JP4727509B2 - Beam scanner - Google Patents

Description

  The present invention relates to a beam scanner including a mirror capable of reflecting and scanning an incident beam.

  In the field related to semiconductors and electronic components, high-density mounting of high-throughput, high-density components is required for realizing miniaturization and high functionality of information communication terminals such as electronic devices such as mobile phones. There is a need for a system for drilling a substrate.

  When processing is performed by irradiating a laser beam, high-speed processing is possible by using a galvano scanner (beam scanner) that reflects and scans the beam with a galvano mirror (rotating mirror). Become.

  Therefore, in order to realize high speed, high accuracy, and high throughput of laser processing, there is an increasing demand for a galvano scanner that is a key component of a laser processing apparatus.

  FIG. 5 is a schematic diagram of a laser processing apparatus including a galvano scanner. The laser processing apparatus includes a laser oscillator 12, a first galvano scanner 20, a second galvano scanner 24, an fθ lens 6, and a stage 8. The first and second galvano scanners 20 and 24 include rotating mirrors 20a and 24a, respectively. As shown in the figure, when the XYZ orthogonal coordinate system is defined, the rotating mirror 20a of the first galvano scanner 20 rotates, for example, around an axis parallel to the Z axis, and the rotating mirror 24a of the second galvano scanner 24 is, for example, Y Rotate around an axis parallel to the axis.

  The laser oscillator 12 emits a pulse laser beam 14 in a direction parallel to the XY plane, for example. The emitted pulse laser beam 14 is reflected by the rotary mirror 20a of the first galvano scanner 20 in a predetermined direction parallel to the XY plane. The pulse laser beam 14 is further reflected in a predetermined direction by the rotating mirror 24 a of the second galvano scanner 24, passes through the fθ lens 6, and irradiates the workpiece 10 placed on the stage 8. The pulse laser beam 14 is deflected by the fθ lens 6 in a direction perpendicular to the surface of the workpiece 10 and is incident on the workpiece 10.

  The laser beam 14 scans the workpiece 10 by rotating the rotating mirrors 20a, 24a of the first and second galvano scanners 20, 24 and changing the traveling direction of the laser beam 14.

  FIG. 6 is a cross-sectional view schematically showing the moving coil type galvano scanner. The galvano scanner has a rotating mirror 33 that reflects incident light, a rotating shaft 30 that holds the rotating mirror 33 at the tip and rotates around it, first and second bearings 31 and 32 that rotatably support the rotating shaft 30, and rotation. A coil 34 fixed to the shaft 30, a permanent magnet 35 and a yoke 36 that generate torque for rotating the rotating mirror 33 when a current is passed through the coil 34, and an angle sensor for detecting the rotation angle of the rotating mirror 33. 37.

  Torque generated when a current is passed through the coil 34 disposed in the magnetic field formed by the permanent magnet 35 and the yoke 36 is transmitted to the rotary shaft 30 supported by the first and second bearings 31 and 32. Then, the rotating mirror 33 is rotated. The rotation angle of the rotating mirror 33 is measured by an angle sensor 37 attached to the end of the rotating shaft 30 opposite to the rotating mirror 33.

  As described above, there is an increasing demand for high-speed and high-precision driving of galvano scanners. However, in the galvano scanner shown in FIG. 6, since the rotary mirror 33, the coil 34, and the angle sensor 37 are arranged in series with the rotary shaft 30, resonance due to torsional deformation of the rotary shaft 30 is likely to occur. In particular, the rotating mirror 33 and the angle sensor 37 attached to both ends of the rotating shaft 30 are the main causes of the resonance phenomenon due to the torsional deformation of the rotating shaft 30 and hinder the high-speed driving of the rotating mirror 33.

  Further, when torsional deformation occurs on the rotating shaft 30, there is a case where a deviation occurs between the actual rotation angle of the rotating mirror 33 and the measured value by the angle sensor 37, and the positioning accuracy of the laser irradiation position may be lowered.

  In order to solve such problems, a configuration in which a rotating mirror is not arranged in series at the end of the rotating shaft has been proposed (see, for example, Patent Documents 1, 2, and 3). Patent Document 1 discloses a galvanomirror device having a configuration in which a coil is directly attached to the back surface of a mirror. Patent Documents 2 and 3 disclose configurations in which coils are arranged at both ends of a mirror (mirror type optical path deflecting device and scanner device, respectively).

  These configurations are effective when a mechanism for rotating a small mirror is constructed in a compact manner. However, since the moment of inertia becomes large, it is not easy to generate a torque sufficient for driving when the mirror is large, and it is not suitable for high-speed and high-precision driving.

  In particular, in the configuration in which the coil is directly attached to the mirror, the heat generated by the coil is easily transmitted to the mirror, and as a result, the cross-sectional shape of the laser beam reflected by the mirror may be deteriorated and the positioning accuracy may be lowered. . For this reason, there is a problem that a current sufficient for high-speed driving cannot be supplied. Furthermore, since the heat generated in the coil reduces the rigidity of the coil, resonance is likely to occur in the movable part, making it difficult to achieve high speed and high accuracy.

  The moving coil galvano scanner has a configuration in which a coil is disposed on a rotor and a permanent magnet is disposed on a stator. On the other hand, a moving magnet type galvano scanner having a configuration in which a permanent magnet is disposed on a rotor and a coil is disposed on a stator is also known (see, for example, Patent Document 4).

  The galvano scanner (galvano mirror actuator) described in Patent Document 4 has a configuration in which a permanent magnet is disposed on the back surface of a mirror frame that holds a mirror. According to this configuration, conduction of heat generated in the coil to the mirror can be prevented. However, when the mirror is large, it is not easy to generate a torque sufficient for driving.

  A large torque can be obtained by increasing the number of turns of the coil. However, in this case, the coil gap also becomes thick, the permeance coefficient becomes small, and demagnetization occurs in the permanent magnet. In addition, the amount of heat generated in the coil increases. For this reason, increasing the number of turns of the coil cannot be said to meet the demand for high speed and high precision driving.

Japanese Patent Laid-Open No. 7-104207 JP-A-6-331909 JP 2003-43405 A JP 2000-81588 A

  An object of the present invention is to provide a beam scanner capable of operating at high speed.

  Another object of the present invention is to provide a beam scanner capable of operating with high accuracy.

  It is another object of the present invention to provide a beam scanner capable of stable operation.

According to an aspect of the present invention, a fixed base, a bearing holder fixed to the fixed base, a rotating shaft rotatably supported by the bearing holder, and a circumferential direction of a side surface of the rotating shaft are provided. A yoke arranged to face the region of the portion and fixed to the fixed base, protruding from the surface facing the side surface of the rotating shaft toward the rotating shaft, and between the side surface of the rotating shaft A yoke that includes a pair of magnetic poles that are arranged to define a gap and are arranged in the rotation direction of the rotation axis; and a reflector that is fixed on a surface of the rotation axis that is formed along the length direction; When the rotating shaft is stationary at a neutral position with respect to the rotating direction, a plurality of the rotating shafts fixed to the side facing the yoke side and arranged in the rotating direction and magnetized in the radial direction of the rotating shaft Of permanent magnets and wound around the magnetic poles And the pair of magnetic poles are arranged so as to have a symmetric relationship with respect to a neutral plane including a virtual straight line serving as a rotation center of the rotation shaft, and the plurality of permanent magnets and their polar orientations Are arranged so as to have a symmetrical relationship with respect to the neutral plane when the rotating shaft is stationary at the neutral position, and a plurality of permanent magnets are fixed on the same side with respect to the neutral plane. The permanent magnets adjacent to each other on the same side with respect to the neutral plane are arranged so that the radial polarities of the rotating shafts are opposite to each other, and the coil is symmetrical with respect to the neutral plane. There is provided a beam scanner in which the rotating shaft side end of the magnetic pole arranged at a position is wound so as to be excited to the opposite polarity.
According to another aspect of the present invention, a fixed base, a bearing holder fixed to the fixed base, a rotating shaft rotatably supported by the bearing holder, and a peripheral surface of a side surface of the rotating shaft are provided. A yoke arranged to face a part of the region with respect to the direction and fixed to the fixed base, protruding from the surface facing the side surface of the rotating shaft toward the rotating shaft, and a side surface of the rotating shaft; And a yoke including a pair of magnetic poles arranged so as to be aligned in the rotation direction of the rotating shaft, and a reflection fixed on a surface formed along the length direction of the rotating shaft When the mirror and the rotating shaft are stationary in a neutral position with respect to the rotating direction, they are fixed to the side surface of the rotating shaft facing the yoke side, and are arranged so as to be aligned in the rotating direction, and are magnetized in the radial direction of the rotating shaft. a pair of permanent magnets, the pole And a His coil, said pair of magnetic poles, said as a rotation center of the rotation shaft includes a virtual straight line are arranged symmetrically in relation with respect to the neutral plane and the pair of permanent magnets, and the polarity Are arranged so as to have a symmetric relationship with respect to the neutral plane when the rotating shaft is stationary at the neutral position, and the coil is arranged in a symmetric position with respect to the neutral plane. wherein and end of the rotating shaft side is wound to be energized in the opposite polarity, addition, when the rotating shaft is stationary in the neutral position with respect to the rotational direction, so as to be symmetrical relationship with respect to the neutral plane in the and pair of salient poles on the side surface of the rotary shaft is formed, when the rotating shaft is stationary in the neutral position, the magnetic poles, with respect to the rotational direction, spanning said and said permanent magnet salient position, Other beam scanner is disposed between the permanent magnet salient is provided.

  This beam scanner is a beam scanner having high speed, high accuracy, and stability in operation.

  According to the present invention, it is possible to provide a beam scanner capable of operating at high speed.

  Further, it is possible to provide a beam scanner that can operate with high accuracy.

  Furthermore, a beam scanner capable of stable operation can be provided.

  1A to 1C are schematic cross-sectional views showing a galvano scanner according to the first embodiment.

  Reference is made to FIG. The galvano scanner according to the first embodiment is made of a magnetic material, and a swing axis C penetrating the inside in the length direction is defined. A shaft 52 that can rotate (rotate) around the swing axis C, A flat mirror 51 that is attached to the upper portion in the radial direction (on the light incident side) and reflects incident light, a salient pole-shaped yoke 62 made of a magnetic material, and a coil 61 are included.

  As shown in the following figure, a permanent magnet is fixed to the side surface of the shaft 52, and a power source (a torque generating source for generating a driving torque for rotating the shaft 52) is provided together with the salient pole yoke 62 and the coil 61. Constitute.

  The coil 61 is disposed on the salient pole type yoke 62, and the salient pole type yoke 62 is fixed to the fixed base 65. The fixed base 65 defines a fixed reference position of the galvano scanner according to the embodiment.

  The shaft 52 oscillates (rotates) around the oscillating axis C at two points separated along the length direction by bearing holders 64a and 64b fixed to the fixed base 65 via bearings 54a and 54b. It is supported freely.

  A stopper 55 is attached to one end of the shaft 52 in the length direction. The rotation range of the shaft 52 can be limited by the stopper 55 and the stopper holder 63 fixed to the bearing holder 64a.

  The galvano scanner also includes an angle sensor 42. The angle sensor 42 is indirectly fixed to the scale 42a fixed to the end of the shaft 52 opposite to the end to which the stopper 55 is attached, and to the fixed base 65 (position with respect to the fixed base 65). The encoder head 42b is included. An origin position is defined on the scale 42a. The encoder head 42b can detect the rotational position of the mirror 51 by reading the displacement of the origin position accompanying the swing of the scale 42a.

  FIG. 1B is a cross-sectional view taken along line 1B-1B in FIG.

  The vicinity of the center in the length direction of the shaft 52 has a shape in which, for example, a part of a cylinder is cut along the central axis (oscillation axis C) so that the cut surface becomes a plane. Therefore, the cross section of the shaft 52 at this position has a shape obtained by cutting a part of an arc from a circle into a chord shape. The mirror 51 is directly fixed on the cut plane portion of the shaft 52.

  Permanent magnets 53a to 53d having the same shape and the same characteristics are fixed to the cylindrical side surface of the shaft 52. The permanent magnets 53a to 53d are permanent magnets that are arranged in the rotational direction of the shaft 52 and are magnetized in the radial direction of the shaft 52.

  In the permanent magnets 53 a and 53 b, the S pole and the N pole are arranged in the same direction in the radial direction of the shaft 52. For example, the N pole is disposed on the shaft 52 side and the S pole is disposed on the salient pole yoke 62 side (slots 66a and 66b side).

  The permanent magnets 53 c and 53 d are also arranged in the same direction with respect to the radial direction of the shaft 52. Further, in the permanent magnets 53 a and 53 c, the S pole and the N pole are opposite to each other in the radial direction of the shaft 52. Therefore, for example, the permanent magnets 53c and 53d are arranged with the S pole facing the shaft 52 and the N pole facing the salient pole yoke 62 (slots 66a and 66b).

  The permanent magnets 53a to 53d are formed in parallel to the central axis (swing axis C) of the shaft 52. The permanent magnets 53 a and 53 b include a virtual plane P that includes the central axis (swing axis C) of the shaft 52 and intersects the plane mirror 51 perpendicularly (the virtual plane P is fixed to the shaft 52, and together with the shaft 52. It is a virtual plane that swings around the swing axis C). The same applies to the permanent magnets 53c and 53d.

  That is, the permanent magnets 53 a to 53 d and the direction of the polarity thereof are arranged so as to have a symmetrical relationship with respect to the virtual plane P.

  Furthermore, the permanent magnets 53a and 53c include a virtual plane Q (the virtual plane Q is also fixed to the shaft 52 and includes the central axis (swing axis C) of the shaft 52 and intersects with the virtual plane P perpendicularly. 52 is a virtual plane that swings around the swing axis C together with 52). The permanent magnets 53b and 53d are also arranged symmetrically with respect to the virtual plane Q.

  The plane mirror 51 and the shaft 52 are also self-symmetric with respect to the virtual plane P.

  As shown, an XYZ coordinate system is defined. When the vertical direction is the Z direction and the fixed base 65 is disposed in a plane parallel to the XY plane, the shaft 52 is disposed such that the central axis (swing axis C) is parallel to the Y direction.

  The salient pole yoke 62 is disposed so as to face a part of the side surface of the shaft 52 in the circumferential direction. The salient pole yoke 62 is formed with slots 66a and 66b which are convex portions protruding toward the shaft 52 side (permanent magnets 53a to 53d side). For example, the slots 66a and b are identical to each other. Slots 66 a and b define a gap between the sides of shaft 52.

  The slots 66a and b are formed, for example, parallel to the Y axis, that is, parallel to the swing axis C. Further, they are arranged so as to have a symmetrical relationship with respect to a plane including the swing axis C and parallel to the YZ plane (neutral plane, a plane that coincides with the virtual plane P in FIG. 1B). For example, the salient pole yoke 62 itself is self-symmetric with respect to the neutral plane.

  Coils 61a and 61b are wound around the slots 66a and 66b, respectively.

  As described above, in the galvano scanner according to the embodiment, the mirror 51 is directly fixed to the shaft 52. When the mirror 51 is attached to the shaft 52, for example, a mirror frame that holds the mirror 51 is not used, so that the rigidity can be increased. Thereby, resonance due to bending deformation of the mirror 51 and resonance due to torsional deformation of the shaft 52 can be suppressed, and the mirror 51 can be positioned with high speed and high accuracy.

  The coils 61a and 61b are disposed in the yoke 62 (slots 66a and 66b) and are not disposed on the shaft 52 side. Therefore, it is possible to prevent the deterioration of the shape of the laser beam (the laser beam reflected by the mirror 51) and the decrease in positioning accuracy caused by the heat generated in the coils 61a and 61b being conducted to the mirror 51.

  The structure and operation of the power source will be described with reference to FIG. This figure shows a state in which the shaft 52 is stationary with respect to the rotational direction at an equilibrium position (neutral position) when the coil is not energized and the magnetic force of the permanent magnets 53a to 53d is not considered.

  The permanent magnets 53a to 53d are fixed to the side surface of the shaft 52 facing the salient pole yoke 62 side, and are arranged so as to be symmetrical with respect to the neutral plane. The cross-sectional shapes of the permanent magnets 53a to 53d are, for example, all shapes obtained by removing the shaft 52 from the sector shape centered on the swing axis C.

  The center lines of the slots 66a and b of the salient pole yoke 62 extend toward the swing axis C along the X-axis positive direction and the negative direction, respectively.

  The ends of the slots 66 a and b on the shaft 52 side are disposed between two permanent magnets adjacent to each other in the rotation direction of the shaft 52. In the first embodiment, the slot 66a is disposed between the permanent magnets 53a and 53c, and the slot 66b is disposed between the permanent magnets 53b and 53d.

  When four or more permanent magnets are arranged, the end of the slot on the shaft side is, for example, arranged on the same side with respect to the virtual plane P, and between two permanent magnets adjacent to each other with respect to the rotation direction of the shaft 52. Be placed.

  In the slots 66a and b, coils 61a and 61b are formed with the same number of turns, respectively, by a single continuous wire. The coil is wound such that the ends of the slots 66a and 66b on the shaft 52 side (the end of the slot) are excited with opposite polarities. The winding direction of the coil 61a and the coil 61b is opposite.

  For example, when a current is passed along the “current direction” arrow in the figure, an N pole is formed at the end of the slot 66a on the side of the shaft 52 (swing axis C), and a shaft 52 (swinging) is provided for the slot 66b. An S pole is formed at the end of the moving axis C).

  In this figure, the lines of magnetic force formed in the galvano scanner are shown with an arrow on the closed curve. A magnetic circuit is formed in the direction of the permanent magnet 53d, the slot 66b (coil 61b), the salient pole yoke 62, the slot 66a (coil 61a), the permanent magnet 53a, the shaft 52, and the permanent magnet 53d.

  In the state where the magnetic poles are formed as shown in the figure, an attractive force is applied between the permanent magnet 53a and the slot 66a, and a repulsive force is applied between the permanent magnet 53c and the slot 66a. An attractive force acts between the permanent magnet 53d and the slot 66b, and a repulsive force acts between the permanent magnet 53b and the slot 66b.

  Rotational torque (in the case shown in the figure) that swings the movable part (the shaft 52, the mirror 51, the permanent magnets 53a to 53d, and the scale 42a) around the swing axis C by these attractive force and repulsive force. Torque in the counterclockwise direction).

  FIG. 2 is a schematic sectional view showing the vicinity of the power source of the galvano scanner according to the second embodiment, and corresponds to FIG. The galvano scanner according to the second embodiment is characteristically different from the galvano scanner according to the first embodiment in the configuration of the shaft 52. This figure shows a state where the shaft 52 is stationary with respect to the rotation direction at an equilibrium position (neutral position) when the coil is not energized and the magnetic force of the permanent magnets 53a and 53b is not taken into consideration.

  In the second embodiment, two salient poles 56 a and 56 b are formed on the shaft 52.

  The salient poles 56a and 56b are convex portions formed of a magnetic material on the cylindrical side surface of the shaft 52 and projecting toward the salient pole yoke 62 side (slots 66a and 66b side). For example, the salient poles 56a and 56b are identical to each other and define a gap between the salient pole yoke 62 (slots 66a and 66b).

  The salient poles 56a and 56b are arranged so as to have a symmetrical relationship with respect to the neutral plane. For example, as shown in the drawing, one of the side surfaces of the salient pole 56a along the Y direction is on the virtual plane Q, and the other is on the mirror 51 side. The same applies to the salient pole 56b.

  In the first embodiment, the four permanent magnets 53a to 53d are fixed to the cylindrical side surface of the shaft 52. However, in the second embodiment, the two permanent magnets 53a and 53b are fixed to the cylindrical side surface of the shaft 52. Fixed.

  The permanent magnets 53a and 53b in the second embodiment correspond to the permanent magnets 53c and 53d in the first embodiment, respectively, and the basic configurations are the same. However, as shown in the figure, one of the side surfaces of the permanent magnet 53a along the Y direction is on the imaginary plane Q, and the other side is disposed on the side opposite to the mirror 51 (the salient pole yoke 62 side). Different in. The same applies to the permanent magnet 53b.

  In the form shown in FIG. 2, the permanent magnet 53a and the salient pole 56a are adjacent to each other, and the slot 66a is disposed at a position across the both. An air gap may be provided between the permanent magnet 53a and the salient pole 56a, and the slot 66a may be disposed at a position across the both. Further, a gap may be provided between the permanent magnet 53a and the salient pole 56a, and the slot 66a may be disposed between the two. The same applies to the relationship between the permanent magnet 53b, the salient pole 56b, and the slot 66b.

  When a current is passed through the coils 61a and 61b wound around the slots 66a and 66b along the arrows in the “current direction” in the figure, the slot 66a has an N pole at the end on the shaft 52 (oscillation axis C) side. In the slot 66b, an S pole is formed at the end of the shaft 52 (swing axis C). Accordingly, a magnetic circuit is formed in the direction of the permanent magnet 53b, the slot 66b (coil 61b), the salient pole yoke 62, the slot 66a (coil 61a), the salient pole 56a, the shaft 52, and the permanent magnet 53b.

  Due to the attractive force acting between the permanent magnet 53b and the slot 66b and the force with which the salient pole 56a and the slot 66a are arranged in a straight line, the movable part rotates counterclockwise around the swing axis C. .

  Since the galvano scanner according to the first and second embodiments uses the attractive force of the permanent magnet, it is possible to generate a large torque sufficient for high-speed driving of the large mirror. Further, the resonance due to the bending deformation of the mirror and the torsional deformation of the shaft can be suppressed, and the mirror can be positioned stably at high speed. Further, the amount of heat generated by the coil is small, and demagnetization of the permanent magnet is unlikely to occur. The galvano scanner according to the embodiment can realize high-speed and high-precision operation even when a large mirror is used.

  FIG. 3 is a graph showing output torque characteristics of the galvano scanners according to the first and second embodiments.

  The horizontal axis of the graph represents the rotation angle from the 0 ° position in the unit “degree (°)”, and the vertical axis represents the relative output torque in the unit “%”. Here, the 0 ° position means a position at which the virtual plane P coincides with the neutral plane, as shown in FIGS.

  The angle formed by the neutral plane and the virtual plane P when the movable part swings was defined as the rotation angle. In FIG. 1C and FIG. 2, when the virtual plane P is rotated counterclockwise from the 0 ° position, the rotation angle is defined as positive, and when rotated in the clockwise direction, the rotation angle is defined as negative. .

  Curve a shows the relationship between the rotation angle and output torque for the galvano scanner according to the first embodiment, and curve b shows the relationship between the galvano scanner according to the second embodiment.

  The galvano scanner according to the first embodiment (curve a) has a smaller torque fluctuation than the galvano scanner according to the second embodiment (curve b), and judging from only the graph shown in FIG. It can be seen that it is easy to achieve highly accurate and stable driving.

  FIG. 4 is a graph showing the cogging torque characteristics of the galvano scanner according to the first and second embodiments.

  The meaning of the horizontal axis of the graph is the same as in FIG. The vertical axis represents the relative cogging torque in the unit “%”. In FIG. 1C and FIG. 2, the cogging torque for rotating the shaft (virtual plane) counterclockwise is defined as positive, and the cogging torque for rotating clockwise is defined as negative.

  Curve c shows the relationship between the rotation angle and the cogging torque for the galvano scanner according to the first embodiment, and curve d shows the relationship between the galvano scanner according to the second embodiment. The graph was created with zero (non-energized) current flowing through the coil.

  In both the first and second embodiments, the galvano scanner (curve c) according to the first embodiment has a small cogging torque value. In addition, in both examples (curve c and curve d), the curve is downwardly inclined at the 0 ° position, and the cogging torque is movable even when the movable portion is tilted from the 0 ° position. It can be seen that it works in the direction of pulling the part back to the 0 ° position. Therefore, the galvano scanner according to the embodiment is a highly stable galvano scanner. For this reason, when the galvano scanner according to the embodiment is used, positioning control can be performed with high accuracy.

  The galvano scanner according to the embodiment can obtain a large torque sufficient for high-speed driving of a large mirror. Further, even when a large mirror is used, high speed, high accuracy, and highly stable driving can be realized.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

  It can be used in general for laser processing and laser processing apparatus. In particular, the present invention is suitably used for laser processing such as laser drilling and laser marking, and an apparatus for performing such laser processing, which require high-speed, high-accuracy and highly stable beam scanning. Further, it is used in laser processing and laser processing apparatus in which a large mirror is suitably used.

(A)-(C) are schematic sectional drawings which show the galvano scanner by a 1st Example. It is a schematic sectional drawing which shows the motive power source vicinity of the galvano scanner by a 2nd Example, and is a figure corresponding to FIG.1 (C). It is a graph which shows the output torque characteristic of the galvano scanner by the 1st and 2nd Example. It is a graph which shows the cogging torque characteristic of the galvano scanner by the 1st and 2nd Example. It is the schematic of the laser processing apparatus containing a galvano scanner. It is sectional drawing which shows the outline of a moving coil type galvano scanner.

Explanation of symbols

6 fθ lens 8 stage 10 workpiece 12 laser oscillator 14 laser beam 20 first galvano scanner 20a rotating mirror 24 second galvano scanner 24a rotating mirror 30 rotating shaft 31 first bearing 32 second bearing 33 rotating mirror 34 coil 35 permanent magnet 36 Yoke 37 Angle sensor 42 Angle sensor 42a Scale 42b Encoder head 51 Mirror 52 Shaft 53a-d Permanent magnet 54a, b Bearing 55 Stopper 56a, b Salient pole 61, 61a, b Coil 62 Salient pole type yoke 63 Stopper holder 64a, b Bearing holder 65 Fixed base 66a, b Slot C Oscillating shaft P, Q Virtual plane

Claims (3)

A fixed base and a bearing holder fixed to the fixed base;
A rotating shaft rotatably supported by the bearing holder;
A yoke that is disposed so as to face a part of the side surface of the rotating shaft in the circumferential direction and is fixed to the fixed base, from the surface facing the side surface of the rotating shaft toward the rotating shaft A yoke including a pair of magnetic poles protruding and defining a gap with a side surface of the rotation shaft and arranged to be aligned in a rotation direction of the rotation shaft;
A reflecting mirror fixed on a surface of the rotating shaft formed along the length direction;
When the rotating shaft is stationary at a neutral position with respect to the rotating direction, a plurality of the rotating shafts fixed to the side facing the yoke side and arranged in the rotating direction and magnetized in the radial direction of the rotating shaft With permanent magnets,
A coil wound around the magnetic pole,
The pair of magnetic poles are arranged so as to have a symmetric relationship with respect to a neutral plane including a virtual straight line serving as a rotation center of the rotation axis,
The plurality of permanent magnets and the directions of their polarities are arranged so as to have a symmetrical relationship with respect to the neutral plane when the rotation axis is stationary at the neutral position, and are the same with respect to the neutral plane A plurality of permanent magnets are fixed on the side, and the permanent magnets adjacent to each other on the same side with respect to the neutral plane are arranged so that the polarities in the radial direction of the rotating shaft are opposite to each other. ,
The coil is a beam scanner in which the coil is wound such that the end on the rotating shaft side of the magnetic pole arranged at a symmetric position with respect to the neutral plane is excited to the opposite polarity.   4 or more of the permanent magnets are arranged, and when the rotating shaft is stationary at a neutral position, they are arranged on the same side with respect to the neutral plane, and are adjacent to each other with respect to the rotation direction of the rotating shaft. The beam scanner according to claim 1, wherein the magnetic pole is disposed between two permanent magnets. A fixed base and a bearing holder fixed to the fixed base;
A rotating shaft rotatably supported by the bearing holder;
A yoke that is disposed so as to face a part of the side surface of the rotating shaft in the circumferential direction and is fixed to the fixed base, from the surface facing the side surface of the rotating shaft toward the rotating shaft A yoke including a pair of magnetic poles protruding and defining a gap with a side surface of the rotation shaft and arranged to be aligned in a rotation direction of the rotation shaft;
A reflecting mirror fixed on a surface of the rotating shaft formed along the length direction;
When the rotating shaft is stationary at a neutral position with respect to the rotating direction, a pair of the rotating shaft fixed to the side surface facing the yoke side and arranged in the rotating direction and magnetized in the radial direction of the rotating shaft With permanent magnets ,
A coil wound around the magnetic pole,
The pair of magnetic poles are arranged so as to have a symmetric relationship with respect to a neutral plane including a virtual straight line serving as a rotation center of the rotation axis,
The pair of permanent magnets and the direction of the polarity thereof are arranged so as to have a symmetrical relationship with respect to the neutral plane when the rotating shaft is stationary at a neutral position.
The coil is wound so that the end on the rotating shaft side of the magnetic pole disposed at a symmetric position with respect to the neutral plane is excited to the opposite polarity ,
Furthermore, when the rotating shaft is stationary at a neutral position with respect to the rotation direction, a pair of convex poles is formed on the side surface of the rotating shaft so as to have a symmetrical relationship with respect to the neutral plane,
When the rotary shaft is stationary in the neutral position, the magnetic poles, with respect to the rotational direction, is disposed at a position spanning said and said permanent magnet salient, or between said permanent magnet salient Beam scanner.

Images