JPH01246881A - Gas laser oscillating device - Google Patents

Abstract

PURPOSE:To obtain a gas laser oscillating device with a high output power by a method wherein a gas laser medium is blown onto an electrode face of a primary electrode from directions parallel and intersected with the electrode face so as to remove discharge products or negative ions near the electrode face surely and rapidly. CONSTITUTION:A primary electrode 18, composed of a cathode 16 and an anode 17 which are bonded respectively to the opposed faces of supporting plates 14 and 15 electrically insulated from each other, is provided in a discharge tube 13. A fan 21 and wind guides 22 and 23 are provided in the discharge tube 13. The wind guide 22 is formed in such a manner that it is extended along an inner face of the discharge tube 13 so as to enable the gas laser medium to flow in parallel with the faces of the anode 17 and the cathode 16 when the medium flows between the edges of the supporting plates 14 and 15. And, the wind guide 23 is provided penetrating the supporting plate 15 on the anode 17 side and has an opening between the anode 17 and a pre-ionizing electrode 19, and the gas laser medium is sent from a direction intersected with the electrode face of the cathode 16. By these processes, discharge products or negative ions near the surface of the cathode 16 are rapidly removed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) This invention
This invention relates to gas laser oscillation devices such as COz lasers and excimer lasers.

(Prior art) T E in which laser light is output in a direction perpendicular to the discharge
A (transversely excited a)
Pulsed lasers such as tmosphere CO2 lasers and excimer lasers are desirably high in output when applied to various fields, and in order to obtain high output, it is necessary to increase the number of discharge repetitions. A conventional gas laser oscillation device will be described below with reference to FIGS. 4 and 5.

A gas laser medium at a predetermined pressure is sealed in a discharge tube 1 shown in the figure. Inside the discharge tube 1, parallel holding plates 2.3 are provided facing each other at a predetermined interval in the longitudinal direction. These holding plates 2.3 are electrically insulated from the discharge tube 1.

A main electrode 6 is formed on opposing surfaces of the holder 2.3, with a cathode 4 and an anode 5 facing each other at a predetermined distance.

A plurality of pre-ionization electrodes 7, . . . are provided on the left and right sides of the main electrode 6 in the longitudinal direction.
Peaking capacitors 8, . . . are provided in the middle of .

Further, a fan 9 for forcibly circulating the gas laser medium within the discharge tube 1 is provided within the discharge tube 1, and a wind guide 10 is further provided in the direction in which the fan 9 blows air. This wind guide 10 is formed to guide the gas laser medium sent out from the fan 9 between the main electrodes 6, and the sent out gas laser medium is directed between the cathode 4 and the anode 5 as shown by arrow A in FIG. The flow is parallel to each electrode surface.

Furthermore, a heat exchanger 11 is provided within the discharge tube 1 to cool the gas laser medium that has become hot due to discharge.

A high voltage power source 12 for supplying electrical energy between the cathode 4 and the anode 5 is provided outside the discharge tube 1.

Furthermore, a high reflection mirror (not shown) is provided at one end in the longitudinal direction of the discharge tube 1, and an output mirror (not shown) is provided facing each other at the other end to form an optical resonator.

In the gas laser oscillation device configured in this way, a pre-ionization discharge is generated in the pre-ionization electrodes 7, . A main discharge is caused between. This main discharge generates a laser beam, which is amplified between the resonators and reaches a predetermined output, whereby the laser beam is oscillated in a direction perpendicular to the discharge direction.

Here, in the gas laser medium after the preliminary ionization discharge and main discharge are generated, discharge products (such as CCl4 in the XeCl excimer laser) and ions (such as CI-) are mainly generated near the cathode 4.

If the next discharge occurs while such products remain between the main electrodes 6, localized arc discharge will occur and the laser output will drop significantly.

A fan 9 is provided to remove the above-mentioned products from between the main electrodes 6, and the gas laser medium is forcibly circulated in the direction shown by arrow A.

However, when the number of repetitions is increased in order to increase the output, the laser output drops significantly above a certain value. This is because the generated products remain between the main electrodes 6, making it impossible to obtain a stable main discharge. In other words, the flow velocity at the center of arrow A shown in Figure 5 is maximum, and near the electrode surface the flow velocity is close to zero, so discharge products and negative ions remain. Ta.

(Problem to be Solved by the Invention) A commonly used gas laser oscillation device is equipped with a fan having a wind guide to remove products and negative ions between the opposing cathode and anode. Although the above-mentioned products and negative ions are removed by forced circulation of the gas laser medium, there is a problem in that when a certain number of repetitions is exceeded, the laser output drops significantly.

This invention was made in view of the above-mentioned circumstances, and by reliably removing discharge products and negative ions remaining near the electrode surface of the main electrode before the next discharge occurs, it is possible to achieve a high repetition rate and An object of the present invention is to provide a gas laser oscillation device that can obtain high output power.

[Structure of the invention]

(Means for Solving the Problem) This invention includes a gas laser medium having a predetermined pressure sealed in a discharge tube, a main electrode consisting of a cathode and an anode, and a fan circulating the gas laser medium.
A gas laser that is provided with a wind guide that guides the gas laser medium sent by the fan between the main electrodes, a heat exchanger that prevents the temperature of the gas laser medium from rising, and a high voltage power source that supplies electrical energy between the electrode pair. In the oscillation device, the wind guide is a first wind guide that guides the gas laser medium substantially parallel to the discharge surfaces of the cathode and the anode, and a first wind guide that guides the gas laser medium in a direction intersecting the electrode surface of either the cathode or the anode. and a second wind guide.

(Function) The gas laser medium is circulated in a direction approximately parallel to the cathode and anode electrode surfaces by the first wind guide, and together with the second
By blowing the gas laser medium from a direction that intersects the electrode surface of either the cathode or the anode using the wind guide, the discharge products and negative ions near the electrode surface are reliably removed by the time the next main discharge occurs. Can be removed.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

A gas laser medium having a predetermined pressure is sealed inside the discharge tube 13, and two holding plates 14 are placed inside the discharge tube 13.
．． 15 are arranged one above the other and supported in a parallel state with a gap between them. Both holding plates 14 and 15 are electrically insulated from the discharge tube 1.

A cathode 16 and an anode 17 are coupled to the opposing surfaces of these holding plates 14 and 15, respectively, and a main electrode 18
is formed.

Further, a plurality of preliminary ionization electrodes 19, . . . are arranged on the left and right sides of the cathode 16 and the anode 17 in the longitudinal direction, and their base ends are connected to the holding plate 14, 15. Peaking capacitors 20, . . . are provided in the middle of these pre-ionization electrodes 19, .

Furthermore, a fan 21 is provided inside the discharge tube 13. This fan 21 has first and second wind guides 2.
2.23 is provided. The first wind guide 22 is extended along the inner surface of the discharge tube 13 and has a holding plate 14.1.
The gas laser medium is formed to flow between the edges of the gas laser medium 5, and is formed to flow approximately parallel to the electrode surfaces of the cathode 16 and the anode 17, as shown by arrow B in FIG. There is.

Further, the second wind guide 23 is connected to the holding plate 1 on the anode 17 side.
5, and opens between the anode 17 and a preliminary ionization electrode 19 located upstream of the gas flow. As a result, the gas laser medium is emitted from a direction intersecting the electrode surface of the cathode 16, as shown by arrow C in the figure. In other words, the cathode 16
The gas laser medium is sprayed in a direction that intersects the electrode surface.

Further, a heat exchanger 24 is provided between the gas flow downstream side of the main electrode 18 and the fan 21 .

Furthermore, wiring from a high voltage power supply 25 provided outside the discharge tube 13 is connected to the cathode 16 and the anode 1.7.

The gas laser oscillation device configured in this manner not only blows air in a direction parallel to the electrode surface of the main electrode 18 by the first wind guide 22 having a similar structure to the conventional one, but also blows air to the cathode 16 by the second wind guide 23. The cathode 1, which conventionally tends to remain due to air being blown in a direction approximately perpendicular to the electrode surface,
Discharge products and negative ions near the surface of No. 6 can be quickly removed.

In other words, discharge products and negative ions, which often remain particularly in the vicinity of the cathode 16, can be reliably removed by blowing the gas laser medium through the second wind guide 23.

The output obtained in normal operation of a typical gas laser device is shown by a curved line in FIG. Here, when the laser light output is increased by increasing the speed at which the gas laser medium is blown by the fan, the output increases as shown by curve E.

However, when the number of repetitions is further increased, the rate of increase in output decreases, resulting in a significant drop in output as shown by curve F.

This is mainly due to discharge products and negative ions remaining in the vicinity of the cathode 16 of the main electrode 18, and the device in the above embodiment can reliably remove these discharge products and negative ions. Therefore, as shown by curve G in the figure, the number of repetitions can be increased to approximately 1.5 to 2.0 times compared to the conventional method, thereby improving the laser light output.

Note that the present invention is not limited to the above embodiment. For example, the gas laser medium is blown onto the cathode 16 from the direction crossing the electrode surface by the second wind guide 23, but is not limited thereto, and may also be blown onto the anode 17. It also includes a configuration in which independent fans are provided for the first and second wind guides 22 and 23, respectively.

〔Effect of the invention〕

Gas laser oscillation that can reliably and quickly remove discharge products and negative ions near the electrode surface, which were previously difficult to remove quickly, by spraying the gas laser medium from a direction that intersects the electrode surface of the main electrode. equipment can be provided.

[Brief explanation of the drawing]

FIGS. 1 to 3 show an embodiment of this invention,
Fig. 1 is a front sectional view showing the schematic configuration of the gas laser oscillation device, Fig. 2 is a front sectional view near the main electrode, and Fig. 3 is a laser output comparing the repetition rate of the conventional structure and the gas laser oscillation device of the present invention. FIG. 4 and FIG. 5 are conventional examples, and FIG. 4 is a front sectional view of the gas laser oscillation device, and FIG. 5 is a front sectional view of the main electrode. 13...Discharge tube, 16...Cathode, 17...Anode,
18... Main electrode, 21... Fan, 22... First
23...Second wind guide, 24...Heat exchanger, 25...High voltage power supply. Applicant's representative Patent attorney Takehiko Suzue (Figure 1) Figure 2 (Kuririnshifkenpps) Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A discharge tube in which a gas laser medium having a predetermined pressure is sealed, a main electrode consisting of a cathode and an anode installed in the discharge tube to generate a discharge, a fan that circulates the gas laser medium, and the gas laser medium sent by the fan. In the gas laser oscillator device, the wind guide has a wind guide that guides the energy between the cathode and the cathode, a heat exchanger that prevents the temperature rise of the gas laser medium, and a high voltage power supply that supplies electrical energy between the main electrodes. and a first wind guide that guides the gas laser medium approximately parallel to the discharge surface of the anode, and a second wind guide that guides the gas laser medium in a direction that intersects the electrode surface of either the cathode or the anode. Characteristic gas laser oscillation device.