WO2012117569A1

WO2012117569A1 - Laser processing device

Info

Publication number: WO2012117569A1
Application number: PCT/JP2011/056290
Authority: WO
Inventors: 泰成波多
Original assignee: オムロン株式会社
Priority date: 2011-02-28
Filing date: 2011-03-16
Publication date: 2012-09-07
Also published as: TW201235142A; JP2012179612A; JP5348155B2

Abstract

In order to reduce the cross-sectional area of the core of an optical fiber used to transmit laser light, the intensity distribution of the laser light emitted from a laser oscillator (111) is shaped by the optical fiber (115) so as to be virtually uniform. The laser light emitted from the optical fiber (115) is focused by a focus lens (119) and introduced into an optical fiber (120). The laser light entering the optical fiber (120) is transmitted to a processing optical system comprising a collimator lens (121) through an fθ lens (126). The present invention can be applied to a laser processing device, for example.

Description

Laser processing equipment

The present invention relates to a laser processing apparatus, and more particularly, to a laser processing apparatus that transmits laser light using an optical fiber.

Conventionally, in a laser processing apparatus, an optical fiber is used to transmit laser light emitted from a laser oscillator to a processing optical system (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2002-16269

The optical fiber can enter a stronger laser beam as the cross-sectional area of the core increases. On the other hand, the price of an optical fiber increases as the cross-sectional area of the core increases. Therefore, in order to increase the intensity of the laser beam and increase the processing energy, it is necessary to increase the cross-sectional area of the core of the optical fiber, which increases the necessary cost.

Also, since the optical fiber deteriorates due to repeated bending and stretching as the processing unit equipped with the processing optical system moves, it needs to be replaced periodically. Therefore, the more expensive the optical fiber, the higher the running cost of the laser processing apparatus.

The present invention has been made in view of such a situation, and makes it possible to reduce the cross-sectional area of the core of an optical fiber for transmitting laser light of a laser processing apparatus.

A laser processing apparatus according to one aspect of the present invention includes a beam shaper that shapes the intensity distribution of laser light emitted from a laser oscillator substantially uniformly, a lens that condenses the laser light emitted from the beam shaper, and a lens. And a first optical fiber that transmits the incident laser light to the processing optical system.

In one aspect of the present invention, the intensity distribution of the laser light emitted from the laser oscillator is shaped almost uniformly by the beam shaper, and the laser light emitted from the beam shaper is condensed by the lens and condensed by the lens. The laser beam thus transmitted is transmitted to the processing optical system by the first optical fiber.

Therefore, the peak intensity of the laser light incident on the first optical fiber for transmission can be reduced, and as a result, the cross-sectional area of the core of the first optical fiber can be reduced.

This beam shaper includes, for example, various beam shapers such as an optical fiber, a homogenizer, and a cylindrical lens.

This beam shaper can be composed of a second optical fiber, where the core diameter of the first optical fiber is φ1, the numerical aperture is NA1, the core diameter of the second optical fiber is φ2, and the numerical aperture is NA2. In this case, φ2> φ1 and NA2 ≦ NA1 × (φ1 / φ2) can be satisfied.

This makes it possible to realize a beam shaper at a low cost.

This beam shaper can be constituted by a second optical fiber in which a rod lens is attached to an end face on the side on which laser light is incident.

Thereby, the cross-sectional area of the core of the second optical fiber used as the beam shaper can be reduced.

The cross sections of the cores of the first optical fiber and the second optical fiber can be rectangular.

Thereby, when the laser beam is scanned on the processing surface, the area where the adjacent light spots are overlapped can be reduced, and as a result, the processing time can be shortened.

According to one aspect of the present invention, the cross-sectional area of the core of the optical fiber for laser beam transmission of the laser processing apparatus can be reduced.

It is a figure which shows the structural example of the optical system of the laser processing apparatus to which this invention is applied. It is a figure which shows the structural example of the external appearance of the laser processing apparatus to which this invention is applied. It is a figure which shows the beam profile and cross-sectional shape of the laser beam before injecting into the optical fiber for beam shaping, and after emission. It is a figure which shows the modification of the optical fiber for beam shaping. It is a figure which shows the modification of the optical system of the laser processing apparatus to which this invention is applied.

Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described. The description will be given in the following order.
1. Embodiment 2. FIG. Modified example

FIG. 1 shows a configuration example of an optical system of a laser processing apparatus 101 to which the present invention is applied.

The laser processing apparatus 101 is an apparatus for processing the processing object 102 using laser light. The workpiece 102 is not particularly limited, and is, for example, a thin film solar cell panel or a display panel.

The laser processing apparatus 101 includes a laser oscillator 111,

total reflection mirrors

112 and 113, a condensing lens 114, an optical fiber 115, a collimator lens 116,

total reflection mirrors

117 and 118, a condensing lens 119, an optical fiber 120, a collimator lens 121, An imaging lens 124,

scan mirrors

125a and 125b, and an fθ lens 126 are included.

The laser oscillator 111 is composed of a laser oscillator that emits pulsed laser light. The laser oscillator 111 is not limited to a specific type, and an arbitrary type can be adopted.

The laser light emitted from the laser oscillator 111 is reflected by the total reflection mirror 112 and the total reflection mirror 113, then collected by the condenser lens 114, and enters the optical fiber 115.

The optical fiber 115 is formed of a square optical fiber having a square cross section, and is used for laser beam shaping. Specifically, the optical fiber 115 shapes the cross-sectional shape of the incident laser light into a square and emits it after making the intensity distribution substantially uniform.

The laser light emitted from the optical fiber 115 is collimated by the collimator lens 116, reflected by the total reflection mirror 117 and the total reflection mirror 117, condensed by the condenser lens 119, and then incident on the optical fiber 120.

As with the optical fiber 115, the optical fiber 120 is composed of a square optical fiber having a square cross section, and is used for transmitting laser light. That is, the optical fiber 120 transmits the incident laser light to a processing optical system including the collimator lens 121 to the fθ lens 126.

The laser light emitted from the optical fiber 120 is collimated by the collimator lens 121, passes through the imaging lens 122, and enters the slit 123. The slit 123 has a square opening, and limits the cross section of the laser beam to the shape of the opening.

The laser light that has passed through the slit 123 passes through the imaging lens 124, is reflected in the direction of the fθ lens 126 by the

scan mirrors

125a and 125b, passes through the fθ lens 126, and forms an image on the processing surface of the workpiece 102. . Further, the scan mirrors 125 a and 125 b and the fθ lens 126 scan the imaging position of the laser beam on the processing surface of the processing object 102, that is, the processing position.

In addition, by shaping the cross section of the laser light into a square and irradiating the processing object 102, for example, when scanning the laser light on the processing surface as compared with the laser light having a circular or elliptical cross section, The area where the adjacent light spots overlap can be reduced. As a result, the processing time can be shortened.

[External configuration example of laser processing apparatus 101]
FIG. 2 schematically illustrates an external configuration example of the laser processing apparatus 101. However, in FIG. 2, the components corresponding to the laser oscillator 111 to the condenser lens 119 in FIG. 1 are not shown.

The laser processing apparatus 101 is configured to include a surface plate 151, a holder 152, a gantry 153, a processing unit 154, a wiring member 155, a holder 156, and cable bears 157a to 157d.

In the following, the direction that is horizontal to the upper surface of the surface plate 151 (the upper surface of the holder 152) and the gantry 153 extends (the left-right direction of the laser processing apparatus 101) is defined as the X-axis direction. In the following description, a direction that is horizontal to the upper surface of the surface plate 151 (the upper surface of the holder 152) and perpendicular to the X axis (the front-rear direction of the laser processing apparatus 101) is defined as the Y-axis direction. Further, hereinafter, a direction (vertical direction of the laser processing apparatus 101) perpendicular to the X axis and the Y axis is defined as a Z axis direction.

In the following, in the X-axis direction, the side whose side is visible in the figure is the right side of the laser processing apparatus 101, and the opposite side is the left side. In the following, in the Y-axis direction, the side where the gantry 153 is located in the figure is the rear side of the laser processing apparatus 101, and the opposite side is the front side.

A holder 152 is installed on the upper surface of the surface plate 151, and the workpiece 102 is placed on the upper surface of the holder 152. In addition, on the upper surface of the surface plate 151, a guide 151A1 and a guide 151A2 (not shown) are provided on both the left and right sides of the holder 152 so as to extend in the Y-axis direction.

The gantry 153 is installed on the guides 151A1 and 151A2 so that the beam (beam) extends in the X-axis direction, and can move in the Y-axis direction according to the guides 151A1 and 151A2. A guide 153A is provided on the upper surface of the gantry 153 so as to extend in the X-axis direction.

The processing unit 154 includes a collimator lens 121 to an fθ lens 126 and is a unit for emitting a laser beam and processing the workpiece 102. The processing unit 154 is supported on the beam of the gantry 153 so as to be movable in the X-axis direction according to the guide 153A. Further, the machining unit 154 moves in the Y axis direction together with the gantry 153.

The wiring member 155 is a member for wiring the optical fiber 120 and the like, and is attached to the right side of the gantry 153.

The holder 156 is attached to the rear side of the gantry 153, and the cable bears 157c and 157d are installed thereon.

Note that the wiring member 155 and the holder 156 move together with the gantry 153 in the Y-axis direction.

The cable bears 157a and 157b are provided for wiring of the optical fiber 120 and the like, and are arranged on the right side of the surface plate 151 so as to extend in the Y-axis direction and be folded up and down. The upper ends of the

cable carriers

157a and 157b are attached to the wiring member 155, and the lower end is fixed to a predetermined position on the right side of the surface plate 151. Therefore, as the gantry 153 moves in the Y-axis direction, the upper ends of the cable bears 157a and 157b move in the Y-axis direction, and the bent positions of the cable bears 157a and 157b move in the Y-axis direction.

The cable bears 157c and 157d are arranged on the upper surface of the holder 156 so as to extend in the X-axis direction and be folded up and down. The upper ends of the cable bears 157 c and 157 d are attached to a part of the processing unit 154, and the lower end is fixed at a predetermined position of the holder 156. Accordingly, as the processing unit 154 moves in the X-axis direction, the upper ends of the cable bears 157c and 157d move in the X-axis direction, and the bending positions of the cable bears 157c and 157d move in the X-axis direction.

Although not shown, the optical fiber 120 is connected to the processing unit 154 through one of the cable bear 157a and the cable bear 157b, the wiring member 155, and the cable bear 157c and the cable bear 157d. Yes. Accordingly, as the position where the cable bearers 157a to 157d bend moves as the machining unit 154 moves in the X-axis direction and the gantry 153 moves in the Y-axis direction, the position where the optical fiber 120 bends also moves. As a result, the optical fiber 120 is deteriorated by being repeatedly bent or stretched, and therefore needs to be periodically replaced.

[Specifications of optical fiber 115 and optical fiber 120]
Here, the specifications of the optical fiber 115 and the optical fiber 120 will be examined with reference to FIG.

FIG. 3 shows an example of the beam profile and cross section of the laser beam on the entrance surface 115A and the exit surface 115B of the core of the optical fiber 115. The left side shows a beam profile and a cross section of laser light (that is, laser light before entering the optical fiber 115) on the incident surface 115A. The right side shows a beam profile and a cross section of laser light (that is, laser light after being emitted from the optical fiber 115) on the emission surface 115B.

The pre-incidence laser light has a circular cross section and an intensity distribution that follows a Gaussian distribution. On the other hand, the emitted laser light has a top-hat type distribution with a substantially square cross section and a substantially uniform intensity distribution. Further, since the intensity distribution is made uniform, the peak intensity of the laser beam is lowered and the power density peak of the laser beam is lowered as compared with that before the incidence.

By the way, the material forming the core of the optical fiber (for example, quartz glass) burns out at the interface with air when the power density of the incident laser light exceeds a predetermined rated value (hereinafter referred to as the rated power density). There is a fear.

Therefore, by reducing the peak intensity of the laser light using the optical fiber 115, it becomes possible to make the stronger (more energy) laser light incident on the optical fiber 120. As a result, a larger processing energy can be obtained.

Conversely, by reducing the peak intensity of the laser light using the optical fiber 115, the laser light incident on the optical fiber 120 in a range where the power density of the laser light incident on the core of the optical fiber 120 is equal to or lower than the rated power density. The peak intensity can be increased by reducing the cross-sectional area. Therefore, the cross-sectional area of the core of the optical fiber 120 can be made smaller than the cross-sectional area of the core of the optical fiber 115 (that is, the cross-sectional area of the core of the optical fiber 120 required when the optical fiber 115 is not provided). As a result, the cost of the optical fiber 120 can be reduced.

Also, it is necessary to prevent energy loss when the laser light emitted from the optical fiber 115 enters the optical fiber 120. For that purpose, the core diameter φa and the numerical aperture NAa of the optical fiber 115 and the core diameter φb and the numerical aperture NAb of the optical fiber 120 may be set so as to satisfy the following expression (1). When the cross section of the core of the optical fiber is rectangular, the core diameter on the emission side can be calculated as the diameter of a rectangular circumscribed circle, and the core diameter on the incident side can be calculated as the diameter of a rectangular inner circle.

NAa × φa ≦ NAb × φb (1)

In summary, in the laser processing apparatus 101, the conditions that the core diameter φa and the numerical aperture NAa of the optical fiber 115 and the core diameter φb and the numerical aperture NAb of the optical fiber 120 should satisfy are expressed by the following equations (2) and (3 )

φa> φb (2)
NAa ≦ NAb × (φb / φa) (3)

For example, the core diameter φa of the optical fiber 115 is set to be twice the core diameter φb of the optical fiber 120, and the numerical aperture NAa of the optical fiber 115 is set to ½ of the numerical aperture NAb of the optical fiber 120. In this case, for example, the focal length of the condenser lens 114 and the condenser lens 119 is set to the same value, and the focal length of the collimator lens 116 is set to twice that of the condenser lens 114 and the condenser lens 119. .

The optical fiber 115 is at least long enough to perform laser beam shaping, that is, the cross-sectional shape of the laser light is square, and is long enough to make the intensity distribution uniform. I just need it. Therefore, the optical fiber 115 can be made sufficiently shorter than the optical fiber 120, although it depends on the specifications such as the wiring path of the optical fiber 120.

As described above, the laser processing apparatus 101 can reduce the cross-sectional area of the core of the optical fiber 120 with respect to laser light having the same intensity as compared with the case where the optical fiber 115 is not used.

Therefore, it is possible to reduce the cost of the transmission optical fiber 120 that needs to be periodically replaced, and to reduce the running cost of the laser processing apparatus 101.

On the other hand, the optical fiber 115 is sufficiently shorter than the optical fiber 120, and is not bent or stretched like the optical fiber 120, so that there is no need for periodic replacement. Further, the optical fiber 115 is less expensive than a beam shaper such as a homogenizer or a cylindrical lens. Therefore, the cost increase due to the provision of the optical fiber 115 is smaller than the cost reduction of the optical fiber 120 described above.

<2. Modification>
Hereinafter, modifications of the embodiment of the present invention will be described.

[Modification 1]
For example, instead of the optical fiber 115, an optical fiber 171 with a rod lens shown in FIG. 4 may be used. The optical fiber 171 with a rod lens is obtained by fusing a cylindrical rod lens 182 to the incident end surface of an optical fiber 181 having a square cross section similar to the optical fiber 115 and the optical fiber 120.

Here, a case where laser light having a power of 200 W and a repetition frequency of 10 kHz is incident on the optical fiber 171 with a rod lens will be considered.

Hereinafter, the rated power density of a material (for example, quartz glass) forming the core 181A, the clad 181B, and the rod lens 182 of the optical fiber 181 is 1.0 MW / mm ² . The core diameter of the optical fiber 181 is 0.35 mm, and the diameter of the cross section of the rod lens 182 is 0.64 mm.

In this case, the pulse energy of the laser beam is 20 mJ (= 200 W ÷ 10 kHz), and the peak power is 0.33 MW (= 20 mJ ÷ 60 ns).

For example, when laser light is directly incident on the optical fiber 181 without passing through the rod lens 182, the peak power density of the laser light incident on the optical fiber 181 is 2.7 MW / mm ² (= 0.33 MW ÷ (0 .35 mm) ² ), which exceeds the rated power density of the optical fiber 181.

On the other hand, when the laser light is incident on the optical fiber 181 through the rod lens 182, the power density of the laser light incident on the rod lens 182 is 1.0 MW / mm ² (= 0.33 MW ÷ {(0.64 mm / 2) ² × π}), and can be suppressed within the rated power density of the rod lens 182.

The laser light incident on the rod lens 182 is condensed so that the radius of the cross section is 0.35 mm or less, and is incident on the core 181A of the optical fiber 181. At this time, the fused surface between the core 181A of the optical fiber 181 and the rod lens 182 does not come into contact with air, and therefore has substantially the same durability as the inside of the material of the core 181A and the rod lens 182. Therefore, there is no fear that the fused surface of the core 181A and the rod lens 182 will be burned out by the laser beam.

Therefore, for example, an optical fiber having the same core diameter and numerical aperture as that of the optical fiber 120 can be used for the optical fiber 181.

Incidentally, when laser light is directly incident on the optical fiber 181 without going through the rod lens 182, for example, when the core diameter is 0.60 mm, the peak power density of the laser light is smaller than the rated power density of the optical fiber 181. .92 MW / mm ² (= 0.33 MW ÷ (0.60 mm) ² ).

As described above, when the optical fiber 171 with the rod lens is used, the cross-sectional area of the core of the optical fiber 181 can be reduced as compared with the case where the optical fiber 115 is used. Further, since the cross-sectional area of the core of the optical fiber 181 is reduced, the distance necessary for beam shaping of the laser light is shortened, and the entire length of the optical fiber 171 with a rod lens can be shortened.

[Modification 2]
Further, an optical fiber with a rod lens may be used as the optical fiber 120 without providing an optical fiber for beam shaping (the optical fiber 115 or the optical fiber with a rod lens 171). That is, as described above, the optical fiber with a rod lens can enter a stronger laser beam than an optical fiber without a rod lens having the same cross-sectional area of the core. Therefore, by using an optical fiber with a rod lens for the optical fiber 120, the cross-sectional area of the core of the optical fiber 120 can be reduced without providing an optical fiber for beam shaping.

[Modification 3]
Furthermore, the cross section of the core of each optical fiber can be any shape other than a square. For example, it can be a rectangle other than a square, or a circle or an ellipse. However, it is desirable to match the shape of the cross section of the core of the optical fiber for beam shaping (the optical fiber 151 or the optical fiber 171 with the rod lens) and the optical fiber 120 for transmission. For example, when the cross-sectional shape of the core of the optical fiber 115 is a rectangle having a ratio of the length of the long side to the short side of 2: 1, the cross-sectional shape of the core of the optical fiber 120 is also the long side and the short side. It is desirable to use a rectangle with a length ratio of 2: 1.

[Modification 4]
In the embodiment of the present invention, various beam shapers such as a homogenizer and a cylindrical lens can be used in addition to the optical fiber 115 and the optical fiber 171 with the rod lens.

[Modification 5]
Furthermore, in the present invention, as described above, the cost reduction effect of the transmission optical fiber 120 is great. Accordingly, the longer the transmission optical fiber 120, the greater the effect of the present invention. Further, for example, as shown in FIG. 5, when the laser light is branched and the laser light is transmitted by a plurality of optical fibers, the effect of the present invention increases as the number of optical fibers for transmission increases.

5 shows a configuration example of the optical system of the laser processing apparatus 201 provided with a branching optical system for branching the laser light into six at the subsequent stage of the collimator lens 116 of the laser processing apparatus 101 of FIG. In the figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. Further, in this drawing, the illustration of the processing optical system is omitted.

The laser processing apparatus 201 includes a laser oscillator 111, a condensing lens 114, an optical fiber 115, a collimator lens 116, a partial mirror 211, a total reflection mirror 212, and branching optical systems 213a to 215b. .

The branching optical system 213a is configured to include a partial mirror 221a, a mechanical shutter 222a, a rotary attenuator 223a, a power splitter 224a, a condenser lens 225a, an optical fiber 226a, and a power monitor 227a.

The branch optical system 213b has the same configuration as the branch optical system 213a. In addition, the code | symbol of each component of the branch optical system 213b replaced the code | symbol of the code | symbol of each component of the branch optical system 213a with b.

The branching optical system 214a is configured to include a partial mirror 231a, a mechanical shutter 232a, a rotary attenuator 233a, a power splitter 234a, a condenser lens 235a, an optical fiber 236a, and a power monitor 237a. The mechanical shutter 232a to power monitor 237a are the same as the mechanical shutter 222a to power monitor 227a of the branch optical system 213a.

The branch optical system 214b has the same configuration as the branch optical system 214a. In addition, the code | symbol of each component of the branch optical system 214b replaces the code | symbol of the code | symbol of each component of the branch optical system 214a with b.

The branching optical system 215a is configured to include a total reflection mirror 241a, a mechanical shutter 242a, a rotor attenuator 243a, a power splitter 244a, a condenser lens 245a, an optical fiber 246a, and a power monitor 247a. The mechanical shutter 242a to power monitor 247a are the same as the mechanical shutter 222a to power monitor 227a of the branch optical system 213a.

The branching optical system 215b has the same configuration as the branching optical system 215a. In addition, the code | symbol of each component of the branch optical system 215b replaces the code | symbol of the code | symbol of each component of the branch optical system 215a with b.

For example, the

partial mirrors

211, 231a, and 231b have a transmittance of 50% and a reflectance of 50%, and the

partial mirrors

221a and 221b have a transmittance of 33% and a reflectance of 67%. It is done.

The laser light emitted from the optical fiber 115 and transmitted through the collimator lens 116 is branched into two by the partial mirror 211.

The laser beam reflected by the partial mirror 211 is reflected by the total reflection mirror 212 and branched into two by the partial mirror 221a of the branching optical system 213a.

The laser light reflected by the partial mirror 221a is attenuated by the rotary attenuator 223a, partially reflected by the power splitter 224a, and the rest is transmitted. The laser light transmitted through the power splitter 224a is collected by the condenser lens 225a, enters the optical fiber 226a, and is transmitted to the corresponding processing optical system by the optical fiber 226a. On the other hand, the laser beam reflected by the power splitter 224a is incident on the power monitor 227a, and its intensity is detected. The power monitor 227a transmits a signal indicating the intensity of the detected laser light to the subsequent stage.

On the other hand, the laser beam transmitted through the partial mirror 221a is branched into two by the partial mirror 231a of the branching optical system 214a.

The laser light reflected by the partial mirror 231a behaves in the same manner as the laser light reflected by the partial mirror 221a of the branching optical system 213a and enters the optical fiber 236a and the power monitor 237a. The laser light incident on the optical fiber 236a is transmitted to the corresponding processing optical system through the optical fiber 236a.

On the other hand, the laser light transmitted through the partial mirror 231a is reflected by the total reflection mirror 241a of the branching optical system 215a, behaves in the same manner as the laser light reflected by the partial mirror 221a of the branching optical system 213a, and the optical fiber 246b. And enters the power monitor 247a. The laser light incident on the optical fiber 246a is transmitted to the corresponding processing optical system through the optical fiber 246a.

On the other hand, the laser light transmitted through the partial mirror 211 is branched into three, similarly to the laser light reflected by the total reflection mirror 212, and is incident on the branch optical system 213b, the branch optical system 214b, and the branch optical system 215b, respectively. To do. Then, the optical fiber 226b, the optical fiber 236b, and the optical fiber 246b are transmitted to the corresponding processing optical systems.

In this way, the laser light emitted from the laser oscillator 111 is branched into six and transmitted to the six processing optical systems through different optical fibers. Therefore, it is possible to perform a maximum of 6 processing simultaneously by the 6 processing optical systems.

The mechanical shutters 222a to 224b can be used to individually stop the emission of the laser light from each branching optical system, and the number of places for processing can be adjusted at the same time.

Thereby, as in the laser processing apparatus described in Patent Document 1 described above, the laser light with a uniform intensity distribution is compared with the case where the laser light is incident on a bundle fiber composed of a plurality of optical fibers. Loss of laser light at the time of branching can be suppressed.

Note that the number of branches of the laser light described above is an example, and can be set to an arbitrary number.

The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 101 Laser processing apparatus 102 Processing object 111 Laser oscillator 114 Condensing lens 115 Optical fiber 116 Collimating lens 119 Condensing lens 120 Optical fiber 121 Collimating lens 122 Imaging lens 123 Slit 124

Imaging lens

125a, 125b Scan mirror 126 f (theta) lens 151 Surface plate 153 Gantry 154 Processing unit 155 Wiring member 157a to 157d Cable bear 171 Optical fiber with rod lens 181 Optical fiber 182 Rod lens 211 Laser processing device 213a to 215b Branch

optical system

225a, 225b, 235a, 235b, 245a, 245b

Optical lens

226a, 226b, 236a, 236b, 246a, 246b Optical fiber

Claims

A beam shaper that shapes the intensity distribution of the laser light emitted from the laser oscillator almost uniformly;
A lens for condensing the laser light emitted from the beam shaper;
A laser processing apparatus comprising: a first optical fiber that receives the laser beam condensed by the lens and transmits the incident laser beam to a processing optical system.
The beam shaper is constituted by a second optical fiber,
When the core diameter of the first optical fiber is φ1, the numerical aperture is NA1, the core diameter of the second optical fiber is φ2, and the numerical aperture is NA2,
φ2> φ1
NA2 ≦ NA1 × (φ1 / φ2)
The laser processing apparatus according to claim 1, wherein:
2. The laser processing apparatus according to claim 1, wherein the beam shaper is configured by a second optical fiber in which a rod lens is fused to an end surface on a laser beam incident side.
The laser processing apparatus according to claim 2 or 3, wherein a cross section of a core of the first optical fiber and the second optical fiber is rectangular.