JPH0593063U - Laser oscillator - Google Patents

Abstract

(57) [Abstract] [Purpose] To suppress the expansion of the discharge space in a laser oscillator. [Structure] A glass tube 21 in which an insulating gas is sealed is provided near the metal electrode 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high frequency discharge excitation type laser oscillator.

[0002]

[Prior Art]

 FIG. 7 is a sectional view showing an example of a conventional laser oscillator. Inside the vacuum vessel 10 having a rectangular cross section, a heat exchanger 11 and a blower 12 are provided below the inside, and an electrode portion 14 is provided above the inside. FIG. 8 is a diagram showing details of the electrode portion 14. Since the electrode portion 14 has a vertically symmetrical structure, only the upper side will be described. The insulating material 2 is attached to the lower surface of the attachment plate 7 with bolts 6. Then, a metal electrode 3 and a dielectric 1 having a larger area than the metal electrode 3 are fixed to the lower portion of the insulating material 2 via an adhesive material 4. A water-cooling metal pipe 5 penetrates the mounting plate 7 and the insulating material 2 and is piped so as to contact the adhesive material 4 and the metal electrode 3.

The operation of such a configuration will be described below. The inside of the vacuum container 10 is filled with a laser medium gas (mixed gas of He, N ₂ , and CO ₂ ) at a pressure of 45 to 60 torr. When a high voltage supplied from a high frequency power source (not shown) is applied to the metal electrode 3, a stable discharge is generated in the discharge space 9. Laser light passing through the optical paths 13a and 13b can be obtained by the stimulated emission action of CO ₂ gas molecules excited by this discharge and the operation of the optical resonator using the total reflection mirror and the semi-transmission mirror. The laser medium gas heated by the discharge is circulated by the blower 12 in the gas circulation path 16 formed by the rectifying duct 15 in the direction of the arrow (Gas Flow) shown in the figure, and after being cooled by the heat exchanger 11. Used for discharging again.

[0004]

[Problems to be solved by the device]

 In the conventional laser oscillator described above, for example, a mica integrated material having a relative dielectric constant of 3 is used as an insulating material, a quartz plate glass having a relative dielectric constant of 3 is used as a dielectric, and a relative dielectric constant of 4. When the silicone of No. 3 is used and a high frequency voltage of 2 MHz is applied under the conditions of a distance between electrodes of 30 mm and a pressure of 50 torr, the discharge space length increases to about 100 mm for a metal electrode length of 50 mm. Therefore, there are the following problems. 1. It is necessary to maintain a sufficient insulation distance between the discharge space and the surrounding metal part having the GND potential. Therefore, the laser oscillator itself becomes large. 2. Since the metal electrode is water-cooled, the portion directly below the metal electrode of the dielectric is sufficiently cooled, but the end portion of the dielectric is not sufficiently cooled. Therefore, there is a considerable temperature rise at the end of the dielectric, and the characteristics of that part deteriorate. The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a laser oscillation device capable of suppressing the expansion of the discharge space.

[0005]

[Means for Solving the Problems]

 The present invention relates to a high-frequency discharge excitation type laser oscillating device that obtains laser light by generating an electric discharge between a pair of metal electrodes. The above object of the present invention is to enclose an insulating gas inside. This is achieved by arranging a glass tube in the vicinity of the metal electrode or disposing an electric field smoothing electrode having the same potential as the metal electrode in the vicinity of the metal electrode.

[0006]

[Action]

 According to the present invention, the electric current flowing inside the insulating material is suppressed or the electric field strength inside the insulating material is suppressed, so that the expansion of the discharge space can be suppressed.

[0007]

【Example】

FIG. 1 is a view showing a first example of an electrode portion of a laser oscillator according to the present invention in correspondence with FIG. Since the electrode portion has a vertically symmetrical structure, only the upper portion will be described. Inside the insulating material 2 on both sides of the metal electrode 3, a glass tube 21 in which gas is sealed is laid through an adhesive material 22. The gas filled in the glass tube 21 may be one having a high dielectric breakdown voltage and a specific dielectric constant close to 1, such as air, N ₂ , CO ₂ , F or Ar. Can be used. The gas pressure may be such that no discharge occurs, and is in the range of 0.5 atm to several atm.

FIG. 3 and FIG. 4 are diagrams showing, by computer simulation, the isopotential lines of the electric field in the discharge region of the first inventive and conventional laser oscillators. The region of the insulating material 2 surrounded by abfe and hgcd has a relative dielectric constant of 3, and the region of the discharge space surrounded by efgh has a relative dielectric constant of 1. Further, it is assumed that the glass tube 21 is filled with a gas having a relative permittivity of 1 and that no discharge occurs inside the glass tube 21. Then, the upper metal electrode 3 is set to + 2000V and the lower metal electrode 3 is set to -2000V, and the side abcd is set to the GND potential. Since there is almost no difference between the equipotential lines of the two, when the current flowing through BB ′ in FIG. 4 is 1, the current flowing through AA ′ in FIG. 3 has a relative dielectric constant of 1 inside the glass tube 21. Therefore, it becomes 0.3. Therefore, the discharge current generated in the F portion of FIG. 3 is 0.3 times the discharge current generated in the G portion of FIG.

FIG. 2 is a view showing a second example of the electrode portion of the laser oscillator of the present invention in correspondence with FIG. 8, and the same components are designated by the same reference numerals and the description thereof will be omitted. Since the electrode portion has a vertically symmetrical structure, only the upper portion will be described. A rod-shaped electric field smoothing electrode 23 is disposed via an adhesive material 24 inside the insulating material 2 on both sides of the metal electrode 3 and at an intermediate position between the high voltage potential portion and the GND potential portion. Since the electric field smoothing electrode 23 has the same potential as the metal electrode 3, it is electrically connected inside or outside the insulating material 2. The shape of the electric field smoothing electrode 23 is not particularly limited as long as it has no protrusion in the direction of the different potential portion in order to make the electric field uniform, and may be a round bar, a square bar or the like.

FIG. 5 and FIG. 6 are views showing the electric field in the discharge region of the second invention and the conventional laser oscillation device calculated by computer simulation. The region of the insulating material 2 surrounded by abfe and hg cd has a relative dielectric constant of 3, and the region of the discharge space surrounded by efgh has a relative dielectric constant of 1. Then, the upper metal electrode 3 is set to + 2000V, the lower metal electrode 3 is set to -2000V, and the side abcd is set to the GND potential. Since the discharge has a constant voltage load, it has no effect of suppressing the discharge current, and the electric field strength (voltage) generated inside the insulating material 2 suppresses the discharge current. Therefore, it is considered that the discharge space is determined by the electric field strength generated inside the insulating material 2. Since the electric field intensity on EE 'and the electric field intensity on DD' in FIG. 6 are the same as about 70 V / mm, similar discharges occur in J section and K section. On the other hand, since the electric field strength on CC 'in FIG. 5 is about 52.5 V / mm, the discharge current of the I part is reduced to about 75% of the discharge current of the H part.

[0011]

[Effect of the device]

 As described above, according to the laser oscillator of the present invention, the expansion of the discharge space can be suppressed, so that the discharge space can be designed small and the laser oscillator itself can be miniaturized. It is possible to suppress the temperature rise at the end of the body and prevent the deterioration of the characteristics of that part.

[Brief description of drawings]

FIG. 1 is a diagram showing a first example of an electrode portion of a laser oscillator of the present invention.

FIG. 2 is a diagram showing a second example of the electrode portion of the laser oscillator of the present invention.

FIG. 3 is a diagram showing an electric field in a discharge region in the first device of the present invention.

FIG. 4 is a diagram showing an electric field in a discharge region in a conventional device compared with FIG.

FIG. 5 is a diagram showing an electric field in a discharge region in the second device of the present invention.

FIG. 6 is a diagram showing an electric field in a discharge region in a conventional device compared with FIG.

FIG. 7 is a diagram showing an example of a conventional laser oscillation device.

FIG. 8 is a diagram showing an example of an electrode portion of a conventional laser oscillation device.

[Explanation of symbols]

 21 glass tube 22, 24 adhesive 23 electric field smoothing electrode

Claims (2)

[Scope of utility model registration request] 1. In a high-frequency discharge excitation type laser oscillating device for obtaining a laser beam by generating an electric discharge between a pair of metal electrodes, a glass tube in which an insulating gas is enclosed is provided near the metal electrodes. A laser oscillator characterized by the above. 2. In a high-frequency discharge excitation type laser oscillation device for obtaining a laser beam by generating a discharge between a pair of metal electrodes, an electric field smoothing electrode having the same potential as the metal electrodes is provided in the vicinity of the metal electrodes. A laser oscillator characterized by the above.