Laser thermal stabilization maintenance method, laser power supply system, and laser

Abstract

The application relates to a laser thermal stability maintaining method, a laser power supply system and a laser. The method comprises the following steps: acquiring a current light-emitting frequency of a light-emitting pulse signal of a laser; in response to the current light-emitting frequency being less than a preset frequency threshold, generating a preheating pulse train signal before the light-emitting pulse signal is generated; wherein the total power generated by the laser under the driving of the preheating pulse train signal and the light-emitting pulse signal is maintained within a preset thermal stability power interval. The method can overcome the thermal lens effect of the laser crystal and improve the thermal stability of the laser.

Description

Technical Field

[0001] This application relates to the field of laser technology, and in particular to a method for maintaining the thermal stability of a laser, a laser power supply system, and a laser. Background Technology

[0002] Lasers, as a novel light source, have wide applications in various fields. There are many types of lasers; for example, Nd:YAG lasers, which use xenon lamps as pump sources, hold a significant share of the laser market. The thermal stability of the crystal is a crucial indicator for solid-state lasers, significantly impacting output power, beam quality, and overall stability.

[0003] In traditional technology, the principle of xenon lamp-pumped solid-state laser generation is as follows: the power control circuit generates a pulse drive signal to drive the IGBT switch in the discharge circuit, applying a pulsed current to the xenon lamp to emit pulsed light, which then illuminates the laser crystal to produce laser light. However, solid-state lasers have very low efficiency. Only a small portion of the total energy input to the pump lamp is converted into laser output; the vast majority of the pump energy is converted into heat loss in the lamp. A large portion of the electrical energy consumed in laser generation is converted into heat energy. Furthermore, due to variations in the required output frequency and pulse width (i.e., different power and heat outputs), the laser crystal deforms differently, leading to a thermal penetration effect. This thermal penetration effect affects the spot size and beam quality, and is particularly detrimental to the effectiveness of laser therapy in the medical field. Summary of the Invention

[0004] Therefore, it is necessary to provide a laser thermal stability maintenance method, a laser power supply system, and a laser that can improve the thermal transmission stability of the laser crystal, in order to address the above-mentioned technical problems.

[0005] In a first aspect, a method for maintaining the thermal stability of a laser is provided, the method comprising:

[0006] Obtain the current emission frequency of the laser's emission pulse signal;

[0007] In response to the current emission frequency being less than a preset frequency threshold, a preheating pulse train signal is generated before the emission pulse signal is generated; wherein, driven by the preheating pulse train signal and the emission pulse signal, the total power generated by the laser is maintained within a preset thermally stable power range.

[0008] In some embodiments, the method further includes: determining whether the current total power of the laser is lower than the lower limit of a preset thermally stable power range; if so, proceeding to the step of generating a preheating pulse train signal before generating the emission pulse signal; if not, stopping the generation of the preheating pulse train signal.

[0009] In some embodiments, generating a preheating pulse train signal includes: generating a plurality of sub-pulses using a drive control device; and forming a pulse group with the plurality of sub-pulses, forming a pulse cluster with the plurality of pulse groups, and forming a preheating pulse train signal with at least one pulse cluster.

[0010] In some embodiments, the interval between sub-pulses in each pulse group is a first interval, the interval between pulse groups in each pulse cluster is a second interval, and the interval between pulse clusters is a third interval; wherein the first interval is smaller than the second interval, and the second interval is smaller than the third interval.

[0011] In some embodiments, the frequency of the sub-pulse is greater than the frequency of the pulse group, and the frequency of the pulse group is greater than the frequency of the pulse cluster.

[0012] In some embodiments, the drive control device includes a microcontroller, which generates multiple sub-pulses by: obtaining the period information of the drive pulse by configuring the frequency division information and reload information of the timer of the drive control device; and obtaining the sub-pulses by controlling the number, frequency and duty cycle of the drive pulses; wherein the drive power of the sub-pulses is less than the light output threshold of the laser.

[0013] In some embodiments, the method further includes: inserting n driving pulses with zero duty cycle between each pulse group to separate each pulse group, and inserting m driving pulses with zero duty cycle between each pulse group to separate each pulse cluster; wherein n and m are positive integers, and m is greater than n.

[0014] In some embodiments, the method further includes: inserting a re-preheating pulse train signal between the preheating pulse train signal preceding the light-emitting pulse signal and the light-emitting pulse signal; wherein the interval between the re-preheating pulse train signal and the light-emitting pulse signal is smaller than the interval between the re-preheating pulse train signal and the preheating pulse train signal.

[0015] Secondly, a laser power supply system is provided, comprising a charging circuit, an energy storage capacitor network, a high-voltage triggering circuit, a drive control device, a pre-burning sustaining circuit, and a pump source; wherein the pre-burning sustaining circuit includes an insulated-gate bipolar transistor element; wherein...

[0016] A charging circuit is used to charge the energy storage capacitor network.

[0017] A high-voltage trigger circuit is used to output a trigger voltage to the pump source to ionize the inert gas inside the pump source.

[0018] An energy storage capacitor network is used to discharge to a pump source according to a light pulse signal; and

[0019] A drive control device is used to send a light emission pulse signal and a preheating pulse train signal to an insulated gate bipolar transistor element in a pre-burning maintenance circuit according to the laser thermal stability maintenance method of any one of the first aspects.

[0020] Thirdly, a laser is provided that includes the laser power supply system of the second aspect.

[0021] The aforementioned laser thermal stability maintenance method, laser power supply system, and laser, when the current output frequency of the laser is lower than a preset frequency threshold, generate a preheating pulse train signal and mix it with the emission pulse signal to compensate for the low-frequency output condition. This increases the total power generated by the laser and maintains the total power of the laser within the thermally stable power range under the drive of the preheating pulse train signal and the emission pulse signal. As a result, the laser's energy consumption increases while the output frequency remains unchanged, thereby overcoming the thermal transmission effect of the laser crystal, improving the thermal stability of the laser, and thus improving the stability of the laser beam emitted by the laser. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the laser power supply system in some embodiments;

[0023] Figure 2 This is a flowchart illustrating the laser thermal stability maintenance method in some embodiments;

[0024] Figure 3 This is a schematic diagram of the preheating pulse train signal structure in some embodiments;

[0025] Figure 4 This is a schematic diagram illustrating the relationship between the preheating pulse train signal, the reheating pulse train signal, and the light emission pulse signal in some embodiments;

[0026] Figure 5 This is a schematic diagram of the pre-combustion sustaining circuit in one embodiment. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] The following describes the application scenarios of the laser thermal stability maintenance method involved in this application, with reference to... Figure 1 As shown, Figure 1 The diagram illustrates the structure of a laser power supply system to which the laser thermal stability maintenance method is applied in some embodiments. The laser thermal stability maintenance method provided in this application can be applied to... Figure 1The laser power supply system shown.

[0029] Specifically, the laser power supply system includes a charging circuit 10, an energy storage capacitor network 20, a high-voltage triggering circuit 30, a drive control device 40, a pre-burning sustaining circuit 60, and a pump source 50; wherein, the pre-burning sustaining circuit 60 includes an insulated-gate bipolar transistor element; wherein,

[0030] The charging circuit 10 is used to charge the energy storage capacitor network 20;

[0031] The high-voltage trigger circuit 30 is used to output a trigger voltage to the pump source 50 to ionize the inert gas inside the pump source 50.

[0032] Energy storage capacitor network 20 is used to discharge to the pump source according to the light pulse signal; and

[0033] The drive control device 40 is used to send light-emitting pulse signals and preheating pulse train signals to the insulated gate bipolar transistor elements in the pre-combustion sustaining circuit 60.

[0034] More specifically, the current emission frequency of the laser's emission pulse signal is obtained; in response to the current emission frequency being less than a preset frequency threshold, a preheating pulse train signal is generated before the emission pulse signal is generated. The preheating pulse train signal and the emission pulse signal cause the insulated gate bipolar transistor (IGBT) element (pre-burning sustaining circuit 60) in the laser drive power supply system to turn on, thereby driving the total power generated by the laser to be maintained within a preset thermally stable power range.

[0035] In some embodiments, the drive control device may include a microcontroller, or a drive control device based on an MCU (Microcontroller Unit), and may further include a processor, a memory, or other devices. The memory stores computer instructions, and the processor or control unit executes the computer instructions to acquire the current emission frequency of the laser's emission pulse signal. In response to the current emission frequency being less than a preset frequency threshold, a preheating pulse train signal is generated before the emission pulse signal is generated. Under the drive of the preheating pulse train signal and the emission pulse signal, the total power generated by the laser is maintained within a preset thermally stable power range.

[0036] Because the total power of a laser is relatively high at higher output frequencies (e.g., 100 Hz) and relatively low at lower output frequencies (e.g., 5 Hz), both low-frequency and high-frequency output can cause significant thermal deformation of the laser crystal. This is due to the temperature inconsistency between the internal and surface temperatures of the laser crystal. However, when the total power of the laser reaches a certain preset value, the thermal deformation of the laser crystal becomes relatively small. At this point, the laser crystal can be considered to have reached its thermal stability range, and the total power generated by the laser has reached the thermally stable power range, resulting in a more uniform laser spot size. The solution proposed in this application can compensate for the heat generated during low-frequency output by increasing the total power of the laser output, ensuring that the total power generated by the laser remains within the thermally stable power range regardless of the output frequency, thereby maintaining the laser crystal in a thermally stable state.

[0037] Therefore, the laser power supply system described above in the embodiments of this application, when the current emission frequency of the emission pulse signal is low, that is, when the current total power of the laser is lower than the lower limit of the preset thermal stability power range, generates a preheating pulse train signal through a drive control device and mixes the preheating pulse train signal with the emission pulse signal, thereby compensating for the low-frequency emission condition by increasing the total power generated by the laser. Under the drive of the preheating pulse train signal and the emission pulse signal, the total power generated by the laser is maintained within the thermal stability power range. This allows the energy consumption of the laser to increase while the emission frequency remains unchanged, thereby overcoming the thermal transmission effect of the laser crystal, improving the thermal stability of the laser, and improving the stability of the laser spot emitted by the laser.

[0038] In some embodiments, such as Figure 2 As shown, Figure 2 The following are schematic flowcharts illustrating laser thermal stability maintenance methods in some embodiments, which may specifically include the following steps:

[0039] Step S202: Obtain the current emission frequency of the laser's emission pulse signal;

[0040] In this step, the laser can be configured with multiple emission frequencies to support laser operations at various emission frequencies. For example, different emission levels can be set to correspond to different emission frequencies. More specifically, the emission frequency of the currently selected level can be obtained by identifying the currently selected level mode, and this frequency can be used as the current emission frequency.

[0041] Step S204: In response to the current emission frequency being less than a preset frequency threshold, a preheating pulse train signal is generated before the emission pulse signal is generated; wherein, driven by the preheating pulse train signal and the emission pulse signal, the total power generated by the laser is maintained within a preset thermally stable power range.

[0042] In this step, when the current emission frequency of the laser is less than the preset frequency threshold, that is, when the laser emits light at a lower frequency, the laser crystal cannot reach a thermally stable state due to insufficient energy absorption, resulting in unstable and inconsistent laser spot sizes. Therefore, a preheating pulse train signal is generated before the emission pulse signal and doped with it to thermally compensate the emission pulse signal, and the total power generated by the laser under the drive of the preheating pulse train signal and the emission pulse signal is controlled to be maintained within the thermally stable power range.

[0043] The preheating pulse train signal is used for energy compensation. Each sub-pulse in the preheating pulse train signal does not achieve light emission; that is, the driving power of each sub-pulse at its pulse width and frequency is less than the threshold for laser emission. Therefore, thermal compensation can be achieved without interference or excess light emission. The thermally stable power range refers to the power range that can maintain the laser crystal in the laser in a thermally stable state to overcome the heat transmission effect.

[0044] In practical applications, after the laser is started, if the current output frequency is low (below a preset frequency threshold), it can enter a preheating mode. In this mode, a preheating pulse train signal is continuously generated by the drive control device and applied to the IGBT switch in the laser's discharge circuit. This drives the laser's pump source to emit pulsed light, which irradiates the laser crystal, causing it to preheat. Upon receiving the user's output command, the drive control device generates a emission pulse signal. Because the laser crystal has been preheated, it reaches a thermally stable state. Driven by the preheating pulse train signal and the emission pulse signal, the total power generated by the laser can be maintained within a preset thermally stable power range. Therefore, this improves the consistency and stability of the laser spot size emitted by the laser.

[0045] In the above embodiments, when the current emission frequency of the laser is lower than a preset frequency threshold, a preheating pulse train signal is generated and mixed with the emission pulse signal to compensate for the low-frequency emission condition. This increases the total power generated by the laser and maintains the total power of the laser within the thermally stable power range under the drive of the preheating pulse train signal and the emission pulse signal. As a result, the energy consumption of the laser increases while the emission frequency remains unchanged, thereby overcoming the thermal transmission effect of the laser crystal, improving the thermal stability of the laser, and thus improving the stability of the laser spot emitted by the laser.

[0046] In some embodiments, the method further includes: determining whether the current total power of the laser is lower than the lower limit of a preset thermally stable power range; if yes, proceeding to the step of generating a preheating pulse train signal before generating the emission pulse signal; if no, stopping the generation of the preheating pulse train signal.

[0047] In this embodiment, generally, the higher the current emission frequency of the laser, the greater its current total power, and vice versa. Specifically, the current total power of the laser can be dynamically calculated and compared with the lower limit of a preset thermally stable power range to determine whether the current total power has reached the thermally stable power range. If the current total power is lower than the lower limit of the preset thermally stable power range, a preheating pulse train signal is generated for thermal compensation. If the current total power reaches the thermally stable power range, the generation of the preheating pulse train signal can be stopped. By dynamically determining the total emission power of the laser, the addition of a preheating pulse train signal can be dynamically controlled according to the different emission conditions of the laser at different power levels, making the laser operation more stable.

[0048] In some embodiments, generating a preheating pulse train signal includes: generating a plurality of sub-pulses using a drive control device; and forming a pulse group with the plurality of sub-pulses, forming a pulse cluster with the plurality of pulse groups, and forming a preheating pulse train signal with at least one pulse cluster.

[0049] In this embodiment, reference can be made to Figure 3 As shown, the preheating pulse train signal can adopt a multi-level nested structure, such as... Figure 3 As shown in the diagram, the content circled in the figure is an enlarged view of the content indicated by the corresponding arrow. More specifically, a drive control device can be used to generate multiple sub-pulses 10 (first-level signals) of the first-level frequency. Every s sub-pulses form a group to generate a pulse group 20 (second-level signal), with the frequency of the pulse group 20 being the second-level frequency. Every t pulse groups 20 form a group to generate a pulse cluster 30 (third-level signal), with the frequency of the pulse cluster 30 being the third-level frequency. At least one pulse cluster 30 constitutes a preheating pulse train signal. Wherein, s and t are positive integers greater than 1, preferably, t is greater than s.

[0050] In some embodiments, the frequency of the sub-pulse is greater than the frequency of the pulse group, and the frequency of the pulse group is greater than the frequency of the pulse cluster. That is, the first-level frequency is greater than the second-level frequency, and the second-level frequency is greater than the third-level frequency.

[0051] In some embodiments, continue to refer to Figure 3As shown, the interval between sub-pulses 10 in each pulse group 20 is the first interval 101, the interval between pulse groups 20 in each pulse cluster 30 is the second interval 201, and the interval between pulse clusters 30 is the third interval 301; wherein, the first interval 101 is smaller than the second interval 201, and the second interval 201 is smaller than the third interval 301.

[0052] The above embodiments, by constructing a multi-level preheating pulse train signal with a contained structure, can make the preheating pulse train signal more stable, thereby improving the thermal stability of the laser crystal. Moreover, by controlling the interval between pulses at each level, the driving power of the preheating pulse train signal can be adjusted, thereby achieving flexible adjustment of the laser crystal thermal compensation.

[0053] In some embodiments, the drive control device includes a microcontroller, which generates multiple sub-pulses by: obtaining the period information of the drive pulse by configuring the frequency division information and reload information of the microcontroller's timer, and obtaining the sub-pulses by controlling the number, frequency and duty cycle of the drive pulses; wherein the drive power of the sub-pulses is less than the light output threshold of the laser.

[0054] The above embodiments, for example, can be generated using an STM32 microcontroller or other modulation waveform generator via DMA (Direct Memory Access) mode. Figure 3 The PWM (Pulse-width modulation) drive pulses shown can be used to construct sub-pulses for preheating pulse trains by setting appropriate timer division and reload information, and adjusting the number, frequency and duty cycle of the drive pulses.

[0055] In some embodiments, the method further includes: inserting n driving pulses with zero duty cycle between each pulse group to separate each pulse group, and inserting m driving pulses with zero duty cycle between each pulse group to separate each pulse cluster; wherein n and m are positive integers, and m is greater than n.

[0056] In this embodiment, since the period and magnitude of the drive pulses generated by the microcontroller are constant, the duty cycle can be adjusted. In particular, by inserting drive pulses with a zero duty cycle between each pulse group to separate each pulse group, and by inserting drive pulses with a zero duty cycle between each pulse group to separate each pulse cluster, a preheating pulse train signal with a multi-level containment structure that can be flexibly adjusted and has a variable frequency can be realized.

[0057] In this embodiment, a simple and low-cost microcontroller is used as the driving and control device. A preheating pulse train signal with multiple frequencies and multiple containment structures is created using a microcontroller that can only emit pulses with a constant period. This reduces equipment costs while improving the flexibility of dynamic adjustment of the preheating pulse train signal. For example, the frequency of the preheating pulse train signal can be flexibly controlled by adjusting the number of pulse groups, the interval between sub-pulses, the interval between pulse groups, the interval between pulse clusters, etc., so that the total power of the laser under the drive of the preheating pulse train signal and the emission pulse signal is maintained within a preset thermally stable power range. Therefore, the dynamic adjustment capability of the thermal stability of the laser crystal can be improved.

[0058] In some embodiments, reference Figure 4 As shown, Figure 4 A schematic diagram showing the relationship between the preheating pulse train signal, the reheating pulse train signal, and the light emission pulse signal in some embodiments is shown.

[0059] Specifically, the method further includes: inserting a reheating pulse train signal 200 between the preheating pulse train signal 100 preceding the light emission pulse signal 300 and the light emission pulse signal 300; wherein the interval 402 between the reheating pulse train signal 200 and the light emission pulse signal 300 is smaller than the interval 401 between the reheating pulse train signal 200 and the preheating pulse train signal 100.

[0060] In this embodiment, a reheating pulse train signal with a higher frequency and narrower pulse width is added between the emission pulse signals. The reheating pulse train signal can enhance the pumping effect on the crystal, thereby improving the pumping efficiency and further improving the stability of the laser operation. For example, a reheating pulse train signal can be connected between each emission pulse signal, and the frequency of the reheating pulse train signal is higher than that of the preheating pulse train signal.

[0061] In some embodiments, a laser power supply system is also provided, which may be referred to Figure 1 As shown above, the description of the laser power supply system will not be repeated here.

[0062] In some embodiments, reference Figure 5 As shown, Figure 5 The diagram shows a schematic of the pre-combustion sustaining circuit in some embodiments, wherein, after the laser enters the preheating stage, by providing... Figure 5 The insulated gate bipolar transistor (IGBT) element in the laser is subjected to a high-frequency, narrow-pulse preheating pulse train signal, which causes the xenon lamp (pump source) to emit pulsed light to heat the crystal of the laser, bringing it to the thermally stable range. This overcomes the thermal lensing effect and keeps the size of the laser spot emitted by the laser essentially unchanged.

[0063] In some embodiments, the laser power supply system may further include a pulse limiting circuit, which can be used to limit the pulse width of the sub-pulses in the preheating pulse train signal so that the pulse width of the sub-pulses in the preheating pulse train signal reaches a preset standard, thereby avoiding unnecessary laser output due to excessively wide sub-pulse widths. In other words, unnecessary laser output is further avoided while compensating for energy.

[0064] In some embodiments, a laser is also provided, which includes the laser power supply system described above. The laser may be a solid-state laser, such as a pulsed erbium laser (YAG), and may be used in fields such as laser aesthetics and laser therapy.

[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for maintaining the thermal stability of a laser, the method comprising: Obtain the current emission frequency of the laser's emission pulse signal; In response to the current emission frequency being less than a preset frequency threshold, a preheating pulse train signal is generated before the emission pulse signal is generated; wherein, driven by the preheating pulse train signal and the emission pulse signal, the total power generated by the laser is maintained within a preset thermally stable power range; wherein, the preheating pulse train signal adopts a multi-level nested structure, and generating the preheating pulse train signal includes: generating multiple sub-pulses; forming a pulse group with multiple sub-pulses; forming a pulse cluster with multiple pulse groups; and forming the preheating pulse train signal with at least one pulse cluster; wherein, the frequency of the sub-pulses is a first-level frequency, the frequency of the pulse group is a second-level frequency, and the frequency of the pulse cluster is a third-level frequency, the first-level frequency being greater than the second-level frequency, and the second-level frequency being greater than the third-level frequency; wherein... A re-preheating pulse train signal is inserted between the preheating pulse train signal preceding the light-emitting pulse signal and the light-emitting pulse signal; wherein the interval between the re-preheating pulse train signal and the light-emitting pulse signal is smaller than the interval between the re-preheating pulse train signal and the preheating pulse train signal. The pulse width of the sub-pulse in the preheating pulse train signal is limited by a pulse limiting circuit so that the pulse width of the sub-pulse reaches a preset standard and the driving power of the sub-pulse is less than the light output threshold of the laser.

2. The method according to claim 1, characterized in that, The method further includes: Determine whether the current total power of the laser is lower than the lower limit of the preset thermally stable power range; if yes, proceed to the step of generating a preheating pulse train signal before generating the emission pulse signal; if no, stop generating the preheating pulse train signal.

3. The method according to claim 1, characterized in that, The generation of multiple sub-pulses includes: Multiple sub-pulses are generated using a drive control device.

4. The method according to claim 1, characterized in that, The interval between sub-pulses in each pulse group is the first interval, the interval between pulse groups in each pulse cluster is the second interval, and the interval between pulse clusters is the third interval; wherein, the first interval is smaller than the second interval, and the second interval is smaller than the third interval.

5. The method according to claim 3, characterized in that, The drive control device includes a microcontroller, and the generation of multiple sub-pulses using the drive control device includes: By configuring the frequency division information and reload information of the timer of the drive control device, the period information of the drive pulse is obtained. By controlling the number, frequency and duty cycle of the drive pulse, the sub-pulse is obtained.

6. The method according to claim 5, characterized in that, The method further includes: n drive pulses with zero duty cycle are inserted between each of the pulse groups to separate each pulse group, and m drive pulses with zero duty cycle are inserted between each of the pulse groups to separate each pulse cluster; where n and m are positive integers, and m is greater than n.

7. A laser power supply system, the system comprising a charging circuit, an energy storage capacitor network, a high-voltage triggering circuit, a drive control device, a pre-burning sustaining circuit, and a pump source; wherein, The pre-combustion sustaining circuit includes an insulated-gate bipolar transistor element; wherein... The charging circuit is used to charge the energy storage capacitor network; The high-voltage triggering circuit is used to output a triggering voltage to the pump source to ionize the inert gas inside the pump source. The energy storage capacitor network is used to discharge to the pump source according to the light-emitting pulse signal; and The drive control device is used to send a light emission pulse signal and a preheating pulse train signal to the insulated gate bipolar transistor element in the pre-burning maintenance circuit according to the laser thermal stability maintenance method according to any one of claims 1 to 6.

8. A laser comprising the laser power supply system of claim 7.

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