JPH08211211A - Cooling device of reflection mirror for high power laser - Google Patents

Abstract

PURPOSE: To prevent the deformation of the reflection mirror of a high power laser caused by the pressure of coolant. CONSTITUTION: When coolant R flows into a coolant groove 5, the pressure of the coolant R is directly applied to a back plane 1b of a metallic mirror 1. Since the rigidity of a cover material 15 is smaller than the rigidity of the mirror 1, the material 15 is deflected to a space 23 side by the pressure of the coolant R, the deformation of the mirror 1 is prevented and as a result, a high surface precision of the mirror 1 is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a high-power laser reflecting mirror, and more particularly to a cooling device for a high-power laser reflecting mirror that prevents a temperature rise due to laser light absorption of a metal mirror for a high-power laser.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a conventional cooling device for a high-power laser reflection mirror.

A reflection mirror 101 for a high-power laser (laser light of several hundred W or more) is held by a holder 102, and a refrigerant is contained between a back surface 101b of the reflection mirror 101 and a mirror facing portion 102a of the holder 102 facing the back surface 101b. A chamber 105 is formed. A coolant supply port 110 and a coolant discharge port 111 are provided in the mirror facing portion 102a of the holder 102, respectively. The refrigerant supply port 110 has a refrigerant supply side joint 11
2, a refrigerant discharge side joint 113 is inserted into the refrigerant discharge port 111, a refrigerant supply side joint 112 has a refrigerant supply side tube (not shown), and a refrigerant discharge side joint 113 has a refrigerant discharge side tube (not shown). Connected.

Refrigerant R such as air and water flows into the refrigerant storage chamber 105 from the refrigerant supply side tube through the refrigerant supply side joint 112, and is discharged to the refrigerant discharge side tube through the refrigerant discharge side joint 113. At this time, the heat of the reflection mirror 101 is taken by the refrigerant R, and the reflection mirror 101 is cooled. In this way, the reflection mirror 101 for high power laser
The temperature rise due to the absorption of the laser light is suppressed.

FIG. 4 is a sectional view showing another conventional cooling device for a high-power laser reflection mirror, and FIG. 5 is a plan view showing the back surface of the high-power laser reflection mirror shown in FIG.

A plurality of scroll-shaped coolant grooves 205 are provided on the back surface 201b of the reflection mirror 201 for a high-power laser, and the end portion 205b of each coolant groove 205 has a reflection mirror 2.
A discharge hole 214 provided at the center of the back surface 201b of 01
Is in communication with A disk-shaped cover member 215 is fitted on the back surface 201b of the reflection mirror 201, and the cover member 21
5, the coolant groove 205 and the discharge hole 214, the cover member 2
A coolant channel is formed between 15 and the reflection mirror 201. The cover member 215 includes a starting end portion 2 of each refrigerant groove 205.
05a, a plurality of refrigerant supply ports 210, and discharge holes 2
14 and a refrigerant outlet 211 facing each other. The refrigerant supply port 210 has a refrigerant supply side joint 212
However, a refrigerant discharge side joint 213 is inserted into the refrigerant discharge port 211, a refrigerant supply side tube (not shown) is connected to the refrigerant supply side joint 212, and a refrigerant discharge side tube (not shown) is connected to the refrigerant discharge side joint 213. Has been done.

The refrigerant R flows into the refrigerant groove 205 from each refrigerant supply side tube through the refrigerant supply side joint 212, and from the terminal end 205b of the refrigerant groove 205 into the discharge hole 214,
It is discharged from the discharge hole 214 to the refrigerant discharge side tube through the refrigerant discharge side joint 213.

Similar to the cooling device of FIG. 3, the heat of the reflection mirror 201 is taken by the refrigerant R to cool the reflection mirror 201, and the temperature rise of the reflection mirror 201 for high-power laser due to the absorption of laser light is suppressed. .

[0009]

However, in both of the conventional cooling devices shown in FIGS. 3 and 4, the reflection mirror 101,
Since the structure in which the reflection mirrors 101 and 201 are cooled by directly supplying the coolant R to the back surfaces 101b and 201b of the 201, the surfaces 101a and 201a of the reflection mirrors 101 and 201 are deformed by the supplied pressure. However, there is a problem that the surface accuracy is deteriorated. For example, in the high power laser transmission optical system, the reflection mirror 10
When the surfaces 101a and 201a of the reference numerals 1 and 201 are deformed, the focused beam pattern is disturbed.

Further, since any of the conventional cooling devices merely cools the back surfaces 101b and 201b of the reflection mirrors 101 and 201 by directly supplying a constant flow rate of the refrigerant R,
Depending on the environmental temperature where the reflection mirrors 101 and 201 are installed, the reflection mirrors 101 and 201 are cooled too much, and the surfaces 101a and 201a of the reflection mirrors 101 and 201 are condensed or deformed. There is a problem that 101 and 201 are deformed.

The present invention has been made in view of the above circumstances, and its object is to prevent deformation of the reflection mirror for a high-power laser due to the pressure of the refrigerant and to prevent condensation or deformation due to excessive cooling or insufficient cooling. A cooling device for a reflection mirror for an output laser is provided.

[0012]

In order to solve the above-mentioned problems, a cooling device for a reflecting mirror for a high-power laser according to a first aspect of the present invention covers the back surface of the reflecting mirror for a high-power laser with a cover member. Cooling of the reflection mirror for high-power laser, which forms a coolant channel between the back surface of the reflection mirror and the cover member, and circulates the coolant in this coolant channel to suppress the temperature rise of the reflection mirror due to absorption of laser light. In the device,
The rigidity of the cover member is weaker than the rigidity of the high-power laser reflection mirror.

According to a second aspect of the present invention, there is provided a cooling device for a high-power laser reflecting mirror according to the second aspect, in the vicinity of a coolant supply port formed in the cover member for supplying a coolant to the coolant channel, A screw is provided to connect the reflecting mirror and the cover member.

Furthermore, in the cooling device for a high-power laser reflection mirror according to a third aspect of the present invention, based on a temperature detection means for detecting the temperature of the high-power laser reflection mirror and a detection signal from the temperature detection means. Control means for adjusting the flow rate or temperature of the refrigerant to control the temperature of the high-power laser reflection mirror.

According to a fourth aspect of the present invention, in the cooling device for a high-power laser reflection mirror, a coolant is circulated on the back surface of the high-power laser reflection mirror to suppress the temperature rise of the reflection mirror due to the absorption of laser light. In the cooling device for the high-power laser reflection mirror, the temperature detection means for detecting the temperature of the high-power laser reflection mirror, and adjusting the flow rate or temperature of the refrigerant based on the detection signal from the temperature detection means. And a control means for controlling the temperature of the high-power laser reflection mirror.

[0016]

In the cooling device for a high-power laser reflection mirror according to the first aspect of the present invention, when the coolant flows into the coolant channel, the pressure of the coolant is directly applied to the back surface of the high-power laser reflection mirror. Since the rigidity of the member is weaker than the rigidity of the high-power laser reflection mirror, the cover member is bent by the pressure of the refrigerant, and the high-power laser reflection mirror is prevented from being deformed.

In the cooling device for a high-power laser reflection mirror according to a second aspect of the present invention, the high-power laser reflection mirror and the cover member are screwed together near the periphery of the coolant supply port. Even if the cover member is deformed by the pressure of 1, the leakage of the refrigerant from the refrigerant channel can be prevented.

Further, in the cooling device for a high-power laser reflecting mirror according to the third aspect of the present invention, the deformation of the high-power laser reflecting mirror due to the pressure of the refrigerant can be suppressed and the high-power laser reflecting mirror can be suppressed. When installed in an environment where the temperature and humidity fluctuate greatly, the high-power laser reflection mirror is maintained at a temperature according to the environmental temperature, preventing condensation and deformation on the surface of the high-power laser reflection mirror caused by overcooling or insufficient cooling. be able to.

Further, in the cooling device for a high-power laser reflection mirror according to a fourth aspect of the present invention, when the high-power laser reflection mirror is installed in an environment where temperature and humidity fluctuate greatly,
The high-power laser reflection mirror is maintained at a temperature according to the ambient temperature, and it is possible to prevent dew condensation or deformation on the high-power laser reflection mirror surface caused by excessive cooling or insufficient cooling.

[0020]

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

FIG. 2 is a rear view showing a cooling device for a high-power laser reflecting mirror according to an embodiment of the present invention, and FIG. 1 is a sectional view taken along the line AA of FIG.

A plurality of scroll-shaped coolant grooves 5 are provided on the back surface 1b of a metal mirror (reflection mirror for high-power laser) 1 made of molybdenum, and the end portions 5b of each coolant groove 5 are on the back surface 1b of the metal mirror 1. It communicates with the discharge hole 14 provided at the center. A brass disk-shaped cover member 15 is joined to the back surface 1b of the metal mirror 1 by a seal screw 16, and the cover member 15 and the coolant groove 5 and the discharge hole 14 form a cover member 1
A coolant flow path is formed between the metal plate 5 and the metal mirror 1. An annular groove is provided on the mirror contact surface 15a of the cover member 15, and an O-ring 17 is fitted into the annular groove to ensure the sealing property of the refrigerant passage.

The rigidity of the cover member 15 is weaker than that of the metal mirror 1. The cover member 15 is provided with a plurality of refrigerant supply ports 10 facing the starting ends 5 a of the respective coolant grooves 5 and a coolant discharge port 11 facing the discharge holes 14.
In the vicinity of the periphery of the coolant supply port 10, the metal mirror 1 and the cover member 15 are joined by the seal screw 16.

The cover member 15 and the metal mirror 1 are housed in the holder 2. A central hole 18 is provided in the mirror facing portion 2 a of the holder 2, and the boss portion 19 of the cover member 15 is inserted into the central hole 18. An O-ring 20 is fitted in an annular groove on the outer peripheral surface of the boss portion 19 so that the refrigerant R does not enter between the boss portion 19 of the cover member 15 and the mirror facing portion 2a of the holder 2.

The cover member 15 and the mirror facing portion 2a of the holder 2 are coupled by a screw 21, and a space 23 is formed between the cover member 15 and the mirror facing portion 2a of the holder 2. The outer peripheral edge of the surface 1 a of the metal mirror 1 is supported by the spacing ring 3 and the pressing ring 4. An O-ring 21 is fitted in an annular groove at the head of the seal screw 16 so that the refrigerant R does not leak from between the head of the screw 21 and the cover member 15.

In the mirror facing portion 2a of the holder 2, holes 22 facing the coolant supply port 10 are provided at regular intervals along the circumferential direction. A refrigerant supply side joint 12 is inserted into the refrigerant supply port 10, and a refrigerant supply side tube 24 is connected to the refrigerant supply side joint 12. A refrigerant discharge side tube 25 is connected to the refrigerant discharge port 11 via a refrigerant discharge side joint 13.

A temperature sensor (temperature detecting means) 7 is embedded in the metal mirror 1 via a filler 8 (for example, a silicon compound) having high thermal conductivity and elasticity, and the output end of the temperature sensor 7 is illustrated. Not connected to a flow rate or temperature controller system (control means) composed of a hybrid recorder, a flow rate or temperature controller, or the like.

The refrigerant R flows from each refrigerant supply side tube 24 into the refrigerant groove 5 through the refrigerant supply side joint 12, flows from the terminal end 5b of the refrigerant groove 5 into the discharge hole 14, and from the discharge hole 14 to the refrigerant discharge side joint. Refrigerant discharge side tube 25 through 13
Is discharged to At this time, the heat of the metal mirror 1 is taken by the refrigerant R, and the metal mirror 1 is cooled. The refrigerant R
There is no problem in reversing the inflow and outflow of.

When the refrigerant R flows into the refrigerant groove 5, the pressure of the refrigerant R is directly applied to the back surface 1b of the metal mirror 1, but the rigidity of the cover member 15 is weaker than that of the metal mirror 1 as described above. The pressure causes the cover member 15 to bend toward the space 23, and deformation of the metal mirror 1 is suppressed. Therefore, the high surface precision of the metal mirror 1 can be maintained, and high-power laser light (laser light of several hundred W or more) can be stably condensed to a long distance so as to have a minimum converged diameter. .

Further, since the seal screw 16 connects the metal mirror 1 and the cover member 15 in the vicinity of the refrigerant supply port 10, even if the cover member 15 is deformed by the pressure of the refrigerant R, the refrigerant R leaks. Can be prevented by the O-ring 17.

Further, since the temperature sensor 7 is embedded in the metal mirror 1 and the flow rate or the temperature controller system controls the flow rate or temperature of the refrigerant R according to the temperature detected by the temperature sensor 7, for example, the metal mirror 1 Even if is installed in an environment in which the temperature and humidity fluctuate greatly, the metal mirror 1 can be maintained at a temperature according to the environmental temperature. For example, when the temperature of the metal mirror 1 is too low with respect to the ambient temperature, the coolant flow rate is reduced or the coolant temperature is raised, and when the temperature of the metal mirror 1 is too high with respect to the ambient temperature, the coolant flow rate is increased or the coolant temperature is lowered. Or
As a result, it is possible to prevent dew condensation or deformation of the surface 1a of the metal mirror 1 due to excessive cooling, and prevent deformation of the metal mirror 1 due to insufficient cooling, and further stabilize the function of the metal mirror 1 of reflecting high-power laser light. be able to.

[0032]

As described above, according to the cooling device for a high-power laser reflection mirror of the invention described in claim 1, the coolant flows into the coolant passage, and the pressure of the coolant is high-power laser reflection mirror. However, since the rigidity of the cover member is weaker than the rigidity of the high-power laser reflection mirror, the pressure of the refrigerant causes the cover member to bend, suppressing the deformation of the high-power laser reflection mirror. The high surface accuracy of the reflecting mirror for use is maintained, and high-power laser light can be stably condensed to a long distance with a minimum condensed diameter.

According to the cooling device for a high-power laser reflection mirror of the second aspect of the present invention, the high-power laser reflection mirror and the cover member are screwed together in the vicinity of the periphery of the coolant supply port. Even if the cover member is deformed by the pressure of the refrigerant, it is possible to prevent the refrigerant from leaking from the refrigerant channel.

Further, according to the cooling device for a high-power laser reflection mirror of the present invention, the deformation of the high-power laser reflection mirror due to the pressure of the refrigerant is suppressed, and the high-power laser reflection mirror has a high surface. In addition to maintaining accuracy, when the high-power laser reflection mirror is installed in an environment where the temperature and humidity fluctuate greatly, the high-power laser reflection mirror is maintained at a temperature that corresponds to the ambient temperature, which causes excessive cooling or cooling. It is possible to prevent dew condensation and deformation of the surface of the high-power laser reflection mirror caused by the shortage, and it is possible to further stabilize the function of the high-power laser reflection mirror that reflects high-power laser light.

According to the cooling device for a high-power laser reflection mirror of the present invention, when the high-power laser reflection mirror is installed in an environment where the temperature and humidity greatly fluctuate, the high-power laser reflection mirror is reflected. The mirror is maintained at a temperature according to the ambient temperature, and it is possible to prevent condensation and deformation of the surface of the high-power laser reflection mirror caused by overcooling or insufficient cooling. The function can be further stabilized.

[Brief description of drawings]

1 is a cross-sectional view taken along the line AA of FIG.

FIG. 2 is a plan view of a cooling device for a high-power laser reflecting mirror according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional cooling device for a high-power laser reflection mirror.

FIG. 4 is a cross-sectional view showing another conventional cooling device for a high-power laser reflection mirror.

5 is a rear view showing the back surface of the high-power laser reflection mirror of FIG. 4;

[Explanation of symbols]

 1 Metal Mirror 1b Back Side of Metal Mirror 5 Cooling Groove 7 Temperature Sensor 8 Filling Material 14 Discharge Hole 15 Cover Member 16 Seal Screw R Refrigerant

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Ushida 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72) Inventor Shozo Watabe 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Company Nikon

Claims (4)

[Claims] 1. A back surface of a reflection mirror for a high-power laser is covered with a cover member to form a coolant channel between the back surface of the reflection mirror and the cover member, and a coolant is circulated in the coolant channel. In a cooling device for a reflection mirror for a high-power laser, which suppresses a temperature rise of the reflection mirror due to absorption of laser light, the rigidity of the cover member is lower than the rigidity of the reflection mirror for the high-power laser. Cooling device for reflective mirrors. 2. A screw for connecting the reflection mirror and the cover member is provided in the vicinity of a coolant supply port formed in the cover member for supplying the coolant to the coolant channel. The cooling device for a high-power laser reflection mirror according to claim 1. 3. A temperature detecting means for detecting the temperature of the reflection mirror for high power laser, and a reflection mirror for high power laser by adjusting the flow rate or temperature of the refrigerant based on a detection signal from the temperature detection means. 3. The cooling device for a high-power laser reflection mirror according to claim 1, further comprising a control means for controlling the temperature of the. 4. A cooling device for a high-power laser reflection mirror, wherein a coolant is circulated on the back surface of the high-power laser reflection mirror to suppress the temperature rise of the reflection mirror due to laser light absorption. A temperature detection means for detecting the temperature of the mirror; and a control means for controlling the temperature of the high-power laser reflection mirror by adjusting the flow rate or temperature of the refrigerant based on the detection signal from the temperature detection means. A cooling device for a high-power laser reflection mirror.