JPS61159781A - Silent discharge type gas laser device - Google Patents

Abstract

PURPOSE:To increase an output from a gas laser device by coating the surface of at least one electrode of a grounding-side metallic electrode and a high- voltage side metallic electrode with dielectric glass containing bismuth oxide. CONSTITUTION:Dielectric glass 12 coating the surface of a high-voltage side metallic electrode 2 opposing a grounding-side metallic electrode 1 contains bismuth oxide, and can be adjusted through the manufacture of a normal enamel frit. Consequently, discharge power density can be increased remarkably, and a laser can be oscillated at low voltage or low supply frequency on the same power density. When the content of bismuth oxide exceeds 80wt%, glass is crystallized remarkably, and is inappropriate for an application and a baking to a discharge tube; when the content is smaller than 10wt%, a specific inductive capacity is not so large, and discharge power density hardly increases.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a silent discharge type gas laser device.

[Conventional technology]

First, the conventional gas laser
．． The wt electrode (2) is the π high voltage side metal electrode disposed opposite to this ground side metal electrode (1), and the discharge surface is covered with a dielectric material (3) made of a material such as lead-containing glass or mica. There is. Both electrodes are filled with laser medium gas T;
Inside the container Iζ is provided, (4) is a discharge space, (5)
is a transformer, (6) is a high frequency power supply, (7) is a total reflection mirror, (
8) is a total reflection mirror (7) and an output side reflection mirror placed on the optical axis of the laser beam (partially transmitted), (9) is a cooling water circulation pump, αO is a cooler, and 0'0 is an ion This is a replacement water purifier.

In the above configuration, when an AC high voltage is applied to the high voltage side metal electrode (2) from the high frequency electric image (6) and the transformer (5), a stable discharge called silent discharge occurs in the discharge space (4). Since the silent discharge is an alternating current discharge through the dielectric (3) between the two electrodes, it does not transition to an arc discharge.
Although we will omit the explanation of the photoinduced radiation process caused by excited molecules C in the discharge space (4), in which a non-equilibrium discharge in which only the electron temperature is low and the molecular temperature does not rise can be stably realized, the discharge space (4) ), when a silent discharge occurs in the resonator formed by the total reflection mirror (7) and the output side reflection mirror (8), laser oscillation occurs in the resonator, and a laser beam is output from the output side reflection mirror (8). Both the ground side metal electrode (1) and the high voltage side G4 electrode (2) are cooled by cooling water with low electrical conductivity, and the cooling water is supplied to the cooling water circulating pump (9) and the cooler GO, The ion exchange water purifier αυ, which is circulated through the ion exchange water purifier 0υ, is necessary to reduce the electrical conductivity of the cooling water and prevent current leakage from the high voltage side metal electrode (2). Although not shown in the figure, gas in the discharge space is flowing at high speed between the electrodes in the direction of the I angle with respect to the laser beam.

Figure 5 is an enlarged view of the above-mentioned several K-AI section, and the discharge surface is parallel flat, together with the ground side metal electrode (1) and the high voltage side metal electrode (2), and the discharge is as shown in the figure (ζ). In the embodiment shown in FIG. 5, the dielectric is provided on the high voltage side metal electrode side, but it may be provided on the ground side metal electrode and on the high voltage side metal electrode and the ground side. It is clear that the same effect can be obtained by providing the metal electrodes on both sides. Fig. 6 shows an example in which dielectrics are provided on both the high voltage and ground sides (Milt&).

γ<= at which laser oscillation occurs means that laser gain is required in the discharge space to overcome the loss of the reflector (7) and output side reflector (8), and the laser gain is determined by the laser gain in the optical axis direction of the discharge space. Length and release! Since it is determined by the g power density (discharge power input per unit volume), if the length in the optical axis direction is determined, oscillation will not occur unless the discharge power density is raised above the value, increasing the discharge power density. [Problems to be solved by the invention] Conventional silent discharge gas laser equipment is constructed as described above, and the practical power supply frequency is about 100 fez at most, and there is a limit to increasing the applied voltage due to end insulation. Furthermore, the dielectric constant of the dielectric is at most 7.
Therefore, there was a limit to the improvement of the discharge power density.This invention eliminates the drawbacks of the conventional ones as described above.
[First means to solve the problem] The gas laser device according to the present invention has an NI4 electrode on the ground side,
At least one electrode surface of the high voltage side metal electrode is coated with dielectric glass containing bismuth oxide. [Function] In this invention number ζ, the ground side metal electrode and the high voltage side metal '
The dielectric glass containing high dielectric constant bismuth oxide coated on the surface of at least one of the NL electrodes is used to increase the power density and improve the output of the gas laser device.

[Embodiments of the invention]

Fig. 1 is a diagram showing the principle of construction of an embodiment of the present invention, Fig. 2 is an enlarged view of the discharge electrode section in Fig. 1, and Fig. 8 is a diagram showing the dielectric material provided on both the high voltage and ground side metal electrodes. It is an enlarged view of the discharge electrode part which is another Example.

In the figure, (1), (2), and (41 to α〃) are exactly the same as the above-mentioned conventional device. @ is a dielectric glass that covers the electrode surface. This dielectric glass Q2fζ will be explained in detail.
The dielectric glass υ can be adjusted by the usual method of manufacturing enamel fleet. An example of adjustment is shown below: Bismuth oxide 5Qwt%, 8i0 5wt%, AJ
203Q0gwt%, NazOjLtO and Liz04
Total 0.2wt%jsa012wt%, Ua01.5
wt%, total of CoO, NiO and ZnOIt, Q, 5w
t%, B20th Qwt%ke, melted at a temperature of 950℃ for about 45 minutes, put into water and quenched.The quenched glass is further crushed into lζ powder and applied to the metal tube by spray painting method etc. Table 1 shows the electrical properties of bismuth oxide-containing glass, which is a dielectric glass obtained by this method.7 Note that if the content of bismuth oxide is 80% by weight or more, the crystallization of the glass will be significant. It is unsuitable for coating and firing discharge tubes.

On the other hand, when the content of bismuth oxide is less than 1ON amount%, the dielectric constant is not so large and the increase in discharge power density is small.A bismuth oxide-containing dielectric glass with a dielectric constant of 18 is used in conventional 'r-electrodes. The relative permittivity of the dielectric material used is 15 times as much as the relative permittivity of 5. Therefore, the discharge power density can be significantly increased. As long as the power density is the same, laser oscillation is possible with a lower voltage or lower power frequency.

For example, in a silent discharge type 00z gas laser device, when the frequency is from several 10tLfiz to several 1001)1z, the discharge power W is the power supply frequency f, the electrostatic capacitance of the dielectric of the laser electrode j
It is known that there is a proportional relationship iog@ifζ. Therefore, by increasing the power supply frequency f or the electrostatic valley type Cg of the dielectric, the discharge power can be increased.

On the other hand, increasing the discharge voltage is also effective as a means of increasing the discharge power, but due to restrictions such as the withstand voltage of the insulating material used for the electrodes, the electrode structure becomes complicated, and the discharge voltage is usually 15~HLV at most. Also, the power supply frequency f is a number IQ
Although it is technically possible to design to Q Kflz,
1. High frequency, high loss in cables and connecting conductors during power transmission (due to high frequency skin effect), high loss inside electrical equipment such as high frequency transformers 2. As a result, the output of the high frequency power supply oscillator There is a drawback that the radio waves are reduced before reaching the discharge electrode part, resulting in a decrease in efficiency, and countermeasures against leakage radio waves are also required. [Effects of the Invention] As described above, according to the present invention, Since at least one electrode surface number of the gold electrode on the side voltage side is coated with dielectric glass containing bismuth oxide with a high dielectric constant, it is possible to reduce the *m frequency or lower the voltage and increase the electrostatic capacitance. It is possible to improve the output of the gas wreze device, which has a ricocheting effect6.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of construction of an embodiment of the present invention, Fig. 2 is an enlarged view of the discharge electrode section of Fig. 1, and Fig. 8 is a diagram showing the high voltage and ground side electrodes provided with dual dielectrics. Figure 4 is an enlarged view of the discharge electrode part of another embodiment, Figure 4 is a diagram of the configuration principle of a conventional silent discharge gas laser device, Figure 5 is an enlarged view of the discharge electrode part of Figure 4, and Figure 6 is a high-level view. Dielectric material is provided on both the voltage and ground side electrodes, = This is an enlarged view of the discharge section in the example. In the figure, (1) is the ground side metal electrode, (2) is the island voltage side metal electrode, (7) ) is a total reflection mirror, (8) is an output side reflection mirror, and (8) is a dielectric glass. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) A container filled with laser medium gas, metal electrodes placed opposite each other in this container, and mirrors placed on both sides of the optical axis of the laser beam that is excited and emitted by the discharge between these two electrodes. A silent discharge type gas laser device, characterized in that the surface of at least one of the re-electrodes is coated with dielectric glass containing bismuth oxide. (2) Dielectric glass has a bismuth oxide content of 10 to 8
The silent discharge type gas laser device according to claim 1, wherein the content is 0% by weight. (3) The dielectric glass contains 10 to 67% by weight of SiO_2 as glass components other than bismuth oxide.
, B_2O_3 is 30% by weight or less, Al_2O_3 is 1
0% by weight or less, one or more metal oxides selected from the group consisting of Na_2O, K_2O, Li_2O
Weight% or less, BaO, CaO, MgO, SrO and Sb
40% by weight or less of two or more metal oxides selected from the group consisting of _2O_3, CoO, MgO, ZnONiO,
3. The silent discharge gas laser device according to claim 2, wherein the content of one or more metal oxides selected from the group of Fe_2O_3 and TiO_2 is 5% by weight or less.