JP4480261B2 - Mirror cooling structure and cooling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention improves the cooling effect of the output mirror and rear mirror of a laser oscillator, reduces the thermal lens effect of the mirror, suppresses thermal distortion, and stabilizes the beam mode and the laser output. Regarding the method.
[0002]
[Prior art]
The output mirror, rear mirror, etc. of the laser oscillator use partially transmissive mirrors. However, as the laser output increases, the mirror itself is affected by the heat absorption from the laser light, causing the so-called “thermal lens effect”. As shown in FIG. 2, a cooling unit 1b using cooling water is provided in the block 1 on the substrate side to which the mirror is attached because the mirror is adversely affected, and the mirror Mi surface is brought into contact with the block 1 and indirectly cooled. This is usually done.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional example, as shown in FIG. 3, when the edge Ed of the peripheral portion of the mirror Mi is enlarged, the radius of curvature R of the normal mirror Mi has a value close to about 30 m. As shown in the figure, the edge Ed is cooled while being in line contact with the block 1 having the cooling portion 1b, and the cooling effect is lowered and the thermal lens effect is likely to occur. When this occurs, distortion due to heat is generated, and adverse effects such as changes in beam diameter, beam mode, and laser output occur.
[0004]
When the above-described state is induced, as a result, the laser processing operation becomes unstable and the quality is adversely affected.
[0005]
The above-mentioned problem is an important technical problem in the recent situation of high output and high precision machining.
[0006]
The present invention has been made in view of the above situation, and an object of the present invention is to provide a mirror cooling structure and a cooling method that add a cooling function to enable improvement in cooling effect and cooling uniformity.
[0007]
[Means for Solving the Problems]
The present invention can solve the above problems by providing the following configuration.
[0008]
(1) A mirror cooling structure used in a laser oscillator, in which a mirror is fitted to a block having a laser beam passage hole at the center and a cooling portion around the laser beam passage hole. An inner periphery of the laser beam passage hole of the mirror pressing member in a state where the mirror pressing member is mounted so that the laser beam can pass through the mirror and the peripheral edge portion of the mirror is in contact with the block. And a plurality of oblique winding coil springs disposed on the peripheral edge of the mirror, and heat is released to the block side having the cooling portion via the oblique winding coil springs. Cooling structure.
[0009]
(2) A method for cooling a mirror used in a laser oscillator, in which a mirror is fitted to a block having a laser beam passage hole at the center and a cooling portion around the laser beam passage hole. An inner periphery of the laser beam passage hole of the mirror pressing member in a state where the mirror pressing member is mounted so that the laser beam can pass through the mirror and the peripheral edge portion of the mirror is in contact with the block. And a plurality of oblique winding coil springs disposed on the peripheral edge of the mirror, and heat is released to the block side having the cooling portion via the oblique winding coil springs. Cooling method.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
[0013]
FIG. 1A is a cross-sectional explanatory view of a mirror cooling structure in Embodiment 1 according to the present invention, FIG. 1B is a cross-sectional explanatory view of a mirror cooling structure in Embodiment 2 according to the present invention, and FIG. FIG. 3 is a sectional view of the cooling structure, FIG. 3 is a partially enlarged sectional view of the mirror bending state, and FIG. 4 is a state explanatory view of the spring gasket.
[0014]
Hereinafter, description will be given with reference to the drawings.
[0015]
Example 1
An obliquely wound coil spring (or spring gasket) 4 is appropriately disposed on the side surface of a mirror 3 used in a laser oscillator, and has a cooling structure that enhances the cooling effect through thermal contact with the laser beam Le at the center. The laser beam Le can pass through the mirror 3 through the mirror pressing member 2 fitted with the mirror 3 to the block 1 having the hole 1a and the cooling portion 1b around the laser beam Le passing hole 1a. In addition, in a state in which the peripheral edge 3a of the mirror 3 is mounted in close contact with the block 1, the inner periphery of the laser light Le passage hole 2a of the mirror pressing member 2 and the peripheral edge of the mirror 3 For example, a plurality of oblique winding coil springs 4 are equally arranged, and heat is released through the oblique winding coil springs 4 to the block 1 side having the cooling portion 1b. To.
[0016]
In addition, as shown in FIG. 4, when the mirror 3 is not inserted, the obliquely wound coil spring 4 forming the spring gasket is in a non-contact state when there is no load as shown in FIG. When the mirror 3 is inserted, the contact area in the maximum load state when the mirror 3 is set as shown in (c) is maximized by the adjacent inclined winding coils being in contact with each other and in contact with each other. As the contact area increases, the thermal conductivity for cooling increases.
[0017]
In addition, in the case of the obliquely wound coil spring 4 forming this spring gasket, as is apparent from the structure, since it has elasticity, a large force is not applied to the mirror 3, and therefore, there is a concern about mirror deformation and the like. Nonetheless, a heat flow is generated along the arrow A shown in FIG. 1A, and the cooling effect can be improved.
[0018]
(Example 2)
In the second embodiment, in the state where the shape of the mirror 7 is changed so that the peripheral portion 7a of the mirror 7 in contact with the block 1 having the cooling portion 1b is in close contact with the block 7, the peripheral portion of the mirror is the block. The contact surface along the peripheral edge is made into a mirror shape having a flat surface with increased flatness so as to make surface contact with the surface, and the contact heat transfer area of the mirror for releasing heat is enlarged.
[0019]
For other symbols, 5 and 6 indicate an O-ring gasket or the like.
[0020]
The other symbols are the same as described above, and will be omitted.
[0021]
As described above, (1) By using the obliquely wound coil spring (spring gasket) 4 in contact with and in close contact with the side surface of the mirror 3, uniform thermal contact can be achieved without applying excessive force to the mirror 3. It is possible to improve the cooling capacity and cooling effect of the mirror 3 by improving.
[0022]
(2) By making the contact surface peripheral portion 7a of the mirror 7 in contact with the block 1 having the cooling portion 1b into a flat surface with high flatness, the contact area is enlarged, and the thermal contact property is made uniform. As in (1), the cooling capacity and cooling effect of the mirror 7 can be improved.
[0023]
In the present embodiment, the application has been described as a measure for preventing the thermal lens effect in the mirror, but application to lenses such as other condensing lenses is also possible.
[0024]
【The invention's effect】
According to the present invention, by adding a cooling function and improving the cooling effect and enabling cooling uniformity, the thermal lens effect of the mirror is reduced, thus reducing the thermal distortion of the mirror, the beam diameter, the beam mode, The laser output can be stabilized, and as a result, the laser processing operation can be stabilized and the reliability of the processing machine can be improved.
[0025]
In addition, the thermal lens effect preventing function in the present invention can be widely applied to other lenses such as a condenser lens.
[Brief description of the drawings]
1A is a cross-sectional view of a mirror cooling structure in Embodiment 1 according to the present invention, and FIG. 1B is a cross-sectional view of a cooling structure of a mirror in Embodiment 2 according to the present invention. Structural cross-sectional explanatory diagram [Fig. 3] Mirror bending situation cross-sectional partial enlarged explanatory diagram [Fig. 4] Spring gasket state explanatory diagram [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Block 1a, 2a Laser beam passage hole 1b Cooling part 2 Mirror pressing member 3 Mirror 3a Peripheral part 4 Inclined winding coil spring (spring gasket)
5, 6 O-ring gasket 7 Mirror 7a Peripheral edge Ed Edge Mi Mirror Le Laser light

Claims (2)

  Mirror cooling structure used in a laser oscillator, having a laser beam passage hole at the center, and a mirror holding member in which a mirror is fitted to a block having a cooling portion around the laser beam passage hole Is mounted so that the laser beam can pass through the mirror and the peripheral edge of the mirror is in close contact with the block, the inner periphery of the laser beam passage hole of the mirror pressing member, and a mirror A mirror cooling structure characterized in that a plurality of obliquely wound coil springs are disposed on the peripheral side of the mirror, and heat is released to the block side having the cooling part via the obliquely wound coil springs.   A method of cooling a mirror used in a laser oscillator, comprising a laser beam passage hole in a central portion and a mirror holding member in which a mirror is fitted to a block having a cooling portion around the laser beam passage hole. Is mounted so that the laser beam can pass through the mirror and the peripheral edge of the mirror is in close contact with the block, the inner periphery of the laser beam passage hole of the mirror pressing member, and a mirror A cooling method for a mirror, wherein a plurality of obliquely wound coil springs are disposed on the peripheral side of the mirror, and heat is released to the block side having the cooling part via the obliquely wound coil springs.

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