JPH0722676A - Pulse yag laser device - Google Patents

Abstract

PURPOSE:To enable continuous optimum processing by providing output feed back function so that specified laser output can be obtained. CONSTITUTION:A monitor circuit 12 which can detects output of laser light 11 is provided. A pulse voltage signal output from the monitor circuit 12 and a monitor voltage detecting a charge voltage of a capacitor are compared. The charge voltage of a capacitor is regulated in accordance with laser output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse YAG laser device which is excited by the light of a flash lamp or an arc lamp used in the industrial field.

[0002]

2. Description of the Related Art In recent years, solid-state YAG laser devices have been used as industrial machines in fields of semiconductors such as trimming and scribing, marking, soldering, welding and cutting, and their fields of use are expanding year by year.

A conventional pulse YAG laser device will be described below. FIG. 3 is a diagram showing a structure of a resonance part and a structure of a power supply part of a pulse YAG laser using a conventional flash lamp. In FIG. 3, 1 is a constant voltage DC power supply for charging the capacitor, 2 is a capacitor for supplying energy to the lamp, 3 is a switching element for limiting the lamp emission time, 4 is a reactance for discharging, and 13 is a capacitor 2. A charging voltage detection circuit for detecting the charging voltage of the power source, and a control circuit section 14 for controlling the power source section, which constitutes the power source section. 5 is a flash lamp connected to the condenser 2 through the switching element 3 and the discharging reactance 4, 6 is a laser medium,
Reference numeral 7 denotes a cavity having a reflection surface on its surface for allowing the light of the lamp 5 to efficiently enter the laser medium 6, 8 a partially transmissive mirror, and 9 a total reflection mirror, which constitute an optical resonator 10 of the resonance part. ing.

The operation of the pulse YAG laser device constructed as described above will be described below. The energy of the capacitor 2 charged to a constant voltage is supplied to the lamp 5 for a fixed time by the switching element 3. Due to the input energy to the lamp 5, the light emitted from the lamp for a certain period of time enters the laser medium 6 and is absorbed. The light that has passed without being absorbed is reflected by the reflecting surface and is incident on the laser medium 6 again. The energy of the absorbed light is oscillated by the optical resonator 10 surrounded by the partial transmission mirror 8 and the total reflection mirror 9, and a part of the energy becomes a laser beam 11 and is emitted to the outside.

[0005]

However, in the above-mentioned conventional configuration, the energy supplied to the lamp 5 is the charging energy of the condenser 2, and the emission energy of the lamp is absorbed by the rod of the laser medium 6 and the laser light is absorbed. Since the light is converted into the light 11, the conversion efficiency is affected by the state of the lamp 5, and the laser output varies.

In such a state, when performing laser processing using a pulsed YAG laser, the energy of the laser changes with the lapse of the lamp operating time, and the operating state and output state of the device are confirmed to set the conditions. Must be done, and if this condition is neglected, there will be too much energy,
There was a problem that energy became insufficient.

The present invention solves the above-mentioned conventional problems. A pulse YAG laser is used to set the capacitor charging voltage in accordance with the required laser output, resulting in excessive energy or insufficient energy during processing. It is an object of the present invention to provide a pulse YAG laser device capable of automatically adjusting its output without causing deterioration.

[0008]

In order to achieve this object, the pulse YAG laser of the present invention is provided with a monitor section for detecting laser output at a resonance section or a laser beam emitting end section at a processing point, and The strength is detected and output as an analog voltage, and the power supply unit compares it with the monitor voltage of the capacitor charging voltage detected in advance and controls the charging voltage of the capacitor.

[0009]

With this configuration, the energy supplied to the lamp can be controlled by the laser output by controlling the charging voltage to the condenser by the laser output, and processing using a constant pulse energy becomes possible.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a pulse YAG laser device according to an embodiment of the present invention. In FIG. 1, 1 to 11 and 13 have the same functions as conventional ones. That is, the energy of the capacitor 2 charged to a constant voltage is supplied to the lamp 5 by the switching element 3 for a fixed time. Due to the energy input to the lamp 5, the lamp light emission for a certain period of time enters the laser medium 6. The energy of the absorbed light is oscillated by the optical resonator 10 surrounded by the partial transmission mirror 8 and the total reflection mirror 9, and a part of the energy becomes a laser beam 11 and is emitted to the outside. At this time, the energy supplied to the lamp 5 is the condenser 2
The energy of the lamp 5 is converted into the energy of the laser light 11 with a constant conversion efficiency, which is determined by the charging voltage of However, the usage time of the lamp 5 or the optical resonator 10
The conversion efficiency may change depending on the state of the constituents that make up the above, and a predetermined laser beam may not be obtained.

In this embodiment, as shown in FIG. 1, the monitor circuit 12 detects a part of the laser beam 11 behind the total reflection mirror 9 or on the side transmitted through the partial transmission mirror 8. The monitor circuit 12 is composed of a sensor such as a pin photo sensor capable of converting an optical signal such as a laser beam into a voltage, and is internally provided so as to amplify a pulse voltage signal output from the sensor and hold a peak value. It has a voltage hold circuit. This output voltage is made to correspond to the reference laser output in advance, and the amplified pulse voltage signal is compared with the charging voltage of the capacitor 2 detected by the charging voltage detecting circuit 13 by the control circuit 14 to output the laser light. If the value is low, the control signal is fed back to the constant voltage DC power supply 1 so that the laser light output has a predetermined value, and the corresponding charging voltage of the capacitor 2 is obtained.

The charging voltage of the capacitor 2 can be adjusted by phase control using a thyristor or the like which has been conventionally used. By adjusting the charging voltage in this way, the laser light can be adjusted. This monitor circuit 1
When detecting the laser light transmitted from the partial transmission mirror 8, a laser light attenuation mechanism 2 is used for monitoring.

FIG. 2 shows a pulse Y according to another embodiment of the present invention.
It is a block diagram which shows an AG laser device. In FIG. 2, the laser light 11 emitted through the partial transmission mirror 8 is guided from the processing optical system 15 to the processing emission end unit 17 via the optical fiber 16 and is irradiated to the processing target 18. Here, the monitor circuit 12 detects the laser light 11 in the processing emission end unit 17.

In general, laser light is guided to a processing point through some optical systems, so that there is some attenuation.
Therefore, when the laser beam at the processing point is detected, the intensity of the laser beam necessary for actual processing can be detected. Further, if there is some trouble in the optical system and the actual laser light at the processing point is detected even when the output is reduced, it is possible to take some measures.
Therefore, as shown in FIG. 2, the monitor circuit 12 is provided at the emission end of the laser light.

In this way, the laser output required for processing is monitored at the processing emission end, the voltage converted value is compared with the value monitored for the capacitor charging voltage, and the capacitor charging voltage is changed to obtain the laser. The intensity of light can be adjusted.

[0016]

As described above, according to the present invention, a part of the laser light is received by the light receiving sensor, the amplified pulse voltage signal is held as a monitor signal, and the hold voltage and the charging voltage of the capacitor are detected. By comparing the monitored voltage and adjusting the capacitor charging voltage so that a predetermined laser output can be obtained, the laser light required for processing can be automatically adjusted, and a high-quality pulsed YAG laser can be obtained. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of a pulse YAG laser device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a pulse YAG laser device according to another embodiment of the present invention.

FIG. 3 is a block diagram of a conventional pulse YAG laser device.

[Explanation of symbols]

 1 constant voltage DC power supply 2 capacitor 3 switching element 4 discharge reactance 5 lamp 6 laser medium 7 cavity 8 partial transmission mirror 9 total reflection mirror 10 optical resonator 11 laser light 12 monitor circuit 13 charging voltage detection circuit 14 control circuit 15 for processing Optical system 16 Optical fiber 17 Processing exit end unit 18 Object to be processed

Claims (3)

[Claims] 1. A pulsed YAG laser device in which energy of a capacitor charged to a constant voltage is supplied to a lamp for a certain period of time, and lamp light emission for a certain period of time is incident on a laser medium to emit laser light. The light receiving sensor of the part receives the amplified pulse voltage signal as a monitor signal and a monitor circuit that compares the hold voltage with the monitor voltage that detects the charging voltage of the capacitor. And a control circuit that adjusts the charging voltage so that the pulse YAG laser device. 2. The pulse YAG laser device according to claim 1, wherein the monitor circuit is provided behind a total reflection mirror for emitting laser light or outside a partial transmission mirror. 3. The pulse YAG laser device according to claim 1, wherein the monitor circuit is provided at a laser beam emitting end of the processing point.