JPH0529689A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To enhance an oscillation efficiency by a large output by discharging a capacitor by a voltage inverting and applying circuit, inverting a voltage to a main electrode, generating a spark discharge by a spare ionization electrode at this time, and delaying a discharge current by delay means. CONSTITUTION:Peaking capacitors 33, 34 connected to a main electrode 31 are discharged, a voltage to the electrode 31 is inverted, and a voltage being twice as high as the discharging voltage is applied between the main electrodes 31 and 32. Thus, the capacitors 33-36 are impedance-matched to the electrodes 31, 32, and charging energy is efficiently injected to the electrodes 31, 32. Accordingly, residual charge is eliminated, and energies to be consumed by spare ionization electrodes 37, 38 are reduced. Further, main discharging currents do not flow to the electrodes 37, 38 by a delay of a saturable core 46. Thus, a gas laser oscillator in which a laser is enhanced by a large output in an oscillation efficiency, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in gas laser oscillators such as F ₂ lasers, excimer lasers and TEMACO ₂ lasers.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of an excimer laser of UV light automatic preionization type. Inside the laser tube 1, a pair of main electrodes 2 and 3 are arranged. In addition, these main electrodes 2,
Of the three, the main electrode 2 acts as a cathode and the main electrode 3 acts as an anode. Peaking capacitors 4, 5 and 6, 7 are connected to the main electrodes 2, 3, respectively, and a preionization pin electrode 8 is connected to the peaking capacitors 4, 6 among them.
Further, the peaking capacitors 5 and 7 have a pin electrode 9 for preionization.
Are connected.

On the other hand, a charging power source 10 is provided, a main capacitor 12 is connected to the charging power source 10 via a charging resistor 11, and the peaking capacitors 4 and 5 are connected to the main capacitor 12. A thyratron 13 is connected to the charging power source 10 via a charging resistor 11, and a coil 14 is connected to the thyratron 13 via a main capacitor 12.
Are connected.

With such a configuration, the main capacitor 12 is charged from the charging power source 10 through the charging resistor. When the thyratron 13 is ignited after this charging is completed, the electric charge accumulated in the main capacitor 4 to
7 and at the time of this transition, each preionization pin electrode 8, 9
Spark discharge occurs at. This spark discharge causes preliminary ionization between the main electrodes 2 and 3. When the pre-ionization progresses sufficiently and the voltage of each peaking capacitor 4 to 7 becomes high, the main discharge is generated between the main electrodes 2 and 3.
Thus, the laser excited and oscillated by this main discharge is strengthened by the resonance of the optical resonator (not shown) and output.

FIG. 4 is a block diagram of an XeF laser to which a Bloomline type discharge circuit is applied. Laser tube 15
A pair of main electrodes 16 and 17 are arranged inside the.
The main electrode 16 of the electrodes 16, 17 has a pulse shaping circuit 20 including a plurality of capacitors 18 and coils 19.
Is connected to the other main electrode 17, and a pulse shaping circuit 23 including a plurality of capacitors 21 and coils 22 is also connected to the other main electrode 17. A gap switch 24 is connected to the pulse shaping circuit 20, and a high voltage power supply HV is connected to the pulse shaping circuit 23. The main electrode 1
A charging resistor 25 is connected between 6 and 17.

With such a configuration, the capacitors 21, 18 of the pulse shaping circuits 20, 23 are connected from the high voltage power source HV.
Is charged. When the gap switch 24 is ignited after this charging is completed, the electric charge accumulated in each capacitor 18 of the pulse shaping circuit 20 is discharged, and the voltage applied to the main electrode 16 is inverted. Due to this voltage reversal, a voltage that is approximately twice the charging voltage of the capacitors 18 and 21 is applied between the main electrodes 16 and 17. As a result, a main discharge is generated between the main electrodes 16 and 17, and the laser excited and oscillated by this main discharge is strengthened by the resonance of an optical resonator (not shown) and output.

By the way, in the UV light preionization type laser described above, the head impedance of the circuit from each peaking capacitor 4 to 7 to the main electrodes 2 and 3 is very small and is about the same.
It is 0.3Ω, and the discharge impedance between the main electrodes 2 and 3 is also about 0.3Ω. However, the impedance of the charging side circuit including the main capacitor 12 and the thyratron 13 is about several Ω, which is quite large. As a result, the charges accumulated in the peaking capacitors 4 to 7 are efficiently transferred to the main electrodes 2 and 3, but the main capacitor 12
The residual charges that could not be transferred from the peaking capacitors 4 to 7 to the main electrodes 2 and 3 due to impedance mismatch.
Cannot be efficiently transferred to. Therefore, the oscillation efficiency of the charging energy with respect to the output laser is significantly reduced.

On the other hand, in the Bloomline type laser, the pulse shaping circuits 20 and 23 can be charged directly from the high-voltage power supply HV, and the impedances of the pulse shaping circuits 20 and 23 are small, so that the laser oscillation efficiency is high. Since the pulse shaping circuits 20 and 23 use the coaxial cable and the printed circuit board as the bloom line circuit, only a small amount of charging energy is stored and the laser output becomes small.
In this method, a water condenser may be used to obtain a large amount of energy, but the water condenser is inconvenient to handle and is not suitable for high repetition of laser oscillation.

[0009]

As described above, in the UV light preionization type, the residual charges cannot be efficiently transferred to the main electrodes 2 and 3 due to the impedance mismatch, and the oscillation efficiency of the charging energy for the output laser is greatly reduced. However, in the Bloomline method, only a small amount of charging energy is stored and the laser output becomes small. Therefore, it is an object of the present invention to provide a gas laser oscillation device having a high output and a high laser oscillation efficiency.

[0010]

According to the present invention, a pair of main electrodes arranged to face each other in a gas laser tube, a plurality of capacitors connected to these main electrodes and connected to a power source, and one of these capacitors are provided. An inversion voltage application circuit that discharges the capacitor connected to the main electrode and applies an inversion voltage to one of the main electrodes, and a discharge current due to the inversion of the capacitor that is arranged near the main electrode causes preionization between the main electrodes. A gas laser oscillating device, which is provided with a preliminary ionization electrode and a delay means for delaying the discharge current flowing through the main discharge electrode until the capacitor is reversed, and which is intended to achieve the above object.

[0011]

By providing such means, the capacitor connected to one of the main electrodes of each capacitor is discharged by the voltage inversion applying circuit to invert the voltage with respect to the main electrode. Apply high voltage.
At this time, the preionization electrode arranged in the vicinity of the main electrode causes a spark discharge due to the discharge current due to the reversal of the capacitor, and the delay means delays the discharge current flowing through the main electrode until the capacitor is reversed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an excimer laser of UV light automatic preionization type. Inside the laser tube 30, the main electrode 3
1, 32 are arranged to face each other. The main electrode 31 acts as a cathode and the main electrode 32 acts as an anode.
Peaking capacitors 33, 34 and 35, 36 are connected to the main electrodes 31, 32, respectively. Among the peaking capacitors 33, 34, 35, and 36, the peaking capacitors 33 and 35 and the peaking capacitors 34 and 36 are commonly connected to each other to connect the laser tube 3 to each other.
It is grounded through 0.

Preliminarily ionizing electrodes 37 and 38 are arranged near the main electrodes 31 and 32 of the laser tube 30. One of the electrodes forming the preionization electrodes 37 and 38 is connected in common and then connected to the main electrode 31 and the potential coil 39, and the other electrodes are connected to ballast coils 40 and 41, respectively. The potential coil 39 and the ballast coils 40 and 41 are commonly connected and connected to the thyratron 42.

On the other hand, a charging switching power supply 43 is provided, to which the cathode main electrode 31 is connected via a charging coil 44 and the anode main electrode 32 is connected via a charging coil 45. There is.

Further, from the main electrode 31 to the potential coil 3
A saturable core 46 is connected to the line connecting 9 together. The saturable core 46 is on-controlled by a control circuit (not shown). That is, the saturable core 46 is maintained in the off state until the thyratron 42 is ignited from the start of charging the peaking capacitors 33 to 36 and the voltages of the peaking capacitors 33 and 34 are inverted. Turns on when the voltage reverses. The charging switching power supply 43 is the charging coil 4
4 is connected to the end portion of the main electrode 31 via 4 so that the saturable core 46 is automatically reset by the charging current to each of the peaking capacitors 33 to 36.
Next, the operation of the apparatus configured as described above will be described with reference to the operation timing chart shown in FIG.

When the charging switching power supply 43 is turned on,
From this charging switching power supply 43 to each charging coil 44,
45 through each peaking capacitor 33, 34 and 3
Charging current flows through 5, 36, and each peaking capacitor 3
3, 34 and 35, 36 are charged. In this case, the peaking capacitors 33 and 34 are charged by supplying a charging current through the main electrode 31. Due to this charging, the voltage of each main electrode 31, 32 gradually increases in the positive direction.

After this charging is completed, the thyratron 42
Is ignited, the charges accumulated in the peaking capacitors 33 and 34 are discharged through the preionization electrodes 37 and 38, the ballast coils 40 and 41, and the thyratron 42, respectively. At this time, spark discharge is generated in each of the preliminary ionization electrodes 37 and 38. Further, the voltage of each peaking capacitor 33, 34 is inverted by this electric charge discharge. As a result, a negative voltage is applied to the main electrode 31 of the cathode as shown in FIG. On the other hand, at this time, the charging voltage of each peaking capacitor 35, 36 is applied to the main electrode 32 of the anode,
As a result, a voltage that is approximately twice the charging voltage of the peaking capacitors 35 and 36 is applied between the main electrodes 31 and 32. When the saturable core 46 is turned on when the voltages of the peaking capacitors 33 and 34 are sufficiently inverted,
A main discharge current flows between the main electrodes 31 and 32 to generate a main discharge. Thus, the laser excited and oscillated by this main discharge is strengthened by the resonance of the optical resonator (not shown) and output.

As described above, in the above-described embodiment, the peaking capacitors 33 to 36 are connected to the main electrodes 31 and 32 and the charging switching power source 43, and the peaking capacitor 33 to 36 is connected to the cathode main electrode 31. Since the connected peaking capacitors 33 and 34 are discharged to invert the voltage with respect to the cathode main electrode 31, a voltage that is approximately twice the charging voltage is applied between the main electrodes 31 and 32. Capacitor 33-
The impedance on the 36 side and the impedance on the main electrodes 31, 32 are matched to efficiently inject the charging energy of the peaking capacitors 33 to 36 into the main electrodes 31, 32. As a result, there is no fear of generation of arc discharge due to dumping due to the residual charge. In addition, since the residual charge is eliminated, the energy consumed by the preionization electrodes 37 and 38 is small, the deterioration of the gas laser medium is reduced, and the preionization electrodes 37 and 38 are less consumed. In addition, since the main discharge current does not flow through the preionization electrodes 37 and 38 due to the delay of the saturable core 46, the gas laser medium is not deteriorated more than necessary. Further, since the saturable core 46 is reset by charging the peaking capacitors 33 to 34, it can be applied to high repetition laser oscillation of 1 kHz.

The present invention is not limited to the above-mentioned one embodiment, and may be modified without departing from the scope of the invention. For example, the method of preionization may be a method using UV light by corona discharge or creeping discharge, or a method using high energy rays such as X-rays. In addition to the excimer laser, F ₂
It can be applied to gas lasers such as lasers and TEMACO ₂ lasers.

[0021]

As described above in detail, according to the present invention, it is possible to provide a gas laser oscillator having a large output and a high laser oscillation efficiency.

[Brief description of drawings]

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

FIG. 2 is a timing chart of the device.

FIG. 3 is a block diagram of a conventional device.

FIG. 4 is a block diagram of a conventional device.

[Explanation of symbols]

30 ... Laser tube, 31, 32 ... Main electrode, 33-36 ... Peaking capacitor, 37, 38 ... Pre-ionization electrode, 39
... potential coil, 40, 41 ... ballast coil,
42 ... thyratron, 43 ... charge switching power supply, 4
4, 45 ... Charging coil.

Claims (1)

Claim: What is claimed is: 1. A pair of main electrodes arranged to face each other in a gas laser tube, a plurality of capacitors connected to the main electrodes and connected to a power source, and one of the capacitors. An inversion voltage application circuit that discharges the capacitor connected to the electrode and applies an inversion voltage to one of the main electrodes, and a discharge current due to the inversion of the capacitor, which is arranged near the main electrode, reserves between the main electrodes. A gas laser oscillator comprising: a preionization electrode for generating ionization; and a delay means for delaying a discharge current flowing through the main discharge electrode until the capacitor is reversed.