JPS63313881A - Silent discharge type gas laser device - Google Patents

Abstract

PURPOSE:To eliminate the need of facilities for cooling electrodes by coating one of the oppositely disposed electrodes with the dielectric of titanium silicate glass. CONSTITUTION:A discharge surface in a high voltage side metallic electrode 2 oppositely arranged to a ground side metallic electrode 1 is composed of the dielectric 3a of titanium silicate glass. The temperature of the dielectric electrode is elevated normally to approximately 300-400 deg.C by discharge, but titanium silicate glass has breakdown voltage of 10kV/mm or higher, the temperature of thermal shock resistance of 1000 deg.C or more and even an extremely small linear expansion coefficient of 0.5X10<-7>, and has optimum conditions as the dielectric electrode employed at high voltage and a high temperature. Accordingly, spontaneous cooling is enabled.

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, a conventional gas laser device will be explained using a horizontally pumped type 0021/- laser as an example.

Fig. 2 is a diagram showing the principle of its construction. (1) is a ground side metal electrode, (2) is a high voltage side metal electrode arranged opposite to this ground side metal electrode (1), and the discharge surface is, for example, It is covered with a dielectric (3) made of a material such as barium borosilicate glass. Both electrodes are provided in a container filled with laser medium gas. (4) is a discharge space, (5) is a transformer, (6) is a high frequency power supply, (7) is a total reflection mirror, (8)
are the total reflection mirror (7) and the output side reflection mirror placed on the optical axis of the laser beam (partially transmitted), (9) is the cooling water circulation pump, (10 is the cooler, and (b) is the ion exchanger. It is a 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 current (6) and the transformer (5), a stable discharge called silent discharge occurs in the discharge space (4). happens. Since the silent discharge is an alternating current discharge via the dielectric (3) between both electrodes, a non-equilibrium discharge in which only the electron temperature is high and the molecular temperature does not increase can be stably realized without transitioning to arc discharge. Although the explanation of the photoinduced radiation process by excited molecules in the discharge space (4) will be omitted, the discharge space (4)
4) When silent discharge occurs inside the resonator, laser oscillation occurs within the resonator consisting of the total reflection mirror (7) and the output side reflection mirror (8), and laser light is output from the output side reflection mirror (8). be done. Both the ground side metal electrode (1) and the high voltage side metal electrode (2) are cooled by cooling water with low electrical conductivity, and the cooling water is supplied by a cooling water circulation pump (9), a cooler αQ, and ion exchange pure water It is circulated through the container (b) into each electrode (1), (2). This suppresses the temperature rise of each electrode (1) and (2) due to the discharge of laser oscillation, and in particular reduces the temperature difference between the discharge surface of the dielectric (3) and the high voltage side metal electrode (2). It is something that maintains the value. The ion exchange water purifier (2) 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 flows at high speed between the electrodes in a direction perpendicular to the laser beam.

Figure 8 is an enlarged view of the discharge electrode section, and shows the ground side metal electrode (
1) The discharge surface together with the high-voltage side metal electrode (2) is a parallel plate, and discharge occurs uniformly between both electrodes as shown in the figure. By the way, as a method of covering the metal electrode with a dielectric material, in addition to providing the dielectric material (3) on the high voltage side metal electrode (2) side, there is also a method of providing the dielectric material (3) on the ground side 1i4 electrode (1), or as shown in Fig. 4. It is known that the metal electrode is provided on both the high voltage side metal electrode (2) and the ground side metal electrode (1).

[Problem that the invention seeks to solve]

In the conventional device, the dielectric (3) covering the metal electrode is made of barium borosilicate glass, which has a very low thermal shock resistance (100'CjJ), and must be cooled. Circulation pump (9) as equipment for
However, there were problems such as requiring expensive equipment such as a cooler and an ion exchange deionizer (b), as well as complicating the electrode structure and increasing the size of the device.

This invention was made to solve the above-mentioned problems, and aims to provide a silent discharge type gas laser device that does not require cooling equipment by configuring the dielectric material with a material that has high thermal shock resistance. shall be.

[Means for solving problems]

The silent discharge type gas laser device according to the present invention has at least one of metal electrodes disposed facing each other in a container filled with a laser medium gas coated with a dielectric material of titanium silicate glass.

[Effect]

The titanium silicate glass dielectric of the present invention has good electrical properties and thermal shock resistance at high temperatures, thereby preventing damage due to thermal shock and the like.

[Embodiments of the invention]

An embodiment of this invention will be described below. In FIG. 1, the same reference numerals as in FIG. 2, which shows the configuration of a conventional device, indicate the same parts and the explanation will be omitted. (2) is a high voltage side metal electrode disposed opposite to the ground side metal electrode (1), and the discharge surface is made of a dielectric material (8a) of titanium silicate glass. On the opposite side of the dielectric (8a) from the discharge surface, a thin conductive paste mainly made of copper is applied and the baking process is applied to form the feed electrode (2).
a), and furthermore, a power supply terminal (2
) is pressure-welded with a stainless steel brush. Next, the operation will be explained. The discharge space (4) with the above configuration
Silent discharge and laser oscillation are performed in the same manner as in the prior art, so their explanation will be omitted.

Next, a titanium silicate glass dielectric (8
In addition to the above-mentioned materials, quartz glass, lithium aluminosilicate crystallized glass, and barium borosilicate glass used in conventional devices are known as materials for the dielectric (8 &). ) is desirable to have excellent electrical properties and thermal shock resistance, and as shown in the table, titanium silicate glass is found to be the best in these respects.

In other words, lithium aluminosilicate crystallized glass and barium borosilicate glass have poor electrical properties (breakdown voltage IKV/sw or less) and thermal shock resistance at low temperatures (400"C), while quartz glass has poor electrical properties. Although its properties are good, its thermal shock resistance is poor.In this respect, titanium silicate glass has a dielectric breakdown voltage of 10KV/swJJ or higher, a thermal shock resistance of 1000°C or higher, and a coefficient of linear expansion of 0.5X1.
0, which is extremely small and has the optimum conditions for a dielectric electrode used under high voltage and high temperature.

Normally, the temperature of the dielectric electrode due to discharge is 800 to 400
℃, but as mentioned above, the dielectric breakdown voltage of titanium silicate glass in this temperature range is IQF, V/
fi, and the coefficient of linear expansion is extremely small, so even if the discharge is stopped or the output is suddenly increased, problems such as cracking will not occur at all.

However, in a laser device using titanium silicate glass as the dielectric material of the electrode, natural cooling is possible because the laser device has characteristics that can sufficiently withstand thermal shock.

〔Effect of the invention〕

As described above, according to the present invention, at least one of the opposing electrodes is coated with a dielectric material of titanium silicate glass, which eliminates the need for equipment for cooling the electrodes, making it possible to reduce the cost and size. This has the effect of providing a silent discharge type gas laser device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a silent discharge type gas laser device according to the present invention, FIG. 2 is a block diagram of a conventional device, and FIGS. 8 and 4 are partially enlarged views of the conventional device. In the figure, (1) is the metal electrode on the ground side, (2) is the metal electrode on the high voltage side, and is the dielectric material. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A container filled with a laser medium gas, metal electrodes placed opposite each other in the container, and mirrors placed on both sides of the optical axis of the laser beam that is excited and emitted by a silent discharge between the two electrodes. A silent discharge gas laser device comprising: a silent discharge gas laser device comprising: a surface of at least one of the electrodes is coated with a dielectric material of titanium silicate glass;