JPH02240981A - Gas laser device - Google Patents

Abstract

PURPOSE:To enable preionization, uniform and sufficient in intensity, all over a discharge space by providing a plurality of pin electrodes in both longitudinal and cross directions of the electrodes. CONSTITUTION:Insertion through holes 22 are bored and provided in four lines, moreover, in such a way that the neighboring through holes 22 shift their positions in the longitudinal direction of a cathode 21. In respective insertion through holes 22, pin electrodes 15 are insulated with insulated materials 14 and they are maintained by insertion. Consequently, electric discharge takes place between edge parts 17 of the pin electrodes 15 and insertion through holes 22 and then, rays of UV light flow into a discharge space through openings of an aperture metal plate 16. In this way the discharge space is preionized in such a way that ionization is performed sufficiently wide and uniformly and then, such ionization makes main discharge which takes place between the cathode 21 and anode 4 stable and laser output is stabilized.

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) Generally, in a gas laser device such as a TEA CO2 laser or an excimer laser, a cathode and an anode, which constitute a main electrode, are placed in a laser tube containing a gas laser medium and are spaced apart from each other. By generating a main 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 has conventionally had the structure shown in FIG.

That is, numeral 1 in the figure is a laser tube, 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. Each holding plate 2
A cathode 3 and an anode 4, which constitute main electrodes, are held and fixed on opposing surfaces of the main electrodes in an electrically conductive state.

These cathode 3 and anode 4 are connected to a high voltage power source 5, and the anode 4 is grounded.

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. An exchanger 8 is provided.

The cathode 3 has four portions 11 that are open toward the front surface at the center in the width direction and extend over almost the entire length in the longitudinal direction, which is the optical axis direction. Further, in the cathode 3, a plurality of insertion holes 12 are formed in a row at predetermined intervals along the longitudinal direction of the cathode 3, with one end communicating with the four parts 11 and the other end communicating with the back surface of the cathode 3. There is. The other end of each insertion hole 12 communicates with a through hole 13 bored in the holding plate 2. And various through holes 1
A bottle electrode 15 for pre-(i1 ionization), which is electrically insulated by an insulating material 14, is inserted and held in the center of the electrode 2.

This bottle electrode 15 is connected to the high voltage power source 5 via a stabilizing coil 15g.

Further, in the opening of the recess 3B11 of the cathode 3, an open metal plate 16 such as a punched metal plate having a large number of openings 16a is provided.

In a gas laser device with such a configuration, a high voltage electric
When the WL 5 is activated and electrical energy is supplied, electric discharge first occurs between the bottle electrode 15 and the edge portion 17 at the open end periphery of the recess 11 of the insertion hole 12 .

UV light (ultraviolet light) is generated. The UV light passes through the aperture 16a of the aperture metal plate 16 and flows into the space between the cathode 3 and anode 4, that is, the discharge space.
ionize. Pre-(iii) ionization of the discharge space progresses, and the cathode 3
When the voltage between the electrodes 3 and 4 increases, these electrodes 3.
A main discharge occurs between the electrodes 3.4, and laser light is oscillated along the longitudinal direction of each electrode 3.4, which is a direction perpendicular to the discharge direction.

However, in the gas laser device having such a configuration, the bottle electrodes 15 for pre-ionizing the discharge space are only provided in a row at the widthwise center of the cathode 3, so the widthwise center of the discharge space is not sufficiently covered. Reserve 1! Although separated, the parts on both sides are not even ionized. Therefore, the discharge width of the main discharge generated in the discharge space becomes narrow, and the density of pre-ionized electrons in the discharge space cannot be made sufficiently high, so that the main discharge may not be stable and the laser output may also not be stable.

(Problem to be Solved by the Invention) In this way, in the past, only the center portion in the width direction of the discharge space was pre-ionized, which narrowed the discharge width of the main discharge and made it impossible to stabilize the laser output. was there.

The present invention was made based on the above circumstances, and its purpose is to provide a gas laser device that can pre-ionize the entire width direction of a discharge space almost uniformly and with sufficient intensity. There is a particular thing.

[Structure of the invention]

(Means and Effects for Solving the Problems) In order to solve the above problems, the present invention provides a laser tube in which a gas laser medium is sealed, and a laser I; A main electrode consisting of a cathode and an anode arranged as a main electrode, a high-voltage power supply that applies a voltage between the cathode and the anode, and a discharge space prepared before the main discharge that occurs between the cathode and the anode. and a preliminary ionization means for ionizing, the preliminary 71! The separation means has four parts formed open on the surface of at least one of the cathode and the anode, one end of which communicates with the recess, the other end of which communicates with the back surface of the electrode, and four parts that are open in the surface of at least one of the cathode and the anode, and have one end communicated with the recess and the other end with the back surface of the electrode. A plurality of insertion holes are drilled in each of the holes.
Consisting of a pre-ionization bottle electrode that is inserted into the center of each insertion hole while being electrically insulated from the electrode, and openings that are formed in a plate that closes the recess to correspond to the bottle electrodes. do.

By doing so, a large number of bottle electrodes provided in the width direction of the electrodes can uniformly perform the preliminary electric discharge in the width direction.

(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, in this invention, the insertion holes 22 are formed in four rows in the width direction of the cathode 21, and the insertion holes 22 in adjacent rows are formed with their positions shifted in the longitudinal direction of the cathode 21.

Similar to the structure shown in FIG. 3, a bottle electrode 15 is inserted and held in the various through holes 22 while being electrically insulated from the cathode 21 by an insulating material 14.

In the gas laser device having such a configuration, the high voltage power supply 5
When activated, the insertion hole 22 of the bottle electrode 15 and the cathode 21
A discharge occurs between the edge portion 17 of the material and UV light is generated.
The UV light flows through the opening 16a of the apertured metal plate 16 into the discharge space, and this discharge space is pre-ionized. In this way, when the pre-a'Ri separation of the discharge space progresses sufficiently, the cathode 2
A main discharge occurs between the anode 1 and the anode 4, and laser light is oscillated in a direction perpendicular to the direction of the discharge.

Since a large number of the bottle electrodes 15 are provided not only in the longitudinal direction of the cathode 21 but also in the width direction, preliminary ionization by the bottle electrodes 15 can be performed almost uniformly over the entire discharge space. That is, since the discharge space can be uniformly pre-ionized in a sufficiently wide width, the main discharge generated between the cathode 21 and the anode 4 can be stabilized, and thereby the laser output can also be stabilized.

In addition, in the above embodiment, the bottle electrode was provided on the cathode side, but
It may be provided on the anode side, or even on both the cathode and the anode. Moreover, although the bottle electrodes are provided in four rows in the width direction of one electrode, they do not need to be provided in multiple rows regularly, and in short, a large number of rows may be provided in the width direction instead of one row.

[Effects of the Invention] As described above, in the present invention, a plurality of bottle electrodes provided on at least one of the cathode and the anode are provided in both the longitudinal direction and the width direction of the electrode. Therefore, preliminary ionization can be performed uniformly and with sufficient intensity not only in the longitudinal direction of the discharge space but also in the width direction, so that the stability of the main discharge can be improved and the laser output can also be stabilized.

[Brief Description of the Drawings] Fig. 1 is a sectional view of a gas laser device showing an embodiment of the present invention, Fig. 2 is a plan view of a portion of the cathode, and Fig. 3 is a sectional view of a conventional gas laser device. . 1... Laser tube, 4... Anode, 5... High voltage power supply,
DESCRIPTION OF SYMBOLS 11... Recessed part, 12... Insertion hole, 15... Bottle electrode, 21... Cathode. Figure 1 Applicant's agent Patent attorney Takehiko Suzue Figure 2

Claims (1)

[Claims] A main electrode consisting of a laser tube containing a gas laser medium, a cathode and an anode arranged spaced apart and facing each other in the laser tube with the longitudinal direction along the optical axis direction, and a voltage applied between the cathode and the anode. and a pre-ionization means for pre-ionizing the discharge space prior to the main discharge occurring between the cathode and the anode, the pre-ionization means for at least one of the cathode and the anode. A recess formed open on the surface of the electrode, one end communicating with the recess and the other end communicating with the back surface of the electrode, and a plurality of insertion holes drilled in the longitudinal direction and width direction of the electrode, and each insertion hole. It consists of a pin electrode for preliminary ionization inserted into the center of the hole while being electrically insulated from the above electrode, and openings corresponding to the above pin electrodes formed in a plate that closes the above recess. Characteristic gas laser equipment.