JP2011049444A - Gas laser oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser oscillator that is compact, lightweight and inexpensive, does not require an airtight structure, is easy to handle since a discharge electrode container is not easily broken, and has a discharge electrode preventing a water leak and dew condensation in the discharge electrode container. <P>SOLUTION: A discharge box 12 has an easy-to-break inorganic insulator only on a surface where the discharge electrode 2 is provided and other surfaces are made of inorganic metal which is not easily broken, so attention may be paid only to a surface of the discharge electrode 2 during assembly and handling thereof is easier. Further, the insulator 16 is charged in the discharge box 12 and no large pressure difference is generated between the inside and outside of the discharge box 12, so strength is secured even when thin inorganic metal is used for the container 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to the structure of a discharge electrode used in a discharge excitation gas laser oscillator.

  A discharge electrode of a conventional discharge excitation gas laser apparatus has a structure in which a metal electrode is covered with a discharge limiting material made of an organic insulator such as silicon rubber (see, for example, Patent Document 1). In addition, there is a discharge electrode in which a conductive electrode is installed in an air atmosphere separated from a laser medium gas in a casing by a container, and the container is configured to be vacuum tight with respect to the casing (for example, Patent Document 2). reference).

Japanese Patent Laid-Open No. 6-283382 JP2002-261356

  In the conventional discharge-excited gas laser oscillator described in Patent Document 1, a discharge limiting material made of an organic insulator such as silicon rubber is decomposed and deteriorated by an ultraviolet ray generated due to discharge or an active gas having high reactivity. Decomposed contaminants cause laser medium gas degradation and mirror contamination. In a conventional discharge electrode, the discharge limiting material made of organic insulator such as silicon rubber is covered with an inorganic insulating material, so that the discharge limiting material due to ultraviolet rays generated due to the discharge or highly reactive active gas. Degradation is suppressed. However, since inorganic insulators are easily damaged, such as cracks, they must be handled with care. In addition, when cracking occurs, ultraviolet light or active gas is irradiated and invaded through the gap, and the discharge limiting material is decomposed and deteriorated.

  Further, the discharge electrode disclosed in Patent Document 2 is configured such that the interior of the container is an air atmosphere separated from the laser medium gas atmosphere of the housing. For example, in the case of a carbon dioxide laser, the laser gas pressure in the casing is usually about 7 kPa to 33 kPa, and the container needs to be strong enough to withstand the pressure difference from the atmospheric pressure of 101.325 kPa. For this reason, the container becomes thick in order to ensure strength, leading to an increase in the size and weight of the discharge electrode, and an expensive one. In addition, since an airtight structure is required for joining the container and the dielectric, the structure is complicated, and there is a problem that air flows into the laser gas atmosphere in the housing due to manufacturing defects. In addition, when the cooling means is provided in the discharge electrode, in a high temperature and high humidity environment such as water leakage from the cooling means or summer, the cooling means comes into contact with the air atmosphere, so condensation occurs inside the discharge electrode, There was a risk of discharge occurring inside the discharge electrode, causing damage to the water distribution pipe inside the electrode, causing further water leakage, resulting in insufficient cooling, and breaking the insulation base.

  The present invention has been made in order to eliminate the disadvantages of the conventional ones as described above, and is provided with a discharge electrode that is small, light and inexpensive, does not require an airtight structure, and that the discharge electrode container is hard to break and easy to handle. A gas laser oscillator is obtained.

  In the gas laser oscillator according to the present invention, the discharge box is formed of an inorganic insulator that is easily damaged only on the surface provided with the discharge electrode, and the other surface is made of an inorganic metal that is not easily damaged, and the insulator is further formed of the discharge box. The inside is filled.

  In the present invention, the discharge box is provided with an inorganic insulator that is easily damaged only on the surface provided with the discharge electrode, and the other surface is made of an inorganic metal that is not easily damaged, thereby facilitating handling. Further, by filling the inside of the discharge box with an insulator, a small, light and inexpensive discharge electrode can be obtained without requiring an airtight structure.

It is a figure showing the structure of the gas laser oscillator which shows Embodiment 1 of this invention. It is sectional drawing of the gas laser oscillator which shows Embodiment 1 of this invention. It is sectional drawing of the discharge electrode of the gas laser oscillator which is Embodiment 1 of this invention. It is sectional drawing of the gas laser oscillator which shows Embodiment 1 of this invention. It is sectional drawing of the discharge electrode of the gas laser oscillator which is Embodiment 2 of this invention. It is sectional drawing of the discharge electrode of the gas laser oscillator which is another example of Embodiment 2 of this invention.

Embodiment 1 FIG.
FIG. 1 shows the configuration of a laser oscillator according to Embodiment 1 for carrying out the present invention. In FIG. 1, 1 is a housing | casing and 2 is a discharge electrode. 3 is a discharge gap, 4 is a laser medium gas containing CO, CO2, O2, N2, He gas, etc., and 5 is a blower. Reference numerals 6 and 7 denote a total reflection mirror and a partial reflection mirror, respectively, for oscillating and amplifying the laser beam. Reference numeral 8 denotes a power supply for supplying a high frequency high voltage between the pair of discharge electrodes 2.

  In FIG. 1, a housing 1 is filled with a laser medium gas 4, and is circulated so as to pass between a pair of discharge electrodes 2 similarly housed by a blower 5 housed in a housing 1. Yes. A discharge is generated by applying an alternating voltage between the pair of discharge electrodes 2 to excite the laser medium gas 4 to generate an inversion distribution. The laser medium gas 4 in which the inversion distribution is generated in this way generates light and is reflected and amplified by the total reflection mirror 6 and the partial reflection mirror 7. The light L1 amplified between the resonance mirrors including the total reflection mirror 6 and the partial reflection mirror 7 is extracted from the partial reflection mirror 7 to the outside of the laser oscillator as laser light L2. The laser medium gas 4 that has been excited between the discharge electrodes 2 and has reached a high temperature is cooled while passing through a heat exchanger (not shown) and is circulated again between the discharge electrodes.

  FIG. 2 is a cross-sectional view taken along the line AA of the laser oscillator in FIG. In FIG. 2, 9 is a conductor electrode such as iron or copper, 10 is a plate-shaped dielectric, and ceramics are mainly used. The conductor electrode 9 is joined to one surface of the dielectric 10 by brazing or the like to form the discharge electrode 2. Reference numeral 11 denotes a container made of an inorganic metal such as aluminum, iron, and stainless steel that hardly cracks due to external impact. It arrange | positions so that the surface to which the conductor electrode 9 of the discharge electrode 2 was connected to the opening surface of this container 11 may face. Thereby, it is comprised so that the surface to which the conductor electrode 9 of the discharge electrode 2 was connected with the container 11 may be covered, and the discharge box 12 is comprised. As shown in FIG. 2, the set of discharge boxes 12 configured in this manner is arranged so that the discharge electrodes 2 face each other, and the surface on the side where the discharge electrodes 2 face each other is constituted by the dielectric 10, and the others The surface is made of an inorganic metal.

  Further, an insulator 16 is filled in the inside of the discharge box 12, that is, the space surrounded by the container 11 and the discharge electrode 2. Since the insulator 16 needs to be filled in a space, it is preferable to use a resin that can be easily molded by a mold. Although there are two types of resins, thermosetting resins and thermoplastic resins, it is more desirable to use thermosetting resins. The thermosetting resin is a resin that is cured by heating or mixing two types, but is a liquid at room temperature before curing, and is easy to manufacture in an operation of pouring into a mold and curing. On the other hand, since a thermoplastic resin is softened by heating and cooled and cured, equipment such as an injection molding machine is required for pouring into a mold, and it is inferior to a thermosetting resin in terms of ease of manufacture. Examples of the thermosetting resin include silicone rubber that is cured by mixing two liquid resin materials in an appropriate amount. In this case, it is easy to fill the discharge box 12 with resin, but care must be taken not to generate gaps or bubbles. This is because if there are gaps or bubbles in the discharge box 12, rupture or the like may occur when the inside of the housing 1 is evacuated.

  FIG. 3 is a view showing a method of connecting the dielectric 10 and the container 11 in the discharge box 12. In FIG. 3, the peripheral portion of the dielectric 10 is held in a form that is sandwiched between the end of the container 11 and the pressing member 19. Further, the pressing member 19 is fastened to the end of the container 11 with a screw, for example. As a result, it is not necessary to apply pressure locally, such as by directly screwing the end of the dielectric 10 that is easily damaged, and damage to the dielectric 10 can be prevented.

  FIG. 4 is a cross-sectional view of the laser oscillator other than A-A in FIG. 1 and shows the state of power supply to the discharge electrode 2. In FIG. 4, reference numeral 13 denotes a power supply line, which is connected to the discharge electrode 2, passes through the inside of the container 11, and passes through the bellows 14 disposed between the container 11 and the casing 1, and is viewed from the opening 15 of the casing 1. 1 is wired to the power source 8 indicated by 1. The inside of the bellows 7 may be filled with an insulator 16 or may be an air atmosphere connected to the outside of the housing 1 without being filled with the insulator 16 as shown in FIG. However, when the inside of the bellows 7 is an air atmosphere, a large pressure difference is generated between the inside of the bellows 7 and the outside. Therefore, the bellows 7 needs to be strong enough to withstand the pressure difference. On the other hand, when the inside of the bellows 7 is filled with the insulator 16, the insulator 16 to be filled is required. However, since a large pressure difference does not occur between the inside and outside of the bellows 7, the bellows 7 has an air atmosphere inside. There is no need for strength.

  In the gas laser oscillator configured as described above, the discharge box 12 is formed of an inorganic insulator that is easily damaged only on the surface on which the discharge electrode 2 is provided, and the other surface is formed of an inorganic metal that is not easily damaged. Therefore, it is only necessary to pay attention to the surface of the discharge electrode 2 at the time of assembly, and handling becomes easy. In addition, since the insulator 16 is filled in the discharge box 12 so that a large pressure difference does not occur between the inside and the outside of the discharge box 12, the container 11 can be made strong even if a thin inorganic metal plate is used. It can be secured. This makes it possible to obtain a discharge electrode that is small, light, inexpensive, does not require an airtight structure, and that the discharge electrode container is hard to break and easy to handle.

  In addition, it can also be reduced in weight by using a foamed resin for the insulator 16. Moreover, since the inorganic metal used for the container 11 is exposed to a laser gas atmosphere, it is desirable that the metal does not rust or corrode, and for example, stainless steel or aluminum is a preferable material.

Embodiment 2. FIG.
5 and 6 are cross-sectional views of the discharge electrode showing Embodiment 2 of the present invention, in which the cooling performance of the discharge electrode is improved as compared with the gas laser oscillator according to Embodiment 1. FIG. Hereinafter, parts different from the first embodiment will be described.

  In FIG. 5, a cooling pipe 17 is made of a metal such as copper or a synthetic resin, and has a structure in which water, nitrogen gas, or the like, which is a cooling medium, can flow inside, for example, a hole as shown in FIG. 20 The cooling tube 17 is fixed by an insulator 16 that fills the discharge box 12 as in the first embodiment. Further, since the cooling tube 17 is covered with the insulator 16, the insulator 16 serves as a sealing material, and when water is used as a cooling medium, water leakage from the cooling tube 17 can be prevented. Condensation does not occur inside the discharge box 12, and damage to the discharge electrode due to water leakage or condensation inside the discharge box 12 can be prevented.

  In FIG. 5, the cooling tube 17 is fixed by the insulator 16. However, in order to make the cooling tube 17 more closely contact the conductive counter electrode 9, the cooling member 17 is cooled in the discharge box 12 using the fixing member 18 as shown in FIG. 6. The tube 17 may be fixed. Here, it is desirable that the fixing member 18 has excellent mechanical properties, that is, tensile strength, elongation, rigidity, etc., has a high heat resistance temperature, and high electrical insulation properties. For example, polyoxymethylene (polyacetal) or polybutylene terephthalate resin is preferable. It consists of Further, the shape of the fixing member 18 is trapezoidal in cross section in FIG. 6, but if the cooling pipe 17 can be fixed, the shape may be appropriately determined.

  The action of the fixing member 18 is to improve the adhesion between the cooling pipe 17 and the conductive counter electrode 9, thereby comparing with the case where the cooling pipe 17 is fixed with the insulator 16 shown in FIG. 5. Although installation work and cost increase occur, the cooling efficiency can be further improved. Since the insulator 16 is filled between the fixing member 18 and the container 11 as in the first embodiment, the discharge electrode is caused by water leakage or condensation inside the discharge box 12 as in the configuration of FIG. Can also prevent damage.

  Although only one cooling pipe is shown in FIGS. 5 and 6, similarly, when there are many cooling pipes, they may be fixed by the insulator 16 or the fixing member 18. Further, by using a resin having excellent heat transfer properties (such as silicone rubber for heat dissipation) for the insulator 16 and the fixing member 18, the cooling efficiency can be improved, and the cooling pipe can be downsized and the cooling medium used. The amount can be reduced.

DESCRIPTION OF SYMBOLS 1 Case 2 Discharge electrode 4 Laser medium gas 9 Conductor electrode 10 Dielectric 11 Container 12 Discharge box 16 Insulator 17 Cooling pipe 18 Fixing member

Claims (7)

In a gas laser oscillator in which a laser gas is caused to flow between a pair of discharge electrodes, a high voltage is applied between the discharge electrodes to generate a discharge between the discharge electrodes, and the laser gas is excited to perform laser oscillation.
The discharge electrode includes a conductor electrode to which the high voltage is applied and a plate-shaped dielectric material in which the conductor electrode is joined to one surface, and the surface of the dielectric on the side where the conductor electrode is not joined. A container made of an inorganic metal that covers the surface of the discharge electrode that is disposed so as to face the conductive electrode.
A gas laser oscillator in which a space surrounded by the discharge electrode and the container is filled with an insulator.   The gas laser oscillator according to claim 1, wherein the insulator is a resin.   The gas laser oscillator according to claim 2, wherein the resin is a thermosetting resin.   The gas laser oscillator according to claim 2, wherein the resin is a foamed resin.   5. The gas laser oscillator according to claim 1, wherein the container is made of stainless steel or aluminum.   The gas laser oscillator according to claim 1, further comprising a cooling pipe for cooling the conductor electrode, wherein the cooling pipe is positioned by the insulator.   A housing that encloses the laser gas and houses the discharge electrode and the container, and an electric wire that is provided between the housing and the container and connects the conductor electrode and the power source, and the insulator inside. The gas laser oscillator according to claim 1, further comprising a bellows filled with a gas.

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