JPH02284782A - Method for converging laser beams having different wavelengths - Google Patents

Abstract

PURPOSE:To improve machining characteristic by making a laser beam among plural laser beams having different wavelengths incident on a condense lens while having hollow state intensity distribution and making the other laser beam incident on the condense lens through the hollow part thereof and converging and irradiating these on the same optical axis. CONSTITUTION:The axis of a first laser beam 1 is arranged on an axis at the incident side of the condense lens 3 and the axis of a second laser beam 2 having different wavelength is arranged in a crossing direction to the axis at the incident side of the condense lens 3. The first laser beam 1 is made incident on the condense lens 3 as the laser beam having the hollow intensity distribution with a conical outer face mirror 4 and a conical inner face mirrors 5. The second laser beam 2 is made incident on the axis of the condense lens 3 from the side part with a bending mirror 6 positioned at the hollow part of the first laser beam. Both laser beams made incident on the condense lens 3, are converged to the same machining spot 8 on a work 7. By this method, the same spot on the work at the same time can be irradiated with the laser beams having different characteristics and the machining speed and the machining depth can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of condensing laser beams of different wavelengths onto the same spot in laser processing.

[Conventional technology]

As shown in FIG. 6, a conventional method for focusing lasers with different wavelengths on the same optical axis is to combine the second laser C reflected by the bending mirror a and the second laser C with a dichroic mirror. The light converges coaxially at point d, and the workpiece f is irradiated with this light through a condenser lens e.

In addition to the above method, there is also a method disclosed in Japanese Patent Publication No. 80-33595, in which pulsed laser beams emitted from a plurality of oscillators are alternately guided to a workpiece by switching optical paths.

[Problem to be solved by the invention]

In the method shown in FIG. 6 above, if the wavelengths of the second laser 2 and the second laser C are different, when the light is focused by the condensing lens e, the respective lasers b.

The disadvantage is that the focus of C is different and the laser processing characteristics are deteriorated. Also, at the same time, both lasers b.

When C is irradiated, both lasers B and C pass through the same space between the dichroic mirror d and the workpiece F, which causes interference between the lasers and destroys the phase, which is extremely unfavorable for laser processing. Processing cannot be performed properly.

Further, in the method described in Japanese Patent Publication No. 60-33595, it is not possible to irradiate a workpiece with two types of lasers at the same time.

In laser processing, the processing characteristics vary greatly depending on the type of workpiece and the laser used. Therefore, by combining different types of lasers, it is possible to expand the processing target and improve processing accuracy and processing speed. is considered,
Therefore, a method of condensing and irradiating different types of lasers onto the same optical axis is desired.

The present invention has been developed in consideration of the above-mentioned problems, and it is possible to reduce interference between laser beams, prevent deterioration of the characteristics of the laser beam, and prevent differences in focus due to differences in wavelength. Lasers can be irradiated to the same spot on the workpiece at the same time. The object of the present invention is to provide a method of focusing lasers with different wavelengths, which can significantly improve the processing characteristics of various materials.

[Means to solve the problem]

In order to achieve the above object, the method of condensing lasers with different wavelengths according to the present invention includes making one of the lasers with different wavelengths incident on a condensing lens with a hollow intensity distribution, and The other lasers are incident on the condenser lens through the hollow part of the laser having the hollow intensity distribution, and each laser beam is condensed and irradiated onto the same optical axis by the condenser lens.

The focal length of the laser passing through the hollow part at the condensing lens is
This laser was captured by a focus correction lens interposed in its path, so that the focus of the laser passing through the hollow part could be focused on the same arbitrary axis.

One laser with a hollow intensity distribution is focused by a parabolic mirror with a hole in the center, and another laser is passed through the hole in the parabolic mirror and focused on the same optical axis as the above laser. Irradiate light.

The laser that passes through the hole of the parabolic mirror with a hole is focused by a condensing lens on the front side of the parabolic mirror with a hole, and is on the same optical axis as the laser focused by the parabolic mirror with a hole. irradiate with focused light.

[For production]

Lasers with different wavelengths pass through different paths and are focused and irradiated onto the same spot on the workpiece.

Among the lasers of different wavelengths that are focused through the condenser lens, the focal length of the laser that is incident on the central portion of the condenser lens is corrected by the focus correction lens.

〔Example〕

Embodiments of the present invention will be described based on FIGS. 1 to 5.

FIG. 1 shows a first embodiment of the present invention, in which one of the laser 1 and the second laser having different wavelengths, for example, the axis of the laser 1 is located on the incident side of the condenser lens 3. The second laser 2 is arranged on the axis, and the axis of the second laser 2 is arranged in a direction intersecting the axis of the condenser lens 3 on the incident side.

The laser beam 1 enters the condenser lens 3 as a laser beam having a hollow intensity distribution through a conical outer mirror 4 and a conical inner mirror 5.

On the other hand, the second laser beam is introduced from the side at the bending mirror 6 located in the hollow part of the first laser beam having the above-mentioned hollow intensity distribution, and is incident on the axis of the condenser lens 3.

Both laser beams incident on the condensing lens 3 are condensed onto the same slit 8 of the workpiece 7 .

At this time, the second laser 2 passes through a focus correction lens 3a located in front of the bending mirror 6, and thereby the difference in focus due to the difference in wavelength with the first laser 1 is corrected.

FIG. 2 shows a second embodiment of the present invention, in which an unstable laser resonator is used for the first laser 1a to form a laser beam with a hollow intensity distribution, and this is made incident on the condenser lens 3. .

The second laser 2 is incident on the axis of the condensing lens 3 through the hollow part of the second laser 2 via the focus correction lens 3a and the bending mirror 6, as in the first embodiment, and both lasers 1 and 2 are focused on the same processing spot 8 by a condensing lens 3.

FIG. 3 shows a third embodiment of the present invention, in which a dichroic mirror is used as the mirror 9 arranged obliquely on the incident axis of the condenser lens 3, and the first beam 1b is transmitted as it is. The second beam 2 is reflected and enters the condenser lens 3 . At this time, the first beam 1b
is larger than the axial projected area of the mirror 9, and the condenser lens 3
A device with an intensity distribution smaller than the effective area of is used.

FIG. 4 shows a fourth embodiment of the present invention, in which the second laser 2a is formed into a hollow shape, and the hollow second laser 2a is formed into a hollow shape.
a is reflected and condensed by a perforated parabolic mirror 11 having a hole 10 at its axial center, and the workpiece 7 is irradiated with condensed light.

On the other hand, the router 1 is reflected by the bending mirror 6 toward the hole 10 of the parabolic mirror 11 with a hole, and then is reflected by the condenser lens 3 in front of the parabolic mirror 11 with a hole. The beam is condensed and passed through the hole 10 of the perforated paraboloid #111, and is condensed and irradiated onto the same processing spot 8 as the second laser 2a.

FIG. 5 shows a fifth embodiment, which is an application example of the method shown in FIG.
2, the fiber injection unit (collimator) 13
At this point, the workpiece 7 is focused and irradiated through the hole 10 of the perforated parabolic mirror 11.

The second laser 2a in the fourth and fifth embodiments is formed into a hollow shape in the same manner as the laser 1[deg.]a in the first and second embodiments.

〔Effect of the invention〕

According to the present invention, lasers with different wavelengths are focused and irradiated onto the same processing spot 8 on the workpiece 7 through different paths.

Therefore, the interference between lasers with different wavelengths is small, the characteristics of the laser beam are not deteriorated, and the difference in focus due to the difference in wavelength can be prevented.This allows lasers with different characteristics to irradiate the same spot on the workpiece at the same time. It is possible to significantly improve the machining characteristics of various materials, ie, machining speed and machining depth.

Processing of materials that are difficult to laser process using conventional methods, such as A,
In laser processing of 9 and Cu alloys, excimer, YAG
Lasers and CO2 lasers have different absorption coefficients, and CO2 lasers mostly reflect, making laser processing very difficult.

Furthermore, although excimer and YAG lasers have relatively high absorption coefficients, their output is small, so it has been difficult to use them with a thickness exceeding 0.1 m.

On the other hand, excimer and 002 laser, or YAG
Simultaneous laser irradiation with a combination such as laser and CO2 laser, or excimer or YAG laser for preheating.
By irradiating CO2 laser during the main processing, it has become possible to process materials that were previously difficult.

Even if the material is difficult to laser-process with a CO2 laser, when the temperature of the workpiece increases due to irradiation with an excimer or YAG laser, the absorption coefficient increases and the material can be efficiently absorbed even with a CO2 laser.

[Brief explanation of drawings]

1, 2, 3, 4, and 5 are schematic explanatory diagrams showing different embodiments of the present invention, and FIG. 6 is a schematic explanatory diagram showing a conventional example. be. 1, la, lb, 2.2a are lasers, 3 is a condensing lens,
3a is a focus correction lens, 41 and n4 [external mirror 5
is a conical inner mirror, 6ζ is a bending mirror, 7 is a workpiece, 8C is a bending mirror, 10 is a hole, 11 is a parabolic mirror with a hole, 12 is an optical fiber, and 13 is a fine injection unit. Company Komatsu Manufacturing J Inori

Claims (4)

[Claims] (1) One laser out of a plurality of lasers with different wavelengths is incident on a condensing lens with a hollow intensity distribution,
Further, another laser beam is incident on a condensing lens through the hollow part of the laser having a hollow intensity distribution, and each laser beam is condensed and irradiated on the same optical axis by the condensing lens. different laser focusing methods. (2) The focal length of the laser passing through the hollow part with the condensing lens is corrected by a focus correction lens inserted in the path of this laser, and the focus of the laser passing through the hollow part is focused on an arbitrary coaxial axis. 2. The method of focusing lasers of different wavelengths according to claim 1, wherein (3) One laser with a hollow intensity distribution is focused by a parabolic mirror with a hole in the center, and another laser is passed through the hole of the parabolic mirror with the same optical axis as the above laser. A method of condensing lasers with different wavelengths, which is characterized by condensing irradiation onto the top. (4) The laser that passes through the hole in the parabolic mirror with a hole is focused by a condensing lens on the front side of the parabolic mirror with a hole, and the same light is the same as the laser focused by the parabolic mirror with a hole. 4. The method of focusing lasers of different wavelengths according to claim 3, wherein the focusing is carried out on an axis.