JPH11320162A - Laser light branching device and laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laser light branching device for branching a laser light in terms of time and space without deteriorating the strength of a pulse peak by a simple structure of a single driving part even if the branching number is increased. SOLUTION: An output laser light 4 is divided into pulse lasers 4a-4c per pulse on an xy plane by means of a galvano mirror 1 for continuously carrying out the rotational movement, incident on a cylindrical fθ lens 2 having a curvature on the xy plane, and reflected by flat reflection mirrors 3a-3c disposed on a straight line on a focal face xz plane of the lens 2. The flat reflection mirrors 3a-3c are inclined from the xz plane at a slightly different angle, and the reflected laser lights are deflected in a z direction slightly and incident on the cylindrical fθ lens 2 again. Laser lights 5a-5c transmitted through the lens are deflected in a z direction slightly, reflected by the galvano mirror 1 again, and branched per pulse as branching laser lights 6a-6c in terms of time and space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch optical system for transmitting energy of laser light used for laser processing and the like, and a laser processing apparatus.

[0002]

2. Description of the Related Art In order to improve the efficiency in laser processing, a laser beam is branched on a plurality of optical axes, a processing unit is arranged on each of the branched optical axes, and the laser light is applied to each processing unit. A method of transmitting energy is effective.

Conventionally, a branch optical system used in a laser processing apparatus is known from Japanese Patent Application Laid-Open No. 61-17392. FIG. 4 shows a system configuration of a branch optical system used in a conventional laser processing apparatus. In FIG. 4, reference numeral 9 denotes a laser oscillator, 10a, 10b, and 10c denote partially transmitting mirrors of a beam splitter, and 11 denotes a reflecting mirror. In such an optical system, a method of equally dividing the output laser light into four is as follows.

In order to divide the output laser beam into four equal parts, the transmittance ra of the beam splitter 10a is 75%, the transmittance rb of the beam splitter 10b is 66.7%, and the transmittance rc of the beam splitter 10c is 50%. Laser light, 6a, 6b, 6
c and 6d are 0.25 for the branched laser light 6a and 0.33 for the branched laser light 6b with respect to the output light 4 from the laser oscillator.
3 × 0.75 = 0.25, the split laser beam 6c is 0.5 ×
0.5 = 0.25, the branched laser beam 6d is (1-0.25
× 3) = 0.25, and the branched laser light used for processing is reduced to ４ of the output laser light.

As another conventional example, Japanese Patent Application Laid-Open No.
A branch optical system of a laser processing apparatus described in Japanese Patent No. 26186 is known. FIG. 5A is a schematic diagram of a branch optical system used in the laser processing apparatus, and is shown as a configuration example in which a laser beam is branched into three. 12a in FIG.
Reference numeral 12b denotes a rotating chopper mirror which is a main component of the branch optical system, and includes a window 16a and a reflection mirror 17a as shown in FIG. 5B. Reference numerals 13a and 13b denote a rotation drive unit of the rotary chopper mirror, 14 denotes an oscillation control device of the laser oscillator 9, and 15 denotes a rotation control device of the rotation drive unit.

In the optical system thus configured, the rotating chopper mirrors 12a and 12b are
The laser oscillator 9 rotates in synchronization with the rotation of the rotating chopper mirror by the oscillation controller 14.
Pulse oscillation. As a result, the rotating chopper mirror 1
The pulse laser light reflected by the reflection mirror portion 17a of FIG.
a through the window 16a and the rotating chopper mirror 12b
The pulse laser light reflected by the reflection mirror unit 17b becomes the branched laser light 6b, and the rotary chopper mirror 12a,
The pulse laser light that has passed through the windows 16a and 16b of the 12b and is reflected by the reflecting mirror 11 becomes a branched laser light 6c.
It is configured to temporally branch in the order of 6a → 6b → 6c → 6a → 6b →... For each pulse.

In the branching optical system using the beam splitter shown in FIG. 4, since the laser light is simply split, the intensity of the split laser light becomes weak in proportion to the number of splits. For example, when branching a pulsed laser beam, the pulse peak intensity becomes 1 /
It decreases to 2, 1/3, and 1/4, and a large pulse peak intensity is required for laser processing. On the other hand, since a plurality of beam splitters, which are transmission optical elements, are used, the transmission mirror of the half mirror portion 10a close to the laser oscillator needs to withstand laser light having a pulse peak intensity that is several times the number of branches. There is a contradictory problem that it becomes difficult to use a laser beam having a high pulse peak intensity in consideration of damage.

On the other hand, in the branching optical system using the rotating chopper mirror shown in FIG. 5, the pulse peak does not change because the laser light is divided in time, but a plurality of rotating chopper mirrors must be rotated synchronously. As the number of branches increases, the number of driving units increases, control becomes complicated, and requirements for synchronization accuracy and mechanical accuracy of the rotating chopper mirror become strict. Further, when the pulse repetition is fast, it is necessary to operate the rotating chopper mirror at high speed and with high accuracy.

[0009]

In this conventional laser processing apparatus, it is necessary to suppress an optical element or a pulse peak intensity that can withstand a laser beam having a pulse peak intensity, or to increase the number of driving parts when the number of branches increases. There are issues such as the need to make it work.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a low-cost and high-performance laser beam branching device using a simple branching optical system composed of a single drive unit and a configuration of a control device. The purpose is to provide.

[0011]

According to the present invention, there is provided a light deflecting element for deflecting laser light in a predetermined direction, a reflecting optical element for reflecting the deflected laser light, and a focal position being the same. First and second arranged to be
With a laser beam branching device having a focusing optical element,
The laser beam is configured to branch in a plurality of directions.

Thus, with a simple configuration having a single drive unit, it is possible to branch a laser beam at a high speed in terms of time and to a large number of spatial positions. Further, a high-quality branched laser light having good directional stability of the branched laser light, which affects the accuracy of the processed component, and a high peak pulse intensity, is obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, an optical deflecting element for deflecting laser light in a predetermined direction and a light deflecting element which is perpendicular to a plane formed by the optical axis of the deflected laser light are different from each other. A laser beam splitting device comprising a plurality of reflecting optical elements inclined at an angle and first and second condensing optical elements arranged so as to have the same focal position. High-speed branching in a plurality of directions is possible, and the directional stability of the branched laser light is good, and it has the effect of high quality.

According to a second aspect of the present invention, there is provided a laser having a galvanomirror as an optical deflecting element and a cylindrical lens serving also as the first and second condensing optical elements, and deflected as a reflecting optical element. 2. The laser beam branching device according to claim 1, further comprising a plurality of plane mirrors arranged on one straight line inclined at different angles perpendicularly to a plane formed by the optical axis of the light. In addition, high-speed branching in a plurality of directions is possible, and the directional stability of the branched laser light is good, and high quality is achieved.

According to a third aspect of the present invention, the first condensing optical element is a cylindrical lens, and the reflecting optical element is arranged on a circumference around the rotation axis of the galvanomirror. 3. The laser beam splitting device according to claim 2, wherein the laser beam splitting device is a cylindrical concave mirror that also serves as an optical element. , And has the effect of achieving high quality.

According to a fourth aspect of the present invention, in the laser light branching device according to any one of the first to third aspects, the laser light to be supplied is a time-division pulsed laser light. This has the effect that a temporally high-speed branch can be made in the direction.

According to a fifth aspect of the present invention, in the laser beam branching device according to the fourth aspect, the pulse laser light is supplied to a plurality of reflective optical elements in synchronization with the deflection of the optical deflecting element. It has an effect that high-speed branching can be performed.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a diagram showing the principle of operation of a laser beam splitting device according to Embodiment 1 of the present invention. In FIG. 1, a galvanomirror 1 continuously rotates and outputs laser beam 4 in xy. The output laser beam 4 is distributed in a plane, and is divided into pulse laser beams 4a, 4b, and 4c for each pulse. The pulse laser beams 4a, 4b, 4c are
The plane reflecting mirrors 3a, 3b, which are incident on the cylindrical fθ lens 2 having a curvature in the xy plane and are arranged on one straight line on the focal plane xz plane of the cylindrical fθ lens 2,
It is reflected at 3c.

Here, the plane reflecting mirrors 3a, 3b and 3c are arranged at slightly different angles inclining from the xz plane. The laser light reflected by the plane reflecting mirrors 3a, 3b, 3c is deflected in the z direction slightly differently in accordance with the inclination of each plane reflecting mirror, and reenters the cylindrical fθ lens 2. The laser beams 5a, 5b, and 5c transmitted through the cylindrical fθ lens 2 are slightly deflected in the z direction, and are reflected again by the galvanometer mirror 1.

FIG. 2 shows an example of a temporal change in the intensity of the output laser beam 4 and a temporal change in the intensity of the branched laser beams 6a, 6b and 6c. 1 of output laser light 4
Focusing on the pulse, the pulsed laser beam 4a distributed by the galvanomirror 1 rotating continuously passes through the cylindrical fθ lens 2 and enters the plane reflecting mirror 3a. The pulse laser beam 4a is scanned in the x direction on the plane reflecting mirror 3a within a finite pulse time, but is reflected and re-transmitted through the cylindrical fθ lens 2, so that it has the same optical path as 4a in the xy plane. 5a, reflected by the galvanomirror 1 and split by the branched laser light 6a.
Becomes The branched laser light 6a is slightly deflected in the z direction with respect to the optical path of the output laser 4 because the plane reflecting mirror 3a is arranged slightly inclined with respect to the xz plane about the x-axis direction.

Similarly, the pulse laser beams 4b and 4c become the branch laser beams 6b and 6c. Here, the plane reflecting mirror 3a,
Since the inclination angles of 3b and 3c are different from each other, the optical paths of the branched laser beams 6a, 6b and 6c are the same in the xy plane, but are different in the z direction. Thus, the output laser light 4 is z
Laser beam 6 for each pulse in an optical path different only in the direction
a, 6b, and 6c.

The present invention can be applied to a modification or a modification of the above embodiment without departing from the gist of the invention. For example, in the above embodiment, an example of three branches using three plane reflecting mirrors has been described, but it is easy to increase the number of branches according to the purpose.

In this embodiment, the laser beam branching device has been described. However, a laser beam processing device can be easily realized by applying to a conventional laser beam processing device.

(Embodiment 2) FIG. 3 is a plan view of a laser beam splitting device according to Embodiment 2 of the present invention, and FIG.
, The galvanomirror 1 continuously rotates,
The output laser light 4 transmitted through the cylindrical lens 8 having the focal length f 'is distributed in the xy plane, and the output laser light 4 is distributed into pulse laser lights 4a, 4b, and 4c for each pulse. The sorted pulse laser beams 4a and 4a
b and 4c are reflected by cylindrical concave mirrors 7a, 7b and 7c having a curvature R in the xy plane. Here, the cylindrical concave mirrors 7a, 7b, 7c are arranged on a concentric circle at a distance R from the rotation center of the galvanometer mirror 1, and xy
It is arranged at a slightly different angle from the vertical direction with respect to the plane.

Further, the cylindrical lens 8 is arranged so that the focal position is located at a distance R / 2 from the rotation center of the galvanometer mirror 1. Cylindrical concave mirror 7
The pulsed laser beams reflected by a, 7b, and 7c are reflected by the respective cylindrical concave mirrors in accordance with the inclinations of the respective cylindrical concave mirrors as shown in FIG.
The light is slightly deflected in the z-direction as shown in FIG.

Focusing on one pulse of the output laser light 4, the pulsed laser light 4a incident on the cylindrical lens 8 as parallel light is distributed by the galvanomirror 1 which continuously rotates, and Is focused at a position of a distance R / 2 from the center of rotation of, and enters the cylindrical concave mirror 7a while diverging. Here, since the focal length of the cylindrical concave mirror 7a having the curvature R is f = R / 2, the cylindrical concave mirror 7a
The laser light 5a reflected by the light becomes parallel light again. The pulsed laser beam 4a is scanned on the cylindrical concave mirror 7a within a finite pulse time. However, since the cylindrical concave mirror 7a having a radius of curvature R is arranged at a distance R from the rotation center of the galvanometer mirror 1, the laser beam 4a and 5
The optical axis of a is the same in the xy plane. The laser beam 5a is reflected by the galvanomirror 1 and becomes a branched laser beam 6a. The branched laser light 6a has an elliptical shape as shown in FIG. The diameter d2 of the branched laser light 6a in the minor axis direction has a relationship of d2 / d1 = f / f 'with respect to the diameter d1 of the pulsed laser light 4a. Since the cylindrical concave mirror 7a is arranged slightly inclined from the vertical direction with respect to the xy plane, the branched laser light 6a
Deflected in the direction.

Similarly, the pulse laser beams 4b and 4c become the branch laser beams 6b and 6c. Here, since the inclination angles of the cylindrical concave mirrors 7a, 7b, and 7c are different from each other, the optical axes of the branched laser beams 6a, 6b, and 6c are the same in the xy plane, but as shown in FIG. Different. As described above, the output laser light 4 is divided into pulses having different times on different optical paths only in the z direction, and the branched laser light 6
a, 6b, and 6c.

The present invention can be applied to a modification or a modification of the above embodiment without departing from the gist of the invention. For example, in the above embodiment, an example of three branches using three cylindrical concave mirrors has been described, but it is easy to increase the number of branches according to the purpose.

By arranging a spherical lens at the position of the cylindrical lens 8 and arranging the cylindrical lens so as to have a confocal point in front of the spherical lens, the branched laser light can be easily shaped into a circle.

[0030]

As described above, according to the present invention, even if the number of branches is increased, the laser beam can be transmitted at a high speed in time and space with a simple configuration consisting of a single drive unit without increasing the number of drive units. Laser beam branching device that branches to a large number of locations is possible, and the directional stability of the branched laser beam, which affects the accuracy of the machined part, is good. Thus, an advantageous effect of obtaining a high-quality branched laser beam having a high peak pulse intensity can be obtained.

[Brief description of the drawings]

FIG. 1 is an operation principle diagram of a laser beam splitting device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a temporal intensity change of an output laser beam and a temporal intensity change of each branched laser beam.

3A is a plan view of a laser beam splitting device according to a second embodiment of the present invention. FIG. 3B is a side view of the laser beam splitting device according to the second embodiment of the present invention.

FIG. 4 is a schematic view of a beam splitter branch optical system used in a conventional laser processing apparatus.

5A is a schematic view of a rotary chopper mirror branch optical system used in a conventional laser processing apparatus. FIG. 5B is a plan view of a rotary chopper mirror part of a branch optical system used in a conventional laser processing apparatus.

[Explanation of symbols]

 Reference Signs List 1 Galvano mirror 2 Cylindrical fθ lens 3a Planar reflecting mirror 1 3b Planar reflecting mirror 2 3c Planar reflecting mirror 3 4 Output laser light 4a Pulse laser light 1 4b Pulse laser light 2 4c Pulse laser light 3 5a Laser reflected by the plane reflecting mirror Light 1 5b Laser light 2 5c reflected by a plane reflecting mirror Laser light 36 6 reflected by a plane reflecting mirror 6a Branched laser light 1 6b Branched laser light 2 6c Branched laser light 3 6d Branched laser light 4 7a Cylindrical concave mirror 1 7b Cylindrical Concave mirror 2 7c Cylindrical concave mirror 3 8 Cylindrical lens 9 Laser oscillator

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H01S 3/00 H01S 3/00 B

Claims (6)

[Claims] An optical deflecting element for deflecting the laser light in a predetermined direction; a plurality of reflective optical elements each inclined at a different angle perpendicular to a plane formed by the optical axis of the deflected laser light;
A laser beam splitting device comprising: first and second condensing optical elements arranged so as to have the same focal position. 2. A plane defined by a galvanomirror, which is a light deflecting element, and a cylindrical lens, which also serves as the first and second condensing optical elements, and formed by an optical axis of laser light deflected as a reflecting optical element. 2. A laser beam splitting device according to claim 1, wherein a plurality of plane mirrors are provided which are arranged on one straight line at an angle different from each other at right angles to the mirror. 3. The first condensing optical element is a cylindrical lens, and a cylindrical concave mirror serving also as a second condensing optical element disposed on a circumference centered on a rotation axis of a galvanomirror of a reflection optical element. 3. The laser beam splitting device according to claim 2, wherein 4. The laser beam splitting device according to claim 1, wherein the laser beam to be supplied is a time-division pulsed laser beam. 5. The laser beam splitter according to claim 4, wherein the pulse laser beam is supplied to a plurality of reflection optical elements in synchronization with the deflection of the light deflection element. 6. A laser processing apparatus using the laser beam branching device according to claim 1.