JPH0613679A - Gas laser - Google Patents

Abstract

PURPOSE:To provide a gas laser of high efficiency using dielectric electrodes. CONSTITUTION:A first dielectric electrode 12 and a second dielectric electrode 13 are opposed across a discharge space 14. The dielectric electrodes 12 and 13 comprise long electrode bodies 12a and 13a along the flow of gas (perpendicular to the Figure), and rectangular sheaths 12b and 13b covering the electrode bodies. Low-permittivity spaces 12e, 12f, 13e and 13f for reducing capacitive coupling are formed on opposite sides of the electrode bodies within the sheaths. When high-frequency voltage is applied between the electrode bodies 12a and 13a in this structure, the discharge is kept from spreading to their sides, and the efficiency of laser oscillation is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser oscillator that oscillates a laser beam by applying a high frequency voltage between electrodes to cause discharge, and in particular, by using a dielectric electrode, the power density in a discharge space is increased. The present invention relates to a gas laser oscillator designed for uniformization of the temperature.

[0002]

2. Description of the Related Art FIG. 13 shows a schematic structure of a laser oscillator of this type. In FIG. 13, the pair of dielectric electrodes 1 are arranged so as to face each other with the discharge space 2 in which the laser gas circulates in the direction indicated by the arrow A being sandwiched. The dielectric electrode 1 is configured by covering an electrode portion 3 having a long shape in a direction orthogonal to the laser gas flow (direction orthogonal to the paper surface) with an outer shell portion 4 made of a dielectric material. In the so-called cross-flow type laser oscillator configured as described above, when a high frequency voltage is applied between the electrode portions 3 from the high frequency power source 5, the laser gas flowing in the discharge space 2 is excited and the laser light is orthogonal to the paper surface. Occurs in the direction. In this case, since the outer shell portion 4 made of a dielectric material is present around the electrode portion 3, the discharge space 2
In this way, the power density becomes uniform, the uniform discharge can be formed, and the stable laser output can be obtained.

[0003]

In order to improve the laser oscillation efficiency, it is necessary to increase the frequency of the high frequency voltage applied between the electrode portions 3. However, when the output frequency of the high-frequency power source 5 is increased, discharge is generated on both sides of the electrode part 3 due to capacitive coupling through the outer shell part 4 made of a dielectric material provided so as to cover the electrode part 3. Unnecessarily, the result is that it is difficult to sufficiently improve the laser oscillation efficiency even though the output frequency of the high frequency power source 5 is increased, which may be contrary to the intended purpose in some cases. There is a possibility that the laser oscillation efficiency may be lowered.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas laser oscillator capable of improving laser oscillation efficiency while having a structure using a dielectric electrode. Especially.

[0005]

In order to achieve the above object, the present invention provides a discharge space in which a laser gas circulates through at least a pair of dielectric electrodes provided with an outer shell part made of a dielectric material around the electrode parts. In a gas laser oscillator arranged in a sandwiched state so that a high frequency voltage is applied between the electrode parts, a capacitive coupling suppressing part having a relative dielectric constant smaller than that of the outer shell part on both sides of the electrode part in the dielectric electrode. Is provided.

In this case, the capacitive coupling suppressing portion can be formed by a space portion formed by partitioning the inside of the outer shell portion made of the dielectric material with a partition wall.

Further, the outer shell may be partitioned by a partition wall to form an electrode housing chamber for housing the electrode portion, and the cooling medium may be circulated in the electrode housing chamber.

Further, in the case of forming the electrode accommodating chamber as described above, an air chamber adjacent to the electrode accommodating chamber via the seal member is formed in the outer shell part, and an end portion of the electrode part existing in the electrode accommodating chamber is formed. Can be configured to penetrate through the seal member to project into the air chamber, and when adopting such a configuration, the end portion of the electrode portion projected into the air chamber is It may be configured to be connected to a power supply lead wire.

In addition, after forming the outer shell into a container,
A structure in which a pipe-shaped electrode portion is additionally provided on the inner wall of the outer shell portion so that the space portion formed around the electrode portion functions as a capacitive coupling suppressing portion and a cooling medium is circulated in the electrode portion. Can also be

Further, the surface of the outer shell facing the discharge space may be formed in a flat shape along the flow of the laser gas in the discharge space.

Further, the distance between the capacitive coupling suppressing part and the surface of the dielectric outer shell facing the discharge space is d1, and the surface of the capacitive coupling suppressing part and the dielectric outer shell opposite to the discharge space. Is D2, the width of the capacitive coupling suppressing portion is W, the thickness of the dielectric outer shell portion at a portion corresponding to the electrode portion is D, and the relative permittivity of the dielectric outer shell portion is ε1. , D1 when the relative permittivity of the capacitive coupling suppressing section is ε2.
, D2, W, D, ε1 and ε2 are preferably configured such that the following relationship holds (provided that d1, d2,
Each unit of W and D is mm). d1 −11 ≦ − (ε2 / ε1) × 10 × D / 5 × (25-2 × d2) / W

[0012]

When a high-frequency voltage is applied between the electrode portions of the pair of dielectric electrodes, the laser gas circulating in the discharge space between the dielectric electrodes is excited to generate laser light. In this case, since the outer shell made of a dielectric material exists around the electrode portion, the power density in the discharge space becomes uniform. In addition, since there are capacitive coupling suppression parts on both sides of the electrode part that have a smaller relative dielectric constant than the outer shell part, it is possible to prevent discharge from being dispersed to both sides of the electrode part even when a high frequency voltage is applied to the electrode part. As a result, the laser oscillation efficiency can be improved.

In the case where the capacitive coupling suppressing portion is constituted by a space portion, for example, the space portion is communicated with the atmosphere or an insulating gas is filled in the space portion so that the relative dielectric constant in that portion is extremely reduced. The capacitance can be made sufficiently small, and thus the capacitive coupling through the space can be made sufficiently small, and the effect of suppressing the dispersion of discharge can be further enhanced.

When the cooling medium is circulated in the electrode accommodating chamber for accommodating the electrode part, the temperature rise of the electrode part is suppressed, so that the electrode part and the outer shell part in the dielectric electrode are It is possible to prevent the occurrence of strain between the two due to the difference in the coefficient of thermal expansion between the two.

In the case where an air chamber adjacent to the electrode accommodating chamber is formed in the outer shell part through a seal member and the end of the electrode part is projected into this air chamber, the end part of the electrode part Since the capacitance to ground can be reduced, it is possible to prevent the occurrence of abnormal discharge at the end of the electrode portion, which has a shape that tends to cause electric field concentration.

When the end portion of the electrode portion protruding into the air chamber is connected to the power source lead wire in the air chamber, the ground capacitance of the lead wire can be lowered, and this portion can be reduced. It is possible to prevent abnormal discharge in the.

When a pipe-shaped electrode portion is attached to the inner wall of the outer shell portion formed in a container shape, the electrode portion can be used also as a flow passage for the cooling medium, so that the entire structure is improved. It can be simplified.

When the surface of the outer shell facing the discharge space of the laser gas is configured to have a flat shape along the flow of the laser gas, the laser gas flows smoothly in the discharge space and the stability of the discharge is improved. Will increase.

The dimensions related to the capacitive coupling restraint portion are set forth in claim 8.
In the case of the configuration as described in (1), the leakage discharge current in the capacitive coupling suppressing unit can be suppressed, and thus the discharge loss suppressing function can be maximized.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a vertical cross-sectional structure of a so-called lateral flow type gas laser oscillator in which the gas flow is orthogonal to the output optical axis. In FIG. 1, a first dielectric electrode 12 is disposed in the center of the upper part of a wind tunnel container 11 having a rectangular cross section so as to face the inside of the wind tunnel container 11. In this case, the first dielectric electrode 12 is provided. The lower surface of 12 is configured to have a planar shape that is flush with the inner surface of the wind tunnel container 11.

A second dielectric electrode 13 forming a pair with the first dielectric electrode 12 is arranged in the central portion of the wind tunnel container 11, and between the dielectric electrodes 12 and 13 in the arranged state. There is a discharge space 14 in the interior. In this case, the second dielectric electrode 13 is supported by the support members 15 and 16, and the upper surface thereof is the first dielectric electrode 12
It is configured to be parallel to the lower surface of and to have a planar shape that is flush with the support members 15 and 16.

A blower 17 for circulating the laser gas and a heat exchanger 18 for cooling the laser gas are arranged in the lower part of the wind tunnel container 11. The laser gas is sealed in the wind tunnel container 11 at a pressure of about 65 torr, is circulated in the direction of arrow B by the blower 17, and flows through the discharge space 14 and then the heat exchanger 1.
It is cooled by 8.

Now, the first dielectric electrode 12 and the second dielectric electrode 12
The specific configuration of the dielectric electrode 13 will be described with reference to FIG. 2 as well. Since they have the same configuration, only the first dielectric electrode 12 will be described below,
For the second dielectric electrode 13, the first dielectric electrode 12
The description will be omitted by attaching the same subscripts to the same portions as.

That is, the first dielectric electrode 12 has an electrode portion 12a having a rectangular cross section formed in a long shape in a direction orthogonal to the laser gas flow (direction orthogonal to the paper surface), and this electrode portion 12a. And a rectangular container-shaped outer shell 12b made of a dielectric material (for example, ceramics) provided so as to surround the. In this case, in the outer shell portion 12b, three space portions extending in the direction orthogonal to the laser gas flow are formed adjacent to each other by partitioning the inside by the partition walls 12c and 12d, and the space portion in the center has the above-mentioned structure. By inserting the electrode portion 12a, the left and right space portions are made into the outer shell portion 1
2b, the relative permittivity of which is smaller than that of the capacitive coupling suppressors 12e, 12
It is configured as f.

Incidentally, the capacitive coupling suppressing portions 12e, 12f, 13
The space forming e and 13f is made to communicate with the atmosphere, or by enclosing an insulating gas inside,
The relative permittivity in that portion is extremely reduced.

Therefore, as shown in FIG. 1, the electrode portions 12a of the first dielectric electrode 12 and the second dielectric electrode 13 are formed.
When a high-frequency voltage is applied from the high-frequency power source 19 between the first and the third portions 13a and 13a, the laser gas flowing in the discharge space 14 is excited and the laser light 20 is generated in the direction orthogonal to the paper surface.
In this case, since the outer shell portions 12b and 13b made of a dielectric material are present around the electrode portions 12a and 13a, the power density in the discharge space 14 can be made uniform, so that uniform discharge can be achieved. It can be formed and a stable laser output can be obtained.

In this case, on both sides of the electrode portions 12a and 13a, a capacitive coupling suppressing portion 12e having an extremely small relative dielectric constant,
Since 12f, 13e, and 13f are present, it is possible to prevent the discharge from being unnecessarily dispersed on both sides of the electrode portions 12a and 13a even under the condition where the high frequency voltage is applied as described above. Like As a result, loss due to unnecessary discharge can be suppressed, so that even if the output frequency of the high frequency power supply 19 is sufficiently increased, no problem will occur, and thus the laser oscillation efficiency can be improved.

By the way, the capacitive coupling suppressing sections 12e, 12
In order to effectively exert the above-mentioned discharge loss suppressing function of f, 13e, and 13f, it is important how to determine the dimensions of the capacitive coupling suppressing portions 12e, 12f, 13e, and 13f. Come on. Therefore, the inventor of the present application calculated by calculation how the discharge current distribution changes according to the shape of the dielectric electrode in order to obtain the optimum dimensions of the capacitive coupling suppressing portions 12e, 12f, 13e, 13f. . That is, FIGS. 4A, 4B, and 4C show typical examples of the discharge current distribution obtained as described above.
FIG. 4A shows a dielectric electrode X having no capacitive coupling suppression portion, and FIG. 4B shows a rectangular cross section (however, the corners are provided with a suitable radius considering structural strength). In the case of the dielectric electrode Y provided with the capacitive coupling suppressor y0, FIG. 4C shows the dielectric electrode Z provided with the capacitive coupling suppressor z0 having a circular cross section.
This is an example of the case. In this case, the distribution of the discharge current is represented by the size of a line segment extending perpendicularly from the surface of the dielectric outer shells x1, y1, z1 of the dielectric electrodes X, Y, Z facing the discharge space.

In the case of the example of FIG. 4A, it can be seen that the discharge current leaks out not only below the electrode x2 but also in the lateral position thereof. In addition, FIG.
In the case of the example of (c), it can be seen that the current distribution is lowered on the surface facing the discharge space corresponding to the capacitive coupling suppressing portions y0 and z0. However, the capacitive coupling suppression unit 12 in the present embodiment.
The ideal dimensions of e, 12f, 13e, and 13f can be obtained by calculating the current distribution as described above.

That is, suppose that alumina, which is the most general dielectric constant ε 1 = 10, is used as the dielectric material for the outer shell.
Assuming a gas with a relative permittivity ε 2 = 1 as the capacitive coupling suppression part, and assuming that the thickness of the outer shell made of dielectric material at the part corresponding to the electrode part is 5 mm, the dimensions used in the above calculation As parameters, the capacitive coupling suppression units y1 and z in FIG.
The distance d1 between 1 and the surface of the dielectric outer shells y1 and z1 facing the discharge space, the distance between the capacitive coupling suppressing portions y1 and z1 and the surface of the dielectric outer shells y1 and z1 opposite to the discharge space. The width W of d2 and the capacitive coupling suppressing portions y1 and z1 is adopted (however, each unit of d1, d2 and W is mm). Further, as an evaluation value of the current suppression effect, a leakage current value I0 at a position 15 mm away from the electrodes y2 and z2 on the side of the capacitive coupling suppression parts y1 and z1 is used (however, this current value I0 is the electrode part y2,
(It is expressed as a percentage ratio to the discharge current at the position corresponding to the center of z2). The leakage current value I0 at a position 15 mm away from the electrode portions y2 and z2 was used as the evaluation value within the range compatible with the laser beam diameter actually used.
This is because leakage of discharge current is allowed up to about 15 mm.

FIG. 5 shows a curve calculated by using the dimensions d1 and d2 as parameters with respect to the change state of the leakage current value I0 with respect to the width dimension W. When there is no capacitive coupling suppressor (corresponding to the state of FIG. 4A), the leakage current value I
0 is a zero intercept with respect to the horizontal axis indicating W in FIG. 5, which is about 16%. FIG. 6 shows the relationship between the dimensions W, d1 and d2 that makes the leakage current value I0 10% or less, which is a value that can be practically used, from FIG. When an approximate expression for the curve shown in FIG. 6 was obtained, the following expression was obtained.

D1 −11 ≦ − (25−2 × d2) / W However, in the process of calculating the above formula, alumina having a relative permittivity ε1 = 10 is assumed as the dielectric, and the capacity coupling suppressing part is Assuming a gas with a permittivity ε 2 = 1 and assuming that the thickness of the outer shell made of a dielectric material is 5 mm at the part corresponding to the electrode part, the relative permittivity differs from this assumed example. When using the one, the ratio (ε 2 / ε
1) It is necessary to multiply by × 10, and when the thickness of the outer shell made of dielectric material at the portion corresponding to the electrode portion is Dmm other than 5 mm, the right side of the formula is multiplied by D / 5. Must be,
Generally, the dimensions of each part will be determined using the following equation.

D1 −11 ≦ − (ε2 / ε1) × 10 × D / 5 × (25-2 × d2) / W ... Therefore, in the present embodiment, as shown in FIG. In the electrode 12, the relative permittivity ε1 of the dielectric material forming the outer shell portion 12b is "10", and the capacitive coupling suppressing portions 12e, 12
When the relative permittivity ε2 of f is set to “1” and the thickness D of the outer shell portion 12b at the portion corresponding to the electrode portion 12a is set to 5 mm (that is, (ε2 / ε1) × 10 = 1, D / 5 = 1
In this case, the capacitive coupling suppressing unit 12e,
The distance 12f from the surface of the dielectric outer shell 12b facing the discharge space 14 is d1, and the capacitive coupling suppressing portions 12e and 12f.
And the space between the discharge space 14 (see FIG. 1) and the opposite surface of the outer shell 12b made of a dielectric material is d2, and the capacitive coupling suppressing portion 12 is
When the width of e and 12f is W, their dimensions W and d1
, D2 are set so as to fall within the range that satisfies the above formula, and the respective dimensions of the second dielectric electrode 13 are also set in the same manner. Therefore, according to the present embodiment having such a configuration, the capacitance Coupling suppressing portions 12e, 12f, 13e, 13f
The discharge loss suppressing function as described above can be exerted as effectively as possible.

On the other hand, although there are many factors that make the discharge in the discharge space 14 unstable, it has been found that the partial temperature rise of the laser gas is greatly related to the discharge instability. This is thermal instability
This is due to the fact that the fluctuation of the electron density increases by an order of magnitude with the partial fluctuation of the laser gas density due to the temperature rise (the electron density changes by 10% as the laser gas density changes by 1%). ~ Fluctuate about 100 times). Therefore, when the laser gas flow in the discharge space 14 partially retains (stagnation), the discharge input at that portion locally raises the laser gas temperature, and the electron gas density fluctuates greatly due to the accompanying change in the laser gas density. However, the discharge in the discharge space 14 becomes unstable, and so-called filamentation occurs in some cases.

On the other hand, in the above embodiment, the lower surface of the first dielectric electrode 12 and the upper surface of the second dielectric electrode 13,
That is, the discharge space 1 in each outer shell 12b and 13b
Since the surface facing 4 is configured to have a planar shape along the flow of the laser gas in the discharge space 14, the laser gas can smoothly flow in the discharge space 14,
The possibility that the laser gas flow is partially retained is eliminated, and as a result, the stability of the discharge is increased, and the laser oscillation efficiency can be improved from this aspect as well.

The laser light 20 generated as described above is used.
Is brought into a resonance state by a reflecting mirror (not shown). However, when the resonance optical path of the laser light 20 is formed in a U shape or a Z shape, When it is necessary to set the width of 14 large, as shown in FIG. 7 showing the second embodiment of the present invention, the dielectric electrode 12 is formed.
The widths of the electrode portions 12a and 13a included in the electrodes 13 and 13 may be configured to be in a state corresponding to the resonance optical path of the laser light 20.

When it is necessary to set the width of the discharge space 14 large as described above, the electrode portion 12a (and 13a) is irradiated with the laser light 20 as shown in FIG. 8 showing the third embodiment of the present invention. The structure may be divided into two parts corresponding to each resonance optical path. In this case, the auxiliary partition wall 1 may be provided between the divided electrode parts.
2 g (only the first dielectric electrode 12 side is shown) may be additionally provided.

FIG. 9 and FIG. 10 show a fourth embodiment of the present invention, and only the parts different from the first embodiment will be described below.

In FIG. 9, the first dielectric electrode 21 and the second dielectric electrode 22, which are arranged opposite to each other with the discharge space 14 in between, have the same shape and are in a direction orthogonal to the laser gas flow (orthogonal to the paper surface). Rectangular shell-shaped outer shells 21a and 22a that are formed in a long shape in the same direction). These outer shells 21a and 22a are made of a dielectric material such as ceramics, and by partitioning the interiors of the outer shells 21a and 22a by partition walls 21b, 21c and 22b, 22c, three outer shells 21a and 22a extend in a direction orthogonal to the laser gas flow. The space portion is formed in an adjacent state. In this case, the central space portion is configured as the electrode storage chambers 21e and 22e for storing the electrode portions 21d and 22d having a circular cross-section, and the left and right space portions are formed from the outer shell portions 21a and 22a, respectively. The capacitive coupling suppressing portions 21f, 21g and 22f, 22g having a small rate are configured. In addition, these capacitive coupling suppressing units 21f,
21g, 22f, and 22g are configured to be extremely small in relative permittivity by communicating with the atmosphere or enclosing an insulating gas inside.

In the electrode storage chambers 21e and 22e,
For example, water C as a cooling medium is circulated, and hereinafter, a specific configuration of the electrode storage chamber 21e on the side of the first dielectric electrode 21 and a portion related thereto will be described with reference to FIG. To do. Since the structure of the second dielectric electrode 22 is basically the same as that of the first dielectric electrode 21, the description thereof will be omitted, and if it is necessary to refer to the second dielectric electrode 22, the same will be used. References will be made with reference numerals.

That is, in FIG. 10, openings 23 and 24 facing the electrode storage chamber 21e are formed in the upper surface portions of the outer shell 21a near both ends thereof.
The electrode storage chamber 21e is defined by fitting the resin sealing members 25 and 26 through the connector 4. In this case, the opening 23 located at one end (the right end in the drawing) of the outer shell 21a is formed with a relatively long dimension between itself and the end, and thus, The outer shell 21a
An air chamber 27 that is adjacent to the electrode storage chamber 21e via the seal member 25 is formed therein. In addition, this air chamber 2
7 is connected to the atmosphere.

Further, the seal member 25 is provided in the electrode storage chamber 21.
An outlet 25a communicating with the inside of e is formed, and the sealing member 2
6 is an inflow port 26 that also communicates with the electrode storage chamber 21e.
a is formed, and water C (see FIG. 9) circulates in the electrode storage chamber 21e through the inflow port 26a and the outflow port 25a.

The electrode portion 21d is supported through a plurality of silicon rubber spacers 28 which are intermittently arranged in the electrode storage chamber 21e, so that there is a gap between the electrode portion 21d and the inner wall of the electrode storage chamber 21e. It is provided so that
Thus, the water C is configured to flow around it.

A thin rod-shaped terminal 21h is integrally formed at one end of the electrode portion 21d so as to project therefrom.
Are watertightly penetrated through the seal member 25 and are projected into the air chamber 27. A resin terminal block 29 is attached to the end of the outer shell portion 21a, and the terminal 21h
Are connected to the relay terminals 29a on the terminal block 29 via lead wires 30. Incidentally, the relay terminal 29a
Is connected to a high frequency power supply.

According to this embodiment having such a configuration, the capacitive coupling suppressing portions 21f, 21g and 22f, 22g having extremely small relative dielectric constants are present on both sides of the electrode portions 21d and 22d. As in the first embodiment, the laser oscillation efficiency can be improved. In the present embodiment, the water C exists around the electrode portions 21d and 22d, but in general, water has a relatively high relative dielectric constant of about 80. It becomes convenient to be able to expect.

Further, according to this embodiment, the electrode storage chamber 21
e, the water C flowing in the 22e, the electrode portion 21d,
Since the temperature rise of 22d is suppressed, distortion of the dielectric electrodes 21 and 22 due to the difference in the coefficient of thermal expansion between the electrode portions 21d and 22d and the outer shell portions 21a and 22a. It becomes possible to prevent the occurrence. Therefore,
There is no possibility of causing cracks or the like at the lead-out portions (the seal member 25 in the case of this embodiment) of the electrode portions 21d and 22d to the outside of the electrode storage chambers 21e and 22e, and water caused by the cracks at the portions is eliminated. There will be no leakage or unnecessary discharge.

Further, in this embodiment, the outer shell portions 21a, 2
Since the air chamber 27 adjacent to the electrode accommodating chambers 21e and 22e via the seal member 25 is formed in 2a, and the terminal 21h of the electrode portions 21d and 22d is projected into the air chamber 27, the terminal 21h is formed. It becomes possible to reduce the electrostatic capacitance to the ground at a portion, and it is possible to prevent the occurrence of abnormal discharge at the terminal 21h, which is inevitably a sharp shape that tends to cause electric field concentration. Moreover, in this case, since the terminal 21h protruding into the air chamber 27 is connected to the power supply lead wire 30 in the air chamber 27, the ground capacitance of the lead wire 30 can be reduced. This makes it possible to prevent abnormal discharge in this portion.

Further, by controlling the electrostatic capacitance to the ground in this way, even if the electrostatic field on the surface of the dielectric reaches a value at which discharge can be generated, the electrostatic capacitance is reduced to maintain discharge. By preventing the supply of the electric charge necessary for the discharge, abnormal discharge can be prevented.

FIG. 11 shows a fifth embodiment of the present invention, and only the parts different from the first embodiment will be described below.

In FIG. 11, the first dielectric electrode 31 and the second dielectric electrode 32, which are opposed to each other with the discharge space 14 in between, have the same shape and are in a direction orthogonal to the laser gas flow (orthogonal to the paper surface). Rectangular shell-shaped outer shell portions 31a and 32a formed in a long shape in the same direction). These outer shell portions 31a and 32a are made of a dielectric material such as ceramics, and pipe-shaped electrode portions 31c and 32c extend in a direction orthogonal to the laser gas flow on the inner wall portions 31b and 32b facing each other. It is attached as follows. Note that such attachment is performed by brazing, for example.

The space portions formed around the electrode portions 31c and 32c in the outer shell portions 31a and 32a are connected to the atmosphere to serve as capacitive coupling suppressing portions 31d and 32d having extremely small relative permittivity. Function. Also,
Water as a cooling medium circulates in the electrode portions 31c and 32c.

Also in this embodiment having such a configuration, the capacitive coupling suppressing portions 31d and 32d having extremely small relative permittivity are present around the electrode portions 31c and 32c, so that the above-mentioned first As in the fourth embodiment, the laser oscillation efficiency can be improved, and the temperature rise of the electrode portions 31c and 32c can be suppressed by the water flowing inside. Therefore, as in the fourth embodiment. There is no risk of causing unnecessary distortion. Particularly in this embodiment, the electrode portion 31
Since c and 32c can also be used as a flow passage for water that is a cooling medium, the overall configuration can be simplified.

In the fifth embodiment, the electrode portion 31
When it is difficult to attach c and 32c, as shown in FIG. 12 showing the sixth embodiment of the present invention, the outer shell portions 31a and 32a are respectively attached to the container-shaped main body portions 31e and 32e.
The lid 31f and the lid 32f may be divided.

In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications may be made without departing from the scope of the invention, for example, a structure other than water may be used as the cooling medium. It can be implemented.

[0055]

As is apparent from the above description, according to the present invention, the electrode portion to which a high frequency voltage is applied is surrounded by
A gas laser oscillator in which at least a pair of dielectric electrodes each having an outer shell made of a dielectric material are arranged so as to sandwich a discharge space in which a laser gas circulates has the following effects.

According to the invention described in claim 1, since the capacitive coupling suppressing portion having a relative dielectric constant smaller than that of the outer shell portion is provided on both sides of the electrode portion of the dielectric electrode, a high frequency voltage is applied to the electrode portion. Even when applied, the discharge is suppressed from being dispersed to both sides of the electrode portion, and as a result, the laser oscillation efficiency can be improved even though the structure uses the dielectric electrode. .

According to the second aspect of the present invention, since the capacitive coupling suppressing portion is composed of the space portion formed by partitioning the inside of the outer shell portion with the partition wall, the space portion can be communicated with the atmosphere. Alternatively, by enclosing the insulating gas in the space, the relative permittivity in the capacitive coupling suppressing part can be made extremely small, which makes it possible to sufficiently reduce the capacitive coupling through the space. As a result, the effect of suppressing the dispersion of discharge can be further enhanced.

According to the third aspect of the invention, since the cooling medium is circulated in the electrode accommodating chamber formed by partitioning the outer shell portion by the partition wall, the electrodes accommodated in the electrode accommodating chamber are arranged. As a result, it is possible to prevent the inconvenience caused by the distortion between the electrode portion and the outer shell of the dielectric electrode due to the difference in the coefficient of thermal expansion between the two portions. Like

According to the invention of claim 4, an air chamber is formed in the outer shell portion so as to be adjacent to the electrode accommodating chamber via the seal member, and the end of the electrode portion existing in the electrode accommodating chamber is made to penetrate the seal member. Since it is configured to project into the air chamber,
The capacitance to ground at the end of the electrode can be lowered,
It becomes possible to prevent the occurrence of abnormal discharge at the end portion of the electrode portion, which is unavoidably shaped to easily cause electric field concentration.

According to the fifth aspect of the invention, since the end portion of the electrode portion projecting into the air chamber is connected to the power source lead wire in the air chamber as described above, the grounding of the lead wire to ground is performed. The electric capacity can be reduced, and abnormal discharge in this portion can be prevented.

According to the sixth aspect of the present invention, the pipe-shaped electrode portion is attached to the inner wall of the outer shell portion formed in a container shape, so that the space portion formed around the electrode portion is suppressed in capacitive coupling. Since the cooling medium is circulated in the electrode portion while functioning as a portion, the electrode portion can also be used as the cooling medium flow passage, and the overall configuration can be simplified.

According to the invention described in claim 7, the surface of the outer shell facing the discharge space is configured to have a planar shape along the flow of the laser gas in the discharge space.
The laser gas smoothly flows in the discharge space, and the instability of discharge is not increased due to the partial temperature rise of the laser gas.

According to the invention described in claim 8, the gap between the capacitive coupling suppressing portion and the surface of the dielectric outer shell facing the discharge space, the discharge space in the capacitive coupling suppressing portion and the dielectric outer shell, And the distance from the surface on the opposite side, and the width of the capacitive coupling suppression part,
Since the dimensions are set so as to effectively suppress the leakage discharge current in the capacitive coupling suppressing section, the discharge loss suppressing function of the capacitive coupling suppressing section can be maximized.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional front view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a state where a pair of dielectric electrodes are partially sectioned.

FIG. 3 is a vertical sectional front view for explaining the dimensional relationship of dielectric electrodes.

FIG. 4 is a diagram showing an example of a discharge current distribution in a dielectric electrode.

FIG. 5 is a characteristic curve diagram of the leakage current value calculated by calculation.

FIG. 6 is a diagram showing dimensional characteristics of a dielectric electrode that can withstand practical use.

FIG. 7 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

FIG. 8 shows a third embodiment of the present invention, and is a perspective view showing one of the dielectric electrodes in a partially sectioned state.

FIG. 9 is a view corresponding to FIG. 2 showing a fourth embodiment of the present invention.

FIG. 10 is a vertical sectional side view of a main part.

FIG. 11 is a view corresponding to FIG. 2 showing a fifth embodiment of the present invention.

FIG. 12 is a view corresponding to FIG. 2 showing a sixth embodiment of the present invention.

FIG. 13 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

In the figure, 11 is a wind tunnel container, 12, 21 and 31 are first dielectric electrodes, 13, 22 and 32 are second dielectric electrodes, 14 is a discharge space, 12a, 13a, 21d, 22d and 31c,
32c is an electrode part, 12b, 13b, 21a, 22a, 3
1a and 32a are outer shell parts, 12c, 12d, 13c and 13
d is a partition wall, 12e, 13e, 12f, 13f, 21
f, 22f, 21g, 22g, 31d and 32d are capacitive coupling suppressing parts, 19 is a high frequency power supply, 25 and 26 are sealing members, 27 is an air chamber, 28 is a spacer, 30 is a power supply lead wire, and C is water (cooling). Medium).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location 8934-4M H01S 3/04 G (72) Inventor Toru Tamagawa 2 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 stock company Toshiba Hamakawasaki factory

Claims (8)

[Claims] 1. At least a pair of dielectric electrodes, each of which has an outer shell made of a dielectric material provided around the electrode portion, are arranged with a discharge space in which a laser gas circulates therebetween, and a high-frequency voltage is applied between the electrode portions. The gas laser oscillator according to claim 1, wherein a capacitive coupling suppressing portion having a relative dielectric constant smaller than that of the outer shell portion is provided on both sides of the electrode portion of the dielectric electrode. 2. The gas laser oscillator according to claim 1, wherein the capacitive coupling suppressor is composed of a space formed by partitioning the inside of the outer shell with a partition wall. 3. An electrode housing chamber for housing the electrode portion is formed by partitioning the outer shell portion with a partition wall, and a cooling medium is circulated in the electrode housing chamber. Item 1. A gas laser oscillator according to item 1. 4. An air chamber is formed inside the outer shell so as to be adjacent to the electrode housing chamber via a seal member, and an end portion of the electrode portion existing in the electrode housing chamber is penetrated through the seal member to enter the air chamber. The gas laser oscillator according to claim 3, wherein the gas laser oscillator is configured to project. 5. The end portion of the electrode portion projected into the air chamber,
The gas laser oscillator according to claim 4, wherein the gas laser oscillator is configured to be connected to a power supply lead wire in the air chamber. 6. A pipe-shaped electrode portion is attached to an inner wall of an outer shell portion formed in a container shape so that a space portion formed around the electrode portion functions as a capacitive coupling suppressing portion, and The gas laser oscillator according to claim 1, wherein the cooling medium is circulated in the electrode portion. 7. The gas laser oscillator according to claim 1, wherein the surface of the outer shell facing the discharge space is configured to have a planar shape along the flow of the laser gas in the discharge space. 8. The distance between the capacitive coupling suppressing portion and the surface of the dielectric outer shell facing the discharge space is d1, and the surface of the capacitive coupling suppressing portion and the dielectric outer shell opposite to the discharge space. Is D2, the width of the capacitive coupling suppressing portion is W, the thickness of the dielectric outer shell portion at a portion corresponding to the electrode portion is D, and the relative permittivity of the dielectric outer shell portion is ε1. , D1 and d where the relative permittivity of the capacitive coupling suppressing portion is ε2.
2. The gas laser oscillator according to claim 1, wherein the following relationship is established between 2, W, D, ε1 and ε2. d1-11.ltoreq .- (. epsilon.2 / .epsilon.1) .times.10.times.D / 5.times. (25-2.times.d2) / W However, each unit of d1, d2, W and D is mm.