnably around first and second axes is formed; a magnetic body (61) which is provided on the oscillation structure body so that two magnetic poles may be disposed interposing the movable plate and the line connecting the two magnetic poles may be tilted with respect to the first and the second axes, respectively; sealing members (10, 11) which form a closed space operably enclosing the movable plate, the oscillation structure body and the magnetic body and keep the closed space in an atmosphere having a pressure equal to or lower than the atmospheric pressure; and a driving coil (62) which is provided at a position opposing to the magnetic body on the outer side face of the sealing members. <P>COPYRIGHT: (C)2010,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.

JP-A-8-322227

However, since such an optical scanner is provided with a pair of permanent magnets so as to face each other via the optical scanner body, it is difficult to reduce the size of the optical scanner. Further, since current is applied to one drive coil provided on each of the outer movable plate and the inner movable plate, there is a possibility that the movable plate is deformed by heat generation. In particular, this deformation becomes large in order to obtain a large rotation. In order to reduce the drive current and obtain a large rotation, it is conceivable to reduce the pressure in the package. However, since the wiring to the drive coil is drawn out of the package, the low pressure package can maintain the reduced pressure state. difficult. In addition, since the wiring lead-out and two large permanent magnets are arranged in the package, the package volume is large and the structure is unsuitable for maintaining a reduced pressure state.
Accordingly, an object of the present invention is to provide an actuator, an optical scanner, and an image forming apparatus capable of rotating the movable plate largely around the X axis and the Y axis with lower power consumption while reducing the size. And

Such an object is achieved by the present invention described below.
The actuator of the present invention includes a vibration system forming substrate on which a vibration structure that supports the movable plate so as to be rotatable about the first and second axes is formed, and two magnetic poles arranged with the movable plate interposed therebetween. A magnetic body provided in the vibration structure, the movable plate, and the vibration structure so that a line segment connecting the two magnetic poles is inclined with respect to each of the first and second axes. And enclosing the magnetic body in an operative manner to form a closed space, and maintaining the closed space in an atmosphere reduced to a pressure lower than atmospheric pressure, and facing the magnetic body on the outer surface of the sealing member And a drive coil provided at a position to be provided. The magnetic material includes a permanent magnet, a soft magnetic material that easily becomes a magnet when a magnetic field is applied, and the like.

  With such a configuration, the resistance of air to the vibration operation of the movable plate and the vibration structure is reduced, and the movable plate can be vibrated at a higher frequency. In addition, by arranging the vibrating structure in a reduced pressure sealing member, more preferably in a vacuum state, resonance driving using a high Q value can be used, and power consumption can be reduced. In addition, the movable member and the vibration structure that do not require electrical wiring are arranged in the sealing member, and those that require electrical wiring such as a drive coil are arranged outside the sealing member. Since the sealing member is configured to be easily sealed so as to easily maintain a reduced pressure state (for example, vacuum), a vacuum package can be realized at low cost.

  Examples of the soft magnetic material include iron, silicon steel, permalloy, sendust, permendur, soft ferrite, and amorphous magnetic alloy, and are appropriately selected. The soft magnetic material becomes a magnet when a magnetic field is applied by the drive coil, generates a magnetic force with the magnetic field, and generates a force for driving the vibrating structure.

As described above, the drive coil is preferably provided directly below the magnetic body (permanent magnet) outside the sealing member.
Thereby, power saving and size reduction of the actuator can be achieved.
In the actuator according to the aspect of the invention, it is preferable that the coil is formed so as to surround an outer periphery of the driving member in a plan view of the movable plate.
Thereby, the separation distance between the coil and the permanent magnet can be made extremely small. As a result, the magnetic field generated from the coil can be efficiently applied to the permanent magnet. That is, power saving and downsizing of the actuator can be achieved.

  Furthermore, it is desirable that a getter film for absorbing the gas in the closed space is formed inside the sealing member. As a result, the gas remaining inside the substrate during the sealing is absorbed to increase the degree of vacuum, or the gas that has entered from the outside after sealing is adsorbed and removed to reduce the pressure in the sealing member (the degree of vacuum). Can be maintained.

The movable plate is provided with a reflective film, and a transparent window portion through which incident light to the reflective film and reflected light from the reflective film pass is formed in a part of the sealing member. It is desirable that the getter film is disposed as a light absorption film at least around the window. Thereby, irregular reflection by the sealing member can be avoided (measures against stray light).
As the material of the getter film described above, transition metals such as Zr, Ti, Nb, Ta, and V, or alloys or compounds thereof, Cr, Mn, Fe, Co, Ni, Al, Y, La, and rare earths are used. Alloys or compounds with at least one element selected from, for example, Ti-V, Zr-Al, Zr-V, Zr-Fe and Zr-Ni, ternary alloys, Zr-V-Fe and Zr-Co-rare earth Or a multi-component alloy. As the light absorption film, a black film of these materials, a black film such as GeN or TiN, or a getter film material is formed as a so-called moth-eye structure having a structure with little reflected light. Patterned ones can be used.

  It is desirable that the sealing member is formed by joining an upper sealing member and a lower sealing member, at least one of which has a recess. Thereby, the vibration system forming substrate can be sealed.

  It is desirable that the upper sealing member is glass, the vibration system forming substrate is silicon, and the lower sealing member is glass. Thereby, it can bond by anodic bonding in the state which accumulated the upper side sealing member, the vibration system formation board | substrate, and the upper side sealing member. By making the upper and lower sealing members into glass, the state of the vibration system forming substrate after joining can be confirmed from above and below, and appearance inspection and the like in the production process are easy.

  The vibration structure 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. The first vibration system, the movable plate provided on the inner side of the drive member, and the movable plate so that the movable plate can be rotated about a Y axis orthogonal to the X axis. And a second vibration system composed of a pair of second shaft members that are supported at both ends. Thereby, a movable plate that rotates around the X axis and the Y axis is obtained.

  Furthermore, voltage application means for applying a driving voltage to the coil is provided, the voltage application means generating a first alternating voltage and a second alternating voltage having different frequencies, and the first A voltage superimposing unit that superimposes the voltage and the second voltage, and applying the voltage superimposed by the voltage superimposing unit to the coil, thereby moving the movable plate at the frequency of the first voltage. It is desirable to be configured to rotate around the Y axis at the frequency of the second voltage while rotating around the axis. Thereby, the movable plate can be rotated around the X axis and the Y axis.

  The actuator of the present invention is convenient for use in an optical scanner that generates two-dimensional scanning light or an image forming apparatus that forms an image with two-dimensional scanning light. Provided is an image forming apparatus provided with an optical scanner capable of two-dimensionally scanning light by rotating the movable plate around each of the X axis and the Y axis while reducing the cost and size. can do. For example, it 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.

  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.

Example 1
FIG. 1 is a plan view showing a preferred embodiment of the actuator of the present invention, FIG. 2 is a plan view showing a vibration mechanism with the upper sealing member of the actuator of the present invention removed, and FIG. FIG. 4 is a cross-sectional view in the XX ′ direction (however, a driving member and a permanent magnet portion described later are shown in a cross section in the AA direction in the drawing), and FIG. 4 is a driving means provided in the actuator shown in FIG. FIG. 5 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. 4. In the following, for convenience of explanation, the front side in FIG. 2 is referred to as “up”, the back side in FIG. 2 is referred to as “down”, the right side is referred to as “right”, the left side is referred to as “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 FIGS. 1 and 3, the actuator 1 is roughly composed of a vibration system forming substrate 2, and an upper sealing substrate 10 and a lower sealing substrate 11 as sealing members for sealing the vibration system forming substrate 2. It is configured. Each of the upper sealing substrate 10 and the lower sealing substrate 11 is a concave body having a frame (projection) formed on the outer peripheral edge, and the concave portions of the upper sealing substrate 10 and the lower sealing substrate 11 are aligned with each other. Are combined (oppositely) to form a closed space. In this closed space, vibration structures (21 and 22 described later) of the vibration system forming substrate 2 are arranged. In this embodiment, the vibration system forming substrate 2 is made of silicon, and the upper sealing substrate 10 and the lower sealing substrate 11 are made of glass.

  The vibration system forming substrate 2 is superposed between the upper sealing substrate 10 and the lower sealing substrate 11 in a reduced pressure atmosphere (desirably, a so-called vacuum state in which the pressure is sufficiently reduced from atmospheric pressure). It is heated to such a degree that a high voltage is applied between the substrates 10 and 11 and bonding is performed by so-called anodic bonding. Note that the bonding between the substrates is not limited to this, and the substrates may be bonded together with a resin-based adhesive.

  In the closed space formed between the upper sealing substrate 10 and the lower sealing substrate 11, a film of a getter material that increases the degree of vacuum in the closed space by absorbing gas or combining with gas particles. 110 is formed. There are no particular restrictions on the location of the getter film 110 as long as it does not interfere with the operation of the vibrating structure. It may be provided on either side of the upper sealing substrate 10 and the lower sealing substrate 11. The getter film 110 increases the degree of vacuum and contributes to maintaining the degree of vacuum for a long period of time.

  In the embodiment of the present application, the getter film 110 is provided on the inner wall of the upper sealing substrate 10. The getter film 110 is previously provided on the upper sealing substrate 10 by vapor deposition, application, sintering, adhesion, or the like. For example, the main non-evaporable getter materials (also known in the art as NEG materials) are transition metals such as Zr, Ti, Nb, Ta, V, or their alloys or compounds and / or Cr, Mn Alloys or compounds with at least one element selected from Fe, Co, Ni, Al, Y, La and rare earths, for example, binary alloys, Ti-V, Zr-Al, Zr-V, Zr-Fe and Zr -Ni, ternary alloys, Zr-V-Fe and Zr-Co-rare earths, or multicomponent alloys.

  As shown in FIG. 1, a portion of the getter film 110 that faces the light reflecting portion (mirror) 221 a is opened, and a transparent window portion 120 through which light passes is formed by the transparent upper sealing substrate 10. In this window part 120, a light beam is incident on the light reflecting part 221a disposed in the closed space from the outside, and a reflected beam whose direction is modulated by the oscillating light reflecting part 221a is emitted to the outside.

  In order to prevent a part of the light beam from being reflected or scattered by the substrate 10 and becoming stray light in the sealing member of the scanner 1 when the light beam passes through the upper sealing portion substrate 10, the getter film described above is used. It is desirable to provide a light absorption film (antireflection film) at 110. For example, GeN, TiN or the like can be used as the light absorption film. Among the getter films 110 described above, a film having a high light absorption effect (black type) can be selected. Further, the reflected light can be reduced by patterning the shape of the getter film 110 into a so-called moth-eye shape.

  A drive coil 62 as drive means is arranged at a position corresponding to the magnetic body (permanent magnet (hard magnetic body) or soft magnetic body) of the vibration structure on the outer surface of the lower sealing substrate 11 which is a sealing member. Has been. The vibration structure does not have a moving coil, and since the drive coil 62 is arranged outside the sealing member, there is no electric wiring penetrating the inside and outside of the sealing member, and a configuration that is convenient for maintaining a sealed body. It has become.

  Next, the configuration of each unit will be described.

  As shown in FIG. 2, the actuator 1 includes a vibration system forming substrate 2 that includes a first vibration system 21 and a second vibration system 22. Further, as shown in FIG. 3, the vibration system forming substrate 2 is sealed by bonding the upper sealing substrate 10 and the lower sealing substrate 11 through the bonding layer 4. The bonding layer 4 is an anodic bonding portion or an adhesive layer that has already been described.

  As shown in FIG. 2, the vibration system forming substrate 2 includes a frame-shaped support portion 23, a first vibration system 21 supported by the support portion 23, and a second support supported by the first vibration system 21. And a vibration system 22. 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.

That is, the vibration system forming substrate 2 includes the movable plate 221, the pair of second shaft members 222 and 223, the drive member 211, the pair of second shaft members 212 and 213, and the support portion 23. It is configured.
The drive member 211 has an annular shape in a plan view of FIG. 2 (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. And the permanent magnet 61 as a magnetic body mentioned later is provided in the lower surface of this drive member 211. As shown in FIG. 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. Each of the first shaft members 212 and 213 connects the drive member 211 and the support portion 23 so that the drive member 211 can be rotated with respect to the support portion 23. The 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 the shaft (hereinafter referred to as “rotation center axis X”). And is configured to rotate.

  The movable plate 221 formed inside the drive member 211 has a circular shape in plan view. However, the shape of the movable plate 221 is not particularly limited. In addition, a light reflecting portion 221 a having light reflectivity is formed on the upper surface of the movable plate 221. Such a 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. Each of the second shaft members 222 and 223 connects the movable plate 221 and the drive member 211 so that the movable plate 221 can be rotated 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. 2, 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, each of the center of the drive member 211 and the center of the movable plate 221 is located on the intersection of the rotation center axis X and the rotation center axis Y in the plan view of FIG.

  As described above, the vibration system forming substrate 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, and a first member. The shaft members 212 and 213 and the support portion 23 are 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 vibration system forming substrate 2 includes a movable plate 221, second shaft members 222 and 223, a drive member 211, first shaft members 212 and 213, and a substrate having a laminated structure such as an SOI substrate. The support part 23 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. 3, the vibration system forming substrate 2 as described above is bonded to the world sealing substrate 10 and the lower sealing substrate 11 through the bonding layer 4. The sealing substrates 10 and 11 are made of, for example, glass or silicon as a main material. The outer peripheral frame body portion of the lower sealing substrate 11 has substantially the same shape as the support portion 23 in plan view of the movable plate 221 (that is, has a frame shape). However, the shapes of the upper and lower sealing substrates 10 and 11 are not particularly limited as long as the vibration system forming substrate 2 can be supported. Alternatively, the entire vibration system forming substrate 2 may be accommodated in the recess of the lower sealing substrate 11 and the upper sealing substrate 10 may be configured as a flat (no recess) lid.

The bonding layer 4 formed between the lower sealing substrate 11 and the vibration system forming substrate 2 may be composed of, for example, glass, silicon, or SiO ₂ as a main material in addition to the adhesive made of the resin described above. it can. However, such a bonding layer 4 may be omitted (not required). That is, it is only necessary that the vibration system forming substrate 2 is fixed and sealed in the sealing member.

  A drive coil 62 for applying a magnetic field to the permanent magnet 61 is provided on the lower surface of the lower sealing substrate 11. As shown in FIG. 3, the coil 62 is electrically connected to the voltage applying means 63. The permanent magnet 61, the coil 62, and the voltage applying means 63 constitute the driving means 6.

  As shown in FIG. 3, the permanent magnet 61 has a longitudinal shape. The permanent magnet 61 is bonded to the lower surface of the driving member 211 via the adhesive layers 81 and 82. That is, the permanent magnet 61 is provided on the surface of the movable plate 221 opposite to the light reflecting portion 221a. Thereby, it can prevent that the optical scanning in the light reflection part 221a is obstructed by the permanent magnet 61. FIG.

Further, the permanent magnet 61 passes through the intersection of the rotation center axis X and the rotation center axis Y (hereinafter, this intersection point is also referred to as “intersection point G”) in the plan view of FIG. And a line segment inclined with respect to each of the rotation center axes Y (hereinafter, this line segment is also referred to as “line segment J”).
Such a permanent magnet 61 has an S pole on one side and an N pole on the other side with respect to the intersection G in the longitudinal direction. That is, the line segment connecting the S pole and the N pole of the permanent magnet 61 (that is, the line segment J) is inclined with respect to the rotation center axis X and the rotation center axis Y. In FIG. 3, for convenience of explanation, the permanent magnet 61 is illustrated with the left side in the longitudinal direction as the S pole and the right side as the N pole.

  In the plan view of FIG. 2, the inclination angle θ of the line segment J with respect to the rotation center axis X is preferably 30 to 60 degrees, more preferably 40 to 50 degrees, and approximately 45 degrees. Is more preferable. By providing the permanent magnet 61 in this manner, the movable plate 221 can be rotated around the rotation center axis X and the rotation center axis Y very smoothly. On the other hand, if the tilt angle θ is less than the lower limit value, the movable plate 221 may not be smoothly rotated around the X axis depending on the strength of the voltage applied to the coil 62 or the like. . On the other hand, when the inclination angle θ exceeds the upper limit value, the movable plate 221 may not be smoothly rotated around the Y axis depending on the strength of the voltage applied to the coil 62 or the like.

In the present embodiment, the line segment J is inclined 45 degrees with respect to each of the rotation center axis X and the rotation center axis Y.
Further, as shown in FIG. 3, a concave portion 611 is formed on the surface (that is, the upper surface) of the permanent magnet 61 on the movable plate 221 side. The recess 611 is an escape portion for preventing contact between the permanent magnet 61 and the movable plate 221. By forming such a recess (escape portion) 611, the movable plate 221 can be smoothly rotated about the rotation center axis Y. In addition, since the escape portion is the recess 611, the contact between the permanent magnet 61 and the movable plate 221 can be prevented very easily. However, the escape portion is not particularly limited as long as the contact between the movable plate 221 and the permanent magnet 61 can be prevented. For example, the escape portion is orthogonal to the rotation center axis X and the rotation center axis Y. It may be a through hole formed in a direction. For example, when the adhesive layers 81 and 82 have such a thickness that the contact between the movable plate 221 and the permanent magnet 61 can be prevented, such a recess 611 may be omitted.

Such a permanent magnet 61 is not particularly limited, and for example, a magnet obtained by magnetizing a hard magnetic material such as a neodymium magnet, a ferrite magnet, a samarium cobalt magnet, an alnico magnet, or a bond magnet can be suitably used.
In addition, it is good also as the permanent magnet 61 by providing the hard magnetic body (namely, permanent magnet) already magnetized in the lower surface of the drive member 211, or after providing a hard magnetic body in the drive member 211, the hard magnetic body is provided. May be used as the permanent magnet 61.

  The adhesive layers 81 and 82 for joining the permanent magnet 61 and the drive member 211 are made of, for example, an adhesive. Thereby, the drive member 211 and the permanent magnet 61 can be firmly bonded (joined). However, as long as the permanent magnet 61 can be provided on the lower surface of the drive member 211, the material constituting the adhesive layers 81 and 82 is not particularly limited. In addition, the bonding layers 81 and 82 may be omitted for the method of joining the permanent magnet 61 and the drive member 211.

  A drive coil 62 is provided directly below the permanent magnet 61 and outside the lower sealing substrate 11. That is, the coil 62 is provided so as to face the lower surfaces of the movable plate 221 and the drive member 211. The coil 62 may be wound around a magnetic core, for example. Thus, by providing the coil 62 directly below the permanent magnet 61, the coil 62, the permanent magnet 61, and the movable plate 221 and the driving member 211 are maintained in a reduced-pressure atmosphere (preferably in a high vacuum state). The distance between the movable plate 221 and the driving member 211 can be moved at high speed by reducing the air resistance. Further, the magnetic field generated from the coil 62 can be efficiently applied to the permanent magnet 61. That is, high-frequency operation, power saving, and downsizing of the actuator 1 can be achieved.

  Such a coil 62 is electrically connected to the voltage applying means 63. When a voltage is applied to the coil 62 by the voltage applying means 63, a magnetic field having an axial magnetic flux perpendicular to the rotation center axis X and the rotation center axis Y is generated from the coil 62.

  As shown in FIG. 4, the voltage applying unit 63 includes a first voltage generating unit 631 that generates a first voltage V <b> 1 for rotating the movable plate 221 around the rotation center axis X, and a movable plate 221. A second voltage generator 632 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 62. And a voltage superimposing unit 633 applied to the.

As shown in FIG. 5A, the first voltage generator 631 generates a first voltage V1 (vertical scanning voltage) that periodically changes at a period T1.
The first voltage V1 has a waveform like a sawtooth wave. Therefore, the actuator 1 can effectively perform vertical scanning (sub-scanning) of light. Note that the waveform of the first voltage V1 is not limited to this. 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 V <b> 1 is different from the torsional resonance frequency of the first vibration system 21 configured by the driving member 211 and the pair of first shaft members 212 and 213. Has been adjusted.
On the other hand, as shown in FIG. 5B, the second voltage generator 632 generates a second voltage V2 (horizontal scanning voltage) that periodically changes at a period T2 different from the period T1. .

The second voltage V2 has a waveform like a sine wave. Therefore, the actuator 1 can perform main scanning of light effectively. Note that the waveform of the second voltage V2 is not limited to this.
The frequency of the second voltage V2 is preferably higher than the frequency of the first voltage V1. That is, the period T2 is preferably shorter than the period T1. As a result, the movable plate 221 is rotated around the rotation center axis X at the frequency of the second voltage V2 while rotating the movable plate 221 around the rotation center axis X at a frequency of the second voltage V2. Can be moved.

  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. Thus, 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 as described above, the movable plate 221 has a frequency suitable for drawing on the display. The rotation center axis X and the rotation center axis Y can be rotated around the respective axes. However, if the movable plate 221 can be rotated around each of the rotation center axis X and the rotation center axis Y, the frequency of the first voltage V1, the frequency of the second voltage V2, and the first voltage A combination of the frequency of V1 and the frequency of the second voltage V2 is not particularly limited.

  In the present embodiment, the frequency of the second voltage V2 is adjusted to be equal to the torsional resonance frequency of the second vibration system 22 configured by the movable plate 221 and the pair of second shaft members 222 and 223. Has been. 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 631 and the second voltage generation unit 632 are connected to the control unit 7 and driven based on a signal from the control unit 7. A voltage superimposing unit 633 is connected to the first voltage generating unit 631 and the second voltage generating unit 632 as described above.
The voltage superimposing unit 633 includes an adder 633 a for applying a voltage to the coil 62. The adder 633a receives the first voltage V1 from the first voltage generator 631, and also receives the second voltage V2 from the second voltage generator 632, and superimposes these voltages and applies them to the coil 62. It has become.

  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 18 kHz).

For example, the first voltage V 1 as shown in FIG. 5A and the voltage V 2 as shown in FIG. 5B are superimposed by the voltage superimposing unit 633, and the superimposed voltage is applied to the coil 62.
Then, the first voltage V1 tries to attract the vicinity of the adhesive layer 81 of the driving member 211 to the coil 62, and the magnetic field that attempts to separate the vicinity of the adhesive layer 82 of the driving member 211 from the coil 62. Magnetic field A1 ”) and a magnetic field that tries to separate the vicinity of the adhesive layer 81 of the drive member 211 from the coil 62 and attract the coil 62 near the adhesive layer 82 of the drive member 211 (this magnetic field is referred to as“ magnetic field A2 ”). ”) And the display alternately.

  Here, in the plan view of FIG. 2, the adhesive layer 81 is located on one side and the adhesive layer 82 is located on the other side with respect to the rotation center axis X of the drive member 211. In other words, the pair of first adhesive layers 81 and 82 are provided on the drive member 211 so as to sandwich the rotation center axis X in the plan view of FIG. Therefore, by alternately switching the magnetic field A1 and the magnetic field A2 as described above, the driving member 211 together with the movable plate 221 has the frequency of the first voltage V1 while twisting and deforming the first shaft members 212 and 213. To rotate around the rotation center axis X.

  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, the second voltage V2 tries to attract the vicinity of the adhesive layer 81 of the driving member 211 to the coil 62, and to magnetically separate the vicinity of the adhesive layer 82 of the driving member 211 from the coil 62. Magnetic field B1 ") and a magnetic field (this magnetic field is referred to as" magnetic field B2 ") that attempts to separate the vicinity of the adhesive layer 81 of the drive member 211 from the coil 62 and attract the vicinity of the adhesive layer 82 of the drive member 211 to the coil 62. ”) And the display alternately.

Here, in the plan view of FIG. 2, the adhesive layer 81 is located on one side and the adhesive layer 82 is located on the other side with respect to the rotation center axis Y of the drive member 211. In other words, the pair of first adhesive layers 81 and 82 are provided on the drive member 211 so as to sandwich the rotation center axis Y in the plan view of FIG. Therefore, the magnetic plate B1 and the magnetic field B2 are alternately switched, so that the movable plate 221 rotates at the frequency (15 kHz) of the second voltage V2 while the second shaft members 222 and 223 are torsionally deformed. Rotate around.
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. In addition, by driving under reduced pressure by sealing under reduced pressure, a large Q value can be obtained as compared with driving under the atmosphere. In this configuration, since the coil is not included in the sealed under reduced pressure, the volume to be decompressed is small, and it is not necessary to draw the coil wiring to the outside. Thereby, a decompression environment can be maintained easily. For example, the pressure can be reduced to about 0.01 Pa. At this time, a Q value that is several tens to several hundred times as large as the Q value under the atmosphere is obtained. The magnitude of the Q value depends on the size of the movable plate, the driving frequency, and the amplitude. In addition, by placing the coil outside the sealing material, the gap between the permanent magnet and the coil is increased by the thickness of the sealing material, and there is a concern that the driving efficiency may be reduced. However, in this configuration, the gap is increased. Therefore, the increase in drive efficiency by increasing the Q value due to the pressure reduction effect kept stably can be sufficiently effective against the decrease in drive efficiency.

  As described above, in the actuator 1, the movable plate 221 is moved around the rotation center axis X by applying a voltage obtained by superimposing the first voltage V 1 and the second voltage V 2 to the coil 62. While rotating at the frequency of the voltage V1, it is possible to rotate around the rotation center axis Y at the frequency of the second voltage V2. As a result, the movable plate 221 can be rotated around the rotation center axis X and the rotation center axis Y very smoothly while reducing costs and downsizing.

In particular, since the number of permanent magnets and coils serving as driving sources can be reduced, a simple and compact configuration can be achieved.
In addition, by appropriately changing the first voltage V1 and the second voltage V2, desired vibration characteristics can be obtained without changing the design of the vibration system forming substrate 2 and the permanent magnet 61.
In the actuator 1, a permanent magnet 61 is provided on the drive member 211, and a coil 62 is provided on the outer surface of the lower sealing substrate 11 so as to face the permanent magnet 61. That is, the coil 62 that is a heating element is not provided on the first vibration system 21. Moreover, the coil 62 which is a heat generating body is not provided in the closed space. Therefore, thermal expansion of the vibration system forming substrate 2 due to heat generated from the coil 62 by energization and heat generation inside the closed space can be suppressed. As a result, the actuator 1 can exhibit desired vibration characteristics even when used continuously for a long time.

(Example 2)
6 and 7 show another embodiment of the present application. In the same figure, parts corresponding to those in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof will be omitted.

  In this embodiment, instead of the rod-shaped permanent magnet 61 provided on the drive member 211, two magnetic bodies 61a and 61b are arranged at the positions of the two magnetic poles of the permanent magnet 61, respectively. The magnetic bodies 61a and 61b are permanent magnets (hard magnetic bodies) corresponding to the S pole and N pole of the permanent magnet 61, respectively. Moreover, soft magnetic materials, such as iron, a silicon rope, and a ferrite, may be sufficient. Drive coils 62a and 62b are provided corresponding to these two magnetic bodies 61a and 61b, respectively. Each of the drive coils 62a and 62b is supplied with a current that generates a magnetic field having a complementary polarity by the voltage applying means. The drive coil 62a is disposed on the lower surface of the lower sealing substrate 11 directly below the magnetic body 61a, and the drive coil 62b is disposed on the lower surface of the lower sealing substrate 11 directly below the magnetic body 61b. Even with such a configuration, the movable plate 221 is rotated at high speeds around the rotation center axis X and the rotation center axis Y in a reduced pressure atmosphere while reducing the size of the actuator 1. be able to.

  Also in this embodiment, the aforementioned getter film 110 is formed on the inner surface of the upper sealing substrate 10 to improve the degree of vacuum of the closed space formed between the upper and lower sealing substrates 10 and 11. The getter film 110 only needs to be present in the closed space, and the arrangement location thereof is not limited to the inner surface of the upper sealing substrate 10. The getter film 110 may also serve as an antireflection light absorption film.

  As described above, according to the embodiment of the present invention, since the movable part of the actuator is arranged in the closed space by the sealing member, there is no entry of dust or the like inside, and the light reflecting part (mirror) is contaminated. Few. In addition, since the movable part is not exposed to an external gas, it is not easily affected by changes over time such as oxidation, so the life is extended. In addition, since the drive coil is disposed in the vicinity of the magnetic body of the movable part of the sealing member, there is no electrical wiring penetrating the inside and outside of the sealing member, and it is easy to maintain airtightness. And since the air resistance when the movable part operates is reduced by making the closed space in the sealing member into a decompression-like body (more preferably in a vacuum state), the movable part vibrates (rotates) at a higher frequency. Can be made. In addition, since the air resistance when the movable part operates is reduced, the movable part can be driven with low power consumption. Since the magnetic body (magnet) of the movable part and the drive coil can be arranged close to each other, the entire actuator can be made small even if a sealing member is provided.

  Since the actuator 1 as described above includes the light reflecting portion 221a, for example, it is suitable for an optical scanner provided in an image forming apparatus such as a laser printer, a barcode reader, a scanning confocal laser microscope, or an imaging display. Can be applied. 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. 8, 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 plateau 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.

  Further, in the above-described embodiment, the one using a permanent magnet having a longitudinal shape or the one having a circular shape has been described. However, in the plan view of the movable plate, the line segment connecting both poles is the axis of each of the X axis and the Y axis. If it is provided so as to be inclined with respect to the shape, the shape is not particularly limited. For example, the planar shape of the movable plate may be elliptical or square. Further, for example, a pair of yokes may be provided so that the permanent magnet is sandwiched in the direction of the line segment connecting both poles, and the magnetic flux may be guided by this yoke.

It is a top view which shows the example of the actuator of this invention. It is a top view which shows a vibration mechanism in the state which removed the upper side sealing substrate of the actuator of this invention. It is sectional drawing of the actuator shown by FIG. It is a block diagram which shows the voltage application means of the drive means with which the actuator shown in FIG. 2 is provided. FIG. 5 is a diagram illustrating an example of voltages generated in a first voltage generation unit and a second voltage generation unit illustrated in FIG. 4. It is a top view which shows the other Example of the actuator of this invention. It is sectional drawing which shows the other Example of the actuator of this invention. 1 is a schematic view showing an image forming apparatus of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Actuator, 2 Vibration system formation board | substrate, 10 Upper side sealing substrate, 11 Lower side sealing board | substrate, 110 Getter film | membrane, 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, 61a, 61b permanent magnet (magnetic material) 611 Concave part 62 Drive coil, 63 Voltage application means, 631 1st voltage generation part, 632 2nd voltage generation part, 633 Voltage superposition part, 633a Adder, 7 Control part, 81, 82 Adhesive layer, 9 Image forming apparatus (Projector), 91 light source device, 911 red light source device, 912 blue light source device, 913 green light source device, Second dichroic mirror, M fixed mirror, S screen X, Y rotation center axis

Claims (9)

A vibration system forming substrate on which a vibration structure that supports the movable plate so as to be rotatable about the first and second axes is formed;
Two magnetic poles are arranged with the movable plate interposed therebetween, and the vibration structure is provided so that a line segment connecting the two magnetic poles is inclined with respect to each of the first and second axes. Magnetic material,
A sealing member that operably surrounds the movable plate, the vibration structure, and the magnetic body to form a closed space, and maintains the closed space in an atmosphere reduced to an atmospheric pressure or lower; and
An actuator provided with a drive coil provided at a position facing the magnetic body on the outer surface of the sealing member.   The actuator according to claim 1, further comprising a getter film that absorbs gas in the closed space inside the sealing member.   The movable plate is provided with a reflective film, and a transparent window portion through which incident light to the reflective film and reflected light from the reflective film pass is formed in a part of the sealing member. The actuator according to claim 2, wherein the getter film is disposed as a light absorption film at least around the window.   The actuator according to claim 1 or 2, wherein the sealing member is formed by joining an upper sealing member and a lower sealing member, at least one of which has a recess.   The actuator according to claim 4, wherein the upper sealing member is glass, the vibration system forming substrate is silicon, and the lower sealing member is glass. The vibrating structure is
A frame-shaped drive member;
A first vibration system composed of a pair of first shaft members that support both of the drive members so that the drive members can rotate about the X axis;
The movable plate provided inside the drive member;
A second pair of second shaft members configured to both-support the movable plate on the drive member so that the movable plate can be rotated about a Y axis orthogonal to the X axis. The actuator according to claim 1, comprising a vibration system. Furthermore, a voltage applying means for applying a driving voltage to the coil is provided,
The voltage applying means includes a voltage generating unit that generates a first alternating voltage and a second alternating voltage having different frequencies, and a voltage superimposing unit that superimposes the first voltage and the second voltage. And applying the voltage superimposed by the voltage superimposing unit to the coil to rotate the movable plate around the X axis at the frequency of the first voltage, and at the frequency of the second voltage. The actuator according to claim 1, wherein the actuator is configured to rotate around the Y axis.   An optical scanner that generates two-dimensional scanning light using the actuator according to claim 1.   An image forming apparatus that forms an image with two-dimensional scanning light using the actuator according to claim 1.

Images