JPH08321651A - Solid laser - Google Patents

Abstract

PURPOSE: To conduct a waveform control with higher accuracy and rich in varieties to make it possible to perform a processing on a work on the optimum pressing conditions by realizing wherein the strict control of a pulse, that is, the high-speed control of a pulse. CONSTITUTION: In a solid laser which excites atoms in a solid laser active medium 6 by irradiating the medium 6 with light from an excitation light source 8 to generate a laser beam, the light source 8 is formed of a plurality of semiconductor lasers and at the same time, an output control part for controlling the output of each semiconductor laser is provided.

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 capable of irradiating a workpiece with a laser beam to perform processing such as drilling, cutting, welding and soldering, and particularly, pulse control at high speed. The present invention relates to a solid-state laser device that can be used.

[0002]

2. Description of the Related Art In general, as a kind of machine tool, a solid-state laser device for focusing laser light with a lens and irradiating a workpiece and performing processing such as punching, cutting, welding, and soldering with high-density heat energy. In such a solid-state laser device, a discharge tube such as a flash lamp or an arc lamp is used as an excitation light source for generating a laser beam.

In recent years, in order to realize high-precision machining such as precision welding, a so-called waveform control function is added to drive and control the output of laser light in a pulsed manner to perform machining on a workpiece. Solid-state laser devices have also been developed. This waveform control function can be realized by adding a bank-type or inverter-type control circuit.

[0004]

However, in the case of the bank type control circuit, a plurality of capacitor banks are required, and in the inverter type control circuit, a transformer or the like is required. Therefore, either method is used. Even in this case, the power supply circuit becomes large and the device itself becomes expensive. Further, since the excitation light source is a discharge tube such as a flash lamp, it is difficult to control the light emission with a fine time width of several tens of microseconds or less due to its characteristics. Although there is a demand for realization of sub-waveform control, there is a problem that it is not possible to sufficiently cope with this.

The present invention has been made to solve the above-mentioned problems, and realizes fine, that is, high-speed pulse control to perform waveform control with higher precision and variety and is optimal. An object of the present invention is to provide a solid-state laser device capable of processing a workpiece under various processing conditions.

[0006]

In order to achieve the above-mentioned object, a solid-state laser device of the present invention irradiates the solid-state laser active medium with light from an excitation light source so that atoms in the solid-state laser active medium can be removed. In a solid-state laser device that excites to generate laser light, the excitation light source is formed of a plurality of semiconductor lasers, and an output control unit that controls the output of each semiconductor laser is provided.

The output control section may be formed so as to control the output of each semiconductor laser by controlling the magnitude and time width of the output pulse of each semiconductor laser.

Further, the output control section may be formed so as to drive and control one or a plurality of semiconductor lasers individually or simultaneously.

[0009]

According to the solid-state laser device of the present invention, a plurality of semiconductor lasers are used as a light source for exciting atoms in the solid-state laser active medium. By variably controlling the output of each semiconductor laser in a pulsed manner, the pulse control of the laser light used for processing can be performed at high speed.

[0010]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic view showing the overall structure of a YAG laser device which is an example of a solid-state laser device according to the present invention, FIG. 2 is an explanatory view showing the main parts thereof, and FIG. FIG. 4 is a graph showing an example of output states of a plurality of semiconductor lasers as pumping light sources in the example, and FIG. 4 shows laser light output from a YAG rod, which is one type of solid-state laser active medium, based on the state of FIG. It is a graph showing an output state.

As shown in FIG. 1, a YAG laser device 1
Is a YAG laser oscillator 3 on a desired oscillator base 2.
Is provided. This YAG laser oscillator 3 is provided with a YAG rod 6 as a solid-state laser active medium between a total reflection mirror 4 and an output mirror 5, and an atom in the YAG rod is driven by light from an excitation light source 8 driven by a power supply 7. The laser light L is emitted through the output mirror 5 after the excitation.

In this embodiment, this pump light source 8
Is not a conventional discharge tube, but an array of a plurality of semiconductor lasers, the drive of which is controlled by the CPU 9 and the output control unit 10 as will be described later, and the output from the YAG rod 6 is based on this. It is configured so that the pulsed laser light can be finely and rapidly controlled.

The laser beam L radiated through the output mirror 5 is partially or wholly reflected by a desired branching mirror 11 arranged on the right side of the output mirror 5, and is bent to the optical fiber entrance lens 13. . A branch shutter 12 that blocks the branched laser light is disposed between the branch mirror 11 and the optical fiber entrance lens 13. The laser light is condensed by the optical fiber incidence lens 13 at the laser output end 14 formed of an optical connector or the like to enable a plurality of branched outputs. Then, the laser light L focused on the laser output end 14 is passed through the optical fiber 15 to the desired work piece 18 from an appropriate emission unit 17 having two lenses 16 arranged at desired positions. It is supposed to be irradiated. Further, main safety shutters 19 are provided between the YAG rod 6 and the total reflection mirror 4 and the output mirror 5, respectively.

Next, the mechanism for generating the laser beam, which is the main part of this embodiment, will be further described with reference to FIG.

The embodiment shown in FIG. 2 is a side-excitation type, and Y as a solid-state laser active medium for generating a laser beam.
The excitation light source 8 for exciting the atoms in the AG rod 6 is
A plurality of (n) semiconductor lasers 20 are formed side by side on the side surface of the YAG rod 6.

The semiconductor lasers 20 and 20 are connected to a power source 7 for driving the semiconductor lasers 20 in a state where n laser diodes are connected in series. In addition, each semiconductor laser 2
An output control unit 10 for controlling the drive and output states thereof is connected to 0 and 20, and a desired drive signal for driving each semiconductor laser 20 is further supplied to the output control unit 10. The output CPU 9 is connected.

The output control unit 10 has a gate 21 to which a signal from the CPU 9 is input, a resistor 22 connected in series to the gate 21, and a transistor 23 whose base is connected to the resistor 22. It is composed of a control circuit, and this control circuit is provided corresponding to each semiconductor laser 20, 20.

Next, the operation of this embodiment having the above-mentioned structure will be described.

When the driving condition of the YAG laser device 1 is set and the driving is started, the CPU is operated according to the driving condition.
A drive signal for each semiconductor laser 20 is output from 9 to the output control unit 10. This drive signal determines what time width and with what intensity each semiconductor laser 20 emits light, and the semiconductor laser 20 pulses from LD1 to LDn sequentially based on this drive signal. Driven to emit light, resulting in an output state as shown in FIG. 3, for example.

When the semiconductor laser 20 emits light in this manner, the YAG rod 6 which uses this light as an excitation source generates laser light corresponding to the time width and intensity of this light. Let The output is from LD1 to LDn
When the output state of the semiconductor laser 20 up to this point is as shown in FIG. 3, the pulse width is as shown by the symbol T in FIG. The laser light is irradiated on the workpiece 18.

As described above, according to this embodiment, the YAG
Individual semiconductor laser 2 constituting the excitation light source 8 of the rod 6.
If the driving condition of 0 is changed and the time width and intensity thereof are changed variously, the output waveform of the laser beam output from the YAG rod 6 can be changed variously based on this, and thus the workpiece can be processed. Waveform control is performed according to the optimum conditions required when processing the object 18
Can be processed.

Further, since the semiconductor laser is capable of instantaneous pulse driving due to its characteristics, its emission time width is set to several 1
It can be finely controlled in units of 00 nsec. Therefore, the waveform of the laser beam output from the YAG rod 6 can be controlled much finer than that of a conventional discharge tube using an excitation light source, without using a complicated control circuit, and the workpiece 18 can be controlled. A wide variety of processing can be realized.

In this embodiment, the YAG rod 6 is used.
Although the description has been given by taking an example in which a plurality of semiconductor lasers are arrayed as the excitation light source, the excitation light source may be configured by using a semiconductor laser array in which a large number of semiconductor lasers are arrayed as each semiconductor laser. Needless to say.

FIG. 5 shows another embodiment of the mechanism for generating a laser beam by the end face pumping method. A semiconductor laser 20 is used as a pumping light source 8 for pumping atoms in a YAG rod 6 made of a solid laser crystal. 1 or a plurality of semiconductor laser arrays arranged in an array form on each end surface of the YAG rod 6 (two laser diodes LD1 on each end surface in this embodiment, a total of four laser diodes LD1,
LD2, LD3, LD4) are arranged so that the laser light is incident from the laser diodes LD1, LD2, LD3, LD4 in a direction inclined with respect to the optical axis of the YAG rod 6.

Each laser diode LD1, LD2, LD
The LDs 3 and 4 are connected to a power source (not shown) and are connected to the output control unit 10 for controlling the driving and output states thereof, as in the above embodiment. The output control unit 10 includes laser diodes LD1, LD2, L
A CPU 9 that outputs a desired drive signal for driving D3 and LD4 is connected.

The other structure is formed in the same manner as in the above embodiment.

Next, the operation of this embodiment having the above-mentioned structure will be described.

When the driving condition of the YAG laser device 1 is set and the driving is started, the CPU is operated according to this driving condition.
A drive signal for each semiconductor laser 20 is output from 9 to the output control unit 10. This drive signal determines what time width and with what intensity each semiconductor laser 20 emits light, and the semiconductor laser 20 pulses from LD1 to LD4 sequentially based on this drive signal. It is driven to emit light.

When the semiconductor laser 20 emits light in this manner, the YAG rod 6 which uses this light as an excitation source generates laser light corresponding to the time width and intensity of this light. Let

Since the present embodiment is of the end face excitation type, the laser diodes LD1, LD2, LD of the respective semiconductor lasers are used.
By adjusting the light emission time and the light emission intensity of the LD 4, the excitation laser output patterns as shown in FIGS. 6A to 6F can be obtained.

Here, each laser diode LD1, LD
2, pumping laser output of LD3, LD4 respectively
1, LP2, LP3, LP4. In the end face pumping method, when a plurality of laser diodes are arranged on each end face of the YAG rod 6, in order to make the spatial distribution of the pumping light uniform, it is preferable to make the outputs of all the laser diodes equal. For example, LP1 = LP2,
It is advisable to balance LP3 = LP4.

In FIGS. 6A and 6B, first, two laser diodes LD1 and LD2 are simultaneously driven, and immediately after that, the other two laser diodes LD3 and LD4 are simultaneously driven. , (A) is LP1 = LP2
<LP3 = LP4, (b) shows LP1 = LP2> LP
3 = LP4. First, two laser diodes LD1 and LD2 are shown in (c) and (d) of FIG.
Are simultaneously driven, and then two other laser diodes LD3 and LD4 are simultaneously driven after a lapse of a certain time. (C) is LP1 = LP2 <LP3 = LP4, and (d) is LP1 = LP2>. LP3 = LP4. (E) and (f) of the figure are those in which two laser diodes LD1 and LD2 are simultaneously driven, and the other two laser diodes LD3 and LD4 are simultaneously driven so as to overlap the driving time. Is.

As described above, according to this embodiment, various pump laser output patterns can be selected according to the driving conditions of the YAG laser device 1.

Further, since the pump laser output by the laser diode is constant without being attenuated during the driving time of the laser diode, comparison is made when the conventional capacitor bank and pump lamp whose output is attenuated are used. Then, the output control can be performed accurately.
It is also possible to use a light emitting device having an emission spectrum of the excitation wavelength instead of the semiconductor laser.

The solid-state laser device of the present invention can be used not only in industrial machines but also in other industrial fields such as medical machines and dental machines.

The present invention is not limited to the above embodiment, but various modifications can be made if necessary.

[0038]

As described above, according to the solid-state laser device of the present invention, since a plurality of semiconductor lasers are used as the excitation light source of the solid-state laser active medium, high-speed pulse control can be realized and higher It is possible to perform waveform control with high precision and variety, and therefore it is possible to cope with various processing conditions for the work piece and to perform processing on the work piece under optimum conditions.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of a solid-state laser device according to the present invention.

FIG. 2 is an explanatory view showing a main part of the solid-state laser device of the present invention shown in FIG.

FIG. 3 is a graph showing an example of output states of a plurality of semiconductor lasers as pumping light sources.

4 is a graph showing a waveform of laser light output from a solid rod based on an output state of the semiconductor laser array shown in FIG.

FIG. 5 is an explanatory view showing another embodiment of the main part of the solid-state laser device of the present invention.

6A to 6F are graphs showing the waveforms of laser light output from a solid rod based on the output state of the semiconductor laser array shown in FIG.

[Explanation of symbols]

 1 YAG laser device 3 YAG laser oscillator device 6 YAG rod 8 Excitation light source 9 CPU 10 Output control unit 20 Semiconductor laser 21 Gate 22 Resistor 23 Transistor

Claims (3)

[Claims] 1. A solid-state laser device for irradiating a solid-state laser active medium with light from the pumping light source to excite atoms in the solid-state laser active medium to generate laser light, wherein the pumping light sources are a plurality of semiconductor lasers. And a power controller for controlling the power of each semiconductor laser. 2. The output control section is formed so as to control the output of each semiconductor laser by controlling the magnitude and time width of the output pulse of each semiconductor laser. The solid-state laser device according to. 3. The solid state according to claim 1, wherein the output control unit controls so as to output one semiconductor laser independently or to output a plurality of semiconductor lasers at the same time. Laser device.