JPS63229882A - Pulsed laser device - Google Patents

Abstract

PURPOSE:To render each circuit constant the most adequate, therefore to attain stabilization of discharge and improvement of oscillation effectiveness, and thereby to realize a long pulse oscillation by a method wherein a high voltage generating circuit, which starts discharge, and a discharge maintaining circuit, which maintains discharge, are independently constructed. CONSTITUTION:A high voltage generating circuit 11 of a laser device is composed of a series circuit consisting of a condenser 21 and a resistor 22, which is connected between primary electrodes 3a and 3b, and a series circuit consisting of a condenser 24 and a resistor 23, which is connected in parallel with the former series circuit. Connecting points of resistors 22 and 23 with condensers 21 and 24, which compose the series circuits of the circuit 11, are selectively connected with a trigger gap 25. A series circuit consisting of a saturable reactor 31 and condenser 32, which composes the discharge maintaining circuit, is connected between the primary electrodes 3a and 3b, and the relation of the capacitance C1 of the condenser 32 to the capacitance C2 of the condenser 21 and 24 is so set as to be C1>=C2. By these processes, stabilization of discharge and improvement of oscillation efficiency are attained, therefore a long pulse oscillation is realized and a laser spectrum band can be rendered narrower.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to a pulsed laser device that performs pulsed discharge excitation in a laser gas.

(Prior Art) Laser devices that excite laser gas to perform pulsed laser oscillation include TEACO2 laser devices, excimer laser devices, and metal vapor laser devices.

Halogen gas laser devices and the like are known. Except for those with high output electron beam excitation,7 these generally employ a discharge excitation method.

A conventional pulse laser device employing the discharge excitation method is configured as shown in FIG. 4 or FIG. 5.

That is, the one shown in FIG. 4 has a main electrode 3a,
3b are arranged to face each other, and preliminary ionization electrodes 4a, 4b and 5a, 5b are arranged to face each other near the main electrodes 3a, 3b. and.

The pre-ionization electrodes 4a, 4b and 5a, 5b are connected to a pre-ionization pulse power source (not shown) via a switch (not shown), and the main electrodes 3a, 3b are connected to a charging resistor from a charging power source (not shown) via a trigger gap 6. The capacitor 8 is connected to both ends of the capacitor 8, which is charged via the capacitor 7.

This device first consists of pre-ionization electrodes 4a, 4b and 5.
A preliminary discharge is performed between a and 5b, and then several tens to several t
A trigger signal is given to the trigger gap 6 with a delay of oo ns, and this trigger gap 6 is short-circuited to connect the capacitor 8.
The charges stored in the main electrodes 3a and 3b cause a glow discharge between the main electrodes 3a and 3b, thereby causing pulsed laser oscillation.

On the other hand, the one shown in FIG. 5 is called an automatic pre-ionization type in which a single power source is used for both pre-discharge and main discharge. Commonly connected to the output end and the main electrode 3a
and pre-ionization electrodes 4b, 5b are commonly connected to one end of a capacitor 9 for starting discharge, and the other end of this capacitor 9 is connected to the main electrode 3b.

In this device, the trigger signal triggers the trigger gap 6.
By short-circuiting the capacitor 8, the capacitor 9 is charged through the pre-ionization electrodes 4a, 4b and 5a, 4b, thereby pre-discharging and charging the capacitor 9. When the capacitor 9 is sufficiently charged, Main electrode 3a.

The main discharge is caused between 3b and 3b.

However, the conventional pulse laser device configured as described above has the following secondary problem. In other words, in order to efficiently perform laser oscillation and stabilize the discharge, it is possible to apply a fast-rising voltage between the main electrodes to speed up the rise of the discharge, and to maintain the discharge stably after the discharge has started. It is necessary to reduce the applied voltage to this level. Furthermore, in order to narrow the laser spectrum, it is necessary to lengthen the discharge time and to lengthen the laser oscillation pulse. but.

When one capacitor 8 or 9 is used as a power source as in the conventional device, it is difficult to satisfy the above three demands. In other words, if the charging voltage of the capacitor 8 or 9 is increased in order to speed up the rise of discharge, the rise of discharge can be made faster, but on the other hand, it is difficult to reduce the applied voltage to a low level at which the discharge can be maintained stably after the start of discharge. Have difficulty. Furthermore, if the capacitance of the capacitor 8 or 9 is increased in order to prolong the discharge time, the time constant 2 will become larger, making it impossible to speed up the rise of the discharge. in this way,
With conventional devices, it has been difficult to satisfy all the conditions required for this type of device.

(Problems to be Solved by the Invention) As mentioned above, in the conventional pulse laser device, the conditions desired for this type of device are: improvement of laser oscillation efficiency, stabilization of discharge, and improvement of laser oscillation. It has been difficult to simultaneously increase the pulse length and narrow the laser spectrum.

Therefore, the present invention can be achieved without complicating the configuration.

It is an object of the present invention to provide a pulse laser device that can satisfy the above-mentioned conditions.

(Means for Solving the Problems) In the present invention, a 7u source for starting a discharge between the main electrodes and a power source for maintaining the discharge are separately provided.

That is, in the first aspect of the present invention, there is provided a pulse laser device including first and second main electrodes that are arranged opposite to each other in a laser gas, and a pre-ionization electrode that promotes discharge between these main electrodes. The main component is a charging power source, multiple capacitors charged by the charging power source, and a switching element that selectively connects each capacitor in series.When the switching element operates, the charging voltage of each capacitor is synthesized. A high voltage generation circuit that applies a voltage at a level between the main electrodes to start discharging between the main electrodes, and a series circuit consisting of a saturable reactor and a capacitor connected between the main electrodes, A discharge sustaining circuit is provided in which the capacitor is charged by the charging power source.

In a second aspect of the present invention, in addition to the above configuration, a circuit for performing automatic operation 6218M is provided.

(Function) A high-voltage, quick-rise pulse voltage is applied between the main electrodes directly from a high-voltage generation circuit or through a circuit for automatic pre-ionization. For this reason.

A fast-rising discharge occurs between the main electrodes. At this time, the high voltage generation circuit and the discharge sustaining circuit are separated by a saturable reactor. When the voltage of the high voltage generation circuit drops below a predetermined level, current flows from the capacitor of the discharge sustaining circuit to the main electrodes through the saturable reactor, and a long-term pulse discharge at a low voltage necessary for sustaining the discharge is performed. in this way.

The high voltage generation circuit is equipped with a high voltage generation circuit that generates the high voltage necessary to start the discharge, and a discharge sustaining circuit necessary to maintain the discharge. A time pulse can be generated, and the discharge sustaining circuit can generate a pulse for a long time at a low voltage necessary for sustaining the discharge.

(Example) An embodiment will be described below with reference to one drawing.

FIG. 1 is a diagram showing a schematic configuration of a pulse laser device according to an embodiment of the present invention. In this embodiment, preliminary ionization is performed using a power source separate from the main discharge power source, and the same parts as in FIG. 4 are indicated by the same reference numerals. Therefore, a detailed explanation of the overlapping portion will be omitted.

This embodiment differs from the conventional one in that a high voltage generation circuit 11 and a discharge sustaining circuit 12 are provided.

The high voltage generation circuit 11 employs a minor circuit configuration.
It is a stage-type impulse voltage generation circuit, and includes a series circuit consisting of a capacitor 21 and a resistor 22 connected between main electrodes 3a and 3b, and a series circuit consisting of a resistor 23 and a capacitor 24 connected in parallel with this series circuit. and a trigger gap 25 inserted to selectively connect the connection points between the resistors and capacitors of each series circuit.

The capacitors 21 and 24 of each series circuit are connected to a high voltage power source for charging (not shown) via a charging resistor 26. Note that 27 in Figure 2 indicates a diode for preventing oscillating current.

On the other hand, the discharge sustaining circuit 12 is configured by connecting a saturable reactor 31 and a capacitor 32 in series between the main electrodes 3a and 3b. Here, the capacitance of the capacitor 32 is C, and each capacitor 21 constituting the high voltage generation circuit 11 is
．． When the capacity of 24 is 02, the relationship is set such that C1≧02.

In addition, 33 in Figure 1 is a peaking capacitor connected between the main electrodes 3a and 3b, and the capacitance of this capacitor is C3.
is set to C3≦C2.

Next, the operation of the pulse laser device configured as described above will be explained.

When the high voltage power supply for charging is turned on, each capacitor 21.24
, 32, 33 are charged to a predetermined level of the polarity shown. In this state, first, the preliminary ionization electrodes 4a, 4b and 5a,
5b is connected to a pulse power source (not shown) to perform preliminary discharge, and then a trigger signal is applied to the trigger gap 25. When a trigger signal is applied, the trigger gap 25
becomes short-circuited, and as a result, a voltage equal to the sum of the voltages charged in the capacitors 21 and 24 is applied between the main electrodes 3a and 3b. Therefore, discharge occurs between the main electrodes 3a and 3b. Note that at this time, no current flows to the capacitor 32 due to the blocking action of the saturable reactor 31. When the output voltage of the high voltage generation circuit 11, that is, the voltage between the main electrodes 3a and 3b decreases to a predetermined level due to discharge between the main electrodes 3a and 3b, current begins to flow from the capacitor 32 via the saturable reactor 31. Then, the saturable reactor 31 is saturated and the inductance is lowered, whereby a low voltage discharge is maintained between the main electrodes 3a and 3b, and long pulse laser oscillation is performed.

In this way, the high voltage generation circuit 11 generates the voltage necessary to start the discharge between the main electrodes 3a and 3b, and the discharge sustaining circuit 12 supplies the energy necessary to sustain the low voltage discharge after the discharge starts. The saturable reactor 31 prevents interference between the two circuits, which is likely to occur when two circuits are installed together. Therefore, on the high voltage generation circuit 11 side, a constant can be freely selected to speed up the rise of the discharge between the main electrodes 3a and 3b, and on the discharge sustaining circuit 12 side, a constant necessary to sustain the low voltage discharge can be freely selected. You will be able to freely choose. For this reason, it is possible to first apply a high-voltage pulse with a fast rise, and then apply the low voltage necessary to maintain the discharge over a long period of time, which ultimately improves the efficiency of laser oscillation, stabilizes the discharge, and oscillates the laser. This makes it possible to achieve longer pulses and narrower laser spectra.

FIG. 2 is a diagram showing a schematic configuration of a pulse laser device according to another embodiment of the present invention. In this embodiment, the present invention is applied to an automatic type (II ionization type). That is, in this embodiment, a resistor 41 is connected between a discharge sustaining circuit 12 and a high voltage generating circuit 11, and The connection point between the resistor 41 and the saturable reactor 31 is commonly connected to the main electrode 3a and the pre-ionization electrodes 4a and 5a, and the pre-ionization electrodes 4b and 5b are commonly connected to the resistor 41 and the high voltage generation circuit 11. A discharge starting capacitor 42 having a much smaller capacity than the capacitors 21 and 24 constituting the high voltage generating circuit 11 is connected to the connection point and between both ends of the discharge sustaining circuit 12.

With such a configuration, if a trigger signal is applied while each capacitor is charged with the illustrated polarity, the trigger gap 25 will be short-circuited and the pre-ionization electrodes 4a, 4 will be short-circuited.
A voltage equal to the sum of the charging voltage of the capacitor 21 and 24 is applied between the capacitor 5a and 5b. For this reason,
Preliminary discharge occurs between the ionization electrodes 4a, 4b and 5a, 5b, and the capacitor 42 is charged to a higher voltage while the preliminary discharge is performed.Then, the charging voltage of the capacitor 42 reaches a predetermined level. Then, main electrode 3
A discharge occurs between a and 3b. At this time, no current flows to the capacitor 32 due to the presence of the saturable reactor 31. When discharge occurs between the main electrodes 3a and 3b, current subsequently flows from the capacitor 32 via the saturable reactor 31, resulting in a transition to low-voltage, long-term discharge. therefore,
The same effects as in the previous embodiment can be obtained, and automatic preliminary discharge can also be performed.

FIG. 3 is a diagram showing a schematic configuration of a pulse laser device according to yet another embodiment of the present invention.

This embodiment is also an example in which the present invention is applied to an automatic pre-ionization type. In the embodiment shown in FIG.

Preliminary discharge is performed when charging the capacitor 42 for starting discharge, but in this embodiment, preliminary discharge is performed twice: when charging the capacitor 42 and when discharging from the capacitor 42. That's what I do. That is, both ends of the resistor 41 are short-circuited, and a capacitor 42 for starting discharge is connected between the pre-ionization electrodes 4b, 5b and the main electrode 3b.

With such a configuration, when a trigger signal is applied in a state where each capacitor is charged to the illustrated polarity, the trigger gap 25 becomes short-circuited and the pre-ionization electrodes 4a, 4
A voltage equal to the sum of the charging voltage of the capacitor 21 and 24 is applied between the capacitor 5a and 5b. For this reason,
Discharge occurs between the preliminary ionization electrodes 4a and 4b and between the electrodes 5a and 5b.
is charged to the polarity shown. Then, when the charging voltage of the capacitor 42 reaches a predetermined level, the pre-ionization electrode 4b,
The main electrodes 3a, 3b pass through the 4a and 5b, 5a.
A discharge occurs between the two. When discharge occurs between the main electrodes 3a and 3b, current subsequently flows from the capacitor 32 via the saturable reactor 31, resulting in a transition to low-voltage, long-term discharge. Therefore, the same effects as in the embodiment described above can be obtained, and sufficient automatic preliminary discharge can be performed.

Note that the present invention is not limited to the embodiments described above. That is, the peaking capacitor 3 in FIG.
3 is not necessarily required. Further, the resistor 41 in FIGS. 2 and 3 may be replaced with an inductance element.

Further, the trigger gap built into the high voltage generation circuit can be replaced with a switching element such as a thyratron or a semiconductor switch. Further, instead of the saturable reactor, a diode for preventing backflow and a high resistance for charging may be connected in parallel. Furthermore, the high voltage generation circuit can be configured with three or more stages instead of a two-stage configuration (and the charging method can also be a series charging method (Marx circuit).
You can also do this. Various modifications can be made without departing from the gist of the water extraction invention.

[Effects of the Invention] As described above, according to the present invention, the high voltage generation circuit for starting discharge and the discharge sustaining circuit for maintaining discharge are provided in separate configurations, so that each circuit Just set the constants optimally.

It is possible to stabilize the discharge and improve the oscillation efficiency, and also to enable long pulse oscillation, making it possible to narrow the laser spectrum.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a pulsed laser device according to one embodiment of the present invention, FIG. 2 is a schematic diagram of a pulsed laser device according to another embodiment of the present invention, and FIG. 3 is a schematic diagram of a pulsed laser device according to another embodiment of the present invention. FIG. 4 and FIG. 5 are schematic diagrams of a conventional pulse laser device, respectively. 2... Laser gas passage, 3a, 3b... Main electrode. 4 a, 4 b * 5 a + 5 b ・
...Preliminary ionization electrode, 11...High voltage generation circuit, 12
...Discharge sustaining circuit, 21°24.32...Capacitor, 31...Saturable reactor, 25...Trigger gap, 33...Peaking capacitor, 42...
・Capacitor for starting discharge.

Claims (6)

[Claims] (1) First and second arranged oppositely in laser gas
In a pulse laser device equipped with a main electrode and a preliminary ionization electrode that promotes discharge between these main electrodes, a charging power source, a plurality of capacitors charged by the charging power source, and each capacitor are selectively connected to each other. A high voltage that is mainly composed of switching elements connected in series with the main electrodes, and when the switching elements operate, a voltage at a level that is a composite of the charging voltages of each capacitor is applied between the main electrodes to start discharging between the main electrodes. It is characterized by comprising a series circuit consisting of a generation circuit, a saturable reactor and a capacitor connected between the main electrodes, and a discharge sustaining circuit in which the capacitor is charged by the charging power source. Pulsed laser equipment. (2) The pulse laser device according to claim 1, wherein the capacitance of the capacitor of the discharge sustaining circuit is set to be larger than the capacitance of the capacitor constituting the high voltage generation circuit. . (3) The pulse laser device according to claim 1, wherein the high voltage generation circuit has a peaking capacitor of small capacity connected between output terminals. (4) First and second arranged oppositely in the laser gas
In a pulse laser device equipped with a main electrode and a preliminary ionization electrode that promotes discharge between these main electrodes, a charging power source, a plurality of capacitors charged by the charging power source, and each capacitor are selectively connected to each other. A high voltage generation circuit mainly consists of a switching element connected in series with the switching element, and outputs a voltage at a level that is a combination of the charging voltages of each capacitor when the switching element operates, and After being charged with the output of the generation circuit, when the charging voltage level reaches a predetermined level, the charge is released between the main electrodes directly or via the pre-ionization electrode to cause discharge between the main electrodes. The battery includes a discharge starting capacitor of small capacity for starting, and a discharge sustaining circuit configured of a series circuit consisting of a saturable reactor and a capacitor connected between the main electrodes, and in which the capacitor is charged by the charging power source. A pulse laser device characterized by: (5) The pulse laser device according to claim 4, wherein the capacitance of the capacitor of the discharge sustaining circuit is set to be larger than the capacitance of the capacitor constituting the high voltage generation circuit. . (6) The pulse laser device according to claim 4, wherein the capacitance of the discharge starting capacitor is set to be smaller than the capacitance of the capacitor constituting the high voltage generation circuit.