Patent Description:
For example, a rotation drive actuator is used in a scanner in a multifunction peripheral, a laser beam printer and other apparatuses. Specifically, a rotary reciprocating drive actuator changes a reflection angle of a laser beam by rotating a mirror of the scanner in a reciprocating manner to realize optical scanning with respect to an object.

Conventionally, the scanner using a galvanometer motor as this type of the rotary reciprocating drive actuator is disclosed in such as PTL <NUM> and PTL <NUM>. Various types of the galvanometer motor, such as a coil movable type in which a coil is attached to the mirror and a structure disclosed in PTL <NUM>, are known.

Incidentally, PTL <NUM> discloses a beam scanner in which four permanent magnets are provided on a rotating shaft to which the mirror is attached so as to be magnetized in the radial direction of the rotating shaft, and a core having magnetic poles around which the coil is wound is disposed so as to sandwich the rotating shaft. PTL <NUM> discloses a rotary reciprocating drive actuator comprising: a base portion; a movable magnet; and a drive unit. Document <CIT> relates to a similar actuator.

By the way, in the rotary reciprocating drive actuator of the coil movable type, heat generated by the coil during driving may adversely affect such as a surface state of the mirror, a bonding state of the mirror to the rotating shaft and a shape of the mirror including a warp. Further, in the rotary reciprocating drive actuator of the coil movable type, considering a heat generation of the coil at the time of energization, there are problems that an input current to the coil is difficult to increase and a size and an amplitude of the mirror to be a movable body are difficult to increase. Further, there is a problem that an assemblability is poor, because it is necessary to pull out wirings to the coil to a fixed body side with respect to the mirror to be the movable body.

In PTL <NUM>, since the magnets are disposed on the movable body side, the above problem of the coil movable type can be solved. In PTL <NUM>, however, two magnets per one core pole and a total of four magnets are required in order to make the magnet stationary at the neutral position with respect to the core, that is, in order to position a switching portion of the magnetic pole of the magnet at the center of the core.

Thereby, there is a problem that the amplitude of the movable body is reduced, that is, a swing range is reduced, as compared with the case where an equivalent rotary reciprocating drive actuator is configured by using two poles magnet, for example. Further, since at least four magnets are used, a number of parts is large, the structure is complicated and the assembly is difficult.

Further, in recent years, as a rotary reciprocating drive actuator used in a scanner, a rotary reciprocating drive actuator that has rigidity, impact resistance and vibration resistance, improves assemblability and can achieve high amplitude is desired on the assumption that the mirror to be the movable body is enlarged and the like.

Further, as also described in PTL <NUM>, the rotary reciprocating drive actuator is provided with an angle sensor for detecting a rotation angle of the rotation shaft connected to the mirror. A scanning accuracy as a scanner greatly depends on a detection accuracy of the angle sensor. In order to improve the detection accuracy of the angle sensor, it is necessary to adjust a mounting position of the angle sensor with high accuracy so that the relative relationship between the angle sensor and the other components of the rotary reciprocating drive actuator such as the mirror becomes a determined relationship. Such requirements make it difficult to assemble the rotary reciprocating drive actuator.

The present invention has been made in consideration of the above points, and provides a rotary reciprocating drive actuator which can be easily assembled and can drive a movable object at a high amplitude.

According to one aspect of a rotary reciprocating drive actuator of the present invention, the rotary reciprocating drive actuator comprising:.

According to the present invention, since the magnet position holding portion for magnetically attracting the movable magnet to the reference position is provided, even if the movable object is a large sized mirror, it can be driven at a high amplitude. Further, since the angle sensor portion is attached to the other wall portion with respect to the wall portion to which the drive unit is attached in the pair of wall portions, it can be easily assembled.

<FIG> is an external perspective view of rotary reciprocating drive actuator <NUM> of the embodiment. <FIG> is an exploded perspective view of rotary reciprocating drive actuator <NUM>.

Rotary reciprocating drive actuator <NUM> is used, for example, in a LIDAR (Laser Imaging Detection and Ranging) apparatus. Note that, rotary reciprocating drive actuator <NUM> is also applicable to a scanner in a multifunction peripheral, a laser beam printer and other apparatuses.

Rotary reciprocating drive actuator <NUM> is roughly divided into base portion <NUM>; mirror portion <NUM> rotatably supported by base portion <NUM>; drive unit <NUM> for driving mirror portion <NUM> in a rotary reciprocating manner; and angle sensor portion <NUM> for detecting a rotational angle position of mirror portion <NUM>.

As can be seen from <FIG>, mirror <NUM> is attached to one surface of substrate <NUM> in mirror portion <NUM>. Shaft portion <NUM> is inserted into insertion hole 122a of substrate <NUM>, and substrate <NUM> and shaft portion <NUM> are fastened.

Base portion <NUM> is a member having a substantially U - shaped cross section and having a pair of wall portions 111a and 111b. Insertion hole <NUM> through which shaft portion <NUM> is inserted is formed in each of the pair of wall portions 111a and 111b. Further, notched holes <NUM> communicating insertion holes <NUM> and the outer edges of wall portions 111a and 111b are formed in the pair of wall portions 111a and 111b, respectively.

Thus, shaft portion <NUM> can be disposed at positions of insertion holes <NUM> through notched holes <NUM> in a state where mirror portion <NUM> is fastened to shaft portion <NUM>. In the case where notched holes <NUM> are not provided, a complicated assembly operation is required in which shaft portion <NUM> is inserted into both insertion holes <NUM> of wall portions 111a, 111b and insertion hole 122a of substrate <NUM> while mirror portion <NUM> is disposed between the pair of wall portions 111a and 111b, and shaft portion <NUM> and substrate <NUM> are fastened. In contrast, in the present embodiment, since notched holes <NUM> are formed, shaft portion <NUM> to which mirror portion <NUM> is fastened in advance can be easily inserted into insertion holes <NUM>.

Ball bearings <NUM> are attached to both ends of shaft portion <NUM>. Ball bearings <NUM> are mounted to bearing mounting portions <NUM> formed at the positions of insertion holes <NUM> of the pair of wall portions 111a and 111b. Thus, shaft portion <NUM> is rotatably attached to base portion <NUM> via ball bearings <NUM>, and mirror portion <NUM> to be the movable object is disposed between the pair of wall portions 111a and 111b.

Further, movable magnet <NUM> is fastened to one end of shaft portion <NUM>. Movable magnet <NUM> is disposed inside of drive unit <NUM> and is driven in a rotary reciprocating manner by a magnetic flux generated by drive unit <NUM>.

As described above, in the present embodiment, shaft portion <NUM> to which mirror portion <NUM> to be the movable object is attached is pivotally supported by the pair of wall portions 111a and 111b of base portion <NUM> so as to support mirror portion <NUM> from both sides. Thus, mirror portion <NUM> is supported more firmly than the case where shaft portion <NUM> is pivotally supported in a cantilever manner, and a shock resistance and a vibration resistance are improved.

As can be seen from <FIG>, drive unit <NUM> has core body <NUM> and coil body <NUM>. A coil is provided with a winding inside of coil body <NUM>. Core body <NUM> includes first core body <NUM> and second core body <NUM>. Similarly, coil body <NUM> includes first coil body <NUM> and second coil body <NUM>. Coil body <NUM> is mounted so as to be inserted into a part of core body <NUM>. Thus, when the coil of coil body <NUM> is energized, core body <NUM> is excited.

Core body <NUM> and coil body <NUM> are fixed to fixing plate <NUM>, and fixing plate <NUM> is fixed to wall portion 111a of base portion <NUM> via fastening members <NUM>.

Incidentally, in the present embodiment, drive unit <NUM> further includes bridging core <NUM> and magnet position holding portion <NUM>. Bridging core <NUM> has the same structure as core body <NUM>. Magnet position holding portion <NUM> is made of a magnet. A position of movable magnet <NUM> is magnetically attracted to a movement reference position by a magnetic force of magnet position holding portion <NUM>. This will be described in detail later.

In the example of the present embodiment, core body <NUM> and bridging core <NUM> are laminated cores, and are formed by laminating, for example, silicon steel plates.

Angle sensor portion <NUM> includes circuit board <NUM>; optical sensor <NUM> and connector <NUM> mounted on circuit board <NUM>; encoder disk <NUM>; and case <NUM>. Circuit board <NUM> is fixed to case <NUM> by fastening members <NUM>. Case <NUM> is fixed to wall portion 111b by fastening members <NUM>.

Encoder disk <NUM> is mounted by fastening to shaft portion <NUM> via mounting member <NUM>, and rotates integrally with movable magnet <NUM> and mirror portion <NUM>. That is, mounting member <NUM> has an insertion hole through which shaft portion <NUM> is inserted and fastened, and a flange portion to which encoder disk <NUM> is abutted and fastened, and mounting member <NUM> is fixed to both shaft portion <NUM> and encoder disk <NUM>. As a result, a rotational position of encoder disk <NUM> is the same as a rotational position of shaft portion <NUM>. Optical sensor <NUM> emits light to encoder disk <NUM> and detects the rotational position (angle) of encoder disk <NUM> based on the reflected light. Thus, the rotational positions of movable magnet <NUM> and mirror portion <NUM> can be detected by optical sensor <NUM>.

In the rotary reciprocating drive actuator <NUM> of the present embodiment, the movable body having movable magnet <NUM> and shaft portion <NUM>, and drive unit <NUM> having coil body <NUM>, core body <NUM>, and the like are attached to an outer surface side of one wall portion 111a of the pair of wall portions 111a and 111b of base portion <NUM>. On the other hand, angle sensor portion <NUM> for detecting the rotation angle of shaft portion <NUM> is attached to an outer surface side of the other wall portion 111b of the pair of wall portions 111a and 111b of base portion <NUM>.

This makes it easy to remove angle sensor portion <NUM> and adjust an assembly position thereof. Since angle sensor portion <NUM> can be easily removed, angle sensor portion <NUM> can be easily replaced when a failure occurs in angle sensor portion <NUM>. Further, angle sensor portion <NUM> can be assembled at the final stage of assembly. As a result, the expensive angle sensor portion <NUM> can be assembled after it is confirmed that the assembly of the other components is normal. Therefore, a risk of wasting the expensive angle sensor portion <NUM> due to the assembly failure of the other components can be suppressed.

Next, detailed configuration and operation of rotary reciprocating drive actuator <NUM> will be described with reference to <FIG>.

<FIG> is a side view of rotary reciprocating drive actuator <NUM> of <FIG> viewed from the left side of <FIG>. That is, drive unit <NUM> is mainly shown in <FIG>.

In rotary reciprocating drive actuator <NUM>, the movable body including movable magnet <NUM>, shaft portion <NUM> and other potions is rotatably held by the magnetic attraction force, that is, a magnetic spring, between magnet position holding portion <NUM> and movable magnet <NUM>, so that the movable body is positioned at the movement reference position in the normal state. Here, the normal state is a state where coil body <NUM> is not energized.

Positioning the movable body at the movement reference position means that movable magnet <NUM> is positioned at a neutral position with respect to magnetic poles 211a and 212a of core body <NUM> excited by coil body <NUM> in the present embodiment, and it is a position capable of rotating similarly in either one direction and the other direction around the shaft (normal rotation and reverse rotation viewed from shaft portion <NUM> side). In other words, the movement reference position at which magnet position holding portion <NUM> magnetically attracts movable magnet <NUM> is a rotational center position of the rotating reciprocation of movable magnet <NUM>. When the movable body is positioned at the movement reference position, magnetic pole switching portions 161c of movable magnet <NUM> are positioned at positions facing the magnetic poles of coil body <NUM> side.

By the cooperation of movable magnet <NUM> and coil body <NUM>, shaft portion <NUM> of the movable body rotates in one direction and in the other direction around the shaft from the movement reference position in a reciprocating manner with respect to base portion <NUM>.

Movable magnet <NUM> is formed in a ring shape, and has an even number of magnetic poles 161a, 161b in which an S - pole (a South pole) and an N - pole (a North pole) are alternately magnetized in a direction orthogonal to the rotational axis direction of shaft portion <NUM> at an outer periphery of shaft portion <NUM>. Although movable magnet <NUM> is magnetized to two poles in the present embodiment, it may be magnetized to two or more poles depending on an amplitude at the time of movement.

The even number of magnetic poles 161a and 161b has magnetization surfaces of different polarities facing opposite direction to each other across shaft portion <NUM>. In the present embodiment, magnetic poles 161a and 161b have different polarities in which a plane along the axial direction of shaft portion <NUM> is as a boundary thereof.

Further, the even number of magnetic poles 161a and 161b is configured to magnetize at equal intervals at the outer periphery of shaft portion <NUM>.

As described above, in movable magnet <NUM>, the even number of magnetic poles 161a and 161b forming the S - pole and the N - pole is alternately arranged at the outer periphery of shaft portion <NUM>, and the magnetic poles 161a and 161b are arranged at equal intervals.

More specifically, in movable magnet <NUM>, each of semicircular portions constitutes different magnetic poles 161a and 161b. Arc shaped curved surfaces of the semicircular portions are magnetization surfaces of different magnetic poles 161a and 161b, and the magnetization surfaces of different magnetic poles 161a and 161b are configured to extend in a circumferential direction around the shaft. In other words, the magnetization surfaces of magnetic poles 161a and 161b are arranged in a direction orthogonal to the axial direction of shaft portion <NUM>, and are rotated to be able to face to magnetic pole 211a of first core body <NUM> and magnetic pole 212a of second core body <NUM>, respectively.

A number of magnetic poles of movable magnet <NUM> is equal to a number of magnetic poles of core body <NUM>.

Magnetic pole switching portions 161c of magnetic poles 161a and 161b of movable magnet <NUM> are located at positions facing center positions in a width direction of magnetic pole 211a of first core body <NUM> and magnetic pole 212a of second core body <NUM> when coil body <NUM> is not energized.

First core body <NUM> and second core body <NUM> are parallel to each other, and have core portions 211b and 212b (see <FIG>) which are formed so as to sandwich movable magnet <NUM>. First coil body <NUM> and second coil body <NUM> are respectively extrapolated to core portions 211b and 212b. Bridging core <NUM> is provided to be bridged between one end portions of core portions 211b and 212b, and magnetic poles 211a and 212a are formed continuously on the other end portions of core portions 211b and 212b.

As described above, core body <NUM> has core portions 211b and 212b to which first coil body <NUM> and second coil body <NUM> are extrapolated; magnetic poles 211a and 212a; and bridging core <NUM> provided to be bridged between the end portions opposite to magnetic poles 211a and 212a. That is, core body <NUM> is configured from three split bodies. Among these split bodies, bridging core <NUM> is provided with magnet position holding portion <NUM>.

Two magnetic poles 211a and 212b are disposed to face each other so as to sandwich movable magnet <NUM> with air gap G between them and the outer periphery of movable magnet <NUM>.

Magnet position holding portion <NUM>, which is disposed to face movable magnet <NUM> with air gap G therebetween, is attached to bridging core <NUM> so as to project convexly toward movable magnet <NUM> side.

Magnet position holding portion <NUM> is, for example, a magnet whose opposing surface is magnetized to the N - pole (see <FIG>). Magnet position holding portion <NUM> may be formed integrally with bridging core <NUM>.

Magnet position holding portion <NUM> functions as a magnetic spring together with movable magnet <NUM> by the magnetic attraction force generated between it and movable magnet <NUM>, and positions and holds the position of rotating movable magnet <NUM> at the movement reference position.

Magnet position holding portion <NUM> is a magnet magnetized toward movable magnet <NUM>. Magnet position holding portion <NUM> positions magnetic pole switching portions 161c of movable magnet <NUM> at positions facing magnetic poles 211a and 212a when movable magnet <NUM> is positioned at the movement reference position. As described above, magnet position holding portion <NUM> and movable magnet <NUM> are attracted to each other, and magnet position holding portion <NUM> can position movable magnet <NUM> at the movement reference position. Thus, magnetic pole switching portions 161c of movable magnet <NUM> face magnetic pole 211a of first core body <NUM> and magnetic pole 212a of second core body <NUM>. At this position, drive unit <NUM> generates the maximum torque to stably drive the movable body.

Further, since movable magnet <NUM> is magnetized with two poles, the movable object can be easily driven at a high amplitude and vibration performance can be improved by cooperation with core body <NUM>.

<FIG> and <FIG> are views for explaining an operation of a magnetic circuit of rotary reciprocating drive actuator <NUM>.

When coil body <NUM> (<NUM>, <NUM>) is not energized, movable magnet <NUM> is positioned at the movement reference position by the magnetic attraction force between magnet position holding portion <NUM> and movable magnet <NUM>, that is, the magnetic spring.

In this movement reference position (hereinafter, the movement reference position may be referred to as a normal state), one of magnetic poles 161a and 161b of movable magnet <NUM> is attracted to magnet position holding portion <NUM>, and magnetic pole switching portions 161c are positioned at positions facing the center positions of magnetic pole 211a of first core body <NUM> and magnetic pole 212a of second core body <NUM>.

When coil body <NUM> is energized, coil body <NUM> (<NUM>, <NUM>) excite first core body <NUM> and second core body <NUM>.

When coil body <NUM> is energized in the direction shown in <FIG>, magnetic pole 211a is magnetized to the N - pole, and magnetic pole 212a is magnetized to the S - pole.

As a result, in first core body <NUM>, a magnetic flux is formed in which the magnetic flux is emitted from magnetic pole 211a magnetized to the N - pole to movable magnet <NUM>, flows through movable magnet <NUM>, magnet position holding portion <NUM>, and bridging core <NUM> in this order, and enters into core portion 211b.

In second core body <NUM>, the magnetic flux is emitted from core portion 212b to bridging core <NUM> side, flows through bridging core <NUM>, magnet position holding portion <NUM>, and movable magnet <NUM> in this order, and enters magnetic pole 212a.

As a result, magnetic pole 211a magnetized to the N - pole is attracted to the S - pole in movable magnet <NUM>, magnetic pole 212a magnetized to the S - pole is attracted to N - pole in movable magnet <NUM>, a torque in the F direction is generated around the axis of shaft portion <NUM> in movable magnet <NUM>, and movable magnet <NUM> rotates in the F direction. Accordingly, shaft portion <NUM> also rotates, and mirror portion <NUM> fixed to shaft portion <NUM> also rotates.

Next, as shown in <FIG>, when the energization direction of coil body <NUM> is switched to the opposite direction, magnetic pole 211a is magnetized to the S - pole, magnetic pole 212a is magnetized to the N - pole, and the flow of the magnetic flux is also reversed.

As a result, magnetic pole 211a magnetized to the S - pole is attracted to the N - pole in movable magnet <NUM>, magnetic pole 212a magnetized to the N - pole is attracted to the S - pole in movable magnet <NUM>, a torque in the direction opposite to the F direction is generated around the axis of shaft portion <NUM> in movable magnet <NUM>, and movable magnet <NUM> rotates in the direction opposite to the F direction. Accordingly, shaft portion <NUM> also rotates in the opposite direction, and mirror portion <NUM> fixed to shaft portion <NUM> also rotates in the opposite direction. By repeating these motions, rotary reciprocating drive actuator <NUM> drives mirror portion <NUM> in a rotary reciprocating manner.

In practice, rotary reciprocating drive actuator <NUM> is driven by an alternating current wave input from a power supply unit (for example, corresponding to drive signal supply unit <NUM> in <FIG>) to coil body <NUM>. That is, the energization direction of coil body <NUM> is periodically switched, and the torque in the F direction around the axis and the torque in the direction opposite to the F direction (- F direction) alternately act on the movable body. Thus, the movable body is driven in a rotary reciprocating manner.

Incidentally, at the time of switching the energization direction, the magnetic attraction force between magnet position holding portion <NUM> and movable magnet <NUM> is generated, that is, magnetic spring torque FM (<FIG>) or - FM (<FIG>) is generated by the magnetic spring, and movable magnet <NUM> is urged to the movement reference position.

The driving principle of rotary reciprocating drive actuator <NUM> will be briefly described below. In rotary reciprocating drive actuator <NUM> of the present embodiment, when the moment of inertia of the movable body is J [kg·m<NUM>] and the spring constant in the torsional direction of the magnetic spring (magnetic poles 211a and 212a, magnet position holding portion <NUM>, and movable magnet <NUM>) is Ksp, the movable body vibrates (rotary reciprocates) with respect to base portion <NUM> at a resonance frequency Fr [Hz] calculated by the equation (<NUM>). [Equation <NUM>] <MAT>.

Since the movable body constitutes a mass portion in a vibration model of a spring - mass system, when an alternating current wave having a frequency equal to the resonance frequency Fr of the movable body is inputted to coil body <NUM>, the movable body enters a resonance state. That is, by inputting the alternating current wave having a frequency substantially equal to the resonance frequency Fr of the movable body to coil body <NUM> from the power supply unit, the movable body can be efficiently vibrated.

A motion equation and a circuit equation showing the driving principle of rotary reciprocating drive actuator <NUM> are shown below. Rotary reciprocating drive actuator <NUM> is driven based on the motion equation expressed by the equation (<NUM>) and the circuit equation expressed by the equation (<NUM>). [Equation <NUM>] <MAT>.

That is, the moment of inertia J [kg·m<NUM>], the rotation angle θ(t) [rad], the torque constant Kt [N·m/A], the current i(t) [A], the spring constant Ksp [N·m/rad], the damping coefficient D [N·m/(rad/s)], the load torque TLoss [N·m], and the like of the movable body in rotary reciprocating drive actuator <NUM> can be appropriately changed within the range satisfying the equation (<NUM>). Further, the voltage e(t) [V], the resistance R [Ω], the inductance L [H], and the counter electromotive force constant Ke [V/(rad/s)] can be appropriately changed within the range satisfying the equation (<NUM>).

As described above, rotary reciprocating drive actuator <NUM> can efficiently obtain a large vibration output when the coil is energized by the alternating current wave corresponding to the resonance frequency Fr determined by the moment of inertia J of the movable body and the spring constant Ksp of the magnetic spring.

According to rotary reciprocating drive actuator <NUM> of the present embodiment, since a torque generation efficiency is high, heat is hard to transfer to mirror <NUM> which is the movable object, and as a result, a flatness of a reflection surface of mirror <NUM> can be ensured with high accuracy. Further, a manufacturing efficiency is high, an assembly accuracy is good, and even if the movable object is a large sized mirror, it can be driven at a high amplitude.

Note that, rotary reciprocating drive actuator <NUM> of the present embodiment can be driven by resonance, but can also be driven by non - resonance.

Next, a configuration of a scanner system using rotary reciprocating drive actuator <NUM> will be briefly described.

<FIG> is a block diagram showing an essential configuration of scanner system 300A using rotary reciprocating drive actuator <NUM>.

Scanner system 300A includes laser emitting unit <NUM>; laser control unit <NUM>; drive signal supply unit <NUM>; and position control signal calculation unit <NUM> in addition to rotary reciprocating drive actuator <NUM>.

Laser emitting unit <NUM> includes, for example, an LD (laser diode) to be a light source; a lens system for converging a laser beam output from the light source, and the like. Laser control unit <NUM> controls laser emitting unit <NUM>. The laser beam obtained by laser emitting unit <NUM> is incident on mirror <NUM> of rotary reciprocating drive actuator <NUM>.

Position control signal calculation unit <NUM> generates and outputs a drive signal for controlling shaft portion <NUM> (mirror <NUM>) to be the target angular position with reference to the angular position of shaft portion <NUM> (mirror <NUM>) acquired by angle sensor portion <NUM> and the target angular position. For example, position control signal calculation unit <NUM> generates a position control signal on the basis of the obtained angular position of shaft portion <NUM> (mirror <NUM>) and a signal indicating the target angular position converted using sawtooth waveform data, and the like stored in a waveform memory which is not illustrated, and outputs the position control signal to drive signal supply unit <NUM>.

Based on the position control signal, drive signal supply unit <NUM> supplies the drive signal to coil body <NUM> of rotary reciprocating drive actuator <NUM> such that the angular position of shaft portion <NUM> (mirror <NUM>) becomes a desired angular position. Thus, scanner system 300A can emit a scanning light from rotary reciprocating drive actuator <NUM> to a predetermined scanning area.

<FIG> is an external perspective view showing an example of the configuration of the scanner system, in which the same reference signs are assigned to the corresponding parts in <FIG>. In scanner system 300C, laser unit <NUM> is provided on base portion <NUM>. Laser unit <NUM> includes laser emitting unit <NUM> and laser light receiving unit <NUM>. Thus, a laser beam emitted from laser emitting unit <NUM> is reflected by mirror portion <NUM> of rotary reciprocating drive actuator <NUM> to be a scanning light, and irradiated to a scanning object. The scanning light reflected by the scanning object is received by laser light receiving unit <NUM> through mirror portion <NUM>. Note that, in rotary reciprocating drive actuator <NUM> of scanner system 300C, as compared with rotary reciprocating drive actuator <NUM> of <FIG>, a bottom plate of base portion <NUM> is extended in a depth direction in the drawing, and laser unit <NUM> is installed in this extended portion.

<FIG> is an external perspective view showing another configuration example of the scanner system, in which the same reference signs are assigned to the corresponding parts in <FIG>. Scanner system 300D has the same configuration as scanner system 300C except that laser unit <NUM> is disposed at a different position.

As shown in <FIG> and <FIG>, since laser unit <NUM> is provided in base portion <NUM> of rotary reciprocating drive actuator <NUM>, laser unit <NUM> can be easily and accurately attached to rotary reciprocating drive actuator <NUM>.

Here, if a function as a scanner is to be realized, laser unit <NUM> may not have laser light receiving unit <NUM> but may have only laser emitting unit <NUM>. However, in the present embodiment, since laser unit <NUM> also has laser light receiving unit <NUM>, and laser unit <NUM> is provided in base portion <NUM> of rotary reciprocating drive actuator <NUM>, as a result, laser light receiving unit <NUM> as the light detecting unit is a configuration in which laser light receiving unit <NUM> is directly attached to the scanner portion. Thus, the positioning accuracy of the laser light receiving unit to the scanner portion can be easily enhanced.

As described above, rotary reciprocating drive actuator <NUM> of the present embodiment includes base portion <NUM>; movable magnet <NUM> fixed to shaft portion <NUM> to which the movable object (mirror portion <NUM> in the example of the embodiment) is connected; and drive unit <NUM> having core body <NUM> and coil body <NUM> for generating the magnetic flux in core body <NUM> when the current is supplied, and driving movable magnet <NUM> in a rotary reciprocating manner by the electromagnetic interaction between the magnetic flux generated from core body <NUM> and movable magnet <NUM>. Further, in rotary reciprocating drive actuator <NUM>, movable magnet <NUM> is formed in the ring shape, and is configured by alternately magnetizing the even number of magnetic poles forming the S - pole and the N - pole at the outer periphery of shaft portion <NUM>; the number of magnetic poles of core body <NUM> and the number of magnetic poles of movable magnet <NUM> are equal to each other; the even number of magnetic poles of core body <NUM> is respectively arranged to face movable magnet <NUM> with the air gap therebetween on the outer peripheral side of shaft portion <NUM>; and drive unit <NUM> is provided with magnet position holding portion <NUM> which is a magnetic material provided to face movable magnet <NUM> and magnetically attracts movable magnet <NUM> to a reference position.

Thus, since movable magnet <NUM> is magnetically attracted to the neutral position (movement reference position) by magnet position holding portion <NUM> every time the energization direction is switched, good energy efficiency, good responsiveness, and high amplitude rotary reciprocating drive are realized. Further, compared with the rotary reciprocating drive actuator of the coil movable type, the heat generated by coil body <NUM> is hard to transfer to the movable object, and when the movable object is a mirror, it is possible to prevent adverse effects (bond deterioration, warpage, etc.) of the heat from affecting the mirror.

In addition, in rotary reciprocating drive actuator <NUM> of the present embodiment, the pair of wall portions 111a and 111b for rotatably supporting shaft portion <NUM> via bearings (ball bearings <NUM>) are provided in base portion <NUM>, the movable object (mirror portion <NUM> in the example of the embodiment) is disposed between the pair of wall portions 111a and 111b. Drive unit <NUM> is attached to the outer surface side of one wall portion 111a of the pair of wall portions 111a and 111b, and angle sensor portion <NUM> for detecting the rotation angle of shaft portion <NUM> is attached to the outer surface side of the other wall portion 111b of the pair of wall portions 111a and 111b.

This makes it easy to remove angle sensor portion <NUM> and adjust the assembly position thereof. Since angle sensor portion <NUM> can be easily removed, angle sensor portion <NUM> can be easily replaced when the failure occurs in angle sensor portion <NUM>. Further, angle sensor portion <NUM> can be assembled at the final stage of assembly. As a result, the expensive angle sensor portion <NUM> can be assembled after it is confirmed that the assembly of the other components is normal. Therefore, the risk of wasting the expensive angle sensor portion <NUM> due to the assembly failure of the other components can be suppressed.

In one aspect of the present invention, the reference position at which magnet position holding portion <NUM> magnetically attracts movable magnet <NUM> is the rotational center position of the rotating reciprocation of movable magnet <NUM>.

In one aspect of the present invention, in movable magnet <NUM>, the even number of magnetic poles is magnetized at equal intervals at the outer periphery of shaft portion <NUM>.

In one aspect of the present invention, magnet position holding portion <NUM> is disposed at the position between the even number of magnetic poles of core body <NUM> and at the position facing movable magnet <NUM> in the radial direction of movable magnet <NUM>.

These configurations can maximize a driving torque and stabilize a direction of the driving torque.

The above embodiments are merely specific examples for carrying out the present invention, and the technical scope of the present invention should not be construed to be limited by them. That is, the present invention can be implemented in a variety of ways without departing from the scope of the invention that is defined by the appended claims.

In the above embodiment, the case where wall portion 111b to attach angle sensor portion <NUM> is formed integrally with base portion <NUM> is described. A wall portion to attach angle sensor portion <NUM>, however, may not be formed integrally with base portion <NUM> but may be attached to the base portion later.

Specifically, as shown in <FIG> in which the same reference signs are assigned to the corresponding portions in <FIG> and <FIG> in which the same reference signs are assigned to the corresponding portions in <FIG>, rotary reciprocating drive actuator 100A has an L shaped base portion <NUM>'. In rotary reciprocating drive actuator 100A, wall portion 111c to which angle sensor portion <NUM> is attached to the inner surface is attached to base portion <NUM>'. In this configuration, since wall portion 111c can be removed from or relatively moved with respect to base portion <NUM>' , angle sensor portion <NUM> can also be easily removed and the assembling position can be easily adjusted. However, as in the above embodiments, the configuration in which angle sensor portion <NUM> is attached to the outer surface side of wall portion 111b is easier to remove and adjust the assembling position of angle sensor portion <NUM>.

In the above embodiments, the case where ball bearings <NUM> are used as bearings for rotatably attaching shaft portion <NUM> to base portion <NUM> is described. The present invention, however, is not limited thereto, and an air bearing, an oil bearing and other bearings may be used as bearings.

In the above embodiments, the case where drive unit <NUM> is mounted on the outer surface side of wall portion 111a is described. The position of drive unit <NUM>, however, is not limited thereto. Dive unit <NUM> may be mounted, for example, on the inner surface side of wall portion 111a.

In the above embodiments, the case where the movable object driven by rotary reciprocating drive actuator <NUM>, that is, the movable object attached to shaft portion <NUM> is mirror portion <NUM> is described. The movable object, however, is not limited thereto. For example, a camera or the like may be the movable object.

Claim 1:
A rotary reciprocating drive actuator comprising:
a base portion (<NUM>);
a movable magnet (<NUM>) fixed to a shaft portion (<NUM>) to which a movable object (<NUM>) is connected; and
a drive unit (<NUM>) having a core body (<NUM>) and a coil body (<NUM>) for generating a magnetic flux in the core body (<NUM>) when current is supplied, and driving the movable magnet (<NUM>) in a rotary reciprocating manner by an electromagnetic interaction between the magnetic flux generated from the core body (<NUM>) and the movable magnet (<NUM>),
wherein the movable magnet (<NUM>) is formed in a ring shape, and is configured by alternately magnetizing an even number of magnetic poles (161a, 161b) forming an S - pole and an N - pole at an outer periphery of the shaft portion (<NUM>);
a number of magnetic poles (211a, 212a) of the core body (<NUM>) and a number of magnetic poles (161a, 161b) of the movable magnet (<NUM>) are equal to each other;
an even number of magnetic poles (211a, 212a) of the core body (<NUM>) is respectively arranged to face the movable magnet (<NUM>) with an air gap therebetween on the outer peripheral side of the shaft portion (<NUM>);
the drive unit (<NUM>) is provided with a magnet position holding portion (<NUM>) which is a magnetic material provided to face the movable magnet (<NUM>) and magnetically attracts the movable magnet (<NUM>) to a reference position;
a pair of wall portions (111a, 111b) is erected on the base portion (<NUM>) to rotatably support the shaft portion (<NUM>) via a bearing (<NUM>), and the movable object (<NUM>) is disposed between the pair of wall portions (111a, 111b);
the drive unit (<NUM>) is attached to one wall portion (111a) of the pair of wall portions (111a, 111b), and an angle sensor portion (<NUM>) for detecting the rotation angle of the shaft portion (<NUM>) is attached to the other wall portion (111b) of the pair of wall portions (111a, 111b); and
the angle sensor portion (<NUM>) includes an optical sensor (<NUM>) and an encoder disk (<NUM>) that is mounted by fastening to the shaft portion (<NUM>) via a mounting member (<NUM>) to rotate integrally with the movable magnet (<NUM>) and the movable object (<NUM>), and a rotational position of the encoder disk (<NUM>) is detected by the optical sensor (<NUM>).