JP2010256811A - Galvano scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a galvano scanner in which the magnetic path of a movable part is composed by permanent magnets only, inertia is reduced by making movable parts light, magnetic flux is increased by increasing the volume of permanent magnets, and a high acceleration is available by suppressing the increase in the electric current supplied to a coil. <P>SOLUTION: The galvano scanner includes: a holding member 3 made of a resin, which has a back face shaped in a semicylindrical face 3b and holds a reflecting mirror 2 so that the center axis O of the semicylindrical face 3b is located at the anti-diagonal face of a reflecting mirror 2; the permanent magnets 5 provided as a unit with the holding member 3 and configuring the movable part together with the holding member; a base member 9 which supports the holding member 3 freely turnably around the center axis O; a core 7 disposed on the base member 9 so as to face the semicylindrical face 3b of the holding member 3; and a coil 8 fixed on the core 7 and drives the holding member 3 to turn around the center axis O by cooperating with the permanent magnets 5. The holding member 3 is made of a nonmagnetic resin material and the magnetic path of the movable part is composed by the permanent magnets 5 only. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a galvano scanner that rotates an optical member to reflect or diffract polarized light.

  In a conventional galvano scanner, a permanent magnet having a semi-cylindrical surface formed on a lower surface is attached to a holding member that holds a reflecting mirror, and an air bearing that rotatably supports the semi-cylindrical surface of the permanent magnet by an air film is fixed to a base member. In addition, a coil is arranged between the air bearing and the base member, and the holding member is urged to the air bearing by the magnetic force of the permanent magnet (see, for example, Patent Document 1).

JP 2000-81588 A

In a conventional galvano scanner, a holding member that holds a reflection mirror constitutes a magnetic circuit together with a permanent magnet and a base member. Therefore, the holding member is made of a heavy magnetic material, and the inertia of the movable part increases. Moreover, since the holding member does not have a magnetomotive force, it does not contribute to an increase in magnetic flux. Therefore, the conventional galvano scanner cannot cope with high acceleration. In other words, in the conventional galvano scanner, in order to achieve high acceleration, it is necessary to increase the current flowing through the coil to obtain a high torque.
However, if the current flowing through the coil is increased, coil joule loss and magnet vortex loss increase, so the amount of heat generated in the coil and magnet increases, deviating from the operating temperature range of the encoder, and the permanent magnet is thermally demagnetized. This causes a problem that the torque decreases.

  The present invention has been made in order to solve such a problem. The magnetic path of the movable part is constituted only by permanent magnets, the holding member can be made of a light non-magnetic material, and It is an object of the present invention to obtain a galvano scanner capable of reducing inertia, increasing the volume of a permanent magnet, increasing magnetic flux, and suppressing increase in energization current to a coil and realizing high acceleration.

  The galvano scanner according to the present invention includes a holding member that holds the optical member such that the back surface has an arc surface, and the central axis of the arc surface is located on the anti-slope or polarization plane of the optical member, and the holding member is integrated with the holding member. A permanent magnet that forms a movable part together with the holding member, a base member that rotatably supports the holding member around the central axis, and the base that faces the arc surface of the holding member. A core disposed on the member, and a coil that is fixed to the core and that rotates the holding member around the central axis in cooperation with the permanent magnet, wherein the holding member is a non-magnetic resin. The magnetic path of the movable part is made of only the permanent magnet.

  According to this invention, since the magnetic path in the movable part holding the optical member is composed of only permanent magnets, the magnet volume increases, the amount of magnetic flux increases, and the torque can be increased. Furthermore, since the holding member is made of a resin material, the weight of the holding member can be reduced and the inertia of the movable portion can be reduced. Accordingly, the torque per inertia of the movable part (torque / movable part inertia) increases, and a high acceleration can be obtained without a large increase in loss.

It is a perspective view which shows the galvano scanner which concerns on Embodiment 1 of this invention. It is a disassembled perspective view explaining the structure of the galvano scanner which concerns on Embodiment 1 of this invention. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. It is a cross-sectional view which shows the structure of the galvano scanner which concerns on Embodiment 2 of this invention. It is a cross-sectional view which shows the structure of the galvano scanner which concerns on Embodiment 3 of this invention. It is a cross-sectional view which shows the structure of the galvano scanner which concerns on Embodiment 4 of this invention.

  Hereinafter, preferred embodiments of the galvano scanner of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
1 is a perspective view showing a galvano scanner according to Embodiment 1 of the present invention, FIG. 2 is an exploded perspective view for explaining the configuration of the galvano scanner according to Embodiment 1 of the present invention, and FIG. It is III arrow sectional drawing.

  1 to 3, a galvano scanner 1 includes a reflection mirror 2 as an optical member, a back surface formed on a semi-cylindrical surface 3b, and a central axis O of the semi-cylindrical surface 3b positioned on the reflection surface of the reflection mirror 2. As described above, the holding member 3 that holds the reflecting mirror 2 on the mirror mounting surface 3a, the permanent magnet 5 that is provided integrally with the holding member 3, and the holding member 3 are rotatable about the central axis O of the semi-cylindrical surface 3b. The base member 9 to be supported and a semi-cylindrical body whose inner peripheral surface is a semi-cylindrical surface having a larger radius of curvature than the semi-cylindrical surface 3b of the holding member 3, and the central axis of the inner peripheral surface coincides with the central axis O. Thus, the core 7 made of a dust core held by the base member 9 so as to face the semi-cylindrical surface 3 b of the holding member 3 and the inner peripheral surface of the core 7 are arranged and cooperates with the permanent magnet 5. A coil 8 for driving the holding member 3 around the central axis O of the semi-cylindrical surface 3b; It is equipped with a. Here, the semi-cylindrical surface is a curved surface (arc surface) formed by collecting arcs having a central angle of 180 ° in the axial direction of the central axis with the center coincident with the central axis.

Here, each configuration of the galvano scanner 1 will be specifically described.
The reflection mirror 2 is manufactured in a rectangular flat plate shape, and the surface is a reflection surface.
The holding member 3 is a non-magnetic resin molded body having an upper surface as a flat mirror mounting surface 3a and a back surface as a semi-cylindrical surface 3b. The pair of rotating shafts 4 are molded integrally with the holding member 3 so as to face each other with the mirror mounting surface 3a interposed therebetween so that the axial center thereof coincides with the central axis O of the semi-cylindrical surface 3b.

  The permanent magnet 5 is a neodymium sintered magnet that is manufactured in a curved strip shape having an arc shape having a predetermined thickness in a cross section perpendicular to the length direction, and having a magnetization orientation direction 6 in the circumferential direction of the arc shape in cross section. . The permanent magnet 5 has a longitudinal direction parallel to the central axis O of the semi-cylindrical surface 3b, an outer peripheral surface having a cross-sectional arc shape directed toward the central axis O of the semi-cylindrical surface 3b, and both sides of the cross-sectional arc shape. The surface is flush with the semi-cylindrical surface 3b and is molded integrally with the holding member 3. The permanent magnet 5 is configured by a bisector of a central angle of the holding member 3 in the direction of the central axis O and symmetrical with respect to a plane orthogonal to the central axis O and the central angle of the semi-cylindrical surface 3b of the holding member 3. The holding member 3 is disposed so as to be symmetric with respect to the plane. And the outer peripheral surface of the permanent magnet 5 comprises a part of semi-cylindrical surface 3b.

The coil 8 is a flat coil that is formed by winding a conducting wire a predetermined number of times and is formed into a racetrack shape in which both ends of a pair of parallel straight portions 8a and 8b are connected by arc portions.
The base member 9 is formed in a rectangular parallelepiped with a good heat conductive material such as copper, for example, and a concave portion 10 having a semi-cylindrical surface having a radius of curvature equivalent to the outer peripheral surface of the core 7 as an inner peripheral surface 10a is provided on the upper surface. ing. Further, a pair of rolling bearings 11 is mounted on the base member 9 so as to be opposed to each other with the concave portion 10 in between, with the axial center thereof aligned with the central axis of the inner peripheral surface 10a of the concave portion 10. Further, the inflow port 12 and the discharge port 13 are connected to both ends of a cooling water flow path 14 formed inside the base member 9.

In order to assemble the galvano scanner 1 configured as described above, first, the holding member 3 is molded. At this time, the rotating shaft 4 and the permanent magnet 5 are insert-molded into the holding member 3. Next, the reflecting mirror 2 is fixed to the mirror mounting surface 3a of the holding member 3 using an adhesive or the like, and a movable part is produced. Further, the outer peripheral surface of the core 7 is fixed to the inner peripheral surface 10 a of the recess 10 using an adhesive or the like, and the core 7 is stored and held in the recess 10. Next, the length direction of the straight portions 8a and 8b of the coil 8 is parallel to the axial direction of the core 7 (the axial direction of the central axis of the inner peripheral surface 10a) and is in contact with the inner peripheral surface of the core 7 and on the inner peripheral surface. Then, the coil 8 is fixed to the core 7 using an adhesive or the like, and a fixed portion is produced.
The rotating shaft 4 is supported by the rolling bearing 11, the holding member 3 is attached to the base member 9 so as to be rotatable around the central axis O, and the galvano scanner 1 is assembled. The gap between the semi-cylindrical surface 3b of the holding member 3 and the inner peripheral surface of the core 7 is adjusted to about 0.5 mm.

Next, the operation of the galvano scanner 1 configured as described above will be described.
In the galvano scanner 1, the permanent magnet 5 is integrated with the holding member 3 so that the length direction is parallel to the central axis O, the outer peripheral surface is directed to the central axis O, and both side surfaces are flush with the semi-cylindrical surface 3 b. Is molded. Further, the magnetization orientation direction 6 of the permanent magnet 5 coincides with the circumferential direction of the circular arc cross section. Thereby, the permanent magnet 5 and the core 7 constitute a magnetic circuit M as indicated by an arrow in FIG. Therefore, the magnetic flux of the permanent magnet 5 passes through the linear part 8a of the coil 8 from one end of the permanent magnet 5 and enters the core 7, flows in the core 7 to the other side in the circumferential direction, and then the linear part 8b of the coil 8. And flows so as to return to the other side in the circumferential direction of the permanent magnet 5 through the air gap.

  Here, since the length directions of the straight portions 8a and 8b of the coil 8 disposed on the inner peripheral surface of the core 7 coincide with the axial direction of the core 7, the magnetic flux is coiled so as to be substantially orthogonal to the conducting wire. Interlink 8 Therefore, when a current is passed through the conducting wire of the coil 8, a Lorentz force is generated in a direction orthogonal to the direction of the current and the direction of the magnetic flux. And since the direction of the current in the straight portions 8a and 8b is opposite, the Lorentz force generated in the straight portions 8a and 8b becomes a force in the same direction around the central axis O. This Lorentz force acts as a driving torque of the holding member 3, and the holding member 3 (movable part) rotates around the central axis O. Then, by changing the direction of the current flowing through the conducting wire of the coil 8, the rotation direction of the holding member 3 (movable part) around the central axis O can be changed.

Next, laser processing using the galvano scanner 1 will be described.
First, two galvano scanners 1 for the X-axis direction and for the Y-axis direction are arranged in a laser beam path of a laser processing machine (not shown). The rotation angle of the reflection mirror 2 is controlled by a control circuit (not shown) based on the output of a rotary encoder (not shown) provided in each galvano scanner 1. Thereby, the reflection direction of the laser beam is changed, and the incident position of the laser beam on the workpiece is controlled.

  Taking the hole processing of the epoxy substrate as an example, the galvano scanner 1 repeats acceleration → deceleration → stationary → acceleration → deceleration..., While changing the irradiation position of the laser beam on the epoxy substrate. Open one by one in turn. In addition, the hole is machined while stationary. The current flowing through the coil 8 increases during acceleration, decreases during deceleration, and becomes zero when stationary. However, since the stationary time is short, the current waveform is a sine wave during continuous machining. The waveform is close to. In order for the control circuit to stably control the rotational position, the current waveform flowing through the coil 8 is mainly a sine wave and a harmonic of an N-times harmonic (N = 1, 2,...) Of the control frequency. The waveform is superimposed. For example, when drilling at a speed of 2,000 points / sec is performed at a control frequency of 100 kHz, the current waveform flowing through the coil 8 is a waveform in which a harmonic group of 100 × N kHz is superimposed on a sine wave of 2,000 Hz.

At this time, the Joule loss Wcu in the coil 8 is Wcu = R × I ^{2 where} R is the coil resistance and I is the effective current value. In addition, since the neodymium sintered magnet has high resistance but has conductivity, an eddy current corresponding to a change in magnetic flux generated by the current flowing in the coil 8 flows into the permanent magnet 5 and eddy current loss occurs. . Since these two losses increase in proportion to the magnitude of the current flowing through the coil 8, the losses increase during high acceleration.
Then, the cooling water is supplied from the inflow port 12 to the cooling water flow path 14, absorbs the heat transmitted from the permanent magnet 5 or the coil 8 to the base member 9, and is discharged from the discharge port 13.

  According to the first embodiment, since the magnetic path of the movable part is composed only of the permanent magnet 5, it is not necessary to produce the holding member 3 that is the main part of the movable part from a heavy magnetic material such as iron. That is, the holding member 3 can be made of a lightweight member such as a resin, the weight of the movable portion is reduced, and the inertia of the movable portion is reduced. Further, the volume of the permanent magnet 5 can be increased, and the amount of magnetic flux generated by the permanent magnet 5 can be increased. Therefore, the torque per inertia of the movable part can be increased without increasing the current flowing through the coil 8, and a high acceleration can be realized while suppressing the loss. And since loss is suppressed, the heat_generation | fever in the permanent magnet 5 or the coil 8 is suppressed, and the malfunction which deviates from the operating temperature range of an encoder, or the permanent magnet 5 carries out a heat demagnetization is avoided beforehand.

  The base member 9 is made of a good heat conductive material such as copper, and the cooling water flow path 14 is formed inside the base member 9. Therefore, since the heat generated by the permanent magnet 5 and the coil 8 is transmitted to the base member 9 and radiated to the cooling water flowing through the cooling water flow path 14, an excessive temperature rise of the permanent magnet 5 and the coil 8 can be suppressed. As a result, the current flowing through the coil 8 can be increased without increasing the temperature of the permanent magnet 5 or the coil 8, torque is increased, and acceleration is increased.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view showing the configuration of a galvano scanner according to Embodiment 2 of the present invention. In addition, a transverse sectional view is a sectional view in a plane orthogonal to the central axis O.

  In FIG. 4, permanent magnets 5 </ b> A are each made of a neodymium sintered magnet and have a first magnet body 21 formed in a rectangular column with an isosceles trapezoidal cross section, a length equal to that of the first magnet body 21, and parallel to each other. The second and third magnet bodies 22 and 23 are formed in a pseudo-trapezoidal prism having two sides, a hypotenuse and an arc side. The second and third magnet bodies 22 and 23 are flat in the same shape as the side surface of the first magnet body 21 formed of the hypotenuse having the isosceles trapezoidal cross section on one side face constituted by the hypotenuse of the pseudo trapezoidal section. On the surface, the other side surface constituted by the arc sides is formed into a curved surface having the same radius of curvature as the semi-cylindrical surface 3 b of the holding member 3. The magnetization orientation direction 6 of the first magnet body 21 is a direction parallel to two parallel sides of a trapezoidal cross section. The second magnet body 22 is parallel to two parallel sides of the cross-sectional pseudo trapezoid and is in a direction from the hypotenuse of the cross-section pseudo trapezoid to the arc side. The third magnet body 23 is parallel to two parallel sides of the pseudo-trapezoidal cross section and is directed in a direction from the arc side of the pseudo-trapezoidal cross section toward the oblique side.

  The 1st thru | or 3rd magnet bodies 21-23 have the bottom face comprised by the long side of the parallel parallel sides of the cross-section isosceles trapezoid of the 1st magnet body 21 toward the central axis O, and are the 2nd and 3rd magnets. The holding member 3 is insert-molded in a state where one side surface of the bodies 22 and 23 is abutted against both side surfaces of the first magnet body 21. The other side surfaces of the second and third magnet bodies 22 and 23 are flush with the semi-cylindrical surface 3 b of the holding member 3. The first magnet body 21 has a magnetization orientation direction 6 from the third magnet body 23 toward the second magnet body 22. Furthermore, the cross-sectional areas orthogonal to the magnetization orientation direction 6 of the first to third magnet bodies 21 to 23 are equal.

The permanent magnet 5A insert-molded in the holding member 3 in this way is symmetric with respect to a plane orthogonal to the central axis O at the center position in the direction of the central axis O of the holding member 3 and the semi-cylindrical surface of the holding member 3 It is symmetric with respect to a plane constituted by bisectors having a central angle of 3b.
The second embodiment is configured in the same manner as in the first embodiment except that the permanent magnet 5A is used instead of the permanent magnet 5.

The galvano scanner 1A configured as described above operates in the same manner as the galvano scanner 1 according to the first embodiment.
Therefore, the second embodiment also has the same effect as the first embodiment.
In the second embodiment, since the permanent magnet 5A is divided into three in the magnetic path direction, the path of the eddy current flowing inside the permanent magnet 5A is divided, and the eddy current loss is reduced.
Since the 1st thru | or 3rd magnet bodies 21-23 are produced by the square pillar of cross-section isosceles trapezoid or cross-section pseudo trapezoid, manufacture of the 1st thru | or 3rd magnet bodies 21-23 becomes easy.
In addition, since the magnetization orientation directions 6 of the first to third magnet bodies 21 to 23 are parallel to two parallel sides of the cross-section isosceles trapezoid or the cross-section pseudo trapezoid, the first to third magnet bodies 21 are provided. The magnetization orientation process of ˜23 becomes easy.

Embodiment 3 FIG.
FIG. 5 is a cross-sectional view showing a configuration of a galvano scanner according to Embodiment 3 of the present invention.

  In FIG. 5, permanent magnets 5 </ b> B are each made of a neodymium sintered magnet, and have a first magnet body 31 formed in a rectangular column with an isosceles trapezoidal cross section, and have a length equal to that of the first magnet body 31, and are opposed to each other. It is comprised from the 2nd thru | or 5th magnet bodies 32-35 formed in the square pillar of a cross-section pseudo-quadrangle which consists of a pair of side edge opposite to a base and a circular arc side. The magnetization orientation direction 6 of the first magnet body 21 is parallel to two parallel sides of the isosceles trapezoidal cross section and is directed from the other hypotenuse to one hypotenuse.

  The second and third magnet bodies 32 and 33 are configured by both bottom surfaces configured by the bottom sides of the cross-section pseudo-rectangle when the side surfaces configured by one side of the cross-section pseudo-rectangle are in contact with each other. The surface shape is the same shape as one side surface of the first magnet body 31 constituted by one oblique side of the isosceles trapezoidal cross section, and the surface shape constituted by both top surfaces constituted by the arc sides of the pseudo-quadratic section. The holding member 3 is formed in a curved surface having the same radius of curvature as the semi-cylindrical surface 3b of the holding member 3. In addition, the second and third magnet bodies 34 and 35 are formed such that the distance between the side surfaces formed by the two sides of the pseudo quadrangular cross section gradually decreases from the bottom surface to the top surface. Further, the magnetization orientation direction 6 of the second and third magnet bodies 32 and 33 is a direction parallel to the other side of the pseudoquadrangle in section and from the bottom toward the arc.

  The fourth and fifth magnet bodies 34 and 35 are configured by both bottom surfaces configured by the bottom sides of the cross-sectional pseudo-rectangle when the side surfaces configured by one side of the cross-sectional pseudo-rectangle are in contact with each other. The surface shape is the same shape as the other side surface of the first magnet body 31 composed of the other oblique side of the isosceles trapezoidal cross section, and the surface shape composed of both top surfaces composed of the arc sides of the pseudoquadrangle of the cross section. The holding member 3 is formed in a curved surface having the same radius of curvature as the semi-cylindrical surface 3b of the holding member 3. Further, the 42 and the fifth magnet bodies 34 and 35 are formed such that the distance between the side surfaces constituted by both sides of the pseudo-quadrangle is gradually narrowed from the bottom surface to the top surface. Further, the magnetization orientation direction 6 of the fourth and fifth magnet bodies 34 and 35 is a direction parallel to the other side of the pseudoquadrangle in section and from the arc side to the bottom side.

  The 1st thru | or 5th magnet bodies 31-35 turn the bottom face comprised by the long side of the parallel two sides of the isosceles trapezoid of the cross section of the 1st magnet body 31 to the central axis O, and are the 2nd and 3rd magnets. The side surfaces constituted by one side of the cross-sectional pseudo-rectangle of the bodies 32 and 33 are brought into close contact with each other, both bottom surfaces are butted against one side surface of the first magnet body 31, and the fourth and fifth magnet bodies 34 and 35 are further made. The holding member 3 is insert-molded in such a state that the side surfaces constituted by one side of the pseudo-quadrature of the cross section are brought into close contact with each other and both bottom surfaces are butted against the other side surface of the first magnet body 31. The top surfaces of the second to fifth magnet bodies 32 to 35 are flush with the semi-cylindrical surface 3b of the holding member 3.

The permanent magnet 5B insert-molded on the holding member 3 in this manner is symmetrical with respect to a plane orthogonal to the central axis O at the center position in the direction of the central axis O of the holding member 3 and the semi-cylindrical surface of the holding member 3 It is symmetric with respect to a plane constituted by bisectors having a central angle of 3b.
The third embodiment is configured in the same manner as in the second embodiment except that a permanent magnet 5B is used instead of the permanent magnet 5A.

The galvano scanner 1B configured as described above operates in the same manner as the galvano scanner 1A according to the second embodiment.
Therefore, the third embodiment also has the same effect as the second embodiment.
In the third embodiment, the magnetic path cross-sectional area of the magnet body pair of the second and third permanent magnets 32 and 33 arranged in contact with one side of the first magnet body 31 is directed toward the central axis O. It is getting bigger gradually. Similarly, the magnetic path cross-sectional area of the magnet body pair of the fourth and fifth permanent magnets 34 and 35 arranged in contact with the other side of the first magnet body 31 gradually increases toward the central axis O. Yes. As a result, the center of gravity of the permanent magnet 5B approaches the central axis O, and the inertia is reduced, so that the torque per inertia of the movable part can be increased and high acceleration can be easily obtained.

Embodiment 4 FIG.
FIG. 6 is a cross-sectional view showing the configuration of a galvano scanner according to Embodiment 4 of the present invention.

  In FIG. 6, each of the permanent magnets 5C is made of a neodymium sintered magnet, and is a first to fourth magnet body formed in a square column having a pseudo-quadrangle cross section composed of an opposing base and a pair of side edges opposing to an arc side. It is comprised from 41-44.

  When the first and second magnet bodies 41 and 42 are arranged so that side surfaces constituted by one side of the cross-section pseudo-rectangle are in contact with each other, both bottom surfaces constituted by the bottom sides of the cross-section pseudo-rectangle are orthogonal to each other, A surface shape formed by both top surfaces formed by arcuate sides of a pseudoquadrangle in cross section is formed on a curved surface having the same radius of curvature as the semi-cylindrical surface 3 b of the holding member 3. In addition, the first and second magnet bodies 41 and 42 are formed such that the distance between the side surfaces formed by the both sides of the pseudo-quadrangle is gradually narrowed from the bottom surface to the top surface. Furthermore, the magnetization orientation direction 6 of the first and second magnet bodies 41 and 42 is a direction parallel to the other side of the pseudoquadrangle in cross section and from the bottom toward the arc.

  When the third and fourth magnet bodies 43 and 44 are arranged so that side surfaces constituted by one side of the cross-section pseudo-rectangle are in contact with each other, both bottom surfaces constituted by the bottom sides of the cross-section pseudo-rectangle are orthogonal, A surface shape formed by both top surfaces formed by arcuate sides of a pseudoquadrangle in cross section is formed on a curved surface having the same radius of curvature as the semi-cylindrical surface 3 b of the holding member 3. In addition, the third and fourth magnet bodies 43 and 44 are formed such that the distance between the side surfaces constituted by both sides of the pseudo-quasi-cross section gradually decreases from the bottom surface to the top surface. Further, the magnetization orientation direction 6 of the third and fourth magnet bodies 43 and 44 is a direction parallel to the other side of the pseudoquadrangle in section and from the arc side to the bottom side.

  The 1st thru | or 4th magnet bodies 41-44 closely_contact | adhere the side surface comprised by one side of the cross-section pseudo-quadrangle of the 1st and 2nd magnet bodies 41 and 42, the 3rd and 4th magnet bodies 43, The holding member 3 is insert-molded in such a state that the side surfaces constituted by one side of the cross section pseudo-rectangular shape 44 are brought into close contact with each other and the bottom surfaces of the second and fourth magnet bodies 42 and 44 are in contact with each other. The top surfaces of the first to fourth magnet bodies 41 to 44 are flush with the semi-cylindrical surface 3b of the holding member 3. Furthermore, the bottom surfaces of the first and third magnet bodies 41 and 43 are flush with the mirror mounting surface 3a.

The permanent magnet 5 </ b> C insert-molded on the holding member 3 in this way is symmetric with respect to a plane perpendicular to the central axis O at the center position in the direction of the central axis O of the holding member 3, and the semi-cylindrical surface of the holding member 3. It is symmetric with respect to a plane constituted by bisectors having a central angle of 3b.
The fourth embodiment is configured in the same manner as in the third embodiment except that a permanent magnet 5C is used instead of the permanent magnet 5B.

The galvano scanner 1C configured as described above operates in the same manner as the galvano scanner 1B according to the third embodiment.
Therefore, this fourth embodiment also has the same effect as the third embodiment.
In the fourth embodiment, since the permanent magnet 5C is constituted by the first to fourth magnet bodies 41 to 44, the number of magnet bodies can be reduced and the assemblability can be reduced as compared with the third embodiment. Can be improved.

In each of the above embodiments, a reflection mirror is used as the optical member. However, the optical member is not limited to the reflection mirror, and may be a diffraction grating, for example. In this case, the diffraction grating is held by the holding member so that the central axis O is located on the polarization plane.
Moreover, in each said embodiment, although the core shall be produced with the powder iron core, the core should just be produced with the magnetic material, for example, the laminated iron core formed by laminating | stacking and integrating a magnetic steel plate may be sufficient.

  In each of the above embodiments, the back surface of the holding member, the inner peripheral surface of the core, and the like are gathered in the axial direction of the central axis with an arc having a central angle of 180 °, with the center aligned with the central axis. However, the back surface of the holding member, the inner peripheral surface of the core, and the like are not necessarily a semi-cylindrical surface (arc surface). For example, the central angle is 160 ° or 200 °. May be a circular arc surface formed by gathering the centers thereof in the axial direction of the central axis so that the center coincides with the central axis.

Further, in each of the embodiments described above, the movable part is rotatably supported by the rolling bearing provided on the base member. However, the bearing is not limited to the rolling bearing, and the movable part is the center. What is necessary is just to be supported by the base member so that rotation around the axis | shaft O is possible, for example, an air bearing may be sufficient.
In each of the above embodiments, the coil is disposed on the inner peripheral surface of the core. However, a coil storage recess is provided on the inner peripheral surface of the core, and the coil is stored in the coil storage recess. You may make it do.
Moreover, in each said embodiment, although the permanent magnet shall be produced with the neodymium sintered magnet, a permanent magnet does not need to be limited to a neodymium sintered magnet, For example, a samarium type sintered magnet may be sufficient.

  1, 1A, 1B, 1C Galvano scanner, 2 reflection mirror (optical member), 3 holding member (movable part), 3b semi-cylindrical surface (arc surface), 5, 5A, 5B, 5C permanent magnet (movable part), 7 Core, 8 coils, O center axis.

Claims (4)

In a galvano scanner that rotates or drives an optical member to reflect or diffract polarized light,
A holding member that holds the optical member such that the back surface is an arc surface, and the central axis of the arc surface is positioned on the anti-slope or polarization surface of the optical member;
A permanent magnet provided integrally with the holding member and constituting a movable part together with the holding member;
A base member that rotatably supports the holding member around the central axis;
A core disposed on the base member so as to face the arc surface of the holding member;
A coil that is fixed to the core and that drives the holding member to rotate about the central axis in cooperation with the permanent magnet;
A galvano scanner, wherein the holding member is made of a non-magnetic resin material, and the magnetic path of the movable part is composed only of the permanent magnet.   The galvano scanner according to claim 1, wherein the permanent magnet is divided into a plurality of magnet bodies.   2. The permanent magnet according to claim 1, wherein a magnet cross-sectional area perpendicular to the magnetization orientation direction on the arc surface side is smaller than a magnet cross-sectional area perpendicular to the magnetization orientation direction on the central axis side. Alternatively, the galvano scanner according to claim 2.   The galvano scanner according to any one of claims 1 to 3, wherein the permanent magnet is insert-molded in the holding member.

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