CN110943368A - Device, system and method for reliable control of semiconductor laser output power - Google Patents

Abstract

Translated fromChinese

本发明公开了一种可靠控制半导体激光器输出功率装置，系统及方法。它包括紧急停止开关，它还包括：两个处理器，分别用于接收紧急停止开关控制信号，激光功率信号以及状态信号；功率信号控制单元，用于接收两个处理器的功率信号，比较功率信号，控制功率输出信号；逻辑运算单元，用于分别接收两个处理器状态信号，比较状态信号，控制状态输出信号；多路选择器，用于接收控制状态输出信号，选择电流信号的通路。本发明采用两个处理器以及逻辑运算单元对软件及硬件状态进行检测比较，在软件失效或硬件故障都能有效避免错误的激光功率输出，与传统方案相比既可以使用软件控制激光输出功率又能满足安全规范要求。

The invention discloses a device, system and method for reliably controlling the output power of a semiconductor laser. It includes an emergency stop switch, and it also includes: two processors, respectively used to receive the emergency stop switch control signal, laser power signal and status signal; a power signal control unit, used to receive the power signals of the two processors, compare the power signal, control power output signal; logic operation unit, used to receive two processor state signals respectively, compare state signals, control state output signal; multiplexer, used to receive control state output signal, select the path of current signal. The present invention uses two processors and a logic operation unit to detect and compare the state of software and hardware, and can effectively avoid wrong laser power output in case of software failure or hardware failure. Can meet the requirements of safety regulations.

Description

Apparatus, system and method for reliably controlling output power of semiconductor laser

Technical Field

The invention belongs to a laser power control technology, and particularly relates to a control technology when the laser emission needs to be stopped emergently.

Background

In laser medical application, safety application laser is taken as a product mandatory standard, for example, in GB9706, it is clearly required that a medical laser product must have an emergency stop laser emission switch capable of terminating laser emission in an emergency, a timed stop laser emission function has two independent time control devices, the emergency stop laser emission switch must be controlled by hardware and cannot use a pure software function, and the like. In the conventional laser power control method, as shown in fig. 1, arelay 1 directly controlled by an emergency stop switch 5 is added before a laserdriving power supply 2, and when the emergency stop switch 5 is turned off, thelaser relay 1 cuts off the power supply of the laserdriving power supply 2 to achieve the purpose of stopping laser emission. However, this solution needs to shut down the power supply of the laser driving power supply, and there are other additional monitoring functions in the laser driving power supply which also cause this part of functions to fail to work when the power supply is stopped, and the laser driving power supply needs to be powered on again when the emergency fault is resolved, and for most of the lasers, it needs to wait for a long time to undergo processes such as soft start, self-checking, and preheating. The adjustable potentiometer 4 is often used for adjusting the laser power to control the output of the laserdriving power supply 2 to achieve the purpose of adjusting the laser power, but the method cannot adjust the laser power through software and cannot meet the requirements in terms of functions and user experience.

In order to avoid the disadvantages of inconvenient use and incapability of controlling laser power by software caused by suddenly turning off the laser power supply, as shown in fig. 2, a conventional method for controlling laser power is added with a digital-to-analog converter 203 and aprocessor 205, and then theprocessor 205 periodically reads a signal of an emergency stop switch 204, and when the emergency stop switch 204 is turned off, theprocessor 205 controls the digital-to-analog converter 203 to reduce an analog output to zero; at this time, the laserdriving power supply 201 reduces the driving current of thelaser 202 under the action of the analog control signal, so as to achieve the purpose of stopping laser emission. The scheme has the advantages that the output power of the laser can be controlled through software, and the power supply of the whole power supply does not need to be turned off when the laser is stopped emergently. However, the solution cannot meet the national mandatory safety standards in the application occasions requiring high requirements on reliability and safety, and the laser power control will be disabled when theprocessor 205 has software defects or is reset and crashed due to interference.

CN 103384949B discloses "forbidding unauthorized access to laser source"; the security unit comprises a detector for detecting unauthorized access to the laser source and is adapted to cause the laser source to be permanently disabled upon unauthorized access to the laser source. The essence of the method is that when the laser is used in an unauthorized way, the laser source is irreversibly stopped. Is not suitable for the above occasions.

Disclosure of Invention

The invention aims to solve the problem that laser power control fails due to software failure when the existing software-based control is in emergency stop, and provides a device, a system and a method for reliably controlling the output power of a semiconductor laser.

The invention has a plurality of technical schemes: one of them is: the reliable control semiconductor laser output power device, it includes the emergency stop switch, it also includes:

at least two processors respectively used for receiving the emergency stop switch control signal, the laser power signal and the status signal;

the power signal control unit is used for receiving power signals of at least two processors, comparing the power signals and controlling power output signals;

the logic operation unit is used for respectively receiving at least two processor state signals, comparing the state signals and controlling state output signals;

and the multiplexer is used for receiving the control state output signal and selecting a path of the current signal.

The invention adopts at least two processors and a logic operation unit to compare the software and hardware states, can effectively avoid wrong laser power output when software fails or hardware fails, and can use software to control the laser output power and meet the requirement of safety specification compared with the traditional scheme.

The further optimized technical scheme is as follows: the power signal control unit includes:

a comparator: the laser power signal processing device is used for receiving the laser power signals of the two processors, judging the two power signals and outputting the power signals;

and the digital-to-analog converter is used for converting the received output power digital signal into an analog signal and outputting the analog signal.

The device has high corresponding speed and high control efficiency by digital data comparison and output of analog power signals.

The further optimized technical scheme is as follows: the logical operation unit includes:

a counter: the switching value signal processing circuit is used for respectively receiving the two processor state signals and outputting a switching value signal;

and the logic arithmetic unit receives the switching value signal, compares and calculates the switching value signal and controls the state output signal.

The counter is used as the output of the state switching value, so that the operation comparison of the logic arithmetic unit is facilitated, the operation structure of the device is simplified, and the operation efficiency of the device is improved.

The further optimized technical scheme is as follows: it still includes:

and the laser power meter is used for detecting the output power state of the semiconductor laser and outputting the power state to the logic operation unit.

The laser power meter detects the power state of the laser, when the laser power is larger than or equal to the threshold power P, the laser power meter outputs a high level, and when the laser power is lower than the threshold power P, the laser power meter outputs a low level, and the power state triggers the logic operation unit to realize the control of the multiplexer.

The second technical scheme of the invention is that the device is used in a laser system: it includes the above-mentioned reliable control semiconductor laser output power device, also includes

The laser driving power supply receives a power output signal of the power signal control unit and is connected with the multiplexer;

the semiconductor laser is connected with the multiplexer;

in actual operation, the multiplexer selects whether or not to cut off the circuit between the laser drive power supply and the semiconductor laser in accordance with the state of the emergency stop.

The further optimized technical scheme is as follows: the laser power meter is used for detecting the output power state of the semiconductor laser and outputting the power state to the logic operation unit.

The further optimized technical scheme is as follows: the laser power meter also comprises a spectroscope which is used for dividing the laser output by the semiconductor laser into reflected laser and working laser, and the reflected laser is output to the laser power meter. The laser power is detected by using the spectroscope for light splitting, so that the normal working state of the laser is not influenced, and the state of the laser output power can be detected.

The third technical scheme of the invention is a method for reliably controlling the output power of a semiconductor laser: and comparing and judging the emergency stop and/or fault state by using the laser power signals and the state signals of the at least two processors, controlling the on-off of the laser driving power supply and selecting the path of the current signal of the multiplexer.

The further optimized technical scheme is as follows: the status signal includes an operating status of the at least two processors and/or a semiconductor laser output power status.

The further optimized technical scheme is as follows: the operation states of at least two processors and the output power state of the semiconductor laser are realized by comparison and operation of a logic operation unit.

The invention controls the laser power by at least two processors which work independently, can effectively avoid wrong laser power output when any processor has software or hardware faults, and can not only use software to control the laser output power, but also meet the requirement of safety specification compared with the traditional scheme.

The threshold power P of the laser power meter can meet the international requirements on laser safety classification, and lasers with the threshold power P smaller than 5mW are generally selected to be classified into a type of lasers which are harmless to skin and human eyes and cannot cause combustible ignition after long-term irradiation.

The laser emission is stopped after the laser signal for emergency stop is received in a normal state without disconnecting the input of a laser driving power supply, and the laser emission is ended by a pure hardware device which consists of a multiplexer, a logic arithmetic unit, a timer and a laser power meter when the processor fails.

The longest time from the laser signal stopping to the laser emission stopping in the fault state can be controlled and is a fixed value N, and the out-of-control time from the abnormal state to the laser emission stopping can be controlled by changing the value N.

The input end of the semiconductor laser is short-circuited with the ground in a fault state or a shutdown state, so that the semiconductor laser can be protected from being damaged by overcurrent voltage and static electricity.

Drawings

Fig. 1 is a schematic structural diagram ofprior art scheme 1.

Fig. 2 is a schematic structural diagram ofprior art scheme 2.

FIG. 3 is a schematic structural diagram of an embodiment of the present invention.

FIG. 4 is a schematic diagram of a multiplexer.

FIG. 5 is a schematic diagram of a beam splitter optical path.

Detailed Description

The following detailed description is provided for the purpose of explaining the claimed embodiments of the present invention so that those skilled in the art can understand the claims. The scope of the invention is not limited to the following specific implementation configurations. It is intended that the scope of the invention be determined by those skilled in the art from the following detailed description, which includes claims that are directed to this invention.

As shown in fig. 3, in the first embodiment: the device of the present invention includes anemergency stop switch 310, which is a broad-sense emergency stop laser switch, and may be a laser stop switch, a safety interlock switch, etc., a key switch, a button, etc., having a function similar to stopping laser emission, or a stop signal from other devices, whose specific specification and model are not related to the method of the present invention.

The output signals of the emergency stop switch are respectively connected with theprocessor 311 and theprocessor 312; theprocessor 311 and theprocessor 312 have the same power output terminal of the laser driving power supply and a status output terminal, specifically, a general-purpose or dedicated arithmetic and control unit, theprocessor 311 and theprocessor 312 operate independently without any relation, each processor has at least one input port a, two output ports are respectively a status output terminal m and a power output terminal n, but not limited to only these three interfaces. Theprocessor 311 and the input interface a of theprocessor 312 are connected to theemergency stop switch 310 at the same time;

acounter 307 and a counter 308, which are a timing device having input control terminals a, b, c and an output port q1, a register CT; the three input control terminals are a power state input terminal a, a processor state input terminal b and an emergency stop switch state input terminal c.

The digital comparator 313 has at least two input ports B, C and oneoutput interface q 2. Port B receives the digitized analog power control signal fromprocessor 311 and port C receives the digitized analog power control signal fromprocessor 312, and transmits it to output port q2 if the input contents of port B and port C are the same, and outputs zero at output port q2 if the input contents of port B and port C are not the same.

Thelaser power meter 309 is a laser power detection device that measures a part of the laser light split by thebeam splitter 304, and outputs a high level when the laser power is equal to or higher than the threshold power P, and outputs a low level when the laser power is lower than the threshold power P. The laser power detection device only detects the average value of the laser power and other parameters, such as wavelength, divergence angle, frequency and pulse, are irrelevant to the method. The threshold power is typically set at 5 milliwatts, the specific value of which is independent of the method described in the present invention in relation to the safety standard being met.

The relationship of the specific signals is: the output port n of theprocessor 311 is connected to the b port of thecounter 307; the output port n of theprocessor 312 is connected to the b output port of the counter 308. The m-ports ofprocessors 311 and 312 output digitized analog values for controlling laser output power; the m ports of theprocessors 311 and 312 are connected to the B port and the C port of the digital comparator 313, respectively, and the n ports of theprocessors 311 and 312 continuously output positive pulse widths in a period less than 0.5 × T when the laser is normally emitted. When any one of theprocessors 311 and 312 receives a laser stop request from theemergency stop switch 310, the digitized analog value at the m-port output becomes zero, and the n-port output continues to be low. The operating frequency, structure, software version of theprocessor 311 and theprocessor 312 are not relevant to the method of the present invention. Digitized analog values refer to the analog signals that will need to be digitized for transmission by a binary method.

The output q2 of the digital comparator 313 is connected to the digital-to-analog converter 305.

The output end of thelaser power meter 309 is respectively connected with the a ports of thecounter 307 and the counter 308;

two input terminals of thelogic operator 306 are connected to the output terminals q1 of thecounter 307 and the counter 308, respectively. The output q1 of thecounter 307 and the counter 308 enters thelogic operator 306, and the inputs of the two are summed and then output to themultiplexer 302. The minimum value of N needs to be larger than 2, the maximum value is not limited, and the value range of the period T only influences the interval time from the abnormal state to the laser stop, and is irrelevant to the method.

Themultiplexer 302 is a single-way double-throw switch as shown in fig. 4, and has a common terminal for connecting with thesemiconductor laser 303, a normally closed terminal for connecting with the ground, a normally open terminal for connecting with the laser drivingpower supply 302, and a control terminal for connecting with thelogic operator 306. When the control end of themultiplexer 302 inputs a low level or hangs up, the common end is connected with the normally closed end to short the input of thesemiconductor laser 303 to the ground, and when the control end inputs a high level, the common end is connected with the normally open end to connect thesemiconductor laser 303 and the laser drivingpower supply 301. Themultiplexer 302 may be a semiconductor switch, a mechanical switch, etc. and its specific implementation is not relevant to the method of the present invention.

Example two: the device of the first embodiment is arranged in a laser device to form a system, specifically, amultiplexer 302 is connected between a laser drivingpower supply 301 and asemiconductor laser 303, a common terminal is connected with thesemiconductor laser 303, a normally closed terminal is connected with a ground wire, and a normally open terminal is connected with the laser drivingpower supply 302. Abeam splitter 304 is disposed on a laser output light path of thesemiconductor laser 303, and as shown in fig. 5, thebeam splitter 304 is a device capable of splitting incident laser into two beams, wherein theinput laser 401, the reflectedlaser 402, and the working laser 340; the size of the substrate film layer is independent of the method of the invention, wherein the reflected laser is 1-0.001% of the input laser, and the working laser is 99-99.99% of the input laser.

Thelaser power meter 309 measures the portion of the laser light split by thebeam splitter 304.

The control strategy of the device is to compare and judge the emergency stop and/or fault state by using the laser power signals and the state signals of the two processors, control the on-off of the laser driving power supply and select the passage of the current signal of the multiplexer. The status signal includes the operating status of the two processors and/or the semiconductor laser output power status. The operating states of the two processors and the output power state of the semiconductor laser are realized by comparison and operation of a logic operation unit.

The specific method for realizing control according to different states comprises the following steps:

shutdown state: the common terminal of themultiplexer 302 is connected to the normally closed terminal, and the input of thesemiconductor laser 303 is connected to the ground.

Initial or power-up state:

s100, thesemiconductor laser 303 does not output laser;

s101 thelaser power meter 309 outputs a low level;

s102, thecounter 307 and the counter B308 stop counting, the CT value is smaller than N, and the output end q1 outputs high level;

s103 thelogic operator 306 outputs a high level;

s104, the common end of themultiplexer 302 is connected with the normally open end;

s105, connecting a laser drivingpower supply 301 with asemiconductor laser 303;

s106, the laser is in a state of emitting at any time.

And (3) normal working state:

s200, theprocessor 311 and theprocessor 312 send laser power intensity signals from m ports, and n ports output positive pulse width in T period

S201, after comparing the values of the port B and the port C, the digital comparator 313 transmits the same q2 port to the analog-digital converter 305;

S202A/D converter 305 output port q2 outputs corresponding analog quantity value

S203 the laser drivingpower supply 301 starts to output a constant current;

s204 thesemiconductor laser 303 starts emitting laser light;

s205, thelaser power meter 309 outputs a high level after detecting that the laser power exceeds 5 milliwatts;

s206, thecounter 307 and the counter 308 start to count time but the timer continuously outputs high level because the port b continuously inputs a clear pulse;

s207, the laser driving current 301 is connected with thesemiconductor laser 303;

s208 thesemiconductor laser 303 continues emitting laser light normally.

Processor fault status:

s300, theprocessor 311 or theprocessor 312 abnormally fails to correctly transmit periodic pulses from the n port in time;

the q1 port outputs low level after thecounter 307 or the counter B308 of the S301 is larger than the N value;

the output port of the S302logical operator 306 outputs a low level;

in S303, the common terminal of themultiplexer 302 is grounded, and thesemiconductor laser 303 is disconnected from the laser drivingpower supply 301 to stop emitting laser light.

Normal emergency stop state:

s400 theemergency stop switch 310 outputs an emergency stop signal;

s401, after theprocessor 311 and theprocessor 312 receive the laser stop signal, the m port outputs zero and the n port outputs a stop output positive pulse and keeps low level continuously;

s402, the analog signal output by the digital-to-analog converter 305 is zero;

s403 the laser drivingpower supply 301 outputs a driving current of zero;

s404 thesemiconductor laser 303 stops emitting laser light;

s405, outputting a low level when the measured power of thelaser power meter 309 is smaller than the threshold power P;

s406, the register CT of thecounter 307 and the counter 308 stops accumulating;

theS407 multiplexer 302 common remains connected to the normally open end without disconnecting the laser drive power supply from the semiconductor laser.

Emergency stop state at fault:

s500 theemergency stop switch 310 outputs an emergency stop signal;

s501, when theprocessor 311 or theprocessor 312 fails, the processor cannot normally output a zero value from the port m or stop outputting a periodic pulse at the output end n;

s502 the input ports c of thecounter 307 and the timer 308 are at low level;

s503, after the register CT values of thecounter 307 and the counter 308 are continuously increased to be larger than N, the output end q1 is at a low level;

s504 thelogic operator 306 outputs a low level to connect the common terminal of themultiplexer 302 to ground;

s505 the laser drivingpower supply 301 disconnects thesemiconductor laser 303 and thesemiconductor laser 303 stops emitting laser light.

Claims (10)

Translated fromChinese

1.一种可靠控制半导体激光器输出功率装置，它包括紧急停止开关，其特征在于，它还包括：1. a reliable control semiconductor laser output power device, it comprises an emergency stop switch, it is characterized in that, it also comprises:至少两个处理器，分别用于接收紧急停止开关控制信号，输出激光功率信号以及状态信号；at least two processors, respectively used for receiving the emergency stop switch control signal, and outputting the laser power signal and the status signal;功率信号控制单元，用于接收两个处理器的功率信号，比较功率信号，控制功率输出信号；a power signal control unit, used for receiving the power signals of the two processors, comparing the power signals, and controlling the power output signal;逻辑运算单元，用于分别接收至少两个处理器状态信号，比较状态信号，控制状态输出信号；The logic operation unit is used to respectively receive at least two processor state signals, compare the state signals, and control the state output signals;多路选择器，用于接收控制状态输出信号，选择电流信号的通路。The multiplexer is used to receive the control state output signal and select the path of the current signal.2.如权利要求1所述可靠控制半导体激光器输出功率装置，其特征在于所述功率信号控制单元包括：2. The device for reliably controlling the output power of a semiconductor laser according to claim 1, wherein the power signal control unit comprises:比较器：用于接收两个处理器的激光功率信号，判断两个功率信号，输出功率信号；Comparator: used to receive the laser power signals of the two processors, judge the two power signals, and output the power signal;数字模拟转换器，用于将接收到的输出功率数字信号转化为模拟信号予以输出。The digital-to-analog converter is used to convert the received output power digital signal into an analog signal for output.3.如权利要求1所述可靠控制半导体激光器输出功率装置，其特征在于所述逻辑运算单元包括：3. The device for reliably controlling the output power of a semiconductor laser according to claim 1, wherein the logic operation unit comprises:计数器：用于分别接收两个处理器状态信号，输出开关量信号；Counter: used to receive two processor status signals respectively, and output switch signal;逻辑运算器，接收开关量信号，比较运算开关量信号后，控制状态输出信号。The logic operator receives the digital signal, compares and operates the digital signal, and outputs the signal in the control state.4.如权利要求1或3所述可靠控制半导体激光器输出功率装置，其特征在于它还包括：4. The device for reliably controlling the output power of a semiconductor laser according to claim 1 or 3, characterized in that it also comprises:激光功率计，用于检测半导体激光器的输出功率状态，并输出功率状态到逻辑运算单元。The laser power meter is used to detect the output power status of the semiconductor laser, and output the power status to the logic operation unit.5.一种可靠控制半导体激光器输出功率系统，其特征在于它包括如权利要求1所述可靠控制半导体激光器输出功率装置，5. a reliable control semiconductor laser output power system is characterized in that it comprises the reliable control semiconductor laser output power device as claimed in claim 1,激光驱动电源，接收功率信号控制单元的功率输出信号，连接多路选择器；The laser drive power supply receives the power output signal of the power signal control unit, and is connected to the multiplexer;半导体激光器，连接多路选择器。Semiconductor laser, connected to multiplexer.6.如权利要求5所述可靠控制半导体激光器输出功率系统，其特征在于它还包括激光功率计，用于检测半导体激光器的输出功率状态，并输出功率状态到逻辑运算单元。6. The system for reliably controlling the output power of a semiconductor laser according to claim 5, characterized in that it further comprises a laser power meter for detecting the output power status of the semiconductor laser and outputting the power status to the logic operation unit.7.如权利要求6所述可靠控制半导体激光器输出功率系统，其特征在于它还包括分光镜，用于将半导体激光器输出的激光分成反射激光和工作激光，反射激光输出到激光功率计。7. The system for reliably controlling the output power of a semiconductor laser according to claim 6, characterized in that it further comprises a beam splitter for dividing the laser output from the semiconductor laser into a reflected laser and a working laser, and the reflected laser is output to a laser power meter.8.一种可靠控制半导体激光器输出功率方法，其特征是，利用至少两个处理器的激光功率信号以及状态信号，比较判断紧急停止和/或故障状态，控制激光驱动电源通断以及选择多路选择器电流信号的通路。8. A method for reliably controlling the output power of a semiconductor laser, characterized in that, using the laser power signals and state signals of at least two processors, comparing and judging emergency stop and/or fault states, controlling the on-off of the laser drive power supply and selecting multiple channels Path for selector current signal.9.如权利要求8所述可靠控制半导体激光器输出功率方法，其特征是，所述状态信号包括至少两个处理器的运行状态信号和/或半导体激光器输出功率状态熊信号。9 . The method for reliably controlling the output power of a semiconductor laser according to claim 8 , wherein the status signal includes the running status signal of at least two processors and/or the output power status signal of the semiconductor laser. 10 .10.如权利要求8所述可靠控制半导体激光器输出功率方法，其特征是，至少两个处理器的运行状态，半导体激光器输出功率状态是通过逻辑运算单元比较运算实现。10 . The method for reliably controlling the output power of a semiconductor laser according to claim 8 , wherein the operating states of at least two processors and the output power states of the semiconductor laser are realized by a comparison operation of a logic operation unit. 11 .

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