JPH0443688A - Gas laser apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application) The present invention relates to a gas laser device that generates laser light by exciting a gas laser medium with a main electrode consisting of a cathode and an anode.

(Prior Art) For example, a gas laser device such as a TEACO2 laser or an excimer laser that emits laser light in a direction perpendicular to the discharge direction is configured as shown in FIG.

That is, numeral 1 in the figure is a tube in which a gas laser medium is housed.

Inside this laser tube 1 are a cathode 2 and an anode 3 that constitute the main electrode.
and (1) and (1) and (2) are arranged facing each other and spaced apart from each other in the downward direction. Upper bin electrodes 5 are provided on both sides of the cathode 2 via peaking capacitors 4, and lower bin electrodes 6 are provided on both sides of the anode 3 opposite to the upper bin electrodes 5.

The above cathode 2, anode 3, upper bottle electrode 5 and lower bottle 7
The 11 poles 6 are each connected to a high voltage power supply 7. When this high-voltage power supply 7 is turned on and electrical energy is supplied between the cathode 2 and anode 3, a discharge occurs between the upper bin electrode 5 and the lower bin electrode 6, and the cathode 2 and anode 3 The discharge space between is pre-ionized. Preparation of the discharge space
When ls M progresses sufficiently, a main discharge (glow discharge) is ignited between the cathode 2 and anode 3, the gas laser medium is excited, and the laser beam is emitted along the axial direction of the laser tube 1, which is perpendicular to the discharge direction. It is designed to be radiated.

Although not shown, a high reflection mirror and an output mirror forming an optical resonator are arranged at both ends of the laser tube 1 in the axial direction. Therefore, the laser light emitted between the cathode 2 and the anode 3 is amplified by the optical resonator, and when it reaches a predetermined intensity, it is oscillated from the output mirror.

Further, a laser heat exchanger 8 is provided.

Conventionally, chang-shaped electrodes as shown in FIGS. 5 and 6 have been used as the cathode 2 and anode 3 to form an equal electric field that stably generates the main discharge. . That is, if the width direction of the electrode 2.3 is X, the longitudinal direction is Y, and the height direction is Z, the cross-sectional shape is
1) Formula Z-v ten k red sjn v-eoshu −
It is determined by equation (2), and thereby an equal electric field can be obtained in the X direction. In each of the above equations, U is the value of the electric force line, k is the parameter that determines the shape, and ■ is the value determined by k, and v -cos-'
(-k) - It can be determined by equation (3).

On the other hand, if the Chan equation is also applied to the X direction, which is the longitudinal direction of the electrode 2.3, the value in the Z direction gradually decreases from the longitudinal center to both ends.
The main discharge ends up being ignited only in the central portion of the electrode 2.3 in the longitudinal direction. Therefore, as shown in Fig. 5, the Z value is usually kept constant over a wide area in the X direction, and the
The end range indicated by `` was set to a chang-shaped shape defined by the above equations (1) and (2). In other words, ``
The dimension indicated by "D" is set to 1/2 of the width dimension of the electrode 2.3 along the X direction, and the curvature m along the X direction of the end thereof is set to be the same as the curvature m along the X direction. was.

However, in such an electrode 2.3, the dimension "D" is very small with respect to the total length in the X direction, so the Z
The directional dimension changes rapidly d.

The electric field was concentrated at a point, making it impossible to obtain a stable glow discharge. For example, the standard value is total length 6
In the case of the 00■ electrode, the Xj dimension of "D" is as small as about 20 mm, and the change in dimension in the Z direction at the do point is rapid, so a large electric field concentration occurs at the d point (7 easy).

When such electrodes 2.3 are used for laser operation, the operation is relatively stable when the voltage applied to these electrodes 2.3 is low, but when the applied voltage is increased, injection into the discharge space increases. When the laser energy is increased, the laser energy may decrease above a certain value, as shown by curve A in FIG. This is due to the electrode 2.
d at the end of 3. This is because the electric field concentrates at a point and arc discharge occurs.

(Problem to be Solved by the Invention) As described above, since the electrodes of conventional gas laser devices have a chang-shaped shape at the ends in the elongated direction as well as in the width direction, the height dimension at the ends There have been cases where the change in the electric field becomes rapid, leading to the occurrence of arc discharge due to electric field concentration.

This invention was made based on the above circumstances, and part 1
-What is the target of 1 at the longitudinal end of the electrode?
An object of the present invention is to provide a gas laser device in which arc group 71i due to LiLi is prevented from being generated.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to solve the above problems, the invention provides a laser tube in which a gas laser medium is housed, and a laser tube that is arranged spaced apart and facing each other in the laser tube. A main electrode consisting of a cathode and an anode, each of which has a cross-sectional shape along the direction that creates a substantially equal electric field in the space facing each other; and a main electrode for supplying electrical energy to the main electrode to excite the gas laser medium. and a high-voltage power supply that generates a main discharge, and at least one of the cathode and the anode has a cross-sectional shape along the longitudinal direction at the longitudinal end thereof having a curved surface that is gentler than the cross-sectional shape along the width direction. It is characterized by being formed.

According to an electrode with such a structure, the change in height at the longitudinal end is gentler than the change in height in the width direction, so arc discharge due to electric field concentration occurs at the longitudinal end. It gets harder.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that the overall configuration of the gas laser device is the same as that shown in FIG.
Since the only difference is the shape from the conventional one, only that shape will be explained.

That is, although the cathode 2 and the anode 3 of the present invention have a chang-shaped cross-sectional shape along the width direction, or the X direction, as in the conventional case, the shape of the end portion 10 in the longitudinal direction, or the Y direction, is , the curvature M along the Y direction is the curvature m' along the width direction
is set smaller than. In other words, the curved surface along the longitudinal direction of the end portion O is set to have a gentler curve than the curved surface along the width direction. As a result, the length E in the Y direction of the end portion 10 where the dimension in the X direction, which is the height dimension, changes is the length E when the same chang-shaped curvature as in the X direction is applied to the end portion as in the conventional case. It can be made longer than D.

The shapes of the end portions 10 of the cathode 2 and anode 3 are set as follows. That is, the length E at the end 10
is set in a range of 5 to 10% of the total length of the electrode 2.3. Then, point E where the XJ law in the X direction begins to change. Y of
The coordinates in the direction and the X direction are (0, 0) and 17, the length E is divided into four equal parts, and each point at that time is E. -E4. Also, E,
The height of the electrode 2.3 at a point (the height at a location other than the end 10 is Z.) [7 Therefore, the coordinates in the Y direction and the X direction at each point E, ~E4 are E. (0・0
)・E・ (-E・Stone Z・)E4 (E, 20 ).

1.,E. - 2 points of E4 by least squares method
Approximate the following -L polynomial. For example, for an electrode with a total length (7 dimensions) of 720 mm and a height (7 dimensions) of 20+++n, if "E" is 10% of the total length, the coordinates of each point (
EO(0,O), El(18,1), E2
(363,3) , El (54,8) , E4
(72, 2°). When this is approximated by a cubic equation using the least squares method, Z −-5,42X 10-2+ 0.113
Y -3,88X 1O-3Y 2+ 8.573
X10-'Y3...Equation (3) is obtained. Therefore, if the cross-sectional shape at E0 to E4 is determined by the above equation (3), the end portion 10 of the electrode 2.3 can be formed into a curved surface that is more gently curved along the Y direction than the Chan shape.

In this way, if the end portion 10 of the electrode 2.3 is formed into a curved surface that is gentler than the width direction, the X
E at the end 10 because the change in direction is also gradual. The electric field becomes difficult to concentrate at a point.

As a result, as shown by the curved line in FIG. 4, higher laser energy can be obtained than in curve A. In other words, the applied voltage is l'i? Even if the electrodes 1 and 2.3 are formed, arc discharge does not occur and the electrodes 2.3 can be formed.

This invention is not limited to the above-mentioned embodiment, and various umbrella shapes are possible. For example, in the above embodiment, 71
Both ends of the i-pole are each larger than the Chan type 4q.
However, the present invention may be applied to only one of the electrodes.

In addition, the cross-sectional shape of the 7-hypole along the width direction is not limited to the Chang shape, but may also be cylindrical, Rogowski-shaped, Ernst 11'/etc. In short, the space that is spaced apart and facing each other within the laser tube is approximately -I' Any shape that provides a shaded electric field may be used.

[Effects of the Invention] As described above, the present invention provides a method in which the cross-sectional shape along the longitudinal direction of at least one of the cathode and the anode is curved more gently than the cross-sectional shape along the width direction. was formed. Therefore, the shape of the end of the electrode changes more slowly in the longitudinal direction than before.
Arc discharge due to electric field concentration is less likely to occur.

[Brief explanation of drawings]

Fig. 1 is a side view of the end of an electrode showing an embodiment of the present invention, Fig. 2 is a perspective view thereof, Fig. 3 is a configuration diagram of a general gas laser device, and Fig. 4 is a voltage applied to the electrode. FIG. 5 is a side view of a conventional electrode, and FIG. 6 is a cross-sectional view along the width direction. 1... Laser tube, 2... Cathode, 3... Anode, 7...
... High voltage power supply, 10... End of electrode.

Claims (1)

[Scope of Claims] A laser tube containing a gas laser medium therein, and a cross-sectional shape along the width direction of the laser tube, which is arranged so as to face each other at a distance, and has a cross-sectional shape along the width direction that creates a substantially equal electric field in the space where the space faces each other. The main electrode includes a formed cathode and an anode, and a high-voltage power supply that supplies electrical energy to the main electrode to generate a main discharge for exciting the gas laser medium. One of the gas laser devices is characterized in that a cross-sectional shape along the longitudinal direction at the longitudinal end portion is formed into a curved surface having a gentler curve than the cross-sectional shape along the width direction.