JP7236371B2 - Beam shaper, processing device, and beam shaping method - Google Patents

Description

The present invention relates to a beam shaper, a processing apparatus having the beam shaper, and a beam shaping method.

2. Description of the Related Art In recent years, the market for processing apparatuses that process an object to be processed by sweeping the object while irradiating it with a high-power laser beam generated by a laser light source has been expanding. Examples of processing applications include cutting and welding.

In these processing apparatuses, the temperature of the processing site irradiated with the laser light varies from the temperature before the laser light irradiation (for example, about room temperature) to the temperature after the laser light irradiation (for example, several hundred degrees to several thousand degrees). degree). As a result, in the processing apparatus, spatter is likely to occur due to such a rapid temperature rise.

In order to suppress the occurrence of this spatter, it is believed that preheating of the processed portion is effective. The described laser beam shaping device (which can be read as the processing device of the present invention) can be mentioned. This laser beam shaping device includes an axicon lens, a center lobe with a high peak intensity, a plurality of ring-shaped side lobes formed concentrically with the center lobe and having low intensity, can generate a pseudo-Bessel beam containing

Japanese Unexamined Patent Application Publication No. 2017-142401

By the way, the degree of preheating applied to the object to be processed often differs depending on the material constituting the object to be processed, the purpose of processing, and the like. Therefore, there is a demand for adjusting the ring spacing in a processing apparatus capable of generating a pseudo-Bessel beam.

In order to adjust the ring interval of Bessel beams, a method of changing the axicon lens included in the processing head to another axicon lens having a different vertex angle is conceivable. However, changing the axicon lens included in the processing head to another axicon lens requires time and effort. In addition, preparing a plurality of axicon lenses in order to achieve a plurality of ring intervals leads to an increase in operating costs of the processing apparatus.

SUMMARY OF THE INVENTION One aspect of the present invention has been made in view of the above-described problems, and an object thereof is to provide a beam shaper in which the ring interval can be adjusted without exchanging the axicon lens.

In order to solve the above problems, a beam shaper according to aspect 1 of the present invention includes an axicon lens, and a Bessel beam emitted from the axicon lens by changing a divergence angle of a Gaussian beam incident on the axicon lens. an adjusting mechanism for adjusting the ring spacing of the beams.

According to the above configuration, the adjustment mechanism can be used to adjust the ring spacing of the Bessel beam, so a beam shaper capable of adjusting the ring spacing can be provided without exchanging the axicon lens.

In the beam shaper according to aspect 2 of the present invention, in addition to the configuration of the beam shaper according to aspect 1, the following configuration is adopted. That is, it further includes a collimator lens arranged on the optical path of the Gaussian beam, and the adjustment mechanism maintains the distance from the collimator lens to the axicon lens, and adjusts the collimator from the exit point of the Gaussian beam. A configuration is employed to change the divergence angle by changing the distance to the lens.

According to the above configuration, it is possible to easily adjust the ring interval.

In the beam shaper according to aspect 3 of the present invention, in addition to the configuration of the beam shaper according to aspect 2, the following configuration is adopted. That is, a configuration is adopted in which the emission point is the emission end of an optical fiber that emits the Gaussian beam.

According to the above configuration, a Gaussian beam generated by a laser light source and guided by an optical fiber can be easily converted into a Bessel beam.

In the beam shaper according to aspect 4 of the present invention, in addition to the configuration of the beam shaper according to aspect 3, the following configuration is adopted. That is, the adjustment mechanism includes a lens holder and a slide portion, and the lens holder holds each of the collimator lens and the axicon lens while maintaining the distance from the collimator lens to the axicon lens. Further, the slide portion is adapted to change the distance from the output end to the collimating lens by sliding at least one of the lens holder and the output end.

Like the above configuration, specific configurations of the adjustment mechanism include a lens holder and a slide portion.

In the beam shaper according to aspect 5 of the present invention, in addition to the configuration of the beam shaper according to any one of aspects 1 to 4, the following configuration is adopted. That is, a configuration is adopted in which the adjustment range of the divergence angle by the adjustment mechanism includes both the divergence angle at which the Gaussian beam becomes convergent light and the divergence angle at which the Gaussian beam becomes divergent light.

According to the above configuration, compared to the case where the adjustment range of the divergence angle includes only one of the divergence angle at which the Gaussian beam converges and the divergence angle at which the Gaussian beam diverges, The divergence angle can be adjusted over a wider range. Therefore, the beam shaper can adjust the ring spacing over a wider range.

A processing apparatus according to aspect 6 of the present invention is a processing apparatus comprising the beam shaper according to any one of aspects 1 to 5, wherein the beam shaper emits the Bessel beam.

According to the above configuration, the adjustment mechanism can be used to adjust the ring spacing of the Bessel beams, so it is possible to provide a processing apparatus capable of adjusting the ring spacing without exchanging the axicon lens.

In the processing apparatus according to aspect 7 of the present invention, in addition to the configuration of the processing apparatus according to any of aspects 6, light in the vicinity of at least the irradiation point irradiated with the Bessel beam on the surface of the object to be processed is It further comprises a photodetector that detects the light, and a controller that performs feedback control on the adjustment mechanism according to the light detected by the photodetector.

According to the above configuration, it is possible to adjust the ring interval according to the light in the vicinity of the irradiation point while processing the object to be processed. Therefore, the ring spacing of the Bessel beams emitted from the axicon lens can be preferably maintained over the entire period of processing.

In the processing apparatus according to aspect 8 of the present invention, in addition to the configuration of the processing apparatus according to any one of aspects 7, the following configuration is adopted. That is, the photodetector is a camera that captures an image of the vicinity of the irradiation point, and the control unit performs feedback control on the adjustment mechanism according to the image of the vicinity of the irradiation point that is captured by the camera. configuration is adopted.

According to the above configuration, it is possible to adjust the ring interval according to the state in the vicinity of the irradiation point while processing the object to be processed. Therefore, the ring spacing of the Bessel beams emitted from the axicon lens can be preferably maintained over the entire period of processing.

In order to solve the above problems, a beam shaping method according to aspect 9 of the present invention changes the divergence angle of a Gaussian beam incident on an axicon lens, so that the ring interval of the Bessel beam emitted from the axicon lens is includes an adjustment step of adjusting the

This beam shaping method including such an adjustment process can adjust the ring spacing of the Bessel beam by changing the divergence angle, so the ring spacing can be adjusted without exchanging the axicon lens. .

A beam shaping method according to a tenth aspect of the present invention employs the following configuration in addition to the beam shaping method according to the ninth aspect. That is, the adjustment step is performed by changing the distance from the exit point of the Gaussian beam to the collimating lens while maintaining the distance from the collimating lens arranged on the optical path of the Gaussian beam to the axicon lens. , to change the angle of divergence.

According to the above configuration, it is possible to easily adjust the ring interval.

According to one aspect of the present invention, it is possible to provide a beam shaper in which the ring interval can be adjusted without exchanging the axicon lens.

(a) is a block diagram showing the configuration of a processing apparatus according to an embodiment of the present invention, and (b) is a cross-sectional view of a processing head provided in the processing apparatus shown in (a). (a) to (c) are cross-sectional views of the processing head shown in (a) of FIG. 1, and are cross-sectional views showing the arrangement of a collimator lens and an axicon lens inside the processing head. Each of (a) to (c) is a graph showing the beam intensity distribution of the Bessel beam corresponding to the arrangement of the collimator lens and the axicon lens shown in (a) to (c) of FIG. 2, respectively. 4 is a graph showing the intensity distribution of Bessel beams emitted from the processing head according to the embodiment of the present invention;

(Configuration of processing equipment)
A configuration of a processing apparatus 1 according to one embodiment of the present invention will be described with reference to FIG. In FIG. 1, (a) is a block diagram showing the configuration of the processing device 1, and (b) is a cross-sectional view of a processing head 13 provided in the processing device 1. As shown in FIG.

A processing apparatus 1 is an apparatus for processing an object W, which is an object to be processed, using laser light. As shown in FIG. 13 , a camera 14 and a control unit 15 .

The laser light source 11 is a device that generates laser light. The delivery fiber 12 is an optical fiber that guides the laser light generated by the laser light source 11 . The processing head 13 is a device that irradiates the object W with laser light guided through the delivery fiber 12 . The camera 14 is an example of a photodetector that detects light in the vicinity of an irradiation point irradiated with at least a Bessel beam, which will be described later, on the surface of the object W, and is a device that captures an image of the vicinity of the irradiation point. In this case, the light in the vicinity of the irradiation point is the reflected light obtained by mainly reflecting ambient light surrounding the object W in the vicinity of the irradiation point. Another example of the photodetector is a photodiode. In this case, the light in the vicinity of the irradiation point is light caused by plasma generated in the vicinity of the irradiation point as the object is irradiated with the Bessel beam. In this case, when a photodiode is employed as the photodetector, a filter that transmits light within a predetermined wavelength range may be provided between the irradiation point and the photodiode.

In one aspect of the present invention, the control unit 15 is a device that controls the processing head 13 so as to perform feedback control according to the light in the vicinity of the irradiation point detected by the photodetector to an adjustment mechanism, which will be described later. In this embodiment, the control unit 15 performs feedback control during processing according to the state near the irradiation point based on the image (moving image or still image) near the irradiation point captured by the camera 14. It is a device for controlling the machining head 13 as follows.

In addition, although the control content of the said feedback control is not limited, the following examples are mentioned. During processing performed by sweeping the laser beam, the camera 14 photographs the vicinity of the irradiation point irradiated with the laser beam and generates an image thereof. After obtaining the image from the camera 14, the control unit 15 generates spatter amount information indicating the amount of spatter per unit time based on the image. The control unit 15 further increases or decreases the distance D1 (see FIGS. 1 and 2), which is the distance from the exit point of the Gaussian beam to the collimating lens, according to the spatter amount indicated by the spatter amount information. to any one of When the spatter amount increases by changing the distance D1 by a small amount in this way, the control unit 15 changes the distance D1 by a small amount in the opposite direction (decrease or increase) to the direction in which the distance D1 was changed by a small amount. . By repeating this, the control unit 15 can reduce the amount of spatter that may occur during processing.

Although the method by which the control unit 15 counts the amount of spatter from the image is not limited, for example, there is a method of counting points in the image where the luminance exceeds a threshold. Further, the function of counting the amount of spatter from the image in the control unit 15 can be replaced by a commercially available spatter counter.

Also, the control unit 15 may use any algorithm to determine the amount of change when increasing or decreasing the distance D1. Algorithms include, for example, numerical calculation algorithms such as the bisection method and the secant method.

Further, when a photodiode is adopted as the photodetector, the following example can be cited as the content of the feedback control. During processing, which is performed by sweeping the laser light, the photodiode detects light in the vicinity of the point of illumination and within a predetermined wavelength range filtered by the filter. This predetermined range is determined, for example, to be an index of the temperature of plasma generated in the vicinity of the irradiation point as a result of irradiating the object to be processed with the Bessel beam. Therefore, the control unit 15 generates temperature information representing the temperature of the plasma from the intensity of light included in the predetermined wavelength range detected by the photodiode. Further, the control unit 15 slightly changes the distance D1 in either the increasing direction or the decreasing direction according to the temperature indicated by the temperature information. When the temperature rises by changing the distance D1 by a small amount in this manner, the control unit 15 changes the distance D1 by a small amount in the opposite direction (decrease or increase) to the direction in which the distance D1 was changed by a small amount. By repeating this, the control unit 15 can keep the temperature of the plasma during processing within a predetermined temperature range (more preferably, keep it constant).

As shown in FIG. 1B, the processing head 13 includes a housing 130, a collimator lens 131, an axicon lens 132, a lens holder 133, an adjustment bolt 134, a protective glass 135, and a gas supply hole. 136 and .

The housing 130 is a cylindrical structure with one end (upper end in FIG. 1) closed and the other end (lower end in FIG. 1) open. The delivery fiber 12 is drawn into the housing 130 through an insertion hole provided in the housing 130 .

A collimating lens 131 for collimating the Gaussian beam is arranged on the optical path of the laser light (because it is a Gaussian beam, hereinafter referred to as such) emitted from the delivery fiber 12 . The collimator lens 131 has a flat entrance surface and a spherical exit surface, and the entrance surface (of the collimate lens 131 ) is arranged to face the exit surface of the delivery fiber 12 . . The optical axis of the collimator lens 131 matches the optical axis of the delivery fiber 12 .

An axicon lens 132 for converting the Gaussian beam into a Bessel beam is arranged on the optical path of the Gaussian beam that has passed through the collimating lens 131 . The axicon lens 132 has a flat entrance surface and a conical exit surface. It is The optical axis of the axicon lens 132 coincides with the optical axes of the delivery fiber 12 and collimator lens 131 . In this embodiment, the optical axis common to the delivery fiber 12, the collimating lens 131, and the axicon lens 132 also coincides with the central axis (also referred to simply as the axis) of the casing 130, which will be described later. This common optical axis is also referred to as the optical axis of the processing head 13 below.

The lens holder 133 is a cylindrical structure with both ends opened, and holds the collimator lens 131 and the axicon lens 132 . The collimator lens 131 and the axicon lens 132 are fixed to the inner surface of the lens holder 133, and the distance D2 between the collimator lens 131 and the axicon lens 132 is kept constant.

A convex portion is formed on the outer surface of the lens holder 133 , and this convex portion fits into a concave portion formed on the inner surface of the housing 130 . The width of the concave portion formed on the inner surface of the housing 130 (the axial width of the housing 130 ) is set wider than the width of the convex portion formed on the outer surface of the lens holder 133 . Therefore, the lens holder 133 can be slid in the axial direction of the housing 130 .

As described above, the concave portion formed on the inner surface of the housing 130 and the convex portion formed on the outer surface of the lens holder 133 are arranged so that the collimator lens 131 and the axicon lens 132 can be positioned while maintaining the distance D2 constant. It is an example of a slide portion that slides parallel to the optical axis of the processing head 13 . In addition, in the slide portion of the present embodiment, a concave portion is formed on the inner surface of the housing 130 and a convex portion is formed on the outer surface of the lens holder 133 . However, in one aspect of the slide portion, a convex portion can be formed on the inner surface of the housing 130 and a concave portion can be formed on the outer surface of the lens holder 133 .

For example, the lens holder 133 moves away from the delivery fiber 12 by increasing the amount of insertion of the adjustment bolt 134 and moves closer to the delivery fiber 12 by decreasing the amount of insertion of the adjustment bolt 134 . Therefore, by increasing or decreasing the insertion amount of the adjustment bolt 134, the distance D2 from the collimator lens 131 to the axicon lens 132 is maintained, and the Gaussian beam is collimated from the exit point (the center point of the exit surface of the delivery fiber 12). The distance D1 to the lens 131 can be changed. Here, the output surface of the delivery fiber 12 is one aspect of the output end of the optical fiber described in the claims. The amount of insertion of the adjusting bolt 134 (that is, the distance D1) can be electrically controlled by the controller 15 by a mechanism (not shown), or can be controlled manually.

A gas that functions as an assist gas in laser processing is supplied to the gas supply hole 136 . The assist gas supplied to the gas supply hole 136 is concentrically sprayed onto the processing portion of the object W from the opened lower end of the housing 130 . The type of gas used as the assist gas can be appropriately selected according to the application of laser processing (for example, cutting, welding, etc.). For example, in the case of cutting, the type of assist gas is preferably oxygen because a combustion action is required, and in the case of welding, the type of assist gas is preferably nitrogen in order to suppress participation. Incidentally, the gas species of the assist gas is not limited to oxygen and nitrogen. In addition to the function described above, the assist gas also has the function of suppressing adhesion of spatters generated during processing to the protective glass 135 .

(function of processing head)
The function of the machining head 13 will be described with reference to FIGS. 2 and 3. FIG. 2A to 2C are cross-sectional views of the processing head 13 including the optical axis, and are cross-sectional views showing the arrangement of the collimator lens 131 and the axicon lens 132 inside the processing head 13. FIG. . 2A to 2C, only the collimating lens 131 and the axicon lens 132 are shown. Also, the z-axis shown in each of FIGS. 2(a) to 2(c) is parallel to the optical axis of the processing head 13 (not shown in each of FIGS. 2(a) to 2(c)). It is defined as Also, the z-axis is defined so that the position corresponding to the output surface of the delivery fiber 12 is the origin. Each of FIGS. 3A to 3C shows the beam intensity distribution of the Bessel beam corresponding to the arrangement of the collimating lens 131 and the axicon lens 132 shown in FIGS. 2A to 2C. It is a graph showing.

In FIG. 2A, the distance D1 is determined so that the Gaussian beam emitted from the delivery fiber 12 passes through the collimating lens 131 and becomes collimated light. That is, the distance D1 matches or substantially matches the focal length of the collimator lens 131 . In this embodiment, the distance D<b>1 is assumed to match the focal length of the collimating lens 131 . Hereinafter, the distance D1 shown in (a) of FIG. 2 is referred to as a reference distance D1.

In (b) of FIG. 2, the distance D1 is set to be shorter than the reference distance D1 described above. Therefore, the light emitted from the delivery fiber 12 and transmitted through the collimator lens 131 becomes divergent light. That is, the spot diameter of the light that has passed through the collimating lens 131 expands as the distance from the exit surface of the collimating lens 131 increases.

In (c) of FIG. 2, the distance D1 is set to be longer than the reference distance D1 described above. Therefore, the light emitted from the delivery fiber 12 and transmitted through the collimator lens 131 becomes convergent light. That is, the spot diameter of the light transmitted through the collimating lens 131 is reduced as the distance from the exit surface of the collimating lens 131 increases.

Further, as described above, in the processing head 13, the distance D2 between the collimator lens 131 and the axicon lens 132 is kept constant. Therefore, the distance D2 is constant in any of FIGS. 2(a) to 2(c).

The exit surface of the axicon lens 132 is composed of two oblique sides of an isosceles triangle when viewed in cross section as shown in FIGS. 2(a) to 2(c). Hereinafter, in each of FIGS. 2A to 2C, of the two oblique sides, the upper oblique side is referred to as the first oblique side, and the lower oblique side is referred to as the second oblique side. . Therefore, as shown in FIG. 2A, when collimated light is incident on the axicon lens 132, the first oblique side refracts the collimated light obliquely downward, and the second oblique side refracts the collimated light. Light is refracted diagonally upward.

As shown in (a) of FIG. 2 , the light refracted obliquely downward by the first oblique side and the light refracted obliquely upward by the second oblique side are refracted from the exit surface of the axicon lens 132 . They intersect in an interference region B, which is a neighboring region, and interfere with each other. In the interference region B, the light refracted obliquely downward by the first oblique side and the light refracted obliquely upward by the second oblique side interfere with each other to form a pseudo Bessel beam. . In this embodiment, when a Bessel beam is described without a particular notice, it means a pseudo-Bessel beam.

The beam shape of a Bessel beam consists of a central lobe located on the optical axis and having the highest beam intensity, and striped side lobes formed symmetrically on both sides of the central lobe (( a) see).

Since each of the collimating lens 131 and the axicon lens 132 has an isotropic shape with respect to the central axis, the beam spot of the Bessel beam also has an isotropic shape with the optical axis as the central axis. That is, the three-dimensional shape of the beam spot of the Bessel beam is obtained by rotating the beam profile shown in FIG. .

Compared to Gaussian beams, Bessel beams can propagate beams over long distances (corresponding to the length of the interference region, typically several millimeters) while suppressing expansion of the beam spot diameter. can. Therefore, since the processing apparatus 1 is provided with the processing head 13, the processing apparatus 1 can irradiate the object W with the Bessel beam. By using a Bessel beam for laser processing, for example, pores with a high aspect ratio can be formed in the object W compared to the case of using a Gaussian beam as a laser beam.

Hereinafter, the distance to the innermost peak among the multiple peaks included in the sidelobes is referred to as distance D22, and the distance to the second innermost peak is referred to as distance D33.

As shown in (b) of FIG. 2, when the distance D1 is set to be shorter than the reference distance D1 shown in (a) of FIG. , the length of the interference region along the optical axis increases. As a result, as shown in FIG. 3(b), the beam spot ring interval of the Bessel beam becomes sparse compared to FIG. 3(a). That is, by setting the distance D1 to be shorter than the reference distance D1, each of the distance D22 and the distance D33 becomes longer than the state shown in FIG. 3(a).

As shown in (c) of FIG. 2, when the distance D1 is set to be shorter than the reference distance D1 shown in (a) of FIG. , the length of the interference region along the optical axis is shortened. As a result, as shown in FIG. 3(c), the ring spacing of the ring structure of the beam spot of the Bessel beam becomes denser than in FIG. 3(a). That is, by setting the distance D1 to be shorter than the reference distance D1, each of the distance D22 and the distance D33 becomes shorter than the state shown in FIG. 3(a).

As described above, the processing head 13 functions as a beam shaper that forms a Bessel beam that irradiates the object W. As shown in FIG. The slide portion, the lens holder 133, and the adjustment bolt 134 change the divergence angle θ of the Gaussian beam incident on the axicon lens 132 (see (b) and (c) in FIG. 2) to change the axicon angle. It functions as an adjustment mechanism that adjusts the ring interval of Bessel beams emitted from the lens 132 .

In this embodiment, the output surface of the delivery fiber 12 is fixed to the processing head 13, and the collimator lens 131 and the axicon lens 132 are fixed to the lens holder 133 while the distance D2 is fixed. The adjusting mechanism slides the lens holder 133 along the optical axis to change the distance D1 while maintaining the distance D2. However, in one aspect of the present invention, the collimator lens 131 and the axicon lens 132 are fixed to the processing head 13, the output surface of the delivery fiber 12 is fixed to the fiber holder, and the adjustment mechanism is an adjustment bolt 134 may be used to slide the fiber folder in the optical axis direction of the processing head 13 to change the distance D1 while maintaining the distance D2. In one aspect of the present invention, the adjustment mechanism changes the distance D1 while maintaining the distance D2 by sliding both the lens holder 133 and the fiber holder in the optical axis direction of the processing head 13. may be configured.

〔Example〕
FIG. 4 shows beam profiles obtained when the distance D1 is changed in the processing head 13 shown in FIG. The plot of D1=0 mm shown in FIG. 4 was obtained when the distance D1 was matched with the reference distance D1 (that is, the state shown in FIG. 2(a)). Also, the plot of D1=-6 mm shown in FIG. 4 was obtained when the distance D1 was 6 mm shorter than the reference distance D1 (that is, an example of the state shown in FIG. 2(b)). , D1=6 mm plots in FIG. 4 are obtained when the distance D1 is 6 mm longer than the reference distance D1 (that is, an example of the state shown in FIG. 2(c)).

Table 1 below shows the distance D22 and the distance D33 when the distance D1 is −6 mm, 0 mm, and 6 mm.

According to Table 1, by making the distance D1 shorter than the reference distance D1, the ring interval becomes sparse, and by making the distance D1 longer than the reference distance D1, the ring interval becomes dense. rice field.

[Additional notes]
The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention.

1 processing device 11 laser light source 12 delivery fiber 13 processing head 130 housing 131 collimator lens 132 axicon lens 133 lens holder (part of adjustment mechanism)
134 adjustment bolt 135 protective glass 136 gas supply hole 14 camera 15 control unit W object (object to be processed)

Claims (10)

an axicon lens,
an adjustment mechanism for adjusting the ring interval of the Bessel beam emitted from the axicon lens by changing the divergence angle of the Gaussian beam incident on the axicon lens.
A beam shaper characterized by: further comprising a collimating lens arranged on the optical path of the Gaussian beam,
The adjustment mechanism changes the divergence angle by changing the distance from the exit point of the Gaussian beam to the collimating lens while maintaining the distance from the collimating lens to the axicon lens.
The beam shaper according to claim 1, characterized in that: The exit point is the exit end of an optical fiber that emits the Gaussian beam,
3. A beam shaper according to claim 2, characterized in that: The adjustment mechanism includes a lens holder and a slide section,
The lens holder holds each of the collimator lens and the axicon lens while maintaining a distance from the collimator lens to the axicon lens,
The slide section changes the distance from the output end to the collimator lens by sliding at least one of the lens holder and the output end.
4. The beam shaper according to claim 3, characterized in that: The adjustment range of the divergence angle by the adjustment mechanism includes both the divergence angle at which the Gaussian beam is converging light and the divergence angle at which the Gaussian beam is diverging light.
The beam shaper according to any one of claims 1 to 4, characterized in that: A processing apparatus comprising the beam shaper according to any one of claims 1 to 5, wherein the beam shaper emits the Bessel beam,
A processing device characterized by: A photodetector that detects light in the vicinity of at least the irradiation point irradiated with the Bessel beam on the surface of the object to be processed;
A control unit that performs feedback control on the adjustment mechanism according to the light detected by the photodetector,
7. The processing apparatus according to claim 6, characterized in that: The photodetector is a camera that images the vicinity of the irradiation point,
The control unit performs feedback control on the adjustment mechanism according to an image in the vicinity of the irradiation point captured by the camera.
8. The processing apparatus according to claim 7, characterized in that: adjusting the ring spacing of the Bessel beam exiting the axicon lens by changing the divergence angle of the Gaussian beam entering the axicon lens;
A beam shaping method characterized by: In the adjustment step, while maintaining the distance from the collimator lens arranged on the optical path of the Gaussian beam to the axicon lens, the distance from the exit point of the Gaussian beam to the collimator lens is changed to adjust the change the divergence angle,
10. The beam shaping method according to claim 9, characterized by:

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