Galvano scanner and laser processing machine

Abstract

A galvano scanner (20) comprises: a galvano mirror (21) that has a dome-shaped curved mirror surface; and a drive unit (22) that has a flat surface (23) on which the galvano mirror (21) is mounted, and that causes translational movement of the galvano mirror (21) in a direction parallel to the flat surface (23). The drive unit (22) is provided with an α-axis direction drive unit (22α) that moves the galvano mirror (21) in an α-axis direction which is a direction parallel to the flat surface (23), and a β-axis direction drive unit (22β) that moves the galvano mirror (21) in a β-axis direction which is a direction parallel to the flat surface (23) and different from the α-axis direction.

Description

Galvano scanner and laser processing machine

[0001] The present disclosure relates to a galvanometer scanner and a laser processing machine equipped with the galvanometer scanner.

[0002] In recent years, the growing need for higher speeds and higher accuracy in laser processing has led to a demand for faster drive speeds for galvanometer scanners and higher accuracy in scan positioning. In galvanometer scanners that change the reflection direction of laser light by rotating a shaft supporting a planar galvanometer mirror, as the drive speed of the galvanometer scanner increases, the vibration characteristics inherent to the galvanometer mirror tend to cause surface tilt vibration of the galvanometer mirror, resulting in a larger deviation in the scanning position of the laser light and a deterioration in processing accuracy. Patent Document 1 discloses a galvanometer scanner in which one end of the planar galvanometer mirror is fastened to a motor and the other end is supported to form a double-end support structure, thereby suppressing surface tilt vibration and achieving both faster drive speeds and improved scan positioning accuracy.

[0003] Patent No. 6587603

[0004] When the driving speed of the galvanometer scanner increases, not only the surface tilt vibration of the galvanometer mirror but also the torsional vibration of the galvanometer mirror occurs. However, with the structure of the galvanometer scanner disclosed in Patent Document 1, it is difficult to suppress the torsional vibration of the galvanometer mirror, and therefore there is a problem that it is not possible to suppress the deterioration of processing accuracy due to the torsional vibration.

[0005] The present disclosure has been made in view of the above, and has an object to provide a galvano scanner that achieves both high-speed driving and improved scanning positioning accuracy.

[0006] In order to solve the above-mentioned problems and achieve the object, the galvanometer scanner of the present disclosure is characterized by comprising a galvanometer mirror having a dome-shaped curved mirror surface, and a drive unit having a flat surface on which the galvanometer mirror is placed and which translates the galvanometer mirror in a direction parallel to the flat surface.

[0007] The galvano scanner according to the present disclosure has the effect of achieving both high-speed driving and improved scanning positioning accuracy.

[0008] FIG. 1 is a diagram showing the configuration of a laser processing machine according to a first embodiment; FIG. 2 is a perspective view of a galvanometer scanner according to a first embodiment; FIG. 3 is a diagram showing the configuration of a control device according to a first embodiment; FIG. 4 is a diagram showing the Y-axis direction scanning of laser light in the first embodiment; FIG. 5 is a diagram showing the X-axis direction scanning of laser light in the first embodiment;

[0009] A galvanometer scanner and a laser processing machine according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the embodiment.

[0010] Embodiment 1. FIG. 1 is a diagram illustrating the configuration of a laser processing machine 1 according to Embodiment 1 of the present disclosure. In FIG. 1, the X-axis, Y-axis, and Z-axis are three axes that are perpendicular to each other. The X-axis and Y-axis are horizontal axes. The Z-axis is a vertical axis. Note that FIG. 1 illustrates an example in which the X-axis and Y-axis are horizontal axes and the Z-axis is a vertical axis. However, the X-axis, Y-axis, and Z-axis may be three axes that are perpendicular to each other. The X-axis and Y-axis do not necessarily have to be horizontal axes, and the Z-axis does not necessarily have to be a vertical axis. For example, the Y-axis and Z-axis may be horizontal axes, and the X-axis may be a vertical axis. The α-axis and β-axis are axes that are parallel to a plane 23 on which a galvanometer mirror 21 is mounted, and are two axes that are perpendicular to each other. FIG. 1 illustrates a case in which the α-axis is parallel to the X-axis direction and the β-axis is parallel to the YZ plane.

[0011] The laser processing machine 1 processes a workpiece 90 by irradiating it with laser light. The laser processing machine 1 is, for example, a micro laser processing machine. The workpiece 90 is, for example, a printed wiring board mounted on an electronic device or the like. The laser processing machine 1 includes an oscillator 10, a galvanometer scanner 20, a focusing lens 30, an XY table 40, and a control device 50.

[0012] The oscillator 10 outputs a laser beam 60 a toward the galvano scanner 20 .

[0013] The galvanometer scanner 20 includes a galvanometer mirror 21 and a driver 22. The galvanometer mirror 21 has a dome-shaped curved mirror surface, and the laser light 60a output from the oscillator 10 is reflected by the dome-shaped curved mirror surface. The dome-shaped curved mirror surface can be locally regarded as a planar mirror surface with a specific surface orientation depending on each position. Therefore, because the beam diameter of the laser light is very small, the reflective surface of the dome-shaped curved mirror surface onto which the laser light 60a output from the oscillator 10 is incident can also be regarded as a planar mirror surface with a specific surface orientation. The term "reflective surface" as used herein refers to a mirror surface on the galvanometer mirror 21 that is within the same range as the beam diameter of the incident laser light 60a.

[0014] The driver 22 has a plane 23 on which the galvanometer mirror 21 is mounted, and translates the galvanometer mirror 21 in a direction parallel to the plane 23 through control in accordance with a position command. As shown in FIG. 1 , the galvanometer scanner 20 is preferably arranged so that the plane 23 on which the galvanometer mirror 21 is mounted is not parallel to, but is moderately tilted with respect to, the output direction of the laser beam 60a output from the oscillator 10. For example, when the laser processing machine 1 is configured as shown in FIG. 1 , the tilt of the plane 23 with respect to the output direction of the laser beam 60a output from the oscillator 10 can be defined by the direction of the β-axis. In this case, an example of a moderate tilt is when the plane 23 is arranged so that the β-axis is tilted 135 degrees counterclockwise with respect to the output direction of the laser beam 60a (i.e., the +Y-axis direction).

[0015] The reason why such an arrangement is desirable will be explained. For example, if the galvanometer scanner 20 is arranged so that the β-axis direction of the plane 23 on which the galvanometer mirror 21 is placed is parallel to the output direction of the laser light 60a, even if the galvanometer mirror 21 is translated in the β-axis direction, the position of the reflecting surface onto which the laser light 60a output from the oscillator 10 is incident does not change, and therefore the orientation of the reflecting surface cannot be changed. Therefore, in order to scan the workpiece 90 with the laser light in the Y-axis direction without changing the orientation of the reflecting surface, it is necessary to translate the galvanometer mirror 21 in the β-axis direction by the same distance as the distance by which the irradiation position of the laser light on the workpiece 90 is to be moved in the Y-axis direction.

[0016] 1 , if the galvanometer scanner 20 is arranged so that the plane 23 on which the galvanometer mirror 21 is placed is appropriately inclined with respect to the output direction of the laser beam 60a output from the oscillator 10, laser beam scanning can be performed by controlling the change in the orientation of the reflecting surface, so that the distance by which the galvanometer mirror 21 is translated in the β-axis direction is shorter than the distance by which the laser beam irradiation position on the workpiece 90 is to be moved in the Y-axis direction. Therefore, when the galvanometer mirror 21 is translated at the same speed and the same distance is to be scanned with laser beam on the workpiece 90, the distance by which the galvanometer mirror 21 is translated can be shorter when the galvanometer scanner 20 is arranged so that the plane 23 is inclined with respect to the output direction of the laser beam than when the galvanometer scanner 20 is arranged so that the plane 23 is parallel to the output direction of the laser beam. This shortens the time required for laser beam scanning and enables faster driving.

[0017] Furthermore, when the galvanometer scanner 20 is arranged so that the plane 23 is parallel to the output direction of the laser beam, it is necessary to ensure a movable range equivalent to the width of the processing area on the workpiece 90 to be scanned with the laser beam as a movable range in which the galvanometer mirror 21 can be translated without interfering with the surroundings, whereas when the galvanometer scanner 20 is arranged so that the plane 23 is tilted with respect to the output direction of the laser beam, it is sufficient to ensure a movable range narrower than the processing area on the workpiece 90 to be scanned with the laser beam. Therefore, it is possible to design the mechanism of the laser processing machine without any restrictions when the galvanometer scanner 20 is arranged so that the plane 23 is tilted with respect to the output direction of the laser beam, rather than when the galvanometer scanner 20 is arranged so that the plane 23 is parallel to the output direction of the laser beam.

[0018] Fig. 2 is a perspective view of the galvanometer scanner 20. As shown in Fig. 2, the driver 22 has an α-axis direction driver 22α that moves the galvanometer mirror 21 in an α-axis direction parallel to a plane 23 on which the galvanometer mirror 21 is placed, and a β-axis direction driver 22β that moves the galvanometer mirror 21 in a β-axis direction that is parallel to the plane 23 on which the galvanometer mirror 21 is placed and perpendicular to the α-axis direction.

[0019] 2, the galvanometer mirror 21 is placed on the plane 23 on the α-axis direction driver 22α, but the order of the α-axis direction driver 22α and the β-axis direction driver 22β may be reversed, and the galvanometer mirror 21 may be placed on the plane on the β-axis direction driver 22β. Furthermore, instead of placing the galvanometer mirror 21 directly on the α-axis direction driver 22α or the plane on the β-axis direction driver 22β, the galvanometer mirror 21 may be placed on a top table having a plane including the α-axis direction and the β-axis direction, and the galvanometer mirror 21 may be translated by driving the top table with the α-axis direction driver 22α and the β-axis direction driver 22β.

[0020] By interlocking the α-axis driver 22α and the β-axis driver 22β, the galvanometer mirror 21 can be translated to any position in two-dimensional directions including the α-axis and β-axis directions. Note that the α-axis and β-axis need not necessarily be orthogonal to each other, as long as they are in a coordinate system that can identify the two-dimensional position to which the galvanometer mirror 21 is translated. In other words, the α-axis and β-axis need only be parallel to the plane 23 on which the galvanometer mirror 21 is placed and different from each other.

[0021] The drive unit 22 can be configured, for example, by a motor-driven two-axis linear actuator. When the laser beam 60c is scanned only one-dimensionally on the processing surface of the workpiece 90, the drive unit 22 does not necessarily have to include a two-axis drive unit, and may be configured with only a one-axis drive unit. Note that, hereinafter, the α-axis drive unit 22α and the β-axis drive unit 22β will be referred to as the drive unit 22 unless they are to be individually distinguished.

[0022] 1 , the condenser lens 30 is an fθ lens that condenses the laser beam 60b reflected by the dome-shaped curved mirror surface of the galvanometer mirror 21 and irradiates the laser beam 60c perpendicularly onto the workpiece 90 placed on the XY table 40. The position at which the laser beam 60b is irradiated onto the workpiece 90 is determined depending on the position at which the laser beam 60b is incident on the condenser lens 30. In other words, there is a one-to-one correspondence between the position at which the laser beam 60b is incident onto the condenser lens 30 and the position at which the laser beam 60c is irradiated onto the workpiece 90.

[0023] The XY table 40 has a mounting surface 41 on which the workpiece 90 is placed, and moves the workpiece 90 in two-dimensional directions, including the X-axis and Y-axis directions, under control in accordance with a position command. If the processing area for the workpiece 90 is small and the laser light 60c can be scanned over the processing area by driving the galvanometer scanner 20 alone, it is not necessary to use the XY table 40 to move the workpiece 90; the workpiece 90 may be placed on a fixed base (not shown) with a fixed mounting surface instead of the XY table 40. The XY table 40 and the fixed base both have a planar mounting surface on which the workpiece 90 is placed, but differ in whether the mounting surface is movable. In other words, the XY table 40 and the fixed base are mounting bases on which the workpiece 90 is placed.

[0024] In terms of laser beam scanning positioning accuracy, it is desirable that the galvanometer scanner 20 be disposed so that the plane 23 on which the galvanometer mirror 21 is mounted is not parallel to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is mounted (the Z-axis direction in FIG. 1 ), but is moderately tilted. For example, when the laser processing machine 1 is configured as shown in FIG. 1 , the tilt of the plane 23 with respect to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is mounted can be defined by the direction of the β-axis. In this case, an example of a moderate tilt is when the plane 23 is disposed so that the β-axis is tilted 45 degrees counterclockwise with respect to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is mounted (i.e., the +Z-axis direction).

[0025] The reason why such an arrangement is desirable will be explained. For example, in FIG. 1 , when the galvanometer scanner 20 is arranged so that the β-axis direction of the plane 23 on which the galvanometer mirror 21 is placed is parallel to the Z-axis direction, the rate of change in the orientation of the reflecting surface relative to the translational movement distance of the galvanometer mirror in the β-axis direction is larger than when the plane 23 is arranged so that the β-axis direction is inclined with respect to the Z-axis direction. Therefore, even a small translational movement of the galvanometer mirror in the β-axis direction (i.e., the Z-axis direction) results in a large change in the orientation of the reflecting surface, and accordingly, a large change in the scanning position of the laser light. Therefore, the scanning positioning accuracy of the laser light is easily affected by positioning errors of the galvanometer mirror.

[0026] On the other hand, when the galvanometer scanner 20 is arranged so that the β-axis direction of the plane 23 on which the galvanometer mirror 21 is placed is inclined at an appropriate angle with respect to the Z-axis direction, the rate of change in the orientation of the reflecting surface with respect to the translational movement distance of the galvanometer mirror in the β-axis direction is smaller than when the β-axis direction of the plane 23 is placed parallel to the Z-axis direction. Therefore, the laser beam scanning positioning accuracy is less susceptible to the influence of positioning errors of the galvanometer mirror 20. Therefore, it is easier to achieve high-precision laser beam scanning when the galvanometer scanner 20 is arranged so that the plane 23 on which the galvanometer mirror 21 is placed is inclined at an appropriate angle with respect to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is placed.

[0027] The control device 50 controls the entire laser processing machine 1. That is, the control device 50 controls the operation of the oscillator 10, the galvanometer scanner 20, and the XY table 40. Specifically, the control device 50 moves the workpiece 90 using the XY table 40 so that the processing area on the workpiece 90 is within the scannable range of the laser beam 60c, and then controls the galvanometer scanner 20 in accordance with a target scanning position setting, which is a target position on the workpiece 90 to be irradiated with the laser beam 60c, so that the laser beam 60c is incident on the target scanning position. That is, the control device 50 controls the galvanometer scanner 20 so that the laser beam 60b is incident on the target irradiation position, which is an irradiation position on the condenser lens 30 corresponding to the target scanning position. FIG. 3 is a diagram showing the configuration of the control device 50. The control device 50 includes a command generation unit 51 that generates various commands, a laser control unit 55, a galvanometer control unit 56, and an XY table control unit 57.

[0028] The command generating unit 51 has an XY table position command generating unit 52 that generates a position command for the XY table 40, a galvanometer position command generating unit 53 that generates a position command for the galvanometer scanner 20, and a laser output command generating unit 54 that generates a laser output command. The laser control unit 55 controls the oscillator 10 in accordance with the laser output command generated by the laser output command generating unit 54. The galvanometer control unit 56 controls the galvanometer scanner 20 in accordance with the position command generated by the galvanometer position command generating unit 53. The galvanometer control unit 56 controls the translational movement of the galvanometer mirror 21 by the driving unit 22, thereby positioning the galvanometer mirror 21. The XY table control unit 57 controls the movement of the XY table 40 in accordance with the position command generated by the XY table position command generating unit 52, thereby positioning the workpiece 90 placed on the XY table 40.

[0029] Next, the operation of the laser processing machine 1 will be described.

[0030] Because the galvanometer mirror 21 has a dome-shaped curved mirror surface, the orientation of the reflecting surface (the direction in which the reflecting surface faces) with respect to the incident direction can be changed by translating the galvanometer mirror 21 to control the position of the reflecting surface onto which the laser light 60a output from the oscillator 10 is incident, thereby making it possible to reflect the laser light 60a in any direction. As an example, the operation of moving the irradiation position on the workpiece 90 in the Y-axis direction will be described.

[0031] Fig. 4 is a diagram for explaining scanning of the laser light in the Y-axis direction. Fig. 4 shows a schematic diagram of how the reflection direction of the laser light changes and the irradiation position on the workpiece 90 moves in the Y-axis direction depending on the position to which the galvanometer mirror 21 is translated in the β-axis direction in the laser processing machine 1 shown in Fig. 1. Note that the XY table 40 is not driven, and the position of the workpiece 90 is fixed.

[0032] 4A shows the irradiation position of the laser light when laser light 61a output from the oscillator 10 in the horizontal direction (+Y-axis direction) is reflected in the vertical direction (−Z-axis direction) by reflecting surface M1 on the galvanometer mirror 21. FIG. 4B shows the reflection direction and irradiation position of the laser light when laser light 62a output from the oscillator 10 in the horizontal direction (+Y-axis direction) is reflected by reflecting surface M2 on the galvanometer mirror 21 after the galvanometer mirror 21 is translated in the +β-axis direction from the state shown in FIG. 4A. FIG. 4C shows the reflection direction and irradiation position of the laser light when laser light 63a output from the oscillator 10 in the horizontal direction (+Y-axis direction) is reflected by reflecting surface M3 on the galvanometer mirror 21 after the galvanometer mirror 21 is translated in the −β-axis direction from the state shown in FIG. 4A.

[0033] 4(b), the position of the reflective surface on the galvanometer mirror 21 onto which the laser light is incident also moves relatively from reflective surface M1 to reflective surface M2, with the reflective surface orientation being tilted more in the +Y-axis direction than reflective surface M1. Therefore, the direction of the reflected light is tilted more in the +Y-axis direction for laser light 62b than for laser light 61b, so the position of irradiation on the focusing lens 30 moves in the +Y-axis direction from L1 to L2. As a result, the irradiation position of laser light 62c irradiated onto the workpiece 90 also moves in the +Y-axis direction from W1 to W2.

[0034] When the galvanometer mirror 21 is translated in the -β-axis direction, the opposite operation to the above occurs. That is, when the galvanometer mirror 21 is translated in the -β-axis direction from the position shown in FIG. 4A to the position shown in FIG. 4C, the position of the reflective surface on the galvanometer mirror 21 onto which the laser light is incident also moves relatively from reflective surface M1 to reflective surface M3, and the orientation of the reflective surface is tilted more in the -Y-axis direction for reflective surface M3 than for reflective surface M1. Therefore, the direction of the reflected light is tilted more in the -Y-axis direction for laser light 63b than for laser light 61b, so the position of irradiation on the focusing lens 30 moves in the -Y-axis direction from L1 to L3. As a result, the irradiation position of laser light 63c irradiated on the workpiece 90 also moves in the -Y-axis direction from W1 to W3.

[0035] As a similar example, an operation will be described in which the irradiation position on the workpiece 90 is moved in the X-axis direction. Fig. 5 is a diagram for explaining the scanning of the laser light in the X-axis direction. Fig. 5 schematically shows how the reflection direction of the laser light changes and the irradiation position on the workpiece 90 moves in the X-axis direction depending on the position to which the galvanometer mirror 21 is translated in the α-axis direction in the laser processing machine 1 shown in Fig. 1. Note that the XY table 40 is not driven, and the position of the workpiece 90 is fixed.

[0036] Fig. 5A shows the same state as Fig. 4A. Fig. 5B shows the reflection direction and irradiation position of laser light when laser light 64a output from the oscillator 10 in the horizontal direction (+Y-axis direction) is reflected by reflecting surface M4 on the galvanometer mirror 21 after translational movement of the galvanometer mirror 21 in the +α-axis direction (i.e., the +X-axis direction) from the state of Fig. 5A. Fig. 5C shows the reflection direction and irradiation position of laser light when laser light 65a output from the oscillator 10 in the horizontal direction (+Y-axis direction) is reflected by reflecting surface M5 on the galvanometer mirror 21 after translational movement of the galvanometer mirror 21 in the −α-axis direction (i.e., the −X-axis direction) from the state of Fig. 5A.

[0037] 5A to the position shown in FIG. 5B, the position of the reflective surface on the galvanometer mirror 21 onto which the laser light is incident also moves relatively from reflective surface M1 to reflective surface M4, and the orientation of the reflective surface is tilted more in the −X-axis direction for reflective surface M4 than for reflective surface M1. Therefore, the direction of the reflected light is tilted more in the −X-axis direction for laser light 64b than for laser light 61b, so the position of irradiation on the focusing lens 30 moves in the −X-axis direction from L1 to L4. As a result, the irradiation position of laser light 64c irradiated onto the workpiece 90 also moves in the −X-axis direction from W1 to W4.

[0038] When the galvanometer mirror 21 is translated in the −α-axis direction, the opposite operation to the above occurs. That is, when the galvanometer mirror 21 is translated in the −α-axis direction from the position shown in FIG. 5A to the position shown in FIG. 5C, the position of the reflective surface on the galvanometer mirror 21 onto which the laser light is incident also moves relatively from reflective surface M1 to reflective surface M5, and the orientation of the reflective surface is tilted more toward the +X-axis direction for reflective surface M5 than for reflective surface M1. Therefore, the direction of the reflected light is tilted more toward the +X-axis direction for laser light 65b than for laser light 61b, so the position of irradiation on the focusing lens 30 moves from L1 to L5 in the +X-axis direction. As a result, the irradiation position of laser light 65c irradiated on the workpiece 90 also moves from W1 to W5 in the +X-axis direction.

[0039] Furthermore, by interlocking the α-axis direction driver 22α and the β-axis direction driver 22β to translate the galvanometer mirror 21 to any position in two-dimensional directions including the α-axis direction and the β-axis direction, and by making the laser light output from the oscillator 10 incident on a reflective surface having a specific surface orientation among the dome-shaped curved mirror surfaces, the laser light can be reflected in any direction, and as a result, the laser light can be irradiated at any position on the condenser lens 30. As a result, the laser light can be irradiated at any position on the workpiece 90.

[0040] In this way, the control device 50 controls the position at which the galvanometer mirror 21 is translated, and by reflecting the laser light output from the oscillator 10 on a reflective surface having a surface oriented in a specific direction, it is possible to adjust the position at which the laser light is incident on the condenser lens 30. Since the laser light is irradiated perpendicularly from the condenser lens 30 onto the workpiece 90, if the position at which the laser light is incident on the condenser lens 30 can be adjusted, the position at which the laser light is incident on the workpiece 90 can be adjusted.

[0041] Next, a method for controlling the position of the translational movement of the galvanometer mirror will be described. As an example, a case where laser light is scanned in the Y-axis direction as shown in FIG. 4 will be described using FIG. 6. FIG. 6(a) is a schematic diagram of the state of FIG. 4(a) as viewed from the +X-axis direction. FIG. 6(b) is a schematic diagram of the state of FIG. 4(b) as viewed from the +X-axis direction. To simplify the description, as an example, the galvanometer mirror 21a shown in FIG. 6 has a hemispherical mirror surface. Note that only the vicinity of the laser light incident on the galvanometer mirror 21a is shown in FIG. 6. Furthermore, when the galvanometer mirror 21a has a hemispherical mirror surface, the position of the galvanometer mirror 21a can be represented, for example, by the position of the center point of the hemispherical mirror surface of the galvanometer mirror 21a. In the state shown in FIG. 6(a), the position of the center point of the hemispherical mirror surface of the galvanometer mirror 21a is at P1, and in the state shown in FIG. 6(b), the position of the center point of the hemispherical mirror surface of the galvanometer mirror 21a is at P2.

[0042] FIG. 6A shows a state in which laser light 61a output from oscillator 10 in the horizontal direction (+Y-axis direction) is reflected in the vertical direction (-Z-axis direction) by reflecting surface M1. In the case of FIG. 6A, according to the law of light reflection, the angle of incidence θ1 and the angle of reflection θ1' are equal, so the angle of incidence θ1 = angle of reflection θ1' = 45 degrees. The orientation of the reflecting surface is equal to the direction of the normal to the reflecting surface, so it can be expressed by the direction of the normal to the reflecting surface. In the case of FIG. 6A, if the orientation of reflecting surface M1, i.e., the direction of the normal h1 to reflecting surface M1, is represented by the illustrated direction θh1, θh1 is equal to the angle of incidence θ1, which is 45 degrees. Therefore, the orientation of reflecting surface M1 is θh1 = 45 degrees.

[0043] In other words, by making the laser light 61a output from the oscillator 10 in the horizontal direction (+Y-axis direction) incident on the reflecting surface M1 having a normal h1 whose normal direction is θh1 = 45 degrees, the incident angle θ1 = normal direction θh1 = 45 degrees and the reflection angle θ1' = incident angle θ1 = 45 degrees, so that the laser light 61b can be reflected in the vertical direction (-Z-axis direction).

[0044] 6(b) shows that when galvanometer mirror 21a is translated in the +β-axis direction from the position shown in FIG. 6(a), the center point of the hemispherical mirror surface of galvanometer mirror 21a moves from P1 to P2, and the position of the reflecting surface onto which laser beam 62a output from oscillator 10 in the horizontal direction (+Y-axis direction) is incident moves from reflecting surface M1, which has a normal h1 in the direction of θh1, to reflecting surface M2, which has a normal h2 in the direction of θh2. As a result, the reflection direction of the laser beam changes from laser beam 61b to laser beam 62b. As a result, the position of the laser beam irradiated on focusing lens 30 moves from L1 to L2 in the +Y-axis direction, and the irradiation position on workpiece 90 also moves from W1 to W2 in the +Y-axis direction. In this case, the relationship of incident angle θ2 = normal direction θh2 and reflection angle θ2' = incident angle θ2 is satisfied.

[0045] In other words, by translating the galvanometer mirror 21a so that the position of the center point of the hemispherical mirror surface of the galvanometer mirror 21a is P2, and by making the laser light 62a output from the oscillator 10 in the horizontal direction (+Y-axis direction) incident on the reflecting surface M2 having a normal h2 in the direction of θh2, the incident light laser light 62a can be reflected in the direction of the laser light 62b, which is reflected light that satisfies the relationship of incident angle θ2 = normal direction θh2 and reflection angle θ2' = incident angle θ2.As a result, the laser light 62b can be irradiated to position L2, which is the target irradiation position on the focusing lens 30, and the laser light 62c can be irradiated to position W2, which is the target scanning position on the workpiece 90.

[0046] Therefore, in order to set the position W2 on the workpiece 90 as the target scanning position and irradiate this target scanning position W2 with laser light, the galvanometer mirror 21a is translated so that the position of the center point of the hemispherical mirror surface of the galvanometer mirror 21a becomes P2. Note that, although Fig. 6 has described an example in which the galvanometer mirror 21a has a hemispherical mirror surface, the same explanation applies to a case in which the galvanometer mirror 21a has a mirror surface shaped like a cut-out portion of a sphere.

[0047] In this way, by calculating the position on the galvanometer mirror of the reflecting surface having a surface orientation that allows reflection toward the target irradiation position on the condenser lens 30, which corresponds to the target scanning position on the workpiece 90, and calculating the position of the galvanometer mirror that allows the laser light output from the oscillator to be incident on the reflecting surface, the position of the galvanometer mirror can be controlled and the laser light can be irradiated onto the target irradiation position on the condenser lens 30. As a result, the laser light can be scanned toward the target scanning position on the workpiece 90.

[0048] FIG. 7 is a diagram showing the configuration of the galvanometer position command generator 53. The galvanometer position command generator 53 includes a reflecting surface position calculator 58 and a galvanometer mirror position calculator 59. The reflecting surface position calculator 58 acquires a target scanning position set from an input unit (not shown), calculates a target irradiation position on the condenser lens 30 corresponding to the target scanning position, and calculates the position on the galvanometer mirror 21a of the reflecting surface having a surface orientation that allows the laser light output from the oscillator 10 to be reflected toward the target irradiation position. Based on the reflecting surface position on the galvanometer mirror 21a calculated by the reflecting surface position calculator 58, the galvanometer mirror position calculator 59 calculates the position of the galvanometer mirror 21a at which the laser light output from the oscillator 10 can be incident on the reflecting surface, and generates a corresponding position command based on the calculated position. With this configuration, the galvanometer position command generator 53 generates a position command for the galvanometer scanner 20.

[0049] As an example, a case where the current galvanometer mirror 21a is at the position of the center point P1 of the galvanometer mirror 21a shown in (a) of FIG. 6 and the position of the center point P2 of the galvanometer mirror 21a shown in (b) of FIG. 6, which is the target position of the next galvanometer mirror 21a, will be described with reference to FIG. 8.

[0050] The position of the galvanometer mirror 21a relative to the incident light in Fig. 8 shows the same state as Fig. 6(a). That is, the current position of the center point of the galvanometer mirror 21a is at P1, and when laser light 61a is output from the oscillator 10 in the horizontal direction (+Y-axis direction) in this state, it is incident on the reflecting surface M1, and the laser light 61b reflected by the reflecting surface M1 is irradiated at the position L1 on the condenser lens 30.

[0051] In such a case, the reflecting surface position calculation unit 58 first calculates coordinate position information of the next target irradiation position L2 on the condenser lens 30 based on the set next target scanning position W2. From the coordinate position information of the reflecting surface M1 and the coordinate position information of the target irradiation position L2, the reflection direction of the laser beam 62b, which is the next target reflected light, as shown in Fig. 8 is calculated. In other words, the target reflection direction, which is the direction in which the laser beam is reflected toward the next target irradiation position L2 on the condenser lens 30, is calculated.

[0052] Next, the reflecting surface position calculation unit 58 determines the orientation of the surface required to reflect the laser beam 61a in the direction of the laser beam 62b (i.e., the target reflection direction) when the laser beam 61a is incident on the galvanometer mirror 21a, based on the incident direction of the laser beam 61a and the reflected direction of the laser beam 62b. This is equivalent to determining the midpoint direction of the angle formed by the laser beam 61a and the laser beam 62b, based on the law of light reflection. In FIG. 8, the direction of the line h2' is shown to be the midpoint direction of the angle formed by the laser beam 61a and the laser beam 62b. In other words, the direction of the line h2' is the orientation of the surface required to reflect the laser beam 61a in the direction of the laser beam 62b when the laser beam 61a is incident on the galvanometer mirror 21a.

[0053] Next, the reflecting surface position calculation unit 58 determines the position of the reflecting surface M2 on the surface of the galvanometer mirror 21a, which has the surface orientation required to reflect the laser light 62b in the direction of the laser light 62b. This can be determined by translating the line h2' so that it passes through the center point P1 of the galvanometer mirror 21a, defining the line as a normal line h2", and determining the point where this normal line h2" intersects with the surface of the galvanometer mirror 21a as the position of the reflecting surface M2, as shown in Fig. 8.

[0054] Next, the galvanometer mirror position calculation unit 59 calculates the position of center point P2, which is the target position to which the galvanometer mirror 21a is to be translated. This can be calculated as follows. As shown in Fig. 8, P3 is the position where a line extending from the center point of the reflecting surface M2 in the +β-axis direction intersects with the extension of the laser light 61a. If V1 is a vector having the center point of the reflecting surface M2 as its start point and P3 as its end point, the position of the end point of vector V2 obtained by moving the start point of vector V1 to the center point P1 of the galvanometer mirror 21a is the position of center point P2, which is the target position to which the galvanometer mirror 21a is to be translated.

[0055] By translating the galvanometer mirror 21a so that the position of the center point of the galvanometer mirror 21a coincides with the position of the center point P2 of the galvanometer mirror 21a determined as described above, the reflecting surface M2 shown in FIG. 8 moves to a position P3, and the laser beam 61a becomes incident on the reflected surface M2 after the movement. Because the reflecting surface M2 is oriented so as to reflect the laser beam 62b in the direction of the laser beam 62b, the laser beam 61a incident on the reflecting surface M2 is reflected in the direction of the laser beam 62b, and the laser beam 62b is irradiated onto the target irradiation position L2 on the condenser lens 30. As a result, the laser beam 62c can be scanned at the position W2 on the workpiece 90.

[0056] By controlling the position of the galvanometer mirror 21a in the β-axis direction in this manner, it is possible to irradiate the laser beam at any position in the Y-axis direction on the condenser lens 30, and as a result, it is possible to scan the laser beam at any position in the Y-axis direction on the workpiece 90. Similarly, when scanning the laser beam in the X-axis direction, by controlling the position of the galvanometer mirror 21a in the α-axis direction, it is possible to irradiate the laser beam at any position in the X-axis direction on the condenser lens 30, and as a result, it is possible to scan the laser beam at any position in the X-axis direction on the workpiece 90. Furthermore, by combining these types of control and controlling the positions of the galvanometer mirror 21a in the α-axis and β-axis directions, it is possible to irradiate the laser beam at any position on the condenser lens 30, and as a result, it is possible to scan the laser beam at any position on the workpiece 90.

[0057] 8 has been described as an example in which the position of the reflecting surface M2 and the target position to which the galvanometer mirror 21a is to be translated are geometrically calculated for a case in which the galvanometer mirror 21a has a hemispherical mirror surface, but this method is not limited to this. For example, in cases in which the galvanometer mirror 21a has not only a hemispherical mirror surface but also a mirror surface shaped like a partially cut-away sphere or a dome-shaped curved mirror surface, the three-dimensional shape of the galvanometer mirror being used and the positional relationship between the galvanometer mirror and the oscillator may be modeled and registered in advance in a storage unit (not shown), and this model may be used so that the reflecting surface position calculation unit 58 can calculate the position of the reflecting surface M2 on the galvanometer mirror 21a and the galvanometer mirror position calculation unit 59 can calculate the target position to which the galvanometer mirror 21a is to be translated.

[0058] Next, the flow of the laser beam scanning positioning process will be described. Figure 9 is a flowchart illustrating the laser beam scanning positioning process. First, the reflecting surface position calculation unit 58 acquires the target scanning position of the laser beam with respect to the workpiece 90 (step 1). Specifically, the reflecting surface position calculation unit 58 acquires the target scanning position set from an input unit (not shown). Note that a plurality of target scanning positions required for performing laser processing of the workpiece 90 into the target processing shape may be stored in advance in a storage unit (not shown), and the reflecting surface position calculation unit 58 may acquire the required target scanning position each time from the storage unit.

[0059] Next, the reflecting surface position calculation unit 58 calculates the next target irradiation position on the condenser lens 30 from the acquired target scanning position, and calculates the position of the reflecting surface on the galvanometer mirror 21 onto which the laser light is next incident (step 2). Specifically, the position of the reflecting surface having a surface orientation that allows reflection to the next target irradiation position on the condenser lens 30 is calculated using the method described in Fig. 8 or the like.

[0060] Next, the galvanometer mirror position calculation unit 59 calculates the target position of the galvanometer mirror 21 to be translated next (step 3). Specifically, the galvanometer mirror position calculation unit 59 calculates the position of the galvanometer mirror 21 at which the laser light can be incident on the position of the reflecting surface calculated in step 2, using the method described in Fig. 8 or the like. That is, by controlling the positions of the galvanometer mirror 21 in the α-axis and β-axis directions, the position of the galvanometer mirror 21 is calculated so that the position of the reflecting surface calculated in step 2 is on the trajectory of the laser light output from the oscillator 10.

[0061] Next, the galvanometer mirror position calculation unit 59 generates and outputs a position command for the galvanometer scanner 20 based on the target position of the galvanometer mirror 21 calculated in step 3 (step 4). Next, the galvanometer control unit 56 controls the galvanometer scanner 20 in accordance with the position command for the galvanometer scanner 20 to translate the galvanometer mirror 21 to the target position of the galvanometer mirror 21 (step 5). Then, the laser light output from the oscillator 10 is reflected by the reflecting surface located at the position calculated in step 2, passes through the target irradiation position on the condenser lens 30, and is irradiated onto the target scanning position on the workpiece 90 (step 6).

[0062] Specifically, as a result of step 5, the position of the reflecting surface onto which the laser light output from the oscillator 10 is incident moves to the position of the reflecting surface calculated in step 2 in accordance with the translational movement of the galvanometer mirror 21, and the change in the orientation of the reflecting surface adjusts the reflection direction of the laser light, and the irradiation position of the laser light on the condenser lens 30 moves to the target irradiation position. When the laser light is irradiated onto the target irradiation position on the condenser lens 30, the laser light is condensed by the condenser lens 30, and the laser light is irradiated onto the target scanning position on the workpiece 90.

[0063] By repeating the processes from step 1 to step 6 while changing the target scanning position of the laser light on the workpiece 90, the desired laser processing can be performed on the workpiece 90.

[0064] As described above, the galvanometer scanner in this embodiment reflects laser light in any direction by translating a galvanometer mirror having a dome-shaped curved mirror surface. Therefore, unlike conventional galvanometer scanners, a planar galvanometer mirror is not rotated, and therefore, tilt vibration and torsional vibration do not occur, making it possible to achieve both faster driving and improved scanning positioning accuracy.

[0065] Furthermore, in laser processing machines that use conventional galvanometer scanners, multiple planar galvanometer mirrors are required to scan laser light at any position, and the effects of manufacturing errors and thermal deformation, etc., resulting from each galvanometer mirror are added together, affecting the scanning positioning accuracy and resulting in a problem of deteriorating processing accuracy. In contrast, the laser processing machine in this embodiment requires only one galvanometer mirror, and can be realized with fewer galvanometer mirrors than conventional machines, so the effects on processing accuracy due to manufacturing errors and thermal deformation, etc., of the galvanometer mirrors can also be suppressed.

[0066] Embodiment 2. When laser light is reflected by a flat mirror surface, as in conventional galvanometer scanners, the reflected laser light propagates into the space on the optical path without spreading, just like the incident light, whereas when laser light is reflected by a dome-shaped curved mirror surface as in embodiment 1, the reflected laser light propagates into the space on the optical path with a spread angle according to the curvature of the reflecting surface. Therefore, the beam diameter of the laser light when it reaches the collecting lens becomes larger than the beam diameter of the laser light output from the oscillator, in proportion to the size of this spread angle and the distance between the galvanometer mirror and the collecting lens.

[0067] Furthermore, if the galvanometer mirror has a hemispherical mirror surface, the curvature is the same regardless of the direction on the mirror surface, so the beam shape of the reflected laser light will be the same as that of the incident light, but if the galvanometer mirror has a curved mirror surface with a curvature that varies depending on the direction on the mirror surface, the beam shape of the reflected laser light will be deformed to a shape different from the beam shape of the laser light before reflection. Therefore, even if a laser light with a circular beam shape is output from the oscillator, if it is reflected by a galvanometer mirror with a curved mirror surface with a curvature that varies depending on the direction on the mirror surface, the beam shape of the reflected laser light will be deformed to an ellipse.

[0068] As described above, the beam diameter and beam shape of the laser light change before and after reflection by the galvanometer mirror, which may reduce the focusability of the laser light passing through the condenser lens 30 and reduce processing accuracy. Therefore, in the second embodiment, a laser processing machine will be described that can correct the beam diameter and beam shape of the laser light after reflection to suppress the reduction in focusability of the laser light passing through the condenser lens 30. Descriptions of the same parts as in the first embodiment will be omitted, and only parts that differ from the first embodiment will be described.

[0069] Fig. 10 is a diagram showing the configuration of a laser processing machine 1A according to the second embodiment. The configurations of the galvanometer scanner and the control device according to the second embodiment are the same as those of the galvanometer scanner and the control device according to the first embodiment, and therefore a description thereof will be omitted. Fig. 10 differs from the first embodiment in that an optical component 70 is provided between the mirror surface of the galvanometer mirror 21 and the optical path of the condenser lens 30. The optical component 70 corrects the laser light 60d reflected by the mirror surface of the galvanometer mirror 21, and irradiates the condenser lens 30 with the corrected laser light 60e.

[0070] 11 is a diagram illustrating, as an example, correction of the beam diameter of laser light by the optical component 70 when a galvanometer mirror 21a having a hemispherical mirror surface is used. As shown in Fig. 11, laser light 60d reflected by the galvanometer mirror 21a having a hemispherical mirror surface propagates while expanding toward the optical component 70. Therefore, the beam diameter of the laser light 60d when it reaches the optical component 70 becomes larger than the beam diameter of the laser light 60a output from the oscillator 10.

[0071] The optical component 70 corrects the laser beam 60d reflected by the galvanometer mirror 21a so that the beam diameter of the laser beam 60e passing through the optical component 70 and entering the condenser lens 30 is the same as the beam diameter of the laser beam 60a output from the oscillator 10. As a result, the laser beam 60e entering the condenser lens 30 has the same beam diameter as the laser beam 60a output from the oscillator 10, and this makes it possible to suppress a decrease in the focusing ability of the laser beam 60e passing through the condenser lens 30. As a result, it is possible to reduce processing defects due to a decrease in the focusing ability of the laser beam. Note that if such an optical component 70 is not used, the focusing ability of the laser beam may be corrected by previously adjusting the refractive index of the condenser lens 30 in consideration of the expansion rate of the beam diameter of the laser beam 60d reflected by the galvanometer mirror 21a.

[0072] 11 has been described as an example in which the galvanometer mirror 21a having a hemispherical mirror surface is used, but if the galvanometer mirror 21 has a curved mirror surface whose curvature varies depending on the direction on the mirror surface, not only the beam diameter but also the beam shape of the laser light will change before and after reflection by the galvanometer mirror 21. For this reason, even if a laser light having a circular beam shape is output from the oscillator 10, if it is reflected by the galvanometer mirror 21 having a curved mirror surface whose curvature varies depending on the direction on the mirror surface, the beam shape of the reflected laser light will be deformed into an ellipse.

[0073] In such a case, the optical component 70 may correct not only the beam diameter of the laser beam but also the beam shape of the laser beam. In this case, in addition to correcting the beam diameter of the laser beam, the optical component 70 corrects the laser beam 60d reflected by the galvanometer mirror 21 so that the beam shape of the laser beam 60e incident on the condenser lens 30 becomes circular. As a result, the laser beam that has been corrected to have an appropriate beam diameter and beam shape is incident on the condenser lens 30, so that the decrease in the focusing ability of the laser beam passing through the condenser lens 30 can be further suppressed.

[0074] As described above, the laser processing machine 1A in this embodiment can suppress a decrease in the focusing ability of the laser light passing through the focusing lens 30 by correcting the beam diameter and beam shape of the laser light using the optical component 70 and allowing the appropriate laser light to be incident on the focusing lens 30, and as a result, can reduce processing defects caused by a decrease in the focusing ability of the laser light.

[0075] Next, a description will be given of the hardware configuration of the control device 50 according to the first and second embodiments. Fig. 12 is a diagram showing an example of the hardware configuration of the control device 50 of the laser processing machine 1, 1A according to the first and second embodiments. Fig. 12 shows the hardware configuration in the case where the functions of the control device 50 are realized by using hardware that executes a program.

[0076] The processor 101 is a CPU (Central Processing Unit). The processor 101 may be a processing device, an arithmetic unit, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor). The memory 102 is a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory).

[0077] The storage device 103 is a hard disk drive (HDD) or a solid state drive (SSD). A program that causes the computer to function as the control device 50 is stored in the storage device 103. The processor 101 reads the program stored in the storage device 103 into the memory 102 and executes it.

[0078] The program may be stored in a storage medium that can be read by a computer system. The control device 50 may store the program recorded on the storage medium in the memory 102. The storage medium may be a portable storage medium such as a flexible disk, or a flash memory such as a semiconductor memory. The program may be installed in the computer system from another computer or a server device via a communication network.

[0079] The functions of the command generating unit 51, the laser control unit 55, the galvanometer control unit 56, and the XY table control unit 57 are realized by a combination of the processor 101 and software. Each of the functions may be realized by a combination of the processor 101 and firmware, or may be realized by a combination of the processor 101, software, and firmware. The software or firmware is written as a program and stored in the storage device 103.

[0080] The interface circuit 104 transmits signals to the oscillator 10, the galvanometer scanner 20, and the XY table 40, which are devices connected to the hardware.

[0081] The configurations shown in the above embodiments are examples of the contents of the present disclosure. The configurations of each embodiment can be combined with other known technologies. The configurations of each embodiment can also be combined as appropriate. Part of the configuration of each embodiment can be omitted or modified without departing from the gist of the present disclosure.

[0082] 1, 1A Laser processing machine, 10 Oscillator, 20 Galvanometer scanner, 21, 21a Galvanometer mirror, 22 Drive unit, 22α α-axis direction drive unit, 22β β-axis direction drive unit, 23 Plane on which the galvanometer mirror is placed, 30 Condenser lens, 40 XY table, 41 Placement surface, 50 Control device, 51 Command generation unit, 52 XY table position command generation unit, 53 Galvanometer position command generation unit, 54 Laser output command generation unit, 55 Laser control unit, 56 Galvanometer control unit, 57 XY table control unit, 58 Reflecting surface position calculation unit, 59 Galvanometer mirror position calculation unit, 60a, 60b, 60c, 60d, 60e, 61a, 61b, 61c, 62a, 62b, 62c, 63a, 63b, 63c, 64a, 64b, 64c, 65a, 65b, 65c laser light, 70 optical components, 90 workpiece, 101 processor, 102 memory, 103 storage device, 104 interface circuit, h1, h2, h2″ normal, h2′ straight line, L1, L2, L3, L4, L5 target irradiation position, M1, M2, M3, M4, M5 reflecting surface, P1, P2 position of the center point of the hemispherical mirror surface of the galvanometer mirror, P3 position of the end point of vector V1, V1, V2 vector, W1, W2, W3, W4, W5 target scanning position.

Claims

1. A galvanometer scanner comprising: a galvanometer mirror having a dome-shaped curved mirror surface; and a drive unit having a flat surface on which the galvanometer mirror is placed, the drive unit translating the galvanometer mirror in a direction parallel to the flat surface.

2. The galvanometer scanner according to claim 1, characterized in that the driving unit comprises: an α-axis direction driving unit that moves the galvanometer mirror in an α-axis direction that is a direction parallel to the plane; and a β-axis direction driving unit that moves the galvanometer mirror in a β-axis direction that is parallel to the plane and different from the α-axis direction.

3. A galvanometer scanner according to claim 1 or 2, characterized in that the galvanometer mirror has a mirror surface shaped like a part of a sphere cut out.

4. A laser processing machine comprising: an oscillator that outputs laser light; a galvanometer scanner according to any one of claims 1 to 3 that reflects the laser light on the mirror surface; a focusing lens that focuses the laser light reflected on the mirror surface and irradiates the laser light onto a workpiece; and a control device that controls the galvanometer scanner so that the laser light reflected on the mirror surface is incident on a target irradiation position on the focusing lens that corresponds to a target scanning position on the workpiece.

5. The laser processing machine according to claim 4, characterized in that the control device translates the galvanometer mirror so that the laser light output from the oscillator is incident on a reflective surface among the mirror surfaces that has a surface orientation that allows the laser light to be reflected toward the target irradiation position on the focusing lens.

6. The laser processing machine according to claim 5, characterized in that the control device comprises: a reflecting surface position calculation unit that calculates the position of the reflecting surface; a galvanometer mirror position calculation unit that calculates the position of the galvanometer mirror at which the laser light output from the oscillator can be incident on the position of the reflecting surface calculated by the reflecting surface position calculation unit and generates a position command for the galvanometer scanner based on the position; and a galvanometer control unit that controls the galvanometer scanner based on the position command.

7. The laser processing machine according to claim 6, characterized in that the reflection surface position calculation unit determines a target reflection direction, which is the direction in which the laser light is reflected toward the target irradiation position, based on the target irradiation position, and calculates the position of the reflection surface based on the target reflection direction and the output direction of the laser light output from the oscillator.

8. A laser processing machine as described in any one of claims 4 to 7, further comprising: an optical component disposed between the mirror surface and the optical path of the focusing lens, for correcting the laser light reflected by the mirror surface.

9. The laser processing machine according to claim 8, characterized in that the optical components correct the laser light reflected by the galvanometer mirror so that the beam diameter of the laser light incident on the focusing lens becomes the same size as the beam diameter of the laser light output from the oscillator.

10. The laser processing machine according to claim 9, characterized in that the optical components, in addition to correcting the beam diameter of the laser light incident on the focusing lens, correct the laser light reflected by the galvanometer mirror so that the beam shape of the laser light incident on the focusing lens becomes circular.

11. A laser processing machine as described in any one of claims 4 to 10, characterized in that the galvano scanner is arranged so that the plane is inclined with respect to the output direction of the laser light output from the oscillator.

12. The laser processing machine according to claim 11, further comprising: a mounting table having a flat mounting surface for placing the workpiece on said mounting surface; and the galvanometer scanner is arranged so that the plane is inclined with respect to a direction perpendicular to the mounting surface.

Images