JPH1093179A - Laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser oscillator, which enables stable emission of a laser beam of desired characteristic and state from an output coupling mirror, even when the laser output is large. SOLUTION: A laser oscillated by a discharge tube 4 is emitted as a laser beam 7 through an output coupling mirror 11 and a window member 12, so arranged as to face the output coupling mirror 11 via a clearance 14. A cooling fluid 15 is made to flow through the clearance 14, thus cooling the output coupling mirror 11 and the window member 12. Therefore, the effect of thermal distortion on the laser beam 7 to be emitted is prevented, and the laser beam 7 of desired characteristic and state may be emitted stably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillator, and more particularly to a laser oscillator mounted on a laser processing apparatus for processing a workpiece such as a steel material.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional laser oscillator. In the figure, 1 is an output coupling mirror, 3 is a total reflection mirror, 4 is a discharge tube, 5
Is a holder, 6 is cooling water, 7 is a laser beam, and 8 is a cooling water inflow section. In FIG. 4, an output coupling mirror 1 is disposed at one end of a discharge tube 4 formed to be elongated, and emits a laser beam oscillated by the discharge tube 4 in the direction of a processing side (arrow A in the drawing) as a laser beam. I do. The output coupling mirror 1 is supported by a holder 5. A cooling water inflow portion 8 is formed near the output coupling mirror 1 of the holder 5, and the cooling water 6 flows through the cooling water inflow portion 8, thereby indirectly outputting the output coupling mirror via the holder 5. 1 is to be cooled.

A gas such as carbon dioxide gas is sealed in the discharge tube 4 as a laser medium. Further, the discharge tube 4 is formed to be elongated, so that a long discharge region is secured, and the output is increased. The total reflection mirror 3 is arranged at a position facing the output coupling mirror 1 via the discharge tube 4, and forms a resonator with the discharge tube 4.

[0004]

By the way, in the case of the laser oscillator as described above, if the laser output of the discharge tube 4 is large, light absorbed by the output coupling mirror 1 increases and thermal distortion is easily induced. In some cases, the quality of the emitted laser beam deteriorates. Specific effects of thermal distortion include changes in beam mode and divergence angle.

The present invention has been made in view of the above problems, and provides a laser oscillator capable of stably emitting a laser beam of a desired property from an output coupling mirror even when a laser output is large. It is intended to do so.

[0006]

The present invention has the following features to attain the object mentioned above. That is, the invention according to claim 1 includes a discharge tube, and an output coupler for emitting a laser oscillated by the discharge tube in a target direction as a laser beam, wherein the output coupler includes an output coupling mirror, the output coupler, A window member spaced apart from the coupling mirror and a fluid flow path for supporting the output coupling mirror and the window material and for flowing a cooling fluid through a clearance secured between the output coupling mirror and the window material; A laser oscillator comprising: a holder to be formed;

According to the present invention, the output coupling mirror is cooled by the cooling fluid flowing in the fluid flow path, thereby preventing the laser transmitted through the output coupling mirror and the window material from being affected by thermal distortion.

According to the second aspect of the present invention, a concave or convex curved surface is formed on at least one surface of the window material. .

According to the present invention, the divergence angle and the like of the emitted laser beam are corrected by the curved surface of the window material, and the desired beam mode and divergence angle are obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a laser oscillator according to the present invention will be described.
An embodiment will be described with reference to FIGS. In the drawing, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof will be simplified. In FIG. 1, reference numeral 10 denotes an output coupler. The output coupling body 10 includes an output coupling mirror 11, a window member 12 spaced apart from and facing the output coupling mirror 11, and a holder 13 supporting the output coupling mirror 11 and the window member 12. The output coupling mirror 11 is arranged so as to face the total reflection mirror 3 at one end in the longitudinal direction of the discharge tube 4.

The holder 13 has an output coupling mirror 11 and a window material 1.
Fluid 1 for cooling in clearance 14 secured between
5 (cooling gas) is formed. A large amount of fluid 15 is passed through the fluid flow path 16 from one of the through holes 17 opened on both sides facing each other via the clearance 14 (in the direction of the arrow in FIG. 1).

The output coupling mirror 11 and the window material 12 are preferably made of zinc selenium or the like. However, the fluid flow path 16
It is necessary to have a strength that can withstand the pressure of the fluid 15 flowing through the fluid.

The fluid 15 is preferably a cooling gas such as nitrogen gas or dry compressed air. However, high-purity cooling gas from which impurities such as oil are removed is used.

According to the laser oscillator of the present invention, the output coupling mirror 11 and the window material 12 are directly and forcibly cooled by the fluid 15 flowing through the fluid flow path 16, so that the emitted laser beam 7 is thermally strained. Therefore, a laser beam 7 having a desired property can always be obtained stably.

FIG. 2 shows the relationship between the emitted laser beam diameter and the optical path length in a laser oscillator prototyped by the inventors based on the present invention. According to FIG. 2, it is apparent that the target laser beam diameter can be obtained more stably with the laser oscillator of the present invention than with the conventional laser oscillator with respect to the output optical path length L (m) in the working beam range. It is.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In FIG. 3, the laser oscillator according to the present embodiment is different from the laser oscillator according to the first embodiment only in the window member 18. The window material 18 is a laser beam 7
Has a convex curved surface 19 in the emission direction.

According to the laser oscillator of this embodiment, the laser beam 7 transmitted through the window member 18 is formed by the convex curved surface 19.
Is suppressed, and the laser beam 7 having a desired property can be emitted stably. Thereby, beam quality suitable for processing can be obtained, and utilization efficiency is improved.

The curved surface formed on the window material may be formed on the entrance side or on both the entrance and exit sides of the window material, and may have a concave shape or an irregular curvature. The position and shape of the curved surface are appropriately selected for the purpose of obtaining a laser beam having a desired property.

[0019]

As described above, according to the laser oscillator of the first aspect, there is provided a discharge tube, and an output coupler for emitting a laser oscillated by the discharge tube as a laser beam in a target direction, The output coupling body includes an output coupling mirror, a window member spaced apart from and facing the output coupling mirror, and a clearance secured between the output coupling mirror and the window material, supporting the output coupling mirror and the window material. And a holder for forming a fluid flow path for allowing a cooling fluid to flow therethrough. The output coupling mirror and the window material are directly forcibly cooled by the cooling fluid flowing through the fluid flow path, and the output coupling mirror and the window material are transmitted. The laser beam does not have the effect of thermal distortion, so that a laser beam of desired properties can be obtained stably, and when this is used for laser processing of steel materials, the processing accuracy is stable. Improves the quality of processed products Excellent effects such can Rukoto.

In the laser oscillator according to the second aspect, since the concave or convex curved surface is formed on at least one surface of the window material, the divergence angle of the emitted laser beam is suppressed, and the laser output is wasted. In addition to this, there is an excellent effect that a laser beam having a desired property can always be emitted stably and reliably.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a first embodiment of a laser oscillator according to the present invention.

FIG. 2 is a diagram showing an effect of the laser oscillator of the present invention, and shows a relationship between an emitted laser beam diameter and an optical path length.

FIG. 3 is a front sectional view showing a second embodiment of the laser oscillator of the present invention.

FIG. 4 is a front sectional view showing a conventional laser oscillator.

[Explanation of symbols]

 Reference Signs List 4 discharge tube 7 laser beam 10 output coupling body 11 output coupling mirror 12 window material 13 holder 14 clearance 15 fluid 16 fluid flow path 18 window material 19 curved surface (convex curved surface)

Claims (2)

[Claims] A discharge tube (4) and an output coupler (10) for emitting a laser oscillated by the discharge tube as a laser beam (7) in a target direction, wherein the output coupler is an output coupling mirror. (11) a window member (12, 18) which is spaced apart from the output coupling mirror and opposed to the output coupling mirror; a clearance which supports the output coupling mirror and the window material and is secured between the output coupling mirror and the window material; (14) Cooling fluid (1)
5) A laser oscillator comprising: a holder (13) for forming a fluid flow path (16) through which a fluid flows. 2. The laser oscillator according to claim 1, wherein a concave or convex curved surface is formed on at least one surface of the window material.