Semiconductor laser system and back light protection method

Abstract

The application discloses a kind of semiconductor laser system and return light protection method.It includes laser, transmission fiber, processing head and drive control system, drive control system includes drive module and control module.Laser chip emits laser, and after shaping mirror group is shaped, it is coupled into transmission fiber, and from transmission fiber to processing head;Drive module provides operating current to laser chip;Control module monitors the operating voltage of laser chip in real time, when the operating voltage monitored exceeds preset safety threshold, sends off signal to drive module;Drive module receives off signal and cuts off the drive current output to laser chip.The application does not need additional optical detector and expensive magneto-optical isolator, directly monitors laser chip voltage parameter, only realizes return light protection by circuit module, simple structure, easy to integrate, low in cost, response is fast, can identify return light in time and execute protection, avoid laser chip to suffer persistent damage.

Description

Technical Field

[0001] This application relates to the field of laser protection, and more particularly to a semiconductor laser system and a method for protecting against backlighting. Background Technology

[0002] Semiconductor lasers are widely used in industrial processing due to their advantages such as small size, high efficiency, and long lifespan. A typical semiconductor laser application system includes components such as the laser, transmission fiber, and processing head. The laser contains a built-in laser chip and a shaping mirror assembly. The laser emitted by the laser chip is transmitted by the shaping mirror assembly and coupled into the transmission fiber, from which the laser beam is output. After the laser beam is shaped by the processing head, it is applied to the material being processed for cutting, welding, and other processing operations.

[0003] In actual processing, when the material being processed is a highly reflective material such as steel, aluminum, or copper, the laser beam irradiating the workpiece surface will produce strong reflected light. This reflected light may be reflected back along the original optical path, passing through the processing head and transmission fiber, and finally returning to the laser chip inside the laser. This light returning along the original optical path is called backlight. After entering the active region of the laser chip, the backlight will severely interfere with the carrier distribution and recombination process inside the laser chip, causing abnormal changes in the electrical parameters of the laser chip, especially an abnormal increase in the operating voltage. Continuous backlight will cause permanent damage to the laser chip, seriously threatening the stability and reliability of the laser, and even leading to laser failure.

[0004] Therefore, there is an urgent need to provide a fast-responding and cost-effective backlight protection solution. Summary of the Invention

[0005] This application provides a semiconductor laser system that solves the problem in the prior art that semiconductor lasers cannot timely and reliably identify and implement rapid protection when backlight interference occurs.

[0006] In a first aspect, this application provides a semiconductor laser system, comprising: Laser, including laser chip and shaping lens assembly; Transmission fiber; Processing head; and The drive control system includes a drive module and a control module. in, The laser emitted by the laser chip is shaped by the shaping mirror group and then coupled into the transmission optical fiber, from which the laser beam is output to the processing head for emission. The driving module provides operating current to the laser chip; The control module monitors the operating voltage of the laser chip in real time. When the monitored operating voltage exceeds the preset safety threshold, it sends a shutdown signal to the drive module. After receiving the shutdown signal, the drive module cuts off the drive current output to the laser chip.

[0007] Optionally, the control module includes a control unit, a memory, and a voltage detection circuit, wherein the memory pre-stores the safety threshold. The voltage detection circuit acquires the operating voltage across the laser chip and transmits it to the control unit; The control unit compares the collected operating voltage with the safety threshold.

[0008] Optionally, the drive control system further includes a human-machine interaction module, wherein in response to a user inputting the safety threshold on the human-machine interaction module, the control unit stores the input safety threshold in a memory.

[0009] Optionally, a gyroscope sensor is also included. The gyroscope sensor collects the angle between the laser emitted by the semiconductor laser system and the normal direction of the workpiece, and transmits it to the control module. The control module determines the risk level of the backlight at the current processing angle based on the angle, and issues a warning through the human-machine interaction module when a high-risk angle is detected.

[0010] Optionally, the drive control system further includes a control power supply module and a drive power supply module, wherein the control power supply module supplies power to the control module and the drive power supply module supplies power to the drive module.

[0011] Secondly, this application provides a method for backlight protection, comprising the following steps: When processing a workpiece using the laser emitted from the semiconductor laser system, the operating voltage of the laser chip is monitored in real time. The monitored operating voltage is compared with the preset safety threshold. When the detected operating voltage exceeds the preset safety threshold, a shutdown signal is sent to the drive module to cut off the drive current output to the laser chip.

[0012] Optionally, before real-time monitoring of the laser chip's operating voltage, a system initialization step is also included: Adjust the drive current to a calibration current below the laser threshold current; The preset reference voltage is retrieved, and the detected voltage is compared with the reference voltage to determine whether the voltage detection circuit is working properly. If the deviation between the detected voltage and the reference voltage is within the allowable range, the self-test is deemed qualified and the system enters normal operating mode. If the deviation exceeds the allowable range, a fault alarm signal will be issued and the startup process will be stopped. The self-test will be re-executed after the hardware fault is investigated.

[0013] Optionally, the preset safety threshold is set according to the operating voltage value of the laser under different operating currents and different ambient temperatures. During the actual operation of the laser, the corresponding safety threshold voltage is retrieved according to the current operating current and ambient temperature.

[0014] Optionally, the real-time monitoring of the laser chip's operating voltage includes: The operating voltage across the laser chip is continuously collected according to a preset sampling frequency, wherein the sampling frequency is determined based on the laser's operating characteristics and the return light response time.

[0015] Optionally, after cutting off the drive current output to the laser chip, the method further includes a step of restoring normal operation: Investigate and eliminate the causes of the reflected light; The relationship between the operating voltage of the test laser chip and the safety threshold was compared. If the operating voltage does not exceed the safety threshold, the alarm state will be deactivated and the drive current output will be restored. If the operating voltage continues to exceed the safety threshold, re-investigate and resolve the problem. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This application provides an overall structural schematic diagram of a semiconductor laser system according to an embodiment of the present application. Figure 2 Provided for the embodiments of this application Figure 1 Detailed structural diagram of the drive control system; Figure 3 A schematic flowchart illustrating a method for backlight protection provided in this application embodiment; The labels in the diagram represent: 1-Control and drive system, 2-Laser, 3-Transmission fiber, 4-Processing head, 5-Collimating lens, 6-Focusing lens, 7-Processing material, 8-Human-machine interface module, 9-Control power supply module, 10-Control module, 11-Control unit, 12-Memory, 13-Drive power supply module, 14-Drive module, 15-Voltage detection circuit, 16-Resistor voltage divider network, 17-Filter circuit, 18-Operational amplifier circuit, 19-Analog-to-digital converter. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0022] like Figure 1 As shown, this embodiment provides a semiconductor laser system, including a laser 2, a transmission optical fiber 3, a processing head 4, and a drive control system 1.

[0023] Laser 2 incorporates a built-in laser chip and a shaping mirror assembly. The laser chip is a semiconductor laser chip that generates laser light under the drive of an electric current. The shaping mirror assembly includes multiple optical elements used to collimate and shape the laser light emitted by the laser chip, enabling it to be efficiently coupled into the transmission optical fiber 3.

[0024] The transmission fiber 3 is the core component of the fiber laser transmission system. One end of it is optically coupled to the output end of the laser 2, and the other end is connected to the processing head 4. The laser emitted by the laser chip is shaped by the shaping mirror group and then coupled into the transmission fiber 3. It is transmitted in the transmission fiber 3 by total internal reflection and finally output from the output end of the transmission fiber 3 to the processing head 4.

[0025] The processing head 4 is mounted on the actuator of the laser processing equipment, receiving the laser beam from the transmission fiber 3 and outputting it to the processing area. In this embodiment, the processing head 4 is equipped with a collimating lens 5 and a focusing lens 6. The collimating lens 5 converts the diverging laser beam output from the transmission fiber 3 into a parallel beam, and the focusing lens 6 focuses the parallel beam onto the surface of the processing material 7, forming a high-energy-density spot for laser processing operations such as cutting, welding, and marking.

[0026] The drive control system 1 is the core innovation of this invention, including a drive module 14 and a control module 10. The output terminal of the drive module 14 is connected to the positive and negative terminals of the laser chip of the laser 2, providing operating current to the laser chip. The drive module 14 adopts a constant current drive method, maintaining a constant output current under normal operating conditions to ensure stable light emission from the laser chip.

[0027] The control module 10 monitors the operating voltage of the laser chip in real time. During actual operation, when the material of the processing plate 7 is a high-reflectivity material such as steel, aluminum, or copper, the reflected light generated after the laser irradiates the workpiece surface may be reflected back along the original optical path, passing through the processing head 4 and the transmission fiber 3 back to the laser chip inside the laser 2. This reflected light, upon entering the active region of the laser chip, interferes with the carrier distribution and recombination rate, causing an abnormal increase in the operating voltage of the laser chip.

[0028] The control module 10 identifies the presence of reflected light by monitoring changes in the operating voltage in real time. When the detected operating voltage exceeds a preset safety threshold, the control module 10 immediately determines that there is a threat of reflected light and sends a shutdown signal to the drive module 14. Upon receiving the shutdown signal, the drive module 14 quickly cuts off the drive current output to the laser chip, causing the laser chip to stop working and interrupting the laser output. This blocks the generation and return path of reflected light, protecting the laser chip from continuous damage.

[0029] The working principle of this embodiment is based on the influence mechanism of reflected light on the voltage of a semiconductor laser chip. Specifically, when reflected light is incident on the active region of the laser chip, photons are absorbed, leading to an increase in carrier photogeneration. The increased non-equilibrium carrier concentration exacerbates carrier scattering, resulting in a decrease in carrier mobility. When the decrease in mobility exceeds the increase in carrier concentration, the resistivity of the semiconductor material increases, leading to an increase in the equivalent resistance of the laser chip. Under constant current driving conditions, according to Ohm's law, the increased equivalent resistance will cause an increase in the operating voltage across the chip. Furthermore, reflected light may also cause an increase in chip temperature, further altering carrier recombination and mobility, exacerbating the voltage rise. This invention utilizes this physical phenomenon to identify reflected light and trigger protection by monitoring voltage changes.

[0030] With the design of this embodiment, there is no need to install optical isolators in the optical path or external photodetectors. Backlight protection can be achieved through only the circuit module, which significantly reduces system cost and complexity, while ensuring fast and accurate protection response.

[0031] like Figure 2 As shown, this embodiment further details the internal structure of the drive control system 1 based on embodiment one.

[0032] The drive control system 1 includes a human-machine interaction module 8, a control power supply module 9, a control module 10, a drive power supply module 13, and a drive module 14.

[0033] The control module 10 includes a control unit 11, a memory 12, and a voltage detection circuit 15. The memory 12 is used to pre-store voltage safety threshold parameters and other system configuration parameters. The safety threshold parameters can be preset and stored in the memory 12 according to factors such as the laser chip model, rated operating current, and ambient temperature.

[0034] The voltage detection circuit 15 is used to acquire the operating voltage across the laser chip. For example... Figure 2 As shown, the voltage detection circuit 15 includes a resistor divider network 16, a filter circuit 17, an operational amplifier circuit 18, and an analog-to-digital converter 19.

[0035] The resistor divider network 16 consists of multiple precision resistors connected in series in a proportional manner, positioned between the positive and negative terminals of the laser chip. The laser chip typically operates at voltages ranging from several volts to tens of volts. The resistor divider network 16 reduces this voltage to a range suitable for subsequent circuit processing, such as a few tenths of a volt to a few volts, according to a set voltage division ratio. The resistor divider network 16 uses high-precision, low-temperature-drift resistors to ensure the stability and accuracy of the voltage division ratio.

[0036] The voltage signal after voltage division is input to filter circuit 17. Filter circuit 17 employs a low-pass filter design to filter out high-frequency noise and interference components in the voltage signal. During laser operation, factors such as the switching action of the drive current and electromagnetic interference introduce high-frequency noise into the voltage signal. Filter circuit 17 can effectively suppress this noise and extract the true operating voltage signal. Filter circuit 17 can be an RC filter circuit or an active filter circuit, with a suitable cutoff frequency selected based on the signal characteristics.

[0037] The filtered voltage signal is input to operational amplifier circuit 18. Operational amplifier circuit 18 amplifies and adjusts the voltage signal, bringing the signal amplitude to the optimal input range of analog-to-digital converter 19. Operational amplifier circuit 18 employs a high-precision operational amplifier with characteristics such as low offset voltage, low temperature drift, and high common-mode rejection ratio, ensuring accurate signal amplification. If necessary, operational amplifier circuit 18 can also perform level shifting to convert unipolar voltage signals into a voltage range suitable for the input of analog-to-digital converter 19.

[0038] The adjusted analog voltage signal is input to the analog-to-digital converter 19. The analog-to-digital converter 19 converts the analog voltage signal into a digital signal for digital processing by the control unit 11. The analog-to-digital converter 19 employs a high-resolution, high-sampling-rate ADC chip, such as a 12-bit or 16-bit resolution ADC, to ensure the accuracy of voltage acquisition. The sampling frequency of the analog-to-digital converter 19 is set according to the return light response time and system requirements, typically in the range of several kilohertz to tens of thousands of hertz, ensuring timely capture of rapid voltage changes.

[0039] The digital voltage signal output by the analog-to-digital converter 19 is transmitted to the control unit 11. The control unit 11 is implemented using a microcontroller (MCU) or a digital signal processor (DSP) and has functions such as data processing, logic judgment, and communication control. The control unit 11 continuously receives digital voltage signals from the analog-to-digital converter 19 and compares them in real time with the safety threshold parameters pre-stored in the memory 12.

[0040] The memory 12 can be a non-volatile memory such as EEPROM or Flash memory to ensure that the safety threshold parameters are not lost after power failure. The safety threshold stored in the memory 12 can be a single value or a multi-dimensional threshold table established according to different operating currents and ambient temperatures to achieve dynamic threshold configuration.

[0041] During the comparison and judgment process, when the operating voltage of multiple consecutive sampling points exceeds the safety threshold, the control unit 11 determines to trigger the protection mechanism and sends a shutdown signal to the drive module 14. The shutdown signal can be a digital signal or an analog signal, which is transmitted to the control input terminal of the drive module 14 through the output interface of the control unit 11. Setting a judgment condition of multiple consecutive points exceeding the threshold can avoid false triggering caused by accidental voltage spikes or interference.

[0042] The drive module 14 employs a switching power supply or a linear constant current power supply design, featuring a fast shutdown function. Upon receiving a shutdown signal, the internal power switching devices (such as MOSFETs or IGBTs) quickly turn off, cutting off the drive current output to the laser chip. The response time from receiving the shutdown signal to completely cutting off the current is typically in the microsecond to millisecond range, ensuring that the laser output is cut off before the reflected light causes serious damage.

[0043] The human-machine interface module 8 is connected to the control unit 11, providing operators with parameter input and system status display functions. The human-machine interface module 8 can take the form of a touchscreen, buttons and a display screen, or a host computer software interface. Operators can input or modify safety threshold parameters through the human-machine interface module 8. After receiving the input parameters, the control unit 11 stores them in the memory 12 as the basis for subsequent protection judgments. The human-machine interface module 8 can also display the current operating voltage, set safety thresholds, system operating status, alarm information, etc., facilitating operator monitoring of system operation.

[0044] The control power supply module 9 provides a stable operating power supply to the control module 10. The control unit 11, memory 12, and various circuit modules in the voltage detection circuit 15 of the control module 10 require a stable low-voltage DC power supply, typically 3.3V, 5V, or 12V. The control power supply module 9 obtains power from the mains power supply or the equipment's main power source, and after rectification, filtering, and voltage regulation, outputs a stable DC voltage to ensure the reliable operation of the control module 10.

[0045] The drive power supply module 13 provides operating power to the drive module 14. The drive module 14 needs to supply a large operating current to the laser chip, therefore requiring a high-power power supply. The drive power supply module 13 outputs the appropriate power supply voltage and current capability based on the rated current and voltage requirements of the laser chip. The design of separately powering the control power supply module 9 and the drive power supply module 13 avoids power interference to the control module 10 caused by the high current operation of the drive module 14, thus improving system stability.

[0046] Through the detailed design of this embodiment, the drive control system 1 achieves high-precision, fast-response voltage monitoring and protection functions. The voltage detection circuit 15, through multi-level signal processing, ensures the accuracy of the acquired voltage and its anti-interference capability. The intelligent judgment and rapid response of the control unit 11, combined with the rapid shutdown capability of the drive module 14, can cut off the laser output in a very short time when voltage abnormalities are caused by reflected light, effectively protecting the laser chip. The configuration of the human-machine interface module 8 gives the system good operability and flexibility, adapting to different application requirements.

[0047] This embodiment illustrates the startup initialization process of a semiconductor laser system and the method for configuring dynamic safety thresholds.

[0048] When the laser system is started, the system initialization steps are executed first. The control power supply module 9 and the drive power supply module 13 supply power to the control module 10 and the drive module 14 respectively. After each module is powered on, it enters the initialization state.

[0049] Control module 10 executes the calibration procedure. Control unit 11 sends a command to drive module 14 to adjust the drive current to a calibration current far below the laser chip's threshold current. The laser chip's threshold current refers to the critical current value at which the laser chip transitions from spontaneous emission to stimulated emission. Under the calibration current, the laser chip operates in the spontaneous emission region and does not emit laser light, but a measurable voltage signal exists across the chip's terminals. At this time, voltage detection circuit 15 can normally acquire the voltage signal.

[0050] Under calibration current, control unit 11 retrieves a preset reference voltage value from memory 12. The reference voltage value is a standard voltage value measured under the same calibration current conditions during laser chip factory testing or system integration testing, and is stored in memory 12. Control unit 11 compares the detected voltage currently acquired by voltage detection circuit 15 with the reference voltage and calculates the deviation between the two.

[0051] If the deviation between the detected voltage and the reference voltage is within the allowable range, for example, less than 5% or a certain absolute value, then the voltage detection circuit 15 is deemed to be working normally and has passed the self-test. The control unit 11 then gradually increases the drive current from the calibration current to the normal operating current of the laser chip, the laser chip begins to emit laser light, and the system enters the normal operating mode.

[0052] If the deviation between the detected voltage and the reference voltage exceeds the allowable range, it indicates a potential fault in the voltage detection circuit 15. This could be due to variations in the resistance value of the resistor divider network 16, a shift in the amplification factor of the operational amplifier circuit 18, or loss of calibration parameters in the analog-to-digital converter 19. In this case, the control unit 11 determines that the self-test has failed and immediately issues a fault alarm signal through the human-machine interface module 8, alerting the operator to a hardware fault in the system. Simultaneously, the control unit 11 halts the startup process, preventing the drive current from increasing to normal operating conditions, thus avoiding starting the laser under faulty detection circuit conditions and ensuring effective monitoring and protection.

[0053] After receiving a fault alarm, the operator needs to troubleshoot the hardware malfunction. Possible troubleshooting steps include checking the components of the voltage detection circuit 15 for proper function, secure connections, and stable power supply. After troubleshooting and repairing the hardware malfunction, the operator issues a re-self-test command through the human-machine interface module 8. The system then re-executes the initialization and self-test process until it passes the self-test before entering normal operating mode.

[0054] This initialization self-test mechanism ensures that the voltage detection circuit 15 is in normal working condition before the laser is started, avoiding missed alarms or false alarms caused by detection circuit failures, and improving the reliability and safety of the system.

[0055] Regarding dynamic safety threshold configuration, this embodiment sets multi-dimensional safety thresholds based on the voltage characteristics of the laser chip under different operating conditions. The operating voltage of the laser chip depends not only on the driving current but also on the ambient temperature. Under the same driving current, an increase in ambient temperature leads to changes in the band structure of the semiconductor material and a decrease in carrier mobility, thereby increasing the operating voltage.

[0056] During the system configuration phase, experimental tests were conducted under normal operating conditions without reflected light to measure the operating voltage of the laser chip at different operating currents and ambient temperatures, establishing a reference data table for the operating voltage. Based on this reference data, a safety threshold voltage was set for each combination of operating current and ambient temperature. The safety threshold voltage is typically set to the reference voltage plus a safety margin, such as 10% to 20% of the reference voltage, ensuring that the safety threshold covers the normal operating fluctuation range while maintaining sufficient sensitivity to abnormal voltage increases caused by reflected light.

[0057] These safety threshold parameters are stored in memory 12 in the form of a multidimensional data table. The table indexes are operating current and ambient temperature, and the corresponding values ​​are the safety threshold voltages under those conditions. During actual laser operation, the drive module 14 feeds back the current drive current value to the control unit 11. The temperature sensor (which can be located near the laser chip or at an appropriate location in the drive control system 1) measures the current ambient temperature and transmits it to the control unit 11. Based on the current operating current and ambient temperature, the control unit 11 searches for or interpolates the corresponding safety threshold voltage from memory 12 and uses this as the current judgment criterion.

[0058] This dynamic threshold configuration method takes into account the characteristics of laser chip operating voltage changing with operating conditions. By adjusting the safety threshold in real time, it avoids false triggering of protection due to normal voltage rise under high temperature or high current conditions, while ensuring accurate identification and timely protection of reflected light under various operating conditions. Compared with the scheme using a fixed safety threshold, dynamic threshold configuration significantly improves the adaptability and accuracy of the protection system.

[0059] This embodiment details the specific implementation of real-time monitoring of the laser chip's operating voltage, focusing on the principles for setting the sampling frequency and the signal processing method.

[0060] During normal operation of the laser chip, the voltage detection circuit 15 continuously collects the operating voltage across the laser chip at a preset sampling frequency. The sampling frequency is a key parameter affecting the system's response speed and protection effectiveness.

[0061] The sampling frequency setting needs to comprehensively consider the laser's operating characteristics and the return light response time. When the returned light enters the active region of the laser chip, the changes in carrier concentration and recombination process, and the resulting voltage rise, are not instantaneous but occur over a certain period. According to semiconductor physics principles, the establishment time of non-equilibrium carriers is related to the carrier recombination lifetime, typically on the order of nanoseconds to microseconds. Considering the cumulative effect of thermal effects, the voltage rise may reach a detectable level within several microseconds to tens of microseconds.

[0062] To capture voltage changes promptly, the sampling frequency should be much higher than the time scale of the voltage change. In this embodiment, the sampling frequency is set to 10 kHz to 100 kHz, i.e., the sampling period is 10 microseconds to 100 microseconds. Taking a sampling frequency of 50 kHz as an example, the voltage signal is acquired once every 20 microseconds, which can detect the change in a very short time after the voltage begins to rise due to the reflected light.

[0063] Under the control of the control unit 11, the analog-to-digital converter 19 continuously performs analog-to-digital conversion at a set sampling frequency, transmitting the digital voltage value obtained from each sample to the control unit 11. The control unit 11 maintains a sampling data buffer to store the most recent sample values, such as the most recent ten or twenty sample values.

[0064] The control unit 11 processes and judges each new sampled value. First, the control unit 11 compares the current sampled value with the pre-stored safety threshold voltage. If the current sampled value is less than or equal to the safety threshold voltage, the operating voltage is determined to be normal, the control unit 11 does not issue any control signal, the drive module 14 maintains the current current output, and the laser chip continues to work normally.

[0065] If the current sampled value is greater than the safety threshold voltage, the control unit 11 further checks whether the most recent consecutive sampled values ​​in the buffer all exceed the safety threshold. For example, the judgment condition can be set to three consecutive sampled values ​​exceeding the safety threshold. This continuous over-threshold judgment can effectively avoid false triggering caused by accidental voltage spikes or transient interference. Voltage spikes may be caused by factors such as switching transients of the drive current and electromagnetic interference, and their duration is very short, usually affecting only one or two sampling points. However, the voltage rise caused by reflected light is continuous and will exhibit over-threshold characteristics on multiple consecutive sampling points.

[0066] When the control unit 11 detects that multiple consecutive sampled values ​​exceed the safety threshold, it determines that there is a real backlight threat and triggers the protection mechanism. The control unit 11 immediately sends a shutdown signal to the drive module 14 through the output interface. The shutdown signal is a high-level or low-level digital signal, determined according to the control logic design of the drive module 14.

[0067] Upon receiving the shutdown signal, the internal control circuit of the drive module 14 immediately activates, shutting off the power switching device and cutting off the drive current output to the laser chip. The entire response time, from the shutdown signal issued by the control unit 11 to the complete cutoff of current output by the drive module 14, is typically in the range of several microseconds to tens of microseconds. Combined with the voltage detection sampling period, the total response time, from the onset of the reflected light to the laser chip and the completion of the system's protective action, can be controlled within hundreds of microseconds, effectively limiting the time the laser chip is exposed to dangerous reflected light and preventing continuous damage.

[0068] The filter circuit 17 plays a crucial role in the sampling and judgment process. Although the filter circuit 17 can filter out most high-frequency noise, it cannot completely eliminate all interference. The control unit 11 further improves the signal's anti-interference capability and ensures the accuracy of protection judgment by continuously performing multi-point threshold judgments and using selectable digital filtering algorithms (such as moving average filtering, median filtering, etc.).

[0069] In addition, the control unit 11 can record information such as the time of each protection trigger, operating current, and detection voltage, storing it in the memory 12 or uploading it to the host computer system via the communication interface for subsequent fault analysis and system optimization. Operators can analyze these records to understand the frequency and severity of backlighting, optimize processing parameters, or adjust safety threshold settings to further improve system performance.

[0070] This embodiment illustrates the specific process of restoring normal operation after the system triggers the protection mechanism and cuts off the drive current of the laser chip.

[0071] When the drive module 14 cuts off the drive current, the laser chip stops working, and the laser output is interrupted. At this time, the control unit 11 displays alarm information to the operator through the human-machine interface module 8, indicating that the system has detected reflected light and has executed a protection action. The alarm information may include detailed information such as the time the protection was triggered, the detected voltage value, and the current operating current, to help the operator understand the situation.

[0072] Upon receiving an alarm, operators need to investigate the cause of the reflected light. The generation of reflected light is usually related to processing parameters, workpiece characteristics, or optical path settings. Common causes include: the processing head being perpendicular or nearly perpendicular to the workpiece surface, causing reflected light to return along the original optical path; the workpiece surface having high reflectivity areas or specular reflective surfaces; improper focal point setting of the focusing lens, leading to changes in the light spot characteristics and stronger reflection; changes in the workpiece surface condition during processing, such as specular reflection from the molten pool surface; and poor optical path collimation or alignment, causing reflected light to more easily enter the transmission optical fiber.

[0073] To address the aforementioned possible causes, operators can take corresponding measures. For example, adjusting the angle of the processing head to ensure the laser illuminates the workpiece surface at a certain tilt angle, reducing backlighting; adjusting the focal position to change the spot characteristics; pre-treating the workpiece surface to reduce reflectivity; checking and adjusting the optical path collimation and alignment; and optimizing processing parameters, such as reducing power and adjusting the scanning speed, to reduce specular reflection from the molten pool.

[0074] After investigating and taking measures to eliminate the cause of the backlighting, the operator issues a command to resume operation through the human-machine interface module 8. Upon receiving the command, the control unit 11 initiates the recovery process.

[0075] The recovery process begins with testing. Control unit 11 instructs drive module 14 to resume supplying drive current to the laser chip, but the initial current is set to a low value, such as 20% to 50% of the normal operating current. At the lower current, the laser chip begins to operate, but with lower output power, thus posing a relatively small threat to the laser chip even if residual backlighting exists.

[0076] The control module 10 continuously monitors the operating voltage of the laser chip. The control unit 11 compares the detected operating voltage with the safe threshold voltage corresponding to the current operating current. If the operating voltage does not exceed the safe threshold at a lower current, it indicates that the backlighting problem may have been resolved or does not pose a threat at the current power.

[0077] The control unit 11 then gradually increases the drive current, for example, by 10% every few seconds, while continuously monitoring the operating voltage. At each current level, the control unit 11 compares the operating voltage with the corresponding safety threshold. If the operating voltage does not exceed the safety threshold during the gradual increase, it indicates that the backlighting problem has been effectively resolved, and the system can safely return to normal operation.

[0078] Once the drive current rises to the operating current before shutdown or the target operating current set by the operator, if the operating voltage still does not exceed the safety threshold, the control unit 11 determines that the recovery is successful, clears the alarm, and displays the information that the system has returned to normal operation via the human-machine interface module 8. The laser chip outputs laser stably under normal operating current, and processing operations can continue.

[0079] If the operating voltage exceeds the safety threshold again at any stage of the test, it indicates that the backlighting problem has not been effectively resolved. The control unit 11 will immediately trigger the protection mechanism again, sending a shutdown signal to the drive module 14 to cut off the drive current. At the same time, the control unit 11 will display the recovery failure information to the operator through the human-machine interface module 8, prompting that the backlighting problem needs to be investigated and resolved again.

[0080] Following the prompts, operators further analyze the cause of the problem and take more effective measures, such as adjusting the machining angle more significantly, changing the workpiece, and checking for any abnormalities in the optical path system. After troubleshooting and resolving the problem, the recovery process is executed again until normal operation is successfully restored.

[0081] This step-by-step testing recovery mechanism ensures that the laser chip is only restarted when it is confirmed to be safe, avoiding secondary damage caused by resuming operation before the problem is resolved. By gradually increasing the power from low to normal, even if reflected light reappears during testing, the damage to the laser chip is relatively limited due to the low power, further improving system safety.

[0082] In an extended implementation, the system may further include a gyroscope sensor. The gyroscope sensor is used to acquire the angle between the laser emitted from the semiconductor laser system and the normal direction of the workpiece, and transmits this angle information to the control module. The control module determines the risk level of backlighting at the current processing angle based on the angle information.

[0083] Specifically, the control module divides the angle range into different risk levels. For example, zero to ten degrees is defined as a high-risk zone, ten to twenty degrees as a medium-risk zone, and above twenty degrees as a low-risk zone. When the gyroscope sensor detects that the angle between the laser beam and the normal direction of the workpiece surface is in the high-risk zone, the control module issues a warning to the operator through the human-machine interface module.

[0084] During the process of restoring normal operation, the system displays the angle information when protection is triggered, assisting operators in quickly locating the cause of the problem. If the angle at the time of protection triggering is in the high-risk zone, the system prompts, "The reflected light may be caused by machining at a vertical angle; it is recommended to adjust the machining head angle or workpiece position." If the angle is in the low-risk zone, the system prompts, "The reflected light may be caused by other factors; it is recommended to check the optical path collimation, workpiece surface condition, etc." This intelligent cause analysis and prompting significantly reduces the difficulty of manual intervention and improves the accuracy and efficiency of problem troubleshooting. If the included angle at the time of protection triggering is in the high-risk zone, such as less than ten degrees, the control unit determines that the reflected light is likely caused by a vertical or near-vertical machining angle.

[0085] The system displays diagnostic information through the human-machine interface module, such as "Backlighting may be caused by machining at a vertical angle," and suggests the following measures with specific recommendations: "Adjust the machining head tilt angle to more than 20 degrees," "Rotate the workpiece to change the machining direction," and "Check the angle settings in the machining program." These suggestions directly point to the most likely cause of the problem, helping operators to quickly take targeted measures.

[0086] If the angle at which protection is triggered is in a low-risk zone, such as greater than 20 degrees, it indicates that a sufficiently strong reflected light was generated even at the tilt angle. This usually means that other factors are causing the reflected light. Control unit eleven provides different diagnostic prompts, such as "The current angle is relatively safe; the reflected light may be caused by other factors," suggesting checking the following aspects and listing the troubleshooting items: "Check if the transmission fiber end face is clean," "Check if the optical path collimation is normal," "Check the focusing lens focal point setting," "Check if there are specular reflection areas on the workpiece surface," and "Check the state of the molten pool during processing," etc. This situation-specific diagnostic prompt avoids blind troubleshooting and improves the efficiency of problem localization.

[0087] With the assistance of gyroscope sensors, the system enhances its intelligence level while maintaining a fixed safety threshold and ensuring protection reliability. This helps operators better understand the mechanism of backlight generation, optimize processing technology, reduce the frequency of backlight occurrence, and thus improve overall production efficiency and equipment reliability.

[0088] In an extended implementation including a gyroscope sensor, this invention achieves intelligent auxiliary diagnostics and early warning functions through angle monitoring. The gyroscope sensor acquires the angle between the laser beam and the normal direction of the workpiece surface in real time, and the control module determines the risk level of reflected light based on the angle. It is important to emphasize that the safety threshold remains a fixed value, determined by the performance characteristics of the laser chip, ensuring the reliability and consistency of the protection function. The value of the gyroscope sensor lies in providing auxiliary information, not in altering the protection logic.

[0089] When a high-risk angle is detected, the system issues a warning to the operator through the human-machine interface module, guiding the operator to proactively adjust the processing angle and reduce the probability of backlighting from the source. This warning mechanism does not forcibly interrupt processing but provides suggestive guidance, balancing safety and production continuity. When the system triggers the protection mechanism, the control module automatically records detailed parameters such as angle, voltage, and current at the trigger moment, providing data support for subsequent analysis. Operators can review historical records to summarize the patterns of backlighting, identify high-risk operating conditions, and develop targeted process optimization measures.

[0090] During the troubleshooting phase, the system provides intelligent cause analysis prompts based on the angle information at the time of protection triggering, helping operators quickly pinpoint the root cause of the problem. If the problem occurs at a high-risk angle, the system suggests adjusting the machining angle; if it occurs at a low-risk angle, the system suggests checking other factors such as optical path collimation and workpiece surface condition. This intelligent diagnostic function significantly reduces the difficulty of manual intervention, decreases reliance on operator experience, and improves the accuracy and efficiency of problem troubleshooting.

[0091] Through a combination of angle monitoring, risk warning, data recording, and intelligent diagnostics, the system helps operators better understand the mechanism of reflected light generation, optimize processing parameters, reduce the frequency of reflected light occurrence, and decrease the number of protection triggers, thereby improving equipment utilization and production efficiency, while ensuring the reliability of protection functions. This intelligent design reflects the system's human-centered approach and provides a more complete and user-friendly solution for industrial laser processing.

[0092] like Figure 3 As shown, Figure 3 This is a schematic flowchart illustrating a method for backlight protection provided in an embodiment of this application. This method is applied to laser systems during laser processing of workpieces, achieving effective protection of the laser chip through real-time monitoring and a rapid response mechanism.

[0093] Under normal operating conditions, the laser chip emits a laser beam, which is transmitted through an optical fiber and the processing head to the workpiece surface for machining. During the machining process, the system continuously executes the following protective procedures: Step S100: Real-time monitoring of the laser chip's operating voltage. The control module continuously acquires the operating voltage signal across the laser chip via a voltage detection circuit. The voltage detection circuit acquires the signal at a preset sampling frequency, and after signal conditioning and analog-to-digital conversion, transmits the digitized voltage data to the control unit. The control unit continuously receives the voltage data, establishing a real-time monitoring mechanism to ensure that any abnormal voltage changes are detected promptly.

[0094] Step S200: Compare the monitored operating voltage with a preset safety threshold. The control unit retrieves the preset safety threshold parameter from the memory and compares the real-time collected operating voltage value with the safety threshold. The safety threshold is determined based on factors such as the characteristics of the laser chip, the current operating current, and the ambient temperature, representing the upper limit of the voltage during normal operation of the laser chip. Through continuous comparison, the control unit can identify whether the operating voltage is within the safe range.

[0095] Step S300: When the monitored operating voltage exceeds the preset safety threshold, a shutdown signal is sent to the drive module to cut off the drive current output to the laser chip. Once the control unit determines that the operating voltage exceeds the safety threshold, it immediately determines that there is a backlight threat and triggers the protection mechanism. The control unit sends a shutdown command to the drive module through the control interface. After receiving the command, the drive module quickly shuts down the internal power switching device, cutting off the current supply to the laser chip. The laser chip stops working, and the laser output is interrupted, thereby blocking the generation and propagation path of the backlight and preventing continuous backlight from causing further damage to the laser chip.

[0096] Through the cyclical execution of the three basic steps described above, the system achieves continuous monitoring and rapid protection against reflected light. This method is based on the physical mechanism by which reflected light causes abnormal voltage increases in the laser chip. It identifies reflected light by directly monitoring changes in electrical parameters, eliminating the need for external optical devices or photodetectors. This approach offers advantages such as fast response speed, low cost, and high reliability. The entire protection process, from detecting the voltage anomaly to cutting off the current, has a response time controllable to the microsecond to millisecond level. This allows for protective actions to be completed before reflected light causes serious damage, effectively ensuring the safe operation of the laser chip.

[0097] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0098] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0099] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0100] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0101] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0102] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above.

[0103] The implementation of all or part of the processes in the methods of the above embodiments can also be accomplished by a computer program product. When the computer program product is run on a terminal device, the terminal device can implement the steps in the various method embodiments described above.

[0104] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A semiconductor laser system, characterized by, include: Laser, including laser chip and shaping lens assembly; Transmission fiber; Processing head; as well as The drive control system includes a drive module and a control module. in, The laser emitted by the laser chip is shaped by the shaping mirror group and then coupled into the transmission optical fiber, from which the laser beam is output to the processing head for emission. The driving module provides operating current to the laser chip; The control module monitors the operating voltage of the laser chip in real time. When the monitored operating voltage exceeds the preset safety threshold, it sends a shutdown signal to the drive module. After receiving the shutdown signal, the drive module cuts off the drive current output to the laser chip.

2. The semiconductor laser system of claim 1, wherein, The control module includes a control unit, a memory, and a voltage detection circuit, wherein the memory pre-stores the safety threshold. The voltage detection circuit acquires the operating voltage across the laser chip and transmits it to the control unit; The control unit compares the collected operating voltage with the safety threshold.

3. The semiconductor laser system according to claim 2, characterized in that, The drive control system also includes a human-machine interaction module. In response to the user's input of the safety threshold on the human-machine interaction module, the control unit stores the input safety threshold in a memory.

4. The semiconductor laser system of claim 2, wherein, It also includes a gyroscope sensor, which collects the angle between the laser emitted by the semiconductor laser system and the normal direction of the workpiece, and transmits it to the control module. The control module determines the risk level of backlight at the current processing angle based on the angle, and issues a warning through the human-machine interaction module when a high-risk angle is detected.

5. The semiconductor laser system according to any one of claims 1 to 4, characterized in that The drive control system further includes a control power supply module and a drive power supply module. The control power supply module supplies power to the control module, and the drive power supply module supplies power to the drive module.

6. A method for retroreflective light protection, characterized in that, Includes the following steps: When processing a workpiece using the laser emitted from the semiconductor laser system according to any one of claims 1 to 5, the operating voltage of the laser chip is monitored in real time. The monitored operating voltage is compared with the preset safety threshold. When the detected operating voltage exceeds the preset safety threshold, a shutdown signal is sent to the drive module to cut off the drive current output to the laser chip.

7. The return light protection method according to claim 6, wherein Before the real-time monitoring of the laser chip's operating voltage, a system initialization step is also included: Adjust the drive current to a calibration current below the laser threshold current; The preset reference voltage is retrieved, and the detected voltage is compared with the reference voltage to determine whether the voltage detection circuit is working properly. If the deviation between the detected voltage and the reference voltage is within the allowable range, the self-test is deemed qualified and the system enters normal operating mode. If the deviation exceeds the allowable range, a fault alarm signal will be issued and the startup process will be stopped. The self-test will be re-executed after the hardware fault is investigated.

8. The return light protection method according to claim 6, wherein The preset safety threshold is set according to the operating voltage value of the laser under different operating currents and different ambient temperatures. During the actual operation of the laser, the corresponding safety threshold voltage is retrieved according to the current operating current and ambient temperature.

9. The return light protection method according to claim 6, wherein The real-time monitoring of the laser chip's operating voltage includes: The operating voltage across the laser chip is continuously collected according to a preset sampling frequency, wherein the sampling frequency is determined based on the laser's operating characteristics and the return light response time.

10. The return light protection method according to claim 6, wherein After cutting off the drive current output to the laser chip, the process also includes a step to restore normal operation: Investigate and eliminate the causes of the reflected light; The relationship between the operating voltage of the test laser chip and the safety threshold was compared. If the operating voltage does not exceed the safety threshold, the alarm state will be deactivated and the drive current output will be restored. If the operating voltage continues to exceed the safety threshold, re-investigate and resolve the problem.

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