KR200417038Y1 - Power supply for laser - Google Patents

Abstract

The present invention relates to a power supply device for a pulsed laser, and more particularly to a laser for use in medical applications relates to a power supply device that can control the pulse energy and pulse width.

Power supply device for a pulsed laser of the present invention is a power supply; A capacitor that receives power from the power supply unit and is charged with a constant voltage and discharges the discharge; an inductor for converting the voltage discharged from the capacitor into a pulse current and supplying the flash lamp; and a first to interrupt the discharge of the capacitor. A plurality of PFN units including a switch and connected in parallel to each other; And a controller for controlling ON / OFF of each switch of the plurality of PFN units to control pulse width and pulse energy supplied to the flash lamp.

Pulse, Superposition, Pulse Width, Pulse Energy, PFN, Flash Lamp, Switch

Description

Power supply for pulsed lasers {POWER SUPPLY FOR LASER}

1 and 2 are circuit diagrams of a conventional laser power supply device.

3 and 4 is a circuit diagram of a power supply device for a laser according to the present invention.

5 and 6 is a view for explaining the pulse energy and pulse width control by the overlap according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: PFN part

20: power supply

30: Simmer Driver

40: flash lamp

50: control unit

The present invention relates to a power supply device for a pulsed laser, and more particularly to a laser for use in medical applications relates to a power supply device that can control the pulse energy and pulse width.

Lasers have a wide range of applications, including industrial, processing, medical, military, and measurement. In particular, it is recognized that there is little pain in the medical field, and that it is easy to use and has great competitiveness.

Pulsed lasers must be capable of generating pulse shapes suitable for their intended use. That is, it is necessary to adjust the pulse width or to adjust the pulse energy (pulse amplitude) according to the purpose of use.

1 and 2 show a power supply for a conventional pulsed laser, Figure 1 is a conventional power supply for a conventional laser, Figure 2 is a power supply for a laser that can adjust the pulse width.

First, operation of the laser power supply device will be briefly described with reference to FIG. When the voltage output from the power supply unit 2 is charged in the capacitor C of the pulse forming network (PFN) unit 1 and the switching element SCR is conducted after the charging is completed, the voltage charged in the capacitor C When discharged, a pulsed current is applied to the flash lamp 4 through the inductor L, and the flash lamp 4 generates a laser beam. The pulse energy (i.e., amplitude magnitude of the pulse) is controlled by the voltage regulation output from the power supply 2 (i.e., charged to the capacitor).

In the laser power supply of FIG. 1, the capacitance value of the capacitor C and the inductance value of the inductor L are fixed, so that the current applied to the flash lamp 4 is constant regardless of the voltage charged in the capacitor C. It has a pulse width. Therefore, there is a problem that can not be used in plastic surgery, dermatology and the like that need to adjust the pulse width. Thus, proposed by the necessity of adjusting the pulse width is the power supply device for the laser of FIG.

In the laser power supply of FIG. 2, the pulse duration is controlled by controlling the discharge duration of the capacitor C by the transistor IGBT whose ON / OFF is controlled by the driver after charging a large voltage to the large capacitor C. Adjust

2 shows that the pulse shape of the current applied to the flash lamp 4 forms a square wave. Therefore, harmonics are present in the pulse, and the beam phenomenon generated from the oscillator has a serious adverse effect on the beam transmitting apparatus such as fiber. For reference, when the pulse applied to the flash lamp 4 becomes the most stable laser beam when forming the Gaussian waveform, the pulse can be most stably transmitted to the peripheral beam transmitter.

In addition, the driver and the transistor IGBT of FIG. 2 are not only complicated and expensive in construction, but also have a very high magnitude of current (hundreds of A) flowing through the transistor IGBT, which may cause significant voltage stress on the transistor IGBT and break it. high. If the transistor IGBT is damaged and kept in the conducting state, all the energy stored in the capacitor C is discharged to the flash lamp 4, in which a significant amount of laser is generated, which may cause fatal damage to the patient during treatment.

In addition, the laser pulse energy is achieved by adjusting the output voltage of the power supply unit 2. For this purpose, the conventional power supply unit 2 adjusts the primary side voltage of the transformer by an inverter method using a semiconductor switching element to output the secondary side. A method of controlling the output voltage of the secondary side or the PWM method of controlling the voltage or adjusting the pulse width of the primary side voltage was used. This conventional power supply has a problem that the configuration is complicated and expensive.

The present invention has been made to solve the above-mentioned conventional problems, and can independently control the pulse width and the pulse energy in the PFN unit irrespective of the power supply unit, and use a low-cost switching element for the adjustment, and the flash The form of the pulse applied to the lamp aims to provide a power supply for a pulsed laser which forms a Gaussian wave.

It is also an object of the present invention to provide a power supply device for a pulsed laser capable of adjusting a multilevel voltage level by a simple structure.

The power supply device for a pulsed laser of the present invention for achieving the above object

A power supply unit;

A capacitor that receives power from the power supply unit and is charged with a constant voltage and discharges the discharge; an inductor for converting the voltage discharged from the capacitor into a pulse current and supplying the flash lamp; and a first to interrupt the discharge of the capacitor. A plurality of PFN units including a switch and connected in parallel to each other;

And a controller for controlling ON / OFF of each switch of the plurality of PFN units to control pulse width and pulse energy supplied to the flash lamp.

The power supply unit may include a plurality of transformers sharing a primary coil, a rectifying means connected to secondary coils of each of the plurality of transformers, and a plurality of transformers respectively or a series connection combination to an output terminal. It characterized in that it comprises a voltage level adjusting means for adjusting the level of the voltage charged in the capacitor.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a circuit diagram of a power supply device for laser according to the present invention, and FIG. 4 is a circuit diagram of a power supply unit.

The shimmer driver 30 shown in FIG. 3 supplies several tens of kV for the initial lighting of the flash lamp 40, and after lighting, the minimum DC current (called the shimmer current) for continuously maintaining the lighting state ( 0.1-1 A). The flashlamp 40 generates a laser by a pulse current applied from the PFN unit 10.

The PFN units 10:11 to 1n are configured with an LC parallel circuit to output a pulse current of Gaussian wave form. Referring to FIG. 3, the capacitors C1 to Cn connected in parallel to the power supply unit 20 and the inductors L1 to Ln connected in parallel to the capacitors C1 to Cn and connected to the flash lamp 40 in series. A first switch SCR1 to SCRn disposed between the capacitors C1 to Cn and the inductors L1 to Ln to interrupt the discharge of the capacitors C1 to Cn, and the capacitors C1 to Cn and the power supply unit. It is disposed between the (20) and comprises a second switch (Q1 ~ Qn) for controlling the charge to the capacitor (C1 ~ Cn).

The PFN unit 10 has a plurality of 11 to 1n connected in parallel, and the first switch SCR1 to SCRn and the second switch Q1 to Qn of each PFN unit 11 to 1n are connected to the control unit 50. ON / OFF is controlled by

The PFN unit 10 configured as described above controls pulse energy and pulse width through superposition of pulses.

The pulse energy is adjusted by simultaneously turning on the first switches SCR1 to SCRn to suit the desired energy intensity, and the pulse width is adjusted by sequentially turning on the first switches SCR1 to SCRn to the desired width. All.

As an example, first, the two second switches Q1 and Q2 of the first and second PFN units 11 and 12 are turned on to charge the two capacitors C1 and C2, and after the charging is completed, the controller 50 When two first switches (SCR1, SCR2) are simultaneously conducted with each other, the charging voltage is discharged from each of the capacitors (C1, C2) and a pulse current (I1, I2) is formed through each inductor (L1, L2). Then, the current having the amplitude as shown in Fig. 5 is applied to the flash lamp 40 by the principle of superposition. In the above process, when the two first switches SCR1 and SCR2 are sequentially connected, a current having a width as shown in FIG. 6 is applied to the flash lamp 40 by the principle of superposition.

Here, in order to increase the efficiency of pulse energy and pulse width adjustment by overlapping, the width and amplitude of the currents I1 to In output from the respective PFN units 11 to 1n are preferably the same. Since the amplitude is determined by the capacitance of the capacitor (the magnitude of the voltage to be charged) and the width is determined by the capacitance and inductance of the capacitor and the inductor, it is desirable to equalize the value of each of these capacitances and inductances.

For reference, in FIG. 3, a silicon rectifier is used as the first switches SCR1 to SCRn and a transistor is used as the second switches Q1 to Qn.

The second switches Q1 to Qn charge only the capacitors C1 to Cn necessary for forming desired pulse energy and pulse width, thereby preventing unnecessary power consumption, and after the charging of the capacitors C1 to Cn is completed. By blocking the power supply unit 20, the waveforms of the currents I1 to In output from the PFN unit 10 are kept constant. If the second switches Q1 to Qn are not present, the capacitors C1 to Cn are charged even while the capacitors C1 to Cn are discharged, and thus deformations in the waveforms of the output currents I1 to In are caused. It does not overlap with the desired pulse width or pulse energy, and the superimposed currents (I1 + I2 + ... + In) become unstable.

The power supply unit 20 boosts and rectifies the input AC power to output a DC power to charge the capacitors C1 to Cn of the PFN unit 10 to a multi-level voltage level. The voltage charged to capacitors C1-Cn to generate a laser is 500 volts to 2000 volts. That is, the voltage output from the power supply 20 is 500 to 2000 volts.

As shown in FIG. 4, the power supply unit 20 is connected to a plurality of transformers T1, T2, and T3 sharing a primary coil and secondary coils of each of the transformers T1, T2, and T3. A rectifying means 21 for rectifying the output voltage, and an output voltage (voltage charged in the capacitor) connecting each of the plurality of transformers T1, T2, T3 or a combination thereof to the output terminals V +, V-. It comprises a voltage level adjusting means consisting of a third switch (S1, S2, S3, S4, S5) and diodes (D1, D2, D3, D4) to adjust.

And an offset transformer T0 for sharing the primary coil and supplying an offset voltage Voff to the capacitors C1 to Cn of the PFN unit 10. Here, the offset voltage Voff means a minimum voltage value to be charged in the capacitors C1 to Cn of the PFN unit 10 to generate a laser, and the size of the offset voltage Voff is about 500 volts.

The power supply unit 20 of the present invention used a large number of simple linear transformers (T1, T2, T3) rather than a complicated and expensive inverter or PWM method to adjust the level of the output voltage. In order to output various voltage levels with the minimum number of transformers, the output voltage of each transformer (T1, T2, T3) is k · 2 ^ (n-1) volts. Here, k is the magnitude of the voltage input to the primary coil, n is the order of each of the plurality of transformers (T1, T2, T3). That is, as shown in FIG. 4, when the voltage input to the primary coil is 1 volt, transformer 1 is 1 volt (= 2 ^ 0), transformer 2 is 2 volt (= 2 ^ 1), and number 3 In the transformer, 4 volts (= 2 ^ 2) are each induced in the secondary coil.

In this way, the voltage induced in each of the transformers T1, T2, and T3 is output by being combined with voltages of various magnitudes by the voltage level adjusting means S1 to S5, D1 to D4.

As shown in FIG. 4, the voltage level adjusting means S1 to S5 and D1 to D4 include the (-) stage of the first transformer T1 and the transformers T2 and T3 other than the first transformer T1. Diodes D3 and D4 connecting the stages respectively, and diodes D1 connecting the positive terminals of the nth transformer T3 and the positive terminals of the transformers T1 and T2 other than the nth transformer, respectively. , D2), and third switches S1, S2, S3, S4, and S5 in which the plurality of transformers T1, T2, and T3 are connected in series and controlled ON / OFF by the controller 50. It is done by It is obvious that the diodes D1, D2, D3, and D4 may be replaced by another switch controlled by the controller 50.

The voltage level of various magnitudes can be output to the output terminals V + and V- with reference to FIG. 4, but the offset transformer T0 is always connected to the output terminal and thus omitted and explained. The assumption is made that the voltage being 1 volt as shown.

When the output voltage reaches 1 volt, all of the third switches S1, S2, S3, S4, and S5 are turned OFF, and at this time, the (+) output terminal (V +)-2 diode (D2) -first It becomes a transformer (T1)-(-) output terminal (V-).

When the output voltage reaches 2 volts, only the 5th switch (S5) of the third switch is in the ON state, and the path at this time is the (+) output terminal (V +)-1 diode (D1)-5th switch (S5)- The second transformer T2-the third diode D3-(-) output terminal (V-).

When the output voltage reaches 6 volts, only switches 2 and 3 (S2 and S3) are turned off, and the path is (+) output terminal-switch 4 (S4)-third transformer (T3)-1 Switch (S1)-Switch 5 (S5)-Second transformer (T2)-Diode 3 (D3)-(-) output terminal.

When the output voltage reaches 7 volts, only switch No. 3 (S3) will be in the OFF state, and the path at this time will be (+) The fifth switch (S5)-the second transformer (T2)-the second switch (S2)-the first transformer (T1)-(-) output stage.

When the output voltage reaches 5 volts, switches 3 and 4 are turned on.When the output voltage reaches 4 volts, switch 4 is turned on. When the output voltage reaches 3 volts, switches 2 and 5 are turned on. At this time, the path can be easily understood.

In addition, one of ordinary skill in the art will appreciate that the above-mentioned paths naturally form current paths such that diodes D1, D2, D3, and D4 may have various combinations of outputs due to their characteristics. That is, the diodes D1, D2, D3, and D4 connected in this way may take the role of a switch controlled by the controller 50.

3 and 4, the power supply device for the pulsed laser according to the present invention is simple in the overall circuit configuration. In other words, a circuit configuration can be made by using a low-cost device without using expensive devices, and molding of desired pulse energy and pulse width can be easily performed.

As described above, the present invention forms a Gaussian wave in the form of a pulse applied to a flash lamp, so that the stability is high.

Irrespective of the power supply, the pulse energy and pulse width can be adjusted by superimposing the pulses in the PFN unit, and this adjustment is simply performed by ON / OFF operation of the switch.

Multistage output voltage regulation at the power supply is simply performed by a voltage level adjusting means composed of a plurality of linear transformers, switches and diodes,

The overall circuit configuration can be made of low specification devices, which has the advantage of significantly lowering the manufacturing cost.

In the above description of the subject innovation, a power supply device for a pulsed laser having a specific circuit diagram has been described with reference to the accompanying drawings, but the subject innovation can be variously modified and changed by those skilled in the art. It should be interpreted as falling within the protection scope of.

Claims (6)

A power supply unit; A capacitor that receives power from the power supply unit and is charged with a constant voltage and discharges the discharge; an inductor for converting the voltage discharged from the capacitor into a pulse current and supplying the flash lamp; and a first to interrupt the discharge of the capacitor. A plurality of PFN units including a switch and connected in parallel to each other; Control unit for controlling the pulse width and the pulse energy supplied to the flash lamp by controlling the ON / OFF of each switch of the plurality of PFN unit. The method of claim 1, And a second switch between the power supply unit and the capacitors of the respective PFN units, the second switch being controlled ON / OFF by the control unit. The method according to claim 1 or 2, The power supply unit and a plurality of transformers sharing a primary coil, Rectifying means connected to secondary coils of each of said plurality of transformers; And a voltage level adjusting unit for connecting each of the plurality of transformers or a combination of a series connection to an output terminal to adjust the level of the voltage charged in the capacitor of the PFN unit. The method of claim 3, wherein The voltage supplied to the secondary coil of each of the plurality of transformers is a power supply device for a pulsed laser, characterized in that k · 2 ^ (n-1) volts, Here, k is the magnitude of the voltage input to the primary coil, n is the sequence number of each of the plurality of transformers. The method of claim 4, wherein The voltage level adjusting means of the power supply unit includes a diode connecting the negative terminal of the first transformer and the negative terminal of a transformer other than the first transformer, the positive terminal of the nth transformer, and the other than the nth transformer. Diodes connecting the positive ends of the transformer, and And a third switch in which the plurality of transformers are connected in series, and the ON / OFF is controlled by the control unit. The method of claim 5, wherein The power supply unit further comprises an offset transformer for sharing the primary coil and supplying an offset voltage to the capacitor of the PFN unit.

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