JPS59217382A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To enable the effective utilization of the power source capacity with a simple structure by providing one of electrodes on the outer wall of a cylindrical dielectric, and constructing the other in the form of passing the electrode wire along the inner wall. CONSTITUTION:The electrode 11-2 for power supply placed on the water-cooled side is provided on the inner wall of the dielectric 2, and the electrode 11-1 provided on the outer wall is on the side of ground for the power source. Thereby, since electrical insulation is kept in structure, a partition plate is unnecessitated, resulting in the simple structure of a laser oscillator by voiceless discharge, which can be manufactured at a low cost. Further, the most part of the current supplied from the power source flows to a discharge space 4, the current becoming a loss through the partition plate or cooling water can be neglected, and the power source capacity reduces.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the structure of a discharge tube of a gas laser oscillator, particularly a coaxial type gas laser oscillator.

A CO2 laser will be described as an example of a coaxial gas laser oscillator. This type of laser oscillates laser light by exciting the gas by discharging it in the gas, but there are two types of discharge: direct current glow discharge and alternating current silent discharge. is shown in Figure 1. Figure 1(a) is a configuration diagram of a conventional DC glow discharge type gas laser excavator, in which (1) is a cathode, (2) is a discharge tube made of a dielectric material such as glass, (3) is an anode, ( 4
) is the discharge space, (5) is the cooling jacket l-, +61
is a cooling water passage, (7) is a cooling water inlet, (8) is a cooling water outlet, and (9) is a total reflection mirror.

FIG is a partially reflecting mirror. Cathode (1) and anode (3
), a discharge called glow discharge is formed in the discharge space (4). In the case of a CO2 laser, a gas mixture of CO2-N2-He is normally sealed in the discharge space (4) at a pressure of several tens of Torr.

When a glow discharge occurs here, as a result, the CO2 molecules are excited to the upper level, and when they return from that state to the lower level, light with a wavelength of 10.6 μm is emitted.

This was photographed using the total reflection mirror 19) and the partial transmission mirror 1101.

The light is amplified and extracted as laser light, and the light is used for processing and cutting materials. Here, if we let the discharge occur (
The temperature of the discharge space (4) rises, but on the other hand, from the point of view of the excitation efficiency of the laser, the temperature of this space needs to be kept below approximately 200°C, so the laser gas is flowed into the discharge space (4) at high speed. (several tens of rn/sec), the heat generated by the discharge is carried away in the sink, and the discharge space (4) is cooled by the cooling water (6). By the output of the laser light, i.e. by the input of the discharge.

There are those that flow a gas flow into the discharge space (high output) and those that do not (low output), but at least the latter is small.

The so-called discharge tube shown in (2) is water-cooled.

1 The above has described a glow discharge type gas laser oscillator, but this type has a power of several Torr.
However, stable discharge can only be maintained under a laser gas pressure of several tens of Torr at most. On the other hand, from the viewpoint of gas deterioration (change in composition) due to laser gas discharge, a relatively high pressure (around 100 Torr or more) is better, and a glow discharge type is not necessarily optimal from the viewpoint of sealing off the laser gas. Not really.

This method requires maintenance to periodically replace the laser gas in order to stabilize the laser output. Therefore, recently, the above-mentioned silent discharge type laser has been considered and used.

FIG. 1(b) is a configuration diagram of a conventional silent discharge type gas laser excavator, and FIG. 1(c) is a sectional view taken along line A-A' in FIG. 1(b). In the figure, (11-1), (
11-2) is a pair of electrodes in close contact with the cylindrical dielectric body +21 (made of 'ff lath, barium titanate, etc.) containing the discharge space (4), and these pair of electrodes (n
-1), (11-2) When a high frequency AC high voltage of approximately KV is applied, a gentle discharge called a silent discharge is generated in the discharge space (4) through the dielectric (2), and the above-mentioned It oscillates laser light using the same principle as a DC glow discharge type gas laser oscillator. Silent discharge maintains a very stable discharge even under atmospheric pressure, and the discharge conditions of around 100 Torr used for laser oscillation are extremely stable, and gas deterioration, that is, a single composition change, hardly occurs. There are some features that don't exist. However, as shown in FIG. 1(C), a device that utilizes such silent discharge requires zero force from the diaphragm plate. Because the electrode (11-1),
When an AC high torque is applied between (11-2), the dielectric (2
) is water-cooled, so even if the water is deionized with an ion exchange resin, the relative dielectric constant of water is 80, so it is not supplied from the electrodes (11-1) and (11-2). Since most of the current flows through the water, a barrier plate Q2) h'- is installed. However, this diaphragm plate 0 is also made of dielectric material, and when an induced current flows through the diaphragm plate (12), some of the supplied current does not flow through the discharge space (4), and only that much current flows. It was Yokuma's loss. Further, producing such a partition plate OQ has the disadvantage that it leads to an increase in the cost of the apparatus.

This invention was made in order to eliminate the above-mentioned drawbacks of a silent discharge type gas laser excavator.
A simple structure with electrode wires running along the inner wall of a cylindrical dielectric.

The purpose is to provide a device that can effectively use the capacity of the power supply.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2(a) is a block diagram of a gas L.
It is a sectional view taken along the B' line. In the figure, (11-
1) is one of a pair of electrodes, and is a cylindrical electrode whose inner side is in close contact with the outer wall of a cylindrical dielectric (2).

(11-2) is the other electrode, which is an electrode wire made of, for example, metal and runs along the inner wall of the cylindrical dielectric (2).

In a gas laser oscillator with such a configuration, the electrode (11-
When an AC voltage is applied between 1) and (11-2).

Since the discharge occurs through the dielectric (2), the discharge space (4)
Then, a gentle discharge called a silent discharge is formed, which is the same as that shown in FIG. 1(b).

The principle of oscillating laser light by this silent discharge is the same as the conventional one, and in this invention, one of the electrodes is connected to the electrode wire (
11-2), the laser energy emitted in the discharge space 141 is effectively extracted without power loss. It has been experimentally confirmed that when the diameter of 11-2) is about one seagull, the laser oscillation efficiency does not decrease at all.

The difference between the structure of the discharge tube according to the present invention and the conventional one as described above is that first, the structure of the discharge tube according to the present invention has electrodes installed on the inner and outer walls of the dielectric (2). Since electrical insulation is structurally maintained, the partition plate 02 as in the conventional example is unnecessary.

Therefore, the structure of the laser oscillator is simplified and can be manufactured at low cost.

It is also shown in FIG. 1(b). The power supply electrode (11-2) installed on the water cooling side is shown in FIG. 2(a).

This is because the electrode (11-1) provided on the inner wall of the dielectric (2) and the electrode (11-1) provided on the outer wall of the dielectric can be used as the ground side of the power source.

1 There is no problem with the quality of the cooling water, there is no need to use deionized water passed through an ion exchange resin as in the past, and the cost of the gas laser excavator is lower and there is no need for maintenance to ensure water quality, making it more reliable. Improves sex. Furthermore, the current supplied from the power supply flows through most of the discharge space (4), and the current loss through the diaphragm plate 02) and cooling water, as in the conventional example, can be ignored, and the power supply capacity is also greater than in the conventional example. It has the advantage of being small.

By the way, in the case of silent discharge, if the power supply frequency and applied voltage are the same, the power input into the discharge space (4) is equal to the electrode (1).
1-1), dielectric (2) in close contact with (11-2)
is proportional to the area of However, in the conventional example, the electrode can only be brought into close contact with only a part of the surface of the dielectric (2) from above the structure, and in the case of the present invention, the electrode can be attached over the entire surface (entire circumference) of the dielectric. Since they can be in close contact with each other, the dielectric (2) is effectively utilized, and as a result, it becomes easier to input power into the discharge space (4). Namely.

When applying the same discharge power as the conventional device, the present invention requires a lower applied voltage, and has the advantage that the device is more reliable in terms of electrical insulation.

In addition, it is better for the discharge region formed in the discharge space (4) to be uniform from the point of view of laser excavation, and from this point of view as well, the dielectric (
It is also easy to understand that the invention in which the entire circumference of 2) is used as an electrode is superior.

Figure 3 shows the structure of the discharge tube that further improves the uniformity of the discharge area. FIG. 3(a) is a configuration diagram of a gas laser excavator according to another embodiment of the present invention, and FIG. 3(b) is a configuration diagram of a gas laser excavator according to another embodiment of the present invention.
It is a sectional view taken along the C-σ line in Figure (a). In Figure 3, the electrode wire (11-2) is spirally connected to one cylindrical dielectric body (2).
The electrode wire (
Since the current flowing from 11-2) to the discharge space (4) becomes uniform over the entire circumference of the inner wall of the dielectric, the formed discharge becomes more uniform, improving the efficiency of laser excavation. For this reason, the effect is produced by rotating the electrode wire (11-2) once in the circumferential direction of the discharge tube, but the same effect can be obtained even if the electrode wire (11-2) is rotated at a higher rotation speed than this, and the number of turns is arbitrary.

Although the above explanation is for the case where the electrode wire (11-2) is made of metal, the same effect can be obtained even if the electrode wire (11-2) is coated with an inorganic material such as glass or ceramic.

In addition, in the above embodiment, the CO2 laser oscillator is used, but any device that uses discharge as laser excitation may be used. Laser light oscillation may be continuous oscillation, or pulsed oscillation such as TEA (lateral direction Excitation atmospheric pressure: Tr
anversely Excited Atmosp
A similar effect can be obtained by using a laser having the structure of the present invention.

As described above, according to the present invention, one of the electrodes is provided on the outer wall of the cylindrical dielectric, and the other electrode is configured by having the electrode wire run along the inner wall of the cylindrical dielectric, resulting in a simple structure. This has the effect of almost eliminating current loss.

[Brief explanation of the drawing]

Figure 1 (a) is a diagram of a conventional DC glow discharge type gas laser excavator (Fig. 1 (0)) is a diagram of a conventional silent discharge type gas laser excavator; Figure 1 (c) is a diagram of a conventional silent discharge type gas laser excavator. is A in Figure 1(b)
- A' line sectional view, FIG.
b) is a sectional view taken along the line B-B' in FIG. 2(a), FIG. 3(a) is a block diagram of a gas laser oscillator according to another embodiment of the present invention, and FIG. 3(b) is a sectional view taken along line B-B' in FIG. (a) c - c
FIG. In the figure, (2) is a cylindrical dielectric, (4) is a discharge space, and (11-1) is one electrode. (11-2) is the other electrode made of an electrode wire. In addition, in FIG. 9, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa No. 11
Title of the invention: Gas laser oscillator 3, Representative Hitoshi Katayama of the person making the amendment Section 4, Agent & Detailed description of the invention in the specification to be amended. 6. "Water quality guarantee" in the first line of page 8 of the detailed statement of amendments is corrected to "water quality guarantee."that's all

Claims (4)

[Claims] (1) In a device that applies an alternating current voltage to a pair of electrodes that are in close contact with a cylindrical dielectric body containing a discharge space to cause a discharge and oscillate laser light, one of the electrodes is attached to a cylindrical dielectric body that includes a discharge space. A gas laser oscillator characterized in that the other electrode is provided on an outer wall, and the other electrode is configured with an electrode wire running along the inner wall of the cylindrical dielectric. (2) The gas laser oscillator according to claim 1, wherein one of the electrodes is constituted by a cylindrical electrode whose inner side is in close contact with the outer wall of a cylindrical dielectric. (3) The gas laser oscillator according to claim 1 or 2, wherein the electrode wire is spirally arranged along the inner wall of the cylindrical dielectric. (4) The gas laser oscillator according to any one of claims 1 to 3, wherein the electrode wire is coated with a dielectric material.