JPH0716047B2 - Gas laser equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a gas laser device that emits laser light by exciting a gas laser medium with discharge energy.

(Prior Art) Generally, in a gas laser device such as a TEACO ₂ laser or an excimer laser, a cathode and an anode constituting a main discharge electrode are arranged in a laser tube containing a gas laser medium so as to face _{each other} with a space between them. By generating a discharge, the gas laser medium is excited to emit laser light.

Prior to generating the main discharge between the cathode and the anode,
The space between the cathode and the anode, that is, the discharge space is preionized by the preionization means so that laser oscillation can be performed efficiently. There are various types of preionization means, and one of them is a means for generating a corona discharge using a corona electrode for preionization.

Conventionally, there is a gas laser device having a structure shown in FIG. 3 as a gas laser device for preionizing the discharge space by using a corona electrode. That is, in the figure, reference numeral 1 is a laser tube as a closed container, and a gas laser medium in which a gas such as CO ₂ , N ₂ or He is mixed is contained in the laser tube 1. A pair of holding plates 2 are arranged in the laser tube 1 so as to face each other with a space therebetween. Cathodes 3 and anodes 4 constituting main discharge electrodes are held and fixed on the opposing surfaces of each holding plate 2 in an electrically conductive state. The cathode 3 and the anode 4 are connected to a high voltage power source 5 and the cathode 3 is grounded.

A peaking condenser 6 for waveform shaping is connected between the pair of holding plates 2. Further, a fan 7 for circulating a gas laser medium in the direction of the arrow is provided in the laser tube 1, and heat is exchanged upstream of the fan 7. And a container 8 are provided.

The cathode 3 is formed by an opening metal plate such as a punching metal or a mesh having a large number of openings 9, and a corona electrode 11 as a preionization means is accommodated in the inside thereof. The corona electrode 11 comprises a strip-shaped copper plate 13 provided in a dielectric 12 such as quartz glass or a mica plate, and the copper plate 13 is connected to the high voltage power source 5.

In the gas laser device having such a configuration, when the high voltage power supply 5 is activated and electric energy is supplied, first, the copper plate 13
And corona discharge is generated at the inner peripheral edge portion of the opening 9 of the cathode 3, whereby the discharge space between the cathode 3 and the anode 4 is preionized. Then, when preliminary ionization of the discharge space progresses, a main discharge occurs between the cathode 3 and the anode 4, and the molecule-generated light generated by this main discharge resonates in an optical resonator (not shown) to oscillate laser light. become.

However, since the corona discharge generated between the flat surface of the copper plate 13 of the corona electrode 11 and the edge of the opening 9 of the cathode 3 does not have a sufficiently high electrolytic pole, the preionization electron density in the discharge space also becomes low. Therefore, the discharge space is in a state in which the preionization is not likely to occur sufficiently, so that the cathode 3 and the anode 4
There was a case where the main discharge generated between and became unstable and laser oscillation could not be performed with a stable output.

(Problems to be Solved by the Invention) As described above, since the conventional preionization means cannot sufficiently preionize the discharge space, the main discharge between the cathode and the anode is not stable, and The laser output was sometimes unstable.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas laser device capable of obtaining a stable laser output by sufficiently increasing the electrolytic strength by preionization. is there.

[Structure of the Invention] (Means and Actions for Solving the Problems) In order to solve the above problems, the present invention relates to a hermetically sealed container in which a gas laser medium is sealed, and at least a pair of opposed containers provided in the hermetically sealed container. Gas laser oscillation including a main discharge electrode, a preionization means for preionizing the discharge space between the main discharge electrodes, and an optical resonator for resonating the molecule-generated light in the discharge space generated by the discharge of the main discharge electrode In the device, the preionization means is provided with a plurality of openings formed over substantially the entire discharge surface of at least one of the main discharge electrodes, and is provided on the opposite side of the discharge surface having these openings and is covered with a dielectric. An electrode body is provided, and the electrode body is formed in a mesh shape.

By doing so, the discharge space can be preionized so as to have a sufficient electric field strength.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same parts as those in the configuration shown in FIG.

That is, the corona electrode 21 as the preionization means in the present invention has a thin metal wire 23 as an electrode body in a dielectric 22 made of a material having a small dielectric loss tangent such as coal glass or mica.
Are arranged in a mesh shape. The metal wire 23 is
For example, a thin piano wire with a diameter of about 0.1 mm is used.

In the gas laser device having such a configuration, the high voltage power source 5
Is activated, the openings 9 of the metal wire 23 and the cathode 3 respectively
A discharge is generated between the inner peripheral edge portion of and the discharge space, and the discharge space is preionized. Then, when the preliminary ionization of the discharge space progresses in this way, a main discharge is generated between the cathode 3 and the anode 4, thereby causing laser oscillation.

By the way, the edge portion of the inner peripheral edge of the opening 9 of the cathode 3 and the metal wire
The electric field strength of the electric discharge of the electric discharge generated between the metal wire 23 and the edge portion of the inner peripheral edge of the opening 9 is sharp. Therefore, the density of the preionized electrons in the discharge space is increased and the preionization is sufficiently performed, so that the main discharge generated between the cathode 3 and the anode 4 is stabilized, and the laser output is also stabilized.

Moreover, since the metal wires 23 of the corona electrode 21 are provided in a mesh shape, the area facing the cathode 3 is increased as compared with the case where the metal wires 23 are simply arranged in parallel. Therefore,
Since the electric field intensity increases and the electric field distribution becomes uniform, the preionization electron density also increases and the laser output is stabilized.

In addition, although the case where the corona electrode is installed on the back surface side of the cathode has been described in the above-mentioned embodiment, it may be installed on the back surface side of the anode. Further, the dielectric may be formed in a tubular shape and the metal wire may be housed inside.

[Effect of the Invention] As described above, according to the present invention, as the preionization means for preionizing the discharge space between the cathode and the anode, the one in which the mesh electrode body is provided in the dielectric is used. Therefore, since it is possible to generate a corona discharge having a stronger electric field strength than the conventional corona electrode in which the copper plate is provided in the dielectric body, the preionization electron density in the discharge space is increased and the preionization is sufficiently performed, and the laser output is Can be stabilized.

[Brief description of drawings]

FIG. 1 is a sectional view of a gas laser device showing an embodiment of the present invention, FIG. 2 is a perspective view of the same corona electrode, and FIG. 3 is a sectional view of a conventional gas laser device. 1 ... Laser tube (closed container), 3 ... Cathode, 4 ... Anode, 5 ... High-voltage power supply, 21 ... Corona electrode, 22 ... Dielectric material, 23 ... Metal wire (electrode body).

Claims (1)

[Claims] 1. A closed container enclosing a gas laser medium, at least a pair of main discharge electrodes provided in the closed container so as to face each other, and preionization means for preionizing a discharge space between the main discharge electrodes. In a gas laser oscillator comprising an optical resonator that resonates the molecule-generated light in the discharge space generated by the discharge of the main discharge electrode, the preionization means covers substantially the entire discharge surface of at least one of the main discharge electrodes. A gas laser comprising a plurality of openings formed and an electrode body provided on the opposite side of the discharge surface having these openings and covered with a dielectric, wherein the electrode body is formed in a mesh shape. apparatus.