Light-sensing external trigger signal output device for laser far-field parameter analysis and use method thereof

Abstract

The invention discloses a light-sensing external trigger signal output device for laser far-field parameter analysis, comprising: a light signal detector, used for collecting laser signals irradiated on a target plate and outputting a pulse current signal; a signal primary amplification module, used for converting the pulse current signal into a pulse voltage signal and amplifying the pulse voltage signal; a signal superposition amplification module, used for amplifying the pulse voltage amplification signal output by the signal primary amplification module again; a laser pulse signal judgment module, comprising a comparator, used for setting a signal judgment threshold value, the comparator being connected to a monostable trigger, and the monostable trigger sending a trigger signal when the pulse signal is greater than the signal judgment threshold value set by the comparator; an MCU main control module, used for interrupt processing, trigger signal delay and output frequency setting, trigger signal output and transmitting a timing control signal to an imaging camera; a power management module, connected to an external power supply and supplying power to the remaining modules.

Description

Technical Field

[0001] The present invention belongs to the technical field of signal transmission, and in particular relates to a light-sensing external trigger signal output device for laser far-field parameter analysis and a use method thereof. Background Art

[0002] In the far-field laser parameter analysis, the low repetition rate laser emits laser light onto the far-field target plate, and the imaging camera is placed near the target plate to capture the laser spot image on the target plate for parameter analysis. Since the laser being tested has a low pulse laser frequency and a narrow pulse width (laser period is at the ms level and pulse width is at the ns level), it is necessary to perform timing control between the laser being tested and the imaging camera to ensure that each exposure of the imaging camera covers the laser pulse width so that the imaging camera can capture the laser spot image normally.

[0003] The existing timing control method is to connect the laser and the imaging camera's external trigger interface through a hard wire and send an external trigger signal through a signal generator for synchronization control. During the laser far-field parameter analysis, the laser and the imaging camera are far apart (possibly several kilometers away). If hard wired, it is difficult to make several kilometers of hard wires. The trigger signal may be attenuated to a certain extent after long-distance transmission and is easily interfered with, resulting in the inability to achieve synchronization. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a light-sensitive external trigger signal output device for laser far-field parameter analysis and a method for using the same. During the laser far-field parameter test, the laser to be tested irradiates a target plate, which can trigger the device to output a trigger signal with the same frequency as the laser light output to an imaging camera to complete the exposure trigger. The delay time interval between the detection of laser irradiation and the output of the trigger signal can be set according to factors such as the pulse width of the light and the distance of the far field, to ensure that the camera can normally capture the laser spot image.

[0005] The present invention achieves this object through the following technical solutions:

[0006] A light-sensing external trigger signal output device for laser far-field parameter analysis, comprising:

[0007] An optical signal detector, used to collect the laser signal irradiated on the target plate and output a pulse current signal;

[0008] The first-level signal amplification module is used to sample the pulse voltage signal of the pulse current signal output by the optical signal detector through a sampling resistor and amplify the pulse voltage signal;

[0009] The signal superposition amplification module is used to amplify the pulse voltage amplification signal output by the first-level signal amplification module again;

[0010] The laser pulse signal judgment module includes a comparator for setting a signal judgment threshold value, the comparator is connected to a monostable trigger, and when the pulse signal is greater than the signal judgment threshold value set by the comparator, the monostable trigger sends a trigger signal;

[0011] The MCU main control module is used for interrupt processing, trigger signal delay and output frequency setting, trigger signal output, interrupt processing after receiving the trigger signal sent by the laser pulse signal judgment module, and transmit the timing control signal to the imaging camera;

[0012] The power management module is connected to an external power supply and supplies power to the optical signal detector, the first-level signal amplification module, the signal superposition amplification module, the laser pulse signal judgment module and the MCU main control module.

[0013] Furthermore, in the first-stage signal amplification module, the pulse current signal output by the optical signal detector is connected to the analog ground through a sampling resistor, the sampling resistor is connected in parallel with a diode and an inductor, the anode of the diode is connected to the analog ground, and the cathode of the diode is connected to the anode of the amplifier.

[0014] Furthermore, in the signal superposition and amplification module, a pull-up resistor and a pull-down resistor are provided at the signal input end to prevent misjudgment caused by interference signals, and the amplifier is used to superimpose and amplify the input voltage signal.

[0015] Furthermore, in the laser pulse signal judgment module, a series capacitor is provided at the comparator input end to filter out the DC signal. The signal output by the comparator is connected to the first monostable trigger. The first monostable trigger is provided with a differential circuit to control the laser frequency pulse width holding time. The output signal of the first monostable trigger is input to the second monostable trigger. At the same time, the MCU main control module inputs the delay signal to the second monostable trigger. The second monostable trigger outputs a trigger signal that triggers the MCU main control module program to run. The second monostable trigger controls the output signal interval time by setting a differential circuit.

[0016] Furthermore, the power management module includes an analog power supply and a digital power supply. The analog power supply is provided with a plurality of linear regulators to step down the input power supply and provide power supply of corresponding specifications to the optical signal detector, the first-level signal amplification module, the signal superposition amplification module and the digital power supply circuit. A filter is provided at the input end and connected to the protective ground, and the output end is connected to the analog ground and a capacitor is provided for voltage stabilization. The digital power supply is provided with a plurality of linear regulators to step down the input power supply and provide power supply of corresponding specifications to the laser pulse signal judgment module and the MCU main control module. A parallel capacitor group is provided at the input end of the circuit and connected to the digital ground, and the output end is connected to the digital ground and a capacitor is provided for voltage stabilization.

[0017] The present invention also provides a method for using the above-mentioned optical sensing external trigger signal output device for laser far-field parameter analysis, comprising the following contents:

[0018] According to the light output frequency of the laser, the output frequency of the trigger signal output of the light-sensing external trigger signal output device is set;

[0019] Set the trigger signal delay time of the MCU main control module according to the laser's light frequency, laser pulse width, and far-field distance;

[0020] Select the filter of the optical signal detector according to the output wavelength of the laser to ensure that it will not be interfered by other light and noise.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The traditional hard-wired synchronization method cannot achieve the timing control of long-distance equipment. The present invention provides a light-sensing external trigger signal output device for laser far-field parameter analysis. The light-sensing technology solves the long-distance timing control between the laser and the imaging camera during the laser far-field test. During the low-repetition-rate laser far-field test, the laser and the imaging camera can achieve precise timing control at a distance of several kilometers. After the laser is irradiated, the signal detection can be completed in a very short time (ns level), and the detection response speed is fast, ensuring that each exposure of the imaging camera covers the laser pulse width. In addition, the functional modules in the present invention can be integrated on a circuit board through circuit design to further reduce the size of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0024] Figure 1 This is a schematic diagram of the use and arrangement of the light-sensitive external trigger signal output device of the present invention;

[0025] Figure 2 This is a circuit diagram of a signal first-stage amplification module of a light-sensing external trigger signal output device of the present invention;

[0026] Figure 3 This is a circuit diagram of a signal superposition and amplification module of a light-sensing external trigger signal output device of the present invention;

[0027] Figure 4 This is a circuit diagram of a laser pulse signal determination module of a light-sensing external trigger signal output device of the present invention;

[0028] Figure 5 This is a circuit diagram of the MCU main control module of the light-sensing external trigger signal output device of the present invention;

[0029] Figure 6 The analog power supply circuit diagram of the light-sensing external trigger signal output device of the present invention;

[0030] Figure 7 This is a digital power supply circuit diagram of the light-sensitive external trigger signal output device of the present invention. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0032] The light-sensitive external trigger signal output device of the present invention is mainly used for the timing control of the long distance (several kilometers away) between the low repetition rate laser (low frequency, narrow pulse width) and the imaging camera during the laser far-field test, ensuring that each exposure of the imaging camera covers the laser pulse width and can normally capture the laser spot image. Figure 1 As shown, the device is installed on a far-field target plate. When the laser irradiates the target plate, it triggers the optical signal detector to generate a pulse current signal. The current is converted into a pulse voltage signal through a sampling resistor. After the signal is amplified and processed to confirm that the optical signal is detected, the camera trigger signal consistent with the laser light frequency can be delayed to output to the imaging camera to complete the camera exposure trigger. The power management module provides the required working power of different voltages for the system.

[0033] The device comprises an optical signal detector, a signal primary amplification module, a signal superposition amplification module, a laser pulse signal judgment module, an MCU main control module and a power management module.

[0034] The first-level signal amplification module is used for collecting laser pulse signals. When the laser is projected onto the detector, the detector outputs a pulse current signal. The circuit is as follows Figure 2 As shown, the pulse voltage signal is sampled through the sampling resistor (300+1K)Ω, and the sampling range is about 1mV to 30mV. The diode 1N4148 and the inductor 100uH are connected in parallel mainly to reduce signal oscillation. The amplifier uses the AD8067 voltage feedback amplifier, and the pulse voltage signal is amplified in phase by the operational amplifier AD8067. Amplifier formula:

[0035] Amplified output voltage: U out =(1+R i / R f )in ;

[0036] Magnification: A = 1 + R i / R f .

[0037] The voltage signal is collected and amplified by the AD8067 high-speed operational amplifier and then further processed by the back-end signal superposition and amplification module.

[0038] The circuit design purpose of the signal superposition amplification module is to avoid noise interference. By setting a threshold, noise is not easy to come in according to the threshold judgment to avoid misjudgment. Using signal superposition amplification to obtain large pulse signals can better judge the authenticity of pulse signals. The initial sampling voltage signal is superimposed and amplified 200 times by the high-precision operational amplifier AD8067. If the long-distance signal is slightly weak, in order to allow the signal to better pass through the threshold, the gain is increased to 200 times. By collecting large pulse signals, it is judged whether there is a laser pulse to avoid collecting noise interference signals. The voltage signal CHS amplified by the operator is judged and processed by the back-end laser pulse signal judgment module. The circuit structure of the signal superposition amplification module is as follows Figure 3 As shown, a pull-up resistor R16 and a pull-down resistor R17 are provided at the signal input end to prevent misjudgment caused by interference signals.

[0039] The circuit of the laser pulse signal judgment module is as follows: Figure 4 As shown, the superimposed amplified voltage signal transmitted by the initial signal acquisition amplification of the front end passes through the comparator MAX913 and is compared with the set reference value 100MV threshold. The 100V reference value is determined by adjusting the potentiometer. The main function is to filter out noise and prevent misjudgment. When the threshold value is set, the signal comes in and the noise is filtered out. A series capacitor is set at the input end of the comparator to shield DC signal interference.

[0040] If the pulse signal value is greater than the threshold, the comparator will output a high level, which is triggered by the rising edge of the monostable trigger SN74LV221APW, outputting a square wave with a pulse width of 10us and a level of 5V, and at the same time triggering the rising edge interrupt request of the MCU main control module.

[0041] The signal output by the comparator is connected to the first monostable trigger U8A. The first monostable trigger U8A sets a differential circuit to control the frequency pulse width holding time of the laser. The output signal of the first monostable trigger U8A is input to the second monostable trigger U8B. At the same time, the MCU main control module inputs the delay signal to the second monostable trigger U8B. The second monostable trigger U8B outputs a trigger signal that triggers the MCU main control module program to run. The second monostable trigger U8B controls the output signal interval time by setting a differential circuit.

[0042] MCU main control module circuit Figure 5As shown, the microcontroller uses the STM32G474RET6 in LQFP64 package. The advantage of this microcontroller is the high-performance ARM Cortex-M4 32-bit RISC core. The operating frequency is up to 170MHZ, and the speed is good. STM32G474RET6 provides 5 fast 12-bit ADCs (5Msps), 7 comparators, 6 operational amplifiers, 7 operational amplifier DAC channels (3 external and 4 internal), an internal voltage reference buffer, a low-power buffer RTC, 2 general 32-bit timers, 3 16-bit dedicated timers, 7 general 16-bit timers, and 16-bit low-power timers. The main functions of the MCU main control module are interrupt processing, trigger signal delay and output frequency setting, and trigger signal output. As the main control integrated processing unit, it can judge the frequency according to the received laser pulse and generate a trigger signal of the same frequency. The fixed delay between the trigger signal and the received laser pulse signal can ensure that the laser pulse width range can be covered during each camera exposure period. After the laser pulse signal judgment circuit generates an interrupt Q10us, it outputs a 10us pulse width 5V level square wave to the camera according to the set trigger signal delay time and frequency to complete the camera exposure trigger.

[0043] The power management module includes an analog power circuit and a digital power circuit.

[0044] like Figure 6 As shown, the analog power supply circuit uses the linear regulator ADP7104. The power supply 11Vin input is provided by a DC power supply module. The power supply noise is slightly large, and a fifth-order low-pass filter is required to effectively filter out high-frequency noise. After the fifth-order low-pass filter, the output 11V is used as the input power supply for the front-end board. At the same time, the power ground is processed separately, and the input ground and output ground are separated, so that the power supply signal noise reduction effect will be better. The input end is connected to the protection ground PGND through a low-pass filter, and the output end is connected to the analog ground AGND and a 4.7uf capacitor is set for voltage regulation. The power supply output by the linear regulator U1 is used to power the digital power supply circuit, and the power supply output by the linear regulator U2 is used to power the optical signal detector, the first-level signal amplification module, and the signal superposition amplification module.

[0045] Digital power circuit such as Figure 7 As shown, the circuit is processed separately from the analog power supply to reduce signal interference. A parallel capacitor group is provided at the input end and connected to the digital ground DGND. The capacitor group is used to reduce the impact of power supply fluctuations. The power output by the linear regulator U3 is used to power the laser pulse signal judgment module. The power output by the linear regulator U4 is used to power the MCU control module. The output end is connected to a 4.7uf capacitor for voltage regulation and connected to the digital ground DGND.

[0046] When the light-sensitive external trigger signal output device of the present invention is used, the output frequency of the trigger signal output of the light-sensitive external trigger signal output device is set according to the light output frequency of the laser; the trigger signal delay time of the MCU main control module is set according to the light output frequency of the laser, the laser pulse width time, and the far-field distance; and the filter of the light signal detector is selected according to the light output wavelength of the laser to ensure that it will not be interfered by other light and noise.

[0047] The present invention has been described in detail above through embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. Anyone who utilizes the technical solution described in the present invention, or a technician in the field, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and protection scope of the present invention to achieve the above technical effects, or makes equal changes and improvements to the scope of application, shall still belong to the scope of protection covered by the patent of the present invention. It should be noted that in order to make a clear statement, the description of some components and processes that have no direct and obvious connection with the scope of protection of the present invention but are known to those skilled in the art are omitted in the description of the present invention.

Claims

1. A light-sensing external trigger signal output device for laser far-field parameter analysis, characterized in that: include: An optical signal detector, used to collect the laser signal irradiated on the target plate and output a pulse current signal; The first-level signal amplification module is used to sample the pulse voltage signal of the pulse current signal output by the optical signal detector through a sampling resistor and amplify the pulse voltage signal; The signal superposition amplification module is used to amplify the pulse voltage amplification signal output by the first-level signal amplification module again; The laser pulse signal judgment module includes a comparator for setting a signal judgment threshold value, the comparator is connected to a monostable trigger, and when the pulse signal is greater than the signal judgment threshold value set by the comparator, the monostable trigger sends a trigger signal; The MCU main control module is used for interrupt processing, trigger signal delay and output frequency setting, trigger signal output, interrupt processing after receiving the trigger signal sent by the laser pulse signal judgment module, and transmit the timing control signal to the imaging camera; The power management module is connected to an external power supply and supplies power to the optical signal detector, the first-level signal amplification module, the signal superposition amplification module, the laser pulse signal judgment module and the MCU main control module.

2. The optical sensing external trigger signal output device for laser far-field parameter analysis according to claim 1, characterized in that: In the first-level signal amplification module, the pulse current signal output by the optical signal detector is connected to the analog ground through a sampling resistor, the sampling resistor is connected in parallel with a diode and an inductor, the anode of the diode is connected to the analog ground, and the cathode of the diode is connected to the anode of the amplifier.

3. The optical sensing external trigger signal output device for laser far-field parameter analysis according to claim 1, characterized in that: In the signal superposition and amplification module, pull-up resistors and pull-down resistors are set at the signal input end to prevent misjudgment caused by interference signals, and the amplifier is used to superimpose and amplify the input voltage signal.

4. The optical sensing external trigger signal output device for laser far-field parameter analysis according to claim 1, characterized in that: In the laser pulse signal judgment module, a series capacitor is set at the input end of the comparator to filter out the DC signal. The signal output by the comparator is connected to the first monostable trigger. The first monostable trigger is set with a differential circuit to control the laser frequency pulse width holding time. The output signal of the first monostable trigger is input to the second monostable trigger. At the same time, the MCU main control module inputs the delay signal to the second monostable trigger. The second monostable trigger outputs a trigger signal that triggers the MCU main control module program to run. The second monostable trigger controls the output signal interval time by setting a differential circuit.

5. The optical sensing external trigger signal output device for laser far-field parameter analysis according to claim 1, characterized in that: The power management module includes an analog power supply and a digital power supply. The analog power supply is provided with multiple linear regulators to step down the input power supply and provide power supply of corresponding specifications to the optical signal detector, the first-level signal amplification module, the signal superposition amplification module and the digital power supply circuit. A filter is provided at the input end and connected to the protective ground, and the output end is connected to the analog ground and a capacitor is provided for voltage stabilization. The digital power supply is provided with multiple linear regulators to step down the input power supply and provide power supply of corresponding specifications to the laser pulse signal judgment module and the MCU main control module. A parallel capacitor group is provided at the input end of the circuit and connected to the digital ground, and the output end is connected to the digital ground and a capacitor is provided for voltage stabilization.

6. A method for using the optical sensing external trigger signal output device for laser far-field parameter analysis as claimed in claim 1, characterized in that: Includes the following: According to the light output frequency of the laser, the output frequency of the trigger signal output of the light-sensing external trigger signal output device is set; Set the trigger signal delay time of the MCU main control module according to the laser's light frequency, laser pulse width, and far-field distance; Select the filter of the optical signal detector according to the output wavelength of the laser to ensure that it will not be interfered by other light and noise.

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