CN111922509B

CN111922509B - Q-switched laser scanning processing device and signal control method thereof

Info

Publication number: CN111922509B
Application number: CN202010787170.4A
Authority: CN
Inventors: 刘海
Original assignee: Langfang Yuantuo Technology Co ltd
Current assignee: Langfang Yuantuo Technology Co ltd
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2022-03-15
Anticipated expiration: 2040-08-10
Also published as: CN111922509A

Abstract

The invention relates to a Q-switched laser scanning processing device and a signal control method thereof, and the Q-switched laser scanning processing device comprises a laser, a scanning system and a signal control system, wherein the laser comprises a full-reflection cavity mirror, a laser pumping module, a Q switch and an output cavity mirror and outputs laser pulses; the scanning system comprises a reflector and a galvanometer motor, wherein the galvanometer motor drives the reflector to swing in a reciprocating manner, and the laser pulses irradiated on the reflector are scanned into linear beams; the signal control system comprises a TTL signal generator, a sawtooth wave signal generator, a swinging signal generator and a frequency synthesizer. The invention can change the laser pulse power value in the reflector lens only by adjusting the signal generator, can realize the uniform processing of the object surface, and has simpler and safer operation.

Description

Q-switched laser scanning processing device and signal control method thereof

Technical Field

The invention relates to a Q-switched laser scanning processing device and a signal control method thereof, in particular to a processing device for uniformly scanning and processing the surface of an object by adopting a pulse laser based on a Q-switched technology and a signal control method thereof.

Background

The method for processing the surface of the object by adopting laser comprises the following steps: pollutant cleaning, microstructure preparation, surface strengthening and the like. In order to realize the two-dimensional coverage of the laser spot for processing on the surface of an object, a translation motion mode combining one-dimensional galvanometer scanning and a translation stage is generally adopted.

The one-dimensional galvanometer motor is driven by periodic waveforms such as sine waves or triangular waves and the like to drive the one-dimensional galvanometer to swing in a reciprocating mode, light beams output by the laser irradiate onto the reflecting mirror at an angle of 45 degrees, and therefore the laser light beams are scanned in a one-dimensional straight line in a reciprocating mode by the reflecting mirror which swings in a reciprocating mode. The subsequent one-dimensional straight line is combined with the one-dimensional translation of the translation stage or the galvanometer to realize the processing of the laser spots on the surface of the object. The laser generally adopts a pulse laser adopting a Q-switching technology, and the Q switch can repeatedly accumulate and release energy of laser in a laser resonant cavity, so that the pulse laser with large energy is output.

However, when the periodic waveform is used to drive the galvanometer motor, the direction of the galvanometer mirror needs to be changed at the position of the wave crest or the wave trough of the periodic waveform, so that a period of time with very low or zero swing speed exists at the edge of the swing position of the reflective mirror, and the laser still keeps constant value output of laser pulse at the moment, which causes more laser energy to stay at the edge of a one-dimensional straight line and causes uneven processing.

Disclosure of Invention

The invention aims to solve the technical problem of uneven scanning processing edge, and provides a processing device for uniformly processing the surface of an object by a pulse laser based on a Q-switching technology and a signal control method thereof.

The invention can be realized by the following technical scheme: a Q-switched laser scanning processing device comprises a laser, a scanning system and a signal control system, wherein the laser comprises a full-reflection cavity mirror, a laser pumping module, a Q switch and an output cavity mirror and outputs laser pulses; the scanning system comprises a reflector and a galvanometer motor, the galvanometer motor drives the reflector to swing in a reciprocating mode, the laser pulses irradiated to the reflector are scanned into linear beams, and the linear beams are matched with a one-dimensional translation table to carry out surface machining on a workpiece; the signal control system comprises a TTL signal generator, a sawtooth wave signal generator, a swing signal generator and a frequency synthesizer, wherein the TTL signal generator outputs a TTL signal with a duty ratio of 50% and a frequency of 1kHz-100kHz square wave, and the sawtooth wave signal generator outputs a signal with a duty ratio of t₁The TTL signal and the sawtooth wave signal are synthesized by the frequency synthesizer, a Q switch control signal is output to control the on-off of the Q switch, and the TTL signal and the sawtooth wave signal are triggered at the moment to output sawtooth wave signals, and at t₁~ t₂The peak power of the output laser pulse is reduced; the swing signal generator outputs a swing signal of a periodic wave, the swing signal is input to the galvanometer motor to control the reciprocating swing of the reflecting mirror, wherein t is₁Is a certain time around the peak of the wobble signal, t₂Is a certain time after a duration Δ t.

Furthermore, the signal control system further comprises a trigger signal generator and a signal synchronizer/delayer, wherein the trigger signal generator outputs a square-wave trigger signal, and the trigger signal is at t₁~ t₂Internally outputting a high level, and outputting a low level in the rest time periods; the signal synchronizer/delayer is simultaneously connected with the trigger signal generatorAnd said wobble signal generator, correlate the signal outputs of both; at said t₁At the moment, the trigger signal is output, the sawtooth wave signal is triggered and output, after the sawtooth wave signal and the TTL signal are operated and synthesized, a square wave signal with a rising edge changing into an inclination is output to serve as the Q switch control signal, and the laser is controlled at t₁~ t₂And internally outputting low-peak-power laser pulses with reduced peak power, wherein in the rest time periods, the TTL signals are the Q switch control signals, and the laser pulses with normal peak power are output.

Further, the wobble signal is a triangular wave, a sine wave, or a cosine wave. The Q-switch is an electro-optic Q-switch or an acousto-optic Q-switch.

Further, the number of the laser pulses whose output peak power is reduced within Δ t is one or more than two.

The invention also comprises the following technical scheme: a signal control method for Q-switched laser scanning processing device is characterized in that a signal synchronizer/delayer is associated with a swing signal generator and a trigger signal generator, and t near the peak value of the swing signal is observed and modulated₁At the moment, the high level of the trigger signal is output, the sawtooth wave signal is triggered and output at the moment, the on-off of a Q switch is controlled after the sawtooth wave signal and the TTL signal are synthesized through operation, and at t₁~ t₂And forming a square wave signal with a rising edge becoming inclined, outputting a laser pulse with reduced peak power by the laser, outputting a low level of the trigger signal in other time periods, not triggering and outputting the sawtooth wave signal at the time, controlling the on-off of the Q switch by the TTL signal, and outputting a laser pulse with normal peak power by the laser.

Compared with the prior art, the invention has the following advantages:

(1) the power value of laser pulse irradiated on the reflector lens is changed by adjusting the signal generator, so that uniform processing of the surface of an object is realized, the laser does not need to be stopped during adjustment, continuous working can be realized, and continuous scanning can be realized by once adjustment.

(2) The form of the laser pulse output by the laser is associated with the swing signal of the galvanometer motor, the automatic association is realized by utilizing a signal synchronizer/time delay, and the stable scanning processing can be realized only by adjusting during the initial use.

(3) The device adopts a common signal generator, a pulse laser and a scanning system, does not need to specially process parts, can be built on the basis of the laser of the existing scanning processing, and has low cost and simple and convenient operation.

(4) The signal adjusting method is simple, has low requirements on operators, and improves the scanning processing efficiency and the application range.

Drawings

To further illustrate the details of the present invention, the following detailed description is provided in conjunction with the examples and the accompanying drawings, in which:

FIG. 1 is a schematic structural composition diagram of the present application

FIG. 2A schematic diagram of the synthesis of Q-switch control signals

FIG. 3 is a waveform diagram of Q switch control signal and a laser pulse waveform diagram

Description of reference numerals: 1. laser pulse, 2, TTL signal, 3, swing signal, 4, sawtooth wave signal, 5, trigger signal, 11, low peak power laser pulse, 21, Q switch control signal, 60, holophote, 61, laser pumping module, 62, Q switch, 63, output cavity mirror, 70, TTL signal generator, 71, sawtooth wave signal generator, 72, trigger signal generator, 73, signal synchronizer/delayer, 74, swing signal generator, 75, frequency synthesizer, 80, reflection lens, 81, vibrating mirror motor, 82, beam formed by laser pulse, 83, straight beam.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Referring to fig. 1-3, the present invention provides a Q-switched laser scanning processing apparatus, which includes a laser, a scanning system and a signal control system, wherein the laser includes a total reflection cavity mirror 60, a laser pumping module 61, a Q-switch 62 and an output cavity mirror 63, and outputs a laser pulse 1; the scanning system comprises a reflector 80 and a galvanometer motor 81, wherein the galvanometer motor 81 drives the reflector 80 to reciprocate, laser pulses irradiated on the reflector 80 are scanned into linear beams 83, and the linear beams are matched with one dimensionThe translation table is used for processing the surface of the workpiece; the signal control system comprises a TTL signal generator 70, a sawtooth wave signal generator 71, a swinging signal generator 74 and a frequency synthesizer 75, wherein the TTL signal generator 70 outputs a TTL signal 2 with a 50% duty ratio and a square wave with the frequency of 1kHz-100kHz, and the sawtooth wave signal generator outputs a square wave with the duty ratio of t₁Triggered at the moment to output a sawtooth wave signal 4, after the TTL signal 2 and the sawtooth wave signal 4 are synthesized by a frequency synthesizer 75, a Q switch control signal 21 is output to control the on-off of a Q switch 62, and at t₁~ t₂The peak power of the output laser pulse is reduced; the wobble signal generator 74 outputs a wobble signal 3 of a periodic wave, and inputs the wobble signal to the galvanometer motor 81 to control the reciprocal oscillation of the mirror plate 80, where t₁Is a certain time around the peak of the wobble signal 3, t₂Is a certain time after a duration Δ t.

Furthermore, the present invention further comprises a trigger signal generator 72 and a signal synchronizer/delayer 73, wherein the trigger signal generator 72 outputs a trigger signal 5 as a square wave, and the trigger signal 5 is at t₁~ t₂Internally outputting a high level, and outputting a low level in the rest time periods; the signal synchronizer/delayer 73 is connected with the trigger signal generator 72 and the wobble signal generator 74 at the same time, and correlates the signal outputs of the two; at t₁At the moment, a trigger signal 5 is output, a sawtooth wave signal 4 is triggered and output, after the sawtooth wave signal 4 is operated and synthesized with a TTL signal, a square wave signal with a rising edge changing into an inclination is output to serve as a Q switch control signal, and a laser is controlled to be at t₁~ t₂The low peak power laser pulse 11 with reduced internal output peak power reduces the processing force of the beam 82 on the surface of the object, at this time, the swing speed of the mirror 80 is very low or zero, however, the processing force also becomes low, so that the problem of processing the edge by laser scanning is avoided. The specific reason is as follows: the slow rising edge of the Q-switch control signal 21 causes the laser energy to be released slowly, so that the transient avalanche output phenomenon of the laser energy does not occur, thereby reducing the peak power of the output laser.

The signal control method for the Q-switching laser scanning processing device comprises the following steps: wherein a signal synchronizer/delayer 73 associates a wobble signal generator 74 with a trigger signal generator 72, byObserving and modulating, outputting the high level of a trigger signal 5 at the time t1 near the peak value of a wobble signal 3, triggering and outputting a sawtooth wave signal 4 at the time, controlling the on-off of a Q switch after the sawtooth wave signal 4 and a TTL signal 2 are calculated and synthesized, and controlling the on-off of the Q switch at the time t₁~ t₂And a square wave signal with a rising edge changing to be inclined is formed, the laser outputs laser pulse with reduced peak power at the moment, the low level of the trigger signal 5 is output in other time periods, the sawtooth wave signal is not triggered and output at the moment, the TTL signal controls the on-off of the Q switch, and the laser outputs laser pulse with normal peak power.

At t₁~ t₂The number of laser pulses 11 having a low peak power present in the internal period depends on the frequency of the laser pulses output from the Q-switch 62, and may be 1 or more.

The Q switch can be an electro-optic Q switch, an acousto-optic Q switch or other Q-switching components, and the laser can be a side-pump laser based on acousto-optic Q-switching and can also be an end-pumped laser based on electro-optic Q-switching. The laser can be an electro-optical Q-switching component or other Q-switching components, and can also be an end-pump laser or other types of laser cavity types. The sawtooth wave signal 4 can be replaced by other waveforms which can relieve the output peak power of the pulse laser. The TTL signal generator 70 can also output square wave signals with other duty cycles and frequencies, and both the duty cycle and the frequency can be adjusted.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. The utility model provides a transfer Q laser scanning processingequipment, includes laser instrument, scanning system and signal control system, its characterized in that: the laser comprises a full-reflection cavity mirror (60), a laser pumping module (61), a Q switch (62) and an output cavity mirror (63), and outputs laser pulses (1); the scanning system comprises a reflecting mirror (80) and a galvanometer motor (81), wherein the galvanometer motor (81) drives the reflecting mirror (80) to swing in a reciprocating manner to irradiateThe laser pulse emitted to the reflecting mirror (80) is scanned into a linear beam (83), and the surface of a workpiece is processed by matching with a one-dimensional translation table; the signal control system comprises a TTL signal generator (70), a sawtooth wave signal generator (71), a swing signal generator (74) and a frequency synthesizer (75), wherein the TTL signal generator (70) outputs a TTL signal (2) with a duty ratio of 50% and a frequency of 1kHz-100kHz square wave, and the sawtooth wave signal generator outputs a signal at t₁The moment is triggered to output a sawtooth wave signal (4), the TTL signal (2) and the sawtooth wave signal (4) are synthesized by the frequency synthesizer (75) and then output a Q switch control signal (21) to control the on-off of the Q switch (62), and at t₁～t₂The peak power of the output laser pulse is reduced; the swing signal generator (74) outputs a periodic wave swing signal (3) which is input to the galvanometer motor (81) to control the reciprocating swing of the reflecting mirror (80), wherein t is₁Is a certain time, t, around the peak of the wobble signal (3)₂Is a certain time after a period of time Δ t; the signal control system also comprises a trigger signal generator (72) and a signal synchronizer/delayer (73), wherein the trigger signal generator (72) outputs a trigger signal (5) which is a square wave, and the trigger signal (5) is at the t₁～t₂Internally outputting a high level, and outputting a low level in the rest time periods; the signal synchronizer/delayer (73) is simultaneously connected with the trigger signal generator (72) and the wobble signal generator (74) and correlates the signal outputs of the trigger signal generator and the wobble signal generator; at said t₁At the moment, the trigger signal (5) is output, the sawtooth wave signal (4) is triggered and output, after the sawtooth wave signal and the TTL signal are operated and synthesized, a square wave signal with a rising edge changing into an inclination is output to serve as the Q switch control signal, and the laser is controlled to be at t₁～t₂And internally outputting a low-peak-power laser pulse (11) with reduced peak power, wherein in the rest time periods, the TTL signal (2) is the Q switch control signal and controls the laser to output a laser pulse (1) with normal peak power.

2. The Q-switched laser scanning machining device according to claim 1, wherein the wobble signal (3) is a triangular wave, a sine wave or a cosine wave.

3. The Q-switched laser scanning machining apparatus according to claim 1, wherein the Q-switch is an electro-optical Q-switch or an acousto-optical Q-switch.

4. The Q-switched laser scanning machining apparatus according to claim 1, wherein the number of the laser pulses whose output peak power is reduced within Δ t is one or two or more.

5. The Q-switched laser scanning machining device according to claim 1, wherein the duty cycle and the frequency of the square wave output by the TTL signal generator (70) are both adjustable.

6. A signal control method based on the Q-switched laser scanning processing apparatus according to any one of claims 1 to 5, characterized in that: said signal synchronizer/delayer (73) associates said wobble signal generator (74) with said trigger signal generator (72), observing, modulating, said t around the peak of said wobble signal (3)₁At the moment, the high level of the trigger signal (5) is output, the sawtooth wave signal (4) is triggered and output at the moment, the sawtooth wave signal (4) and the TTL signal (2) are operated and synthesized, the on-off of a Q switch is controlled, and at t₁～t₂And forming a square wave signal with a rising edge changing into an inclined state, outputting a laser pulse with reduced peak power by the laser, outputting a low level of the trigger signal (5) in other time periods, not triggering and outputting the sawtooth wave signal at the time, controlling the on-off of the Q switch by the TTL signal, and outputting a laser pulse with normal peak power by the laser.