TWI781657B - Beam shaping optical device and roundness adjustment method - Google Patents

Abstract

[Problem] Provide a beam shaping optical device that can make the beam profile close to a true circle. [Solution] A correcting optical component including a cylindrical mirror or a cylindrical lens is arranged on the path of the laser beam. On the path of the laser beam passing through the correction optical part, a converging optical part composed of a convex lens or a concave mirror is arranged. The support mechanism movably supports the correction optics in the direction of changing the optical path length of the laser beam between the correction optics and the condensing optics.

Description

Beam shaping optical device and method for adjusting roundness

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

A conventional laser processing device for drilling holes in objects to be processed such as substrates will be described. The laser beam output from the laser oscillator is guided to the concave mirror and condensed to a predetermined size at the position of the transfer source of the beam expander. The beam expander transfers the beam profile at the location of the transfer source to the location of the aperture. The laser beam whose beam profile is substantially circular through the aperture enters the surface of the object to be processed through the Galvano scanner and the fθ lens.

In order to form a circular hole in an object to be processed, it is desired to increase 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 body. For example, when a circular body is sandwiched between two concentric geometric circles, it can be represented by the difference in radius between the two concentric 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. In the following patent document 1, a laser oscillator is disclosed, which realizes the true beam pattern by arranging mirrors with different curvature radii in the two orthogonal directions in the optical resonator of the laser beam. Improvement of circularity. [Prior Art Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2017-34055

In a conventional device, the 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 to be processed may be deformed from the circle. 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 lateral direction.

[Problem to be solved by the invention]

The object of the present invention is to provide a beam shaping optical device and a method for adjusting the true circularity that can make the beam profile close to a true circle. [Technical means to solve the problem]

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

According to another aspect of the present invention, a method for adjusting the roundness is provided, which includes the following steps: Concentrating the laser beam to the reference position through correcting optical parts including cylindrical mirrors or cylindrical lenses and converging optical parts composed of convex lenses or concave mirrors, Changing the optical path length of the laser beam between the correction optical part and the condensing optical part makes the beam profile of the laser beam at the reference position close to a true circle. [Effect of Invention]

If correcting optical components are arranged, one of the divergence angles of the beams in two directions perpendicular to the optical axis of the laser beam is fixed and the other is changed. By changing the optical path length between the correcting optical part and the converging 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 , the beam shaping optical device of 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 the present embodiment. The laser processing device includes a laser oscillator 12 , a processing device 80 and a control device 70 .

The laser oscillator 12 is supported on a stand 11 , and the stand 11 is fixed on a common base 100 . The processing device 80 includes a beam shaping optical device 50 , a beam scanner 81 , an fθ lens 82 and a workbench 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 table 85 are supported on a 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 is shaped by the beam shaping optical device 50 , and enters the object 90 through 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 to be processed 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 makes the pulsed laser beam incident on a desired position of the object 90 to perform drilling. When the scannable range of the pulsed laser beam does not cover the entire area of the surface of the object to be processed 90, the object to be processed 90 can be moved by the table 85 to scan substantially the entire area of the surface of the object to be processed 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 containing a laser medium gas, an optical resonator 20 and the like. The laser medium gas is accommodated 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 located relatively on the lower side. Optical chamber 16 and blower chamber 17 are partitioned by upper and lower partition plates 18 . In addition, an opening through which laser medium gas flows between the optical chamber 16 and the blower chamber 17 is provided on the upper and lower partition plates 18 . 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 , and the optical chamber 16 is longer in the optical axis direction than the blower chamber 17 in the optical axis direction.

The floor 19 of the chamber 15 is supported on the stand 11 ( FIG. 1 ) at four support points 45 . The four support portions 45 are arranged at positions corresponding to four vertices of a 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 on the electrode box 22 . A pair of electrode boxes 22 are supported on the bottom plate 19 via a plurality of electrode support members 23 . A pair of discharge electrode 21 is arrange|positioned at intervals in the up-down direction, and the discharge region 24 is defined between them. The discharge electrode 21 generates a discharge in the discharge region 24, thereby exciting the laser medium gas. A pair of resonator mirrors 25 constitutes an optical resonator 20 having an optical axis 20A passing through the discharge region 24 . As will be described later with reference to FIG. 3 , the laser medium gas flows through the discharge region 24 in a direction perpendicular to the paper surface of FIG. 2 .

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

A translucent window 28 through which the laser beam passes is installed at the intersection of the extension line extending the optical axis 20A of the optical resonator 20 in one direction (left direction 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 explained 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 an upper and lower partition plate 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 on the electrode box 22 . The electrode box 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 a 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 , so 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 the first gas flow path 41 from the opening 18A provided in the upper and lower partition plate 18 to the discharge area 24 and the first gas flow path 41 from the discharge area 24 to the other opening 18B provided in the upper and lower partition plate 18 . 2 Gas flow path 42. Laser dielectric gas flows through discharge region 24 in a direction perpendicular to optical axis 20A (FIG. 2). The discharge direction is perpendicular to both the flow direction of the laser medium gas and the optical axis 20A. A circulation path for circulating the laser medium gas 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 air blower 29 generates the laser medium gas flow indicated by the arrow, so that the laser medium gas circulates in the circulation path.

A heat exchanger 43 is housed 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 the beam shaping optical device 50 of the embodiment. The beam shaping optical device 50 includes a correcting optical component 51 , a converging optical component 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 plane mirror 53 . The condensing optical part 55 is a concave mirror having a spherical or parabolic reflective surface.

The laser beam output from the laser oscillator 12 is reflected by the cylindrical concave mirror 52 , further reflected by the plane mirror 53 , and enters the condensing optical part 55 . The laser beam reflected by the condensing optical part 55 is reflected by the plane mirror 56 and enters the beam expander 60 . The beam expander 60 transfers the beam profile at 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 diameter of the beam. 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 circle. The laser beam passing through the aperture 61 is reflected by the plane mirror 62 and enters the beam scanner 81 . As the beam scanner 81, for example, a galvano scanner is used. 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 forms an image of the aperture 61 on the surface of the object 90 to be processed.

The support mechanism 65 movably supports the correction optics 51 along the optical axis of the laser beam between the correction optics 51 and the condensing optics 55 . The correcting optics 51 move in translation as indicated by the double arrows in FIG. 4 . The shifted correction optics 51 are shown in dashed lines. The optical axis of the laser beam incident on the correcting optical part 51 is parallel to the optical axis of the laser beam from the correcting optical part 51 toward the condensing optical part 55 . The supporting mechanism 65 moves the correction optical part 51 while maintaining the relative positional relationship between the cylindrical concave mirror 52 and the flat mirror 53 . Therefore, even if the correction optics 51 is moved, the optical path length of the laser beam from the laser oscillator 12 to the condensing optics 55 does not change.

The detector 66 is movable between a reference position 63 on the path of the laser beam and a position off 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 by a dotted line, and the detector 66 at a position deviated from the path of the laser beam is shown by 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 by 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, the divergence and convergence of the laser beam in the beam shaping optical device 50 and the shape of the beam cross section will be described with reference to FIGS. 5A to 5C .

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 go straight without considering the bending of the path caused by the reflection of the laser beam. Define the xyz orthogonal coordinate system, set the direction parallel to the generatrix of the cylindrical surface of the cylindrical concave mirror 52 (Fig. for the z direction. For example, the x direction corresponds to the direction in which the pair of discharge electrodes 21 ( FIG. 2 ) separate (discharge direction), and the y direction corresponds to the direction in which the laser medium gas flows in the discharge region 24 ( FIG. 3 ).

5A and 5B show the divergence and convergence of the laser beam on the yz plane. In FIG. 5A and FIG. 5B , the position of the cylindrical concave mirror 52 is different. In FIG. 5B, the same state as that shown in FIG. 5A is shown by dotted lines. 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 section, and coincides with 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 part 55 . In this embodiment, at the exit of the laser oscillator 12 , the beam profile 32 of the laser beam 31 is an ellipse long in the x direction. Also, 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 plane mirror without affecting the convergence and divergence of the laser beam 31 .

The dotted line shown in FIG. 5A shows the state of 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, as shown by the dotted line in FIG. 5A, becomes long in the y direction. oval.

If the cylindrical concave mirror 52 is arranged, the laser beam 31 will converge in the yz plane, and the divergence and convergence of the laser beam 31 in the zx plane will not be affected. Consequently, the size of the beam profile 33 at the reference position 63 decreases in the y-direction. In the state shown in FIG. 5A , the contraction amount of the beam profile 33 in the y direction becomes too large, and the beam profile 33 becomes an ellipse long in the x direction as indicated by the solid line.

As shown in FIG. 5B , when the cylindrical concave mirror 52 is moved toward the converging optical component 55 , the converging 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 shown by the solid line in FIG. 5A . As shown in FIG. 5B and FIG. 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 functions 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 correcting 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 current beam cross-section and the true circle is within an allowable range, the control device 70 stops the correction optical component 51 .

Next, the excellent effects of this embodiment will be described. According to the evaluation experiment of the inventors of the present application, it is clear that if the beam profile of the reference position 63 ( FIG. 4 ) serving as the transfer source of the beam expander 60 deviates from a true circle, even if the beam profile is shaped into a true circle by using the aperture 61 The shape of the processed hole also deviates from a true circle. This is because, even if the profile of the beam profile is only 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 perpendicular to the optical axis. It is known that if the beam profile at the reference position 63 is made close to a true circle, the processed hole 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 profile at the reference position 63 is close to a true circle, the beam profile is also close to a true circle on the surface of the object 90 to be processed, and a circular hole can be formed.

Also, 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 ). This suppresses the number of parameters that should be adjusted in order to bring the beam profile closer to a true circle, and enables easy adjustment.

Next, modifications of the above-described embodiment will be described. In the above embodiment, the correcting optical part 51 uses the cylindrical concave mirror 52 ( FIG. 4 ), but a cylindrical convex mirror may be used instead of the cylindrical concave mirror 52 . That is, the correcting 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 cylindrical lenses, the plane mirror 53 (FIG. 4) is not required. In this way, as the correcting optical component 51, an optical component having a cylindrical reflective surface or a refractive surface may be used. In addition, in the above-mentioned embodiment, a concave mirror was used as the condensing optical component 55, but a convex lens may be used instead of the concave mirror.

In the above embodiments, the beam shaping optical device 50 ( FIG. 1 ) is mounted on a laser processing device for drilling, but it may also be mounted on other laser processing devices. In particular, a large effect can be obtained by mounting it on a laser processing device that requires processing such that the beam profile is close to a true circle. In addition, although a carbon dioxide laser is used as the laser oscillator 12, it is also possible to combine the beam shaping optical device 50 of the above-mentioned embodiment 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 enters the flat mirror 53. However, the positions of the two can also be replaced. That is, a 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 embodiments, 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 the user manually adjusting the supporting mechanism 65 .

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

Next, referring to FIG. 6A to FIG. 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 FIGS. 1 to 5C will be omitted.

6A is a perspective view of the cylindrical concave mirror 52 of the beam shaping optical device of this 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 takes 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, and changes the circle The posture of the rotation direction of the cylindrical concave mirror 52. The center of rotation 35 is perpendicular to the reflective surface of the cylindrical concave mirror 52 .

Next, referring to FIG. 6B and FIG. 6C , the excellent effect of this embodiment will be described. FIG. 6B is a diagram showing changes in the shape of the beam profile 33 when the correcting 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 major axis of the beam profile shown by the dotted line before the roundness adjustment is inclined relative to the y direction, the beam profile 33 will not become a perfect circle even if the beam profile 33 is expanded and contracted in the y direction.

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

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

The above-mentioned embodiments are examples, and it is self-evident that partial replacement or combination of structures shown in different embodiments can be performed. According to the same function and effect based on the same structure of multiple embodiments, it is not described in each embodiment. Also, the present invention is not limited to the above-described embodiments. For example, it is obvious to those skilled in the art that various changes, improvements, combinations, etc. can be made.

11: Bench 12:Laser oscillator 15: chamber 16: Optical room 17: Blower room 18: Upper and lower partitions 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: Light-transmitting 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: Partition board 41: 1st gas flow path 42: Second gas flow path 43: Heat exchanger 45: Support part 50: Beam shaping optics 51:Correction optical parts 52: Cylindrical concave mirror 53: plane mirror 55: Concentrating optical parts 56: plane mirror 60:Beam Expander 61: Orifice 62: plane mirror 63: Reference position 65: Support mechanism 66: detector 67: Posture adjustment mechanism 70: Control device 80: Processing device 81: beam scanner 82: fθ lens 85:Workbench 90: Object to be processed 100: common base

[ Fig. 1 ] is a schematic diagram of a laser processing device equipped with the beam shaping optical device of this embodiment. [Fig. 2] is a sectional view including the optical axis of the laser oscillator. [ Fig. 3 ] is a 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], FIG. 5A-FIG. 5C are schematic diagrams showing the divergence and convergence of the laser beam when the laser beam is assumed to go straight without considering the bending of the path caused by the reflection of the laser beam. [Fig. 6], Fig. 6A is a perspective view of the cylindrical concave mirror, the optical axis of the incident laser beam and the optical axis of the reflected laser beam of the beam shaping optical device of other embodiments, and Fig. 6B is a perspective view of the cylindrical concave mirror In the case where the generatrix is parallel to the x-axis, the change in the shape of the beam profile when the correction optical part is moved, Fig. 6C shows the change in the shape of the beam profile when the direction in which the beam profile expands and contracts is inclined relative to the y direction picture.

12:Laser oscillator

50: Beam shaping optics

51:Correction optical parts

52: Cylindrical concave mirror

53: plane mirror

55: Concentrating optical parts

56: plane mirror

60:Beam Expander

61: Orifice

62: plane mirror

63: Reference position

65: Support mechanism

66: detector

70: Control device

81: beam scanner

82: fθ lens

85:Workbench

90: Object to be processed

Claims (7)

A beam shaping optical device has: Correction optics, which are arranged on the path of the laser beam and include cylindrical mirrors or cylindrical lenses; Concentrating optical parts, which are arranged on the path of the laser beam passing through the aforementioned correcting optical parts, and are composed of convex lenses or concave mirrors; and A support mechanism that movably supports the aforementioned corrective optical component in the direction of changing the optical path length of the laser beam between the aforementioned corrective optical component and the aforementioned condensing optical component. The beam shaping optical device according to claim 1, wherein, The aforementioned correction optical parts include a cylindrical concave mirror and a plane mirror; The optical axis of the laser beam on the incident side of the aforementioned correction optical part is parallel to the optical axis of the laser beam on the outgoing side; The support mechanism movably supports the correcting optical part in a direction parallel to the optical axes of the laser beams on the incident side and the outgoing side while maintaining the relative positional relationship between the cylindrical concave mirror and the plane mirror. The beam shaping optical device according to Claim 2, further comprising: The posture adjustment mechanism takes the bisector of the angle formed by the optical axis of the laser beam incident on the aforementioned cylindrical concave mirror and the optical axis of the laser beam reflected by the aforementioned cylindrical concave mirror as the center of rotation, and changes the aforementioned circle. The pose of the rotation direction of the barrel concave mirror. The beam shaping optical device according to any one of claim 1 to claim 3, further comprising: A detector that detects the shape of the beam profile at the reference position of the path of the laser beam after passing through the aforementioned correction optics and the aforementioned condensing optics; and A control device that operates the support mechanism so that the shape of the cross section of the light beam detected by the detector is close to a true circle, and moves the correction optical part. The beam shaping optical device according to Claim 4, further comprising: a beam expander, which is arranged on the path of the laser beam passing through the aforementioned reference position; and an aperture configured on the path of the laser beam passing through the aforementioned beam expander, The aforementioned beam expander transfers the beam profile of the laser beam at the aforementioned reference position to the position of the aforementioned aperture. A method for adjusting roundness, comprising the steps of: Concentrating the laser beam to the reference position through correcting optical parts including cylindrical mirrors or cylindrical lenses and converging optical parts composed of convex lenses or concave mirrors, Changing the optical path length of the laser beam between the correction optical part and the condensing optical part makes the beam profile of the laser beam at the reference position close to a true circle. The method for adjusting the roundness as described in claim 6, wherein, The aforementioned corrective optics comprise cylindrical concave mirrors, Furthermore, the bisector of the angle formed by the optical axis of the laser beam incident on the aforementioned cylindrical concave mirror and the optical axis of the laser beam reflected by the aforementioned cylindrical concave mirror is used as the center of rotation to change the angle of the aforementioned cylindrical concave mirror. The orientation of the rotation direction, thereby making the beam profile of the laser beam at the aforementioned reference position close to a true circle.

Images