JPH07162060A - Gas laser - Google Patents

Abstract

PURPOSE:To enable preliminary ionization of a discharge space with high efficiency by using little energy. CONSTITUTION:A gas laser which generates laser light by discharging and pumping gas laser medium consists of the following; a laser tube 1 in which gas laser medium is contained, a main electrode 30 constituted of a first cathode 31 and a second anode 32 which are arranged in the laser tube so as to face each other, and a second cathode 41 and a second anode 42 whose length dimensions are smaller than the first cathode 31 and the second anode 31. In the laser tube 1, the following are arranged; an auxiliary electrode 40 arranged in series with the main electrode 30, a high voltage power supply 18 which applies a high voltage to the main electrode 30 and the auxiliary electrode 40 and ignites main discharge between the cathode and the anode of each electrode, and an X-ray tube 14 which preliminarily ionizes a discharge space part between the second cathode 41 and the second anode 42 of the auxiliary electrode 40, prior to the main discharge generated by the high voltage power supply 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device which excites a gas laser medium by electric discharge to generate laser light.

[0002]

_2. Description of the Related Art Generally, in a gas laser device such as a TEACO ₂ laser or an excimer laser, a cathode and an anode forming a main electrode are separated and face _each other in a laser tube containing a gas laser medium. By igniting the main discharge in the main discharge space between these electrodes, the gas laser medium is discharge-excited to generate laser light.

The discharge space is pre-ionized prior to the main discharge so that the main discharge is easily ignited. There are various methods for preionization, and when high output and long life are required, the X-ray preionization method using an X-ray tube is often adopted.

FIGS. 4 and 5 show a gas laser device using a conventional X-ray preionization system. In the figure, 1 is a laser tube.
The laser tube 1 has an opening at the top, and the opening has a flange 2
The gas laser medium is enclosed in the inside by an airtight structure. The gas laser medium is circulated by the blower 3 arranged in the laser tube 1 and maintained at a constant temperature by the heat exchanger 4.

A cathode 5 and an anode 6 are arranged in the laser tube 1 so as to face each other in the vertical direction with a space therebetween. The anode 6 is electrically connected to the inner surface of the flange 2 and the cathode 5 is electrically connected to the upper surface of the mounting plate 7. The cathode 5 and the anode 6 are connected to a first high-voltage power source 8, and when a high voltage is applied from the high-voltage power source 8, the discharge space 9 between the cathode 5 and the anode 6 is mainly charged. The discharge is ignited. A high reflection mirror 9a and an output mirror 9b forming an optical resonator are provided on both end faces of the laser tube 1 facing one end side and the other end side of the discharge space 9. .

Peaking capacitors 10 are arranged at predetermined intervals on both sides of the cathode 5. Each peaking capacitor 10 is for shaping the waveform of the main discharge,
The flange 2 and the mounting plate 7 are electrically connected via an electrode rod 11.

The anode 6 has a concave portion 1 which is open on the back side thereof.
3 are formed over substantially the entire length in the longitudinal direction, and a plurality of X-ray tubes 14 are arranged at predetermined intervals along the longitudinal direction above the anode 6 facing the recess 13.
As shown in FIG. 4, the X-ray tube 14 is provided with a window 15 on the front end surface thereof, a peripheral wall of the front end portion is formed into an anode 16, and a cathode 17 is provided inside.

In each X-ray tube 14, a high voltage is applied between the anode 16 and the cathode 17 by the second high-voltage power source 18, and the cathode 17 is heated by the heater transformer 19. Electric current is supplied. When the cathode 17 is heated by the heater transformer 19, thermoelectrons are generated, and when the second high-voltage power supply 18 operates, the thermoelectrons from the cathode 17 collide with the anode 16. As a result, X-rays are generated from the anode 16.

The X-ray generated in this way is the window 1
5 and the recess 13 of the anode 6 to reach the discharge space 9, and the discharge space 9 is pre-ionized before the main discharge is ignited between the cathode 5 and the anode 6.

The first high-voltage power supply 8 operates after a predetermined time delay from the operation of the second high-voltage power supply 18. Thereby,
The peaking capacitor 10 is charged and the cathode 5 and the anode 6 are charged.
, The main discharge is ignited in the preionized discharge space 9 and the gas laser medium is excited.

The laser light L generated by the discharge excitation of the gas laser medium is repeatedly reflected and amplified between the high reflection mirror 9a and the output mirror 9b forming the optical resonator, and the output mirror is output. Oscillation is output from 9b.

Since such an X-ray preionization system has a strong preionization capacity, when compared under the same conditions, the corona preionization system shown by the curve B as shown by the curve A in FIG. U to generate ultraviolet rays by the spark discharge shown
Higher laser output can be obtained as compared with the V preionization system.

However, when comparing the oscillation efficiencies, X
Since very high electric energy must be supplied to the ray tube 14, the X-ray preionization method shown by the curve A in FIG. 6B may be less efficient than other preionization methods.

Although it is conceivable to reduce the number of X-ray tubes 14 in order to increase the oscillation efficiency, the X-ray tube 1
If the number of 4 is reduced, the preionization in the region where the X-ray tube 14 does not exist becomes weak and the state of preionization in the discharge space 9 becomes non-uniform, resulting in a decrease in the laser output.

[0015]

As described above, in the conventional gas laser apparatus, when the X-ray tube is used as the preionization means for increasing the output, the supply energy and the output for the preionization are obtained. Ratio, that is, the oscillation efficiency is lower than that of other preionization means, and if the number of X-ray tubes is reduced in order to reduce the supplied energy, the preionization becomes non-uniform. This means that the output will decrease.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a discharge space portion so as not to cause a decrease in oscillation efficiency even if a supply energy for preionization is decreased. Another object of the present invention is to provide a gas laser device capable of performing preionization.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is a gas laser device for generating laser light by exciting a gas laser medium by discharge, wherein the gas laser medium is internally provided. A laser tube accommodated therein, a main electrode composed of a first cathode and a first anode arranged to face each other in the laser tube, and a length longer than the first cathode and the second anode. An auxiliary electrode composed of a second cathode and a second anode each having a short length and arranged in series with the main electrode in the laser tube; and applying a high voltage to the main electrode and the auxiliary electrode. A high-voltage power supply for igniting a main discharge between the cathode and the anode of each electrode, and a discharge space portion between the second cathode and the second anode of the auxiliary electrode prior to the main discharge by the high-voltage power supply. It is characterized by comprising a preionization means for preionization.

[0018]

According to the above construction, since the discharge space on the auxiliary electrode side is smaller than the discharge space on the main electrode side, the discharge space can be uniformly preionized by a small amount of supplied energy. When laser light is generated from the discharge space portion on the auxiliary electrode side, the laser light preionizes the discharge space portion on the main electrode side. Since the pre-ionization by the laser light is strong, the laser light with high output can be obtained with low energy consumption, so that the oscillation efficiency is improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Incidentally, the same parts as those of the conventional structure shown in FIGS. That is, in the gas laser device of the present invention, the first cathode 31 and the first anode 32 forming the main electrode 30 are arranged in the laser tube 1 so as to face each other in the vertical direction, and A second cathode 41 forming an auxiliary electrode 40 in series with this main electrode
And the second anode 42 are arranged.

The first cathode 31 and the second cathode 41 are mounted on the upper surface of the mounting plate 7 in an electrically conductive state, and the second anode 32 and the second anode 42 are mounted on the lower surface of the flange 2. These electrodes 3 are attached in an electrically conductive state.
0 and 40 are electrically connected to the first high-voltage power supply 8. A peaking capacitor 10 electrically connected to the mounting plate 7 and the flange 2 via a current-carrying rod 11 is provided on the side of each of the electrodes 30 and 40, and the anode 42 of the auxiliary electrode 40 is provided with the peaking capacitor 10. An open recess 44 is formed on the back side,
One X-ray tube 14 is arranged at a portion facing the recess 44. A second high voltage power source 18 and a heater transformer 19 are connected to the X-ray tube 14 as in the conventional structure.

The lengths of the cathode 31 and the anode 32 of the main electrode 30 are set sufficiently shorter than those of the cathode 41 and the anode 42 of the auxiliary electrode 40. For example, the main electrode 30 is set to have a length of about 60 to 100 mm, and the auxiliary electrode 4
0 is set to a length of about 6 to 10 mm, which corresponds to almost the diameter of the X-ray tube 14.

In the gas laser device having such a structure, first, the second high voltage power source 18 and the heater transformer 1 are provided.
9 operates and the X-ray pre-ionizes the discharge space 40a of the auxiliary electrode 40. The first high-voltage power supply 8 operates after a predetermined time delay from the operation of the second high-voltage power supply 18. Thereby, the cathode 41 and the anode 4 of the main electrode 30 and the auxiliary electrode 40 are formed.
A voltage is generated between the two.

Since the discharge space portion 40a of the auxiliary electrode 40 is preionized by the X-ray, the discharge space portion 40a is pre-ionized.
A discharge is ignited prior to the discharge space 30a of the main electrode 30, the gas laser medium is excited in the discharge space 40a, and laser light is generated. The laser light is repeatedly reflected by the total reflection mirror 9a and the output mirror 9b of the optical resonator.

The discharge space portion 30a of the main electrode 30 is preionized by the ultraviolet rays included in the discharge generated in the discharge space portion 40a of the auxiliary electrode 40 and the laser light generated by the auxiliary electrode 40. Thereby, the main electrode 4
The main discharge is also ignited in the zero discharge space 40a to generate laser light L. The laser light L is amplified by being repeatedly reflected by the total reflection mirror 9a and the output mirror 9b, and also amplified by passing through the discharge space portion 40a of the auxiliary electrode 40. High-power laser light L is oscillated and output from the mirror 9b.

Experiments have shown that the present invention provides X for preionization.
The output of the laser light L was almost the same as the value shown by the curve A in FIG. 6A, although the number of the line tubes 14 was one. Further, since the number of the X-ray tubes 14 is one, the power consumption required for the pre-ionization is significantly reduced as compared with the conventional one, and thus the oscillation efficiency is significantly higher than the value indicated by the curve C in FIG.

As described above, the electrode is divided into the main electrode 30 and the auxiliary electrode 40 having a length dimension shorter than that of the main electrode,
By pre-ionizing only the discharge space 40a on the auxiliary electrode 40 side, it is possible to obtain the laser light L of high output with high oscillation efficiency.

In the above embodiment, only one set of main electrodes is arranged, but a plurality of sets of main electrodes may be arranged in series. With such a configuration, the laser light L is amplified in the discharge space of each main electrode, so that the output can be further increased.

The means for pre-ionizing the discharge space 40a of the auxiliary electrode 40 may be the means shown in FIG. 3 (a) or 3 (b). That is, in FIG. 3A, an upper pin electrode 51 and a lower pin electrode 52, whose tips are opposed to each other with a predetermined gap, are arranged beside the cathode 41 and the anode 42 of the auxiliary electrode 40.

A spark discharge is ignited between the pin electrodes 51 and 52 to generate ultraviolet rays, and the ultraviolet rays pre-ionize the discharge space 40a.

In FIG. 3B, a groove 43 is formed on the upper surface of either the cathode 41 or the anode 42 of the auxiliary electrode 40,
A wire-shaped corona electrode 44 was arranged in the groove 43. The corona electrode 44 is inserted into a tube body 45 made of a dielectric material such as quartz.

Therefore, if a voltage is applied to the corona electrode 44 to ignite the corona discharge, the discharge space 40a of the auxiliary electrode 40 can be preionized by the ultraviolet rays generated thereby.

[0032]

As described above, according to the present invention, the main electrode composed of the first cathode and the first anode is provided in the laser tube, and the second cathode having a shorter length than the main electrode. The second anode and the empty auxiliary electrode were arranged in series, and the discharge space between the second cathode and the second anode of the auxiliary electrode was preionized.

Therefore, the discharge space of the auxiliary electrode, which is narrower than the discharge space of the main electrode, may be preionized.
The discharge space can be uniformly and strongly preionized with a small amount of energy, whereby laser light is generated from the discharge space of the auxiliary electrode, and the laser light causes the discharge space of the main electrode to be discharged. Since strong preionization is possible, high-power laser light can be obtained with high oscillation efficiency from the discharge space of the main electrode.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3A and FIG. 3B are configuration diagrams showing modified examples of the preionization means of the present invention.

FIG. 4 is a sectional view of a conventional gas laser device.

5 is a sectional view taken along line BB of FIG.

FIG. 6A is a bluff showing the relationship between the voltage applied to the preionization means and the laser output, and FIG. 6B is a bluff showing the relationship between the voltage applied to the preionization means and the oscillation efficiency.

[Explanation of symbols]

1 ... Laser tube, 8 ... 1st high voltage power supply, 14 ... X-ray tube, 3
0 ... Main electrode, 31 ... First cathode, 32 ... First anode, 4
0 ... auxiliary electrode, 41 ... second cathode, 42 ... second anode.

Claims (4)

[Claims] 1. A gas laser device for generating laser light by exciting a gas laser medium by discharge, and a laser tube having the gas laser medium housed therein, and a laser tube in the laser tube. From a main electrode composed of a first cathode and a first anode arranged opposite to each other, a second cathode and a second anode having a length dimension shorter than that of the first cathode and the second anode. Then, a high voltage is applied to the auxiliary electrode arranged in series with the main electrode in the laser tube and the main electrode and the auxiliary electrode to ignite the main discharge between the cathode and the anode of each electrode. And a preionization means for preionizing the discharge space between the second cathode and the second anode of the auxiliary electrode prior to the main discharge by the high voltage power supply. Gas laser device. 2. The gas laser apparatus according to claim 1, wherein the preionization means is an X-ray tube arranged behind one electrode of the auxiliary electrode for generating X-rays. 3. The pre-ionization means includes an upper pin electrode and a lower pin electrode which are arranged laterally to the second main electrode with their tips opposed to each other and spark discharge is ignited between the tips. The gas laser device according to claim 1, wherein the gas laser device is a pair of pin electrodes. 4. The gas ionizer according to claim 1, wherein the preionization means is a corona electrode which is disposed in proximity to one of the second main electrodes and which ignites a corona discharge. -The device.