JP2006122988A - Laser beam machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a laser beam machine which, even if each of the spectroscoped two laser beams is linearly polarized light, can form a machined hole of complete roundness on such a workpiece that a machined hole thereon tends to be elliptical with linear polarization. <P>SOLUTION: In the laser beam machine 100 that drills a hole at a prescribed position of a workpiece 13 by scanning a laser beam 2 emitted from a laser oscillator 1 with a galvano scanner 12 and by irradiating the workpiece 13 with the laser beam 2, there are provided a linearly polarization optical system 16 in which the laser beams emitted from the laser oscillator and made incident on the mirror 12a of the galvano scanner are transformed into linear polarized laser beams 7a, 8a having a polarizing azimuth angle of roughly 45° to the incident face of the mirror, and a galvano scanner 12 in which the one mirror 12a has a function of a 1/4 wavelength retardation plate and in which the incident linear polarized laser beams are transformed into circularly polarized laser beams 7b, 8b and emitted to the workpiece. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser processing machine that performs processing such as drilling on a workpiece such as a printed board.

  As a conventional laser processing machine that performs processing such as drilling on a workpiece such as a printed circuit board, one laser beam is split into two laser beams by a first polarizing beam splitter, and one laser beam passes through a mirror. The other laser beam is scanned in the YZ2 axis direction by the first galvano scanner, the two laser beams are guided to the second polarization beam splitter, and then scanned in the XY2 axis direction by the second galvano scanner, A laser processing machine for processing a workpiece on an XY stage, wherein the laser light transmitted through the first polarizing beam splitter is reflected by the second polarizing beam splitter, and is reflected by the first polarizing beam splitter. There is a laser processing machine in which the optical path is configured to transmit the second polarization beam splitter. This laser processing machine can perform processing at two locations simultaneously by scanning two laser beams separately (see, for example, Patent Document 1).

WO 03/085101 Pamphlet

  However, in the above-described conventional laser processing machine, the two laser beams irradiated to the workpiece are linearly polarized light having 90 ° polarization directions different from each other. Therefore, depending on the material of the workpiece, the linearly polarized light of the laser beam may be used. There was a problem that the processing hole became an ellipse depending on the component. In addition, there is a problem that the major axis direction of the elliptical hole varies depending on which laser beam is used for processing. As described above, the phenomenon that the machining hole becomes an ellipse is remarkable when the workpiece is a copper foil.

  The present invention has been made in view of the above, and is true for a workpiece in which the processing holes are likely to be elliptical in linearly polarized light even if each of the two split laser beams is linearly polarized light. An object of the present invention is to obtain a laser processing machine capable of forming a circular processing hole.

  In order to solve the above-described problems and achieve the object, the laser processing machine of the present invention scans the laser beam emitted from the laser oscillator with a galvano scanner and irradiates the workpiece, In a laser processing machine that performs drilling at a predetermined position, a linearly polarized laser having a polarization azimuth angle of approximately 45 ° with respect to the incident surface of the mirror is used to emit laser light emitted from the laser oscillator and incident on the mirror of the galvano scanner. A linearly polarizing optical system that converts light into light and a single mirror function as a quarter-wave retardation plate, and converts the incident linearly polarized laser light into circularly polarized laser light and irradiates the workpiece. And a galvano scanner.

  According to this invention, even if the laser light emitted from the laser oscillator is incident on the mirror of the galvano scanner in a linearly polarized state by the linear polarization optical system, this mirror has the function of a quarter wavelength phase difference plate. Therefore, the incident linearly polarized laser beam is converted into a circularly polarized laser beam and irradiated onto the workpiece.

  According to the present invention, the circularly polarized laser beam is used to process the workpiece whose machining hole is likely to be elliptical with the linearly polarized laser beam, so that a perfect circular hole can be formed. In addition, since the galvano scanner mirror has the function of a quarter-wave retardation plate, it is not necessary to insert a quarter-wave retardation plate in the optical path, and the number of optical elements increases in the optical path. The problem that it becomes easy to generate astigmatism at the time of image formation of the laser beam on the workpiece does not occur, and the deterioration of the laser beam quality can be prevented. Furthermore, by adopting a coating type quarter wavelength phase difference plate, it is possible to manufacture a laser processing machine at a lower cost compared to employing a transmission type quarter wavelength phase difference plate. Play.

  Embodiments of a laser beam machine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a schematic configuration of a first embodiment of a laser beam machine according to the present invention, and FIG. 2 is a schematic diagram of a spectrum of P wave 7 and S wave 8 by a first polarization beam splitter 6. 3 is a reflection schematic diagram of the P wave 7 by the second polarization beam splitter 9, FIG. 4 is a transmission schematic diagram of the S wave 8 by the second polarization beam splitter 9, and FIG. FIG. 6 is an enlarged view showing the optical path of the P wave 7 after being reflected by the second polarizing beam splitter 9, and FIG. 6 is an enlarged view showing the optical path of the S wave 8 after passing through the second polarizing beam splitter 9. is there.

  As shown in FIG. 1, the laser beam machine 100 according to the first embodiment is a multi-beam laser beam machine with one head, and the laser beam 2 linearly polarized (2a) in a direction inclined by 45 ° from the horizontal plane is converted into the Y axis. The laser oscillator 1 that emits in the (−) direction (see the XYZ coordinate axes in FIG. 1) and the laser beam 2 (2a) in the Y-axis (−) direction are reflected in the X-axis (−) direction, and the circularly polarized light 2 ( 2b), a retarder 3 for converting the laser light 2 (2b) and a mask 4 for narrowing, a plurality of mirrors 5a, 5b, 5c, 5d for reflecting the laser light to change the optical path, and a circularly polarized laser light The first polarization beam splitter 6 that splits 2 (2b) into two linearly polarized laser beams 7 (7a) and 8 (8a) and the linearly polarized laser beam 8 (8a) are scanned in the YZ2 axis direction to obtain a second First galvanoski incident on the polarizing beam splitter 9 A linear polarization laser beam 7 (7a), 8 (8a) that is incident on the second galvano scanner 12, and linearly polarized laser beams 7 (7a), 8 (8a). A second galvano scanner 12 that scans in the XY biaxial direction, converts to circularly polarized laser beams 7 (7b) and 8 (8b), and enters the fθ lens 10, and circularly polarized laser beams 7 (7b) and 8 An fθ lens 10 for condensing (8b) on the workpiece 13 and an XY stage 14 for placing and moving the workpiece 13 such as a printed board and positioning it on the XY plane are provided.

  The first polarizing beam splitter 6, the first galvano scanner 11, the mirrors 5c and 5d, the second polarizing beam splitter, and the like constitute a linearly polarizing optical system 16.

  With reference to FIG. 1, each component of the laser processing machine 100 of Embodiment 1 is demonstrated. The laser oscillator 1 emits laser light 2 linearly polarized (2a) in a direction inclined by 45 ° from a horizontal plane in the Y-axis (−) direction. The retarder 3 reflects the linearly polarized laser beam 2 (2a) traveling in the Y-axis (−) direction in the X-axis (−) direction, and the polarization direction of the linearly polarized laser beam 2 (2a) is the incident surface of the retarder 3 Therefore, the linearly polarized laser beam 2 (2a) is converted into the circularly polarized laser beam 2 (2b). The mask 4 shapes the circularly polarized laser beam 2 (2b) by narrowing down. The mirror 5a reflects the circularly polarized laser beam 2 (2b) traveling in the X-axis (−) direction in the Z-axis (−) direction. The mirror 5b reflects the circularly polarized laser beam 2 (2b) traveling in the Z-axis (−) direction in the X-axis (+) direction.

  Here, the structure and function of the first polarizing beam splitter 6 will be described with reference to FIG. FIG. 2 is a diagram showing the first polarization beam splitter 6, the center being a plan view, the left side is a front view on the incident side of the circularly polarized laser beam 2 (2 b), and the right side is a rear surface on the P wave emission side. FIG. 4 is a top view showing the S wave emission side on the upper side. The window surface 61 that is the incident surface of the circularly polarized laser beam 2 (2b) of the first polarizing beam splitter 6 is formed to be inclined 22.5 ° upward from the reference plane 64 in the figure, and the material thereof is a carbon dioxide laser. In this case, it is ZnSe or Ge. The mirror surface 62 of the first polarizing beam splitter 6 is formed with an inclination of 67.5 ° from the reference surface 64, and the S wave 8 (8a) reflected by the window surface 61 is incident on the incident circularly polarized laser beam 2 (2b). The direction is changed by 90 ° with respect to the direction.

  As shown in FIG. 1, the first polarizing beam splitter 6 having the above-described structure and function has a horizontal plane so that the emission direction of the S wave 8 (8a) is inclined 45 ° counterclockwise from the horizontal plane. It is installed at 45 ° counterclockwise. The circularly polarized laser beam 2 (2b) reflected in the X-axis (+) direction by the mirror 5b is incident on the window surface 61 of the first polarization beam splitter 6, and the polarization direction is perpendicular to the window surface 61. The P wave component 7 (7a) is transmitted through the window surface 61 and emitted from the back surface 63 in the X-axis (+) direction. Since the first polarization beam splitter 6 is inclined 45 ° counterclockwise with respect to the horizontal plane, the polarization direction of the P wave component 7 (7a) is also inclined 45 ° counterclockwise with respect to the horizontal plane.

  The mirror 5c reflects the P-wave component linearly polarized laser light 7 (7a) traveling in the X-axis (+) direction in a direction inclined 45 ° clockwise from the horizontal plane in the YZ plane. The mirror 5 d reflects the linearly polarized laser beam 7 (7 a) reflected by the mirror 5 c in a direction inclined 45 ° counterclockwise from the horizontal plane in the YZ plane and enters the mirror surface 92 of the second polarizing beam splitter 9. Let

  On the other hand, the S wave component 8 (8a) whose polarization direction is horizontal with respect to the window surface 61 of the first polarizing beam splitter 6 is reflected by the window surface 61 and the mirror surface 62 and is reflected from the horizontal plane in the YZ plane. The light is emitted in a direction inclined 45 ° clockwise. The pre-stage mirror 11a of the first galvano scanner 11 is installed with its rotation axis directed in the X-axis direction, and outputs the S-wave component linearly polarized laser beam 8 (8a) emitted from the first polarization beam splitter 6 to YZ. The light is reflected in a direction inclined 45 ° clockwise from the horizontal plane in the plane, and is scanned at a predetermined angle in the YZ2 axis direction.

  The rear stage mirror 11b of the first galvano scanner 11 is installed with its rotation axis tilted 45 ° counterclockwise from the horizontal plane in the YZ plane, and a straight line of the S wave component emitted from the front stage mirror 11a. The polarized laser beam 8 (8a) is reflected in the X-axis (+) direction and scanned by a predetermined angle in the YZ2 axis direction orthogonal to the scanning direction of the front mirror 11a. Make it incident. The linearly polarized laser beam 8 (8a) is adjusted in the incident position and the incident angle on the back surface 93 of the second polarizing beam splitter 9 by adjusting the swing angle of the first galvano scanner 11. Since the circularly polarized laser beam 2 (2b) has polarization components in all directions uniformly, the linearly polarized laser beam 7 (7a) and the linearly polarized laser beam 8 (8a) have the same energy. Is spectroscopic.

  Here, the installation direction and function of the second polarization beam splitter 9 will be described with reference to FIGS. FIG. 3 is a diagram showing the second polarization beam splitter 9, in which the center is a plan view, the lower side is a bottom view on the incident side of the linearly polarized laser beam 7 (7 a), and the right side is the linearly polarized laser beam 7 (7 a). It is a rear view which is the output side. FIG. 4 is also a diagram showing the second polarization beam splitter 9, in which the center is a plan view, the left side is a front view on the incident side of the linearly polarized laser beam 8 (8 a), and the right side is the linearly polarized laser beam 8 (8 a It is a rear view which is an output side. The second polarizing beam splitter 9 has the same structure and function as the first polarizing beam splitter 6. The second polarizing beam splitter 9 rotates the first polarizing beam splitter 6 around the Z axis by 180 ° and rotates around the X axis. It is installed 45 degrees counterclockwise from the horizontal direction.

  As shown in FIGS. 3 and 5, the linearly polarized laser beam 7 (7 a) incident on the mirror surface 92 of the second polarizing beam splitter 9 is an S wave component with respect to the second polarizing beam splitter 9. Then, the light is reflected by the mirror surface 92 and the window surface 91, is emitted in the X-axis (+) direction, and enters the front stage mirror 12a of the second galvano scanner 12. At this time, the polarization direction of the linearly polarized laser beam 7 (7a) is inclined 45 ° clockwise with respect to the horizontal plane.

  On the other hand, as shown in FIGS. 4 and 6, the linearly polarized laser light 8 (8 a) incident on the back surface 93 of the second polarizing beam splitter 9 becomes a P wave component with respect to the second polarizing beam splitter 9. Then, the light passes through the back surface 93 and the window surface 91, is emitted in the X-axis (+) direction, and enters the front stage mirror 12 a of the second galvano scanner 12. At this time, the polarization direction of the linearly polarized laser beam 8 (8a) is inclined 45 ° counterclockwise with respect to the horizontal plane.

  The front stage mirror 12a of the second galvano scanner 12 is installed with its rotation axis directed in the Z-axis direction, and receives the linearly polarized laser beams 7 (7a) and 8 (8a) emitted from the second polarization beam splitter 9. Reflecting in the Y-axis (-) direction and scanning at a predetermined angle in the X-axis direction.

  The front stage mirror 12a of the second galvano scanner 12 has the same function as a quarter-wave retardation plate that converts linearly polarized light into circularly polarized light by coating, like the retarder 3 described above. Since the linearly polarized laser beams 7 (7a) and 8 (8a) have a polarization azimuth angle of 45 ° with respect to the incident surface of the mirror 12a, they are converted into circularly polarized laser beams 7 (7b) and 8 (8b) after reflection. Has been.

  The rear-stage mirror 12b of the second galvano scanner 12 is installed with its rotational axis directed in the X-axis direction, emitted from the front-stage mirror 12a, and scanned at a predetermined angle in the X-axis direction, and is a circularly polarized laser beam 7 (7b). , 8 (8b) are reflected in the Z-axis (−) direction and scanned in the Y-axis direction by a predetermined angle. The circularly polarized laser beams 7 (7b) and 8 (8b) are scanned at a predetermined angle in the XY biaxial direction by the front-stage mirror 12a and the rear-stage mirror 12b.

  The fθ lens 10 condenses the circularly polarized laser beams 7 (7b) and 8 (8b) emitted from the rear stage mirror 12b of the second galvano scanner 12 on the workpiece 13 on the XY stage 14, and the XY stage. 14 moves and positions the workpiece 13 on the XY plane, and simultaneously drills holes in two predetermined positions of the workpiece 13.

  At this time, by scanning the first galvano scanner 11, the circularly polarized laser beam 8 (8b) can be irradiated on the workpiece 13 at the same position as the circularly polarized laser beam 7 (7b). . Further, the circularly polarized laser beam 8 (8b) is circularly polarized by scanning, for example, the first galvano scanner 11 with respect to the circularly polarized laser beam 7 (7b) within a preset range. Taking into account the characteristics of the window surface 91 of the second beam splitter 9 with the laser beam 7 (7b) as the center, scanning is performed within the range of 4 mm square, and for example, the first swings within a workable range such as 50 mm square. Two different points on the workpiece 13 can be irradiated with circularly polarized laser beams 7 (7b) and 8 (8b) via the two galvano scanners 12. Further, by moving the workpiece 13 on the XY stage 14, a wide range of machining of the workpiece 13 can be performed.

  When the front stage mirror 12a of the second galvano scanner 12 is swung for scanning the linearly polarized laser beams 7 (7a) and 8 (8a), the linearly polarized laser beams 7 (7a) and 8 for the front stage mirror 12a are swung. The polarization azimuth angle of (8a) changes. Conversion of linearly polarized laser light into circularly polarized laser light by the quarter wavelength phase difference plate has a polarization azimuth angle dependency, and when the 45 ° polarization azimuth angle changes, the major axis and minor axis of the circularly polarized laser beam spot change. The ratio of circular polarization changes. The swing angle of the front-stage mirror 12a is about ± 8 °. In this case, the polarization azimuth of the linearly polarized laser beams 7 (7a) and 8 (8a) with respect to the quarter-wave retardation plate is also changed by about ± 8 °. Will occur. However, if the polarization azimuth angle changes to such a degree, the degree of circular polarization of the linearly polarized laser beams 7 (7a) and 8 (8a) reflected by the quarter-wave retardation plate is about 30%. If the degree of polarization is about 30%, holes with good roundness can be processed.

  According to the laser beam machine 100 of the first embodiment described above, even if the two split laser beams 7 and 8 are linearly polarized light 7a and 8a, respectively, the first stage mirror 12a of the second galvano scanner 12 has 1 The circularly polarized light 7b, 8b can be converted into a circularly polarized light 7b, 8b by giving the function of a / 4 wavelength phase difference plate, and the work piece whose hole is easy to be processed into an ellipse in the linearly polarized light 7a, 8a Can be machined.

  In addition, since the first-stage mirror 12a of the second galvano scanner has a function of a quarter-wave retardation plate, it is not necessary to separately insert a quarter-wave retardation plate in the optical path of the laser beam. The increase in the number of optical elements does not cause a problem that astigmatism easily occurs during image formation on the workpiece, and it is possible to prevent the quality of the laser light from being deteriorated. Furthermore, by adopting a coating type quarter wavelength phase difference plate, it can be manufactured at a lower cost than when a transmission type quarter wavelength phase difference plate is adopted.

Embodiment 2. FIG.
FIG. 7 is a diagram showing a schematic configuration of the laser beam machine according to the second embodiment of the present invention. In FIG. 7, the same components as those shown in FIGS. The laser beam machine 200 according to Embodiment 2 is a two-head single beam laser beam machine. The laser beam machine 200 splits one circularly polarized laser beam 2 (2a) into two linearly polarized laser beams 7 (7a) and 8 (8a) by the polarization beam splitter 6, and two linearly polarized laser beams 7 (7a). ), 8 (8a) are separately scanned and incident on separate fθ lenses 10b and 10a, and the two workpieces 13b and 13a on the XY stage 14 are simultaneously processed. A linearly polarizing optical system 17 is constituted by the polarizing beam splitter 6 and mirrors 5b, 5c, 5d described later.

  With reference to FIG. 7, the component of the laser beam machine 200 of Embodiment 2 is demonstrated. The laser oscillator 21 emits the circularly polarized (2b) laser beam 2 in the X-axis (+) direction (see the XYZ coordinate axes in FIG. 7). As shown in FIG. 7, the polarization beam splitter 6 having the same structure and function as the first polarization beam splitter 6 of the laser beam machine 100 according to the first embodiment has an emission direction of the S wave 8 (8a) from the horizontal plane. It is installed at 45 ° clockwise from the horizontal plane so that it is inclined 45 ° around. Another optical device such as a mask may be inserted in the optical path between the laser oscillator 21 and the polarization beam splitter 6.

  The circularly polarized laser beam 2 (2 b) emitted from the laser oscillator 21 is incident on the window surface 61 (see FIG. 2) of the polarization beam splitter 6, and the P wave component 7 whose polarization direction is perpendicular to the window surface 61. (7a) passes through the window surface 61 and exits from the back surface 63 in the X-axis (+) direction. Since the polarization beam splitter 6 is inclined 45 ° clockwise relative to the horizontal plane, the polarization direction of the P-wave component 7 (7a) is also inclined 45 ° clockwise relative to the horizontal plane.

  The mirror 5c reflects the P-wave component linearly polarized laser light 7 (7a) traveling in the X-axis (+) direction in a direction inclined 45 ° clockwise from the horizontal plane in the YZ plane. The mirror 5 d reflects the linearly polarized laser beam 7 (7 a) reflected by the mirror 5 c in the X-axis (+) direction and makes it incident on the front stage mirror 12 a of the second galvano scanner 12. At this time, the polarization direction of the linearly polarized laser beam 7 (7a) is inclined 45 ° clockwise with respect to the horizontal plane.

  The front stage mirror 12a of the second galvano scanner 12 is installed with its rotation axis directed in the Z-axis direction, and reflects the linearly polarized laser light 7 (7a) emitted from the mirror 5d in the Y-axis (−) direction, In addition, scanning is performed at a predetermined angle in the X-axis direction.

  The front stage mirror 12a of the second galvano scanner 12 has the same function as a quarter-wave retardation plate that converts linearly polarized light into circularly polarized light by coating. Since the linearly polarized laser beam 7 (7a) has a polarization azimuth angle of 45 ° with respect to the incident surface of the mirror 12a, it is converted into a circularly polarized laser beam 7 (7b) after reflection.

  The rear-stage mirror 12b of the second galvano scanner 12 is installed with its rotational axis directed in the X-axis direction, emitted from the front-stage mirror 12a, and scanned at a predetermined angle in the X-axis direction, and is a circularly polarized laser beam 7 (7b). Are reflected in the Z-axis (−) direction and scanned in the Y-axis direction by a predetermined angle. The circularly polarized laser beam 7 (7b) is scanned at a predetermined angle in the XY2 axis direction by the front-stage mirror 12a and the rear-stage mirror 12b.

  The fθ lens 10b condenses the circularly polarized laser beam 7 (7b) emitted from the rear stage mirror 12b of the second galvano scanner 12 on the workpiece 13b on the XY stage 14, and the XY stage 14 The object 13b is moved and positioned on the XY plane, and predetermined hole machining is performed at a predetermined position of the workpiece 13b.

  On the other hand, the S wave component 8 (8a) whose polarization direction is horizontal with respect to the window surface 61 of the polarizing beam splitter 6 is reflected by the window surface 61 and the mirror surface 62, and is 45 ° clockwise from the horizontal plane in the YZ plane. The light is emitted in an inclined direction. The mirror 5 b reflects the S-wave component linearly polarized laser light 8 (8 a) emitted from the polarization beam splitter 6 in the X-axis (+) direction and makes it incident on the front-stage mirror 11 a of the first galvano scanner 11. At this time, the polarization direction of the linearly polarized laser beam 8 (8a) is inclined 45 ° counterclockwise with respect to the horizontal plane. Since the circularly polarized laser beam 2 (2b) has polarization components in all directions uniformly, the linearly polarized laser beam 7 (7a) and the linearly polarized laser beam 8 (8a) have the same energy. Is spectroscopic.

  The pre-stage mirror 11a of the first galvano scanner 11 is installed with its rotational axis directed in the Z-axis direction, and reflects the linearly polarized laser light 8 (8a) emitted from the mirror 5b in the Y-axis (−) direction. Further, scanning is performed at a predetermined angle in the X-axis direction.

  The front stage mirror 11a of the first galvano scanner 11 has the same function as a quarter-wave retardation plate that converts linearly polarized light into circularly polarized light by coating. Since the linearly polarized laser beam 8 (8a) has a polarization azimuth angle of 45 ° with respect to the incident surface of the mirror 11a, it is converted into a circularly polarized laser beam 8 (8b) after reflection.

  The rear-stage mirror 11b of the first galvano scanner 11 is installed with its rotation axis directed in the X-axis direction, emitted from the front-stage mirror 11a, and scanned at a predetermined angle in the X-axis direction, and is a circularly polarized laser beam 8 (8b). Are reflected in the Z-axis (−) direction and scanned in the Y-axis direction by a predetermined angle. The circularly polarized laser beam 8 (8b) is scanned at a predetermined angle in the XY2 axis direction by the front-stage mirror 11a and the rear-stage mirror 11b.

  The fθ lens 10a condenses the circularly polarized laser light 8 (8b) emitted from the rear stage mirror 11b of the first galvano scanner 11 on the workpiece 13a on the XY stage 14, and the XY stage 14 The object 13a is moved and positioned on the XY plane, and predetermined hole processing is performed at a predetermined position of the workpiece 13a.

  As described above, the two-head single beam laser processing machine 200 according to the second embodiment applies the circularly polarized laser beams 8 (8b) and 7 (7b) to any two different points on the workpieces 13a and 13b, respectively. It is possible to irradiate.

  According to the laser beam machine 200 of the second embodiment described above, the first and second galvano scanners 11 and 12 can be used even if the two laser beams 8 and 7 thus separated are linearly polarized light 8a and 7a, respectively. The first stage mirrors 11a and 12a can be converted into circularly polarized light 8b and 7b by giving the function of a quarter-wave retardation plate. In the linearly polarized light 8a and 7a, the two workpieces whose holes were easily processed into an ellipse A hole close to a perfect circle can be simultaneously processed for the objects 13a and 13b.

  In addition, since the first-stage mirrors 11a and 12a of the first and second galvano scanners have the function of the quarter-wave retardation plate, it is necessary to separately insert the quarter-wave retardation plate into the optical path of the laser beam. As a result, there is no problem that astigmatism is easily generated when an image is formed on the workpiece due to an increase in the number of optical elements in the optical path, and it is possible to prevent deterioration of the quality of the laser beam. Furthermore, by adopting a coating type quarter wavelength phase difference plate, it can be manufactured at a lower cost than when a transmission type quarter wavelength phase difference plate is adopted.

  In the laser processing machines 100 and 200 according to the first and second embodiments, the former-stage mirrors 12a, 11a, and 12a of the galvano scanners 12, 11, and 12 are provided with the function of a quarter-wave retardation plate. You may make it give the function of a quarter wavelength phase difference plate to 12b, 11b, 12b. In this way, the linearly polarized light 8a and 7a can be converted into the circularly polarized light 8b and 7b, and the same effects as those of the laser processing machines 100 and 200 of the first and second embodiments can be obtained. However, since the linearly polarized laser beams 8 (8a) and 7 (7a) scanned by the front-stage mirrors 12a, 11a, and 12a are incident on the rear-stage mirrors 12b, 11b, and 12b, it is necessary to increase the mirror area. Since the coating area for providing the function of the quarter-wave retardation plate is increased, the cost is increased, and the flatness of the mirror is liable to occur. You should do it.

  As described above, the laser processing machine according to the present invention is useful for drilling a printed circuit board or the like, and is particularly suitable for precise drilling.

It is a figure which shows schematic structure of Embodiment 1 of the laser beam machine concerning this invention. It is a spectrum schematic diagram of P wave and S wave by the 1st polarization beam splitter. It is a reflection schematic diagram of the P wave by the 2nd polarization beam splitter. It is a transmission schematic diagram of S wave by the 2nd polarization beam splitter. It is an enlarged view which shows the optical path of P wave after permeate | transmitting a 1st polarizing beam splitter. It is an enlarged view which shows the optical path of the S wave after reflection with the 1st polarizing beam splitter. It is a figure which shows schematic structure of Embodiment 2 of the laser beam machine concerning this invention.

Explanation of symbols

1, 21 Laser oscillator 2, 7, 8 Laser light 2a, 7a, 8a Linearly polarized light 2b, 7b, 8b Circularly polarized light 3 Retarder 4 Mask 5a, 5b, 5c, 5d Mirror 6, 9 Polarizing beam splitter 10, 10a, 10b fθ Lens 11, 12 Galvano scanner 11a, 12a Front stage mirror 11b, 12b Rear stage mirror 13, 13a, 13b Workpiece 14 XY stage

Claims (4)

In a laser processing machine that scans laser light emitted from a laser oscillator with a galvano scanner and irradiates the workpiece, and performs drilling at a predetermined position of the workpiece,
A linearly polarized optical system that converts laser light emitted from the laser oscillator and incident on the mirror of the galvano scanner into linearly polarized laser light having a polarization azimuth angle of approximately 45 ° with respect to the incident surface of the mirror;
A mirror having a function of a quarter wavelength phase difference plate, converting the incident linearly polarized laser beam into a circularly polarized laser beam and irradiating the workpiece;
A laser processing machine comprising:   The laser processing machine according to claim 1, wherein the mirror having the function of the ¼ wavelength phase difference plate is a front stage mirror of the galvano scanner.   The linearly polarizing optical system splits laser light emitted from one laser oscillator into two linearly polarized laser beams by a first polarizing beam splitter, and the two linearly polarized laser lights by a second polarizing beam splitter. The laser beam machine according to claim 1 or 2, wherein the laser beam machine is a linearly polarized optical system that collects and enters the mirror of the galvano scanner. The laser processing machine includes two galvano scanners corresponding to two workpieces,
The linearly polarized optical system splits laser light emitted from one laser oscillator into two linearly polarized laser beams by a polarization beam splitter, and distributes each of the split linearly polarized laser beams to each of the two galvano scanners. The laser beam machine according to claim 1, wherein the laser beam machine is incident and simultaneously drills two workpieces.

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