TW202203528A - Beam-shaping optical device and true roundness adjustment method to make the beam profile close to a true circle - Google Patents

Abstract

The subject of the invention is to provide a beam-shaping optical device that can make the beam profile close to a true circle. The solution is to arrange a correction optical part including a cylindrical mirror or a cylindrical lens on the path of the laser beam. A condensing optical part is composed of a convex lens or a concave mirror is arranged on the path of the laser beam passing through the correction optical part. The support mechanism movably supports the correction optical part in the direction of changing the optical path length of the laser beam between the correction optical part and the condensing optical part.

Description

Beam shaping optical device and roundness adjustment method

The invention relates to a beam shaping optical device and a roundness adjustment method. This application claims priority based on Japanese Patent Application No. 2020-117103 filed on July 7, 2020. The entire contents of the Japanese application are incorporated in this specification by reference.

A conventional laser processing apparatus for drilling a workpiece such as a substrate will be described. The laser beam output from the laser oscillator is guided to a concave mirror, and condensed to a predetermined size at the transfer source position of the beam expander. The beam expander transfers the beam profile from the transfer source location to the orifice location. A laser beam having a substantially circular profile of the beam profile through the aperture is incident on the surface of the object to be processed through a Galvano scanner and an fθ lens.

In order to form a circular hole in an object to be processed, it is desired to improve the roundness of the beam profile on the surface of the object to be processed. Roundness refers to the amount of deviation from the geometrically correct circle of a circular shape. For example, when a circular shape is sandwiched between two concentric geometric circles, it can be represented by the difference between the radii of the two circles when the distance between the two concentric circles is the smallest. The smaller the difference in radii, the closer the circular shape is to a true circle. The following Patent Document 1 discloses a laser oscillator that realizes a true beam mode by arranging mirrors having shapes with different radii of curvature with respect to two orthogonal directions in an optical resonator of a laser beam. Circularity improvement. [Prior Art Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2017-34055

In the conventional apparatus, the outer shape of the beam cross-section is made circular by the aperture, but the shape of the beam cross-section on the surface of the object may be deformed from the circular shape. This is because the beam profile or the divergence angle of the beam in the position where the aperture is arranged is different in the longitudinal direction and the transverse direction.

[Problems to be Solved by Invention]

An object of the present invention is to provide a beam shaping optical device and a roundness adjustment method capable of making the beam profile close to a true circle. [Technical means to solve problems]

According to an aspect of the present invention, a beam shaping optical device is provided, which has: Correction optical parts, which are arranged on the path of the laser beam and include cylindrical mirrors or cylindrical lenses; The condensing optical component is disposed on the path of the laser beam passing through the correction optical component, and is composed of a convex lens or a concave mirror; and The supporting mechanism supports the correction optical part movably in the direction of changing the optical path length of the laser beam between the correction optical part and the condensing optical part.

According to another aspect of the present invention, there is provided a roundness adjustment method, which comprises the following steps: The laser beam is condensed to the reference position through correction optical parts including cylindrical mirrors or cylindrical lenses and condensing optical parts composed of convex lenses or concave mirrors, The optical path length of the laser beam between the correction optical part and the condensing optical part is changed, so that the beam profile of the laser beam at the reference position is close to a true circle. [Effect of invention]

When correcting optical components are arranged, one of the divergence angles of the beams in the two directions orthogonal to the optical axis of the laser beam is fixed, and the other is changed. By changing the optical path length between the correction optical part and the condensing optical part, the variation of the divergence angle can be adjusted. Thereby, the beam profile can be made close to a true circle.

Referring to FIG. 1 to FIG. 5C , a beam shaping optical device according to an embodiment will be described. FIG. 1 is a schematic diagram of a laser processing apparatus equipped with a beam shaping optical device 50 of this embodiment. The laser processing apparatus includes a laser oscillator 12 , a processing apparatus 80 and a control apparatus 70 .

The laser oscillator 12 is supported on the stage 11 , and the stage 11 is fixed on the common base 100 . The processing device 80 includes a beam shaping optical device 50 , a beam scanner 81 , an fθ lens 82 , and a stage 85 . The object to be processed 90 is held on the table 85 . The beam shaping optical device 50 , the beam scanner 81 , the fθ lens 82 and the stage 85 are supported on the common base 100 . The common base 100 is, for example, a floor.

The laser oscillator 12 outputs a pulsed laser beam. As the laser oscillator 12, for example, a carbon dioxide laser oscillator is used. The pulsed laser beam output from the laser oscillator 12 has a beam profile shaped by the beam shaping optical device 50 , and is incident on the object 90 via the beam scanner 81 and the fθ lens 82 . The beam scanner 81 scans the laser beam in two directions. The table 85 moves the object 90 in two directions parallel to the surface thereof. The control device 70 controls the beam shaping optical device 50 so that the shape of the beam cross section is close to a true circle.

The beam scanner 81 scans the laser beam in two directions, and performs drilling processing by making the pulsed laser beam incident on a desired position of the object 90 to be processed. When the scannable range of the pulsed laser beam does not cover the entire area of the surface of the object 90 , by moving the object 90 by the stage 85 , it is possible to scan the substantially entire area of the surface of the object 90 . processing.

FIG. 2 is a cross-sectional view including the optical axis of the laser oscillator 12 . The laser oscillator 12 includes a chamber 15 for accommodating the laser dielectric gas and the optical resonator 20 and the like. The laser medium gas is contained in the chamber 15 . The inner space of the chamber 15 is divided into an optical chamber 16 located relatively on the upper side and a blower chamber 17 relatively located on the lower side. The optical chamber 16 and the blower chamber 17 are partitioned by upper and lower partition plates 18 . In addition, the upper and lower partition plates 18 are provided with openings for allowing the laser medium gas to flow between the optical chamber 16 and the blower chamber 17 . The bottom plate 19 of the optical chamber 16 protrudes from the side wall of the blower chamber 17 in the direction of the optical axis 20A of the optical resonator 20 .

The bottom plate 19 of the chamber 15 is supported on the stage 11 ( FIG. 1 ) at four support locations 45 . The four support parts 45 are arranged at positions corresponding to the four vertices of the rectangle in plan view.

A pair of discharge electrodes 21 and a pair of resonator mirrors 25 are arranged in the optical chamber 16 . A pair of discharge electrodes 21 are respectively fixed to the electrode case 22 . The pair of electrode boxes 22 are supported on the bottom plate 19 via a plurality of electrode support members 23 . The pair of discharge electrodes 21 are arranged at intervals in the up-down direction to define the discharge region 24 therebetween. The discharge electrode 21 generates a discharge in the discharge region 24, thereby exciting the laser dielectric gas. The pair of resonator mirrors 25 constitute the optical resonator 20 having the optical axis 20A passing through the discharge region 24 . As will be described later with reference to FIG. 3 , the laser dielectric gas flows through the discharge region 24 in a direction perpendicular to the page of FIG. 2 .

A pair of resonator mirrors 25 are fixed on a common resonator base 26 disposed in the optical chamber 16 . The resonator base 26 is a plate-like member long in the direction of the optical axis 20A, and is supported on the bottom plate 19 via a plurality of optical resonator support members 27 .

A light-transmitting window 28 for transmitting the laser beam is attached to the intersection of the extension line extending the optical axis 20A of the optical resonator 20 in one direction (leftward in FIG. 1 ) and the wall surface of the optical chamber 16 . The laser beam excited in the optical resonator 20 is emitted to the outside through the light-transmitting window 28 .

A blower 29 is arranged in the blower chamber 17 . The blower 29 circulates the laser medium gas between the optical chamber 16 and the blower chamber 17 .

FIG. 3 is a cross-sectional view perpendicular to the optical axis 20A ( FIG. 2 ) of the laser oscillator 12 of the embodiment. As described with reference to FIG. 2 , the inner space of the chamber 15 is divided into an upper optical chamber 16 and a lower blower chamber 17 by the upper and lower partition plates 18 . A pair of discharge electrodes 21 and a resonator base 26 are arranged in the optical chamber 16 . A pair of discharge electrodes 21 are respectively fixed to the electrode case 22 . The electrode cartridge 22 is supported on the bottom plate 19 ( FIG. 2 ) of the chamber 15 by a plurality of electrode support members 23 . A discharge region 24 is defined between the pair of discharge electrodes 21 . The resonator base 26 is supported on the bottom plate 19 ( FIG. 2 ) of the chamber 15 by a plurality of optical resonator support members 27 . The electrode supporting member 23 and the optical resonator supporting member 27 are arranged at positions deviated from the cross-section shown in FIG. 3 , and therefore, the electrode supporting member 23 and the optical resonator supporting member 27 are indicated by dotted lines in FIG. 3 .

A partition plate 40 is arranged in the optical chamber 16 . The partition plate 40 defines a first gas flow path 41 from the opening 18A provided in the upper and lower partition plates 18 to the discharge region 24 and a second gas flow path 41 from the discharge region 24 to the other opening 18B provided in the upper and lower partition plate 18 . 2 gas flow path 42. The laser dielectric gas flows through the discharge region 24 in a direction orthogonal to the optical axis 20A (FIG. 2). The discharge direction is orthogonal to both the direction in which the laser medium gas flows and the optical axis 20A. A circulation path through which the laser medium gas circulates is formed by the blower chamber 17 , the first gas flow path 41 , the discharge region 24 , and the second gas flow path 42 . The blower 29 generates the flow of the laser medium gas shown by the arrow to circulate the laser medium gas in the circulation path.

The heat exchanger 43 is accommodated in the circulation path in the blower chamber 17 . The laser medium gas heated in the discharge region 24 is cooled by passing through the heat exchanger 43 , and the cooled laser medium gas is supplied to the discharge region 24 again.

Next, referring to FIG. 4 , the beam shaping optical device 50 of this embodiment will be described. FIG. 4 is a schematic diagram of a beam shaping optical device 50 of an embodiment. The beam shaping optical device 50 includes a correction optical part 51 , a condensing optical part 55 , a plane mirror 56 , a beam expander 60 , an aperture 61 , a plane mirror 62 , a support mechanism 65 and a detector 66 . The correction optical component 51 includes a cylindrical concave mirror 52 and a flat mirror 53 . The condensing optical component 55 is a concave mirror having a spherical or parabolic reflecting surface.

The laser beam output from the laser oscillator 12 is reflected by the cylindrical concave mirror 52 and further reflected by the flat mirror 53 to be incident on the condensing optical component 55 . The laser beam reflected by the condensing optical part 55 is reflected by the plane mirror 56 and incident on the beam expander 60 . The beam expander 60 transfers the beam profile of the reference position 63 between the plane mirror 56 and the beam expander 60 to the position of the aperture 61 by enlarging or reducing the beam diameter. The reference position 63 is sometimes referred to as a transfer source position. Regarding the beam expander 60, the reference position 63 and the position of the aperture 61 are in a conjugate relationship.

The aperture 61 shields the peripheral portion of the laser beam, and shapes the beam profile into a circular shape. The laser beam passing through the aperture 61 is reflected by the plane mirror 62 to be incident on the beam scanner 81 . The beam scanner 81 uses, for example, a galvano scanner. The beam scanner 81 scans the laser beam in two directions. The fθ lens 82 focuses the laser beam scanned by the beam scanner 81 on the surface of the object 90 to be processed. For example, the fθ lens 82 images the aperture 61 on the surface of the object 90 .

The support mechanism 65 movably supports the correction optical part 51 along the optical axis of the laser beam between the correction optical part 51 and the condensing optical part 55 . The correction optical part 51 moves in translation as shown by the double arrow in FIG. 4 . The corrected optical part 51 after the movement is shown with a broken line. The optical axis of the laser beam incident on the correction optical part 51 is parallel to the optical axis of the laser beam from the correction optical part 51 toward the condensing optical part 55 . The support mechanism 65 moves the correction optical component 51 while maintaining the relative positional relationship between the cylindrical concave mirror 52 and the plane mirror 53 . Therefore, even if the correction optical component 51 is moved, the optical path length of the laser beam from the laser oscillator 12 to the condensing optical component 55 does not change.

The detector 66 is movable between a reference position 63 on the path of the laser beam and a position offset from the path of the laser beam, as indicated by the double arrow. In FIG. 4, the detector 66 at the reference position 63 on the path of the laser beam is shown with a broken line, and the detector 66 at a position deviated from the path of the laser beam is shown with a solid line. The detector 66 detects the shape of the beam profile of the incident laser beam. As the detector 66, for example, a beam profiler can be used.

The detection result based on the detector 66 is input to the control device 70 . The control device 70 controls the support mechanism 65 according to the detection result of the detector 66 to move the correction optical component 51 . The control of the support mechanism 65 will be described in detail later.

Next, referring to FIGS. 5A to 5C , the divergence and convergence of the laser beam and the shape of the beam cross section in the beam shaping optical device 50 will be described.

In FIG. 5 , FIGS. 5A to 5C are schematic diagrams showing the divergence and convergence of the laser beam when the laser beam is assumed to travel straight without considering the bending of the path caused by the reflection of the laser beam. The xyz orthogonal coordinate system is defined, and the direction parallel to the generatrix of the cylindrical surface of the cylindrical concave mirror 52 ( FIG. 4 ) is the x direction, the plane perpendicular to the generatrix is the y direction, and the traveling direction of the laser beam is for the z direction. For example, the x direction corresponds to the direction in which the pair of discharge electrodes 21 (FIG. 2) are separated (discharge direction), and the y direction corresponds to the direction in which the laser dielectric gas flows within the discharge region 24 (FIG. 3).

5A and 5B show the divergence and convergence of the laser beam on the yz plane. In FIGS. 5A and 5B , the positions of the cylindrical concave mirrors 52 are different. In FIG. 5B, the same state as that shown in FIG. 5A is shown by a broken line. FIG. 5C shows the divergence and convergence of the laser beam on the zx plane. In FIGS. 5A to 5C , the optical axis 30 of the laser beam 31 output from the laser oscillator 12 is indicated by a two-dot chain line. Here, the "optical axis of the laser beam" refers to a straight line connecting the centers of the beam cross sections, and corresponds to a straight line extending the optical axis 20A of the optical resonator 20 in the laser oscillator 12 .

The laser beam 31 output from the laser oscillator 12 is guided to the reference position 63 via the cylindrical concave mirror 52 and the condensing optical component 55 . In this embodiment, at the exit of the laser oscillator 12 , the beam profile 32 of the laser beam 31 is an ellipse that is long in the x-direction. Further, the divergence angle θy of the laser beam 31 in the yz plane ( FIGS. 5A and 5B ) is larger than the divergence angle θx of the laser beam 31 in the zx plane ( FIG. 5C ).

As shown in FIGS. 5A and 5B , the cylindrical concave mirror 52 converges the laser beam 31 in the yz plane. In the zx plane, the cylindrical concave mirror 52 functions as a flat mirror and does not affect the convergence and divergence of the laser beam 31 .

The dotted line shown in FIG. 5A shows the divergence and convergence of the laser beam 31 when a plane mirror is arranged instead of the cylindrical concave mirror 52 . The divergence angle θy of the laser beam 31 in the yz plane is larger than the divergence angle θx of the laser beam 31 in the zx plane, so the beam profile 33 at the reference position 63 is shown by the dotted line in FIG. 5A , which is long in the y direction. oval.

If the cylindrical concave mirror 52 is arranged, the laser beam 31 converges in the yz plane, and the divergence and convergence of the laser beam 31 in the zx plane are not affected. Therefore, the size of the beam profile 33 at the reference position 63 is reduced in the y direction. In the state shown in FIG. 5A , the amount of contraction of the beam cross section 33 in the y direction becomes too large, and the beam cross section 33 becomes an ellipse that is long in the x direction as shown by the solid line.

As shown in FIG. 5B , when the cylindrical concave mirror 52 is moved toward the condensing optical component 55 , the convergence force of the laser beam 31 in the yz plane is weakened. In the zx plane, even if the cylindrical concave mirror 52 is moved, the divergence and convergence of the laser beam 31 are not affected. As a result, the beam profile 33 at the reference position 63 extends in the y direction from the beam profile 33 indicated by the solid line in FIG. 5A . As shown in FIGS. 5B and 5C , the beam profile 33 changes from the shape shown by the dotted line to the shape shown by the solid line, which is close to a true circle.

Next, the function of the control device 70 ( FIG. 4 ) will be described. The control device 70 acquires the detection result from the detector 66 and detects the shape of the beam cross section. Then, the support mechanism 65 is controlled to move the correction optical component 51 in a direction in which the shape of the beam cross-section approaches a true circle. When the difference between the shape of the beam profile at the current time and the true circle is within the allowable range, the control device 70 stops the correction optical component 51 .

Next, the excellent effects of the present embodiment will be described. According to the evaluation experiments of the inventors of the present application, it is clearly known that if the beam profile at the reference position 63 ( FIG. 4 ) as the transfer source of the beam expander 60 deviates from a true circle, even if the aperture 61 is used to shape the beam profile to be true circle, the shape of the hole being machined also deviates from a true circle. This is because even if only the profile of the beam profile is shaped into a true circle at the position of the aperture 61, the beam profile within the beam profile or the divergence angle of the laser beam is different in the longitudinal and transverse directions orthogonal to the optical axis. It can be seen that if the beam profile at the reference position 63 is made close to a true circle, the hole to be machined will be close to a true circle.

In this embodiment, by adjusting the position of the correction optical component 51 (FIG. 4), the beam profile at the reference position 63 can be made close to a true circle. Since the beam cross section at the reference position 63 is close to a true circle, the surface of the object 90 also has a beam cross section close to a true circle, and a circular hole can be formed.

In addition, in this embodiment, even if the correction optical component 51 ( FIG. 4 ) is moved, the optical path length of the laser beam from the laser oscillator 12 to the condensing optical component 55 does not change. Therefore, the movement of the correction optical component 51 does not affect the propagation state of the laser beam other than the divergence and convergence of the laser beam in the yz plane ( FIGS. 5A and 5B ). Thereby, the number of parameters to be adjusted in order to make the beam profile close to a true circle can be suppressed, and adjustment can be easily performed.

Next, a modification of the above-described embodiment will be described. In the above-mentioned embodiment, the cylindrical concave mirror 52 ( FIG. 4 ) is used for the correction optical component 51 , but a cylindrical convex mirror may be used instead of the cylindrical concave mirror 52 . That is, the correction optical component 51 may include a cylindrical mirror. Alternatively, a cylindrical convex lens or a cylindrical concave lens may be used instead of the cylindrical concave mirror 52 . In the case of using a cylindrical lens, the flat mirror 53 (FIG. 4) is not required. In this way, as the correction optical component 51, an optical component having a cylindrical reflecting surface or a refracting surface may be used. In addition, in the above-mentioned embodiment, the concave mirror is used as the condensing optical component 55, but a convex lens may be used instead of the concave mirror.

In the above-mentioned embodiment, the beam shaping optical device 50 ( FIG. 1 ) is mounted on the laser processing device for drilling, but it can also be mounted on other laser processing devices. In particular, it is possible to obtain a large effect by mounting it on a laser processing apparatus which is required to be processed so that the beam cross section is close to a true circle. In addition, a carbon dioxide laser is used as the laser oscillator 12, but the beam shaping optical device 50 of the above-described embodiment may be combined with other various laser oscillators.

In the above-mentioned embodiment, the laser beam is reflected by the cylindrical concave mirror 52 (FIG. 4) and then incident on the plane mirror 53, but the positions of the two can be replaced. That is, the laser beam output from the laser oscillator 12 may be reflected by the plane mirror 53 , and the reflected light may be incident on the cylindrical concave mirror 52 .

In the above embodiment, the control device 70 controls the supporting mechanism 65 to move the correcting optical component 51 , but the correcting optical component 51 can also be moved by manually adjusting the supporting mechanism 65 by the user.

In the above embodiment, the correcting optical part 51 is arranged on the path of the laser beam between the laser oscillator 12 and the condensing optical part 55 , but the positions of the correcting optical part 51 and the condensing optical part 55 can also be changed relation. That is, the condensing optical component 55 may be arranged on the path of the laser beam between the laser oscillator 12 and the correction optical component 51 . In this case, by changing the optical path length of the laser beam between the correction optical component 51 and the condensing optical component 55, the beam profile at the reference position 63 can also be brought close to a true circle.

Next, referring to FIGS. 6A to 6C , beam shaping optical devices of other embodiments will be described. Hereinafter, the description of the structure common to the beam shaping optical device of the embodiment shown in FIG. 1 to FIG. 5C is omitted.

6A is a perspective view of the cylindrical concave mirror 52 of the beam shaping optical device of the present embodiment, the optical axis 30A of the laser beam incident on the cylindrical concave mirror 52 and the optical axis 30B of the reflected laser beam. The beam shaping optical device 50 of this embodiment includes a posture adjustment mechanism 67 . The posture adjustment mechanism 67 changes the circle by taking the bisector of the angle formed by the optical axis 30A of the laser beam incident on the cylindrical concave mirror 52 and the optical axis 30B of the laser beam reflected by the cylindrical concave mirror 52 as the rotation center 35 . The posture of the cylindrical concave mirror 52 in the rotational direction. The rotation center 35 is perpendicular to the reflection surface of the cylindrical concave mirror 52 .

Next, the excellent effects of the present embodiment will be described with reference to FIGS. 6B and 6C . 6B is a diagram showing a change in the shape of the beam cross section 33 when the correction optical component 51 is moved when the generatrix of the cylindrical concave mirror 52 is parallel to the x-axis. Since the generatrix of the cylindrical concave mirror 52 is parallel to the x-axis, when the correction optical component 51 is moved, the beam profile 33 expands and contracts in the y-direction. When the long axis of the beam profile shown by the dotted line before roundness adjustment is inclined with respect to the y direction, the beam profile 33 does not become a true circle even if the beam profile 33 is expanded or contracted in the y direction.

When the posture in the rotation direction of the cylindrical concave mirror 52 is changed, the direction in which the beam cross section 33 expands and contracts by moving the correcting optical component 51 is inclined with respect to the y direction.

FIG. 6C is a diagram showing a change in the shape of the beam cross section 33 when the direction of expansion and contraction of the beam cross section 33 is inclined with respect to the y direction. The posture in the rotation direction of the cylindrical concave mirror 52 is adjusted so that the direction of expansion and contraction coincides with the long axis direction of the beam cross section shown by the dotted line. Therefore, by arranging the cylindrical concave mirror 52, the beam profile 33 contracts in the direction of the long axis of the beam profile shown by the dotted line. By adjusting the amount of contraction of the beam profile 33 by moving the correction optical component 51, the beam profile 33 can be brought close to a true circle.

The above-mentioned embodiments are examples, and it is self-evident that the structures shown in different embodiments can be partially replaced or combined. According to the same function and effect based on the same structure of a plurality of embodiments, it is not described in each embodiment one by one. Moreover, the present invention is not limited to the above-described embodiments. For example, it is obvious for those skilled in the art that various modifications, improvements, combinations, etc. can be made.

11: Bench 12: Laser oscillator 15: Chamber 16: Optical Room 17: Blower room 18: Upper and lower dividers 18A, 18B: Opening 19: Bottom plate 20A: Optical axis 21: Discharge electrode 22: Electrode Box 23: Electrode support member 24: Discharge area 25: Resonator lens 26: Resonator base 27: Optical resonator support member 28: Translucent window 29: Blower 30, 30A, 30B: Optical axis of the laser beam 31: Laser Beam 32: Beam profile at the exit of the laser oscillator 33: Beam profile at reference position 35: Center of Rotation 40: Divider 41: 1st gas flow path 42: Second gas flow path 43: Heat Exchanger 45: Support part 50: Beam shaping optics 51: Correcting Optical Parts 52: Cylindrical concave mirror 53: Flat mirror 55: Condensing Optical Parts 56: Flat mirror 60: Beam Expander 61: Orifice 62: Flat mirror 63: Reference position 65: Supporting mechanism 66: Detector 67: Posture adjustment mechanism 70: Controls 80: Processing device 81: Beam Scanner 82: fθ lens 85: Workbench 90: Processing object 100: Common base

FIG. 1 is a schematic diagram of a laser processing apparatus equipped with the beam shaping optical apparatus of this embodiment. [ Fig. 2 ] is a cross-sectional view including the optical axis of the laser oscillator. Fig. 3 is a cross-sectional view perpendicular to the optical axis of the laser oscillator of the embodiment. Fig. 4 is a schematic diagram of the beam shaping optical device of the embodiment. In FIG. 5 , FIGS. 5A to 5C are schematic diagrams showing the divergence and convergence of the laser beam when the laser beam is assumed to travel straight without considering the bending of the path caused by the reflection of the laser beam. In FIG. 6, FIG. 6A is a perspective view of a cylindrical concave mirror, an optical axis of an incident laser beam, and an optical axis of a reflected laser beam of a beam shaping optical device according to another embodiment, and FIG. 6B is a cylindrical concave mirror. Figure 6C shows the change in the shape of the beam profile when the direction of expansion and contraction of the beam profile is inclined with respect to the y-direction when the generatrix is parallel to the x-axis. picture.

12: Laser oscillator

50: Beam shaping optics

51: Correcting Optical Parts

52: Cylindrical concave mirror

53: Flat mirror

55: Condensing Optical Parts

56: Flat mirror

60: Beam Expander

61: Orifice

62: Flat mirror

63: Reference position

65: Supporting mechanism

66: Detector

70: Controls

81: Beam Scanner

82: fθ lens

85: Workbench

90: Processing object

Claims (7)

A beam shaping optical device is provided with: Correction optics, which are arranged on the path of the laser beam and include a cylindrical lens or a cylindrical lens; A condensing optical component, which is disposed on the path of the laser beam passing through the correction optical component, and is composed of a convex lens or a concave mirror; and The supporting mechanism supports the correcting optical component movably in the direction of changing the optical path length of the laser beam between the correcting optical component and the condensing optical component. The beam shaping optical device of claim 1, wherein, The aforementioned correction optical parts include cylindrical concave mirrors and flat mirrors; The optical axis of the laser beam on the incident side of the aforementioned correction optical component is parallel to the optical axis of the laser beam on the exit side; The support mechanism supports the correction optical component movably in a direction parallel to the optical axis of the laser beam on the incident side and the exit side while maintaining the relative positional relationship between the cylindrical concave mirror and the flat mirror. The beam shaping optical device as claimed in claim 2, further comprising: A posture adjustment mechanism that changes the circle by taking the bisector of the angle formed by the optical axis of the laser beam incident on the cylindrical concave mirror and the optical axis of the laser beam reflected by the cylindrical concave mirror as the center of rotation The posture of the rotation direction of the cylindrical concave mirror. The beam shaping optical device according to any one of claim 1 to claim 3, further comprising: a detector for detecting the shape of the beam profile at the reference position of the path of the laser beam after passing through the correction optical part and the condensing optical part; and A control device operates the support mechanism so that the shape of the beam cross-section detected by the detector is close to a true circle, and moves the correction optical part. The beam shaping optical device as claimed in claim 4, further comprising: a beam expander disposed on the path of the laser beam passing through the reference position; and an aperture, which is arranged on the path of the laser beam after passing through the beam expander, The beam expander transfers the beam profile of the laser beam at the reference position to the position of the aperture. A method for adjusting roundness, comprising the steps of: The laser beam is condensed to the reference position through correction optical parts including cylindrical mirrors or cylindrical lenses and condensing optical parts composed of convex lenses or concave mirrors, The optical path length of the laser beam between the correction optical part and the condensing optical part is changed, so that the beam profile of the laser beam at the reference position is close to a true circle. The roundness adjustment method according to claim 6, wherein, The aforementioned correction optical parts include cylindrical concave mirrors, Furthermore, taking the bisector of the angle formed by the optical axis of the laser beam incident on the cylindrical concave mirror and the optical axis of the laser beam reflected by the cylindrical concave mirror as the center of rotation, the angle of the cylindrical concave mirror is changed. The posture in the direction of rotation makes the beam profile of the laser beam at the reference position close to a true circle.

Images