JPH02268475A - Gas laser device - Google Patents

Abstract

PURPOSE:To enable sufficient pre-ionization and to stabilize laser output by providing a mesh electrode body inside a dielectric to pre-ionize a discharge space between a cathode and an anode. CONSTITUTION:When a high voltage power source 5 is operated, discharge produces between a metal line 23 and an edge section of an inner periphery of each opening 9 of a cathode 3, and a discharge space is pre-ionized. Through this proceeding, main stroke produces between the cathode 3 and an anode 4 to carry out laser oscillation. A field strength of main stroke which produces between the edge section of the inner periphery of the opening 9 and the metal line 23 increases, thereby carrying out sufficient pre-ionization. Main stroke and laser output are stabilized in this way.

Description

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

(Prior Art) In general, in a laser device such as a TEACO2 laser or an excimer laser, a cathode and an anode, which constitute a main discharge electrode, are placed in a laser tube containing a gas laser medium, separated from each other and facing each other. By generating a discharge, the gas laser medium is excited to emit laser light.

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

Conventionally, there has been a gas laser device having a structure shown in FIG. 3, which uses a corona electrode to preliminarily ionize a discharge space by fWl. That is, in the figure, reference numeral 1 denotes a laser tube as a closed container, and a gas laser medium containing a mixture of gases such as CO2, N2, and He is housed in the laser tube 1. Further, a pair of holding plates 2 are arranged in the laser tube 1 so as to be spaced apart from each other and facing each other. A cathode 3 and an anode 4 constituting a main discharge electrode are held and fixed on opposing surfaces of each holding plate 2 in an electrically conductive state. These cathode 3 and anode 4 are connected to a high voltage power source 5, and the cathode 3 is grounded.

1 A peaking capacitor 6 for waveform shaping is connected between the pair of holding plates 2, and a fan 7 for circulating the gas laser medium in the direction of the arrow is provided in the laser tube 1, and a heat source is provided upstream of the fan 7. An exchanger 8 is provided.

The cathode 3 is formed of an open metal plate, such as punched metal or mesh, having a large number of openings 9, and a corona electrode 11 as a pre-ionization means is housed inside the cathode 3. This corona electrode 11 is made up of a strip-shaped copper plate 13 provided within a dielectric 12 such as quartz glass or 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 electrical energy is supplied, first the copper plate 1 is
3 and the edge of the inner periphery of the opening 9 of the cathode 3, a corona discharge occurs, thereby pre-ionizing the discharge space between the cathode 3 and the anode 4.

Then, as the prefil ionization of the discharge space progresses, a main discharge occurs between the cathode 3 and the anode 4, and the molecular generated light generated by this main discharge is resonated in an optical resonator (not shown) to oscillate laser light. It turns out.

However, in the corona discharge that occurs between the plane of the copper plate 13 of the corona electrode 11 and the edge portion of the opening 9 of the cathode 3, the electric field strength is not sufficiently high, and the density of pre-ionized electrons in the discharge space also becomes low.

As a result, the discharge space becomes sufficiently pre-ionized, and the main discharge generated between the cathode 3 and the anode 4 becomes unstable, making it impossible to oscillate the laser with a stable output. Something happened.

As described above, the conventional pre-ionization means could not sufficiently pre-ionize the discharge space, so the main discharge between the cathode and the anode was not stable, and the laser output was also unstable. was there.

This invention was made based on the above-mentioned circumstances, and its purpose is to provide a gas laser device that can obtain stable laser output by sufficiently increasing the electric field strength caused by pre-ionization. be.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to solve the above problems, the present invention includes a hermetic container in which a gas laser medium is sealed, and a container provided oppositely in the hermetic container 1. (Both include a pair of main discharge electrodes, a pre-ionization means for pre-ionizing the discharge space between these main discharge electrodes, and an optical resonator that resonates the light generated by molecules in the discharge space caused by the discharge of the main discharge electrodes. In the gas laser oscillation device, the pre-ionization means includes a plurality of openings formed over almost the entire discharge surface of at least one of the main discharge electrodes, and a dielectric material provided on the opposite side of the discharge surface having these openings. The electrode body is formed into a mesh shape.

By doing so, it was possible to pre-ionize the discharge space so that the electric field strength was sufficient.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Incidentally, the same parts as those in the configuration shown in FIG. 3 are given the same symbols and the explanation will be omitted.

That is, the corona electrode 21 as a preliminary ionization means in the present invention is constructed by disposing thin metal wires 23 as an electrode body in a mesh shape within a dielectric body 22 made of a material with a low reading tangent such as coal glass or mica. ing. The metal wire 23 is, for example, a thin piano wire with a diameter of about 0.1 mm.

In the gas laser device having such a configuration, the high voltage power supply 5
When activated, a discharge occurs between the metal wire 23 and the edge portion of the inner peripheral edge of each opening 9 of the cathode 3, and the discharge space is separated by 6fHft. As the preliminary ionization of the discharge space progresses in this manner, a main discharge occurs between the cathode 3 and the anode 4, thereby causing laser oscillation.

By the way, the discharge that occurs between the inner peripheral edge of the opening 9 of the cathode 3 and the metal wire 23 is caused by the discharge occurring between the inner peripheral edge of the opening 9 and the metal wire 23, which are both sharp. The electric field strength of the generated discharge increases. therefore,
Since the pre-fil ionized electron density in the discharge space becomes high and the electrons are sufficiently pre-ionized, 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 compared to a case where the metal wires 23 are simply arranged in parallel. Therefore, the electric field strength increases and the electric field distribution becomes uniform, which also increases the preliminary electric M electron density and stabilizes the laser output.

In the above embodiment, the corona electrode was installed on the back side of the cathode, but it may be installed on the back side of the anode. Alternatively, the dielectric material may be formed into a cylindrical shape, and the metal wire may be housed inside the dielectric material.

[Effects of the Invention] As described above, the present invention uses a mesh-shaped electrode body provided within a dielectric body as a pre-ionization means for pre-ionizing the discharge space between the cathode and the anode. Therefore, since it is possible to generate a corona discharge with a stronger electric field strength than the conventional corona electrode with a copper plate provided in the dielectric, the pre-ionized electron density in the discharge space becomes high and is sufficiently pre-ionized, resulting in laser output. can be stabilized.

[Brief explanation 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 a 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, 1... Corona electrode, 22... Dielectric, 3... Metal wire (electrode body)

Claims (1)

[Claims] A sealed container enclosing a gas laser medium, at least a pair of main discharge electrodes provided opposite each other in the sealed container, a pre-ionization means for pre-ionizing a discharge space between these main discharge electrodes, and a pre-ionization means for pre-ionizing the discharge space between the main discharge electrodes; In the gas laser oscillation device, the pre-ionization means includes a plurality of optical resonators that resonate molecularly generated light in the discharge space generated by discharge, and the pre-ionization means includes a plurality of laser beams formed over almost the entire discharge surface of at least one of the main discharge electrodes. 1. A gas laser device comprising: apertures; and an electrode body provided on the opposite side of the discharge surface having these apertures and covered with a dielectric, the electrode body being formed in a mesh shape.