CN111326940A

CN111326940A - Gas laser device

Info

Publication number: CN111326940A
Application number: CN201911087507.4A
Authority: CN
Inventors: 冈田康弘; 万雅史; 田中研太; 河村让一
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2018-12-14
Filing date: 2019-11-08
Publication date: 2020-06-23
Also published as: KR20200073986A; JP7359540B2; JP2020096139A; TW202025580A; TWM637550U

Abstract

The invention provides a gas laser device which can restrain the deterioration of optical components such as a reflector caused by particles without arranging a special device for removing the particles in a chamber. An optical resonator for confining laser light is disposed in a chamber filled with a laser gas. In the height direction, an introduction port for introducing the 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. Laser gas is exhausted from the chamber via an exhaust port.

Description

Gas laser device

The present application claims priority based on japanese patent application No. 2018-234717, filed 12, 14, 2018. The entire contents of this Japanese application are incorporated by reference into this specification.

Technical Field

The present invention relates to a gas laser apparatus.

Background

If particles in the chamber of the gas laser apparatus adhere to the surface of the mirror of the optical resonator, the mirror may be deteriorated due to sintering of the particles. These particles enter the chamber when the chamber is opened, for example, in assembly or maintenance of the gas laser apparatus, or the like. Particles entering the chamber do not exit the chamber and stay in the chamber.

Patent document 1 listed below discloses a gas laser device in which a dust trap device is disposed in a chamber. By causing the dust trapping device to trap the fine particles in the chamber, deterioration of the mirror can be suppressed.

Patent document 1: japanese examined patent publication (Kokoku) No. 2-17491

In the conventional gas laser apparatus, a space for accommodating the dust trap apparatus needs to be prepared in the chamber. Therefore, the chamber becomes large. Further, depending on the position where the dust capture device is installed, the dust capture device may cause a decrease in the laser gas flow rate.

Disclosure of Invention

The invention aims to provide a gas laser device which can restrain the deterioration of optical components such as a reflector caused by particles without arranging a special device for removing the particles in a chamber.

According to an aspect of the present invention, there is provided a gas laser apparatus including:

a chamber filled with laser gas;

an optical resonator configured within the chamber and enclosing a laser;

an introduction port provided in a height direction at a position within or higher than a range in which the optical resonator is arranged, and configured to introduce a laser gas into the chamber; and

an exhaust port for exhausting laser gas from the chamber.

According to another aspect of the present invention, there is provided a gas laser apparatus comprising:

a chamber filled with laser gas;

an optical resonator configured within the chamber and enclosing a laser;

an introduction port for introducing laser gas into the chamber; and

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

When the introduction port is provided within the range in which the optical resonator is arranged or at a position higher than the range in which the optical resonator is arranged, a gas flow that flows downward through the space in which the optical resonator is arranged is formed when the laser gas is introduced into the chamber. With this gas flow, the particles will collect in the lower region of the chamber.

If the exhaust port is provided at a position lower than the introduction port, a gas flow flowing downward is formed both when the gas is discharged and when the gas is introduced, in a height range between the introduction port and the exhaust port. Therefore, the particles in the chamber can be efficiently collected to the lower region of the chamber.

By concentrating the particles to a low region of the chamber, the density of particles floating in the vicinity of the optical resonator can be reduced. As a result, deterioration of the optical components such as the mirrors of the optical resonator can be suppressed.

Drawings

Fig. 1 is a vertical cross-sectional view including an optical axis of a gas laser apparatus according to an embodiment.

Fig. 2 is a cross-sectional view of the gas laser apparatus according to the present embodiment, the cross-sectional view being perpendicular to the optical axis.

Fig. 3 is a flowchart showing a procedure of replacing the laser gas.

Fig. 4 is a sectional view of the gas laser apparatus during the period when the inside of the chamber is exhausted (step S2).

Fig. 5 is a sectional view of the gas laser apparatus during the period when the laser gas is introduced into the chamber (step S4).

Fig. 6 is a schematic diagram showing a positional relationship among an inlet port, an exhaust port, an optical resonator, and a blower of a gas laser apparatus according to another embodiment.

In the figure: 10-chamber, 11-optical chamber, 12-blower chamber, 13-upper and lower partition plates, 13A, 13B-opening, 14-bottom plate, 15-partition plate, 16-chamber support member, 21-discharge electrode, 22, 23-discharge electrode support, 24-discharge region, 25-optical resonator, 25M-optical resonator mirror, 26-common support, 27-optical resonator support, 28-optical transmission window, 31-inlet port, 32-inlet valve, 33-laser gas supply, 35-outlet port, 36-outlet valve, 37-vacuum pump, 50-blower, 51-1 st gas flow path, 52-2 nd gas flow path, 56-heat exchanger, 58-particle.

Detailed Description

A gas laser apparatus according to an embodiment will be described with reference to fig. 1 to 5.

Fig. 1 is a vertical cross-sectional view including an optical axis of a gas laser apparatus according to an embodiment. Here, an xyz rectangular coordinate system is defined in which the optical axis direction of the optical resonator is the z-axis direction and the vertical direction upper side is the x-axis direction. The gas laser device according to the embodiment is, for example, a carbon dioxide laser device.

The laser gas is contained within the chamber 10. Examples of the laser gas include carbon dioxide, nitrogen, and helium. The internal space of the chamber 10 is divided into an optical chamber 11 located on the upper side and a blower chamber 12 located on the lower side. The optical chamber 11 and the blower chamber 12 are partitioned by an upper partition plate 13 and a lower partition plate 13. 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 protrudes from the side wall of the blower chamber 12 toward both sides in the z-axis direction, and the length in the z-axis direction of the optical chamber 11 is longer than the length in the z-axis direction of the blower chamber 12. The chamber 10 is supported on the optical base by a chamber support member 16 at the bottom plate 14 of the optical chamber 11.

A pair of discharge electrodes 21 are disposed in the optical chamber 11. The pair of discharge electrodes 21 are supported on the base plate 14 via discharge

electrode supporting members

22 and 23, respectively. The pair of discharge electrodes 21 are disposed with a gap therebetween in the x-axis direction, and define a discharge region 24 therebetween. The discharge electrode 21 generates a discharge in the discharge region 24, thereby exciting the laser gas. As will be described later with reference to fig. 2, the laser gas flows through the discharge region 24 in a direction perpendicular to the paper surface of fig. 1.

An optical resonator 25 is supported on a common support member 26 disposed in the optical chamber 11. The optical resonator 25 is constituted by a pair of mirrors 25M, for example. The optical axis of the optical cavity 25 passes through the discharge region 24, and the optical cavity 25 encloses the laser light. The common support member 26 is supported by the base plate 14 via an optical resonator support member 27. A light transmission window 28 through which a laser beam passes is attached to a portion where an extended line extending from the optical axis of the optical resonator 25 toward one mirror 25M (left side mirror in fig. 1) intersects with the wall surface of the optical chamber 11. The laser beam excited in the optical resonator 25 is radiated toward the outside through the light transmitting window 28.

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

An introduction port 31 for introducing the laser gas into the chamber 10 is provided in a wall surface of the optical chamber 11. The introduction port 31 is connected to a laser gas supply source 33 via an introduction valve 32. When the introduction valve 32 is opened, the 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 where the optical resonator 25 is arranged in the height direction.

An exhaust port 35 for discharging the laser gas from the chamber 10 is provided in a wall surface of the blower chamber 12. The exhaust port 35 is connected to a vacuum pump 37 via an 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 a range where the blower 50 is arranged in the height direction.

The positions of the introduction port 31 and the exhaust port 35 in the horizontal direction are not specifically shown in fig. 1. For example, the introduction port 31 and the exhaust port 35 do not necessarily have to be disposed on a vertical cross section including the optical axis of the optical resonator 25. Therefore, the introduction port 31 and the exhaust port 35 may not be shown in the cross section shown in fig. 1. Although fig. 1 shows the case where 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, the introduction port 31 and the exhaust port 35 may be provided on another wall surface, for example, a wall surface parallel to the optical axis.

Fig. 2 is a cross-sectional view of the gas laser apparatus according to the present embodiment, the cross-sectional view being perpendicular to the optical axis (z-axis). The internal space of the chamber 10 is partitioned into an upper optical chamber 11 and a lower blower chamber 12 by an upper partition plate 13 and a lower partition plate 13. A pair of discharge electrodes 21 and a common support member 26 for supporting the optical resonator 25 are disposed in the optical chamber 11. A 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 the discharge region 24.

A partition 15 is disposed in the optical chamber 11. The separators 15 define a 1 st gas flow path 51 from the opening 13A provided in the upper and lower separators 13 to the discharge region 24, and a 2 nd gas flow path 52 from the discharge region 24 to the other opening 13B provided in the upper and lower separators 13. 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). The blower chamber 12, the 1 st gas passage 51, the discharge region 24, and the 2 nd gas passage 52 constitute a circulation passage through which the laser gas circulates. The blower 50 generates a laser gas flow to circulate the laser gas in the circulation flow path. The flow path cross section of the circulation flow path in the blower chamber 12 is larger than the flow path cross section of the circulation flow path in the optical chamber 11.

A heat exchanger 56 is accommodated in the circulation flow path in the blower chamber 12. The laser gas heated in the discharge region 24 is cooled by the heat exchanger 56, and the cooled laser gas is supplied to the discharge region 24 again.

The wall surface of the optical chamber 11 is provided with an introduction port 31, and the wall surface of the blower chamber 12 is provided with an exhaust port 35. As shown in fig. 1, the introduction port 31 is disposed at a position higher than the optical resonator 25. The exhaust port 35 is disposed at a position lower than the blower 50. In addition, as in the case of fig. 1, the positions of the introduction port 31 and the exhaust port 35 in the horizontal direction are not specifically shown in fig. 2. The introduction port 31 and the exhaust port 35 may be provided at any position on the wall surface of the chamber 10 in the horizontal direction.

Fig. 3 is a flowchart showing a procedure of replacing the laser gas.

During operation of the gas laser device, both the inlet valve 32 and the outlet valve 36 (fig. 1, 2) are closed. When the laser gas is replaced, the exhaust valve 36 is opened while maintaining the closed state of the introduction valve 32 (step S1). In this state, the vacuum pump 37 (fig. 1) is operated to exhaust the chamber 10 (step S2).

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

Fig. 4 is a sectional view of the gas laser apparatus during the period of exhausting the inside of the chamber 10 (step S2). In fig. 4, the laser gas flow during the laser gas discharge is indicated by arrows. Since the exhaust port 35 is disposed at a position lower than the blower 50, a laser gas flow flowing from above to below is generated in the chamber 10. Thereby, the particles floating in the laser gas move toward the lower side of the chamber 10. As a result, a large amount of particles 58 accumulate on the bottom surface of the chamber 10.

Fig. 5 is a sectional view of the gas laser apparatus during the period when the laser gas is introduced into the chamber 10 (step S4). In fig. 5, (a) and (B), laser gas flows during the introduction of the laser gas are indicated by arrows. Since the introduction port 31 is disposed at a position higher than the optical resonator 25, the laser gas is introduced into the space where the optical resonator 25 is disposed, thereby generating a laser gas flow flowing downward from the space where the optical resonator 25 is disposed. The particles 58 floating in the space where the optical resonator 25 is arranged move downward with the laser gas flow. As a result, a large amount of particles 58 accumulate on the bottom surface of the chamber 10.

Next, the excellent effects of the present embodiment will be described.

In the present embodiment, when the laser gas is discharged from the chamber 10 (step S2), as shown in fig. 4, a large number of particles 58 floating in the chamber 10 are deposited on the bottom surface of the chamber 10. When the laser gas is introduced into the chamber 10 (step S4), many particles 58 floating in the chamber 10 are also deposited on the bottom surface of the chamber 10 as shown in fig. 5.

When the laser gas is circulated in the operation of the gas laser apparatus, the flow rate near the bottom surface of the chamber 10 is slower than that in other regions. Therefore, the particles 58 accumulated on the bottom surface of the chamber 10 are less likely to be rolled up during the circulation of the laser gas and to be re-floated in the chamber 10. Therefore, the number of particles floating in the chamber 10 can be reduced.

Next, a preferred positional relationship between the optical resonator 25 and the blower 50 (fig. 1 and 2) will be described. During laser oscillation, the mirror 25M (fig. 1) of the optical resonator 25 is heated to a high temperature. If the particles 58 adhere to the mirror 25M, the particles 58 may be sintered to the mirror 25M when a high temperature is reached. It is preferable to reduce the density of the particles 58 in the internal space of the chamber 10, particularly in the space where the optical resonance cavity 25 is arranged, which is liable to reach a high temperature. The particles 58 move downward in the chamber 10 due to gravity, and therefore, the optical resonance cavity 25 is preferably disposed at a higher position than the blower 50.

Next, a preferred height at which the introduction port 31 and the exhaust port 35 (fig. 1 and 2) are arranged will be described.

As shown in fig. 4, during the discharge of the laser gas, a gas flow toward the discharge port 35 is formed in the chamber 10. As shown in fig. 5, during the introduction of the laser gas, a gas flow is formed which diffuses from the introduction port 31 into the chamber 10. In the height direction, a gas flow from the height of the introduction port 31 to the height of the exhaust port 35 is formed in the space between the exhaust port 35 and the introduction port 31, regardless of whether in the gas exhaust or in the gas introduction. In order to move the particles 58 downward in the chamber 10, it is preferable that the gas flow formed in the space between the exhaust port 35 and the introduction port 31 flows downward. In order to form such a gas flow, the introduction port 31 is preferably disposed at a higher position than the exhaust port 35.

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

In order to remove the particles 58 in the space where the optical resonator 25 is arranged, it is preferable that the laser gas introduced into the chamber 10 flows downward after passing through the space where the optical resonator 25 is arranged during the introduction of the laser gas. In order to form such a gas flow, it is preferable that the introduction port 31 is disposed at a position higher than the range where the optical resonator 25 is disposed in the height direction.

When the laser gas is introduced into the chamber 10 after vacuum evacuation from the introduction port 31, a gas flow having a high flow rate is formed in the vicinity of the introduction port 31, and the flow rate decreases as the flow rate moves away from the introduction port 31. In order to effectively remove the particles 58 from the space where the optical resonator 25 is arranged, it is preferable that the laser gas introduced into the chamber 10 maintain a high flow rate while passing through the space where the optical resonator 25 is arranged. In order to form such a gas flow, it is preferable to shorten the distance from the introduction port 31 to the optical resonator 25. For example, the distance from the introduction port 31 to the optical resonator 25 is preferably shorter than the distance from the exhaust port 35 to the optical resonator 25.

Next, another embodiment will be described with reference to fig. 6. Hereinafter, the same structure as that of the gas laser apparatus according to the embodiment shown in fig. 1 to 5 will not be described. Fig. 6 is a schematic diagram showing a positional relationship among the inlet port 31, the exhaust port 35, the optical resonator 25, and the blower 50 of the gas laser apparatus according to another embodiment.

In the embodiment shown in fig. 6 (a), the introduction port 31 is arranged within the range where the optical resonator 25 is arranged in the height direction. At this time, the laser gas introduced into the chamber 10 from the introduction port 31 passes through the space where the optical resonator 25 is disposed while maintaining a high flow rate. Then, the laser gas flows downward.

In the embodiment shown in fig. 6 (B), the exhaust port 35 is disposed at a position lower than the optical resonance cavity 25 and higher than the blower 50. Similarly to the embodiment shown in fig. 1 and 2, the introduction port 31 is disposed at a position higher than the optical resonator 25. At this time, in the space where the optical resonator 25 is disposed, a gas flow flowing downward is generated both at the time of discharging the gas and at the time of introducing the gas. In the space where the blower 50 is disposed, a gas flow that flows upward is formed when the gas is discharged, and a gas flow that flows downward is formed when the gas is introduced later. Therefore, the particles floating in the chamber 10 are collected to the bottom surface of the chamber 10 when the gas is introduced.

In the embodiment shown in fig. 6 (C), the introduction port 31 is disposed at a position lower than the optical resonator 25. Similarly to the embodiment shown in fig. 1 and 2, the exhaust port 35 is disposed at a position lower than the introduction port 31 and the blower 50. In this case, the effect of collecting the fine particles floating in the chamber 10 on the bottom surface of the chamber 10 at the time of gas discharge can also be obtained.

In the embodiment shown in fig. 6 (D), the exhaust port 35 is disposed at substantially the same height as the introduction port 31. At this time, a gas flow mainly flowing upward is formed when the gas is discharged, but a gas flow flowing downward through the space where the optical resonator 25 is arranged is formed when the gas is introduced, as in the embodiment shown in fig. 1 and 2. Therefore, the particles floating in the chamber 10 after the gas is discharged are collected to the bottom surface of the chamber 10 when the gas is introduced.

As described above, in the embodiments shown in (a) to (D) in fig. 6, the particles floating in the chamber 10 can be gathered downward, so that the density of the particles floating in the space in the vicinity of the optical resonance cavity 25 can be reduced. As a result, deterioration of the mirror 25M of the optical resonator 25 can be suppressed. In addition, when optical components other than the reflecting mirror are disposed in the chamber 10, deterioration of these optical components due to particles can be suppressed.

The above embodiments are merely examples, and it is needless to say that structures shown in different embodiments may be partially replaced or combined. The same operational effects of the same structure in the plurality of embodiments are not described one by one in each embodiment. The present invention is not limited to the above-described embodiments. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made to the present invention.

Claims

1. A gas laser device is characterized by comprising:

a chamber filled with laser gas;

an optical resonator configured within the chamber and enclosing a laser;

an exhaust port for exhausting laser gas from the chamber.

2. A gas laser device is characterized by comprising:

a chamber filled with laser gas;

an optical resonator configured within the chamber and enclosing a laser;

an introduction port for introducing laser gas into the chamber; and

3. The gas laser apparatus according to claim 1 or 2,

there is also a blower disposed within the chamber at a lower position than the optical resonator.

4. The gas laser apparatus according to claim 3,

the exhaust port is disposed at a lower position than the blower.

5. The gas laser apparatus according to any one of claims 1 to 4,

the distance from the introduction port to the optical resonator is shorter than the distance from the exhaust port to the optical resonator.