JPH04283976A - Gas laser oscillation device - Google Patents

Abstract

PURPOSE:To enable a discharge product to be discharged outside a location near a discharge portion and a stable pulse discharge to be performed repeatedly by branching from an input/output path near a discharge side of a gas laser medium at a main discharge electrode toward a discharging direction and at the same time forming a discharge path so that it merges circulation. CONSTITUTION:A gas laser medium which flows toward a discharge portion is divided into two parts, namely those passing an input/output path 30 along guide bodies 22 and 23 and those flowing to first paths 28a and 28b after entering through flow entrances 29a and 29b. Flow is rapid since the flow entrances 29a and 29b are wide and the flow is constricted inside in the first flow paths 28a and 28b, thus enabling a flow which is suctioned to a side of the first paths 28a and 28b to be generated at second paths 30a and 30b. The sucked gas merges the gas laser medium passing the discharge portion at a circulation flow path again.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transverse excitation type gas laser oscillation device.

0002

2. Description of the Related Art In a pulsed laser such as an excimer laser or a TEACO2 gas laser oscillator that performs pulse oscillation, the laser output is calculated from the product of the number of joules per pulse and the number of repetitions of pulse oscillation. For this reason, in order to obtain high output, various proposals have been made to increase the number of repetitions of the main discharge. In order to increase the number of repetitions of main discharge, it is important to remove discharge products generated during main discharge and negative ions that remain on the electrode surface of the discharge electrode far outside the discharge space, and this removal is effective. Even if the number of repetitions is increased without being carried out properly, arc discharge that does not contribute to laser oscillation will occur on the discharge side of the gas laser medium in the discharge section. Figure 5 is Japanese Patent Publication No. 1-24688.
This is one of the proposals related to the above proposal disclosed in Publication No. 1. In other words, two holding plates (2) and (3) are placed parallel to each other at a predetermined distance within a discharge tube (1) in which a gas laser medium is sealed at a predetermined pressure, and an electric current is applied to the discharge tube (1). They are placed one above the other in an insulated state. Holding plate (
A long cathode (4) and an anode (5) are connected to the facing surfaces of the discharge tube (1) along the axial direction of the discharge tube (1), and these constitute the main discharge electrode. ing. A plurality of pre-ionization electrodes (6) are arranged at a predetermined pitch on the left and right sides of the cathode (4) and anode (5), respectively, on the holding plate (2).
), (3) are provided above. Each pre-ionization electrode (6
) A peaking capacitor (7) is provided in the middle of each. Furthermore, a fan (8) for circulating the gas laser medium and a heat exchanger (9) are provided in the discharge tube (1).
) are provided for guiding the wind generated between the main discharge electrodes. The first wind guide (10) extends along the inner surface of the discharge tube (1), and as shown by arrow A, the gas laser medium passes between the edges of the holding plates (2) and (3). , the cathode (4), and the anode (5). On the other hand, the second wind guide (11) passes through the holding plate (3) on the anode (5) side and has an opening between the anode (5) and the preionization electrode (6) located upstream of the gas flow. As shown by arrow B, the gas laser medium is caused to flow in a direction intersecting the electrode surface of the cathode (4).

0003

[Problem to be solved by the invention] In the above configuration, the arrow A
Since the flow shown by arrow B intersects with the flow shown by arrow B, depending on the state of each flow, the flow is disturbed just before it enters the discharge space, and discharge products and negative ions are expelled further from the discharge space. There were times when this became difficult. Also, the second wind guide (11) is eliminated and the first wind guide (
When flowing the gas laser medium only with 10), the fan (8)
Although effective removal becomes possible by increasing the air volume by making the device larger, this goes against the desire to make the device as small as possible.

The present invention has been made in view of the above circumstances, and provides a gas laser oscillation device that can increase the number of pulse oscillation repetitions and increase the output of the laser without increasing the size of the blowing means such as a fan. The purpose is to provide. [Structure of the invention]

[0005]

[Means for Solving the Problems] An airtight container in which a gas laser medium is sealed at a predetermined pressure; at least a pair of main discharge electrodes provided to form a main discharge space within the airtight container; A circulation means for circulating the gas laser medium in the airtight container, a guide body forming an input/output path for guiding and discharging the circulated gas laser medium between the main discharge electrodes, and an input/output path near the discharge side of the gas laser medium in the main discharge electrode It is characterized by comprising a discharge passage which is formed to branch from the outlet passage in the discharge direction and join the circulation.

[0006]

[Operation] The discharge products that tend to stay due to the vortex generated near the discharge side of the gas laser medium of the electrode are instantly discharged outside the vicinity of the discharge section.

[0007]

[Embodiment] Hereinafter, an embodiment will be explained based on the drawings. FIG. 1 shows an enlarged view of a discharge portion and its vicinity in an embodiment of the present invention. That is, the holding plate (20
), (21), and on their mutually opposing surfaces there is a guide body (22) which has almost the same shape and is a molded body of fluororesin.
, (23) are provided symmetrically. Guide body (2
2) and (23) have a gentle mountain-like cross section;
As shown in FIG. 2, it is long in the tube axis direction, which is perpendicular to the plane of the paper, and the top portions (22a) and (23a) and the main body (
22b). (23b) It is formed into a divided body divided into two parts. A cathode (24) with long grooves formed in the top portions (22a) and (23a) and constituting the main discharge electrode.
and an anode (25) are buried respectively. Also,
The main bodies (22b), (23b) are provided with a plurality of pin electrodes (26a), which form one side of the pre-ionization electrodes, which are provided through the top portions (22a), (23a) at a predetermined pitch, as shown in FIG. , (26b), respectively, are buried therein. In addition, inside the main bodies (22b) and (23b), there is a first passage (28) in the form of a slit, which is slightly narrower than the width in the longitudinal direction.
a) and (28b) are formed. The first passages (28a), (28b) have large inflow ports (29a), (29b) on the inflow side of the gas laser medium into the discharge section.
is formed. In addition, the first passage (28a), (
28b) A plurality of small hole-shaped second passages (30
a) and (30b) are the top portions (22a) and (30b), respectively.
23a) and the main body (22b). (23b) through
The top portions (22a) and (23a) are formed to be open on the discharge side from the discharge section of the gas laser medium. Here, the entrance/exit path (28a), (28b) side is formed by the guide bodies (22), (23).
The discharge part 31) is formed so that the pressure during circulation is lower than that in the discharge part 31).

Next, the operation of the above structure will be explained. That is, the gas laser medium flowed toward the discharge section by a circulation means (not shown) flows through the guide bodies (22), (23).
The one that passes through the inlet/outlet (30) along the inlet and the inlet (2)
9a), (29b) and the first passage (28a)
, (28b). The first passage (
28a), (28b), the inlet (29a),
Since (29b) is wide, it is narrowed inside and flows at high speed, so that in the second passages (30a) and (30b), a flow is generated that is sucked toward the first passages (28a) and (28b). The sucked gas passes through the first passage (28
a) and (28b), it joins again with the gas laser medium that has passed through the discharge section in the circulation flow path which becomes the discharge side of the discharge section.

FIG. 4 shows another embodiment of the present invention, in which the part corresponding to the first passage in the above embodiment is eliminated, and a discharge passage (35a) having almost the same discharge function as the second passage,
(35b) This is an example in which the following is formed. Discharge path (35a),
(35b) is formed to have a small diameter on the cathode (24) and anode (25) sides, and is in a flow path that expands toward the discharge side. Also in this embodiment, the discharge passages (35a), (35b)
becomes a negative pressure, and the gas laser medium is discharged similarly to the above embodiment.

0010

[Effect of the invention] As explained above, the cathode (24),
Discharge products and negative ions generated by the discharge between the anodes (25) and staying in the vicinity of these electrodes on the discharge side of the gas laser medium instantly flow into the second path (30a), ( 30b) or discharge channel (3
5a), (35b) and merges with the gas laser medium flowing through the inlet/outlet path formed by the guide body, the arc discharge generated on the discharge side of the gas laser passing through the discharge part can be avoided without particularly increasing the gas flow velocity. We were able to eliminate the cause of the discharge. As a result, it became possible to achieve a high repetition rate of stable pulse discharge and increase the laser output.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts showing an embodiment of the present invention.

FIG. 2 is a plan view of essential parts showing an embodiment of the present invention.

FIG. 3 is a sectional view of a main part showing an embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional example.

[Explanation of symbols]

(22), (23)...Guide body, (24)...Cathode, (
25)...Anode, (28a), (28b)...First passage (exhaust passage), (30a), (30b)...Second passage (
(discharge path), (31)...input/output path.

Claims (1)

[Claims] 1. An airtight container in which a gas laser medium is sealed at a predetermined pressure, at least a pair of main discharge electrodes provided to form a main discharge space within the airtight container, and the gas laser medium is enclosed within the airtight container. a circulation means for circulating; a guide body forming an input/output path for guiding and discharging the gas laser medium that has been circulated between the main discharge electrodes; A gas laser oscillation device comprising: a discharge path formed to branch toward the circulation and join the circulation.