JP5233221B2 - Actuator, optical scanner, and image forming apparatus - Google Patents

Description

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

For example, an optical scanner for performing drawing by optical scanning with a laser printer, a display, or the like is known that uses an actuator having a structure constituting a torsional vibrator (see, for example, Patent Document 1). .
For example, the actuator disclosed in Patent Document 1 has a structure in which a mirror portion having a mirror surface is supported by a pair of torsion bars. Then, the mirror unit is rotated with torsional deformation of each torsion bar, and the light reflected by the light reflecting unit is scanned. Thereby, drawing can be performed by optical scanning.
In the actuator according to Patent Document 1, a strain gauge (piezoresistive element) is provided on the torsion bar. And based on the variation | change_quantity of the resistance value of a strain gauge, the rotation angle of a mirror part is detected. By rotating the mirror unit based on such a detection result, the behavior of the mirror unit can be made desired.

However, the optical scanner according to Patent Document 1 has the following problems (1) to (3).
(1) Since the wiring for the strain gauge is provided on the torsion bar, if the width of the torsion bar is small, it is difficult to route the wiring and it is difficult to reduce the size of the actuator.

(2) If the strain gauge is made small in order to secure a space for routing the wiring, alignment and electrical contact between the strain gauge and the wiring become difficult. Even if the width of the torsion bar is increased in order to secure a space for routing the wiring, the output of the strain gauge with respect to the unit torsion amount of the torsion bar decreases, resulting in a decrease in detection accuracy. .
(3) Further, a large stress is generated in the wiring due to the torsional deformation of the torsion bar. Therefore, disconnection of the wiring is likely to occur, and the reliability of the actuator is lowered.

JP-A-5-119280

  It is an object of the present invention to provide an actuator, a light, and an optical device that have excellent piezoresistive elements for detecting the behavior of a movable plate, have excellent detection accuracy while achieving downsizing, and excellent reliability. To provide a scanner and an image forming apparatus.

Such an object is achieved by the present invention described below.
An actuator according to the present invention includes a vibrating part including a movable plate and a pair of shaft members that support the movable plate;
A support part for supporting the vibration part;
A piezoresistive element provided in the vibrating section for detecting the behavior of the movable plate;
A plurality of electrodes provided on the support;
A resin layer formed such that a part is bonded to the vibration part and the support part, and the remaining part is separated from each shaft member;
Is deposited on the resin layer, and a wiring for electrically connecting the said piezoresistive elements each electrode,
Drive means for rotating the movable plate with torsional deformation of each shaft member;
The wiring is disposed such that at least a part thereof is separated from each shaft member ,
The resin layer is provided such that a surface of the resin layer on the wiring side is the vibrating portion side, and each of the wirings is bonded to the piezoresistive element via a conductive bump,
The resin layer collectively supports the plurality of wires on the shaft member side with respect to the support portion,
The resin layer has a portion extending to the side opposite to the shaft member with respect to the support portion, and the plurality of electrodes are bonded to the portion.

Thereby, even when the width of each shaft member is small, the wiring can be easily routed. Further, since a space for routing the wiring on both sides of the piezoresistive element in the width direction of each shaft member is not required, the degree of freedom of layout of the piezoresistive element is high. Therefore, it is possible to improve the detection accuracy of the piezoresistive element while reducing the size of the actuator.
Furthermore, the stress generated in the wiring due to the torsional deformation of each shaft member can be reduced. Therefore, the disconnection of the wiring hardly occurs, and the reliability of the actuator can be improved.
Moreover, since the resin layer reinforces the wiring, the disconnection of the wiring can be prevented. Further, the resin layer and the wiring can be made flexible, and the influence of the wiring on each shaft member can be reduced.
Furthermore, a part of the resin layer is joined to the vibration part and the support part, and the remaining part is formed so as to be separated from each shaft member, thereby reducing the influence of wiring on each shaft member, The reinforcement of the wiring by the resin layer can be strengthened.
In addition, the resin layer is provided so that the surface on the wiring side is the vibrating portion side, and the wiring is joined to the piezoresistive element via a conductive bump, so that the wiring is previously placed on the resin layer. Wiring can be easily installed just by affixing what was formed to a vibration part and a support part.
Furthermore, since the resin layer has a portion extending to the opposite side of the shaft member with respect to the support portion, and a plurality of electrodes are joined to the portion, it is easy to connect each electrode from the lower surface side of the resin layer. Can be accessed.

In the actuator according to the aspect of the invention, the piezoresistive element may be provided on at least one of the pair of shaft members, and the wiring may be provided along the at least one shaft member. preferable.
Thereby, the piezoresistive element can detect the torsional deformation amount of the shaft member, and can detect the behavior of the movable plate based on the detection result. In such a case, the influence of the wiring on the shaft member can be reduced by providing the wiring along the shaft member.

In the actuator according to the aspect of the invention, it is preferable that the piezoresistive element includes a piezoresistive region provided on the shaft member and at least one pair of terminals provided in the piezoresistive region apart from each other.
A piezoresistive element having such a piezoresistive region can be formed by doping a part of a shaft member with impurities, and is suitable for use in a narrow shaft member. Therefore, when such a piezoresistive element is used, the effect of the present invention as described above becomes remarkable.

In the actuator according to the aspect of the invention, the at least one pair of terminals are separated from each other in a direction orthogonal to the axis of the shaft member and the pair of first terminals arranged in parallel to each other in the axial direction of the shaft member. And a pair of second terminals arranged side by side.
Thus, the piezoresistive element having two pairs of terminals has excellent detection accuracy. In addition, such a piezoresistive element has a large number of terminals and accordingly a large number of wirings. However, by applying the present invention, the effect of the present invention as described above becomes extremely remarkable.

In the actuator according to the aspect of the invention, it is preferable that the piezoresistive element is provided on each of the shaft members, and the wiring is provided so that influences on the pair of shaft members are equal to each other.
Accordingly, it is possible to improve the detection accuracy of the piezoresistive element while improving the vibration characteristics of the vibration part.

In the actuator according to the aspect of the invention, it is preferable that the piezoresistive element is provided at an end portion of the shaft member on the support portion side.
Thereby, the length of wiring can be shortened and the influence of wiring with respect to each shaft member can be decreased.
In the actuator of the present invention, it is preferable that the movable plate and the shaft members are integrally formed of silicon.
Thereby, the vibration characteristic of a vibration part can be made excellent. Further, it is possible to increase the detection accuracy of the piezoresistive element with respect to shear stress depending on the crystal direction of silicon.
In the actuator of the present invention, it is preferable that the wiring is made of metal.
Although metal generally has excellent electrical conductivity, metal fatigue is caused by repeated deformation. Therefore, when the wiring comprised with the metal is used, the effect by applying this invention becomes remarkable.

An optical scanner according to the present invention includes a movable portion provided with a light reflecting portion, and a vibrating portion including a pair of shaft members that support the movable plate,
A support part for supporting the vibration part;
A piezoresistive element provided in the vibrating section for detecting the behavior of the movable plate;
A plurality of electrodes provided on the support;
A resin layer formed such that a part is bonded to the vibration part and the support part, and the remaining part is separated from each shaft member;
Is deposited on the resin layer, and a wiring for electrically connecting the said piezoresistive elements each electrode,
Drive means for rotating the movable plate with torsional deformation of each shaft member;
Configured to scan the light reflected by the light reflecting portion;
The wiring is disposed such that at least a part thereof is separated from each shaft member ,
The resin layer is provided such that a surface of the resin layer on the wiring side is the vibrating portion side, and each of the wirings is bonded to the piezoresistive element via a conductive bump,
The resin layer collectively supports the plurality of wires on the shaft member side with respect to the support portion,
The resin layer has a portion extending to the side opposite to the shaft member with respect to the support portion, and the plurality of electrodes are bonded to the portion.
As a result, the optical scanner of the present invention has excellent detection accuracy and excellent reliability in a configuration having a piezoresistive element for detecting the behavior of the movable plate while achieving downsizing. it can.

An image forming apparatus according to the present invention includes a movable portion provided with a light reflecting portion, and a vibration portion including a pair of shaft members that support the movable plate,
A support part for supporting the vibration part;
A piezoresistive element provided in the vibrating section for detecting the behavior of the movable plate;
A plurality of electrodes provided on the support;
A resin layer formed such that a part is bonded to the vibration part and the support part, and the remaining part is separated from each shaft member;
Is deposited on the resin layer, and a wiring for electrically connecting the said piezoresistive elements each electrode,
Drive means for rotating the movable plate with torsional deformation of each shaft member;
The light reflected by the light reflecting portion is scanned to form an image,
The wiring is disposed such that at least a part thereof is separated from each shaft member ,
The resin layer is provided such that a surface of the resin layer on the wiring side is the vibrating portion side, and each of the wirings is bonded to the piezoresistive element via a conductive bump,
The resin layer collectively supports the plurality of wires on the shaft member side with respect to the support portion,
The resin layer has a portion extending to the side opposite to the shaft member with respect to the support portion, and the plurality of electrodes are bonded to the portion.
As a result, the image forming apparatus of the present invention can provide a high-quality image and exhibit excellent reliability.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an actuator of the invention will be described with reference to the accompanying drawings.
<First Embodiment>
FIG. 1 is a perspective view showing a first embodiment of the actuator of the present invention, FIG. 2 is a plan view of the actuator shown in FIG. 1, and FIG. 3 is a sectional view of the actuator shown in FIG. A sectional view taken along line AA in FIG. 2, (b) is a sectional view taken along line BB in FIG. 2, and FIG. 4 is a partially enlarged perspective view for explaining a coil provided in the actuator shown in FIG. FIG. 5 is a partially enlarged perspective view for explaining the piezoresistive element and its wiring provided in the actuator shown in FIG.

In the following, for convenience of explanation, the upper side in FIG. 3 is referred to as “upper” and the lower side is referred to as “lower”.
As shown in FIG. 1, the actuator 1 of this embodiment is an actuator that employs an electromagnetic drive system (more specifically, a moving coil system), and includes a base body 2 having a vibration system (vibrating part), and the base body. 2, a pair of magnets (permanent magnets) 41 and 42, and piezoresistive elements 51 and 52 for detecting the behavior of the vibration system of the base 2.

Hereinafter, each part which comprises the actuator 1 is demonstrated sequentially.
As shown in FIG. 1, the base 2 includes a movable plate 21, a pair of shaft members 22 and 23 that support the movable plate 21, and a support portion 24 that is formed in a frame shape so as to surround them. ing.
The movable plate 21 has a plate shape, and in the present embodiment, the planar view shape is a rectangle. A light reflecting portion 211 having light reflectivity is provided on the plate surface (upper surface) of the movable plate 21. Thereby, the actuator 1 can be applied to an optical device such as an optical scanner, an optical attenuator, or an optical switch.

As shown in FIGS. 3 and 4, a coil 212 is provided on the lower surface of the movable plate 21. The coil 212 is arranged in a magnetic field of a pair of magnets 41 and 42 described later, and can apply an electromagnetic force to the movable plate 21 by energization. Here, the coil 212 and the pair of magnets 41 and 42 constitute drive means for the movable plate 21 to rotate with the torsional deformation of the shaft members 22 and 23.
Since the coil 212 is provided on the surface of the movable plate 21 opposite to the light reflecting portion 211, the degree of freedom in designing the light reflecting portion 211 is not reduced.

  In the present embodiment, the coil 212 is formed in a spiral shape along the plate surface of the movable plate 21 as shown in FIG. Such a spiral coil 212 can generate a larger magnetic force than a coil formed in an annular shape, and has a simpler structure than a coil formed by laminating the movable plate 21 in the thickness direction. It is easy to manufacture. That is, the configuration of the coil 212 can be made relatively simple, and the magnetic force generated in the coil 212 can be increased while suppressing the drive voltage.

  In addition, one end of the wire constituting the coil 212 (end on the outer periphery side of the spiral) is located near the boundary portion between the movable plate 21 and the shaft member 23 and is electrically connected to the wiring 231. In addition, the other end (end on the center side of the spiral) of the wire constituting the coil 212 is located near the center of the plate surface of the movable plate 21, but via the wiring 214 configured by wire bonding, In the vicinity of the boundary between the movable plate 21 and the shaft member 22, it is electrically connected to the wiring 221.

The connection between the other end of the wire constituting the coil 212 (the end on the center side of the spiral) and the wiring 221 is not limited to wire bonding, and for example, a wiring pattern is formed on the vibrating portion via an insulating film. In addition to the film, the insulating film may be provided with a through electrode that conducts to the wiring pattern.
Here, the above-described wiring 214 is joined and fixed to the movable plate 21 at one end 213 near the other end of the wire constituting the coil 212 (the end on the spiral side), and the other end is the movable plate. It is joined and fixed to a first joining point 222 in the vicinity of the boundary between the shaft 21 and the shaft member 22.

  In addition, an insulating film is preferably interposed between the movable plate 21 (vibrating portion) and the coil 212. Thereby, the insulation between the coil 212 and the movable plate 21 is excellent, and the reliability can be improved. In this case, an insulating film may be formed on the outer periphery of the wire constituting the coil 212, or an insulating film may be formed on the entire lower surface of the movable plate 21. The constituent material of the insulating film is not particularly limited as long as it has insulating properties, and examples thereof include resins and metal oxides.

The constituent material of the coil 212 is not particularly limited as long as it has conductivity, but metals such as copper and aluminum are preferably used.
Such a movable plate 21 is supported (both supported) by a pair of shaft members 22 and 23.
Each of the pair of shaft members 22 and 23 can be elastically deformed, and connects the movable plate 21 and the support portion 24.

In addition, the pair of shaft members 22 and 23 are provided coaxially with each other, and the movable plate 21 is accompanied by torsional deformation of the shaft members 22 and 23 using these as rotation center axes (rotation shafts) X. The support part 24 can be rotated.
A piezoresistive element 51 is provided on the upper surface of the shaft member 22, and a piezoresistive element 52 is provided on the upper surface of the shaft member 23. More specifically, the piezoresistive element 51 is provided at the end of the shaft member 22 on the support portion 24 side (the side opposite to the movable plate 21), and the piezoresistive element 52 is provided on the support portion 24 side of the shaft member 23 ( It is provided at the end of the side opposite to the movable plate 21. Thereby, the length of the wiring groups 53 and 55 (wiring), which will be described later, can be shortened, and the influence of the wiring on the shaft members 22 and 23 can be reduced.

The piezoresistive element 51 is electrically connected to an electrode group 54 provided on the support portion 24 via a wiring group 53. The piezoresistive element 52 is electrically connected to an electrode group 56 provided on the support portion 24 through a wiring group 55.
The wiring group 53 and the wiring group 55 are provided so that the influence on the pair of shaft members 22 and 23 is equal to each other. More specifically, the thickness, length, and the like of each wiring of the wiring group 53 and the wiring group 55 are set so that the influence on the pair of shaft members 22 and 23 is equal to each other. Thereby, it is possible to improve the detection accuracy of the piezoresistive elements 51 and 52 while improving the vibration characteristics of the vibration system (vibration unit) of the base 2.

The electrode group 54 includes electrodes 541, 542, 543, and 544, and the electrode group 56 includes electrodes 561, 562, 563, and 564 so as to be symmetrical with respect to the center of the movable plate 21 in plan view. Is provided. More specifically, the electrodes 541, 542, 543, and 544 and the electrodes 561, 562, 563, and 564 have their respective shapes so as to be symmetric with respect to the center of the movable plate 21 in plan view. Size, arrangement, etc. are set. Thereby, the influence of the wiring group 53 on the shaft member 22 and the influence of the wiring group 55 on the shaft member 23 can be equalized relatively easily.
Here, the piezoresistive element 52 and its wiring group 55 will be described in more detail. Note that the piezoresistive element 51 and the wiring group 53 thereof are the same as the piezoresistive element 51 and the wiring group 55, and thus description thereof is omitted.

As shown in FIG. 5, the piezoresistive element 52 includes a piezoresistive region 521 provided on the shaft member 23 and a pair of first piezoresistors arranged side by side in the rotation central axis X direction on the piezoresistive region 521. Terminals (input electrodes) 522 and 523, and a pair of second terminals (output electrodes) 524 and 525 arranged in parallel to the rotation axis X on the piezoresistive region 521 Yes.
The piezoresistive region 521 is formed by doping (diffusion or ion implantation) an n-type or p-type impurity on the surface of the shaft member 23. More specifically, when the base 2 is formed by processing a p-type silicon single crystal substrate, the piezoresistive region 521 is formed by doping impurities such as phosphorus on the surface of the shaft member 23. N-type silicon single crystal (n-type resistance region). On the other hand, when the base 2 is formed by processing an n-type silicon single crystal substrate, the piezoresistive region 521 is formed by p-type silicon formed by doping the surface of the shaft member 23 with an impurity such as boron. It is a single crystal (p-type resistance region).

  When the base 2 is formed by processing a (001) plane p-type silicon single crystal substrate, it follows the <110> direction of the piezoresistive region 521 (that is, the rotation center axis X direction). Thus, the shaft member 23 extends. On the other hand, when the substrate 2 is formed by processing an (001) -plane n-type silicon single crystal substrate, the <100> direction or <010> direction of the piezoresistive region 521 (that is, the rotation center axis) The shaft member 23 extends along the (X direction).

When the shaft member 23 extends along such a crystal orientation, when a shear stress is generated in the piezoresistive region 521 due to torsional deformation of the shaft member 23, the rate of change in the specific resistance value of the piezoresistive region 521 is expressed as follows. Can be the largest.
A first terminal 522 is provided at one end (end on the movable plate 21 side) of the both ends in the rotation center axis X direction on the piezoresistive region 521, and the other end (movable plate 21). 1st terminal 523 is provided in the edge part on the opposite side. The first terminal 522 is connected to the above-described electrode 561 through the wiring 551, and the first terminal 523 is connected to the above-described electrode 563 through the wiring 553. Accordingly, a voltage can be applied between the pair of first terminals 522 and 523 through the electrodes 561 and 563 and the wirings 551 and 553.

In addition, a second terminal 524 is provided at one end (the left end in FIG. 5) of both ends in a direction perpendicular to the rotation center axis X on the piezoresistive region 521, and the other end. A second terminal 525 is provided (on the right end in FIG. 5). The second terminal 524 is connected to the above-described electrode 564 through a wiring 554, and the second terminal 525 is connected to the above-described electrode 562 through a wiring 552. Accordingly, the voltage value and specific resistance value between the pair of second terminals 524 and 525 can be detected via the electrodes 562 and 564 and the wirings 552 and 525.
In the piezoresistive element 52 configured in this manner, the electric field E is applied to the piezoresistive region 521 via the pair of first terminals 522 and 523, and the pair of second terminals 524 and 525. By detecting the voltage value of the piezoresistive region 521 through the specific resistance value, the specific resistance value of the piezoresistive region 521 can be detected.

  More specifically, an electric field E is generated on the piezoresistive region 521 by applying a voltage between the pair of first terminals 522 and 523. When a shear stress is generated in the piezoresistive region 521 under such an electric field E, the specific resistance value of the piezoresistive region 521 changes according to the degree of the shear stress, and a potential difference corresponding to the change changes. It occurs between a pair of second terminals 524, 525. This potential difference depends on the amount of torsional deformation of the shaft member 23 and the rotation angle of the movable plate 21. Therefore, the behavior of the movable plate 21 can be detected based on this potential difference.

  As described above, the wirings 551, 552, 553, and 554 (that is, the wiring group 55) that electrically connect the piezoresistive element 52 and the electrodes 561, 562, 563, and 564 correspond to the piezoresistive element 52, respectively. It is longer than the distance between the electrodes 561, 562, 563 and 564. As a result, the wires 551, 552, 553, and 554 are disposed so as to be separated from the shaft member 23.

  As a result, even if the width of the shaft member 23 (length in a direction perpendicular to the rotation center axis X in plan view) is reduced, the wires 551, 552, 553, and 554 can be easily routed. Further, since no space is required for routing the wiring on both sides of the piezoresistive element 52 in the width direction of the shaft member 23, the degree of freedom of layout of the piezoresistive element is high. Therefore, it is possible to improve the detection accuracy by the piezoresistive element 52 while reducing the size of the actuator 1.

Further, the stress generated in each of the wirings 551, 552, 553, and 554 due to the torsional deformation of the shaft member 23 can be reduced. Therefore, disconnection of the wirings 551, 552, 553, and 554 hardly occurs, and the reliability of the actuator 1 can be improved.
Further, as described above, the piezoresistive element 52 having the piezoresistive region 521 can be formed by impurity doping as described above, and thus is suitable for use in the shaft member 23 having a narrow width. Therefore, when such a piezoresistive element 52 is used, the effects of the present invention as described above become significant.

Further, the piezoresistive element 52 having two pairs of terminals has excellent detection accuracy, but has a large number of terminals, and accordingly, a large number of wirings. However, by applying the present invention, it is not necessary to consider the space for wiring on the shaft member 23. Therefore, when the present invention is applied to such a piezoresistive element 52, the effect becomes very remarkable.
In particular, in the present embodiment, each of the wirings 551, 552, 553, and 554 is formed by wire bonding between the piezoresistive element 52 and the corresponding electrodes 561, 562, 563, and 564. That is, each of the wirings 551, 552, 553, and 554 is composed of a bonding wire. Thereby, formation of each wiring 551,552,553,554 can be made comparatively easy. In addition, since the wirings 551, 552, 553, and 554 formed of bonding wires are flexible and the spring constant thereof is extremely lower than the spring constant of the shaft member 23, the wirings 551, 552, and 553 with respect to the shaft member 23 are provided. 554 can make the influence of 554 extremely low.

Further, the wirings 551, 552, 553, and 554 are provided along the shaft member 23. Thereby, the influence of the wirings 551, 552, 553, and 554 on the shaft member 23 can be reduced.
In addition, the constituent material of each of the wirings 551, 552, 553, and 554 is not particularly limited as long as it has conductivity. However, when the wire bonding method is used as in this embodiment, a metal such as gold is used. Preferably used.

  Although metal generally has excellent electrical conductivity, metal fatigue is caused by repeated deformation. However, as described above, since the wires 551, 552, 553, and 554 are separated from the shaft member 23, the wires 551, 552, 553, and 554 are caused by the torsional deformation of the shaft member 23 and the rotation of the movable plate 21. Can be reduced, and disconnection of each of the wirings 551, 552, 553, and 554 can be prevented.

As shown in FIG. 3, terminals 241 and 242 are provided on the lower surface of the support portion 24 in the vicinity of the boundary between the shaft members 22 and 23.
The terminal 241 is electrically connected to the coil 212 and the wiring 221 described above, and the terminal 242 is electrically connected to the coil 212 and the wiring 231. As a result, the coil 212 can be energized via the wirings 221 and 231.

One end of the wiring 221 is joined and fixed to the movable plate 21 at a first junction point 222 near the boundary between the movable plate 21 and the shaft member 22, and the other end is a second junction point 223 on the terminal 241. Thus, it is joined and fixed to the support portion 24 (see FIG. 3).
Such a wiring 221 is formed by wire bonding the first junction point 222 and the second junction point 223.

Similarly, the wiring 231 has one end joined and fixed to the movable plate 21 at a first joining point 232 near the boundary between the movable plate 21 and the shaft member 23, and the other end connected to a second terminal on the terminal 242. It is joined and fixed to the support portion 24 at a joining point 233 (see FIG. 3).
Such a wiring 231 is formed by wire-bonding the first joint point 232 and the second joint point 233 as in the case of the wiring 221 described above.

Note that the wirings 221 and 231 are not limited to those formed by a wire bonding method.
Such wirings 221 and 231 are arranged so as to be separated from the shaft members 22 and 23. Thereby, the stress generated in the wirings 221 and 231 due to the torsional deformation of the shaft members 22 and 23 can be reduced, and the reliability of the actuator 1 can be improved.

In addition, since the wiring 221 is provided along the shaft member 22 and the wiring 231 is provided along the shaft member 23, stress generated in the wirings 221 and 231 due to the rotation of the movable plate 21 is reduced. The reliability of the actuator 1 can be improved.
Further, since the wirings 221 and 231 are formed by using wire bonding as described above, the reliability of the actuator 1 can be improved while the formation of the wirings 221 and 231 is relatively simple. it can.

Further, since the wires 221 and 231 have the pair of first joining points 222 and 232 as described above, the stress generated in the wires 221 and 231 due to the rotation of the movable plate 21 is reduced, and the actuator 1 Reliability can be improved.
In addition, since the wirings 221 and 231 have a pair of second joining points 223 and 233 as described above, the stress generated in the wiring due to the rotation of the movable plate 21 can be easily and reliably reduced. The reliability of the actuator 1 can be improved.

  In addition, each joint point 222, 223, 232, 233 is located on the rotation center axis X, and the distance between the first joint point 222 and the second joint point 223, and the first joint point 232 are arranged. And the second junction point 233 are equal. Therefore, the pair of first junction points 222 and 232 and the pair of second junction points 223 and 233 are provided so that the influence of the wirings 221 and 231 on the pair of shaft members 22 and 23 is equal to each other. ing. Thereby, the design of the actuator 1 can be simplified, and the vibration characteristics of the vibration part can be made excellent.

  Further, the wirings 221 and 231 are provided so that the influence on the pair of shaft members 22 and 23 is equal to each other. More specifically, the length of the wiring 221 and the length of the wiring 231 are set to be equal, the cross-sectional shape of the wiring 221 and the cross-sectional shape of the wiring 231 are set to be equal, and the cross-sectional area of the wiring 221 ( The thickness (thickness) and the cross-sectional area (thickness) of the wiring 231 are set equal. In other words, the wiring 221 and the wiring 231 are configured symmetrically. Thereby, the design of the actuator 1 can be simplified, and the vibration characteristics of the vibration part can be made excellent.

Further, the wiring 221 is longer than the distance between the first junction point 222 and the second junction point 223, and the wiring 231 is a distance between the first junction point 232 and the second junction point 233. Longer than. Thereby, the tension | tensile_strength which arises in each wiring 221 and 231 can be made small, and the stress which arises in wiring 221 and 231 can be reduced.
For each of these wirings 221, 231 as well as the coil 212 described above, between the shaft member 22 (vibrating part) and the wiring 221, or between the shaft member 23 (vibrating part) and the wiring 231, An insulating film is preferably interposed. Thereby, the insulation between the wirings 221 and 231 and the vibration part can be made excellent, and the reliability can be improved.

Further, the constituent material of each of the wirings 221 and 231 is not particularly limited as long as it has conductivity. However, when the wire bonding method is used as in this embodiment, a metal such as gold is preferably used. .
Such a movable plate 21 and the pair of shaft members 22 and 23 constitute a vibration system (vibration unit). That is, in the present embodiment, the vibration unit has one vibration system (that is, a one-degree-of-freedom vibration system) including the movable plate 21 and the pair of shaft members 22 and 23.
The base body 2 having such a vibration system is made of, for example, silicon as a main material, and a movable plate 21, a pair of shaft members 22, 23, and a support portion 24 are integrally formed. Thereby, the vibration characteristics and durability of the vibration part can be made excellent.

Moreover, such a vibration part is integrally formed by etching one substrate. Thereby, the vibration part integrally formed with silicon can be easily manufactured.
The average thickness of the substrate (that is, the thickness of the movable plate 21 and the shaft members 22 and 23) is not particularly limited, but is preferably 1 to 1500 μm, and more preferably 10 to 300 μm.

Further, the support portion 24 for supporting the vibration system (vibration portion) as described above has a frame shape so as to surround the outer periphery of the movable plate 21. The support 3 is joined to the lower surface of the support 24.
The support 3 is made of, for example, glass or silicon as a main material. The base body 2 and the support 3 are bonded by direct bonding or anodic bonding. The base 2 and the support 3 may be bonded via, for example, a bonding layer made of glass, silicon, or SiO ₂ as a main material, or may be bonded via an adhesive. Good.

The support 3 has a frame shape along the support portion 24 described above. In addition, the shape of the support body 3 is not limited to what was mentioned above.
In such a support 3, the space inside thereof prevents the contact with the support 3 when the vibration of the vibration system of the base 2, that is, when the movable plate 21 rotates (vibrates). Parts. By providing such an escape portion, the deflection angle (amplitude) of the movable plate 21 can be set larger while preventing the actuator 1 from being enlarged.
A pair of magnets 41 and 42 are joined and fixed to the side surface of the support 3.
The pair of magnets 41 and 42 are provided so as to face each other via the rotation center axis X of the movable plate 21 and to face the end surface of the movable plate 21 when not rotating. In this way, each magnet 41, 42 faces the coil 212.

Moreover, the magnet 41 is installed so that the movable plate 21 side is an S pole, and the magnet 42 is installed so that the movable plate 21 side is an N pole. Therefore, the pair of magnets 41, 42 generate a magnetic field in the vicinity of the movable plate 21 in a direction parallel to the plate surface of the movable plate 21 when not rotated and perpendicular to the rotation center axis X of the movable plate 21. generate.
Magnets 41 and 42 may be electromagnets instead of permanent magnets. Needless to say, the polarities of the magnets 41 and 42 are not limited to those shown in the drawing.

The actuator 1 having the above configuration operates as follows.
When a power supply circuit (not shown) applies an alternating voltage to the coil 212 via the wirings 221 and 231, the direction of the magnetic field generated in the coil 212 is switched alternately between the upward direction and the downward direction.
Therefore, the movable plate 21 arranged in the magnetic field of the pair of magnets 41 and 42 rotates (vibrates) with respect to the support portion 24 while the shaft members 22 and 23 are twisted and deformed.

  On the other hand, an electric field E is generated on the piezoresistive region 521 by applying a voltage between the pair of first terminals 522 and 523. Then, under such an electric field E, a potential difference generated between the pair of second terminals 524 and 525 is detected, and the behavior of the movable plate 21 such as the frequency, amplitude, and rotation angle is detected based on the potential difference. To do. A control means (not shown) controls the alternating voltage to the coil 212 based on the detected behavior so that the movable plate 21 has a desired behavior.

Here, the natural frequency ω ₁ of the vibration system composed of the movable plate 21 and the pair of shaft members 22 and 23 is the inertia moment J ₁ of the movable plate 21 and the spring constant k of the pair of shaft members 22 and 23. the ₁ and given by ^{_{ω 1 = (k 1 / J}} 1) 1/2. The frequency of the alternating voltage applied to the coil 212 may be the same as or different from the natural frequency ω1, but when it is the same as the natural frequency ω1, the actuator 1 can be operated efficiently.

  According to the actuator 1 configured as described above, the wiring group 53 that electrically connects the piezoresistive element 51 and the electrode group 54 is separated from the shaft member 22, and the piezoresistive element 52 and the electrode group are separated. Since the wiring group 55 that electrically connects to the shaft member 56 is disposed so as to be separated from the shaft member 23, each wiring of the wiring group 53 and the wiring group 55 can be connected even if the width of the shaft member 23 is reduced. It can be easily routed. In addition, since a space for routing the wiring on both sides of the piezoresistive element in the width direction of the shaft members 22 and 23 is not required, the degree of freedom of layout of each piezoresistive element is high. Therefore, it is possible to improve the detection accuracy by the piezoresistive elements 51 and 52 while downsizing the actuator 1.

Furthermore, the stress generated in each wiring of the wiring groups 53 and 55 due to the torsional deformation of the shaft members 22 and 23 can be reduced. Therefore, disconnection of each wiring of the wiring groups 53 and 55 hardly occurs, and the reliability of the actuator 1 can be improved.
In particular, in the present embodiment, since each wiring of the wiring groups 53 and 55 is composed of bonding wires, the formation of each wiring of the wiring groups 53 and 55 can be made relatively simple. Further, the influence of each wiring of the wiring groups 53 and 55 on the shaft members 22 and 23 can be reduced.

Second Embodiment
Next, a second embodiment of the actuator of the present invention will be described.
FIG. 6 is a plan view showing a second embodiment of the actuator of the present invention, and FIG. 7 is a partially enlarged perspective view for explaining a piezoresistive element and its wiring provided in the actuator shown in FIG.

In the following, the second embodiment will be described, but the description will focus on the differences from the first embodiment described above, and description of similar matters will be omitted.
The actuator of this embodiment is the same as that of the first embodiment described above except that the configuration of the wiring for the piezoresistive element is different. In the following description, only the configuration on one shaft member side will be described, but the same applies to the configuration on the other shaft member side.

As shown in FIG. 6, in the actuator 1A of this embodiment, the piezoresistive element 51 is electrically connected to the electrode group 54 via the wiring group 53A. The piezoresistive element 52 is electrically connected to the electrode group 56 through the wiring group 55A.
Each wiring group 53A, 55A has a thin film shape and is provided so that the influence on the pair of shaft members 22, 23 is equal to each other, like each wiring group 53, 55 of the first embodiment described above.

Here, the wiring group 55A will be described in more detail. Note that the wiring group 53A is the same as the wiring group 55A, and a description thereof will be omitted.
The wiring group 55A includes wirings 551A to 554A.
The wiring 551 </ b> A has a linear part along the shaft member 23 and an L-shaped part, and electrically connects the first terminal 522 of the piezoresistive element 52 and the electrode 561.

The wiring 552A has an L shape, and electrically connects the second terminal 525 of the piezoresistive element 52 and the electrode 562.
The wiring 553A has a linear shape, and electrically connects the first terminal 523 of the piezoresistive element 52 and the electrode 563.
The wiring 554 </ b> A has an L shape and electrically connects the second terminal 524 of the piezoresistive element 52 and the electrode 564.
In these wirings 551A to 554A, the wirings 551A, 552A, and 554A have portions separated from the shaft member 23, respectively. Thereby, the effect similar to the actuator 1 of 1st Embodiment mentioned above can be exhibited.

Although the wiring 553A is provided on the shaft member 23, the wiring 553A and the shaft member 23 may be joined, or may be contacted or non-contacted without being joined.
A method for forming each of the wirings 551A to 554A (thin film forming method) is not particularly limited, but includes dry plating methods such as vacuum deposition, sputtering (low temperature sputtering), ion plating, electrolytic plating, electroless plating, and the like. Wet plating, thermal spraying, metal foil bonding, or the like can be used.

  Further, these wirings 551A to 554A are integrally formed with the first terminals 522 and 523, the second terminals 524 and 525, and the electrodes 561 to 564 by using the thin film forming method as described above. . As a result, the manufacturing process of the actuator 1A can be simplified, the mechanical strength of the wiring group 55A can be made excellent, and the reliability of the actuator 1A can be improved.

Further, since the spring constant of each of the wirings 551A, 552A, 553A, and 554A configured as described above is extremely lower than the spring constant of the shaft member 23, the influence of the wirings 551A, 552A, 553A, and 554A on the shaft member 23 is affected. Can be very low.
As described above, the actuator 1A according to the second embodiment can exhibit the same effects as those of the actuator 1 of the first embodiment described above.

<Third Embodiment>
Next, a third embodiment of the actuator of the present invention will be described.
FIG. 8 is a partially enlarged perspective view for explaining a piezoresistive element and its wiring provided in the actuator according to the third embodiment of the present invention.
Hereinafter, the third embodiment will be described. However, the difference from the first and second embodiments described above will be mainly described, and the description of the same matters will be omitted.

The actuator of this embodiment is the same as that of 2nd Embodiment mentioned above except having provided wiring on the resin layer. In the following description, only the configuration on one shaft member side will be described, but the same applies to the configuration on the other shaft member side.
As shown in FIG. 8, in the actuator according to the present embodiment, wirings 551 </ b> A to 554 </ b> A and electrodes 561 to 564 are joined to the base 2 via a resin layer 57. That is, the wirings 551 </ b> A to 554 </ b> A and the electrodes 561 to 564 are bonded on the resin layer 57 bonded to the base 2.

Since the wirings 551A to 554A are thus formed on the resin layer 57, the resin layer 57 reinforces the wirings 551A to 554A, so that disconnection of the wirings 551A to 554A can be prevented. . Further, by selecting a flexible material or suppressing the thickness, the resin layer 57 and the wirings 551A to 554A can be made flexible, and the influence of the wirings 551A to 554A on the shaft member 23 can be reduced. it can.
More specifically, the resin layer 57 includes a rectangular main body portion 571 that supports the electrode group 56 and a plurality of extending portions 572 that extend from the main body portion 571 and individually support each wiring of the wiring group 56A. 575 and these are integrally formed.

The lower surface of the main body portion 571 is bonded to the support portion 24 of the base 2, and the electrodes 561 to 564 are bonded to the upper surface. Accordingly, the electrodes 561 to 564 are fixedly installed on the base 2.
The extending portion 572 is formed in an L shape along the wiring 551A, and supports the wiring 551A from the lower surface side. In addition, the extension part 572 has one end joined to the shaft member 23 and the other end joined to the support part 24.

The extending portion 573 is formed in an L shape along the wiring 552A, and supports the wiring 552A from the lower surface side. Further, one end of the extending portion 573 is joined to the shaft member 23, and the other end is joined to the support portion 24.
The extending portion 574 is linear along the wiring 553A (along the rotation center axis X), and supports the wiring 553A from the lower surface side. Further, the extending portion 574 is joined to the base 2 over almost the entire region in the longitudinal direction.

The extending portion 575 has an L shape along the wiring 554A, and supports the wiring 554A from the lower surface side. In addition, one end of the extending portion 575 is joined to the shaft member 23, and the other end is joined to the support portion 24.
As described above, the resin layer 57 is formed such that a part thereof is joined to the shaft member 23 (vibrating part) and the support part 24 and the remaining part is separated from the shaft member 23. The reinforcement of each wiring by the resin layer 57 can be strengthened while reducing the influence of the group 55A (particularly, the wirings 551A, 552A, and 554A).

The constituent material of the resin layer 57 is not particularly limited, and various thermoplastic resins and various thermosetting resins may be used alone or in combination of two or more (for example, as a laminate of two or more layers). However, it is preferable to use a thermosetting resin such as an epoxy resin, a phenol resin, a urea resin, a melamine resin, a polyester (unsaturated polyester) resin, a polyimide resin, a silicone resin, or a polyurethane resin, and in particular, a flexible printed circuit board (FPC). It is preferable to use a resin such as that used in (1). Thereby, the mechanical strength and thermal characteristics of the resin layer 57 can be made excellent.
Moreover, it does not specifically limit as a formation method of the resin layer 57, Various film-forming methods can be used.
Moreover, it does not specifically limit as a joining method of the resin layer 57 and the base | substrate 2, The thing by an adhesive agent etc. are mentioned.

<Fourth embodiment>
Next, a fourth embodiment of the actuator of the present invention will be described.
FIG. 9 is a partially enlarged perspective view for explaining a piezoresistive element and its wiring provided in an actuator according to a fourth embodiment of the present invention.
Hereinafter, although the fourth embodiment will be described, the description will focus on the differences from the first to third embodiments described above, and description of similar matters will be omitted.

The actuator of the present embodiment is the same as that of the third embodiment described above except that the shape and installation position of the resin layer, the shape of the wiring group, and the bonding form of the wiring and the piezoresistive element are different. In the following description, only the configuration on one shaft member side will be described, but the same applies to the configuration on the other shaft member side.
As shown in FIG. 9, in the actuator of this embodiment, the piezoresistive element 52 is joined to the electrode group 56 via the wiring group 55B. A resin layer 58 is bonded to the upper surfaces of the wiring group 55 </ b> B and the electrode group 56.

In other words, the wiring group 55B and the electrode group 56 are joined (supported) on the resin layer 58, and the resin layer 58 has a surface on the wiring group 55B and electrode group 56 side as the base 2 side (vibration part side). It is provided to do.
The wiring group 55B includes wirings 551B to 554B. The wirings 551B to 554A are joined to the piezoresistive element 52 via conductive bumps.

  For example, as illustrated in FIG. 9, the wiring 554 </ b> B is joined to the second terminal 524 through a bump 59 having a substantially hemispherical shape. Note that although not illustrated, with respect to the wirings 551B to 553B, like the wiring 554B, the wiring 551B is bonded to the first terminal 522 through a conductive bump, and the wiring 552B is conductive to the second terminal 525. The wiring 553B is bonded to the first terminal 523 via a conductive bump.

  Since each of the wirings 551B to 554B is joined to the piezoresistive element 52 through the conductive bumps in this way, the substrate 2 (the shaft member 23 (vibration) having the wirings 551B to 554B formed in advance on the resin layer 58 is formed. The wirings 561B to 564B can be easily installed simply by being attached to the part) and the support part 24). For example, molten metal material droplets may be applied to the first terminals 522, 523 and the second terminals 524, 525, respectively, before each droplet is completely solidified or cured (ie, molten or semi-solidified). In the state), the first terminals 522 and 523 and the second terminals 524 and 525 are brought into contact with the wiring group 55B, and then the respective droplets are cured or solidified to form bumps. Thereby, the structure including the wiring group 55 </ b> B and the resin layer 58 is attached to the base 2.

The constituent material of the bump is not particularly limited as long as it has conductivity, but a metal material is preferably used.
In the present embodiment, the resin layer 58 has a portion 581 extending from the edge of the support portion 24, and the electrode group 56 is provided on the portion 581. Thereby, the electrode group 56 can be easily accessed from the lower surface side of the resin layer 58.
Further, as the constituent material of the resin layer 58, the same material as the constituent material of the resin layer 57 in the third embodiment described above can be used.

The actuator according to the first to fourth embodiments as described above can be applied to, for example, an optical scanner, an optical switch, an optical attenuator, and the like.
When such an actuator is used as an optical scanner, the optical scanner (the optical scanner according to the present invention) scans the light reflected by the light reflecting unit 211. Such an optical scanner according to the present invention can exhibit excellent reliability.
Such an optical scanner can be suitably applied to an image forming apparatus such as a laser printer, an imaging display, a barcode reader, or a scanning confocal microscope.

Hereinafter, a specific example of an image forming apparatus provided with the optical scanner of the present invention will be described.
First, an example in which the present invention is applied to a printer that employs an electrophotographic system will be described.
FIG. 10 is a schematic cross-sectional view of an overall configuration showing an example of an image forming apparatus (printer) including the optical scanner of the present invention, and FIG. 11 is a schematic configuration of an exposure unit provided in the image forming apparatus shown in FIG. FIG.

  An image forming apparatus 110 (printer) shown in FIG. 10 records an image made of toner on a recording medium such as paper or an OHP sheet by a series of image forming processes including exposure, development, transfer, and fixing. As shown in FIG. 10, such an image forming apparatus 110 has a photoconductor 111 that rotates in the direction of the arrow shown in the drawing, and sequentially, along the rotation direction, a charging unit 112, an exposure unit 113, a developing unit 114, and a transfer unit. A unit 115 and a cleaning unit 116 are provided. In addition, in FIG. 10, the image forming apparatus 110 is provided with a paper feed tray 117 that accommodates a recording medium P such as paper at the bottom, and a fixing device 118 at the top.

In such an image forming apparatus 110, first, in response to a command from a host computer (not shown), the photosensitive member 111, the developing roller (not shown) provided in the developing unit 114, and the intermediate transfer belt 151 rotate. Start. The photosensitive member 111 is sequentially charged by the charging unit 112 while rotating.
The charged region of the photoconductor 111 reaches an exposure position as the photoconductor 111 rotates, and a latent image corresponding to image information of the first color, for example, yellow Y, is formed in the region by the exposure unit 113. .

  The latent image formed on the photoconductor 111 reaches the development position as the photoconductor 111 rotates, and is developed with yellow toner by the developing device 144 for yellow development. As a result, a yellow toner image is formed on the photoreceptor 111. At this time, in the developing unit 114, the developing device 144 selectively faces the photoconductor 111 at the developing position. This selection is performed by changing the respective positions while maintaining the relative positional relationship of the developing devices 141 to 144 by the rotation of the holding body 145 around the axis 146.

  The yellow toner image formed on the photoconductor 111 reaches a primary transfer position (that is, a portion where the photoconductor 111 and the primary transfer roller 152 face each other) as the photoconductor 111 rotates, and is intermediated by the primary transfer roller 152. Transfer (primary transfer) is performed on the transfer belt 151. At this time, a primary transfer voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the primary transfer roller 152. During this time, the secondary transfer roller 155 is separated from the intermediate transfer belt 151.

The same processing as described above is repeatedly executed for the second color, the third color, and the fourth color, so that the toner images of the respective colors corresponding to the respective image signals are transferred onto the intermediate transfer belt 151 in an overlapping manner. The As a result, a full color toner image is formed on the intermediate transfer belt 151.
On the other hand, the recording medium P is conveyed from the paper feed tray 117 to the secondary transfer position (that is, the portion where the secondary transfer roller 155 and the driving roller 154 face each other) by the paper feed roller 171 and the registration roller 172.

  The full color toner image formed on the intermediate transfer belt 151 reaches the secondary transfer position as the intermediate transfer belt 151 rotates, and is transferred (secondary transfer) to the recording medium P by the secondary transfer roller 155. At this time, the secondary transfer roller 155 is pressed against the intermediate transfer belt 151 and a secondary transfer voltage (secondary transfer bias) is applied. Further, the intermediate transfer belt 151 rotates while the driving roller 154 is rotated and the primary transfer roller 152 and the driven roller 153 are driven to rotate.

The full-color toner image transferred to the recording medium P is heated and pressurized by the fixing device 118 and fused to the recording medium P. Thereafter, in the case of single-sided printing, the recording medium P is discharged to the outside of the image forming apparatus 110 by the discharge roller pair 173.
On the other hand, after the primary transfer position has elapsed, the toner adhering to the surface of the photoconductor 111 is scraped off by the cleaning blade 161 of the cleaning unit 116 to prepare for charging to form the next latent image. The toner scraped off is collected by a residual toner collecting unit in the cleaning unit 116.

  In the case of double-sided printing, after the recording medium P fixed on one surface by the fixing device 118 is once sandwiched by the paper discharge roller pair 173, the paper discharge roller pair 173 is driven in reverse and the conveyance roller pair 174, 176 is driven, the recording medium P is turned upside down through the transport path 175 and returned to the secondary transfer position, and an image is formed on the other surface of the recording medium P by the same operation as described above.

The exposure unit 113 provided in such an image forming apparatus receives image information from a host computer such as a personal computer (not shown) and selectively applies a laser on the uniformly charged photoreceptor 111 in accordance with the image information. It is an apparatus that forms an electrostatic latent image by irradiation.
More specifically, as shown in FIG. 11, the exposure unit 113 includes an actuator 1 that is an optical scanner, a laser light source 131, a collimator lens 132, and an fθ lens 133.

In the exposure unit 113, the laser light L is irradiated from the laser light source 131 to the actuator 1 (light reflecting portion 211) via the collimator lens 132. Then, the laser beam L reflected by the light reflecting portion 211 is irradiated onto the photosensitive member 111 through the fθ lens.
At that time, the light (laser L) reflected by the light reflecting portion 211 by the drive of the actuator 1 (rotation about the rotation center axis X of the movable plate 21) scans in the axial direction of the photoconductor 111 (main scanning). Is done. On the other hand, the light (laser L) reflected by the light reflecting portion 211 due to the rotation of the photoconductor 111 is scanned (sub-scanned) in the circumferential direction of the photoconductor 111. Further, the intensity of the laser light L output from the laser light source 131 changes in accordance with image information received from a host computer (not shown).
In this way, the exposure unit 113 selectively exposes the surface of the photoconductor 111 to form an image (drawing).

Next, an example in which the present invention is applied to an imaging display (display device) will be described.
FIG. 12 is a schematic diagram illustrating an example of an image forming apparatus (imaging display) according to the present invention.
An image forming apparatus 119 shown in FIG. 12 includes an actuator 1 that is an optical scanner, light sources 191, 192, and 193 of three colors of R (red), G (green), and B (blue), and a cross dichroic prism (X prism). 194, a galvanometer mirror 195, a fixed mirror 196, and a screen 197.
In such an image forming apparatus 119, light of each color is irradiated from the light sources 191, 192, 193 to the actuator 1 (light reflecting portion 211) via the cross dichroic prism 194. At this time, the red light from the light source 191, the green light from the light source 192, and the blue light from the light source 193 are combined by the cross dichroic prism 194.

Then, the light (three colors of combined light) reflected by the light reflecting portion 211 is reflected by the galvanometer mirror 195, then by the fixed mirror 196, and irradiated on the screen 197.
At that time, the light reflected by the light reflecting portion 211 by the drive of the actuator 1 (rotation about the rotation center axis X of the movable plate 21) is scanned (main scan) in the horizontal direction of the screen 197. On the other hand, the light reflected by the light reflecting portion 211 due to the rotation of the galvano mirror 195 around the axis Y is scanned (sub-scanned) in the vertical direction of the screen 197. In addition, the intensity of light output from the light sources 191, 192, and 193 of each color changes according to image information received from a host computer (not shown).
In this way, the image forming apparatus 119 performs image formation (drawing) on the screen 197.

The actuator, the optical scanner, and the image forming apparatus of the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this. For example, in the actuator 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 piezoresistive element is provided in each of the shaft members 22 and 23, and at least a part of the wiring for each piezoresistive element is separated from the shaft member. The effect of the present invention can be exhibited even in a configuration in which only the wiring for the element is separated from the shaft member.

In the above-described embodiment, the description has been given of the vibration unit constituting the one-degree-of-freedom vibration system. However, the vibration unit may constitute the vibration system having the second degree of freedom or more. For example, when a vibration part comprises a 2 degree-of-freedom vibration system, a vibration part is comprised by providing a drive member (mass part) in the middle of each shaft member. Thereby, the vibration part constitutes a two-degree-of-freedom vibration system, and the deflection angle of the movable plate can be increased while reducing the drive voltage. In this case, the coil for electromagnetic drive is provided in one or a pair of drive members, and the junction of wiring is provided on the drive member.
In the above-described embodiment, the actuator using the moving coil method as the driving method has been described. However, the present invention is not limited to this, and the driving method of the actuator of the present invention (that is, the configuration of the driving means) is a moving coil method. Alternatively, a driving method other than an electromagnetic driving method such as a piezoelectric driving method or an electrostatic driving method may be used.

It is a perspective view which shows 1st Embodiment of the actuator of this invention. FIG. 2 is a plan view of the actuator shown in FIG. 1 is a cross-sectional view of the actuator shown in FIG. 1 ((a) is a cross-sectional view taken along the line AA in FIG. 2, and (b) is a cross-sectional view taken along the line BB in FIG. 2). FIG. 2 is a partially enlarged perspective view for explaining a coil provided in the actuator shown in FIG. 1. FIG. 2 is a partially enlarged perspective view for explaining a piezoresistive element and its wiring provided in the actuator shown in FIG. 1. It is a top view which shows 2nd Embodiment of the actuator of this invention. FIG. 7 is a partially enlarged perspective view for explaining a piezoresistive element provided in the actuator shown in FIG. 6 and its wiring. It is a partial expansion perspective view for demonstrating the piezoresistive element with which the actuator concerning 3rd Embodiment of this invention was equipped, and its wiring. It is a partial expansion perspective view for demonstrating the piezoresistive element with which the actuator concerning 4th Embodiment of this invention was equipped, and its wiring. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus (printer) including an optical scanner of the present invention. It is a figure which shows schematic structure of the exposure unit with which the image forming apparatus of FIG. 10 was equipped. It is typical sectional drawing which shows an example of an image forming apparatus (imaging display) provided with the optical scanner of this invention.

Explanation of symbols

  1, 1A ... Actuator 2 ... Base 21 ... Movable plate 22, 23 ... Shaft member 24 ... Support part 211 ... Light reflecting part 212 ... Coil 213 ... Junction point 221, 231 ...... Wiring 222 232 ...... First junction 223 233 ... Second junction 241, 242 ...... Terminal 214 ...... Wiring 41, 42 …… Magnet 3 ... support body 110, 119 ... image forming apparatus 111 ... photoconductor 112 ... charging unit 113 ... exposure unit 114 ... development unit 115 ... transfer unit 116 ... cleaning unit 117 ····················································· Fixing device 131 ······································· Collimator lens 145 ... Holder 146 ... Shaft 151 ... Intermediate transfer belt 152 ... Primary transfer roller 153 ... Driven roller 154 ... Drive roller 155 ... Secondary transfer roller 161 ... Cleaning blade 171 ... Feed roller 172 ... Registration roller 173 ... Discharge roller pair 174, 176 ... Conveyance roller pair 175 ... Conveyance path 191 to 193 ... Light source 194 ... Cross dichroic Prism 195 ... Galvano mirror 196 ... Fixed mirror 197 ... Screen 51, 52 ... Piezoresistive elements 53, 53A, 55, 55A, 55B ... Wiring group 54, 56 ... Electrode group 57 , 58 ... Resin layer 59 ... Bump 521 ... Piezoresistive area 522, 523 ... First terminal 524, 525 ... 2nd terminals 541 to 544, 561 to 564 ... Electrodes 551 to 554, 551A to 554A, 551B to 554B ... Wiring 571 ... Body part 572 to 575 ... Extension Part 581 ... part P ... recording medium X ... center axis of rotation E ... Electric field

Claims (10)

A vibrating portion including a movable plate and a pair of shaft members that support the movable plate;
A support part for supporting the vibration part;
A piezoresistive element provided in the vibrating section for detecting the behavior of the movable plate;
A plurality of electrodes provided on the support;
A resin layer formed such that a part is bonded to the vibration part and the support part, and the remaining part is separated from each shaft member;
Is deposited on the resin layer, and a wiring for electrically connecting the said piezoresistive elements each electrode,
Drive means for rotating the movable plate with torsional deformation of each shaft member;
The wiring is disposed such that at least a part thereof is separated from each shaft member ,
The resin layer is provided such that a surface of the resin layer on the wiring side is the vibrating portion side, and each of the wirings is bonded to the piezoresistive element via a conductive bump,
The resin layer collectively supports the plurality of wires on the shaft member side with respect to the support portion,
The actuator, wherein the resin layer has a portion extending to the side opposite to the shaft member with respect to the support portion, and the plurality of electrodes are joined to the portion . The piezoresistive element is provided on at least one shaft member among the shaft member of the pair, the wire actuator according to claim 1 is provided along the at least either of the shaft member. The actuator according to claim 2 , wherein the piezoresistive element includes a piezoresistive region provided on the shaft member and at least a pair of terminals provided in the piezoresistive region so as to be separated from each other. The at least one pair of terminals are arranged in parallel to each other in a direction perpendicular to the axis of the shaft member, and a pair of first terminals arranged in parallel to each other in the axial direction of the shaft member. The actuator according to claim 3 , comprising a pair of second terminals. The piezoresistive element is the provided on the shaft member, the wire actuator according to any one of claims 2 to 4 effect on the shaft member of said pair is provided to be equal to each other . The piezoresistive element actuator according to any one of the the preceding claims 2 are provided on the end of the supporting portion side of the shaft member 5. The actuator according to any one of claims 1 to 6 , wherein the movable plate and the shaft members are integrally formed of silicon. The wire actuator according to any one of claims 1 to 7 are made of metal. A vibrating portion including a movable plate provided with a light reflecting portion and a pair of shaft members that support the movable plate;
A support part for supporting the vibration part;
A piezoresistive element provided in the vibrating section for detecting the behavior of the movable plate;
A plurality of electrodes provided on the support;
A resin layer formed such that a part is bonded to the vibration part and the support part, and the remaining part is separated from each shaft member;
Is deposited on the resin layer, and a wiring for electrically connecting the said piezoresistive elements each electrode,
Drive means for rotating the movable plate with torsional deformation of each shaft member;
Configured to scan the light reflected by the light reflecting portion;
The wiring is disposed such that at least a part thereof is separated from each shaft member ,
The resin layer is provided such that a surface of the resin layer on the wiring side is the vibrating portion side, and each of the wirings is bonded to the piezoresistive element via a conductive bump,
The resin layer collectively supports the plurality of wires on the shaft member side with respect to the support portion,
The optical scanner is characterized in that the resin layer has a portion extending to the side opposite to the shaft member with respect to the support portion, and the plurality of electrodes are joined to the portion . A vibrating portion including a movable plate provided with a light reflecting portion and a pair of shaft members that support the movable plate;
A support part for supporting the vibration part;
A piezoresistive element provided in the vibrating section for detecting the behavior of the movable plate;
A plurality of electrodes provided on the support;
A resin layer formed such that a part is bonded to the vibration part and the support part, and the remaining part is separated from each shaft member;
Is deposited on said resin layer, and a wiring for electrically connecting the said piezoresistive elements each electrode,
Drive means for rotating the movable plate with torsional deformation of each shaft member;
The light reflected by the light reflecting portion is scanned to form an image,
The wiring is disposed such that at least a part thereof is separated from each shaft member ,
The resin layer is provided such that a surface of the resin layer on the wiring side is the vibrating portion side, and each of the wirings is bonded to the piezoresistive element via a conductive bump,
The resin layer collectively supports the plurality of wires on the shaft member side with respect to the support portion,
The image forming apparatus , wherein the resin layer has a portion extending to the opposite side to the shaft member with respect to the support portion, and the plurality of electrodes are bonded to the portion.

Images