WO2020103399A1 - 电光q开关双频双脉冲激光碎石系统 - Google Patents

电光q开关双频双脉冲激光碎石系统

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Publication number
WO2020103399A1
WO2020103399A1 PCT/CN2019/084444 CN2019084444W WO2020103399A1 WO 2020103399 A1 WO2020103399 A1 WO 2020103399A1 CN 2019084444 W CN2019084444 W CN 2019084444W WO 2020103399 A1 WO2020103399 A1 WO 2020103399A1
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electro
switch
circuit
optic
voltage
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PCT/CN2019/084444
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English (en)
French (fr)
Inventor
杜金波
邵建华
董家佐
刁凌天
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吉林省科英激光股份有限公司
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Application filed by 吉林省科英激光股份有限公司 filed Critical 吉林省科英激光股份有限公司
Priority to US16/762,919 priority Critical patent/US11364078B2/en
Priority to EP19883329.5A priority patent/EP3711819B1/en
Publication of WO2020103399A1 publication Critical patent/WO2020103399A1/zh

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A61B18/26—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor for producing a shock wave, e.g. laser lithotripsy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
    • H01S3/1123—Q-switching
    • H01S3/115—Q-switching using intracavity electro-optic devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/163—Solid materials characterised by a crystal matrix
    • H01S3/164—Solid materials characterised by a crystal matrix garnet
    • H01S3/1643—YAG
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
    • A61B2018/00505—Urinary tract
    • A61B2018/00511—Kidney
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
    • A61B2018/00505—Urinary tract
    • A61B2018/00517—Urinary bladder or urethra

Definitions

  • the invention relates to the technical field of optical-based medical devices, and in particular to an electro-optic Q-switch dual-frequency dual-pulse laser lithotripsy system.
  • extracorporeal shock wave lithotripsy In order to crush the stones in the digestive system and urinary system, humans have invented various methods such as extracorporeal shock wave lithotripsy, hydroelectric lithotripsy, ultrasonic lithotripsy, and laser lithotripsy. Because of the inherent advantages of laser lithotripsy, in addition to the first choice of extracorporeal shock waves for kidney stones, other methods have been basically replaced by laser lithotripsy. In the laser lithotripsy method, Ho: Cr: Tm: YAG 2.1 micrometer static laser and Nd: YAG 1.064 + 0.532 micrometer dual-frequency dual-pulse Q-switch laser are currently used clinically.
  • the above two laser lithotripters have completely different mechanisms of action.
  • the Q-switch dual-frequency dual-pulse Nd: YAG laser's gravel effect is that after the stone is irradiated with high-power density laser, the atoms evaporated on the surface are ionized by high-energy laser photons, and quickly form a plasma, which then absorbs the subsequent The laser energy rapidly expands and collapses, and the resulting shock waves and micro-jets can break the stones.
  • the holmium laser mainly absorbs the great laser energy by water and stones, and generates thermal drilling and thermal blasting.
  • the use of Q-switched Nd: YAG laser can achieve high peak power (about 1 ⁇ 10 5 W) with only a small energy (about 100mJ), even against the ureter wall 1000 pulses will not cause damage to these soft tissues.
  • Holmium laser lithotripsy usually has an energy of up to about 1000-3000mJ, but the peak power is only 1 ⁇ 10 4 W, so under normal circumstances, once the fiber is not aligned and hit the ureter wall, a pulse is enough to cause perforation of the wall . Therefore, the holmium laser stone crusher that can be produced in China can only be used to crush large-sized stones, but the effect is not good for small stones, and it is more dangerous.
  • a Q-switch Nd: YAG laser lithotripsy system (U-100 and U-100Plus, the latter is an upgraded version of the former) is disclosed.
  • the optical path is 20-30 meters long
  • the optical fiber is used to extend the length of the laser resonator, and the passive Q-switched crystal is used to compress the laser pulse width, and finally the laser pulse output of 1 ⁇ s is realized.
  • this structure has the following shortcomings: First, if you want to change the output pulse width, you need to replace the fiber length inside the optical path, which requires complex readjustment of the system, which cannot be used in clinical use; Second, the structure The passive Q-switched crystal is used to achieve 1 ⁇ s laser output.
  • this structure Due to the high loss of the passive Q-switched resonant cavity, the electro-optical efficiency of the whole machine is low; the third is that this structure uses long fiber and Cr4 +: YAG passive Q-switching. It can only output 1 ⁇ s dynamic lithotripsy pulse. However, in actual clinical use, it is often encountered that a layer of soft tissue structure is wrapped around the stone. Before lithotripsy, the soft tissue must be vaporized and peeled off. This lithotripter cannot be done.
  • the present invention provides an electro-optic Q-switch dual-frequency dual-pulse laser lithotripsy system.
  • Electro-optic Q-switch dual-frequency dual-pulse laser lithotripsy system including total reflection mirror, electro-optic Q-switch component, drive circuit, controller, pump source, gain medium, output mirror, first focusing mirror, frequency doubling crystal, second A focusing mirror, a coupling lens and an output fiber; the electro-optic Q-switch assembly and the gain medium are located between the total reflection mirror and the output mirror; the drive circuit is connected to the electro-optic Q-switch assembly; the controller is connected to the electro-optic Q-switch assembly With the pump source, the controller controls the pump source to work, and the controller controls the voltage on the electro-optic Q-switch assembly by controlling the drive circuit;
  • the controller controls the pump source to generate pump light to irradiate the gain medium, and the controller controls the drive circuit.
  • an optical resonant cavity is formed between the total reflection mirror and the output mirror.
  • the laser beam is output through the output mirror.
  • the laser beam is converged by the first focusing mirror, frequency-doubled by the frequency-doubling crystal part, exiting parallel after the second focusing mirror, converging and coupling by the coupling lens, and output fiber
  • the laser beam is a dynamic laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s or a static laser beam with a pulse width of 200 ⁇ s to 300 ⁇ s.
  • the output The mirror outputs a laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s.
  • the output mirror outputs a laser beam with a pulse width of 200 ⁇ s to 300 ⁇ s.
  • ⁇ represents the output of the laser beam output by the output mirror wavelength.
  • the electro-optic Q-switch assembly includes a Pockels cell and a polarizer, and the driving circuit is connected to both ends of the Pockels cell.
  • the electro-optical Q-switch assembly further includes a quarter wave plate, the quarter wave plate is located between the total reflection mirror and the Pockels cell, when the voltage across the Pockels cell gradually When the loss is reduced and the loss of the Pockels cell is gradually reduced and the loss of the Pockels cell has been kept in dynamic balance with the gain of the gain medium, the laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s is output.
  • the driving circuit includes a shaping circuit connected to the controller, a delay driving circuit connected to the shaping circuit, a depressurizing circuit connected to the delay driving circuit and one end of the Pockels box, and a constant voltage connected to the other end of the Pockels box Circuit
  • the decompression circuit includes a second DC high-voltage power supply, N decompression sub-circuits and a second ground terminal connected in series in series
  • the second DC high-voltage power supply is connected in series with N decompression sub-circuits
  • the delay drive circuit includes N delay drive sub-circuits
  • the delay drive sub-circuits and the depressurization sub-circuits are connected in a one-to-one correspondence, N ⁇ 3.
  • the constant voltage circuit includes a first ground terminal.
  • the constant voltage circuit further includes a first DC high voltage power supply, a high voltage switch connected to the output end of the first DC high voltage power supply, and a filter circuit connected to the high voltage switch, and the first ground terminal is connected to the filter circuit.
  • the filter circuit is composed of capacitors and resistors connected in parallel.
  • the decompression sub-circuit includes a voltage-dividing MOS switch, a voltage-dividing capacitor and a discharge current limiting resistor connected in sequence, and the voltage-dividing MOS switch is connected to a corresponding delay driving sub-circuit.
  • the pump source is a xenon lamp
  • the gain medium is an Nd: YAG crystal.
  • the drive circuit and pump source are controlled by the controller, so that the optical resonant cavity can output a laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s, and can also output a laser beam with a pulse width of 200 ⁇ s to 300 ⁇ s.
  • the dynamic laser beam of 1 ⁇ s to 1.5 ⁇ s output by the invention can realize the crushing of stones, and the static laser beam of pulse width of 200 ⁇ s-300 ⁇ s output can realize the cutting of soft tissues around the stones.
  • Pulse width is easy to change, simple structure, easy to use, suitable for clinical use.
  • the electro-optical Q-switch component is used in the optical resonant cavity to realize the laser output with a pulse width of 1 ⁇ s to 1.5 ⁇ s, which reduces the loss of the resonant cavity, that is, lowers the threshold value and improves the electro-optical efficiency.
  • the invention realizes the output of two wavelength lasers through an optical path system.
  • the short-wave laser has higher photon energy, which is conducive to the ignition of the plasma.
  • the long-wave energy is absorbed by the plasma to enhance the strength of the gravel.
  • Two lasers of different wavelengths It is suitable for different stages of crushed stone, and can achieve good crushing effect.
  • the main pulse laser beam is followed by the output of the sub-pulse laser beam, because the energy of these sub-pulse lasers is absorbed by the generated plasma, It will greatly enhance the strength of shock wave lithotripsy, so the present invention can crush white and hard cystine stones which can not be opened by previous lithotripters.
  • Figure 1 is the structure diagram of the U-100 laser lithotripsy system of the German WOM company.
  • FIG. 2 is a schematic diagram of the pressurized Q-switched optical path of the present invention.
  • Figure 3 is a schematic diagram of a pressurized Q-switched drive circuit.
  • Fig. 4 is a waveform diagram of a conventional fast-switching electro-optic Q-switched xenon lamp light waveform, optical cavity loss and laser intensity waveform.
  • FIG. 5 is a schematic diagram of the mechanism for controlling the output laser of the slow-switching pressurized Q-switch drive circuit.
  • Fig. 6 is a schematic diagram of a slow-switching pressurized Q-switching drive circuit controlling the output of a single pulse laser.
  • Fig. 7 is a static laser waveform diagram for peeling soft tissue.
  • Fig. 8 is a dynamic laser followed by a sub-pulse laser waveform.
  • Electro-optic Q-switch dual-frequency double-pulse laser lithotripsy system including total reflection mirror 1, electro-optic Q-switch assembly, drive circuit 4, controller 14, pump source 13, gain medium 6, output mirror 7, first focusing mirror 8 , Frequency doubling crystal 12, second focusing mirror 9, coupling lens 10 and output fiber 11.
  • the electro-optical Q-switch assembly and the gain medium 6 are located between the total reflection mirror 1 and the output mirror 7.
  • the driving circuit 4 is connected to the electro-optical Q-switch assembly and controls the opening and closing of the electro-optical Q-switch assembly.
  • the controller 14 is connected to the electro-optic Q-switch assembly and the pump source 13. The controller 14 controls the pump source 13 to work.
  • the controller 14 controls the drive circuit 4, and controls the voltage acting on the electro-optic Q-switch assembly through the drive circuit 4.
  • the controller 14 controls the pump source 13 to start pumping, the pump source 13 generates pump light to irradiate the gain medium 6, and the controller 14 controls the driving circuit 4, when the voltage applied to the electro-optic Q-switch assembly by the driving circuit 4 has a voltage difference At this time, an optical resonant cavity is formed between the total reflection mirror 1 and the output mirror 7.
  • the laser beam is output through the output mirror 7, and the laser beam output by the output mirror 7 is 1 ⁇ s ⁇ 1.5 ⁇ s pulse width laser beam or 200 ⁇ s ⁇ 300 ⁇ s pulse width laser beam.
  • the laser beam output from the output mirror 7 is condensed by the first focusing mirror 8 and incident on the frequency doubling crystal 12, and partially frequency-doubled by the frequency doubling crystal 12 (because the frequency doubling crystal 12 has frequency doubling efficiency, part of the laser beam frequency doubling , The other part of the frequency remains unchanged) incident on the second focusing mirror 9 and parallel out of the second focusing mirror 9 onto the coupling lens 10, converging and coupling through the coupling lens 10 and then transmitted to the output fiber 11 and output system through the output fiber 11 For medical treatment.
  • the output mirror 7 outputs the laser beam through the frequency doubling crystal 12 so that the laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s or the laser beam with a pulse width of 200 ⁇ s to 300 ⁇ s becomes a dual-frequency laser beam output.
  • the electro-optical Q-switch dual-frequency dual-pulse laser lithotripsy system of the present invention controls the driving circuit 4 and the pump source 13 through the controller 14, so that the optical resonant cavity can output a dynamic laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s.
  • the dynamic laser beam can crush stones; the control of the controller 14 enables the optical resonant cavity to output a static laser beam with a pulse width of 200 ⁇ s to 300 ⁇ s.
  • the pulse width of the static laser beam can realize the cutting of soft tissue around the stone. Therefore, the present invention is used
  • the laser lithotripsy system can not only crush stones, but also remove soft tissues around stones.
  • the output fiber 11 is not aligned with the stones, it will not cause harm to the human body. For example, once the output fiber 11 hits the wall of the ureter, it will not cause perforation of the tube wall, and the safety is high. In addition, the output fiber 11 is not used in the optical resonant cavity.
  • the switching of lasers with different pulse widths does not require complicated replacement of the internal output fiber 11 in the optical path.
  • the controller 14 controls the drive circuit 4 and the drive circuit 4 to control the electro-optic Q-switch assembly. It can be realized without complicated readjustment of the optical path, and the pulse width can be easily changed, which is suitable for clinical use.
  • An electro-optical Q-switching component (active electro-optical Q-switch) is used in the optical resonant cavity to realize the output of a dynamic laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s.
  • the invention realizes the output of two wavelength lasers through an optical path system.
  • the short-wave laser has higher photon energy, which is beneficial to the ignition of the plasma, the long-wave energy is absorbed by the plasma, and the strength of the crushed stone is enhanced, and both can achieve good crushed stone. effect.
  • the electro-optical Q-switch dual-frequency dual-pulse laser lithotripsy system of the present invention After the main pulse laser beam is followed by the output of the sub-pulse laser, since the energy of these sub-pulse lasers is absorbed by the generated plasma, it will be extremely The strength of shock wave crushed stone is enhanced, so the white and hard cystine stones which can not be opened by the previous crusher can be crushed in the present invention.
  • the invention has completely independent innovation in technology, and its function exceeds that of the world's advanced laser lithotripsy system.
  • the invention is capable of crushing large-scale stones, cutting soft tissues around the stones, having good crushing effect and crushing capacity It is a high-level medical system with many advantages, such as strong, efficient energy conversion, easy to change pulse width, simple structure, easy to use and so on.
  • the controller 14 controls the driving circuit 4 to gradually increase or decrease the voltage applied to the electro-optic Q-switch assembly, the loss of the electro-optic Q-switch assembly is gradually reduced, and the loss of the electro-optic Q-switch assembly and the gain of the gain medium are kept dynamic
  • the basically stable laser oscillation is always maintained in the optical resonant cavity (can be referred to as resonant cavity), and the output mirror 7 can output a laser beam with a pulse width of 1 ⁇ s to 1.5 ⁇ s.
  • the controller 14 controls the driving circuit 4 to output a laser beam with a pulse width of 200 ⁇ s to 300 ⁇ s when the voltage on the electro-optic Q-switch assembly is ⁇ / 4, and ⁇ represents the wavelength of the laser beam output by the output mirror 7, that is, the optical resonator The wavelength of the output laser beam.
  • FIG. 2 is a pressurized Q-switched optical path.
  • the electro-optical Q-switch assembly includes Pockels cell 3, polarizer 5 and quarter wave plate 2, quarter wave plate 2, Pockel cell 3 and polarizer 5 is sequentially arranged between the total reflection mirror 1 and the gain medium, and the corresponding drive circuit 4 is called a pressurized Q-switch drive circuit. If the electro-optical Q-switch assembly does not include the quarter wave plate 2, it is a depressurized Q-switched optical path, and the corresponding circuit is called a decompressed Q-switched drive circuit.
  • the driving circuit 4 is connected to both ends of the Pockels box 3.
  • the gain medium is a solid laser rod 6, which specifically uses an Nd: YAG crystal
  • the pump source 13 uses a xenon lamp, that is, a 1064 nm laser is output, and the 1064 nm laser is frequency-doubled by a frequency-doubling crystal to obtain a 532 nm laser.
  • the frequency doubling crystal 12 uses a KDP crystal, and the first focusing mirror 8 is used to enhance the frequency doubling efficiency.
  • the laser energy with a wavelength of 1064 nm occupies about 80% of the total energy
  • the laser energy with a wavelength of 532 nm occupies about 20% of the total energy.
  • FIG. 3 is a schematic diagram of a pressurized Q-switch drive circuit.
  • the drive circuit 4 includes a shaping circuit 404, a delay drive circuit 403, a depressurization circuit 402, and a constant voltage circuit. Both ends of the Pockels cell 3 are loaded between two points of the decompression circuit 402 and the output terminals a and b of the constant voltage circuit.
  • the constant voltage is composed of a first DC high voltage power supply 4011, a high voltage switch 4012 connected to the output end of the first DC high voltage power supply 4011, a filter circuit 4013 connected to the high voltage switch 4012, and a first ground terminal connected to the filter circuit 4013,
  • the filter circuit 4013 is composed of capacitors and resistors connected in parallel.
  • the depressurization circuit 402 includes a second DC high-voltage power supply 4021, a multi-stage series of N depressurization sub-circuits 4022 connected to the output of the second DC high-voltage power supply 4021, a second ground terminal, a voltage-dividing capacitor connected in series, and a discharge current limiting
  • the resistor and the voltage-dividing MOS switch form a decompression sub-circuit 4022, that is, a second DC high-voltage power supply 4021, a voltage-dividing capacitor and a second ground terminal are connected in series, and the number of decompression sub-circuits 4022 is at least three.
  • each voltage-dividing MOS switch serves as the control terminal of the decompression sub-circuit 4022, and is subjected to multiple delays output by the trigger circuit (the trigger circuit is composed of a signal source, a shaping circuit 404, and a delay driving circuit 403 together forming a trigger circuit) Controlled by the signal.
  • the trigger circuit is composed of a signal source, a shaping circuit 404, and a delay driving circuit 403 together forming a trigger circuit
  • the “signal source” in FIG. 3 is the control signal output by the controller 14.
  • the signal source is the control signal output by the controller 14. Since the signal provided by the controller 14 is a weak signal, and the parameters such as the amplitude and time of the control signal cannot directly drive the delay drive circuit 403 at the back, processing is required to control the signal After passing through the shaping circuit 404, it becomes a signal usable by the delay drive circuit 403.
  • the first delay drive signal output by the first delay drive sub-circuit 4031 of the delay drive circuit 403 is loaded on the first voltage-dividing MOS switch , Forming a first-stage RC discharge circuit, the voltage across the corresponding first voltage-dividing capacitor will drop; the second delay drive signal output from the second delay drive sub-circuit 4031 in the delay drive circuit 403 is loaded in the second After the voltage-dividing MOS switch is formed, a second-stage RC discharge circuit is formed, and the voltage across the corresponding second voltage-dividing capacitor will drop; accordingly, the third delay in the third delay driving sub-circuit 4031 of the driving circuit 4 outputs the third delay The time driving signal and the subsequent delay driving sub-circuit 4031 respectively delay and act on the corresponding voltage-dividing MOS switches in turn, the process is the same as above.
  • the point b of the constant voltage end of the Pockels box 3 in FIG. 3 can be directly grounded. That is, the constant voltage circuit includes only the first ground terminal, so that since the depressurization circuit 402 is sequentially turned on, the potential at point a of the transformer terminal 3 of the Pockels cell 3 gradually decreases, and the potential at the constant voltage terminal is always 0, so Puck The voltage at both ends of the Erbox 3 still showed a downward trend, and a depressurized electro-optic Q-switch was implemented.
  • Each delayed drive sub-circuit 4031 corresponds to the decompressed sub-circuit 4022 corresponding to the delayed drive signal.
  • the delayed drive sub-circuit 4031 is the same as the decompressed sub-circuit 4022.
  • the delayed driving signal, each decompression sub-circuit 4022 and its internal components are named with “first”, “second", “third”, etc., which are only for the sequential order and component distinction.
  • the conventional electro-optical Q-switch / electro-optical Q-switch assembly is a fast switch, and the output laser pulse width is usually in the order of nanoseconds, as shown in the conventional fast-switching electro-optical Q-switching circuit output shown in FIG. 4
  • one end of the Pockels box 3 is loaded on the output end of the multi-stage series depressurization circuit 402, and the other end is loaded on the output end of the constant voltage circuit, and the depressurization circuit 402 is sequentially opened by an external control signal so that both ends of the depressurization circuit 402 The voltage gradually decreases, and finally the voltage across the Pockels cell 3 rises (or falls) step by step.
  • the discharge current limiting resistor in the decompression sub-circuit 4022 determines the voltage reduction speed of each stage in the series decompression sub-circuit 4022, and the delay driving sub-circuit 4031 controls the delay of decompression, that is, the decompression speed of each stage of the decompression circuit 402 can be Controllable, different cascading pressure relief delay is adjustable.
  • the controller 14 and the drive circuit 4 the laser oscillation is basically stabilized, and finally a smooth output of 1 to 1.5 microseconds is achieved, and the peak value of the top oscillation is less than 10% of the total amplitude.
  • the output laser pulse width is in the order of 1 ⁇ s by slowing down the switching speed.
  • a laser generating mechanism in FIG. 5 slow Q-switching a pressurized control mechanism outputs a laser driving circuit shown in the schematic, it can be seen from FIG. 5, the 0-t 0 time, a xenon lamp-pumped solid-state laser rod 6, solid-state laser rod 6
  • the number of inversion particles in the upper and middle energy levels continues to increase, the voltage across the Pockels cell 3 is zero, the optical cavity loss is high, the solid laser rod 6 stores energy and does not emit laser; during t 0- t 1 , Puck The voltage across the cell 3 gradually increases.
  • the loss of the optical resonator is less than the gain.
  • the laser starts to output in the optical resonator.
  • the number of particles in the upper level inversion is partially consumed.
  • the gain is less than the loss, the oscillation stops and the first light is output. pulse.
  • the voltage across the Pockels cell 3 slowly increases again, the loss of the optical resonant cavity is further reduced, the gain is greater than the loss, the number of partially inverted particles continues to be consumed, and the optical resonant cavity oscillates again. In this way, a second pulse is generated, and so on, and finally multiple light pulses can be generated.
  • the number of output optical pulses is the same as the number of voltage rises at both ends of the Pockels cell 3.
  • the width of each optical pulse is related to the amplitude of voltage rise and the speed of voltage rise.
  • the corresponding light emitting mechanism of the depressurization type Q-switching drive circuit is the same as that of the pressurization type.
  • Fig. 6 is a schematic diagram of a single pulse laser controlled by a slow switch pressurized Q-switch drive circuit.
  • the trigger delay of the voltage-dividing MOS switch is appropriately adjusted relative to Fig.
  • the delay time of the control signal of the voltage-dividing MOS switch is used to change the interval between the discharge moments of the two cascade circuits before and after, such as the interval between t 0 and t 1 , and the interval between t 1 and t 2 , thereby increasing the general
  • the rising speed of the voltage across the Kerr box 3 that is, the adjustment of the falling speed of the loss of the optical resonator, finally superimposes several different optical pulses into one optical pulse with a pulse width of about 1 ⁇ s for output.
  • the voltage across the Pockels cell 3 is exactly opposite to the output waveform of the pressurized Q-switching drive circuit (the voltage across the Pockels cell 3).
  • the time-varying waveform is the same.
  • FIGS. 4 to 6 are schematic representations of the relationship with time, so the ordinate does not give a specific unit.
  • Pressurized Q-switching drive circuit When it is necessary to output Q-switch dynamic laser lithotripsy, the controller 14 controls the ignition of the pulsed xenon lamp and simultaneously adds ⁇ / 4 waves (about 3400V) to the a and b ends of the Pockels cell 3 For the high voltage, the voltage difference across the Pockels cell 3 is 0. Due to the presence of the quarter wave plate 2, the resonant cavity is closed and the solid laser rod 6 stores energy.
  • the controller 14 sends out a control signal to turn on the delay drive sub-circuit 4031 one by one, the voltage on the voltage-dividing capacitor on each decompression sub-circuit 4022 is sequentially decompressed, and the a terminal of the Pockels box 3 The voltage gradually drops.
  • the last delay drive sub-circuit 4031 is turned on, the a terminal of Pockels box 3 is grounded, and the b terminal is still a ⁇ / 4 wave voltage.
  • the interval time of different delay signals you can adjust the speed of voltage drop across the voltage dividing capacitor 4022 in the decompression sub-circuit 4022.
  • the b terminal potential of the Pockels box 3 is always 0V, and the voltage at the a terminal gradually decreases, so that the voltage loaded across the Pockels box 3 gradually decreases, which can realize the Laser output.
  • the electro-optic Q-switch assembly does not control the loss of the optical resonator, that is, the non-Q switch.
  • the controller 14 does not issue a control signal, the high-voltage switch 4012 is turned off, the b end of the Pockels cell 3 is grounded, and the a end is still connected with a ⁇ / 4 wave voltage, and the optical resonator is free In the oscillating state, the static laser as shown in Fig.
  • the high-voltage source is disconnected from the power supply through the control system, so that the output of the two external high-voltage sources is 0, the general The voltage across the Kerr box 3 is 0V, and it can still output the static laser output from the pressurized Q-switched driving circuit shown in FIG.
  • the electro-optic Q-switch assembly When it is necessary to change the pulse energy of the sub-pulse laser immediately after the dynamic laser, it is only necessary to change the opening delay of the electro-optic Q-switch assembly. Turn on the electro-optic Q-switch assembly in advance, because the xenon lamp continues to be pumped, the subsequent sub-pulse laser energy will increase. After the electro-optical Q-switch assembly is turned on, the energy of the subsequent sub-pulse laser will be reduced because the pumping of the xenon lamp is almost completed. As shown in FIG. 8, the Q-switch dynamic laser in the invention is followed by the sub-pulse laser waveform. .

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Abstract

一种电光Q开关双频双脉冲激光碎石系统，包括全反射镜(1)、电光调Q开关组件、驱动电路(4)、控制器(14)、泵浦源(13)、增益介质(6)、输出镜(7)、第一聚焦镜(8)、倍频晶体(12)、第二聚焦镜(9)、耦合透镜(10)和输出光纤(11)；电光调Q开关组件和增益介质(6)位于全反射镜(1)和输出镜(7)之间；控制器(14)控制泵浦源(13)工作、通过控制驱动电路(4)控制电光调Q开关组件上的电压，使系统输出脉宽为1μs～1.5μs或200μs～300μs的双频激光光束。该系统能粉碎尺寸较大的结石、也能实现结石周围软组织切割、电光效率高且易于更改脉宽，适合临床的使用。

Description

电光Q开关双频双脉冲激光碎石系统
本发明要求于2018年11月20日提交中国专利局、申请号为201811381556.4、发明名称“电光Q开关双频双脉冲激光碎石系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及光基医疗器械技术领域，具体涉及电光Q开关双频双脉冲激光碎石系统。
背景技术
为了粉碎消化系统和泌尿系统结石，人类发明了如体外震波碎石、液电碎石、超声碎石、激光碎石等多种方法。由于激光碎石有许多固有的优点，在临床上除了对肾结石首选体外震波，其他方法基本被激光碎石所取代。而在激光碎石的方法中，目前临床采用的是Ho:Cr:Tm:YAG 2.1微米静态激光和Nd:YAG 1.064+0.532微米双频双脉冲Q开关激光。
上述两种激光碎石机具有完全不同的作用机理。Q开关双频双脉冲Nd:YAG激光的碎石作用是结石在接受高功率密度的激光照射后，其表面挥发出的原子被高能激光光子电离，并迅速形成等离子体，等离子体继而吸收后续的激光能量，迅速膨胀和坍塌，产生的冲击波和微喷射即可破碎结石。而钬激光则主要是靠水和结石吸收极大的激光能量，产生热钻孔和热爆破。相比于应用较为广泛的钬激光碎石系统，采用Q开关Nd:YAG激光仅采用较小的能量(100mJ左右)即可实现高峰值功率(1×10 5W左右)，即使对着输尿管壁打1000个脉冲，对这些软组织不会造成损伤。钬激光碎石通常能量高达1000-3000mJ左右，而峰值功率却仅有1×10 4W，因此通常情况下，一旦光纤对不准结石而打在输尿管壁上，一个脉冲足以造成管壁的穿孔。因此目前国内能够生产的钬激光碎石机仅能用于粉碎尺寸较大的结石，而对于微小的结石的效果不佳，而且危险性较大。
在现有技术中公开了一种Q开关Nd：YAG激光碎石系统(U-100和U-100Plus，后者是前者的升级版)，如图1所示，光路内部采用20-30米长的光纤，用于延长激光谐振腔的长度，同时采用被动调Q晶体压缩激光脉宽，最终实现1μs的激光脉冲输出。但这种结构存在以下缺点：一是若要改变输出的脉宽，需更换光路内部的光纤长度，这就需要对系统进行复杂的重调，在临床使用中是做不到的；二是结构中采用被动调Q晶体实现1μs激光的输出，由于被动调Q的谐振腔损耗很高，因此整机的电光效率较低；三是这种结构由于使用了长光纤和Cr4+:YAG被动调Q，只能输出1μs的动态碎石脉冲。但实际临床使用中往往遇到在结石外围包裹一层软组织结构，在碎石之前必须先将软组织汽化剥离，该碎石机是做不到的。
因此，缺少一种能粉碎结石、也能实现结石周围软组织切割、且电光效率高、易于更改脉宽的激光碎石系统。
发明内容
为了解决上述问题，本发明提供一种电光Q开关双频双脉冲激光碎石系统。
本发明为解决技术问题所采用的技术方案如下：
电光Q开关双频双脉冲激光碎石系统，包括全反射镜、电光调Q开关组件、驱动电路、控制器、泵浦源、增益介质、输出镜、第一聚焦镜、倍频晶体、第二聚焦镜、耦合透镜和输出光纤；所述电光调Q开关组件和增益介质位于全反射镜和输出镜之间；所述驱动电路连接电光调Q开关组件；所述控制器连接电光调Q开关组件和泵浦源，控制器控制泵浦源工作，控制器通过控制驱动电路控制电光调Q开关组件上的电压；
控制器控制泵浦源产生泵浦光照射增益介质，控制器控制驱动电路，当电光调Q开关组件上存在电压差时，全反射镜和输出镜之间构成光学谐 振腔，当泵浦光经过光学谐振腔增益达到阈值时通过输出镜输出激光光束，激光光束依次经第一聚焦镜汇聚、经倍频晶体部分倍频、经第二聚焦镜后平行出射、经耦合透镜汇聚耦合、经输出光纤输出，所述激光光束为1μs～1.5μs脉宽的动态激光光束或200μs～300μs脉宽的静态激光光束。
进一步地，当所述电光调Q开关组件上的电压逐渐升高或降低、电光调Q开关组件的损耗逐渐减小且电光调Q开关组件的损耗一直与增益介质的增益保持动态平衡时，输出镜输出脉宽为1μs～1.5μs的激光光束，当电光调Q开关组件上的电压为λ/4时，输出镜输出脉宽为200μs～300μs的激光光束，λ表示输出镜输出的激光光束的波长。
进一步地，所述电光调Q开关组件包括普克尔盒和偏振片，所述驱动电路连接普克尔盒的两端。
进一步地，所述电光调Q开关组件还包括四分之一波片，所述四分之一波片位于全反射镜和普克尔盒之间，当所述普克尔盒两端的电压逐渐降低、普克尔盒的损耗逐渐减小且普克尔盒的损耗一直与增益介质的增益保持动态平衡时，输出脉宽为1μs～1.5μs的激光光束。
进一步地，所述驱动电路包括连接控制器的整形电路、连接整形电路的延时驱动电路、连接延时驱动电路和普克尔盒一端的退压电路、连接普克尔盒另一端的恒压电路，所述退压电路包括依次串联的第二直流高压电源、N个退压子电路和第二接地端，第二直流高压电源与N个退压子电路串联，所述延时驱动电路包括N个延时驱动子电路，延时驱动子电路和退压子电路一一对应连接，N≥3。
进一步地，所述恒压电路为包括第一接地端。
进一步地，所述恒压电路还包括第一直流高压电源、与第一直流高压电源输出端相连的高压开关、与高压开关相连的滤波电路，所述第一接地端与滤波电路相连。
进一步地，所述滤波电路由并联的电容及电阻组成。
进一步地，所述退压子电路包括依次连接的分压MOS开关、分压电容与放电限流电阻，所述分压MOS开关连接对应的延时驱动子电路。
进一步地，所述泵浦源为氙灯，所述增益介质为Nd:YAG晶体。
本发明的有益效果是：
1、通过控制器控制驱动电路和泵浦源，使光学谐振腔能够输出脉宽为1μs～1.5μs的激光光束，也能够输出脉宽为200μs～300μs的激光光束。通过本发明输出的1μs～1.5μs的动态激光光束能实现结石的粉碎，通过输出的200μs-300μs脉宽的静态激光光束能实现结石周围软组织的切割。
2、不同脉宽的激光的切换不需要复杂的更换光路内部光纤，仅通过控制器控制驱动电路开关、驱动电路开关控制电光调Q开关组件上的电压便可实现，无需复杂的重调光路，脉宽更改容易，结构简单，使用方便，适合临床的使用。
3、在光学谐振腔中采用电光调Q组件实现1μs～1.5μs脉宽的激光的输出，降低谐振腔的损耗即降低阈值，提高了电光效率。
4、本发明通过一个光路系统实现两种波长激光的输出，短波激光具有更高的光子能量，有利于等离子体的点火，长波能量被等离子体吸收，增强碎石力度，两种不同波长的激光适用于碎石的不同阶段，且均能够达到良好的碎石效果。
5、使用本发明的电光Q开关双频双脉冲激光碎石系统，通过在主脉冲激光光束后紧跟子脉冲激光光束输出的方式，由于这些子脉冲激光能量被已产生的等离子体吸收后，会极大增强冲击波碎石的强度，所以本发明对以前的碎石机打不开的白而硬的胱氨酸结石都可以粉碎。
附图说明
图1为德国WOM公司U-100激光碎石系统结构图。
图2为本发明加压式调Q光路原理图。
图3为加压式调Q驱动电路原理图。
图4为传统快开关电光调Q氙灯灯光波形、光学谐振腔损耗及激光强度波形图。
图5为慢开关加压式调Q驱动电路控制输出激光机理示意图。
图6为慢开关加压式调Q驱动电路控制输出单一脉冲激光示意图。
图7为用于剥脱软组织的静态激光波形图。
图8为动态激光后紧跟子脉冲激光波形图。
图中：1、全反射镜，2、四分之一波片，3、普克尔盒，4、驱动电路，4011、第一直流高压电源，4012，高压开关、4013、滤波电路，402、退压电路，4021、第二直流高压电源，4022、退压子电路，403、延时驱动电路，4031、延时驱动子电路，404、整形电路，5、偏振片，6、固体激光棒，7、输出镜，8、第一聚焦镜，9、第二聚焦镜，10、耦合透镜，11、输出光纤，12、倍频晶体，13、泵浦源，14、控制器。
具体实施方式
为了能够更清楚地理解本发明的上述目的、特征和优点，下面结合附图和具体实施方式对本发明进行进一步的详细描述。
在下面的描述中阐述了很多具体细节以便于充分理解本发明，但是，本发明还可以采用其他不同于在此描述的其他方式来实施，因此，本发明的保护范围并不受下面公开的具体实施例的限制。
电光Q开关双频双脉冲激光碎石系统，包括全反射镜1、电光调Q开关组件、驱动电路4、控制器14、泵浦源13、增益介质6、输出镜7、第一聚焦镜8、倍频晶体12、第二聚焦镜9、耦合透镜10和输出光纤11。 如图2所示，电光调Q开关组件和增益介质6位于全反射镜1和输出镜7之间。驱动电路4连接电光调Q开关组件，控制电光调Q开关组件的打开与关闭。控制器14连接电光调Q开关组件和泵浦源13，控制器14控制泵浦源13工作，控制器14控制驱动电路4、通过驱动电路4控制作用在电光调Q开关组件上电压。
控制器14控制泵浦源13开始泵浦，泵浦源13产生泵浦光照射增益介质6，控制器14控制驱动电路4，当驱动电路4施加在电光调Q开关组件上的电压存在电压差时，全反射镜1和输出镜7之间构成光学谐振腔，当泵浦光经过光学谐振腔增益达到阈值时，通过输出镜7输出激光光束，此时输出镜7输出的激光光束为1μs～1.5μs脉宽的激光光束或200μs～300μs脉宽的激光光束。从输出镜7输出的激光光束经第一聚焦镜8汇聚后入射到倍频晶体12上，经倍频晶体12部分倍频(由于倍频晶体12均具有倍频效率，所以一部分激光光束倍频、另一部分频率不变)入射到第二聚焦镜9、经第二聚焦镜9后平行出射到耦合透镜10上，经耦合透镜10汇聚耦合后传输到输出光纤11中，经输出光纤11输出系统，进行医学治疗。输出镜7输出激光光束经倍频晶体12使得1μs～1.5μs脉宽的激光光束或200μs～300μs脉宽的激光光束变成双频激光光束输出。
本发明的电光Q开关双频双脉冲激光碎石系统通过控制器14控制驱动电路4和泵浦源13，使光学谐振腔能够输出脉宽为1μs～1.5μs的动态激光光束，该脉宽的动态激光光束能够粉碎结石；通过控制器14的控制使光学谐振腔能够输出脉宽为200μs～300μs的静态激光光束，该脉宽的静态激光光束能够实现结石周围软组织的切割，因此采用本发明的激光碎石系统不仅可以实现结石的粉碎，而且能够用于去除结石周围软组织。同时输出光纤11一旦没有对准结石，也不会对造成人体伤害，如输出光纤11一旦打在输尿管壁上也不会造成管壁穿孔，安全性高。另外，光学谐振 腔内没有采用输出光纤11，不同脉宽的激光的切换不需要复杂的更换光路内部输出光纤11，仅仅通过控制器14控制驱动电路4、驱动电路4控制电光调Q开关组件便可实现，无需复杂的重调光路，脉宽更改容易，适合临床的使用。在光学谐振腔中采用电光调Q组件(主动电光Q开关)实现1μs～1.5μs脉宽的动态激光光束的输出，降低谐振腔的损耗即降低阈值，提高了电光效率。本发明通过一个光路系统实现两种波长激光的输出，短波激光具有更高的光子能量，有利于等离子体的点火，长波能量被等离子体吸收，增强碎石力度，且均能够达到良好的碎石效果。使用本发明的电光Q开关双频双脉冲激光碎石系统，通过在主脉冲激光光束后紧跟子脉冲激光输出的方式，由于这些子脉冲激光能量被已产生的等离子体吸收后，会极大增强冲击波碎石的强度，所以本发明对以前的碎石机打不开的白而硬的胱氨酸结石都可以粉碎。本发明具有技术上完全自主创新，功能上超过具有世界先进水平的激光碎石系统，本发明是一种能粉碎尺寸较大的结石、能切割结石周围软组织、具有碎石效果好、碎石能力强、能量转换高效、易于更改脉宽、结构简单、使用方便等诸多优点的高水平医疗系统。
控制器14通过控制驱动电路4使施加在电光调Q开关组件上的电压逐渐升高或降低、电光调Q开关组件的损耗逐渐减小且电光调Q开关组件的损耗与增益介质的增益保持动态平衡时，此时光学谐振腔(可简称谐振腔)内始终维持基本稳定的激光振荡，输出镜7能够输出脉宽为1μs～1.5μs的激光光束。控制器14通过控制驱动电路4使电光调Q开关组件上的电压为λ/4时，输出脉宽为200μs～300μs的激光光束，λ表示输出镜7输出的激光光束的波长，即光学谐振腔输出的激光光束的波长。
图2为加压式调Q光路，电光调Q开关组件包括普克尔盒3、偏振片5和四分之一波片2，四分之一波片2、普克尔盒3和偏振片5依次设置在全反射镜1和增益介质之间，对应的驱动电路4称为加压式调Q驱动电路。 若电光调Q开关组件不包括四分之一波片2，则为退压式调Q光路，对应的电路称为退压式调Q驱动电路。驱动电路4连接普克尔盒3的两端。
本实施方式中，增益介质为固体激光棒6，具体采用Nd:YAG晶体，泵浦源13采用氙灯，即输出1064nm激光，1064nm激光经倍频晶体12倍频后，得到532nm的激光。倍频晶体12采用KDP晶体，第一聚焦镜8的用于增强倍频效率，本实施方式输出波长为1064nm激光能量约占总能量的80％，波长532nm激光能量约占总能量的20％。
图3为加压式调Q驱动电路原理图，驱动电路4包括整形电路404、延时驱动电路403、退压电路402和恒压电路。普克尔盒3的两端加载在退压电路402和恒压电路输出端a、b两点之间。恒压电路由第一直流高压电源4011、与第一直流高压电源4011输出端相连的高压开关4012、与高压开关4012相连的滤波电路4013以及与滤波电路4013相连的第一接地端组成，其中滤波电路4013由并联的电容及电阻组成。退压电路402包括第二直流高压电源4021、与第二直流高压电源4021输出端相连的多级串联N个退压子电路4022、第二接地端，顺次连接的分压电容、放电限流电阻与分压MOS开关组成退压子电路4022，即第二直流高压电源4021、分压电容和第二接地端串联，退压子电路4022的数量至少为3个。每个分压MOS开关的栅极作为退压子电路4022的控制端，受到触发电路(触发电路由信号源、整形电路404和延时驱动电路403共同构成触发电路组成)输出的多个延时信号所控制。
图3中“信号源”为控制器14输出的控制信号。信号源为控制器14输出的控制信号，由于控制器14提供的信号属于弱信号，同时控制信号的幅值、时间等参数不能直接驱动后面的延时驱动电路403，因此需要进行处理，控制信号通过整形电路404后变为延时驱动电路403可使用的信号，经延时驱动电路403的第一延时驱动子电路4031输出的第一延时驱 动信号加载在第一分压MOS开关上以后，形成第一级RC放电回路，对应的第一分压电容两端的电压就会下降；延时驱动电路403中的第二延时驱动子电路4031输出的第二延时驱动信号加载在第二分压MOS开关上以后，形成第二级RC放电回路，对应的第二分压电容两端的电压就会下降；依此，驱动电路4中的第三延时驱动子电路4031输出的第三延时驱动信号和后面的延时驱动子电路4031分别延时后依次作用在相应的分压MOS开关上，过程同上。延时驱动电路403依次打开退压子电路4022后，退压电路402的输出端a点电位逐渐降低，而由于恒压电路的输出端b点保持高电位不变，因此普克尔盒3两端的电压逐渐上升，此种方式为加压式电光调Q(即加压式调Q)。由于普克尔盒3连通a和b，则a点既是退压电路402的输出端又是普克尔盒3的变压端，b点既是恒压电路的输出端又是普克尔盒3的恒压端。此处也可用退压方式光电调Q实现，若用退压方式电光调Q(即退压式调Q)，则将图3中普克尔盒3的恒压端b点直接接地即可，也就是恒压电路为仅包括第一接地端，这样由于退压电路402依次被打开，则普克尔盒3变压端a点电位逐渐降低，而恒压端电位始终为0，因此普克尔盒3两端电压依然呈下降趋势，实现了退压式电光调Q。每个延时驱动子电路4031的延时驱动信号对应的退压子电路4022，延时驱动子电路4031与退压子电路4022数量相同，上述将每个延时驱动子电路4031及其发出的延时驱动信号、每个退压子电路4022及其内部的元件均用“第一”、“第二”、“第三”等命名，仅为示意性的顺序区分和元件区分。
根据激光技术常识，常规电光Q开关/电光调Q开关组件是一种快开关，输出的激光脉宽通常为纳秒量级，如图4所示的传统快开关电光调Q加压式电路输出的氙灯灯光波形(灯电流)、光学谐振腔损耗及激光强度波形图，灯光波形随时间呈平顶分布，t 0时刻氙灯放电电流开始下降，光学谐振腔损耗中的损耗迅速减小，光学谐振腔损耗内增益大于光学谐振腔 损耗，从而产生一个大能量、窄脉宽的光脉冲。
为了实现连续1μs量级激光输出，就要使普克尔盒3上的电压升高(或下降)既不能太快，也不能太慢，且电光调Q开关组件的损耗与增益介质的增益保持动态平衡，使腔内始终维持基本稳定的激光振荡，直至达到1μs左右的激光输出。实现连续1μs量级激光输出需要普克尔盒3上电压升高(或下降)的速度适宜，以及在固体激光棒6储能降低或提高时，升压(或下降)的速度也要相应改变。本发明中将普克尔盒3一端加载在多级串联退压电路402输出端，另一端加载在恒压电路输出端，通过外部控制信号依次打开退压电路402，使得退压电路402两端电压逐渐降压，最终普克尔盒3两端电压逐级上升(或下降)。退压子电路4022中的放电限流电阻决定串联的退压子电路4022中每级降压速度，延时驱动子电路4031控制退压的延时，即退压电路402每级降压速度可控、不同级联的退压延时可调。通过控制器14和驱动电路4的控制，使得达到激光振荡基本稳定，最终实现1～1.5微秒平缓输出，顶部振荡峰值小于总幅度的10％以内。
实现办法及原理如下：
应用图3中所示的加压式调Q驱动电路，采用减慢开关速度的办法，来达到输出激光脉宽为1μs量级。激光产生机理如图5慢开关加压式调Q驱动电路控制输出激光机理示意图所示，由图5中可看出，0-t 0时间内，氙灯泵浦固体激光棒6，固体激光棒6中上能级反转粒子数不断增加，普克尔盒3两端电压为零，光学谐振腔损耗很高，固体激光棒6储能，不发射激光；t 0—t 1时间内，普克尔盒3两端电压逐步升高，光学谐振腔损耗小于增益，光学谐振腔内开始输出激光，上能级反转粒子数被部分消耗，当增益小于损耗时，振荡停止，输出第一个光脉冲。t 1—t 2时间内，使普克尔盒3两端电压再次缓慢升高，光学谐振腔损耗进一步减小，增益大于 损耗，部分反转粒子数继续被消耗，光学谐振腔内再次振荡，这样便产生了第二个脉冲，以此类推最终可产生多个光脉冲。输出光脉冲的数量与普克尔盒3两端电压上升的次数相同，每个光脉冲的宽度与电压上升的幅度和电压上升的速度有关。退压式调Q驱动电路对应出光机理同加压式相同。
图6为慢开关加压式调Q驱动电路控制输出单一脉冲激光示意图，为了获得1μs左右光滑光脉冲，分压MOS开关触发延时相对于图5做出适当调节，即通过改变打开前后两个分压MOS开关的控制信号的延时时间，来改变前后两个级联电路放电时刻之间的间隔，如t 0与t 1之间、t 1与t 2时刻之间的间隔，从而增加普克尔盒3两端电压上升速度，即调节光学谐振腔损耗下降速度，最终将几个不同光脉冲之间相互叠加，整合为一个脉宽为1μs左右的光脉冲进行输出。
在退压方式电光调Q中，普克尔盒3两端电压与加压式调Q驱动电路的输出波形(普克尔盒3两端电压)正好相反，而光学谐振腔损耗、激光强度随时间变化波形与之相同。
上述的图4～6均为示意性的表示随时间变化的关系，因此纵坐标没有给出具体单位。
本发明的碎石系统在应用时，会应用到如下几种情况：
1、需要输出Q开关动态激光碎石时
加压式调Q驱动电路：当需要输出Q开关动态激光碎石时，控制器14控制点燃脉冲氙灯并给普克尔盒3的a端、b端同时加上λ/4波(约3400V)的高压，普克尔盒3两端电压差为0，由于四分之一波片2的存在，此时谐振腔关闭，固体激光棒6储能。经约300微秒延时后，控制器14发出控制信号逐级依次打开延时驱动子电路4031，各退压子电路4022上分压电容上电压依次退压，普克尔盒3的a端电压逐渐下降，最后一个延时驱动子电路4031打开后，普克尔盒3的a端接地，b端依然为λ/4波电压， 在此过程中普克尔盒3两端的电压差持续缓慢上升，调节不同延时信号的间隔时间，就可以调节退压子电路4022中分压电容两端电压的下降速度。
退压式调Q驱动电路：普克尔盒3的b端电位始终为0V，a端电压逐渐下降，这样加载在普克尔盒3两端的电压逐步下降，可实现退压式调Q光路的激光输出。
2、需要输出静态激光碎石时
此时即电光调Q开关组件不控制光学谐振腔的损耗，即非Q开关。对于加压式调Q驱动电路，控制器14不发出控制信号，高压开关4012断开，普克尔盒3的b端接地，a端依然接有λ/4波电压，光学谐振腔内处于自由振荡状态，输出如图7所示的静态激光，用于实现剥离软组织；对于退压式调Q驱动电路，通过控制系统断开高压源供电，使外接的两个高压源输出均为0，普克尔盒3两端电压为0V，依然可输出图7中所示的加压式调Q驱动电路输出的静态激光。
3、需改变动态激光后的紧跟子脉冲激光脉冲能量时
当需改变动态激光后的紧跟子脉冲激光脉冲能量时，只需改变电光调Q开关组件打开的延时即可。提前打开电光调Q开关组件，由于氙灯继续在泵浦，后续的子脉冲激光能量就会增加。后延打开电光调Q开关组件，后面由于氙灯泵浦几近结束，后续的子脉冲激光能量就会减小，如图8所示的本发明中Q开关动态激光后紧跟子脉冲激光波形图。

Claims (10)

  1. 电光Q开关双频双脉冲激光碎石系统，其特征在于，包括全反射镜(1)、电光调Q开关组件、驱动电路(4)、控制器(14)、泵浦源(13)、增益介质(6)、输出镜(7)、第一聚焦镜(8)、倍频晶体(12)、第二聚焦镜(9)、耦合透镜(10)和输出光纤(11)；所述电光调Q开关组件和增益介质(6)位于全反射镜(1)和输出镜(7)之间；所述驱动电路(4)连接电光调Q开关组件；所述控制器(14)连接电光调Q开关组件和泵浦源(13)，控制器(14)控制泵浦源(13)工作，控制器(14)通过控制驱动电路(4)控制电光调Q开关组件上的电压；
    控制器(14)控制泵浦源(13)产生泵浦光照射增益介质(6)，控制器(14)控制驱动电路(4)，当电光调Q开关组件上存在电压差时，全反射镜(1)和输出镜(7)之间构成光学谐振腔，当泵浦光经过光学谐振腔增益达到阈值时通过输出镜(7)输出激光光束，激光光束依次经第一聚焦镜(8)汇聚、经倍频晶体(12)部分倍频、经第二聚焦镜(9)后平行出射、经耦合透镜(10)汇聚耦合、经输出光纤(11)输出，所述激光光束为1μs～1.5μs脉宽的动态激光光束或200μs～300μs脉宽的静态激光光束。
  2. 如权利要求1所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，当所述电光调Q开关组件上的电压逐渐升高或降低、电光调Q开关组件的损耗逐渐减小且电光调Q开关组件的损耗一直与增益介质(6)的增益保持动态平衡时，输出镜(7)输出脉宽为1μs～1.5μs的激光光束，当电光调Q开关组件上的电压为λ/4时，输出镜(7)输出脉宽为200μs～300μs的激光光束，λ表示输出镜(7)输出的激光光束的波长。
  3. 如权利要求1所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述电光调Q开关组件包括普克尔盒(3)和偏振片(5)，所述驱动电路(4)连接普克尔盒(3)的两端。
  4. 如权利要求3所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述电光调Q开关组件还包括四分之一波片(2)，所述四 分之一波片(2)位于全反射镜(1)和普克尔盒(3)之间，当所述普克尔盒(3)两端的电压逐渐降低、普克尔盒(3)的损耗逐渐减小且普克尔盒(3)的损耗一直与增益介质(6)的增益保持动态平衡时，输出脉宽为1μs～1.5μs的激光光束。
  5. 如权利要求3所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述驱动电路(4)包括连接控制器(14)的整形电路(404)、连接整形电路(404)的延时驱动电路(403)、连接延时驱动电路(403)和普克尔盒(3)一端的退压电路(402)、连接普克尔盒(3)另一端的恒压电路，所述退压电路(402)包括依次串联的第二直流高压电源(4021)、N个退压子电路(4022)和第二接地端，第二直流高压电源(4021)与N个退压子电路(4022)串联，所述延时驱动电路(403)包括N个延时驱动子电路(4031)，延时驱动子电路(4031)和退压子电路(4022)一一对应连接，N≥3。
  6. 如权利要求5所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述恒压电路为包括第一接地端。
  7. 如权利要求6所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述恒压电路还包括第一直流高压电源(4011)、与第一直流高压电源(4011)输出端相连的高压开关(4012)、与高压开关(4012)相连的滤波电路(4013)，所述第一接地端与滤波电路(4013)相连。
  8. 如权利要求7所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述滤波电路(4013)由并联的电容及电阻组成。
  9. 如权利要求5所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述退压子电路(4022)包括依次连接的分压MOS开关、分压电容与放电限流电阻，所述分压MOS开关连接对应的延时驱动子电路(4031)。
  10. 如权利要求1所述的电光Q开关双频双脉冲激光碎石系统，其特征在于，所述泵浦源(13)为氙灯，所述增益介质(6)为Nd:YAG晶体。
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