JPH0783150B2 - Power supply for pulse laser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to an improvement of a power supply device used for a pulse laser such as a discharge excitation pulse laser.

(Prior Art) As is well known, a discharge-excited pulsed laser applies a high voltage with a fast rise between a pair of electrodes to cause laser oscillation by utilizing glow discharge of gas between electrodes. However, since this glow discharge turns into an arc in a short time, it is necessary to stop the application of a high voltage rapidly before turning into an arc. In this way, since a pulsed discharge current is induced between the electrodes to cause laser oscillation, it is generally called a pulsed laser. Further, since the discharge pumped pulse laser has a small laser output per pulse, the output is increased by the high repetition operation of several thousand times per second.

FIG. 5 shows an example of a circuit configuration of a power supply device used for this main discharge excitation pulsed laser. In FIG. 5, 1 is a Blum line circuit as a current source that supplies a pulsed current between a pair of electrodes 2, and 3 is a primary winding connected in parallel and a secondary winding connected in series. A capacitor (capacitance C ₁ ) 5 as a voltage source for applying a high frequency voltage to the saturable transformer 4 is a trigger gap for discharging the capacitor 3. In addition, 6 is an adjusting capacitor (capacity) for adjusting the saturation point of the saturable transformer 4.
C ₂ ).

Next, the operation of the discharge excitation pulsed laser power supply device will be described.

First, the bloom line circuit 1 and the capacitor 3 are charged to a predetermined value, and then a pair of electrodes 2 is pre-ionized by using corona, UV light, or X-ray between gaps (not shown). Next, the trigger gap 5 is ignited, and the voltage of the capacitor 3 is applied to the primary winding of the saturable transformer 4 including the adjusting capacitor 6 at high speed (several 10 ns).
Then, in this state, the entire secondary voltage of the saturable transformer 4 in which the secondary windings are connected in series becomes a high voltage twice as high as the charging voltage of the capacitor 3, and is applied between the gaps of the pair of electrodes 2. It As a result, dielectric breakdown occurs between the gaps of the pair of pre-ionized electrodes 2, uniform glow discharge appears, and the impedance between the gaps sharply decreases.
A current begins to flow in the secondary winding of the saturable transformer 4, reaches the saturation point, and the impedance also sharply drops. From the above, a sudden drop in impedance of the pair of electrodes 2 connected between the Blum line circuit 1 and the ground and the saturable transformer 4 acts as a switch, and the Blum line circuit 1 automatically moves to the pair of electrodes 2 A pulsed current will be supplied. Note that FIG. 6 conceptually shows the voltage and current waveforms of the pair of electrodes 2 and the above-described change in impedance.

However, the conventional discharge excitation pulsed laser power supply device having the above-described circuit system has the following problems. That is, since the trigger gap 5 is used as the discharging switch of the capacitor 3, it is practically impossible to perform the repeated operation longer than its electrical life. As an example, the life of the trigger gap 5 is set to 10 ⁸
If the shots are shot 2000 times per second, the trigger gap 5 must be replaced every 14 hours, which is not practical.

(Problems to be Solved by the Invention) As described above, in the conventional pulse laser power supply device, since the voltage source is composed of the capacitor and the trigger gap, the repetition rate is higher than the electrical life of the trigger gap. There was a problem that it was practically impossible to drive.

The present invention has been made to solve the above problems, and an object thereof is to provide a semi-permanent and practical power supply device for a pulse laser capable of improving the life and performing a high repetition operation. To do.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the present invention, a high frequency voltage is applied between a pair of preionized electrodes from a voltage source through a saturable transformer. After applying and glow discharge, in a pulsed laser electrode device to supply a pulsed current from the current source between the electrodes, as the voltage source, a capacitor, a saturable reactor, a semiconductor switch, Further, a magnetic compression circuit for compressing a voltage or current waveform determined by the turn-on time of the semiconductor switch into a predetermined high-frequency waveform and applying it to the saturable transformer is used.

(Operation) In the above pulse laser power supply device, since the magnetic compression circuit composed of the capacitor, the saturable reactor, and the semiconductor switch is used as the voltage source, the voltage or current waveform determined by the turn-on time of the semiconductor switch is used. Since it can be used by compressing into a high-frequency waveform suitable for the load with a magnetic compression circuit, a semiconductor switch with a semi-permanent life can be applied instead of the trigger gap described above. The life of the power supply device can be extended.

(Example) First, the idea of the present invention will be described.

That is, in the present invention, a magnetic compression circuit including a capacitor, a saturable reactor, and a semiconductor switch is used as a voltage source instead of the voltage source formed by combining the capacitor and the trigger gap described above.
This magnetic compression circuit includes a capacitor 7 as shown in FIG.
(Capacitance C ₃ ), 8 (Capacitance C ₄ ), 9 (Capacitance C ₅ ), Saturable reactors 10, 11, 12 and Semiconductor switch 13 Assuming that the inductance of the saturable reactor is indicated, the respective values generally have a relationship as shown in the following equation.

Lsat ₃ > Lsat ₄ > Lsat ₅ (1) C ₃ = C ₄ = C ₅ = C (2) Next, the operation of the magnetic compression circuit 14 will be described.

First, when the capacitor 7 is charged in advance and the semiconductor switch 13 is ignited (conducted), the charge of the capacitor 7 is transferred to the capacitor 8 via the saturable reactor 10 and the saturable reactor 10 is saturated, frequency Then, the voltage of the capacitor 8 rises. Next, capacitor 8
Voltage rises and the current I ₃ with the capacitor 7 decreases, so the saturable reactor 10 shifts to a saturated state with a large impedance, and instead of this, the saturable reactor 11
Is saturated. As a result, the circuit between the capacitors 8 and 9 is reduced via the saturable reactor 11 as in the detailed description, and the charge of the capacitor 7 is transferred one after another.
However, the frequency at this time is calculated from the equations (1) and (2) above. Therefore, the frequency becomes higher as the charge is transferred. In other words, the voltage and current waveforms are compressed. In conditions (1) and (2) here, the peak value of the voltage does not change,
In some cases, the current waveform is compressed and its peak value increases one after another.

In the above magnetic compression circuit, the number of combinations of capacitors and saturable reactors is selected according to various loads, or conversely to the above, Lsat ₃ = Lsat ₄ = Lsat ₅ (4) _{C 3> C 4> C 5} ...... (5) equal to compress the voltage waveforms as may be used in accordance with the purpose. FIG. 3 conceptually shows how the current waveform is compressed and its peak value increases. As described above, the magnetic compression circuit 14 compresses a low-frequency current or voltage waveform into a high-frequency current or voltage waveform suitable for a load.

An embodiment of the present invention based on the above concept will be described below with reference to the drawings.

FIG. 1 shows an example of a circuit configuration of a power supply device for a discharge excitation pulse laser according to the present invention. The same parts as those in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted. Only mention. That is, in FIG. 1, instead of the voltage source formed by combining the capacitor 3 and the trigger gap 5 in FIG. 5, the capacitors 7, 8, 9 described above, the saturable reactors 10, 11, 12, and the semiconductor switch 13 are configured. And compressing the voltage waveform determined by the turn-on time of the semiconductor switch 13 into a high-frequency waveform suitable for the load,
The magnetic compression circuit 14 applied to the saturable transformer 4 is used as a voltage source. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

Next, the operation of the discharge excitation pulsed laser power supply device configured as described above will be described.

First, after charging the Blum line circuit 1 and the capacitor 7 in the magnetic compression circuit 14 to a predetermined value, a spare is made by using corona, UV light or X-ray between the gaps (not shown) between the pair of electrodes 2. Ionize. Next, the semiconductor switch 13 in the magnetic compression circuit 14 is ignited, and the voltage waveform compressed by the magnetic compression circuit 14 is applied to the primary winding of the saturable transformer 4 including the adjusting capacitor 6. Then, in this state, the entire secondary voltage of the saturable transformer 4 in which the secondary windings are connected in series becomes a high voltage and is applied between the gaps of the pair of electrodes 2. As a result, the pair of pre-ionized electrodes 2
A uniform glow discharge is generated due to dielectric breakdown between the gaps, and the impedance between the gaps and the impedance of the saturable transformer 4 are drastically reduced, and the pair connected between the bloom line circuit 1 and the ground is connected. The sudden decrease in the impedance of the electrode 2 and the saturable transformer 4 functions as a switch, and a pulsed current is automatically supplied from the bloom line circuit 1 to the pair of electrodes 2.

Therefore, the discharge excitation pulsed laser power supply device of this embodiment is not limited to having all the functions originally required for the pulsed laser power supply device, and the trigger gap can be used as the conventional voltage supply. First, since the magnetic compression circuit 14 using the semiconductor switch 13 is applied,
It is possible to improve the life of the voltage source and perform high repetition operation, and as a result, it is possible to obtain a semipermanent and practical power supply device for a discharge excitation pulsed laser.

It should be noted that the present invention is not limited to the above-described embodiments, but can be modified in various ways without departing from the scope of the invention.

For example, FIG. 4 shows another embodiment of the power supply device for discharge excitation pulse laser according to the present invention, and the same parts as those in FIG. 1 are designated by the same reference numerals. That is, in the present embodiment, as shown in FIG. 4, a pulse forming network circuit 15 is provided as a current source instead of the above-mentioned bloom line circuit, and the winding method of the saturable transformer 4 is changed as shown in the figure. The matching capacitor 16 is loaded and configured. Even in the discharge excitation pulsed laser power supply device having such a configuration, the same operational effects as the above can be obtained.

[Effects of the Invention] As described above, according to the present invention, a voltage or current waveform that is composed of a capacitor, a saturable reactor, and a semiconductor switch as a voltage source and that is determined by the turn-on time of the semiconductor switch is a predetermined high-frequency waveform. Since the magnetic compression circuit is used for compressing and applying to the saturable transformer, it is possible to provide a semi-permanent and practical pulse laser power supply device capable of improving life and performing high repetition operation.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a discharge excitation pulse laser power supply device according to the present invention, FIG. 2 is a circuit configuration diagram for explaining a magnetic compression circuit applied to the present invention, and FIG. 2 is a current waveform diagram for explaining the magnetic compression circuit in FIG. 2, FIG. 4 is a circuit configuration diagram showing another embodiment of the power supply device for discharge excitation pulse laser according to the present invention, and FIG. 5 is a conventional discharge excitation pulse laser. FIG. 6 is a voltage / current waveform diagram for explaining the operation in FIG. 5, showing the circuit configuration of another embodiment of the power supply device for use in the present invention. 1 ... Bloom line circuit, 2 ... Pair of electrodes, 3 ... Capacitor, 4 ... Saturable transformer, 5 ... Trigger gap, 6 ... Adjustment capacitor, 7,8,9 ... Capacitor, 1
0,11,12 …… Saturable reactor, 13 …… Semiconductor switch, 14 …… Magnetic compression circuit, 15 …… Pulse forming network circuit, 16 …… Matching capacitor.

Claims (1)

[Claims] 1. A high-frequency voltage is applied from a voltage source through a saturable transformer between a pair of pre-ionized electrodes for glow discharge, and then a pulsed current is supplied from a current source between the electrodes. In the pulsed laser power supply device,
A magnetic compression that is composed of a capacitor, a saturable reactor, and a semiconductor switch as the voltage source, and compresses a voltage or current waveform determined by the turn-on time of the semiconductor switch into a predetermined high-frequency waveform and applies it to the saturable transformer. A pulsed laser power supply device characterized by using a circuit.