JPH0786671A - Gas laser device - Google Patents

Abstract

PURPOSE:To provide a gas laser device capable of decreasing an attenuation amount of X-rays reaching a discharge space part when the discharge space part is preliminarily ionized by X-rays from an X-ray tube. CONSTITUTION:This embodiment relates to a gas laser device comprising a laser tube 31 sealing a gas laser medium; a totally reflecting mirror and an output mirror 38 forming an optical oscillator provided on one end side and another end side of this laser tube; a pair of main electrodes 32, 33 provided apart to a direction crossing the optical shaft direction within this optical oscillator; and preliminary ionizing means for preliminarily ionizing a discharge space part prior to igniting a main discharge for a discharge space part 34 between these electrodes. The preliminary ionizing means comprises an X-ray tube having a window member 44 for emitting X-rays of which an outer face is formed on a reflection face 44a, and in this X-ray tube, a reflection face of the window member forms a totally reflecting mirror or an output mirror of the optical oscillator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device which excites a gas laser medium by discharge to generate laser light.

[0002]

_2. Description of the Related Art In a gas laser apparatus such as an excimer laser and a CO ₂ laser, a main discharge is ignited between a pair of main electrodes arranged in a laser tube to discharge a gas laser medium. Prior to excitation, the gas laser medium is preionized. There are various means for preionization, and one of them is a preionization means using X-rays.

3 and 4 show a conventional gas laser device using X-rays as a preionization means, respectively. That is, the gas laser device shown in FIG. 3 is provided with the laser tube 1. A total reflection mirror-2 and an output mirror-3 that form an optical resonator are provided in an airtight state on one end side and the other end side of the laser tube 1 in the axial direction.

A pair of main electrodes 4, 5 are arranged between the pair of mirrors 2, 3 at a predetermined interval in a direction intersecting the axial direction of the laser tube 1. As a result, a discharge space 6 is formed between the pair of main electrodes 4 and 5.

The main electrodes 4 and 5 are connected to a high voltage power source 7. When a high voltage is applied to the pair of main electrodes 4 and 5 by the high voltage power supply 7, a discharge is ignited in the discharge space portion 6 between these electrodes.

On one of the main electrodes 4, a concave portion 8 opened to the back side is formed over substantially the entire length in the length direction, whereby a thin portion 9 is formed on the main electrode 4. An X-ray generator 10 is arranged on the back side of the main electrode 4 facing the thin portion 9. This X-ray generator 10 is provided with a plurality of X-ray tubes inside and X-rays from each X-ray.
A window member 11 that emits a line is provided.

The X-ray emitted from the window member 11 passes through the thin portion 9 of the main electrode 4 and irradiates the discharge space portion 6 between the pair of main electrodes 4 and 5. As a result, the discharge space 6 is preionized by X-rays. That is, the discharge space 6 is preionized by the X-ray generator 10 before the main discharge is ignited between the pair of main electrodes 4 and 5.

However, if the discharge space 6 is preionized by X-rays from the back side of the main electrode 4,
X having a size that extends over substantially the entire length of the main electrode 4 in the length direction.
Since the X-ray generator 10 is required, the X-ray generator 1
Not only does 0 increase in size, but the amount of X-rays generated may increase.

Moreover, the X-rays emitted from the X-ray generator 10 pass through the window member 11 and the thin portion 9 of the main electrode 4. Since the attenuation amount of the X-ray increases according to the thickness of the substance to be transmitted as indicated by the curve A in FIG. 5, the attenuation amount is large by transmitting the two members of the window member 11 and the thin portion 9. Therefore, the amount of X-rays generated must be increased accordingly.

In the configuration shown in FIG. 4, one X-ray tube 20 is arranged as an X-ray generator on the back side of the total reflection mirror-2 provided on one axial side of the laser tube 1. This X-ray tube 20
A window member 15 is provided on one end surface in the tube axis direction, and an anode 16 and a cathode 17 are provided separately in a direction intersecting the tube axis direction. The X-rays generated from the X-ray tube 20 pass through the window member 15 and the total reflection mirror-2 and enter the discharge space 6 between the pair of main electrodes 4 and 5, and the discharge space 6 is preionized. To do.

With such a configuration, the discharge space 6 can be preionized by one X-ray tube 20 as an X-ray generator, so that the X-ray generator can be used as compared with the configuration shown in FIG. It is possible to make it compact and to preionize the entire discharge space 6 with a small amount of X-ray generation.

However, since X-rays generated by the X-ray tube 20 are transmitted through the window member 15 and the total reflection mirror-2, the X-ray attenuation amount is the same as in the conventional example shown in FIG. Can be increased, and to avoid it, X
The power input to the wire tube 20 must be increased.

[0013]

As described above, the conventional X
When the X-ray generator is miniaturized and the X-rays from the generator are introduced into the discharge space between the pair of main electrodes, the X-rays are generated by the window member of the X-ray tube and the mirror of the optical resonator. Since it is necessary to pass through one member, the amount of attenuation may increase.

The present invention has been made based on the above circumstances, and an object thereof is to downsize an X-ray generator and introduce it into a discharge space between a pair of main electrodes with a small amount of attenuation. It is an object of the present invention to provide a gas laser device capable of performing the above.

[0015]

In order to solve the above problems, the present invention provides a laser tube in which a gas laser medium is enclosed, and one end side and the other end side of the laser tube. A total reflection mirror and an output mirror forming an optical resonator, a pair of main electrodes provided in the optical resonator in a direction intersecting the optical axis direction, and a discharge between the main electrodes. In a gas laser device provided with a preionization means for preionizing the discharge space portion prior to igniting a main discharge in the space portion, the preionization means emits X-rays and an outer surface is a reflecting surface. An X-ray tube having a window member formed,
This X-ray tube is characterized in that the reflection surface of the window member forms a total reflection mirror or an output mirror of the optical resonator.

[0016]

According to the above construction, the X-ray generated by the X-ray tube is introduced into the discharge space between the pair of main electrodes only by passing through the window member, so that the amount of attenuation can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a gas laser device such as a CO ₂ laser or an excimer laser, and this gas laser device includes a laser tube 31 in which a gas laser medium is enclosed.
Inside the laser tube 31, a pair of main electrodes 32 and 33 are arranged facing each other at a predetermined interval in a direction intersecting the tube axis direction. A discharge space 34 is formed between the pair of main electrodes 32 and 33 to excite the gas laser medium by discharge. That is, the high voltage power supply 30 for applying a high voltage to the pair of main electrodes 32, 33 is connected to the pair of main electrodes 32, 33, and the gas laser in the discharge space 34 is generated by the main discharge ignited by applying the high voltage. The medium is discharge-excited.

Mouth bodies 35 are projectingly provided on both end surfaces of the laser tube 31 in the tube axial direction. A frame-shaped mounting plate 36 in which a through hole 36a is formed is hermetically held and fixed by a plurality of mounting screws 37 on the opening end surface of each mouth 35.

An output mirror 38 is airtightly attached to one mounting plate 36 by a holder 39a, and the other mounting plate 3 is attached.
An X-ray tube 41 is attached to 6. That is, the X-ray tube 41 has a tubular tube body 42 as shown in FIG. 2, a ceramic base 43 is attached to the rear end surface of the tube body 42, and a quartz window is attached to the tip surface. The member 44 is attached. The outer surface of the window member 44 is processed into a total reflection surface 44a so as to form a total reflection mirror.

The tube body 42 is made of a material having a coefficient of thermal expansion close to that of the window member 44, for example, Kovar. This prevents the window member 44 from being damaged due to the difference in thermal expansion coefficient between the tube body 42 and the window member 44.

A coil-shaped cathode 45 is provided inside the tube body 41, and a ring-shaped anode 4 is provided on the inner peripheral surface.
6 is provided. To generate X-rays, a negative high voltage pulse is applied to the cathode 45. As a result, thermoelectrons are emitted from the cathode 45, and the thermoelectrons collide with the anode 46 to generate X-rays.

A step portion 4 is formed on the outer peripheral surface of the tip of the pipe body 41.
7 are formed. Then, the X-ray tube 41 is connected to the window member 43.
Is attached to the mounting plate 36, and the holder 39b provided on the mounting plate 36 is engaged with the stepped portion 47 to be mounted. Thereby, the window member 44
The total reflection surface 44a and the output mirror 38 are parallel and spaced apart to face each other to form an optical resonator, and the pair of main electrodes 32 and 33 are arranged in the optical resonator.

On the outer peripheral surface of the X-ray tube 41, the tube body 4
A cooler 47 for cooling 2 is provided. In order to oscillate and output laser light in the gas laser device having such a configuration, first, a negative high voltage pulse is applied to the cathode 45 of the X-ray tube 41 to generate X-rays. .
Since the X-rays pass through the window member 44 of the X-ray tube 41 and enter the discharge space portion 34 of the pair of main electrodes 32 and 33, this discharge space portion 34 is preionized.

As the preionization of the discharge space 34 progresses, the main discharge is ignited between the pair of main electrodes 32 and 33, and the gas laser medium in the discharge space 34 is excited by the discharge and the laser is excited. -The light is emitted. The laser light generated in the optical resonator is repeatedly reflected and amplified by the output mirror 38 and the total reflection surface 44a, and is oscillated and output from the output mirror 38.

Pre-ionization of the discharge space portion 34 is performed by the X-ray tube 41 provided in the optical axis direction. Therefore, since the entire discharge space 34 can be preionized by one X-ray tube 41, it is not necessary to provide a plurality of X-ray tubes as in the case of preionizing the discharge space 34 from the back side of one main electrode. Therefore, the size of the device can be reduced.

The X-rays generated by the X-ray tube 41 are incident on the discharge space 34 only by passing through the window member 44. In other words, the X-ray is incident on the discharge space portion 34 only by passing through one member, so the amount of attenuation is small. for that reason,
The discharge space 34 can be efficiently preionized.

The present invention is not limited to the above-mentioned one embodiment and can be variously modified. For example, in the above-described embodiment, the outer surface of the window member of the X-ray tube is a total reflection surface and the reflection surface is a total reflection mirror, but it may be formed as a partial reflection surface and used as an output mirror. Well, in short, the window member may be used as either one of the pair of mirrors forming the optical resonator. When the window member is used as an output mirror, if the mouthpiece of the X-ray tube is made of a material that allows laser light to pass therethrough, such as glass, the laser light passes through the window member and the mouthpiece and is emitted. Will be.

When the discharge space is excited from the optical axis direction by the X-ray tube, the X-ray may be emitted from the output mirror together with the laser light. , A total reflection mirror is provided in the optical path of the laser light. Since the laser light is reflected and the X-rays are transmitted to the total reflection mirror, if a lead seal member is provided in the optical path of the X-rays separated from the laser light to absorb the X-rays, It is possible to prevent the line from leaking with the laser light.

[0029]

As described above, according to the present invention, the discharge space is preionized from the optical axis direction by the X-ray tube, and the outer surface of the window member of the X-ray tube is formed as the reflecting surface. Is used as a total reflection mirror or an output mirror of the optical resonator.

Therefore, the X-rays emitted from the X-ray tube preliminarily ionize the discharge space only by passing through the window member.
The discharge space can be efficiently preionized with a small amount of attenuation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a gas laser device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the X-ray tube.

FIG. 3 is a schematic configuration diagram showing a conventional gas laser device.

FIG. 4 is a schematic configuration diagram showing a part of another conventional gas laser device.

FIG. 5 is a graph showing the relationship between the thickness of a substance that X-rays penetrate and the amount of X-rays that penetrate.

[Explanation of symbols]

31 ... Laser tube, 32, 33 ... Main electrode, 34 ... Discharge space part, 38 ... Output mirror, 41 ... X-ray tube, 44 ... Window member,
44a ... Total reflection surface, 45 ... Anode, 46 ... Cathode.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01S 3/097 B

Claims (1)

[Claims] 1. A laser tube enclosing a gas laser medium, and a total reflection mirror and an output mirror forming an optical resonator provided on one end side and the other end side of the laser tube. And a pair of main electrodes provided in the optical resonator so as to be spaced apart from each other in a direction intersecting the optical axis direction, and the discharge space before the main discharge is ignited in the discharge space portion between the main electrodes. In the gas laser device having a preionization means for preionizing the portion, the preionization means is an X-ray tube having a window member that emits X-rays and has an outer surface formed as a reflection surface. A gas laser device in which the reflection surface of the window member of the wire tube forms a total reflection mirror or an output mirror of the optical resonator.