KR20200073986A - Gas laser apparatus - Google Patents

Abstract

Provided is a gas laser apparatus capable of suppressing the degradation of an optical component such as a mirror or the like due to particles without having to arrange a dedicated device for removing particles in a chamber. In a chamber filled with laser gas, an optical resonator is disposed to confine laser light. With respect to a height direction, an introduction port for introducing laser gas into the chamber is provided within a range in which the optical resonator is arranged or at a position higher than the range in which the optical resonator is arranged. The laser gas is exhausted from the chamber through an exhaust port.

Description

Gas laser system {GAS LASER APPARATUS}

This application claims priority based on Japanese Patent Application No. 2018-234717 filed on December 14, 2018. The entire contents of the application are incorporated herein by reference.

The present invention relates to a gas laser device.

When particles in the chamber of the gas laser device adhere to the surface of the mirror of the optical resonator, the mirror deteriorates due to sticking (sticking) or the like. These particles enter the chamber when the chamber is opened, for example, in assembly or maintenance of a gas laser device. Particles entering the chamber do not escape from the chamber and remain in the chamber.

In the following Patent Document 1, a gas laser device in which a dust trapping device is disposed in a chamber is disclosed. When the dust trapping device captures particles in the chamber, deterioration of the mirror is suppressed.

Patent Literature 1: Japanese Publication Utility Model Publication No. Hei 2-17491

In a conventional gas laser device, a space for accommodating a dust trap device in a chamber must be prepared. For this reason, the chamber is enlarged. Further, depending on the place where the dust trapping device is installed, the dust trapping device may cause a decrease in the flow rate of the laser gas. An object of the present invention is to provide a gas ray storage value capable of suppressing deterioration of optical components such as mirrors caused by particles, even without a dedicated device for removing particles in the chamber.

According to one aspect of the invention,

A chamber filled with laser gas,

An optical resonator disposed in the chamber and trapping laser light,

With respect to the height direction, it is provided in a position higher than the range in which the optical resonator is disposed, or the range in which the optical resonator is disposed, and an introduction port for introducing laser gas into the chamber,

A gas laser apparatus having an exhaust port for exhausting laser gas from within the chamber is provided.

According to another aspect of the invention,

A chamber filled with laser gas,

An optical resonator disposed in the chamber and trapping laser light,

An introduction port for introducing laser gas into the chamber,

A gas laser device provided at a position lower than the introduction port and having an exhaust port for exhausting laser gas from the chamber is provided.

When the introduction port is provided in a position within the range where the optical resonator is disposed or higher than the range where the optical resonator is disposed, when introducing the laser gas into the chamber, the gas passes through the space where the optical resonator is disposed and goes downward. Flow is formed. Riding this gas stream, particles collect in the lower area of the chamber.

Moreover, when the exhaust port is provided at a position lower than the introduction port, gas flows downward at both the time of exhaust and introduction of the gas in the height range between the introduction port and the exhaust port. For this reason, particles in the chamber can be efficiently collected in the lower region of the chamber.

By collecting particles in the lower region of the chamber, the density of particles floating near the optical resonator can be reduced. As a result, deterioration of optical components such as a mirror of the optical resonator can be suppressed.

1 is a vertical cross-sectional view including an optical axis of a gas laser device according to an embodiment.
2 is a cross-sectional view perpendicular to the optical axis of the gas laser device according to the present embodiment.
3 is a flowchart showing the procedure for exchanging laser gas.
4 is a cross-sectional view of the gas laser device during a period in which the chamber is exhausted (step S2).
5(a) and 5(b) are cross-sectional views of a gas laser device during a period in which laser gas is introduced into the chamber (step S4).
6A to 6D are schematic diagrams showing the positional relationship of the introduction port, the exhaust port, the optical resonator, and the blower of the gas laser device according to another embodiment.

The gas laser device according to the embodiment will be described with reference to FIGS. 1 to 5.

1 is a vertical cross-sectional view including an optical axis of a gas laser device according to an embodiment. An xyz rectangular coordinate system is defined with the optical axis direction of the optical resonator as the z-axis direction and the vertical upward direction as the x-axis direction. The gas ray storage value according to the embodiment is, for example, a carbon dioxide gas laser device.

The laser gas is accommodated in the chamber 10. The laser gas includes, for example, carbon dioxide, nitrogen, and helium. The interior space of the chamber 10 is divided into an optical chamber 11 positioned relatively upward and a blower chamber 12 positioned relatively lower. The optical chamber 11 and the blower chamber 12 are divided into upper and lower partition plates 13. However, the upper and lower partition plates 13 are provided with openings through which laser gas flows between the optical chamber 11 and the blower chamber 12. The bottom plate 14 of the optical chamber 11 extends from both side walls of the blower chamber 12 to both sides in the z-axis direction, and the length in the z-axis direction of the optical chamber 11 is z-axis of the blower chamber 12 It is longer than the length of the direction. The chamber 10 is supported on the optical base by the chamber support member 16 on the bottom plate 14 of the optical chamber 11.

In the optical chamber 11, a pair of discharge electrodes 21 are arranged. The pair of discharge electrodes 21 are supported on the bottom plate 14 through discharge electrode support members 22 and 23, respectively. The pair of discharge electrodes 21 are arranged at intervals in the x-axis direction, and a discharge region 24 is defined between them. The discharge electrode 21 excites the laser gas by generating discharge in the discharge region 24. As will be described later with reference to FIG. 2, the laser gas flows in the direction perpendicular to the ground of FIG. 1.

The optical resonator 25 is supported by the common support member 26 disposed in the optical chamber 11. The optical resonator 25 is composed of, for example, a pair of mirrors 25M. The optical axis of the optical resonator 25 passes through the discharge region 24, and the optical resonator 25 traps the laser light. The common support member 26 is supported by the bottom plate 14 through the optical resonator support member 27. An optical transmission window that transmits a laser beam at an intersection between an extension line extending the optical axis of the optical resonator 25 on one side of the mirror 25M (the mirror on the left side in FIG. 1) and the wall surface of the optical chamber 11. 28 is mounted. The laser beam excited in the optical resonator 25 passes through the light transmitting window 28 and is radiated to the outside.

The blower 50 is disposed in the blower chamber 12. That is, the optical resonator 25 and the discharge electrode 21 are disposed at a higher position than the blower 50. The blower 50 circulates the laser gas between the optical chamber 11 and the blower chamber 12.

On the wall surface of the optical chamber 11, an introduction port 31 for introducing laser gas into the chamber 10 is provided. The introduction port 31 is connected to the laser gas supply source 33 through the introduction valve 32. When the introduction valve 32 is opened, laser gas is introduced into the chamber 10 from the introduction port 31. The introduction port 31 is provided at a position higher than the range in which the optical resonator 25 is disposed with respect to the height direction.

On the wall surface of the blower chamber 12, an exhaust port 35 for exhausting laser gas from inside the chamber 10 is provided. The exhaust port 35 is connected to the vacuum pump 37 through the exhaust valve 36. When the exhaust valve 36 is opened and the vacuum pump 37 is operated, the chamber 10 is evacuated. The exhaust port 35 is provided at a position lower than the range in which the blower 50 is disposed with respect to the height direction.

1 does not specifically show the positions of the introduction port 31 and the exhaust port 35 in the horizontal direction. For example, the introduction port 31 and the exhaust port 35 need not be arranged on the vertical cross section including the optical axis of the optical resonator 25. Therefore, the introduction port 31 and the exhaust port 35 may not appear in the cross section shown in FIG. 1. In FIG. 1, although the introduction port 31 and the exhaust port 35 are provided on the wall surface perpendicular to the optical axis of the optical resonator 25, other wall surfaces, for example, provided on the wall surface parallel to the optical axis May be

2 is a cross-sectional view perpendicular to the optical axis (z-axis) of the gas laser device according to the present embodiment. The inner space of the chamber 10 is divided into an upper optical chamber 11 and a lower blower chamber 12 by the upper and lower partition plates 13. In the optical chamber 11, a common support member 26 for supporting a pair of discharge electrodes 21 and a photoresonator 25 is disposed. The discharge region 24 is defined between the discharge electrodes 21. A mirror 25M (FIG. 1) of the optical resonator 25 is disposed at a position overlapping with the discharge region 24.

A partition plate 15 is disposed in the optical chamber 11. The partition plate 15 is a first gas flow path 51 from the opening 13A provided in the upper and lower partition plates 13 to the discharge region 24, and the other provided in the upper and lower partition plates 13 from the discharge region 24. The second gas flow path 52 up to the opening 13B is defined. The laser gas flows through the discharge region 24 in a direction orthogonal to the optical axis (y-axis direction). The discharge direction (x-axis direction) is orthogonal to both the direction in which the laser gas flows (y-axis direction) and the optical axis direction (z-axis direction). A circulation path through which laser gas circulates is formed by the blower chamber 12, the first gas flow path 51, the discharge region 24, and the second gas flow path 52. The blower 50 generates a flow of laser gas so that the laser gas circulates through the circulation path. The flow path cross-section of the circulation path in the blower chamber 12 is larger than the flow path cross-section of the circulation path in the optical chamber 11.

The heat exchanger 56 is accommodated in the circulation path in the blower chamber 12. The laser gas heated in the discharge region 24 is cooled by passing through the heat exchanger 56, and the cooled laser gas is re-supplied to the discharge region 24.

The introduction port 31 is provided on the wall surface of the optical chamber 11, and the exhaust port 35 is provided on the wall surface of the blower chamber 12. As described with reference to FIG. 1, the introduction port 31 is disposed at a higher position than the optical resonator 25. The exhaust port 35 is disposed at a lower position than the blower 50. However, as in the case of Fig. 1, Fig. 2 does not specifically show the positions of the introduction port 31 and the exhaust port 35 in the horizontal direction. The introduction port 31 and the exhaust port 35 may be provided at any position on the wall surface of the chamber 10 with respect to the horizontal direction.

3 is a flowchart showing the procedure for exchanging laser gas.

During the period of operation of the gas ray storage value, the inlet valve 32 and the exhaust valve 36 (FIGS. 1 and 2) are closed. When exchanging laser gas, the introduction valve 32 remains closed, and the exhaust valve 36 is opened (step S1). By operating the vacuum pump 37 (FIG. 1) in this state, the inside of the chamber 10 is exhausted (step S2).

When the exhaust of the laser gas is finished, the exhaust valve 36 is closed and the introduction valve 32 is opened (step S3). Thereby, laser gas is introduced into the chamber 10 from the introduction port 31 (step S4). When the required amount of laser gas is introduced, the introduction valve 32 is closed (step S5).

4 is a cross-sectional view of the gas laser device during a period in which the chamber 10 is exhausted (step S2). In Fig. 4, the flow of laser gas in the laser gas exhaust is indicated by arrows. Since the exhaust port 35 is disposed at a lower position than the blower 50, a flow of laser gas from the top to the bottom is generated in the chamber 10. As a result, particles floating in the laser gas move toward the lower side of the chamber 10. As a result, many particles 58 are deposited on the bottom surface of the chamber 10.

5A and 5B are cross-sectional views of the gas laser device during a period (step S4) in which laser gas is introduced into the chamber 10. 5A and 5B, the flow of laser gas during laser gas introduction is indicated by arrows. Since the introduction port 31 is disposed at a higher position than the photoresonator 25, laser gas is introduced into the space in which the photoresonator 25 is disposed, and the laser directed downward from the space in which the photoresonator 25 is disposed. Gas flow occurs. The particles 58 floating in the space in which the optical resonator 25 is disposed move downward by the flow of laser gas. As a result, many particles 58 are deposited on the bottom surface of the chamber 10.

Next, the excellent effect of this embodiment will be described.

In this embodiment, when the laser gas is exhausted from the chamber 10 (step S2), as shown in Fig. 4, most of the particles 58 suspended in the chamber 10 are the bottom surface of the chamber 10. To be deposited. Also, when introducing laser gas into the chamber 10 (step S4), as described with reference to FIGS. 5A and 5B, most of the particles 58 suspended in the chamber 10 are chamber 10. Is deposited on the bottom surface.

When the laser gas is circulated during the operation of the gas laser device, the flow velocity in the vicinity of the bottom surface of the chamber 10 is slower than the flow velocity in other regions. For this reason, there is a low possibility that the particles 58 deposited on the bottom surface of the chamber 10 are swept up during the circulation of the laser gas and resuspended in the chamber 10. Therefore, the number of particles floating in the chamber 10 can be reduced.

Next, a preferable positional relationship between the optical resonator 25 and the blower 50 (FIGS. 1 and 2) will be described. During laser oscillation, the mirror 25M of the optical resonator 25 (FIG. 1) is heated to a high temperature. If the particles 58 are attached to the mirror 25M, the particles 58 will stick to the mirror 25M when the temperature becomes high. In the interior space of the chamber 10, it is preferable to lower the density of the particles 58 in the space where the optical resonator 25, which is particularly prone to high temperature, is disposed. Since the particle 58 moves downward in the chamber 10 by the action of gravity, it is preferable to arrange the photoresonator 25 at a position higher than the blower 50.

Next, a preferable height in which the introduction port 31 and the exhaust port 35 (FIGS. 1 and 2) are arranged will be described.

As shown in Fig. 4, during the exhaust of the laser gas, a gas flow toward the exhaust port 35 is formed in the chamber 10. During the introduction of the laser gas, as shown in FIGS. 5A and 5B, a gas flow diffused into the chamber 10 from the introduction port 31 is formed. With respect to the height direction, the space between the exhaust port 35 and the introduction port 31 is directed to the height of the exhaust port 35 from the height of the introduction port 31, either during gas exhaust or gas introduction. Gas flow is formed. In order to move the particles 58 toward the lower side of the chamber 10, it is preferable that the gas flow formed in the space between the exhaust port 35 and the introduction port 31 is directed downward. In order to form such a gas stream, it is preferable to arrange the introduction port 31 at a position higher than the exhaust port 35.

In order to collect the particles 58 on the bottom surface of the chamber 10 during the exhaust of the laser gas, it is preferable to form a downward gas flow in most of the chamber 10. In order to form such a gas flow, it is preferable to arrange the exhaust port 35 at a lower position than the blower 50.

Further, in order to remove the particles 58 in the space in which the optical resonator 25 is disposed, during the introduction of the laser gas, the laser gas introduced into the chamber 10 passes through the space in which the optical resonator 25 is disposed. After that, it is preferable to make it flow downward. In order to form such a gas flow, it is preferable to arrange the introduction port 31 in a position higher than the range in which the optical resonator 25 is disposed, with respect to the height direction.

When the laser gas is introduced from the introduction port 31 into the vacuum-exhausted chamber 10, a gas flow with a large flow rate is formed in the vicinity of the introduction port 31, and the flow rate decreases as it moves away from the introduction port 31. . In order to efficiently remove the particles 58 from the space where the optical resonator 25 is disposed, a rapid flow velocity is maintained when the laser gas introduced into the chamber 10 passes through the space where the optical resonator 25 is disposed. It is desirable to do. In order to form such a gas stream, it is desirable to shorten the distance from the introduction port 31 to the optical resonator 25. As an example, it is preferable to make the distance from the introduction port 31 to the optical resonator 25 shorter than the distance from the exhaust port 35 to the optical resonator 25.

Next, another embodiment will be described with reference to Figs. 6A to 6D. Hereinafter, description will be omitted of the configuration common to the gas laser apparatus according to the embodiment shown in FIGS. 1 to 5B. 6(a) to 6(d) are schematic diagrams showing the positional relationship between the introduction port 31, the exhaust port 35, the optical resonator 25, and the blower 50 of the gas laser device according to another embodiment. to be.

In the embodiment shown in Fig. 6(a), the introduction port 31 is disposed within the range in which the optical resonator 25 is disposed with respect to the height direction. In this case, the laser gas introduced into the chamber 10 from the introduction port 31 maintains a fast flow rate and passes through the space of the optical resonator 25. Thereafter, the laser gas flows downward.

In the embodiment shown in Fig. 6B, the exhaust port 35 is disposed at a position lower than the light resonator 25 and higher than the blower 50. The introduction port 31 is disposed at a higher position than the optical resonator 25, similarly to the embodiment shown in FIGS. 1 and 2. In this case, in the space where the optical resonator 25 is disposed, gas flows downward in both the gas exhaust and gas introduction. In the space where the blower 50 is disposed, gas flows upward when gas is discharged, but gas flows downward when gas is introduced thereafter. For this reason, particles floating in the chamber 10 collect on the bottom surface of the chamber 10 when gas is introduced.

In the embodiment shown in Fig. 6(c), the introduction port 31 is disposed at a lower position than the optical resonator 25. The exhaust port 35 is arranged at a lower position than the introduction port 31 and the blower 50, similarly to the embodiment shown in FIGS. 1 and 2. Also in this case, the effect of collecting particles floating in the chamber 10 on the bottom surface of the chamber 10 during gas exhaust is obtained.

In the embodiment shown in Fig. 6(d), the exhaust port 35 is disposed at the same height as the introduction port 31. In this case, mainly gas upwards is formed at the time of gas exhaust, but when gas is introduced, as in the embodiment shown in Figs. 1 and 2, through the space in which the optical resonator 25 is arranged, it is directed downwards. Gas flow is formed. For this reason, particles floating in the chamber 10 after gas exhaust are collected on the bottom surface of the chamber 10 when gas is introduced.

As described above, in the embodiment shown in any one of (a) to (d) of FIG. 6, the particles floating in the chamber 10 are collected downward, and the density of floating the space in the vicinity of the optical resonator 25 is increased. Can be reduced. As a result, it becomes possible to suppress deterioration of the mirror 25M of the optical resonator 25. Moreover, when the optical components other than a mirror are arrange|positioned in the chamber 10, deterioration resulting from particles of these optical components can be suppressed.

It is needless to say that each of the above-described embodiments is an example, and partial substitution or combination of configurations shown in other embodiments is possible. The same operation and effect by the same configuration of the plurality of embodiments are not mentioned separately for each embodiment. In addition, the present invention is not limited to the above-described embodiment. For example, it will be apparent to those skilled in the art that various changes, improvements, combinations, and the like are possible.

10 chamber
11 Optical room
12 Blower Room
13 Upper and lower divisions
13A, 13B opening
14 bottom plate
15 compartments
16 chamber support member
21 discharge electrode
22, 23 discharge electrode support member
24 discharge area
25 light resonator
25M Optical Resonator Mirror
26 Common support member
27 Optical resonator support member
28 Light transmission window
31 Introduction port
32 Inlet valve
33 Laser gas supply source
35 Exhaust port
36 Exhaust valve
37 Vacuum pump
50 blowers
51 1st gas flow path
52 2nd gas flow path
56 heat exchanger
58 Particles

Claims (5)

A chamber filled with laser gas,
An optical resonator disposed in the chamber and trapping laser light,
With respect to the height direction, it is provided in a position higher than the range in which the optical resonator is disposed, or the range in which the optical resonator is disposed, and an introduction port for introducing laser gas into the chamber,
A gas laser device having an exhaust port for exhausting laser gas from within the chamber. A chamber filled with laser gas,
An optical resonator disposed in the chamber and trapping laser light,
An introduction port for introducing laser gas into the chamber,
A gas laser device provided at a position lower than the introduction port and having an exhaust port for exhausting laser gas from within the chamber. The method according to claim 1 or 2,
A gas laser apparatus having a blower disposed in a lower position of the chamber than the optical resonator. According to claim 3,
The exhaust port is a gas laser device disposed at a lower position than the blower. The method according to claim 1 or 2,
A gas laser device in which the distance from the introduction port to the optical resonator is shorter than the distance from the exhaust port to the optical resonator.

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