JPH0555668A - Solid laser equipment - Google Patents

Abstract

PURPOSE:To obtain a solid laser equipment capable of stable and suitable laser working without excess or lack of laser energy, by changing the waveform of pulse energy of pulse laser oscillation by controlling supply energy to a exciting lamp, in a solid state laser. CONSTITUTION:A plurality of subcapacitors 9, a plurality of switching elements 3, 6, 7, 8, and a gate control circuit 12 are added to the conventional power supply for a solid pulse laser. By linking a plurality of the switching elements 3, 6, 7, 8, and performing switching with various combinations, the individual pulse energy waveform of pulse laser oscillation is continuously and arbitrarily changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser device used in industrial equipment and medical equipment and excited by light such as a flash lamp.

[0002]

2. Description of the Related Art Solid-state laser devices are used as industrial equipment in the semiconductor field, such as trimming and scribing, marking, soldering, welding and cutting, and their fields of use are expanding year by year. The expansion of its use is remarkable.

First, a solid-state laser device will be described with reference to the drawings. FIG. 2 shows the configuration of the solid-state laser device. In FIG. 2, 10 is an excitation lamp such as a flash lamp for exciting a laser medium, 15 is a laser medium, and 16 is a reflector for reflecting optical energy (hereinafter referred to as excitation light) (hereinafter referred to as a reflector). , 17 is a partial reflection mirror, 18 is a total reflection mirror, and 19 is a drive power source for the excitation lamp. It should be noted that the reflector 16 is for reflecting the excitation light and efficiently entering it into the laser medium, and has a cylindrical shape in this example, but is not limited to a cylindrical shape.

In the solid-state laser device having such a structure, the pumping light emitted from the pumping lamp 10 is directly or reflected by the reflector 16 and is incident on the laser medium 15 to be absorbed, thereby exciting the laser medium 15 and exciting the laser medium 15. And an optical resonator constituted by a partial reflection mirror 17 and a total reflection mirror 18 arranged on both sides of the partial reflection mirror 17 and the total reflection mirror 18 are brought into a resonance state, and the light is extracted from the partial reflection mirror 17 to the outside.

Next, FIG. 5 shows a circuit configuration of a conventional power source for a solid-state laser. In FIG. 5, 1 is a first inductance that limits the charging current of the capacitor bank 2, 3 is a switching element for controlling the discharge of the capacitor bank 2, and 4 is a second inductor that limits the current flowing into the excitation lamp 10. Inductance, 5 is a diode for backflow prevention, 7
Is a gate signal circuit for controlling the switching element 3, and 11 is a power source for charging the capacitor bank 2.

The operation of the solid-state laser power source configured as described above will be described. In the solid-state laser power supply shown in FIG. 5, the capacitor bank 2 is charged from the charging power supply 11 via the inductance 1. The charging energy of the capacitor bank 2 charged to a constant voltage is supplied to the excitation lamp 10 by the switching element 3. At this time, the energy from the capacitor bank 2 supplied to the excitation lamp 10 is controlled by the gate signal control circuit 7 and supplied for a certain period of time. The energy to the excitation lamp 10 causes the excitation lamp 10 to emit light for a certain period of time, the laser medium 15 is excited as described with reference to FIG.
It is emitted from 7 as a laser beam.

[0007]

In the conventional solid-state laser power supply having the above-described structure, the energy supplied to the excitation lamp 10 is the charging energy of the capacitor bank 2 and is therefore constant over time. The excitation light emitted from the excitation lamp cannot be changed with respect to the time axis. Therefore, when performing laser processing using a solid-state pulsed laser, the energy of laser light cannot be continuously and arbitrarily changed, and the energy (irradiation form) of the laser light with respect to the time axis cannot be arbitrarily changed. However, it is difficult to perform stable laser processing under optimal conditions due to excessive laser energy or insufficient laser energy. Especially in laser welding, laser cutting, etc., unnecessary oxide layers and thermal strain on the surface of the workpiece There was a problem such as the change of quality.

The present invention solves the above-mentioned conventional problems. When performing laser processing using a pulsed laser, the energy (optical waveform) of the pulsed laser light is arbitrarily changed with time to obtain laser energy. It is an object of the present invention to provide a solid-state laser device that enables stable and optimal laser processing without excess or insufficient laser energy, and can reduce deterioration of the surface of a laser-processed product.

[0009]

In order to achieve this object, a solid-state laser device of the present invention comprises a plurality of capacitors (hereinafter referred to as sub-capacitors) and a plurality of switching circuits in addition to a main capacitor (hereinafter referred to as main capacitor). A gate signal circuit for controlling the opening and closing of various combinations is provided by providing a plurality of switching elements in cooperation with each other.

[0010]

According to the above structure, in order to control the charging energy supplied to the excitation lamp, the combination of opening and closing of the plurality of switching elements is rearranged when the energy is supplied to the excitation lamp and when the energy is not supplied. As a result, it is possible to continuously and variously change the energy supplied to the excitation lamp, and it is possible to realize a solid-state laser device capable of continuously and variously changing each pulse energy of pulsed laser oscillation. ..

[0011]

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

FIG. 1 is a circuit diagram showing an embodiment of a laser power source of the present invention used for a solid-state laser device. 1 is a first inductance, 2 is a main capacitor, 3 is a GTO for controlling discharge of the main capacitor. A first switching element such as a thyristor or a transistor, 4 is a second inductance for limiting a lamp inflow current, 5 is a first diode for preventing backflow, and 6 is a second switching element for controlling discharge of the sub-capacitor 9. , 7 and 8 are third and fourth switching elements for switching the current path, and 10
Is a flash lamp used as an excitation lamp, 1
Reference numeral 1 is a charging power source for charging the main capacitor and sub-capacitor, 12 is a gate signal control circuit for controlling the opening and closing of a plurality of switching elements, and 13 and 14 are third and fourth diodes for backflow prevention.

The laser power source configured as described above will be described with reference to FIG. 4 together with FIG.

First, in a state where the first switching element 3 and the fourth switching element 8 are open, the main capacitor 2 operates from the charging power source 11 to the first inductance 1
The charging operation is performed through the following, and the control for continuously changing the electric energy supplied to the flash lamp 10 from this state will be described. In the initial state, all switching elements are in the open state.

[0015] FIG. 4 (a) shows the waveform of the electric energy P _L in the case of reducing the way of feeding the electric energy P _L supplied to the flash lamp 10. In this case, in the circuit of FIG. 1, the first switching element 3 is closed, the charging energy of the main capacitor 2 is supplied to the flash lamp 10 via the first inductance 4, and the gate signal control is performed after an arbitrary set time t _1. In response to a command from the circuit 12, the third switching element 7 is closed, and a part of the electric energy supplied to the flash lamp 10 through the third diode 13 is supplied to the sub-capacitor 9 to the flash lamp 10. Reduce the energy supply of. The amount of decrease in the supplied energy is determined by the capacitance of the sub-capacitor 9 and the size of the second inductance 4. Finally, all the switching elements are opened to stop the supply of energy to the flash lamp 10.

[0016] FIG. 4 (b) shows the waveform of the electric energy P _L in the case of increasing in the course of feeding electric energy P _L supplied to the flash lamp 10. In this case, in the circuit of FIG. 1, first, the fourth switching element 8 is closed, the sub-capacitor 9 is charged, and then the first switching element 3 is closed and the first diode 5 and the second inductance 4 are closed. The charging energy of the main capacitor 2 is supplied to the flash lamp 10 via the. Then, after the arbitrary set time t ₂ , when the second switching element 6 is closed by the command from the gate signal control circuit 12, the energy charged in the capacitor 9 is supplied to the flash lamp 10 and is supplied to the flash lamp 10. Total energy gained. Alternatively, the charging energy of the sub-capacitor 9 may be stored in the flash lamp 10 first.
To the first switching element 3 after a set time t ₂
The same supply energy characteristic as in FIG. 4B can be obtained by closing the. In addition, the first switching element 3
And the third switching element 7 are closed at the same time, a part of the charging energy of the main capacitor 2 is supplied to the sub-capacitor 9, the other part of the charging energy of the main capacitor 2 is supplied to the flash lamp 10, and the set time t ₂ Also by opening the third switching element after
The same energy supply characteristics as in (b) can be obtained. Finally, open all switching elements and flash lamp 10
Stop supplying energy to.

FIG. 4 (c) shows the waveform of the electric energy P _L when the electric energy P _L supplied to the flash lamp 10 is gradually reduced during the feeding. In this case, the first switching element 3 is closed, then the third switching element 7 is closed, then the fourth switching element 8 is closed, the first switching element 3 is opened, and at the same time the second switching element 6 is closed. Realized by Finally, the second switching element 6 is opened to stop the energy supplied to the flash lamp 10.

The opening and closing of the switching element is controlled by the gate signal control circuit 12 according to the time and the order of opening and closing. Thus, the waveform of the electric energy P _L supplied to the flash lamp 10 can be changed by opening and closing the four switching elements shown in FIG. 1 at various times and in order by the signals of the gate signal control circuit 12. it can. In FIG. 4, T represents the pulse width.

Further, as shown in FIG. 3, a switching element 20 for controlling the charging of the main capacitor 2 is added to the circuit of FIG. 1 to utilize the rise or fall of the charging voltage of the main capacitor 2 due to charging and discharging. By
A wider variety of pulse waveforms can be realized, and the processing quality of laser processing by a pulse laser can be improved more effectively.

[0020]

As is apparent from the above invention, according to the present invention, various combinations of switching elements are opened and closed in the sub-capacitors other than the main capacitor, the plurality of switching elements, and the gate signal control circuit. This makes it possible to continuously and variously change the energy supplied to the excitation lamp, and to realize a solid-state laser device that can continuously and arbitrarily change the pulse energy of pulsed laser oscillation. It is possible to suppress the occurrence of unnecessary alteration in the magnetic field and enable good laser processing.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a power supply used in a solid-state laser device of the present invention.

FIG. 2 is a device configuration diagram of the present invention and a conventional solid-state laser device.

FIG. 3 is a circuit diagram showing another embodiment of the power supply used in the solid-state laser device of the present invention.

4A is a pulse waveform diagram in which energy is reduced during energization by the power source of the present invention, FIG. 4B is a pulse waveform diagram in which energy is increased during energization by the power source of the present invention, and FIG. Pulse waveform diagram that energy gradually decreases during energization by the power source

FIG. 5 is a circuit diagram showing a conventional power supply used in a solid-state laser device.

[Explanation of symbols]

 1 1st inductance 2 main capacitor (main capacitor) 3 1st switching element 4 2nd inductance 5 1st diode 6 2nd switching element 7 3rd switching element 8 4th switching element 9 sub Capacitor (second capacitor) 10 Flash lamp (excitation lamp) 11 Charging power supply 12 Gate signal control circuit

Claims (2)

[Claims] 1. A main capacitor, a charging power supply for charging the main capacitor, and a first inductance for limiting a charging current to the main capacitor,
The excitation lamp, the second inductance for limiting the current flowing into the excitation lamp, the first diode for preventing backflow, the main capacitor, the excitation lamp, and the second lamp.
A first switching element that is connected to the first inductance and the first diode for backflow prevention to form a closed circuit to control discharge of electric charge of the main capacitor, and a second capacitor in addition to the main capacitor, A second switching element that is connected to the second capacitor, the excitation lamp, and the second inductance to form a closed circuit to control discharge of the second capacitor, and the first diode via the second switching element. And a second diode connected in parallel for preventing backflow and a third capacitor for controlling charging / discharging of the second capacitor
A series circuit of switching elements, and a third diode for backflow prevention and a second capacitor connected in parallel to the series circuit of the first switching element and the first diode via the second switching element. A solid-state laser device comprising a series circuit of a fourth switching element for controlling discharge and a gate signal control circuit for controlling the four switching elements, and exciting a laser medium by an exciting lamp. 2. The solid-state laser device according to claim 1, further comprising a switching element for opening and closing a charging current to a main capacitor.