JP2003039188A - Laser beam machining method and laser beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining method capable of machining with a narrow pitch. SOLUTION: Each split beam LB1-LB4 emitted from the terminal of each optical fiber 5a-5d is made incident with an angle through objective lenses 6a-6d against an incident face of beam refraction elements 7a-7d, passes through inside the each refraction element 7a-7d while converging, and goes out in a state that its optical axis is parallel shifted from the emitting face parallel with the incident face toward the inside. As shown in figure 2, each of the split beam LB1-LB4 passing through each refraction element 7a-7d and emitted to a work W is parallel with each other with respect to each of its optical axis, thereby the distance D2 between the optical axes (equivalent to a machining pitch) becomes smaller than the distance of disposition of the emitting parts of the optical fibers 5a-5d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method and a laser processing apparatus for simultaneously irradiating a work with two or more laser beams to perform processing such as drilling, grooving, cutting, and welding.

[0002]

2. Description of the Related Art A laser processing apparatus capable of simultaneously performing two or more processings on a work piece is of a type in which laser beams emitted from a plurality of laser oscillators are guided to the work piece through an optical system. And a type in which a laser beam emitted from one laser oscillator is divided into a plurality of laser beams and each of the divided laser beams is guided to a workpiece through an optical system (Japanese Patent Laid-Open No. 2000-263).
268 and Japanese Patent Laid-Open No. 11-254170.

[0003]

By the way, the processing pitch (center-to-center distance between processing points) when the above-described laser processing apparatus simultaneously performs two or more processings on a workpiece is limited by the irradiation optical system. That is, in the case of an optical system that irradiates a workpiece with a laser beam via an objective (imaging) lens, the processing pitch is made smaller than the distance between the optical axes of the objective lenses having a predetermined size and array structure. In addition, in the case of an optical system in which a laser beam is directly radiated to a workpiece from an optical fiber, the processing pitch cannot be made smaller than the optical axis distance of an optical fiber having a predetermined diameter and array structure.

If the laser beam is emitted while being inclined so that its optical axis has an angle with respect to the normal to the surface to be illuminated, it is possible to reduce the processing pitch even with the above-mentioned illumination optical system. Since the irradiation shape of the obliquely irradiated laser beam is distorted, it becomes impossible to uniformly perform processing by each irradiation laser beam.

The present invention was made in view of the above circumstances, and an object thereof is to provide a laser processing method capable of processing at a narrow pitch and a laser processing apparatus suitable for carrying out this method. Especially.

[0006]

In order to achieve the above object, a laser processing method according to the present invention is a laser processing method in which a workpiece is simultaneously irradiated with two or more laser beams for processing. The beam refracting means provided between the laser beam irradiation optical system and the workpiece so as to correspond to each laser beam makes the distance between the optical axes of the incident laser beam smaller than the arrangement interval of the irradiation optical system. In addition, the light is refracted so that the optical axes thereof are parallel to each other and emitted, and the emitted laser beam is applied to the workpiece. According to this processing method, each laser beam emitted from the irradiation optical system is incident on the beam refracting means so that the distance between the optical axes of the incident laser beams becomes smaller than the arrangement interval of the irradiation optical system, and , Refracted so that their optical axes are parallel to each other,
It is possible to irradiate the workpiece with this emitted laser beam.

Further, the laser processing apparatus according to the present invention is
A laser processing device for simultaneously irradiating a workpiece with two or more laser beams for processing, wherein the distance between the optical axes of the incident laser beams is between the irradiation optical system of each laser beam and the workpiece. The beam refraction means capable of refracting and emitting so as to be smaller than the arrangement interval of the irradiation optical system and having their optical axes parallel to each other is provided corresponding to each laser beam. To do. According to this processing apparatus, the above processing method can be carried out accurately and stably.

The above and other objects, constitutional features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows the configuration of a laser processing apparatus according to a first embodiment of the present invention. In the figure, reference numeral 1 is a laser oscillator, 2 is a mirror, 3 is a beam splitter, 4a to 4d are condenser lenses, 5a to 5d are optical fibers, 6a to 6d are objective (imaging) lenses, and 7a to 7d are beams. Refraction element, LB is laser beam, LB1 to LB
Reference numeral 4 is a split beam, and W is a workpiece. The laser processing apparatus shown in FIG. 1 includes optical elements other than those shown in the figure, such as a beam expander for expanding the beam, a collimator for expanding and collimating the beam, and an aperture for shaping the beam. A mask or the like for cutting an unnecessary portion from the beam may be used as necessary.

The laser oscillator 1 is a YAG laser or C
The laser beam LB is composed of a known laser oscillator such as an O ₂ laser or an excimer laser, and can emit a laser beam LB having a sufficient output for performing processing such as punching, grooving, cutting, and welding on the workpiece W.

The beam splitter 3 divides the laser beam LB emitted from the laser oscillator 1 and reflected by the mirror 2 into four beams.
The beam splitter is divided into three beam splitters 3a to 3a.
c and nine mirrors 3d to 3l.

The laser beam LB emitted from the laser oscillator 1 and reflected by the mirror 2 is first split into two by the first beam splitter 3 a of the beam splitter 3. 1
One of the split beams split by the second beam splitter 3a is reflected by the mirror 3d and then split into two by the second beam splitter 3b, and one split beam is reflected by the mirror 3e to become the first split beam LB1. The other split beam is reflected by the mirrors 3f and 3g to become the second split beam LB2. The other split beam split by the first beam splitter 3a is reflected by the mirrors 3h and 3i and then split into two by the third beam splitter 3c, and one split beam is reflected by the mirror 3j and is split by the third beam splitter 3c. Divided beam LB3 and the other divided beam is reflected by mirrors 3k and 3l to become a fourth divided beam LB2.

In this beam splitter 3, the beam splitters 3a to 3c and the mirrors 3d to 3l are arranged so that the optical path lengths of the first to fourth split beams LB1 to LB4 are all equal. There is no variation in the quality of LB1 to LB4. Of course, instead of the beam splitter 3 shown in FIG. 1, a beam splitter having another configuration capable of dividing into 4 may be used.

The split beams LB1 to LB4 emitted from the beam splitter 3 are respectively incident on the optical fibers 5a to 5d of the same length through the condenser lenses 4a to 4d of the same standard, which are arranged corresponding to the split beams LB1 to LB4, respectively. 5a-5
Propagate through the core of d.

Since the output portions of the optical fibers 5a to 5d are arranged so that their optical axes are parallel to each other and are aligned in a line at equal intervals, the split beams LB1 to LB4 propagated through the optical fibers 5a to 5d are the respective optical fibers. The light beams are emitted from the ends of 5a to 5d so that their optical axes are parallel to each other and are arranged in a line at equal intervals, and beam refraction is performed through objective lenses 6a to 6d of the same standard arranged corresponding to the ends of the optical fibers 5a to 5d. The light enters the elements 7a to 7d, respectively.

The split beams LB1 to LB4 incident on the beam refracting elements 7a to 7d are respectively divided into the beam refracting elements 7a to 7d.
A predetermined beam refracting action is caused by 7d so that the optical axes of the beam refracting elements 7a to 7d are parallel to each other and are arranged in a line at equal intervals smaller than the arrangement intervals of the emitting portions of the optical fibers 5a to 5d. To the workpiece W
The workpiece W is simultaneously irradiated so as to form an image on the surface to be irradiated with or in the vicinity thereof, and processing such as drilling, grooving, cutting and welding is performed.

Below, the configurations and functions of the beam refracting elements 7a to 7d will be described in detail with reference to FIGS.

The four beam refracting elements 7a to 7d are made of an optical material such as borosilicate crown glass, synthetic quartz glass, silicon and zinc selenium, and each split beam LB1.
It is transparent to the wavelength of LB4 and has a refractive index larger than that of air. Each of the beam refracting elements 7a to 7d is preferably made of the same optical material, and is attached to a holder (not shown) so that the inclination thereof can be changed.

Each of the beam refracting elements 7a to 7d is shown in FIG.
As shown in (A) and (B), the incident surface IF and the exit surface OF
And a parallel prismatic shape or a cylindrical shape (not shown). In FIG. 2, the two beam refracting elements 7a and 7b on the right side and the two beam refracting elements 7c and 7d on the left side are symmetrically inclined, and the inclinations of the two beam refracting elements 7a and 7d on both sides are the center two beam refracting elements 7b. And 7c.

Each of the beam refracting elements 7a to 7d imparts a predetermined refracting action to each of the divided beams LB1 to LB4 in accordance with its inclination. This refraction effect is, as shown in FIG.
Parallel plate ID1 with transparent directional laser beam
When obliquely incident on one surface, the optical axis CAb of the laser beam LBb emitted from the other surface is displaced parallel to the optical axis CAa of the incident laser beam LBa, and the deviation amount DE is changed in accordance with the change of the incident angle. Based on the principle of increasing or decreasing.

That is, as shown in FIG. 2, the split beams LB1 to LB4 emitted from the ends of the respective optical fibers 5a.
Is the beam refraction element 7a through the objective lenses 6a to 6d.
Incident at an angle to each of the incident surfaces of ~ 7d,
The light passes through each of the beam refracting elements 7a to 7d while being condensed, and is emitted from an emission surface parallel to the incident surface with its optical axis shifted in parallel to the inside. As can be seen from FIG. 2, the split beams LB1 to LB4 that pass through the beam refracting elements 7a to 7d and are irradiated onto the workpiece W have their optical axes parallel to each other, and the optical axis distance D2 (processing) The pitch is smaller than the arrangement interval (distance between optical axes D1) of the emitting portions of the optical fibers 5a to 5d.

The size of each of the beam refracting elements 7a to 7d is determined to some extent in relation to the focal length defined by the objective lenses 6a to 6d. When it can be used as 7d, the distance D2 between the optical axes can be considerably reduced by changing the incident angle.

Further, the inclination of the two beam refracting elements 7a and 7d on both sides is such that the two beam refracting elements 7b and 7c at the center are inclined.
Is larger than the tilt of the objective lens 6a, if the two beam refracting elements 7a and 7d on both sides have the same size as the central two beam refracting elements 7b and 7c.
And 6d, the optical path lengths of the first and fourth split beams LB1 and LB4 until they reach the object W to be processed are the second optical path lengths from the objective lenses 6b and 6c until they reach the object W to be processed. It becomes shorter than the optical path length of the third split beams LB2 and LB3, and the image formation position is deviated.

In order to solve this problem, the lengths of the two beam refracting elements 7a and 7d on both sides are made shorter than those of the two central beam refracting elements 7b and 7c, so that each of the objective lenses 6a ...
The optical path lengths of the divided beams LB1 to LB4 emitted from 6d and reaching the workpiece W are matched with the focal lengths defined by the objective lenses 6a to 6d.
Of course, the adjustment of the optical path length may be performed by individually changing the positions of the objective lenses 6a to 6d, or by adjusting the beam refracting elements 7 respectively.
It is also possible to use a to 7d having different refractive indexes.

As described above, according to the laser processing method and the laser processing apparatus described above, when the workpiece W is simultaneously irradiated with the four laser beams LB1 to LB4, the processing pitch is limited by the irradiation optical system. Even if the workpiece W is received, it is possible to appropriately and simultaneously perform four processes on the workpiece W with a smaller processing pitch.

Further, by changing the inclination of each of the beam refracting elements 7a to 7d, it is possible to finely adjust the position of the portion to be processed by each of the divided beams LB1 to LB4, or to make the processing pitch different from each other.

In the above description, the optical fibers 5a ...
Although the output portions of 5d are shown in such a manner that their optical axes are parallel to each other and are arranged in a line at equal intervals, the optical fibers 5a to 5d are shown.
Even if the beams are arranged in a two-dimensional array, each beam refraction element 7
If the array of a to 7d is a two-dimensional array adapted to the array of the optical fibers 5a to 5d, the same function and effect as described above can be obtained. In addition, even when the distances between the optical axes of the emission portions of the optical fibers 5a to 5d are not equal, each beam refraction element 7a
By appropriately adjusting the inclination of 7d, the same effect as described above can be obtained.

In the above description, the laser beam LB emitted from one laser oscillator 1 is divided into four, and the four divided beams LB1 to LB4 are guided to the four beam refracting elements 7a to 7d. However, even if a configuration is adopted in which each of the laser beams emitted from the four laser oscillators is guided to the four beam refracting elements 7a to 7d via the optical system, the same operational effect can be obtained.

Further, in the above description, the workpiece W is
Although shown is one in which two laser beams LB1 to LB4 are simultaneously irradiated, even when two or three laser beams are simultaneously irradiated to the workpiece or when five or more laser beams are simultaneously irradiated to the workpiece. By preparing a beam refraction element according to the number of irradiation laser beams and disposing it between the irradiation optical system and the object to be processed, the same effect as described above can be obtained.

Further, in the above description, the beam refracting elements 7a to 7d are attached to the holders (not shown) so that the respective inclinations can be changed, but the inclination angles can be fixed and used. In the case, as shown in FIG. 5, the beam refraction element 8 having an integral structure having four beam refraction regions 8a to 8d may be used.

[Second Embodiment] FIG. 6 is an enlarged view of a main part of a laser processing apparatus according to a second embodiment of the present invention. In the figure, reference numerals 5a to 5d are optical fibers, 6a to 6d are objective (imaging) lenses, 9a to 9d are beam refracting elements, LB is a laser beam, LB1 to LB4 are split beams, and W is a workpiece.

The second embodiment differs from the first embodiment in the configuration of the beam refracting elements 9a to 9d and the directions of the exit portions of the optical fibers 5a and 5d. Other configurations are first
Since it is the same as that shown in the embodiment, the same reference numerals are used and the description thereof is omitted.

The four beam refracting elements 9a to 9d are made of an optical material such as borosilicate crown glass, synthetic quartz glass, silicon and zinc selenium, and each split beam LB1.
It is transparent to the wavelength of LB4 and has a refractive index larger than that of air. Each of the beam refracting elements 9a to 9d is preferably made of the same optical material, and is attached to a holder (not shown) so that the inclination thereof can be changed.

Of the four beam refracting elements 9a-9d,
As shown in FIG. 7A, the two beam refracting elements 9a and 9d on both sides have a prismatic shape in which the entrance surface IF and the exit surface OF are not parallel to each other or a cylindrical shape (not shown). And 9c are incident planes I as shown in FIG.
F and the exit surface OF are parallel prismatic shapes or columnar shapes (not shown). In FIG. 6, the two beam refracting elements 9a and 9b on the right side and the two beam refracting elements 9c and 9d on the left side are inclined symmetrically, and the inclinations of the two beam refracting elements 9a and 9d on both sides are the center two beam refracting elements 9b. And 9c.

On the other hand, of the four optical fibers 5a to 5d, the emission portions of the two optical fibers 5a and 5d on both sides are inclined similarly to the two beam refracting elements 9a and 9d on both sides, and the optical axes of the respective emission portions are the same. Beam refraction element 9a
And 9d are perpendicular to the plane of incidence. The positional relationship between the output portions of the two central optical fibers 5b and 5c and the beam refracting elements 9b and 9c is the same as that of the first embodiment.

Each of the beam refracting elements 9a to 9d imparts a predetermined refracting action to each of the divided beams LB1 to LB4 in accordance with its inclination. Two beam refracting elements 9a and 9 on both sides
As shown in FIG. 8, when the laser beam having directivity is perpendicularly incident on one surface of the transparent non-parallel plate ID2, the optical axis of the laser beam LBb emitted from the other surface is d. It is based on the principle of refraction at an angle with respect to the optical axis of the incident laser beam LBa. Further, the refracting action of the two central beam refracting elements 9b and 9c is similar to that shown in FIG. 4, when a laser beam having directivity is obliquely incident on one surface of the transparent parallel plate ID1, the other The optical axis CAb of the laser beam LBb emitted from the surface is shifted parallel to the optical axis CAa of the incident laser beam LBa, and the shift amount DE is increased or decreased according to the change of the incident angle.

That is, as shown in FIG. 6, the split beams LB1 and LB4 emitted from the ends of the two optical fibers 5a and 5d on both sides are perpendicular to the incident surfaces of the beam refracting elements 7a to 7d through the objective lenses 6a and 6d. To the beam refracting elements 9a and 9d while converging, and exits from the exit surface that is not parallel to the entrance surface with its optical axis refracted outward. Also, each split beam L emitted from the ends of the two central optical fibers 5b and 5c
B2 and LB3 are incident on the incident surfaces of the beam refracting elements 9b and 9c at angles through the objective lenses 6b and 6c, pass through the respective beam refracting elements 9b and 9c while being condensed, and are parallel to the incident surfaces. The light is emitted from the emission surface with its optical axis shifted in parallel to the inside. As can be seen from FIG. 6, the split beams LB1 to LB4 which pass through the beam refracting elements 9a to 9d and are applied to the workpiece W are divided.
Have mutually parallel optical axes, and the distance D2 between the optical axes (corresponding to the processing pitch) is smaller than the arrangement interval of the emitting portions of the optical fibers 5a to 5d.

The size of each beam refracting element 9a to 9d is determined to some extent in relation to the focal length defined by the objective lenses 9a to 9d. When it can be used as 9d, the distance D2 between the optical axes can be considerably reduced by changing the incident angle.

Further, the inclinations of the two beam refracting elements 9a and 9d on both sides are such that the two beam refracting elements 9b and 9c at the center are inclined.
Since the inclination is larger than that of the objective lens 6a, the two beam refracting elements 9a and 9d on both sides of the objective lens 6a are similar in size to the central two beam refracting elements 9b and 9c.
And 6d, the optical path lengths of the first and fourth split beams LB1 and LB4 until they reach the object W to be processed are the second optical path lengths from the objective lenses 6b and 6c until they reach the object W to be processed. It becomes shorter than the optical path length of the third split beams LB2 and LB3, and the image formation position is deviated.

In order to solve this problem, the lengths of the two beam refracting elements 9a and 9d on both sides are made shorter than those of the two central beam refracting elements 9b and 9c, so that each objective lens 6a.about.
The optical path lengths of the divided beams LB1 to LB4 emitted from 6d and reaching the workpiece W are matched with the focal lengths defined by the objective lenses 6a to 6d.
Of course, the adjustment of the optical path length is performed by individually changing the positions of the objective lenses 6a to 6d, or by adjusting the beam refracting elements 9a and 9b.
It is also possible to use a to 9d having different refractive indexes.

As described above, according to the laser processing method and the laser processing apparatus described above, when the workpiece W is simultaneously irradiated with the four laser beams LB1 to LB4, the processing pitch is limited by the irradiation optical system. Even if the workpiece W is received, it is possible to appropriately and simultaneously perform four processes on the workpiece W with a smaller processing pitch.

Further, by changing the inclination of each of the beam refracting elements 9a to 9d, it is possible to finely adjust the position of the portion to be processed by each of the divided beams LB1 to LB4, or to make the processing pitch different from each other.

In the above description, the optical fibers 5a ...
Although the output portions of 5d are arranged in a line, even if the output portions of the optical fibers 5a to 5d are arranged in a two-dimensional array, the arrangement of the beam refracting elements 9a to 9d is changed to the arrangement of the optical fibers 5a to 5d. If the two-dimensional array is adapted, the same effect as the above can be obtained.

In the above description, the laser beam LB emitted from one laser oscillator 1 is divided into four, and the four divided beams LB1 to LB4 are guided to the four beam refracting elements 9a to 9d. However, even if a configuration is adopted in which the laser beams emitted from the four laser oscillators are guided to the four beam refracting elements 9a to 9d via the optical system, the same operational effects as described above can be obtained.

Further, in the above description, the workpiece W is 4
Irradiation with one laser beam LB1 to LB4 is shown, but irradiation is performed even when two or three laser beams are applied to the work piece or when five or more laser beams are applied to the work piece. By preparing beam refracting elements according to the number of laser beams and arranging them between the irradiation optical system and the workpiece, the same operational effects as described above can be obtained.

Further, in the above description, the beam refracting elements 9a to 9d are attached to the holders (not shown) so that the respective inclinations can be changed, but the inclination angles can be fixed and used. In the case, as shown in FIG. 9, the beam refraction element 10 having an integral structure having four beam refraction regions 10a to 10d may be used.

As described above, in the first and second embodiments, the beam refracting elements 7a to 7d, 8, 9a to 9d, 10 are used.
Although the solid-state type made of an optical material is shown as, the semi-solid-state type or the liquid-phase type may be used as the beam refraction element.

10 (A) and 10 (B) show an example thereof, and the beam refraction element 11 is a flexible container 11a.
The inside of the container 11a is filled with the liquid 11b.
The liquid 11b is transparent to the wavelength of the incident laser beam LBa and has a refractive index larger than that of air.

The beam refraction element 11 can change its shape by deforming the container 11.
The shape shown in FIG. 10 (A) in which the incident surface and the exit surface are parallel to each other and the shape shown in FIG. 10 (B) in which the incident surface and the exit surface are not parallel can be appropriately obtained. Similar to the beam refracting element described above, when the beam refracting element 11 has the shape shown in FIG. 10A, the laser beam LB incident at an angle with respect to the incident surface has its optical axis parallel to the exit surface. Emit in the shifted state. In addition, the beam refraction element 11 is shown in FIG.
In the case of the shape shown in (1), the laser beam LB which is incident perpendicularly to the incident surface is emitted from the emitting surface with its optical axis being refracted.

[0050]

As described in detail above, according to the present invention,
Even if the processing pitch is limited by the irradiation optical system when the workpiece is irradiated with two or more laser beams at the same time, the workpiece can be processed with a smaller processing pitch by two or more. It can be done simultaneously and properly.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a laser processing apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the laser processing apparatus shown in FIG.

FIG. 3 is a perspective view of the beam refraction element shown in FIG.

FIG. 4 is an explanatory diagram of a beam refraction action in a beam refraction element.

5 is a diagram showing a modification of the beam refraction element shown in FIG.

FIG. 6 is an enlarged view of a main part of a laser processing apparatus according to a second embodiment of the present invention.

FIG. 7 is a perspective view of the beam refraction element shown in FIG.

FIG. 8 is an explanatory diagram of a beam refraction action in the beam refraction element.

9 is a diagram showing a modification of the beam refraction element shown in FIG.

10 is a view showing a modification of the beam refraction element shown in FIGS. 1, 5, 6 and 9. FIG.

[Explanation of symbols]

1 ... Laser oscillator, 2 ... Mirror, 3 ... Beam splitter,
4a-4d ... Condensing lens, 5a-5d ... Optical fiber, 6
a to 6d ... Objective (imaging) lens, 7a to 7d ... Beam refracting element, LB ... Laser beam, LB1 to LB4 ... Split beam, W ... Work piece, 8 ... Beam refracting element, 8a-8
d ... Beam refraction region, 9a to 9d ... Beam refraction element, 1
0 ... Beam refraction element, 10a-10d ... Beam refraction area, 11 ... Beam refraction element.

Claims (6)

[Claims] 1. A laser processing method in which a workpiece is simultaneously irradiated with two or more laser beams for processing, and the laser beam is applied between the laser beam irradiation optical system and the workpiece. By the beam refraction means provided as, the incident laser beam is refracted and emitted so that the distance between the optical axes thereof is smaller than the arrangement interval of the irradiation optical system, and the optical axes thereof are parallel to each other. A laser processing method is characterized in that the workpiece is irradiated with this emitted laser beam. 2. The beam refraction means comprises a beam refraction member which is transparent to the wavelength of the laser beam and has a refractive index larger than that of air, and whose entrance surface and exit surface are parallel to each other. The laser processing method according to claim 1, wherein the laser light is incident on the incident surface of the refraction member at an angle, and is emitted from an emission surface parallel to the incident surface with its optical axis shifted in parallel. 3. The beam refraction means comprises a beam refraction member which is transparent to the wavelength of the laser beam, has a refractive index larger than that of air, and has an incident surface and an exit surface which are non-parallel to each other. The light is incident such that its optical axis is perpendicular to the incident surface of the beam refraction member, and the light is emitted from an emission surface that is not parallel to the incident surface in a state where the optical axis is refracted. Laser processing method. 4. A laser processing apparatus for performing processing by simultaneously irradiating a work with two or more laser beams, wherein an incident laser beam is provided between an irradiation optical system of each laser beam and the work. Beam refracting means capable of refracting and emitting so as to make the distance between the optical axes smaller than the arrangement interval of the irradiation optical system and to make the optical axes parallel to each other are provided corresponding to each laser beam. A laser processing device characterized by the following. 5. The beam refraction means comprises a beam refraction member which is transparent to the wavelength of the laser beam and has a refractive index larger than that of air, and whose incident surface and emission surface are parallel to each other. The laser processing apparatus according to claim 4, wherein the laser beam is arranged so that the laser beam is incident on the incident surface at an angle. 6. The beam refraction means comprises a beam refraction member which is transparent to the wavelength of the laser beam, has a refractive index higher than that of air, and has an incident surface and an exit surface which are non-parallel to each other. The laser processing apparatus according to claim 4, wherein the member is arranged so that the laser beam is vertically incident on the incident surface thereof.