Laser protection circuit

Abstract

The invention provides a laser protection circuit, and relates to the technical field of laser driving and safety protection. The protection circuit is arranged between a laser driver and a laser, and comprises a first interface connected with the laser driver; the first interface is provided with a first pin; the second interface is connected with the laser; the second interface is provided with a second pin; the relay array module comprises a double-pole double-throw relay with a common contact, a normally open contact and a normally closed contact; wherein the common contact is connected to the second pin; the normally open contact is connected to the first pin; the normally closed contact is connected to a grounding point; when the relay array module is in a power-off state, the common contact and the normally-closed contact are conducted, and the second pin is connected to the grounding point.

Description

Technical Field

[0001] This invention relates to the field of laser driving and safety protection technology, and in particular to a laser protection circuit. Background Technology

[0002] With the widespread application of laser technology in industry, communications, and medicine, the stability and safety of lasers have become increasingly important. As a high-precision, high-power optoelectronic device, the normal operation of a laser is highly susceptible to factors such as power fluctuations, signal interference, overcurrent, overvoltage, and static electricity. Once a laser encounters these abnormal conditions, the optical or semiconductor materials inside the laser may suffer irreversible damage, leading to equipment failure and even safety risks.

[0003] Currently, common laser protection methods mainly include fuses, current-limiting circuits, or physical switches. While these methods can suppress overcurrent or short-circuit problems to some extent, they mostly rely on simple electrical components and cannot effectively handle high-frequency noise, electrostatic discharge, or more complex signal interference problems. In addition, most protection designs have limited functionality and are difficult to adapt to the system-level protection needs of complex industrial environments. Summary of the Invention

[0004] In view of the above problems, the present invention provides a laser protection circuit that can effectively prevent the laser from being affected by circuit faults or abnormal currents, thereby improving the safety and long-term reliability of the laser system.

[0005] This invention provides a laser protection circuit, disposed between a laser driver and a laser. The protection circuit includes: a first interface connected to the laser driver; the first interface having a first pin; a second interface connected to the laser; the second interface having a second pin; and a relay array module, including a double-pole double-throw relay having a common contact, a normally open contact, and a normally closed contact; wherein the common contact is connected to the second pin; the normally open contact is connected to the first pin; and the normally closed contact is connected to a ground point; wherein, when the relay array module is in a de-energized state, the common contact and the normally closed contact are connected, and the second pin is connected to the ground point.

[0006] According to an embodiment of the present invention, the protection circuit further includes: when the relay array module is energized, the common contact and the normally open contact are connected to connect the first pin and the second pin.

[0007] According to an embodiment of the present invention, the first interface has a plurality of first pins, and the second interface has a plurality of second pins; the relay array module includes a plurality of double-pole double-throw relays; wherein, the common contact of each double-pole double-throw relay is connected to a corresponding second pin of the second interface; the normally open contact is connected to a corresponding first pin of the first interface; and the normally closed contacts are all connected to a ground point; the relay array module synchronously controls the one-to-one correspondence between the plurality of first pins and the plurality of second pins.

[0008] According to an embodiment of the present invention, the potential of the grounding point is the laser power supply ground potential or the system chassis protective ground potential.

[0009] According to an embodiment of the present invention, the protection circuit further includes an optocoupler and relay control module; the optocoupler and relay control module includes an optocoupler isolation unit and a drive unit; wherein, the input terminal of the optocoupler isolation unit receives external control signals, and the output terminal is coupled to the drive unit; the optocoupler isolation unit is used to electrically isolate the transmission of external control signals; the output terminal of the drive unit is connected to the relay array module.

[0010] According to an embodiment of the present invention, the protection circuit further includes a power supply; wherein the power supply provides operating voltage to the relay array module and the optocoupler and relay control module; the optocoupler and relay control module controls the switching of current between the power supply and the relay array module according to an external control signal.

[0011] According to an embodiment of the present invention, in the event of a power failure, the relay array module is in a de-energized state; in the event of a normal power supply, the relay array module is in a energized state.

[0012] According to an embodiment of the present invention, the driving unit includes a driving transistor; the base of the driving transistor is connected to the output terminal of the optocoupler isolation unit; the emitter and collector of the driving transistor are connected in series in the power supply circuit of the power supply and relay array module.

[0013] According to an embodiment of the present invention, when the external control signal is valid, the driving transistor is turned on, so that the relay array module is in a powered state; when the external control signal is invalid, the driving transistor is turned off, so that the relay array module is in a de-powered state.

[0014] According to an embodiment of the present invention, the external control signal includes either a laser enable signal or a safety interlock signal.

[0015] According to an embodiment of the present invention, the circuit further includes a status indication unit; the status indication unit is connected in parallel with the relay array module; wherein the status indication unit includes a light-emitting diode; the light-emitting diode is lit when the relay array module is in a powered state; and the light-emitting diode is turned off when the relay array module is in a de-powered state.

[0016] Compared with the prior art, the laser protection circuit provided by the present invention has at least the following beneficial effects:

[0017] (1) Through the collaborative design of optocoupler and relay control module and relay array module, the electrical connection between laser and laser driver can be quickly cut off when an abnormality occurs, so as to achieve complete physical isolation; at the same time, the normally closed contact of double-pole double-throw relay is used to connect the second pin to the ground point to form a reliable electrostatic discharge path, which fundamentally prevents electrostatic accumulation and transient voltage damage.

[0018] (2) By integrating the first interface, relay array module, second interface, power supply and optocoupler and relay control module on the same printed circuit board, it can be directly connected between the laser driver and the laser without changing the original cable or equipment structure, which improves its deployment convenience and system compatibility.

[0019] (3) The working state of the laser can be quickly switched by changing the external control signal, which ensures the integrity of the external control signal and achieves multiple protections for the laser with long-term reliability. Attached Figure Description

[0020] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0021] Figure 1 A schematic diagram of a laser protection circuit according to an embodiment of the present invention is shown.

[0022] Figure 2 A schematic diagram illustrating the operation of a laser protection circuit according to an embodiment of the present invention is shown.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-First interface; 2-Relay array module; 3-Second interface; 4-Power supply; 5-Optical coupler and relay control module. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0027] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0028] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of the present invention. Throughout the accompanying drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding the present invention.

[0029] Figure 1 A schematic diagram of a laser protection circuit according to an embodiment of the present invention is shown.

[0030] like Figure 1 As shown, in this embodiment of the invention, a laser protection circuit is disposed between the laser driver and the laser. The laser protection circuit includes: a first interface 1, a second interface 3, and a relay array module 2. The first interface 1 is connected to the laser driver and has a first pin; the second interface 3 is connected to the laser and has a second pin; the relay array module 2 includes a double-pole double-throw relay with a common contact, a normally open contact, and a normally closed contact; wherein, its common contact is connected to the second pin; its normally open contact is connected to the first pin; and its normally closed contact is connected to the ground point.

[0031] For example, the first interface 1 can be a connector that matches the output port of the connected laser driver, such as DB9 (9-pin D-type data interface connector), DB15 (9-pin D-type data interface connector), or other types of multi-pin aviation connectors. Similarly, the second interface 3 can be a connector that matches the input port of the connected laser itself.

[0032] When relay array module 2 is de-energized, the common contact of the double-pole double-throw relay is connected to its normally closed contact. The second pin on the second interface connecting to the laser is connected to the ground point through the normally closed contact. This provides the laser with a stable, low-impedance electrostatic discharge path, effectively preventing electrostatic discharge (ESD) damage caused by charge accumulation due to the second pin being left floating. Simultaneously, the common contact of the double-pole double-throw relay is physically disconnected from its normally open contact. This means that all electrical paths between the first interface 1 and the second interface 3 are completely and physically isolated. No signal or power from the laser driver can reach the laser, thus providing absolutely safe isolation during system power-on initialization, fault conditions, or shutdown. For example, the ground point potential can be the laser power ground potential or the system chassis protective ground potential, used to provide a low-impedance, stable discharge path for the laser port when the double-pole double-throw relay is released.

[0033] When the relay array module 2 is energized, the common contact of the double-pole double-throw relay is connected to its normally open contact, so that the first pin on the first interface and the second pin on the second interface are reliably connected, that is, a complete electrical connection is established between the first interface and the second interface, and the laser driver can drive and control the laser normally. At the same time, the common contact of the double-pole double-throw relay is disconnected from its normally closed contact, cutting off the short circuit between the second pin and the ground point, so that the laser is removed from the protective grounding state and enters the normal working mode.

[0034] In some embodiments, the first interface 1 has multiple first pins for connecting various output terminals of the laser driver, such as main drive current and modulation signals; correspondingly, the second interface 3 has multiple second pins for connecting various functional input terminals of the laser, such as positive and negative drive terminals, photoelectric monitoring terminals, and temperature detection terminals. Multiple signal channels are provided between the first and second interfaces. To achieve independent and synchronous control of these signal channels, the relay array module 2 consists of multiple double-pole double-throw relays, the number of which is the same as the number of signal channels to be controlled. Each double-pole double-throw relay independently manages one signal channel. Specifically, the common contact of each double-pole double-throw relay is connected to a specific second pin of the second interface, and its normally open contact is connected to the corresponding first pin in the first interface; while the normally closed contacts of all double-pole double-throw relays are connected to the ground point.

[0035] For example, when the relay array module 2 is energized, the common contacts of all double-pole double-throw relays are synchronously connected to their normally open contacts. At this time, all preset signal channels between the first interface and the second interface are established and connected, and the system can immediately start normal operation, avoiding logic errors or instantaneous impacts that may be caused by asynchronous conduction of each signal channel. When the relay array module 2 is de-energized, the common contacts of all double-pole double-throw relays are synchronously connected to their normally closed contacts in a spring state. At this time, the connection between all first pins and second pins is simultaneously and completely physically cut off, and all second pins on the second interface are simultaneously shorted to the ground point.

[0036] By employing a relay array module 2 containing multiple double-pole double-throw relays and its synchronous drive control, systematic protection of the laser's critical electrical interfaces is achieved. Whether it is the orderly connection during startup or the emergency shutdown in case of a fault, it is carried out in a holistic and synchronous manner, which improves the reliability and safety of the laser during operation and can effectively prevent equipment risks that may be caused by residual connections or grounding delays in a single signal channel.

[0037] In some embodiments, to achieve safe, reliable and interference-resistant intelligent control of the relay array module 2, the laser protection circuit further includes an optocoupler and relay control module 5; the optocoupler and relay control module 5 includes an optocoupler isolation unit and a drive unit.

[0038] The input terminal of the optocoupler isolation unit forms the control side, used to receive external control signals, such as laser enable signals or safety interlock signals from the laser driver or upper control system; its output terminal forms the power side and is coupled to the drive unit through an optoelectronic conversion device; wherein, the input terminal of the optocoupler isolation unit and the source circuit (such as the laser driver) of the external control signal are referenced to the same ground potential to form an effective signal loop. The optocoupler isolation unit is used to form electrical isolation between the input path of the external control signal and the drive unit, so that the external control signal can be transmitted in an electrically isolated manner; the output terminal of the drive unit is connected to the relay array module 2.

[0039] In some embodiments, the optocoupler isolation unit includes an optocoupler light-emitting diode (LED) and an optocoupler transistor (PTZ). When a valid high-level signal is received at the input terminal of the optocoupler isolation unit (i.e., the anode and cathode of the LED inside), the LED conducts and emits light, which illuminates the PTG, causing it to switch from a cutoff state to a conducting state. This process establishes an optically coupled link between the control side and the power side, enabling lossless transmission of external control signals and complete electrical isolation between the control side and the power side. The optocoupler isolation unit effectively blocks electrical noise and ground potential difference from the control side from propagating to the laser side, protecting the laser from interference and meeting the insulation requirements for electrical isolation in safety regulations.

[0040] In some embodiments, the laser protection circuit further includes a power supply 4, which provides operating voltage to the relay array module 2 and the optocoupler and relay control module 5. The optocoupler and relay control module 5 controls the flow of current between the power supply 4 and the relay array module 2 based on an external control signal (such as an enable signal), i.e., whether to supply power to the relay array module 2. Specifically, when the external control signal is valid, the optocoupler and relay control module 5 is turned on, establishing a complete current path from the power supply 4 to the relay array module 2, thus energizing the relay array module 2. When the external control signal is invalid or the optocoupler and relay control module 5 itself malfunctions, the optocoupler and relay control module 5 cuts off this current path, de-energizing the relay array module 2 and activating the aforementioned protective grounding state.

[0041] Preferably, power supply 4 is a DC regulated power supply module with a rated output voltage of 5V, which can be connected to an external power adapter via a standard socket or terminal block. To ensure stable and safe operation in complex industrial power environments, power supply 4 integrates filtering circuits, overvoltage / undervoltage protection circuits, and reverse polarity protection circuits in its input and output circuits.

[0042] For example, when power supply 4 is abnormal, relay array module 2 is in a de-energized state; when power supply 4 is normal, relay array module 2 is in a energized state.

[0043] In some embodiments, the driving unit includes a driving transistor, the base of which is connected to the output of the optocoupler isolation unit, and the emitter and collector of the driving transistor are connected in series in the power supply circuit of the power supply 4 and the relay array module 2.

[0044] For example, the driving transistor can be a PNP transistor, with its base connected to the output of the optocoupler isolation unit through a resistor, its emitter connected to the positive terminal of the power supply 4, and its collector connected to the common connection terminal of the coils of all double-pole double-throw relays in the relay array module 2. That is, the ends of the coils of each double-pole double-throw relay with the same polarity are all electrically connected together (i.e., the common connection terminal of the coils), while the other end is uniformly connected to the system ground.

[0045] Specifically, when the optocoupler isolation unit receives a valid external control signal and turns on, its output terminal pulls the base potential of the PNP transistor down to near ground potential, and the PNP transistor turns on; at this time, the current provided by the power supply 4 flows synchronously through all double-pole double-throw relays, so that the entire relay array module 2 is synchronously energized and engaged, making the laser in a working connected state.

[0046] Specifically, when the external control signal is invalid, the input terminal of the optocoupler isolation unit is faulty, or the device itself of the optocoupler isolation unit is damaged, the output terminal of the optocoupler isolation unit is cut off. At this time, the base potential of the PNP transistor is rapidly pulled up to a voltage close to that of power supply 4, causing the PNP transistor to immediately cut off, completely cutting off the current flowing to the common connection terminal of the coil. In other words, regardless of whether power supply 4 itself is normal, the relay array module 2 will be in a de-energized release state due to the current being cut off, thereby forcing it into a physically disconnected and grounded safety protection state.

[0047] In some embodiments, the laser protection circuit further includes a status indicator unit; the status indicator unit is connected in parallel with the relay array module 2; wherein the status indicator unit includes a light-emitting diode (LED). For example, the LED is lit when the relay array module 2 is energized; the LED is off when the relay array module 2 is de-energized. The LED indicates whether the laser and laser driver are currently connected, facilitating the operator's observation of the system status.

[0048] In some embodiments, the operation of the laser protection circuit may include an initial and protection state, a normal operation state, a fault protection state, and a state recovery state.

[0049] For example, in the initial protection state, when the laser protection circuit is not powered on, or does not receive a valid external control signal after power-on, the drive unit in the optocoupler and relay control module 5 remains off, and the coils of all double-pole double-throw relays in the relay array module 2 are de-energized, meaning the relay array module 2 is in a de-energized state. At this time, the common contact of each double-pole double-throw relay is disconnected from its normally open contact, physically isolating all signal channels between the first interface 1 and the second interface 3; simultaneously, the common contact of each double-pole double-throw relay is connected to its normally closed contact, short-circuiting all the second pins on the second interface 3 and connecting them to the ground point. In this state, the laser and the drive unit are completely isolated, and the grounding of the second pins forms an electrostatic discharge path, achieving protection upon power-on.

[0050] For example, under normal operating conditions, when the external control signal becomes active (e.g., high level) and power supply 4 is normal, the optocoupler isolation unit is turned on, which in turn drives its drive unit to turn on, supplying power to the relay array module 2. All double-pole double-throw relays simultaneously engage, and their common contact switches to conduct with the normally open contact, thereby reliably connecting the first interface 1 and the second interface 3 according to the predetermined wiring sequence. At this time, the laser enters the normal operating mode. The LED in the status indicator unit lights up, indicating that the laser has entered the normal operating mode.

[0051] For example, in fault protection mode, if the external control signal becomes invalid (such as low level) or the power supply 4 malfunctions during laser operation, the optocoupler and relay control module 5 will immediately cut off the power supply to the relay array module 2. The coil of the double-pole double-throw relay will quickly lose magnetism, and all contacts will be released immediately under the action of the spring. The state of the laser protection circuit will instantly switch from the normal working state back to the initial protection state, thereby achieving rapid fault response and safety isolation.

[0052] For example, once the fault is cleared and the external control signal is restored to its effective state, the laser protection circuit automatically returns to normal operation from the fault protection state, completing the state recovery.

[0053] In some embodiments, the first interface 1, the relay array module 2, the second interface 3, the power supply 4, and the optocoupler and relay control module 5 can be integrated on the same printed circuit board to form a plug-in adapter board that can be directly connected between the laser driver and the laser.

[0054] Figure 2 A schematic diagram illustrating the operation of a laser protection circuit according to an embodiment of the present invention is shown.

[0055] like Figure 2 As shown, in this embodiment of the invention, the working process of the laser protection circuit mainly includes steps S210 to S230:

[0056] In step S210, the laser protection circuit is in the initial protection state, wherein the optocoupler control drive transistor is kept off, the common contact and normally open contact of each double-pole double-throw relay in the relay array module 2 are in the open state, and all signal channels between the first interface 1 and the second interface 3 are physically isolated; the common contact and normally closed contact are connected, the second pin is short-circuited and connected to the ground point, forming an electrostatic discharge path to prevent the laser from being damaged by the second pin being suspended and charged and by electrostatic discharge;

[0057] In step S220, when the external control signal is active at a high level, the optocoupler transistor is turned on and transmits the external control signal to the driving transistor, thereby energizing the relay array module 2.

[0058] In step S230, all double-pole double-throw relays in relay array module 2 are energized, their common contact and normally open contact are connected, and the first interface 1 and the second interface 3 are connected, so that the laser starts to work normally.

[0059] Step S221 may also be included after step S220.

[0060] In step S221, when the external control signal becomes low-level and invalid, the optocoupler transistor is cut off and transmits the external control signal to the driver transistor, thereby causing the relay array module 2 to be in a de-energized state. Its common contact is disconnected from the normally open contact and switches back to the normally closed contact, triggering the initial protection state. When the external control signal returns to a high-level and valid state, step S230 continues.

[0061] In summary, the laser protection circuit provided by this invention, through the collaborative design of the optocoupler and relay control module and the relay array module, can quickly disconnect the electrical connection between the laser and the laser driver in the event of an anomaly, achieving complete physical isolation. Simultaneously, by utilizing the normally closed contact of a double-pole double-throw relay to connect the second pin to the grounding point, a reliable electrostatic discharge path is formed, fundamentally preventing electrostatic accumulation and transient voltage damage. By integrating the first interface, relay array module, second interface, power supply, and optocoupler and relay control module onto the same printed circuit board, it can be directly connected in series between the laser driver and the laser without altering the original cabling or equipment structure, improving deployment convenience and system compatibility. The laser's operating state can be quickly switched by changes in external control signals, ensuring the integrity of external control signals while achieving long-term reliable multi-layered protection for the laser.

[0062] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser protection circuit, disposed between a laser driver and a laser, characterized in that, The protection circuit includes: A first interface (1) is connected to the laser driver; the first interface is provided with a first pin; The second interface (3) is connected to the laser; the second interface is provided with a second pin; The relay array module (2) includes a double-pole double-throw relay having a common contact, a normally open contact, and a normally closed contact; wherein, the common contact is connected to the second pin; the normally open contact is connected to the first pin; and the normally closed contact is connected to the ground point. When the relay array module (2) is in a de-energized state, the common contact is connected to the normally closed contact, and the second pin is connected to the grounding point.

2. The laser protection circuit according to claim 1, characterized in that, The protection circuit also includes: When the relay array module (2) is energized, the common contact is connected to the normally open contact to connect the first pin and the second pin.

3. The laser protection circuit according to claim 1, characterized in that, The first interface (1) has multiple first pins, and the second interface (3) has multiple second pins; the relay array module (2) includes multiple double-pole double-throw relays; In this configuration, the common contact of each of the double-pole double-throw relays is connected to a corresponding second pin of the second interface; the normally open contact is connected to a corresponding first pin of the first interface; and the normally closed contacts are all connected to the ground point. The relay array module (2) synchronously controls the one-to-one correspondence between multiple first pins and multiple second pins.

4. The laser protection circuit according to claim 1, characterized in that, The potential of the grounding point is the laser power supply ground potential or the system chassis protective ground potential.

5. The laser protection circuit according to claim 1, characterized in that, The protection circuit also includes an optocoupler and relay control module (5). The optocoupler and relay control module (5) includes an optocoupler isolation unit and a drive unit; The input terminal of the optocoupler isolation unit receives external control signals, and the output terminal is coupled to the driving unit; the optocoupler isolation unit is used to electrically isolate the transmission of the external control signals. The output terminal of the drive unit is connected to the relay array module (2).

6. The laser protection circuit according to claim 5, characterized in that, The protection circuit also includes a power supply (4). The power supply (4) provides operating voltage for the relay array module (2) and the optocoupler and relay control module (5); The optocoupler and relay control module (5) controls the switching of current between the power supply (4) and the relay array module (2) according to the external control signal.

7. The laser protection circuit according to claim 6, characterized in that, When the power supply (4) is abnormal, the relay array module (2) is in a de-energized state; when the power supply (4) is normal, the relay array module (2) is in a energized state.

8. The laser protection circuit according to claim 6, characterized in that, The driving unit includes a driving transistor; The base of the driving transistor is connected to the output terminal of the optocoupler isolation unit; The emitter and collector of the driving transistor are connected in series in the power supply circuit of the power supply (4) and the relay array module (2).

9. The laser protection circuit according to claim 8, characterized in that, When the external control signal is valid, the driving transistor is turned on, so that the relay array module (2) is in a powered state; When the external control signal is invalid, the driving transistor is cut off, causing the relay array module (2) to be in a de-energized state.

10. The laser protection circuit according to claim 5, characterized in that, The external control signal includes either the laser enable signal or the safety interlock signal.

11. The laser protection circuit according to claim 1, characterized in that, The circuit also includes a status indication unit; the status indication unit is connected in parallel with the relay array module (2); The status indication unit includes a light-emitting diode; When the relay array module (2) is energized, the light-emitting diode is lit; when the relay array module (2) is de-energized, the light-emitting diode is turned off.

Images