JPH0245984A - Pulse laser oscillator - Google Patents

Abstract

PURPOSE:To prevent variations in laser oscillation time and to improve a life of an oscillator by connecting an impedance to a spare ionization pin in parallel, by providing an impedance to a main electrode in parallel, and by making discharge conditions between the first pulse and the following pulse the same. CONSTITUTION:Impedances 30A, 30B are connected to a spare ionization pins 9A, 10A and 9B, 10B in parallel and an impedance 31 is connected to main electrodes 7, 8 in parallel. When the impedances 30A, 30B, 31 are inductance in this pulse layer oscillator, a remaining voltage of the main electrodes 7, 8 is discharged at a frequency which is decided by peeking capacitors 11A, 11B, 12A, 12B and the impedances 30A, 30B. Therefore, it is possible to make a remaining voltage 32 disappear before starting of the succeeding pulse discharge by determining the frequency according to operation conditions of the laser oscillator.

Description

[Detailed description of the invention] (Purpose of the invention) (Industrial application field) The present invention relates to a pulsed laser oscillator.

(Prior art) Structure of the discharge section of a conventional pulsed laser oscillator (Unexamined Japanese Patent Publication No. 1983
In FIG. 4, which shows a duct 3 with circular cross-sections of various sizes, inside a cylindrical container 1, there is a blower 4 that circulates the laser gas 5 clockwise in the lower part, and a blower 4 that circulates the laser gas 5 in a clockwise direction. An exchanger 6 is provided, and a main electrode 7 is provided on the central upper outer wall, one end of which is connected to one side of a power source 16 outside the container.
A main electrode 8 is provided facing each other vertically, and pre-ionization pins 9 are provided on the left and right outer walls of this main electrode 7 with one end facing each other vertically.
^, 10^.

and 9B, 10B are attached, and this pre-ionization pin 9A,
The other ends of 10^, 9B, and 10B are connected to one side of peaking capacitors 11^, 12A, 11B, and 1213, and the other side of the upper peaking capacitors 11^ and 11B is connected to one side of the main electrode 7 and power source 16. The other sides of the lower peaking capacitors 12A and 12B are connected to the main electrode 8 and the other side of the power source 16, respectively.

Here, the laser beam in the direction perpendicular to the paper between the main electrodes 7 and 8 is
The ultraviolet rays generated between the preliminary ionization pins 9A, 9B and the IOA, 1o13 are emitted by ionizing the laser gas 2 between the main electrodes 7, 8 and causing a glow discharge 14.

FIG. 5 is a circuit diagram of a pulsed laser oscillator having the structure shown in FIG.
It is boosted by a pulse transformer 19 and charges a capacitor 20 in the first stage of magnetic pulse compression (hereinafter referred to as MPC) on the secondary side. When the charging voltage of this capacitor 20 reaches a certain set value, the saturable reactor 21 of the first stage of MP0 connected in series on the load side rapidly saturates and sends a steep voltage pulse to the capacitor 22 of the second stage of MP0. , and a peaking capacitor 11A in which a voltage pulse with a shorter width is similarly connected in parallel to the main electrode 7.8 on the load side.

Charge 11B, 12A, and 12B.

Then, due to the discharge of these peaking capacitors 11A, 11B and 12A, 12B, the pre-ionization pins 9A, 10^
Between and 98.

Preliminary ionization discharges 13A and 13B occur between main electrodes 7 and 10B, and the laser gas between main electrodes 7 and 8 is ionized, and when the voltage between main electrodes 7 and 8 reaches a discharge starting voltage, a glow discharge 14 occurs.

FIG. 6 shows the temporal changes in these discharges, and shows the gap between the preliminary electrodes 9A and 7.8, which is narrower than the gap between the main electrodes 7.8.

The pre-ionization discharge 25 between 9B and IOA, 108 starts at a low point in the voltage waveform 24 of the discharge section, and after the main discharge starting voltage 26, the voltage drops to the glow maintenance voltage, and the laser beam 28 reaches the main discharge current 27. This occurs after the time point 29 when the flow ends.

However, if the pre-ionization discharge 25 starts at a low point, the time until the main discharge starts 26 will be longer, and not only will ultraviolet rays be emitted and not emit at the main discharge start 26, but the pre-ionization pin will be damaged. This increases the decomposition of the laser gas 2 and shortens the life of the laser device.

Furthermore, when the preliminary ionization discharge 25 starts at a low point, a slight difference in the discharge starting voltage directly causes a variation in the discharge starting time, and as a result, the main discharge starting time 26 also varies.

Furthermore, as shown in Fig. 6), the main discharge voltage 24 remains even after the end of the main discharge 27 (29), so in a laser oscillator that is repeatedly operated, the circuit between the first pulse discharge and the next discharge is determined by the level of this voltage. The conditions are different, the excitation conditions are different, and as above, the output time of the laser beam varies. This becomes a problem in pulsed lasers where output time is important.

Therefore, an object of the present invention is to provide a pulsed laser oscillator that has no variation in laser oscillation output time and can extend its life.

[Structure of the invention]

(Means and effects for solving the problem) The present invention applies a pulse voltage via a magnetic compression circuit to a discharge section in which a peaking capacitor is connected in series to a pre-ionization pin near a main electrode arranged oppositely. In a pulsed laser oscillator that discharges the main discharge, an impedance is connected in parallel between the pre-ionization pins and the main electrode, or a capacitor is connected between the pre-ionization pins to make the discharge conditions of the main discharge the same and the laser oscillation output time This is a pulsed laser oscillator that maintains a constant value and prevents the deterioration of the laser gas, extending its life.

(Embodiment) Hereinafter, one embodiment of the pulsed laser oscillator of the present invention will be described with reference to FIG. However, parts that overlap with Fig. 5 are omitted.

In Figure 1, pre-ionization pins 9A, 10^ and 9B, 1
Impedances 3OA and 30B are connected in parallel to 0B, and impedance 31 is connected to main electrodes 7 and 8 in parallel.

In the pulse laser oscillator configured in this way, when the impedances 30A and 308.31 are inductances, the residual voltage of the main electrodes 7 and 8 is the peaking capacitors 11A, 11B, 12A, and 12B and the impedances 3OA and 30B. By determining this frequency according to the operating conditions of the laser oscillator, it is possible to eliminate the residual voltage 32 before the next pulse discharge starts, as shown in FIG. 2 (2).

In addition, the voltage remaining between the main electrodes 7 and 8 after the glow discharge 14 between the main electrodes 7 and 8 ends is the peaking capacitor 11
^, IIB, 12A, 12B and parallel impedance 30
It is discharged in a time approximately equal to the time constant of the circuit composed of A and 30B.

Note that at this time, there is no discharge V between the pre-ionization pins, and there is no deterioration of the laser gas during this period.

FIG. 3 shows another embodiment.

In Figure 3, between the preliminary electrode pins 9A and IOA and 9B
.

Between 10B and 11A, peaking capacitor 11A, IIB
, 12A.

To capacitor 30 whose capacity is sufficiently larger than 12B.

30B are connected in parallel. The capacitance of the capacitors 30A and 30B is such that the ratio with respect to the peaking capacitor is at least 1/2 or more of the ratio of the reciprocal of the gap between the main electrodes and the gap between the pre-ionization pins.

According to the pulse laser oscillator having such a configuration, the voltage applied between the pre-ionization pins 9A, 10^ and 913, 108 is the peaking capacitor 11A, IIB, 12
^, Since it is determined by the partial voltage between 12B and the capacitor 30A1.30A2, if the capacitor 3OA1.30A2 is sufficiently large, even if the discharge section voltage reaches a sufficient voltage, the voltage between the pre-ionization pins can be reduced, and the voltage between the pre-ionization pins can be reduced until the main discharge. The time can be shortened, and variations in the main discharge start time and decomposition of the laser gas can be prevented.

〔Effect of the invention〕

As described above, according to the pulsed laser oscillator of the present invention, an impedance is connected in parallel to the pre-ionization pin, and an impedance is also provided in parallel to the main electrode to eliminate the residual voltage after the discharge between the main electrodes ends, or A capacitor is connected in parallel to the ionization electrode to shorten the time until the main discharge, making the discharge conditions the same between the first pulse and the next pulse, and making the excitation conditions the same, preventing variations in laser oscillation time and reducing the oscillator. It is possible to obtain a pulsed laser oscillator that can extend the life of the laser.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the pulsed laser oscillator of the present invention, Fig. 2 is an explanatory diagram showing the operation of Fig. 1, and Fig. 3 is a circuit diagram showing an embodiment of the pulsed laser oscillator of the present invention. It is an explanatory view showing the effect of. 7.8... Main electrode 9A, 913. IOA, IOB... Preliminary ionization pins 11A, IIB, 12A, 12B... Peaking capacitor 16... Power supply @ Earthly cow (C) Figure Figure

Claims (2)

[Claims] (1) Consisting of a main electrode provided oppositely to each other, and a peaking capacitor having one side connected to both poles of a pre-ionization pin provided oppositely near the main electrode, and the other side connected in parallel to the main electrode. In a pulsed laser oscillator that excites laser gas by applying a pulse voltage to a discharge part via a magnetic compression circuit, an impedance is provided in parallel to each of the main electrode and the pre-ionization pin to discharge the residual voltage between the main electrodes. A pulsed laser oscillator characterized by: (2) Consists of a main electrode provided oppositely to each other, and a peaking capacitor having one side connected to both poles of a pre-ionization pin provided oppositely near the main electrode, and the other side connected in parallel to the main electrode. In a pulsed laser oscillator that excites laser gas by applying a pulse voltage to a discharge section via a magnetic compression circuit, the capacitance ratio of the peaking capacitor connected in parallel to the pre-ionization pin is equal to the gap between the main electrodes and the reciprocal of the pre-ionization. A pulsed laser oscillator comprising a capacitor having a capacitance of at least 1/2 or more of the ratio of the reciprocal of the gap between the pins.