JPH04133466U - Ultrasonic Q switch laser device - Google Patents

Abstract

(57) [Summary] [Purpose] An ultrasonic Q-switch that does not waste time due to peak output pulse control, can operate at high speed, and does not damage the workpiece. Provides laser equipment. [Structure] For a while after the control signal 24 (FIG. 2(a)) is applied, the control signal (FIG. 2(b)) output from the control circuit 23 causes the second Q-switch modulator 16 to
The high frequency power of 0 MHz remains applied. Therefore, the diffraction loss in the first Q-switch modulator 15 disappears, but the diffraction loss in the second Q-switch modulator 16 remains. As a result, the Q-switched pulsed light oscillates with resonator loss, so sufficient gain cannot be obtained and the first peak pulse is suppressed, resulting in a Q-switched waveform ( 2) is obtained.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is an ultrasonic Q-switch that generates pulsed laser light using an ultrasonic Q-switch. Regarding pulse laser equipment, in particular, it is necessary to electrically control the peak output of pulsed laser light from the outside. The present invention relates to an ultrasonic Q-switched laser device.

0002

[Conventional technology]

Conventionally, solid-state lasers using ultrasonic Q-switch modulators have extremely high peak output values. It is known to output high pulses, and is used in marking devices, trimming devices, etc. It is applied in many fields.

0003 By the way, this ultrasonic Q-switched laser can be applied to marking equipment, for example. If the repetition frequency of the Q-switch pulse exceeds 2kHz, The peak value of the first Q-switch pulse that turns the laser light from off to on is extremely high. It gets bigger and bigger. Therefore, a deep and large machining trajectory is created only at the location corresponding to this pulse. Otherwise, the workpiece may be damaged or the substrate may be damaged. There are cases.

0004 Conventionally, the method of controlling this peak pulse involves using a mechanical system outside the laser cavity. After installing a shutter mechanism and oscillating a Q-switch pulse, the shutter mechanism is opened and the sharp How to process by deleting the high part of the head pulse and oscillating the Q switch pulse The power supplied to the Q-switch modulator is reduced just before the inversion occurs, causing a weak continuous oscillation. Q-switch pulse oscillation is performed after reducing the distribution amount, and this produces a peak pulse. There are ways to keep it low.

[0005]

[Problem that the idea aims to solve]

However, the peak output control method for conventional Q-switched lasers requires the following: There was a problem like this. First, in the method using a mechanical shutter mechanism, the shutter mechanical delays resulting in wasted time and rapid repetition. It was difficult to operate at high speed. It also reduces the power supplied to the Q-switch modulator. In this method, in order to reduce the amount of population inversion just before the Q-switch pulse oscillation, a weak Since continuous oscillation is performed, there is wasted time and high-speed operation is difficult. There were problems such as damage to property.

[0006] The present invention was developed in view of the above problems, and its purpose is to There is no wasted time for control, high-speed operation is possible, and To provide an ultrasonic Q-switched laser device that does not damage a workpiece. It is in.

[0007]

[Means to solve the problem]

The ultrasonic Q-switched laser device of the present invention uses a laser beam generator that generates laser beams. Then, the laser beam generated by this laser beam generating means is modulated by ultrasonic waves to generate a laser beam. a pair of Q-switch modulators that generate a high frequency signal generating section that supplies a high frequency modulation signal for generating waves; The timing of the high-frequency modulation signal supplied to the Q-switch modulator is controlled, and the Q-switch Suppress the first peak pulse of pulsed laser light using a switch modulator The control means controls the first peak pulse of the pulsed laser beam. electrically suppressed.

[0008]

【Example】

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

[0009] Figure 1 shows the configuration of an ultrasonic Q-switched laser device according to an embodiment of the present invention. It is.

0010 This ultrasonic Q-switched laser device includes a laser resonator 10 and this laser resonator. It is composed of a high frequency signal generator 17 that supplies a high frequency modulation signal to the device 10. Ru. The laser resonator 10 includes a solid-state laser material 11 between a reflecting mirror 13 and a reflecting mirror 14. , a first Q-switch modulator 16, and a second Q-switch modulator 17 are arranged in sequence. and excitation light for exciting the solid-state laser material 11 in the vicinity of the solid-state laser material 11. It is configured by arranging a source 12 and outputs laser pulses toward the left side of the figure. ing. The solid-state laser material 11 is excited by the excitation light source 12, thereby generating The laser light is transmitted to the first Q-switch modulator 16 and the second Q-switch modulator 17. It is designed to be modulated internally. The first Q-switch modulator 15 and and the second Q-switch modulator 16 receive modulation signals from the high-frequency signal generator 17, respectively. A high frequency signal is applied, which generates an ultrasonic wave, and this ultrasonic wave The laser beam output from the body laser substance 11 is modulated and pulsed.

[0011] The high frequency signal generator 17 includes an oscillator 18 that emits at 40 MHz, for example, and a Q switch. a first modulation circuit 19 that outputs a high frequency modulation signal for modulating the pulse train; Each output of the second modulation circuit 20, the first modulation circuit 19, and the second modulation circuit 20 is set to a predetermined value. The first power amplifier 21, the second power amplifier 22, and the control to amplify the level of It is constituted by a circuit 23 and is controlled by a control signal 24 from a control section (not shown). It has become so. This control signal 24 is used when a Q-switch pulse is required. It is a pulse that turns on and off at a certain repetition frequency.

0012 The control signal 24 is applied to the first modulation circuit 19, the second modulation circuit 20, and the control circuit 23. are input respectively. The control circuit 23 receives the control signal 24 and turns on after a certain time T. Outputs a control signal that turns on (high level). The output signal of this control circuit 23 is 2 modulation circuit 20. The first modulation circuit 19 and the second modulation circuit 20 are Furthermore, a high frequency signal output from an oscillator 18 is supplied. The first modulation circuit 19 , modulates the high frequency signal output from the oscillator 18 using the control signal 24. on the other hand , the second modulation circuit 20 is configured so that the control signal output from the control circuit 23 is off (low level). (bell), the high frequency signal of the oscillator 18 is output as is, and its control signal is turned on. After that, similarly to the first modulation circuit 19, the oscillator 18 outputs the signal using the control signal 24. modulates high-frequency signals. High frequency modulation signal modulated by first modulation circuit 19 is the high frequency modulation signal output from the first power amplifier 21 and the second modulation circuit 20 are each amplified to a predetermined level in the second power amplifier 22, and then The first Q-switch modulator 15 and the second Q-switch modulator 16 of the resonator 10 are supplied respectively.

[0013] Next, the operation of the Q-switched laser device of this example will be explained with reference to FIG. do. Figure 2 shows the signal waveforms and Q-switch pulse waveforms of each part of this device. It is expressed graphically, with time on the horizontal axis and signal strength on the vertical axis.

[0014] The waveform of the control signal 24 is as shown in (a) of FIG. At times, the control signal 24 is turned on and off at a certain repetition frequency, and the control circuit 23, The signals are input to the first modulation circuit 19 and the second modulation circuit 20, respectively. Control circuit 23 receives this control signal 24, and after a certain period of time T has elapsed, as shown in FIG. A control signal having a waveform that is at the high level is output to the second modulation circuit 20. First modulation circuit 1 9 modulates the high frequency signal output from the oscillator 18 using the control signal 24, and A signal as shown in 2(c) is output. On the other hand, the second modulation circuit 20 After time T has elapsed, a modulated signal as shown in FIG. 2(d) is output. These modulation signals are are input to the first power amplifier 21 and the second power amplifier 22, respectively, and set to a predetermined level. is amplified. Based on the outputs of these first power amplifier 21 and second power amplifier 22, The first Q-switch modulator 15 and the second Q-switch modulator 16 generate ultrasonic waves. A wave is generated, which modulates the frequency of the laser light generated from the solid-state laser material 11. will be held. FIG. 2(f) shows the Q-switch waveform (2).

[0015] Here, the Q switch waveform (1) shown in FIG. 2(e) is the output of the control circuit 23. A more uncontrolled conventional waveform, with a high peak pulse oscillation only on the first shot. It becomes. This occurs during T when the control signal 24 (Fig. 2(a)) is at low level. Laser oscillation is suppressed and energy is accumulated until the population inversion is completely saturated. It is et al. In contrast, in this embodiment, the period T after the control signal 24 is applied is , the second Q switch is activated by the control signal ((b) in FIG. 2) output from the control circuit 23. The high frequency power of 40 MHz remains applied to the channel modulator 16. Therefore, the first The diffraction loss in the second Q-switch modulator 15 is eliminated, but the second Q-switch modulator 1 The diffraction loss within 6 remains, and as a result, the switch pulse light has a resonator loss. Oscillates in certain conditions. Therefore, sufficient gain cannot be obtained and the first peak pulse Therefore, a Q-switched waveform (2) as shown in Fig. 2(f) is obtained. .

[0016] In this way, in the ultrasonic Q-switched laser device of this embodiment, the laser resonator 10 Since the first peak pulse of the Q switch pulse can be suppressed electrically from the outside, the There is no wasted time unlike the conventional mechanical shutter mechanism method. High-speed operations with rapid repetition are possible. Also, the supply to conventional Q-switch modulators As with the method of reducing power, it is necessary to perform continuous oscillation immediately before Q-switch pulse oscillation. Since there is no need for this, there is no damage to the workpiece.

[0017]

[Effect of the idea]

As explained above, according to the present invention, laser light is modulated by ultrasonic waves to generate pulses. A pair of Q-switch modulators that convert into an ultrasonic wave generator having a high frequency signal generator that supplies a modulated high frequency signal for generating In a sonic Q-switched laser device, the high frequency that is supplied to one Q-switched modulator Since the timing of the modulation signal is controlled, the pulse is controlled by the Q-switch modulator. It is possible to suppress the first peak pulse of the converted laser beam, and it is possible to suppress the first peak pulse of the High-speed operation can be achieved without wasting time and preventing damage to the workpiece. There will be no need to give.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a Q-switched laser device according to an embodiment of the present invention.

2 is a diagram schematically representing signal waveforms and Q-switch pulse waveforms of each part of the Q-switched laser device in FIG. 1. FIG.

[Explanation of symbols]

10 Laser resonator 11 Solid state laser material 12 Excitation light source 13, 14 Reflector 15 First Q-switch modulator 16 Second Q-switch modulator 17 High frequency signal generation section 18 Oscillator 19 First modulation circuit 20 Second modulation circuit 21 1st power amplifier 22 Second power amplifier 23 Control circuit 24 Control signal

Claims (1)

[Scope of utility model registration request] 1. A laser beam generating means for generating a laser beam, a pair of Q-switch modulators for modulating the laser beam generated by the laser beam generating means with an ultrasonic wave to pulse it, and each of these Q-switch modulators. a high-frequency signal generation section that supplies a high-frequency modulation signal for generating ultrasonic waves to the Q-switch modulator; An ultrasonic Q characterized by comprising a control means for suppressing the first peak pulse of light.
Switch laser equipment.