Laser processing machine

Abstract

A scanning galvanometer (20) has a galvanometer (21) having a mirror surface of a dome-like curved surface shape, and a driving section (22) having a plane (23) on which the galvanometer (21) is placed, and which causes the galvanometer (21) to translate in a direction parallel to the plane (23). The driving section (22) has an α-axis direction driving section (22α) which causes the galvanometer (21) to move in an α-axis direction parallel to the plane (23), and a β-axis direction driving section (22β) which causes the galvanometer (21) to move in a β-axis direction parallel to the plane (23) and different from the α-axis direction.

Description

Technical Field

[0001] This invention relates to a laser processing machine equipped with a scanning galvanometer. Background Technology

[0002] Due to the increasing demand for high-speed and high-precision laser processing in recent years, there is a need for high-speed driving and high-precision scanning positioning of scanning galvanometers. In scanning galvanometers that change the laser reflection direction by rotating the shaft supporting the planar galvanometer, the inherent vibration characteristics of the galvanometer cause surface tilting vibration, which tends to increase the deviation of the laser scanning position and deteriorate the processing accuracy. Patent Document 1 discloses a scanning galvanometer that uses a two-end support structure, where one end of the planar galvanometer is fixed to a motor and the other end is supported, thereby suppressing surface tilting vibration and balancing high-speed driving with improved scanning positioning accuracy.

[0003] Patent Document 1: Japanese Patent No. 6587603 Summary of the Invention

[0004] If the scanning galvanometer is driven at high speed, not only will the galvanometer's surface tilt vibration be generated, but also its torsional vibration. However, in the structure of the scanning galvanometer disclosed in Patent Document 1, it is difficult to suppress the torsional vibration of the galvanometer, thus resulting in the problem of being unable to suppress the deterioration of machining accuracy caused by torsional vibration.

[0005] The present invention was proposed in view of the above circumstances, and its purpose is to obtain a scanning galvanometer that balances high-speed driving and improved scanning positioning accuracy.

[0006] To address the aforementioned issues and achieve the objectives, the laser processing machine of the present invention includes an oscillator that outputs laser light. Furthermore, the laser processing machine of the present invention includes a scanning galvanometer, which comprises a mirror and a driving unit. The mirror has a dome-shaped curved surface, and the driving unit has a plane on which the mirror is mounted. The driving unit translates the mirror in a direction parallel to the plane. The scanning galvanometer is configured such that the plane is tilted relative to the output direction of the laser light output from the oscillator, and the scanning galvanometer reflects the laser light through the mirror surface. Additionally, the laser processing machine of the present invention is characterized by having a focusing lens and a control device. The focusing lens focuses the laser light reflected from the mirror surface to irradiate the workpiece, and the control device controls the scanning galvanometer so that the laser light reflected from the mirror surface is incident on the target irradiation position on the focusing lens corresponding to the target scanning position on the workpiece.

[0007] The effects of the invention

[0008] The scanning galvanometer of the present invention achieves the following effect: it can simultaneously achieve high-speed driving and improved scanning positioning accuracy. Attached Figure Description

[0009] Figure 1 This is a diagram showing the structure of the laser processing machine according to Embodiment 1.

[0010] Figure 2 This is an oblique view of the scanning galvanometer according to Embodiment 1.

[0011] Figure 3 This is a diagram showing the structure of the control device involved in Embodiment 1.

[0012] Figure 4 This is a diagram illustrating the Y-axis scanning of the laser in Embodiment 1.

[0013] Figure 5 This is a diagram illustrating the X-axis scanning of the laser in Embodiment 1.

[0014] Figure 6 From the +X axis direction Figure 4 A schematic diagram for observing the state.

[0015] Figure 7 This is a diagram showing the structure of the galvanometer position command generation unit according to Embodiment 1.

[0016] Figure 8 This is a diagram illustrating the method for determining the target position of the galvanometer involved in Embodiment 1.

[0017] Figure 9 This is a flowchart illustrating the laser scanning and positioning process involved in Implementation Method 1.

[0018] Figure 10 This is a diagram showing the structure of the laser processing machine according to Embodiment 2.

[0019] Figure 11 This is a diagram illustrating the correction of the laser beam diameter performed by optical components according to Embodiment 2.

[0020] Figure 12 This is a diagram illustrating an example of the hardware structure of the control device of the laser processing machine according to embodiments 1 to 2. Detailed Implementation

[0021] The scanning galvanometer and laser processing machine according to embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0022] Implementation Method 1

[0023] Figure 1 This is a diagram showing the structure of the laser processing machine 1 in Embodiment 1 of the present invention. Figure 1In this diagram, the X-axis, Y-axis, and Z-axis are three mutually perpendicular axes. The X-axis and Y-axis are horizontal axes. The Z-axis is the vertical axis. Furthermore, in... Figure 1 In this example, the X and Y axes are defined as horizontal axes, and the Z axis as a vertical axis. However, the X, Y, and Z axes only need to be three mutually perpendicular axes. The X and Y axes 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 and Z axes can be horizontal axes, and the X axis can be a vertical axis. Furthermore, the α and β axes are axes parallel to the plane 23 on which the galvanometer 21 is mounted, and are two mutually perpendicular axes. Figure 1 The diagram shows the case where the α-axis is parallel to the X-axis and the β-axis is parallel to the YZ plane.

[0024] Laser processing machine 1 processes workpiece 90 by irradiation with a laser. Laser processing machine 1 is, for example, a miniature laser processing machine. Workpiece 90 is, for example, a printed wiring board mounted on electronic equipment. Laser processing machine 1 includes an oscillator 10, a scanning galvanometer 20, a condenser lens 30, an XY stage 40, and a control device 50.

[0025] Oscillator 10 outputs laser 60a to scanning mirror 20.

[0026] The scanning galvanometer 20 includes a galvanometer 21 and a drive unit 22. The galvanometer 21 has a dome-shaped curved mirror surface through which the laser 60a output from the oscillator 10 is reflected. Furthermore, the dome-shaped curved mirror surface can be considered as a planar mirror surface with a specific orientation of its face depending on the location. Therefore, since the diameter of the laser beam is very small, the reflecting surface of the dome-shaped curved mirror surface through which the laser 60a output from the oscillator 10 is incident can also be considered as a planar mirror surface with a specific orientation of its face. Here, "reflecting surface" refers to a mirror surface on the galvanometer 21 with a diameter similar to that of the incident laser beam 60a.

[0027] The drive unit 22 has a plane 23 on which the galvanometer 21 is mounted, and the galvanometer 21 is translated in a direction parallel to the plane 23 by control following a position command. Figure 1 As shown, the scanning galvanometer 20 is preferably configured such that the plane 23 on which the galvanometer 21 is mounted is moderately tilted relative to the output direction of the laser 60a output from the oscillator 10, rather than parallel to it. For example, in the laser processing machine 1... Figure 1In the structure shown, the tilt of plane 23 relative to the output direction of laser 60a output from oscillator 10 can be defined by the direction of the β-axis. In this case, as an example of moderate tilt, plane 23 is configured to be tilted 135 degrees counterclockwise relative to the output direction of laser 60a (i.e., the +Y-axis direction), with the β-axis as the direction.

[0028] The reasons for preferring this configuration will be explained. For example, when the scanning galvanometer 20 is configured such that the β-axis direction of the plane 23 on which the galvanometer 21 is mounted is parallel to the output direction of the laser 60a, even if the galvanometer 21 is translated in the β-axis direction, the position of the reflecting surface into which the laser 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 along the Y-axis direction with the laser without changing the orientation of the reflecting surface, it is necessary to translate the galvanometer 21 in the β-axis direction by the same distance as the distance by which the irradiation position of the laser on the workpiece 90 is to be moved in the Y-axis direction.

[0029] In contrast, such as Figure 1 As shown, if the scanning galvanometer 20 is configured such that the plane 23 on which the galvanometer 21 is mounted is moderately tilted relative to the output direction of the laser 60a output from the oscillator 10, the change in the orientation of the reflecting surface can be controlled to scan the laser. Therefore, the distance the galvanometer 21 needs to translate in the β-axis direction is shorter than the distance required to move the laser irradiation position on the workpiece 90 in the Y-axis direction. Consequently, when scanning the workpiece 90 with the same distance at the same speed as the speed at which the galvanometer 21 is translated, the translation distance of the galvanometer 21 can be shortened when the plane 23 of the scanning galvanometer 20 is tilted relative to the output direction of the laser, compared to configuring the plane 23 of the scanning galvanometer 20 parallel to the output direction of the laser. Therefore, the time required for laser scanning is shortened, and higher speeds of drive can be achieved.

[0030] Furthermore, when the scanning galvanometer 20 is configured such that its plane 23 is parallel to the laser output direction, it is necessary to ensure that the movable range of the galvanometer 21 can be translated without interference with the surrounding area, as the same range as the processing area on the workpiece 90 where the laser scans. Conversely, when the scanning galvanometer 20 is configured such that its plane 23 is tilted relative to the laser output direction, it is sufficient to ensure that the movable range is smaller than the processing area on the workpiece 90 where the laser scans. Therefore, compared to configuring the scanning galvanometer 20 such that its plane 23 is parallel to the laser output direction, configuring the scanning galvanometer 20 such that its plane 23 is tilted relative to the laser output direction allows for unrestricted design of the laser processing machine mechanism.

[0031] Figure 2This is an oblique view of the scanning galvanometer 20. (Example) Figure 2 As shown, the drive unit 22 has: an α-axis drive unit 22α, which moves the galvanometer 21 in the α-axis direction parallel to the plane 23 on which the galvanometer 21 is mounted; and a β-axis drive unit 22β, which moves the galvanometer 21 in the β-axis direction parallel to the plane 23 on which the galvanometer 21 is mounted and orthogonal to the α-axis direction.

[0032] Although Figure 2 In this configuration, a galvanometer 21 is mounted on a plane 23 on the α-axis drive unit 22α. However, the order of the α-axis drive unit 22α and the β-axis drive unit 22β can be reversed, with the galvanometer 21 mounted on a plane on the β-axis drive unit 22β. Alternatively, instead of directly mounting the galvanometer 21 on a plane on the α-axis drive unit 22α or the β-axis drive unit 22β, the galvanometer 21 can be mounted on a top worktable having a plane including both the α-axis and β-axis directions. The galvanometer 21 is translated by driving the top worktable with the α-axis drive unit 22α and the β-axis drive unit 22β.

[0033] By linking the α-axis drive unit 22α and the β-axis drive unit 22β, the galvanometer 21 can be translated to any position in a two-dimensional direction including the α-axis and β-axis directions. Furthermore, the α-axis and β-axis do not necessarily need to be orthogonal; they only need to be coordinate systems that can determine the position in the two-dimensional direction that translates the galvanometer 21. That is, the α-axis and β-axis directions only need to be parallel to the plane 23 on which the galvanometer 21 is mounted and different from each other.

[0034] The drive unit 22 can be, for example, a two-axis linear actuator driven by an electric motor. When the laser 60c scans the workpiece 90 in only one dimension, the drive unit 22 does not necessarily need to have a two-axis drive unit; it can be composed of only a one-axis drive unit. Furthermore, without separately distinguishing between the α-axis drive unit 22α and the β-axis drive unit 22β, they will be collectively referred to as the drive unit 22.

[0035] return Figure 1 The condenser lens 30 is an fθ lens (F-Theta lens) that focuses the laser 60b reflected from the dome-shaped curved surface of the galvanometer 21, irradiating the workpiece 90 on the XY stage 40 with laser 60c perpendicularly. The position of the laser 60c irradiating the workpiece 90 is determined by the position of the laser 60b incident on the condenser lens 30. That is, the position of the laser 60b incident on the condenser lens 30 corresponds one-to-one with the position of the laser 60c irradiating the workpiece 90.

[0036] The XY stage 40 places the workpiece 90 on the mounting surface 41 and moves the workpiece 90 in a two-dimensional direction including the X-axis and Y-axis by control according to position commands. When the processing area for the workpiece 90 is small, and the laser 60c can scan the processing area solely by driving the scanning galvanometer 20, it is not necessary to use the XY stage 40 to move the workpiece 90. The workpiece 90 can also be placed on a fixed stage (not shown) with a fixed mounting surface instead of the XY stage 40. The XY stage 40 and the fixed stage are the same in that they both have a planar mounting surface for placing the workpiece 90, but they differ in that this mounting surface can be moved. That is, the XY stage 40 and the fixed stage are platforms for placing the workpiece 90 on the mounting surface.

[0037] Furthermore, from the perspective of laser scanning and positioning accuracy, such as Figure 1 As shown, the scanning galvanometer 20 is preferably configured such that the plane 23 on which the galvanometer 21 is mounted is perpendicular to the mounting surface 41 on which the workpiece 90 is mounted (in... Figure 1 The axis (Z-axis) is slightly tilted rather than parallel. For example, in laser processing machine 1... Figure 1 In the case of the structure shown, the inclination of plane 23 relative to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is placed can be defined by the direction of the β axis. In this case, as an example of moderate inclination, plane 23 is configured to be inclined counterclockwise by 45 degrees to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is placed (i.e., the Z-axis direction) along the β axis.

[0038] The reasons for preferring the above configuration will be explained. For example, in Figure 1 In the case where the scanning galvanometer 20 is configured such that the β-axis direction of the plane 23 on which the galvanometer 21 is mounted is parallel to the Z-axis direction, compared to the case where the β-axis direction of the plane 23 is tilted relative to the Z-axis direction, the rate of change in the orientation of the reflecting surface is greater relative to the distance the galvanometer is translated in the β-axis direction. Therefore, even if the galvanometer is only slightly translated in the β-axis direction (i.e., the Z-axis direction), the orientation of the reflecting surface changes significantly, and consequently, the scanning position of the laser also changes significantly. Thus, the scanning positioning accuracy of the laser is easily affected by the positioning error of the galvanometer.

[0039] In contrast, when the scanning galvanometer 20 is configured such that the β-axis direction of the plane 23 on which the galvanometer 21 is mounted is slightly tilted relative to the Z-axis direction, compared to the case where the β-axis direction of the plane 23 is parallel to the Z-axis direction, the rate of change in the orientation of the reflecting surface relative to the distance the galvanometer is translated in the β-axis direction is smaller. Therefore, the laser scanning positioning accuracy is less affected by the positioning error of the galvanometer. Thus, the configuration of the scanning galvanometer 20 with the plane 23 on which the galvanometer 21 is mounted being slightly tilted relative to the direction perpendicular to the mounting surface 41 on which the workpiece 90 is mounted facilitates high-precision laser scanning.

[0040] The control device 50 controls the entire laser processing machine 1. Specifically, the control device 50 controls the operation of the oscillator 10, the scanning galvanometer 20, and the XY stage 40. Specifically, the control device 50 moves the workpiece 90 via the XY stage 40 so that the processing area on the workpiece 90 enters the scannable range of the laser 60c. Then, according to the target position on the workpiece 90 to be irradiated by the laser 60c, the control device 50 controls the scanning galvanometer 20 so that the laser 60c is incident on the target scanning position. That is, the control device 50 controls the scanning galvanometer 20 so that the laser 60b is incident on the irradiation position on the focusing lens 30 corresponding to the target scanning position, i.e., the target irradiation position. Figure 3 This diagram shows the structure of the control device 50. The control device 50 includes an instruction generation unit 51 for generating various instructions, a laser control unit 55, a galvanometer control unit 56, and an XY stage control unit 57.

[0041] The instruction generation unit 51 includes: an XY stage position instruction generation unit 52, which generates position instructions for the XY stage 40; a galvanometer position instruction generation unit 53, which generates position instructions for the scanning galvanometer 20; and a laser output instruction generation unit 54, which generates laser output instructions. The laser control unit 55 controls the oscillator 10 according to the laser output instructions generated by the laser output instruction generation unit 54. The galvanometer control unit 56 controls the scanning galvanometer 20 according to the position instructions generated by the galvanometer position instruction generation unit 53. The galvanometer control unit 56 controls the translation of the galvanometer 21 implemented by the drive unit 22, and positions the galvanometer 21. The XY stage control unit 57 controls the movement of the XY stage 40 according to the position instructions generated by the XY stage position instruction generation unit 52, and positions the workpiece 90 placed on the XY stage 40.

[0042] Next, the operation of laser processing machine 1 will be explained.

[0043] The mirror surface of galvanometer 21 has a dome-shaped curved surface. Therefore, by translating galvanometer 21, the position of the reflecting surface incident on the laser 60a output from oscillator 10 can be controlled, thereby changing the orientation of the reflecting surface (the direction the reflecting surface faces) relative to the incident direction, and enabling the laser 60a to be reflected in any direction. As an example, the operation when the irradiation position on the workpiece 90 is moved in the Y-axis direction will be explained.

[0044] Figure 4 This is a diagram used to illustrate the scanning of a laser along the Y-axis. Figure 4 It schematically shows that in Figure 1 In the laser processing machine 1 shown, the laser reflection direction changes corresponding to the position where the galvanometer 21 is translated in the β-axis direction, causing the irradiation position on the workpiece 90 to move in the Y-axis direction. Furthermore, a case is shown where the XY stage 40 is not driven, and the position of the workpiece 90 is fixed.

[0045] Figure 4 (a) shows the position of the laser 61a output from the oscillator 10 in the horizontal direction (+Y axis direction) when it is reflected by the reflecting surface M1 on the galvanometer 21 in the vertical direction (-Z axis direction). Figure 4 (b) shows the galvanometer 21 being moved from Figure 4 The state of (a) is translated in the +β axis direction, and the reflection direction and irradiation position of the laser 62a output from the oscillator 10 in the horizontal direction (+Y axis direction) is reflected by the reflecting surface M2 on the galvanometer 21. Figure 4 (c) shows the galvanometer 21 being moved from Figure 4 The state of (a) is translated in the -β axis direction, and the reflection direction and irradiation position of the laser 63a output from the oscillator 10 in the horizontal direction (+Y axis direction) when it is reflected by the reflecting surface M3 on the galvanometer 21.

[0046] If the galvanometer 21 is moved from Figure 4 The position shown in (a) is translated along the +β axis to Figure 4 As shown in (b), the position of the laser incident reflection surface on galvanometer 21 also moves relatively from reflection surface M1 to reflection surface M2. Compared to reflection surface M1, the orientation of reflection surface M2 is tilted towards the +Y axis. Therefore, compared to laser 61b, the direction of reflected light from laser 62b is tilted towards the +Y axis, and thus the position irradiating the condenser lens 30 moves from L1 to L2 in the +Y axis direction. As a result, the irradiation position of laser 62c irradiating the workpiece 90 also moves from W1 to W2 in the +Y axis direction.

[0047] When the galvanometer 21 is translated in the -β axis direction, the operation becomes the opposite of the above. That is, if the galvanometer 21 is moved from... Figure 4 The position shown in (a) is translated along the -β axis to Figure 4 As shown in (c), the position of the laser incident reflection surface on galvanometer 21 also moves relatively from reflection surface M1 to reflection surface M3. Compared to reflection surface M1, the orientation of reflection surface M3 is tilted towards the -Y axis. Therefore, compared to laser 61b, the direction of reflected light from laser 63b is tilted towards the -Y axis, and thus the position irradiating the condenser lens 30 moves from L1 to L3 in the -Y axis direction. As a result, the irradiation position of laser 63c irradiating the workpiece 90 also moves from W1 to W3 in the -Y axis direction.

[0048] Furthermore, as another example, the operation of moving the irradiation position on the workpiece 90 in the X-axis direction will be explained. Figure 5 This is a diagram used to illustrate the X-axis scanning of a laser. Figure 5 It schematically shows that in Figure 1 In the laser processing machine 1 shown, the laser reflection direction changes corresponding to the position where the galvanometer 21 is translated in the α-axis direction, causing the irradiation position on the workpiece 90 to move in the X-axis direction. Furthermore, a case is shown where the XY stage 40 is not driven, and the position of the workpiece 90 is fixed.

[0049] Figure 5 (a) shows the relationship with Figure 4 (a) The same state. Figure 5 (b) shows the galvanometer 21 being moved from Figure 5 The state of (a) is translated in the +α axis direction (i.e., the +X axis direction), and the reflection direction and irradiation position of the laser 64a output from the oscillator 10 in the horizontal direction (+Y axis direction) when it is reflected by the reflecting surface M4 on the galvanometer 21. Figure 5 (c) shows the galvanometer 21 being moved from Figure 5 The state of (a) is translated in the -α axis direction (i.e., the -X axis direction), and the reflection direction and irradiation position of the laser 65a output from the oscillator 10 in the horizontal direction (+Y axis direction) when it is reflected by the reflecting surface M5 on the galvanometer 21.

[0050] If the galvanometer 21 is moved from Figure 5 The position shown in (a) is translated along the +α axis to Figure 5As shown in (b), the position of the laser incident reflection surface on galvanometer 21 also moves relatively from reflection surface M1 to reflection surface M4. Compared to reflection surface M1, the orientation of reflection surface M4 is tilted towards the -X-axis direction. Therefore, compared to laser 61b, the direction of reflected light from laser 64b is tilted towards the -X-axis direction, and thus the position irradiating the condenser lens 30 moves from L1 to L4 in the -X-axis direction. As a result, the irradiation position of laser 64c irradiating the workpiece 90 also moves from W1 to W4 in the -X-axis direction.

[0051] When the galvanometer 21 is translated in the -α axis direction, the operation becomes the opposite of the above. That is, if the galvanometer 21 is moved from... Figure 5 The position shown in (a) is translated along the -α axis to Figure 5 As shown in (c), the position of the laser incident reflection surface on galvanometer 21 also moves relatively from reflection surface M1 to reflection surface M5. Compared to reflection surface M1, the orientation of reflection surface M5 is tilted towards the +X axis. Therefore, compared to laser 61b, the direction of reflected light from laser 65b is tilted towards the +X axis, and thus the position irradiating the condenser lens 30 moves from L1 to L5 in the +X axis direction. As a result, the irradiation position of laser 65c irradiating the workpiece 90 also moves from W1 to W5 in the +X axis direction.

[0052] Furthermore, by linking the α-axis drive unit 22α and the β-axis drive unit 22β, the galvanometer 21 is translated to any position in a two-dimensional direction including the α-axis and β-axis directions. This allows the laser output from the oscillator 10 to be incident on a reflecting surface with a specific orientation in the dome-shaped curved mirror, thereby reflecting the laser in any direction. As a result, the laser can be directed to any position on the condenser lens 30. Consequently, the laser can be directed to any position on the workpiece 90.

[0053] As described above, the control device 50 controls the position of the galvanometer 21 to be translated, so that the laser output from the oscillator 10 is reflected by the reflecting surface with a specific orientation, thereby adjusting the position of the laser incident on the condenser lens 30. Furthermore, since the laser irradiates the workpiece 90 perpendicularly from the condenser lens 30, the position of the laser incident on the workpiece 90 can be adjusted simply by adjusting the position of the laser incident on the condenser lens 30.

[0054] Next, the method for controlling the position of the galvanometer translation will be explained. As an example, using... Figure 6 For example Figure 4 The following explanation illustrates the situation where the laser scans along the Y-axis. Figure 6 (a) is from the +X axis direction. Figure 4A schematic diagram for observing the state of (a). Figure 6 (b) is from the +X axis direction. Figure 4 A schematic diagram for observing state (b). For simplicity, an example is provided below. Figure 6 The described galvanometer 21a has a hemispherical mirror surface. Furthermore, Figure 6 The galvanometer 21a described only shows the vicinity of laser incidence. Furthermore, in the case where the galvanometer 21a has a hemispherical mirror surface, as an example, the position of the galvanometer 21a can be indicated by the position of the center point of the hemispherical mirror surface, showing that... Figure 6 In state (a), the center point of the hemispherical mirror surface of galvanometer 21a is located at P1. Figure 6 In state (b), the center point of the hemispherical mirror of galvanometer 21a is located at P2.

[0055] Figure 6 (a) shows the state in which laser 61a output from oscillator 10 in the horizontal direction (+Y axis direction) is reflected by reflector M1 in the vertical direction (-Z axis direction). Figure 6 In case (a), according to the law of reflection, the angle of incidence θ1 and the angle of reflection θ1' are equal, therefore the angle of incidence θ1 = the angle of reflection θ1' = 45 degrees. The orientation of the reflecting surface is equal to the direction of the normal to the reflecting surface, and therefore can be represented by the direction of the normal to the reflecting surface. Figure 6 In case (a), if the orientation of the reflecting surface M1, i.e. the direction of the normal h1 of the reflecting surface M1, is represented by the direction θh1 shown in the figure, then θh1 is equal to the incident angle θ1, which is 45 degrees. Therefore, the orientation of the reflecting surface M1 is θh1 = 45 degrees.

[0056] In other words, by directing the laser 61a output from the oscillator 10 in the horizontal direction (+Y axis direction) onto the reflecting surface M1 with a normal direction of θh1=45 degrees, the incident angle θ1=normal direction θh1=45 degrees and the reflection angle θ1'=incident angle θ1=45 degrees, thus the laser 61b can be reflected in the vertical direction (-Z axis direction).

[0057] Figure 6 (b) illustrates the following situation, namely, when galvanometer 21a is moved from... Figure 6When the position of the galvanometer 21a shown in (a) is translated in the +β axis direction, the position of the center point of the hemispherical mirror of the galvanometer 21a moves from P1 to P2. The position of the reflecting surface of the laser 62a output from the oscillator 10 in the horizontal direction (+Y axis direction) moves from the reflecting surface M1 with the normal h1 in the direction θh1 to the reflecting surface M2 with the normal h2 in the direction θh2. As a result, the reflection direction of the laser changes from laser 61b to laser 62b. Consequently, the position irradiated onto the condenser lens 30 moves from L1 to L2 in the +Y axis direction, and the irradiation position on the workpiece 90 also moves from W1 to W2 in the +Y axis direction. At this time, the relationship becomes incident angle θ2 = normal direction θh2, and reflection angle θ2' = incident angle θ2.

[0058] In other words, by translating the galvanometer 21a so that the center point of the hemispherical mirror surface is P2, the laser 62a output from the oscillator 10 in the horizontal direction (+Y axis direction) is incident on the reflecting surface M2 with the normal h2 in the direction of θh2. This allows the incident light, i.e., the laser 62a, to be reflected in the direction of the reflected light, i.e., the laser 62b, which satisfies the relationship that the incident angle θ2 = the normal direction θh2 and the reflection angle θ2' = the incident angle θ2. As a result, the laser 62b can be directed to the target irradiation position L2 on the condenser lens 30, and the laser 62c can be directed to the target irradiation position W2 on the workpiece 90.

[0059] Therefore, in order to set the position W2 on the workpiece 90 as the target scanning position and direct the laser to that target scanning position W2, it is only necessary to translate the galvanometer 21a so that the center point of the hemispherical mirror of the galvanometer 21a is at position P2. Furthermore, in Figure 6 In the example, the case where the galvanometer 21a has a hemispherical mirror surface was described, but the same applies to the case where the galvanometer 21a has a mirror surface with a shape that is a portion of a sphere.

[0060] As described above, by calculating the position of the reflecting surface on the galvanometer corresponding to the target scanning position on the workpiece 90, which has a surface capable of reflecting towards the target irradiation position on the condenser lens 30, and by calculating the position of the galvanometer that allows the laser output from the oscillator to be incident on the reflecting surface, the position of the galvanometer can be controlled so that the laser irradiates the target irradiation position on the condenser lens 30. As a result, the laser can be made to scan the target scanning position on the workpiece 90.

[0061] Figure 7This diagram illustrates the structure of the galvanometer position command generation unit 53. The galvanometer position command generation unit 53 includes a reflector position calculation unit 58 and a galvanometer position calculation unit 59. The reflector position calculation unit 58 obtains the set target scanning position from an input unit (not shown), calculates the target illumination position on the condenser lens 30 corresponding to the target scanning position, and calculates the position of the reflector surface on the galvanometer 21a, which has a surface capable of reflecting towards the target illumination position. Based on the position of the reflector surface on the galvanometer 21a calculated by the reflector position calculation unit 58, the galvanometer position calculation unit 59 calculates the position of the galvanometer 21a that allows the laser output from the oscillator 10 to be incident on the reflector surface, and generates a corresponding position command based on this position. The galvanometer position command generation unit 53 generates a position command for the scanning galvanometer 20 with this structure.

[0062] As an example, using Figure 8 For the current galvanometer 21a at Figure 6 When the position of the center point P1 of the galvanometer 21a shown in (a) is determined, the next target position of the galvanometer 21a is calculated. Figure 6 The position of the center point P2 of the galvanometer 21a shown in (b) will be explained.

[0063] Figure 8 The position of the galvanometer 21a relative to the incident light shows that... Figure 6 (a) is the same state. That is, the following situation is shown, that is, the current center point of the galvanometer 21a is located at P1, and if laser 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 61b reflected by the reflecting surface M1 illuminates the position L1 on the condenser lens 30.

[0064] In the above-described situation, the reflector position calculation unit 58 first calculates the coordinate position information of the next target illumination position L2 on the condenser lens 30 based on the set next target scanning position W2. Based on the coordinate position information of the reflector M1 and the coordinate position information of the target illumination position L2, it calculates... Figure 8 The direction of reflection of the next target reflected light, i.e., laser 62b, is shown. That is, the direction of reflection towards the next target illumination position L2 on the focusing lens 30 is determined, i.e., the target reflection direction.

[0065] Next, the reflecting surface position calculation unit 58 calculates the orientation of the surface required to reflect the laser 61a in the direction of laser 62b (i.e., the target reflection direction) when laser 61a is incident on galvanometer 21a, based on the incident direction of laser 61a and the reflection direction of laser 62b. This is equivalent to calculating the midpoint of the angle between laser 61a and laser 62b according to the law of light reflection. Figure 8The diagram shows that the direction of line h2' is the midpoint of the angle between laser 61a and laser 62b. That is, the direction of line h2' is the orientation of the surface required to reflect laser 61a towards laser 62b when laser 61a is incident on galvanometer 21a.

[0066] Next, the reflecting surface position calculation unit 58 calculates the position of the reflecting surface M2, which has the orientation of the surface required for reflection from the surface on the galvanometer 21a toward the direction of the laser 62b. For example... Figure 8 As shown, this can be solved by taking the line h2' after it is moved parallel to the center point P1 of the galvanometer 21a as the normal h2", and taking the point where the normal h2" intersects the surface of the galvanometer 21a as the position of the reflecting surface M2.

[0067] Next, the galvanometer position calculation unit 59 determines the target position, i.e., the position of the center point P2, that causes the galvanometer 21a to be translated. This can be solved in the following way. Figure 8 As shown, the point where the straight line extending from the center point of the reflecting surface M2 in the +β axis direction intersects the extension line of the laser 61a is designated as P3. When the vector with the center point of the reflecting surface M2 as the starting point and P3 as the ending point is designated as V1, the position of the ending point of the vector V2 after moving the starting point of the vector V1 to the center point P1 of the galvanometer 21a is the target position for translating the galvanometer 21a, i.e., the position of the center point P2.

[0068] By translating galvanometer 21a so that the position of the center point of galvanometer 21a is the same as the position of the center point P2 of galvanometer 21a as determined above, thus... Figure 8 The reflective surface M2 is moved to position P3, and laser 61a is incident on the moved reflective surface M2. The reflective surface M2 has an orientation that allows it to reflect in the direction of laser 62b; therefore, laser 61a incident on the reflective surface M2 is reflected in the direction of laser 62b, and laser 62b irradiates the target irradiation position L2 on the focusing lens 30. As a result, laser 62c can scan the workpiece 90 at position W2.

[0069] By controlling the position of the galvanometer 21a in the β-axis direction as described above, the laser can be directed to any position on the condenser lens 30 in the Y-axis direction, resulting in the laser scanning any position on the workpiece 90 in the Y-axis direction. Similarly, when scanning in the X-axis direction, by controlling the position of the galvanometer 21a in the α-axis direction, the laser can be directed to any position on the condenser lens 30 in the X-axis direction, resulting in the laser scanning any position on the workpiece 90 in the X-axis direction. Furthermore, by combining the above controls to control the positions of the galvanometer 21a in both the α-axis and β-axis directions, the laser can be directed to any position on the condenser lens 30, resulting in the laser scanning any position on the workpiece 90.

[0070] In addition, Figure 8 In this paper, an example is given of calculating the position of the reflecting surface M2 and the target position for translating the galvanometer in a geometric manner when the galvanometer 21a has a hemispherical mirror surface, but the method is not limited to this. For example, not only the case where the galvanometer 21a has a hemispherical mirror surface, but also the case where the mirror has a shape after truncating a part of a sphere, and the case where the mirror has a dome-shaped curved surface, can be included. The 3D shape of the galvanometer used and the positional relationship between the galvanometer and the oscillator can be modeled and pre-registered in a storage unit (not shown). The position of the reflecting surface M2 on the galvanometer 21a can be calculated by the reflecting surface position calculation unit 58 using this model, and the target position for translating the galvanometer 21a can be calculated by the galvanometer position calculation unit 59.

[0071] Next, the process of laser scanning and positioning will be explained. Figure 9 This is a flowchart illustrating the laser scanning and positioning process. First, the reflective surface position calculation unit 58 obtains the target scanning position of the laser for the workpiece 90 (step 1). Specifically, the reflective surface position calculation unit 58 obtains the set target scanning position from the input unit (not shown). Alternatively, a storage unit (not shown) can pre-store multiple target scanning positions required for laser processing to apply the target processing shape to the workpiece 90, and the reflective surface position calculation unit 58 obtains the required target scanning position from the storage unit each time.

[0072] Next, the reflector position calculation unit 58 calculates the next target illumination position on the condenser lens 30 based on the obtained target scanning position, and calculates the position of the next reflector on the laser incident galvanometer 21 (step 2). Specifically, by... Figure 8 The method described herein is used to calculate the position of the reflecting surface, which has the orientation of a surface capable of reflecting the light towards the next target illumination position on the condenser lens 30.

[0073] Next, the galvanometer position calculation unit 59 calculates the next target position of the translated galvanometer 21 (step 3). Specifically, the galvanometer position calculation unit 59 calculates the next target position of the translated galvanometer 21 by... Figure 8 The method described above is used to calculate the position of the galvanometer 21, which enables the laser to be incident on the position of the reflecting surface calculated in step 2. That is, the position of the galvanometer 21 in the α-axis direction and the β-axis direction are controlled, and the position of the galvanometer 21 is calculated so that the position of the reflecting surface calculated in step 2 reaches the trajectory of the laser output from the oscillator 10.

[0074] Next, the galvanometer position calculation unit 59 generates and outputs a position command for the scanning galvanometer 20 based on the target position of the galvanometer 21 calculated in step 3 (step 4). Next, the galvanometer control unit 56 controls the scanning galvanometer 20 according to the position command for the scanning galvanometer 20, causing the galvanometer 21 to translate towards the target position of the galvanometer 21 (step 5). Then, the laser output from the oscillator 10 is reflected by the reflective surface located at the position calculated in step 2, and the laser after passing through the target irradiation position on the condenser lens 30 irradiates the target scanning position on the workpiece 90 (step 6).

[0075] Specifically, the result of step 5 is that, along with the translation of the galvanometer 21, the position of the reflecting surface from which the laser output from the oscillator 10 is incident moves to the position of the reflecting surface calculated in step 2. The orientation of the reflecting surface changes, thereby adjusting the reflection direction of the laser, and the irradiation position of the laser on the condenser lens 30 moves towards the target irradiation position. If the laser is irradiated towards the target irradiation position on the condenser lens 30, the laser is focused by the condenser lens 30 and irradiated towards the target scanning position on the workpiece 90.

[0076] By changing the target scanning position of the laser on the workpiece 90 while repeating the processes described in steps 1 to 6 as above, the workpiece 90 can be laser-processed as desired.

[0077] As described above, the scanning galvanometer in this embodiment translates the galvanometer with a dome-shaped curved surface, thereby reflecting the laser in any direction. Therefore, unlike conventional scanning galvanometers, it does not rotate the planar galvanometer, thus avoiding surface tilting vibration and torsional vibration. This allows for both high-speed driving and improved scanning positioning accuracy.

[0078] Furthermore, in conventional laser processing machines using scanning galvanometers, multiple planar galvanometers are required to perform laser scanning at any position. In addition, the scanning positioning accuracy is affected by the manufacturing errors and thermal deformation of each galvanometer, resulting in a deterioration in processing accuracy. In contrast, the laser processing machine in this embodiment only requires one galvanometer, which can be achieved with fewer galvanometers than before. Therefore, it can also suppress the impact on processing accuracy caused by the manufacturing errors and thermal deformation of the galvanometer.

[0079] Implementation Method 2

[0080] When laser light is reflected by a planar mirror, as in conventional scanning galvanometers, the reflected laser light propagates in the optical path without diffusion, just like the incident light. In contrast, when laser light is reflected by a dome-shaped curved mirror, as in Embodiment 1, the reflected laser light propagates in the optical path with a diffusion angle corresponding to the curvature of the reflecting surface. Therefore, proportional to the size of this diffusion angle and the distance between the galvanometer and the condenser lens, the beam diameter of the laser light reaching the condenser lens becomes larger than the beam diameter of the laser light output from the oscillator.

[0081] Furthermore, when the galvanometer has a hemispherical mirror surface, the curvature is the same in any direction on the mirror surface. Therefore, the reflected laser beam shape becomes the same as the incident light beam shape. However, when the galvanometer has a mirror surface with a curvature that varies depending on the direction on the mirror surface, the reflected laser beam shape is distorted into a shape different from the original laser beam shape. Therefore, even if the laser beam shape output from the oscillator is circular, if it is reflected by a galvanometer with a mirror surface having a curvature that varies depending on the direction on the mirror surface, the reflected laser beam shape will be distorted into an elliptical shape.

[0082] As described above, the beam diameter and shape of the laser change before and after reflection by the galvanometer, which may lead to a decrease in the focusing power of the laser passing through the condenser lens 30, thus reducing processing accuracy. Therefore, in Embodiment 2, a laser processing machine is described that can correct the beam diameter and shape of the reflected laser and suppress the decrease in the focusing power of the laser passing through the condenser lens 30. Descriptions of parts identical to those in Embodiment 1 are omitted; descriptions of parts different from those in Embodiment 1 are provided.

[0083] Figure 10 This diagram illustrates the structure of the laser processing machine 1A according to Embodiment 2. The structures of the scanning galvanometer and control device according to Embodiment 2 are the same as those of the scanning galvanometer and control device in Embodiment 1, therefore, descriptions are omitted. Figure 10The difference from embodiment 1 is that an optical component 70 is provided between the mirror surface of the galvanometer 21 and the optical path of the condenser lens 30. The optical component 70 corrects the laser 60d reflected by the mirror surface of the galvanometer 21 and irradiates the condenser lens 30 with the corrected laser 60e.

[0084] Figure 11 This diagram serves as an example to illustrate the correction of the laser beam diameter performed by the optical component 70 in the case of using a galvanometer 21a with a hemispherical mirror surface. Figure 11 As shown, the laser 60d, reflected by the galvanometer 21a with a hemispherical mirror surface, diffuses and propagates towards the optical component 70. Consequently, the beam diameter of the laser 60d at the point of arrival at the optical component 70 becomes larger than the beam diameter of the laser 60a output from the oscillator 10.

[0085] Optical component 70 corrects the laser 60d reflected by galvanometer 21a so that the beam diameter of the laser 60e incident on condenser lens 30 after passing through optical component 70 becomes the same as the beam diameter of the laser 60a output from oscillator 10. As a result, with laser 60e of the same beam diameter as the laser 60a output from oscillator 10 incident on condenser lens 30, the reduction in the focusing ability of laser 60e passing through condenser lens 30 can be suppressed. Consequently, processing defects caused by the reduction in laser focusing ability can be reduced. Furthermore, without using such optical component 70, the focusing ability of the laser can be corrected by pre-adjusting the refractive index of condenser lens 30 to take into account the magnification rate of the laser beam diameter reflected by galvanometer 21a.

[0086] exist Figure 11 In the example described, the case of using a galvanometer 21a with a hemispherical mirror surface was illustrated. However, when a galvanometer 21 is used with a mirror surface whose curvature varies depending on the direction on the mirror surface, not only the diameter of the laser beam but also the shape of the laser beam changes before and after reflection from the galvanometer 21. Therefore, even if the laser beam output from the oscillator 10 has a circular beam shape, if it is reflected by the galvanometer 21 with a mirror surface whose curvature varies depending on the direction on the mirror surface, the shape of the reflected laser beam will be distorted into an elliptical shape.

[0087] In this case, the optical component 70 can correct not only the laser beam diameter but also the laser beam shape. In this case, the optical component 70 corrects not only the laser beam diameter but also the laser beam 60d reflected by the galvanometer 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 with the corrected beam diameter and shape is incident on the condenser lens 30, thus further suppressing the reduction in the focusing ability of the laser beam passing through the condenser lens 30.

[0088] As described above, the laser processing machine 1A in this embodiment corrects the beam diameter and beam shape of the laser by the optical component 70 so that the appropriate laser beam is incident on the condenser lens 30, thereby suppressing the reduction of the focusing ability of the laser beam passing through the condenser lens 30. As a result, processing defects caused by the reduction of the focusing ability of the laser beam can be reduced.

[0089] Next, the hardware structure of the control device 50 according to embodiments 1 to 2 will be described. Figure 12 This is a diagram illustrating an example of the hardware structure of the control device 50 of the laser processing machines 1 and 1A according to embodiments 1 and 2. Figure 12 The hardware structure is shown in the case where the function of the control device 50 is implemented by using hardware that executes the program.

[0090] Processor 101 is a CPU (Central Processing Unit). Processor 101 may also be a processing device, a computing device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor). Memory 102 is RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), or EEPROM (Electrically Erasable Programmable Read Only Memory).

[0091] Storage device 103 is either an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The program that enables the computer to function as a control device 50 is stored in storage device 103. Processor 101 reads the program stored in storage device 103 into memory 102 and executes it.

[0092] The program can also be stored on a storage medium that can be read by a computer system. The control device 50 can also store the program recorded on the storage medium into the memory 102. The storage medium can be a removable storage medium as a floppy disk or flash memory as semiconductor memory. The program can also be installed into the computer system from other computer or server devices via a communication network.

[0093] The functions of the instruction generation unit 51, laser control unit 55, galvanometer control unit 56, and XY stage control unit 57 are implemented through a combination of processor 101 and software. These functions can also be implemented through a combination of processor 101 and firmware, or through a combination of processor 101, software, and firmware. The software or firmware is described as a program and stored in storage device 103.

[0094] The interface circuit 104 sends signals to the hardware-connected devices, namely the oscillator 10, the scanning mirror 20, and the XY stage 40.

[0095] The structures shown in the above embodiments represent one example of the content of the present invention. The structures of each embodiment can be combined with other known technologies. The structures of each embodiment can also be appropriately combined with each other. Parts of the structure of each embodiment can be omitted or modified without departing from the spirit of the present invention.

[0096] Explanation of the label

[0097] 1. 1A Laser Processing Machine, 10 Oscillator, 20 Scanning Galvanometer, 21, 21a Galvanometer, 22 Drive Unit, 22α α-axis Drive Unit, 22β β-axis Drive Unit, 23 Plane for Mounting Galvanometer, 30 Condensing Lens, 40 XY Stage, 41 Mounting Surface, 50 Control Device, 51 Command Generation Unit, 52 XY Stage 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 Stage Control Unit, 58 Reflector Surface Position Calculation Unit, 59 Galvanometer position calculation unit, 60a, 60b, 60c, 60d, 60e, 61a, 61b, 61c, 62a, 62b, 62c, 63a, 63b, 63c, 64a, 64b, 64c, 65a, 65b, 65c Laser, 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 illumination position, M1, M2, M3, M4, M5 Reflecting surface, P1, P2 Position of the center point of the hemispherical mirror of the galvanometer, P3 Position of the endpoint of vector V1, V1, V2 Vectors, W1, W2, W3, W4, W5 Target scanning position.

Claims

1. A laser processing machine, characterized in that, have: An oscillator that outputs laser light; A scanning galvanometer has a galvanometer and a driving unit. The galvanometer has a dome-shaped curved mirror surface, and the driving unit has a plane on which the galvanometer is mounted. The driving unit causes the galvanometer to translate in a direction parallel to the plane. The scanning galvanometer is configured such that the plane is tilted relative to the output direction of the laser output from the oscillator. The scanning galvanometer reflects the laser through the mirror surface. A focusing lens that focuses the laser light reflected from the mirror surface and illuminates the workpiece with the laser light; and A control device controls the scanning galvanometer so that the laser reflected from the mirror is incident on the target irradiation position on the condenser lens corresponding to the target scanning position on the workpiece.

2. The laser processing machine according to claim 1, characterized in that, The drive unit has: An α-axis driving unit that moves the galvanometer in the α-axis direction, which is parallel to the plane; and The β-axis drive unit moves the galvanometer in a β-axis direction that is parallel to the plane and different from the α-axis direction.

3. The laser processing machine according to claim 1, characterized in that, The galvanometer has a mirror surface that is shaped like a portion of a sphere.

4. The laser processing machine according to any one of claims 1 to 3, characterized in that, The control device translates the galvanometer so that the laser output from the oscillator is incident on a reflecting surface in the mirror that has an orientation capable of reflecting towards the target irradiation position on the condenser lens.

5. The laser processing machine according to claim 4, characterized in that, The control device has: A reflective surface position calculation unit calculates the position of the reflective surface; The galvanometer position calculation unit calculates the position of the galvanometer that enables the laser output from the oscillator to be incident on the position of the reflecting surface calculated by the reflecting surface position calculation unit, and generates a position command for the scanning galvanometer based on the position. as well as The galvanometer control unit controls the scanning galvanometer based on the position command.

6. The laser processing machine according to claim 5, characterized in that, The reflector position calculation unit calculates the direction of reflection toward the target irradiation position, i.e., the target reflection direction, based on the target irradiation position, and calculates the position of the reflector based on the target reflection direction and the output direction of the laser output from the oscillator.

7. The laser processing machine according to claim 1, characterized in that, It also has an optical component disposed between the mirror and the optical path of the condenser lens, which corrects the laser light reflected by the mirror.

8. The laser processing machine according to claim 7, characterized in that, The optical component corrects the laser beam reflected by the galvanometer so that the beam diameter of the laser beam incident on the condenser lens is the same as the beam diameter of the laser beam output from the oscillator.

9. The laser processing machine according to claim 8, characterized in that, In addition to correcting the beam diameter of the laser incident on the condenser lens, the optical component also corrects the laser beam reflected by the galvanometer so that the shape of the laser beam incident on the condenser lens becomes circular.

10. The laser processing machine according to claim 1, characterized in that, It also includes a mounting platform with a planar placement surface on which the workpiece is placed. The scanning galvanometer is configured such that the plane is tilted relative to a direction perpendicular to the mounting surface.

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