JPH0836144A - Laser branching device - Google Patents

Abstract

PURPOSE:To accurately match the laser outputs of all branch laser beams or adjust them individually to desired values without using any attenuation plate. CONSTITUTION:On the optical axis of the original YAG laser beam LB0 outputted by a resonance mirror 12, four partially reflective transmission mirrors 14A, 14B, 14G, and 14D are arranged at fixed positions and at certain intervals while having the same tilt angle (e.g. 45 deg.). On the opposite side from the partial reflective transmission mirrors 14A-14D across the optical axis of the original YAG laser light LBO, incidence units 18A-18D are arranged across shutters 16A-16D, and optical fibers 104A-104D are connected to the other end parts of the incidence units 18A-l8D. Through mirror position adjustment by respective mirror position adjusting mechanisms 24, the reflection factors and transmissivity (R, T) of the respective partially reflective transmission mirrors 14A-14D are set and adjusted to desired values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser branching device for simultaneously branching one original laser beam into a plurality of laser beams.

[0002]

2. Description of the Related Art A laser branching device branches a laser beam output from a laser oscillator into a plurality of laser beams and directs the laser beams to different positions, and is used, for example, in multi-position processing of laser welding.

FIG. 6 shows a laser welding multi-position processing system. A plurality of, for example, four emission units 102A to 102D are connected to one laser device main body 100 via optical fibers 104A to 104D, respectively. In the laser device main body 100, the laser light generated by the laser oscillator is branched into four laser lights by the laser branching device, and these four branched laser lights are respectively incident on one end faces of the optical fibers 104A to 104D by the incident unit. To be done. Each branched laser beam transmitted to each emission unit 102A-102D through each optical fiber 104A-104D is condensed and irradiated toward each work W there. According to such multi-position processing, since a plurality of (four in this example) works W can be simultaneously welded by one laser device main body 100, production efficiency can be improved.

FIG. 7 shows the structure of the main part of a conventional laser branching device for performing simultaneous four-branching in the above-described multi-position processing system. This laser branching device includes three partial reflection / transmission mirrors 106 on the optical axis of an original laser beam LB0 output from a laser oscillator (not shown).
A, 106B, 106C and one total reflection mirror 10
6D is arranged in this order with a certain angle, for example 45 °.

The first partial reflection / transmission mirror 106A on which the original laser beam LB0 first enters has a reflectance of about 25%.
A partially reflective mirror having a transmittance of about 75% is used.
As the second partial reflection / transmission mirror 106B, a partial reflection / transmission mirror having a reflectance of about 33% and a transmittance of about 67% is used. As the third partial reflection / transmission mirror 106B, a partial reflection / transmission mirror having a reflectance of about 50% and a transmittance of about 50% is used. As the final total reflection mirror 106D, a total reflection mirror having a reflectance of about 100% and a transmittance of about 0% is used.

When the original laser beam LB0 enters the first partial reflection / transmission mirror 106A, about 25% (about 0.
25 LB0) is reflected, and about the remaining 75% (about 0.7)
5LB0) is transparent.

When the transmitted light (about 0.75LB0) from the first partial reflection / transmission mirror 106A is incident on the second partial reflection / transmission mirror 106B, about 33% (about 0.2%) of the light is transmitted there.
5LB0) is reflected, and the remaining about 67% (about 0.50
LB0) is transparent.

When the transmitted light (about 0.50 LB0) from the second partial reflection / transmission mirror 106B is incident on the third partial reflection / transmission mirror 106C, about 50% (about 0.2%) thereof is there.
5LB0) is reflected, and about the remaining 50% (about 0.25)
LB0) is transparent.

The transmitted light (about 0.25LB0) from the third partial reflection / transmission mirror 106C is incident on the total reflection mirror 106D and is totally reflected there.

In this way, the four mirrors 106A-
Four reflected lights having substantially the same laser output from 106D are respectively taken out as branched laser lights LBA to LBD.

FIG. 8 shows the structure of another conventional laser branching device. In this laser branching device, three partial reflection / transmission mirrors 108A, 108A ', 108C' and three total reflection mirrors 108B, 108C, 108D are used as the original laser beam LB.
It is arranged in a zigzag at right angles to the optical axis of 0 as shown. Each partial reflection / transmission mirror 108A, 1
For 08A 'and 108C', partial reflection mirrors having a reflectance of about 50% and a transmittance of about 50% are used.

In this laser branching device, the original laser beam LB
When 0 first enters the partial reflection / transmission mirror 108A,
Then, about 50% (about 0.50LB0) is reflected and the remaining about 50% (about 0.50LB0) is transmitted.

The reflected light (about 0.50 LB0) from the first partial reflection / transmission mirror 108A is reflected by the partial reflection / transmission mirror 10.
8A ', and about 50% (about 0.25LB0
) Is reflected and the remaining about 50% (about 0.25LB0
) Is transparent. The transmitted light from the partial reflection / transmission mirror 108A 'is incident on the total reflection mirror 108B and is totally reflected there.

The transmitted light (about 0.50 LB0) from the first partial reflection / transmission mirror 108A is incident on the partial reflection / transmission mirror 108C 'through the total reflection mirror 108C, where about 50% (about 0.25 LB0) is incident. Is reflected and the remaining about 50% (about 0.25 LB0) is transmitted. The transmitted light from the partial reflection / transmission mirror 108C ′ is the total reflection mirror 1
It is incident on 08D and is totally reflected there.

In this way, the four mirrors 108
From A ', 108B, 108C', and 108D, four transmitted lights or reflected lights having substantially the same laser output are extracted as branched laser lights LBA to LBD, respectively.

[0016]

However, in reality, there are variations in the reflectance and the transmittance of the partial reflection / transmission mirror, and the polarization component of the laser light tends to be different between the reflected light and the transmitted light. Therefore, in the conventional laser branching device as described above, it is difficult to accurately divide the laser output of the original laser beam LB0 into equal parts, and the outputs of the respective branch laser beams LBA to LBD vary. For this reason,
There is a problem that the machining quality of the work W varies in the multi-position machining by the simultaneous branching as described above.

Therefore, conventionally, each branched laser beam LBA.about.
Of the LBD, the one with the lowest laser output is used as the reference value,
The other branched laser beams were attenuated by the attenuating plate so that their respective laser outputs were matched (aligned) with the reference value.

For example, in the conventional apparatus shown in FIG. 7, when the laser output of the branched laser beam LBA from the mirror 106A has the lowest value (for example, 0.22LB0), the branched laser beams from the other mirrors 106B, 106C and 106D. The attenuating plate 110 is arranged on the optical axes of the light beams LBA to LBD as shown by the dotted line, and the laser outputs of the respective branched laser beams LBA to LBD are attenuated to the reference value (0.22LB0).

Also in the conventional apparatus shown in FIG. 8, when the laser output of the branched laser beam LBC from the mirror 108C 'has the lowest value (for example, 0.21LB0),
The attenuating plate 110 is also arranged on the optical axes of the branched laser beams LBA, LBB and LBD from the other mirrors 108A ', 108B and 108D, and their laser outputs are set to reference values (0.
It was attenuated to 21 LB0).

However, by using the attenuating plate 110 to align the laser outputs of all the other branched laser beams to the reference value (minimum value) in this way, the laser outputs of those branched laser beams LB are generated by the attenuating plate 110. There was a problem that it was lost in vain and the energy efficiency was lowered. Also, the damping plate 110
Since the laser output attenuation rate in 1) increases and decreases only in a stepwise manner in proportion to the number of plates, it is inconvenient that it is difficult to finely adjust the laser output of the branched laser light.

The present invention has been made in view of the above problems, and the laser outputs of all the branched laser beams can be accurately matched or individually adjusted to a desired value without using an attenuating plate. It is an object of the present invention to provide a laser branching device as described above.

[0022]

In order to achieve the above object, the laser branching device of the present invention has a reflectance and a transmittance with respect to the wavelength of the original laser beam which are substantially continuous in one-dimensional or two-dimensional directions. One or a plurality of changing partial reflection / transmission mirrors are arranged at predetermined positions in predetermined directions so that the laser light incident on each of the partial reflection / transmission mirrors has a desired reflectance and transmittance in a predetermined direction. Adjust the position of each partially reflective mirror to reflect and transmit,
The reflected light or transmitted light from each of the partial reflection / transmission mirrors is used as the branched laser light.

[0023]

In the present invention, since the reflectance and the transmittance can be variably adjusted to arbitrary values by adjusting the position of the mirror in each partial reflection / transmission mirror, there is no problem of variation between the mirrors, and the laser output of the original laser light is Accurate division into equal parts or easy setting and adjustment of laser output for each branched laser beam can be easily performed. Further, it is possible to configure the device using only the partial reflection / transmission mirrors having the same structure, which is advantageous in terms of assembly, storage, maintenance and the like.

[0024]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows the structure of the main part of a laser branching device according to an embodiment of the present invention. This laser branching device is applicable to, for example, the multi-position processing system shown in FIG.

In FIG. 1, the original laser beam LB 0 output from the YAG laser oscillator 10 is a pair of resonance mirrors 1.
Reflection is repeated between two (only one is shown), and after resonance amplification, the light is emitted from the resonance mirror 12.
In this embodiment, four partial reflection / transmission mirrors 14A, 14B, 14C, 1 are arranged on the optical axis of the original YAG laser beam LB0.
The 4Ds are arranged at fixed positions at the same inclination angle (for example, 45 °) and at regular intervals. Partial reflection / transmission mirror 14A with respect to the optical axis of the original YAG laser light LB0
The incident units 18A to 18D are arranged on the reflection sides of the incident units 18A to 14D via the shutters 16A to 16D, and the optical fiber 104 is provided at the other end of the incident units 18A to 18D.
A to 104D are connected.

As shown schematically in FIG. 2, each of the partial reflection / transmission mirrors 14A to 14D emits about 10 YAG laser beams.
The mirror substrate 20 is made of a material that transmits 0%, such as glass or quartz, and the reflectance or transmittance (R, T) for the YAG laser light is (RMAX, TMIN) to ( The partial reflection / transmission film 22 of a multilayer film is coated so as to change substantially continuously in the longitudinal direction (X direction) of the mirror substrate 20 in the range of (RMIN, TMAX).

For example, in this embodiment, (RMAX, TMI
N) is chosen to be (100%, 0%) and (RMIN, TMAX) is chosen to be (0%, 100%). Therefore, one piece of the partial reflection / transmission mirror 14 emits almost 100 YAG laser light depending on the position of the mirror on which the YAG laser light LB is incident.
It is also possible to function as a total reflection mirror for performing% reflection, or as a total transmission plate for transmitting almost 100% of YAG laser light, and an arbitrary value between the total reflection mirror and the total transmission plate. It is also possible to function as a partial reflection / transmission mirror in a narrow sense having reflectance and transmittance (R, T).

As described above, in the partial reflection / transmission mirror 14 of this embodiment, by changing the incident spot position of the YAG laser beam LB incident on this mirror in the substrate longitudinal direction (X direction), the reflected light LBR and the transmitted light are transmitted. The ratio of the laser output of the optical LBT is (100%, 0%) to (0%, 100
%) Can be variably adjusted almost continuously.

3 and 4, the partial reflection / transmission mirror 1 is shown.
4 shows a configuration example of the mirror position adjusting mechanism 24 for variably adjusting the reflectance and transmittance (R, T) of No. 4 of FIG.

FIG. 2 shows a partial reflection / transmission mirror 1.
The vertical holding plate 26 for holding 4 vertically is installed upright on the horizontal support plate 28 so as to be slidable in the X direction, and the ball screw 30 is rotated in the X direction screw hole 26a formed at the base end of the vertical holding plate 26. It is possible through. Ball screw 30 knob 3
By turning 0a, the vertical holding plate 26 and the partial reflection / transmission mirror 14 can be finely moved or displaced in the X direction.

In the structure shown in FIG. 3, a groove 26'd extending in the X direction is formed in a horizontal flange portion 26'c of a vertical holding plate 26 'having a T-shaped cross section, and a bolt 32 is passed through this groove 26'd.
Is to be screwed into a screw hole (not shown) of the horizontal support plate 28 '. By loosening the bolt 32, the vertical holding plate 26 ′ and the partial reflection / transmission mirror 14 are manually moved to the X position.
It can be finely moved or displaced in any direction.

Referring again to FIG. 1, in order to perform simultaneous four-branching with the laser branching device of this embodiment, each partial reflection / transmission mirror 14A-
The reflectance and transmittance (R, T) of 14D may be set and adjusted to the following values.

The reflectance and transmittance (RA, TA) of the first partial reflection / transmission mirror 14A closest to the resonance mirror 12
Should be adjusted to (about 25%, about 75%). The reflectance and transmittance (RB, TB) of the next second partial reflection / transmission mirror 14B may be set and adjusted to (about 33%, about 67%). The reflectance and transmittance (RC, TC) of the third partial reflection / transmission mirror 14C may be set and adjusted to (about 50%, about 50%). Fourth partial reflection / transmission mirror 14D
Reflectance and transmittance (RD, TD) of (about 0%, about 1
00%).

As described above, the partial reflection / transmission mirrors 14A-1
When the reflectance R and the transmittance T of 4D are set and adjusted, the partial reflection / transmission mirrors 14A to 14D reflect and transmit the original YAG laser beam LB0 from the resonance mirror 12 as follows.

First, when the original YAG laser beam LB0 is incident on the first partial reflection / transmission mirror 14A, about 25% of it is there.
Minutes (about 0.25LB0) are reflected and the remaining about 75% (about 0.75LB0) is transmitted.

When the transmitted light (about 0.75LB0) from the first partial reflection / transmission mirror 14A is incident on the second partial reflection / transmission mirror 14B, about 33% (about 0.25L) thereof is there.
B0) is reflected and the remaining about 67% (about 0.50 LB0
) Is transparent.

When the transmitted light (about 0.50LB0) from the second partial reflection / transmission mirror 14B is incident on the third partial reflection / transmission mirror 14C, about 50% (about 0.25L) thereof is there.
B0) is reflected, and about the remaining 50% (about 0.25LB0
) Is transparent.

The transmitted light (about 0.25LB0) from the third partial reflection / transmission mirror 14C is incident on the total reflection mirror 14D and is totally reflected there.

In this way, the four partial reflection / transmission mirrors 14A to 14D have substantially the same laser output.
The two reflected lights are respectively taken out as the branched laser lights LBA to LBD. These branched laser beams LBA to LBD
Simultaneously enter incident units 18A to 18D through shutters 16A to 16D, respectively, and are converged by a condenser lens in the incident units to form optical fibers 104A to 104D.
It is incident on one end surface of D at the same time.

The branched laser beams LBA to LBD simultaneously incident on the one end faces of the optical fibers 104A to 104D pass through the optical fibers 104A to 104D and are emitted from the emitting unit 10.
2A to 102D are transmitted, and the emission unit 102A to
Concentrated irradiation is simultaneously performed from 102D toward each work W.

The shutters 16A to 16D selectively or independently control the transmission of the branched laser beams LBA to LBD as needed to enable time-difference multi-branching. As long as the shutter 16 is open, the branched laser light L
B passes through as it is, and there is no attenuation here.

As described above, according to the laser branching device of this embodiment, the reflectance and the transmittance (R, T) can be variably adjusted to arbitrary values in each of the partial reflection / transmission mirrors 14A to 14D. The problems such as variations in the reflection and transmission characteristics of the laser and variations in the polarization component of the laser light are resolved (easily corrected by variable adjustment), and the laser output of the original laser light LB0 can be accurately obtained without using an attenuator. It is possible to divide into parts, and in the multi-position machining as shown in FIG. 6, the machining quality of the work W can be made constant and the reliability can be improved. Further, since the attenuation plate is not used, the laser output of the laser light does not need to be wastefully lost, and the energy efficiency can be improved.

Further, in the laser branching device of this embodiment,
Since the partial reflection / transmission mirrors 14A to 14D of the same model number are all used, it is also advantageous in terms of inventory management and maintenance costs.

However, when the above-mentioned simultaneous multi-branching is performed, since the set values of the reflectance and the transmittance (R, T) of the partial reflection / transmission mirrors 14A to 14D are predetermined, the respective partial reflections are performed. Variable range (RMAX, TMIN) to (RMIN, T) of reflectance and transmittance for each of the transmission mirrors 14A to 14D
By selecting (MAX) to be a narrow window width including each set value, the resolution of the reflectance and the transmittance of each of the partial reflection / transmission mirrors 14A to 14D is increased, and finer setting adjustment is possible.

For example, in the above example, the variable range (RMAX, TMIN) to (RMIN, TMAX) of the reflectance and the transmittance of the first partial reflection / transmission mirror 14A is (about 30).
%, About 70%) to (about 20%, about 80%) may be used. Regarding the second partial reflection / transmission mirror 14B, its reflectance and transmittance variable ranges (RMAX, TMIN)
~ (RMIN, TMAX) is (about 28%, about 72%) ~ (about 38
%, About 62%) may be used. Regarding the third partial reflection / transmission mirror 14C, the variable range (RMAX, TMIN) to (RMIN, TMAX) of its reflectance and transmittance is (about 4
5%, about 55%) to (about 55%, about 45%) may be used. 4th (last stage) partial reflection transmission mirror 1
4D may replace this with a conventional total internal reflection mirror.

Further, the fourth incidence unit 18D is disposed behind (transmitting side) the third partial reflection / transmission mirror 14C,
The transmitted light from the third partial reflection / transmission mirror 14C is used as the fourth branched laser light LBD, whereby the fourth mirror 14D
It is also possible to omit.

Further, in the above-mentioned embodiment, the case where the simultaneous 4-branch is performed has been described, but other simultaneous multi-branch such as simultaneous 3-branch is also possible, and the individual partial reflection / transmission mirrors 14A to 14A.
By arbitrarily variably adjusting the transmittance and reflectance (R, T) of 14C, it is also possible to set and adjust independent (different) laser output values for each of the branched laser beams LBA to LBD.

The shape and structure of the partial reflection / transmission mirror 14 used in the present invention are not limited to those shown in FIG. For example, as shown in FIG. 5, the reflectance or transmittance (R, T) for laser light is (RMAX, TMIN) to (RMIN, on the front surface or the back surface of the disk-shaped mirror substrate 20 '.
In the circumferential direction (θ direction) of the mirror substrate 20 ′ within the range of TMAX)
The partial reflection / transmission film 22 ′ of the multilayer film may be coated so as to change substantially continuously. In this case, the mirror substrate 20 'can be rotationally displaced in the θ direction by a suitable mirror rotation position adjusting means (not shown).

[0050]

As described above, according to the laser branching device of the present invention, the reflectance and the transmittance with respect to the wavelength of the original laser beam are changed in a one-dimensional or two-dimensional direction by one or a plurality of them. Using a piece of partial reflection transmission mirror,
The position of each partial reflection mirror is adjusted so that the laser light incident on each partial reflection and transmission mirror is reflected and transmitted in a predetermined direction with desired reflectance and transmittance, and reflection from each partial reflection and transmission mirror is performed. Since the light or the transmitted light is the branched laser light, it is possible to accurately match the laser outputs of all the branched laser lights without using an attenuating plate, or individually adjust to a desired value. It is possible to improve energy efficiency, improve adjustment work, and improve reliability such as processing quality.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing the configuration of a laser branching device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a partial reflection / transmission mirror in an example.

FIG. 3 is a perspective view showing a configuration example of a mirror position adjusting mechanism for variably adjusting the transmittance and the reflectance of the partial reflection / transmission mirror in the embodiment.

FIG. 4 is a perspective view showing another configuration example of a mirror position adjusting mechanism for variably adjusting the transmittance and reflectance of the partial reflection / transmission mirror in the embodiment.

FIG. 5 is a perspective view showing a modified example of the partial reflection / transmission mirror in the embodiment.

FIG. 6 is a schematic perspective view showing a multi-point processing system for laser welding.

FIG. 7 is a diagram showing a configuration example of a conventional laser branching device.

FIG. 8 is a diagram showing another configuration example of a conventional laser branching device.

[Explanation of symbols]

 10 Laser oscillator 14A-14D Partial reflection / transmission mirror 18A-18D Incident unit 20,20 'Mirror substrate 22,22' Partial reflection / transmission film 24 Mirror position adjustment mechanism

Claims (1)

[Claims] 1. A laser branching device for generating a plurality of branched laser beams from one original laser beam, wherein the reflectance and the transmittance with respect to the wavelength of the original laser beam change substantially continuously in one-dimensional or two-dimensional directions. One or a plurality of partial reflection / transmission mirrors are arranged at predetermined positions in predetermined directions, and the laser light incident on each of the partial reflection / transmission mirrors is reflected in a predetermined direction with a desired reflectance and transmittance. A laser branching device, wherein the positions of the respective partial reflection mirrors are adjusted so as to be transmitted, and the reflected light or the transmitted light from each of the partial reflection / transmission mirrors is used as the branched laser light.