JPH02130979A - Pulse laser oscillator - Google Patents

Abstract

PURPOSE:To reduce the operational load of a switch by a method wherein a part of glow discharge energy is fed from a DC charged condenser while the residual part if fed from another condenser charged through a saturable reactor and the condenser itself to augment the laser output. CONSTITUTION:A switch element 9 is normally opened to charge C8 through the channel of a high voltage power supply 11 - a charge resistor 10 - the condenser (C8) - an inductance 7 - saturable reactor 5 - a charging inductance 3 - ground. Besides, the other condenser Cd13 is charged through the channel of a high voltage power supply 11 - a charge resistor 10 - a rectifying element 14 - Cd13 - ground. The power supply 11 commonly charges the C8 and Cd13 at the same voltage. When the element 9 is closed, the inductance 7 is impressed with the charge voltage of C8 in the inverse polarity to that of the C8 while the charge to the C8 is shifted to a C6 through the inductance 7. The charge to the C6 is pulse-compressed to be shifted to a C12 through the saturated reactor 5. Finally, the total voltage of the C12 and the Cd13 is impressed on the main electrodes 1, 2 so that the glow discharge may be caused to emit laser beams.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a pulsed laser oscillation device, and particularly to a pulsed laser oscillation device.

The present invention relates to its discharge section and power supply configuration.

(Prior art) In discharge excitation type gas lasers, laser oscillation is obtained by generating a spatially uniform glow discharge in the laser gas, but pulsed laser oscillations such as lateral excitation pulsed CO lasers and excimer lasers In the device, since the laser gas pressure is above atmospheric pressure and contains gas components with strong electron adhesion, it is difficult to ignite the glow discharge uniformly. Generally, ionization is performed, but in order to effectively perform preliminary ionization and generate a stable glow discharge, it is necessary to apply a high-speed pulse voltage to the discharge section. As a means for generating high-speed pulse voltage, there is a magnetic pulse compression circuit system using a saturable reactor. FIG. 2 shows a magnetic pulse compression circuit type power supply circuit of a conventional pulsed laser oscillation device (for example, the most advanced excimer laser application technology).

A pair of main electrodes 1.2 are disposed facing each other in a container filled with laser gas, and the main electrode 2 is grounded. A charging inductance 3 and a capacitor Cb4 are connected in parallel between the main electrodes 1 and 2. Capacitor C
b4 constitutes a closed circuit with saturable reactor 5 and capacitor Ct6, and capacitor Ct8 constitutes a closed circuit with inductance 7, capacitor Cs8, and switch element 9. The capacitors C and 8 are connected to the high-voltage power supply 11 via the charging resistor 10, and are constructed by connecting one or more capacitors and inductances in parallel. Further, an optical resonator (not shown) is arranged in the direction perpendicular to the plane of the paper.

The operation of the conventional pulsed laser oscillation device configured as described above will be explained. In the initial state, the switch element 9 is open, and the high voltage power supply 11 - charging resistor 10 - capacitor C, 8 -
The capacitor CBS is charged through the path of inductance 7 - saturable reactor 5 - charging inductance 3 - ground. When switch element 9 is closed, capacitor 0
Since the potential on the switch element 9 side of 88 is the ground potential,
It is applied to the inductance 7 with the opposite polarity to the voltage charged in the capacitor 088. As a result, the charge on the capacitor cI18 is transferred to the capacitor Ct6 via the inductance 7. The potential of the capacitor cte is applied to the saturable reactor 5 in a non-saturated state, but when the potential of the capacitor ct6 increases and reaches the saturation voltage of the saturable reactor 5, the saturable reactor 5 becomes saturated and the inductance rapidly decreases. As a result, the charge stored in the capacitor Ct6 is transferred to the capacitor Cb4 via the saturable reactor 5 in the saturated state.
to charge. If the inductance of the saturable reactor 5 at saturation is made sufficiently small, the current period determined by the closed circuit of the switching element 9-capacitor C, 8-inductance 7-capacitor Ct6, the capacitor Ct6-saturable reactor 5- Since the current period determined by capacitor cb4 is sufficiently small, the current pulse is compressed in time. The voltage of capacitor Cb4 increases and the main type $11,2
When the voltage applied between them reaches the discharge breakdown voltage or higher of the laser gas, a glow discharge is formed between the main electrodes 1 and 2, the laser gas is excited, and the laser beam is directed perpendicular to the plane of the paper by the action of an optical resonator (not shown). It is emitted.

(Problem to be solved by the invention) In such a conventional pulsed laser oscillation device,
The saturation voltage of the saturable reactor 5 needs to be several tens of kV or more. The saturation voltage of the saturable reactor 5 is proportional to the number of turns of the saturable reactor, the saturation magnetic flux density of the magnetic material, and the charging frequency of the capacitor Ct6.For the number of turns of 0, the saturation voltage of the saturable reactor 5 is proportional to the number of turns of the saturable reactor, the saturation magnetic flux density of the magnetic material, and the charging frequency of the capacitor Ct6. Since it is necessary to reduce the inductance at saturation as much as possible, increasing the saturation voltage by increasing the number of turns of the saturable reactor 5 is disadvantageous in terms of operating characteristics. If the cross-sectional area of the polar body of the saturable reactor 5 is increased to increase the saturation magnetic flux density, the shape of the saturable reactor 5 becomes larger, which becomes a factor that increases the inductance of the saturable reactor 5 when it is saturated. Furthermore, when increasing the frequency of charging the capacitor Ct6, the rate of change of the current flowing through the switch element 9 increases, which not only shortens the life of the switch element 9 but also limits the types of switch elements that can be used. becomes.

Therefore, the present invention was proposed to eliminate the above-mentioned drawbacks, and its purpose is to reduce the operating voltage of the saturable reactor, reduce the shape of the saturable reactor, and apply high-speed pulses to the discharge section. It is an object of the present invention to provide a pulsed laser oscillation device that improves laser output and significantly reduces the operational responsibility of a switch.

[Structure of the Invention] (Means for Resolving the Problem) The pulsed laser oscillation device of the present invention connects two capacitors in series between a pair of opposing main electrodes, and grounds the connection point of these capacitors. The first capacitor is connected to a high-voltage power supply via a rectifying element and a charging resistor, a charging inductance is connected in parallel with the second capacitor, and the second capacitor, a saturable reactor, and a capacitor are connected in series to form a closed circuit. The capacitor is connected in series with an inductance, a capacitor, and a switch element to form a closed circuit, and the capacitor is connected to a high-voltage power source via a charging resistor.

(Function) According to the present invention configured as described above, a certain portion of the total electrical energy supplied to the glow discharge is used to charge the second
The remaining energy can be supplied from the first capacitor charged by compressing the pulse through the action of the saturable reactor and capacitor. Therefore, the operating voltage of the saturable reactor can be reduced and the shape of the saturable reactor can be reduced, which not only improves the pulse compression performance but also significantly reduces the operating responsibility of the switching element. Furthermore, since the pulse applied to the discharge section can be made faster, the laser output can be increased, making it possible to provide a pulsed laser oscillation device with a long life and high output.

(Example) An example of the present invention will be specifically described below with reference to FIG.

A pair of main electrodes 1.2 are arranged facing each other in a container filled with laser gas, and main electrode 2 is grounded. A capacitor CP12 and a capacitor Cd1 are connected between the main electrodes 1 and 2.
3 are connected in series, and their connection point is grounded.

Capacitor Cd13 is connected to positive polarity high voltage power supply 11 via rectifying element 14 and charging resistor lO. Further, a charging inductance 3 is connected in parallel with the capacitor CP12. Capacitor C, 12, saturable reactor 5, and capacitor Ct6 are connected in series to form a closed circuit, and capacitor Ct6, inductance 7, capacitor C, 8, and switch element 9 are connected in series to form a closed circuit. is forming. The connection point between the capacitor C, 8 and the switch element 9 is configured to be connected to the high voltage power supply 11 via the charging resistor 10. One or more capacitors and inductances of 0 or more are connected in parallel. ing. Further, an optical resonator (not shown) is arranged in the direction perpendicular to the plane of the paper.

The operation of the pulse laser oscillation device of the present invention configured as described above will be explained. In the initial state, the switch element 9 is open, and the high voltage power supply 11 - charging resistor 10 - capacitor C68
The capacitor C88 is charged through the path of - inductance 7 - saturable reactor 5 - charging inductance 3 - ground. In addition, the capacitor Cd13 is connected to the high voltage power supply 11-
Charging resistor 1〇 - rectifying element 14 - capacitor Cd 13 - charged through the grounding path 0 In the present invention, capacitor Cs
Since the power supply for charging 8 and the power supply for charging capacitor Cd13 are common, capacitor C, 8 and capacitor Cd13
are charged to the same voltage. When the switch element 9 is closed, the potential on the switch element 9 side of the capacitors C, 8 becomes the ground potential, so the voltage charged in the capacitors C, 8 is applied to the inductance 7 with the opposite polarity to the charged voltage. As a result, the charge on capacitor 088 is transferred to capacitor Ct6 via inductance 7.

The frequency at which the charges shift is determined by the series capacitance value of capacitor C88 and capacitor Ct6 and the value of inductance 7.

In the process of increasing the terminal voltage of the capacitor Ct6, the voltage of the capacitor Ct6 is discharged from the saturable reactor 5 through the charging inductance 3, but the saturable reactor 5 is in a non-saturated state.

The value of the inductance is very large, and the decrease in the terminal voltage of the capacitor Ct6 is very small. When the potential of the capacitor C16 becomes sufficiently high and reaches the saturation voltage of the saturable reactor 5, the saturable reactor 5 rapidly changes from a non-saturated state to a saturated state, and the inductance of the saturable reactor 5 rapidly decreases. As a result, the charge stored in the capacitor Ct6 is transferred to the capacitors C and 12 via the saturable reactor 5 in the saturated state. If the inductance of the saturable reactor 5 at saturation is made sufficiently small, the switching element 9-capacitor C! 18 - inductance 7 - capacitor Ct6 - capacitor Ct6 - saturable reactor 5 - capacitor Cp
Since the current period determined by 12 is sufficiently small, the current pulse is compressed in time. When the voltage of capacitor CP12 increases and the total value of voltage Vp of capacitor CP12 and voltage Vd of capacitor Cd13 reaches the discharge breakdown voltage between main electrodes 1.2 or higher, glow discharge occurs between main electrodes 1.2. The laser gas is excited and a laser beam is emitted in a direction perpendicular to the plane of the paper by the action of an optical resonator (not shown).

In the following, the characteristics required for the saturable reactor 5 and the switching energy of the switch element 9 in the embodiment of the present invention will be described in detail in comparison with the conventional example. For easy comparison with the conventional example, the capacitance value of capacitor Cb4 is equal to the series capacitance value of capacitors CP12 and capacitor Cd13, and the discharge breakdown voltage Wb between main electrodes 1 and 2 is equal to the voltage VP (negative electrode) of capacitors C and 12. ) and capacitor Cd1
The case where the voltage is equal to the total value (=Vd-Vp) of the voltage Va (positive polarity) of No. 3 will be shown.

Since the operating voltage of the saturable reactor is approximately equal to VP,
The operating voltage can be reduced to about 1/2 compared to the conventional method. Therefore, the cross-sectional area of the magnetic material constituting the saturable reactor 5 can be reduced to about 1/2 of that of the conventional system. As a result, the inductance of the saturable reactor 5 at saturation can be reduced to approximately 1/2 of that of the conventional system, and the speed at which the capacitors C and 12 are charged can be increased. Furthermore, since the operating voltage can be lowered, the electrical insulation strength of the winding of the saturable reactor can be lowered, making it easier to wind the winding tightly around the magnetic material, reducing the inductance when the saturable reactor 5 is saturated. can do. Also, the main f
Assuming that the energy injected between t1iil and 2 is equal to the energy energized by the switch cable 9, the switching energy in the conventional method is Hb=1/2.
In the 0-wire system given by ``CbVb'', the switch element 9
The energy shared by UP = 1/2-cpvp”
Here, let c, = ct = cp, may
The relationship between Eb and Eb is as shown in equation 0.

Cp/Cd EP=Dηγgb... ■Here, if the capacitance values of capacitor CP13 and capacitor Cd14 are equal, Ep=1/2Eb, and the operating energy of switch element 9 in this method is the same as in the conventional method. It drops to 50%. Also, at this time, the voltage value Vp is the voltage Vb of the conventional method.
The operating voltage is also 1/2. Therefore, it is also possible to use a semiconductor switch or the like as the switch element 9.

In the above explanation, capacitor Cs8 and capacitor Cd1
Although the high-voltage power supply 11 connected to 3 is the same, it is also possible to use separate power supplies to vary the charging voltage, and the energy accumulated in the capacitor on the DC charging side and the energy accumulated in the capacitor on the pulse charging side can be changed. By changing the ratio, the operational responsibility of the switch can be set to match the switch being used, and the selection of usable switches can be expanded. In this way, the degree of freedom in circuit configuration is greater than in the conventional system.

〔Effect of the invention〕

According to the present invention configured as described above, a fixed portion of the total electrical energy supplied to the glow discharge is supplied from a DC-charged capacitor, and the remaining energy is pulse-compressed and charged by the action of the saturable reactor and the capacitor. can be supplied from a capacitor. Therefore, the operating voltage of the saturable reactor can be reduced and the shape of the saturable reactor can be reduced, which not only improves the pulse compression performance.

At the same time, the operational responsibility of the switching elements can be significantly reduced. Furthermore, since the pulse applied to the discharge section can be made faster, the laser output can be increased, making it possible to perform pulsed laser oscillation with a long life and high output.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the pulsed laser oscillation device of the present invention, and FIG. 2 is a circuit diagram showing a conventional pulsed laser oscillation device. 1... Main electrode, 2... Main electrode. 3... Charging inductance, 4... Capacitor C
P. 5... Saturable reactor, 6... Capacitor C
t. 7...Inductance, 8...Capacitor Cs
. 9... Switch element, 10... Charging resistor, 11...
- High voltage power supply, 12... Capacitor CP, 13... Capacitor Cd, 14... Rectifier element. Agent Patent Attorney Noriyuki Chika Yudo Ken Daishimaru

Claims (1)

[Claims] In a pulsed laser oscillation device in which a capacitor is connected between a pair of opposing main electrodes, the capacitor is divided into two parts connected in series to a first capacitor and a second capacitor, the connection point of the two parts is grounded, and the A first capacitor is connected to a DC power source via a rectifying element, the second capacitor is connected to a saturable reactor and a third capacitor to form a closed circuit, and the third capacitor is connected to an inductance and a fourth capacitor. A pulsed laser oscillation device characterized in that a closed circuit is formed by connecting a capacitor and a switch element, and the fourth capacitor is connected to the DC power source.