JP2025003103A - Electrical Pulse Generator - Google Patents

Abstract

To provide an apparatus capable of generating, with high reproducibility, a pulse current that exhibits a high current peak in a short period of time.SOLUTION: An electrical pulse generator includes a load circuit section arranged so that an output voltage from a high voltage source can be applied to the load circuit section. The load circuit section has a switching element connected in series to an object to be energized, a capacitor, and a diode, and forms a first closed circuit, which is a series circuit including the capacitor, the object to be energized, and the switching element, when the switching element is in a conductive state. The anode terminal and the cathode terminal of the diode are each connected to two points on the first closed circuit. When the switching element is made to transition from a non-conductive state to a conductive state while the capacitor is in a charged state, the connection point between the cathode terminal and the first closed circuit is arranged electrically closer to the high potential side terminal of the capacitor than the connection point between the anode terminal and the first closed circuit.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electric pulse generator that applies an electric pulse to an object.

Conventionally, a pulse generating circuit has been used as a means for lighting a flash lamp (see, for example, Patent Document 1).

A flash lamp is a lamp that is primarily used as a heating light source, emitting light ranging from the visible to infrared ranges and irradiating an object with this light to heat the object. When a current is supplied to this lamp, the lamp emits an amount of light that corresponds to the waveform of the supplied current. Therefore, by controlling this current waveform, particularly the pulse width, it is possible to control the heating depth of the object. For example, by appropriately controlling the pulse width and peak value of the current waveform, it is possible to heat only the surface of the object while minimizing thermal damage to the object.

The above technology can be applied to heating a substrate in the semiconductor manufacturing process. A substrate is formed by stacking multiple semiconductor and insulating layers on top of a base wafer. For example, when forming a semiconductor layer, an annealing process is performed to diffuse the doped impurities. A flash lamp is used during this annealing process. By appropriately controlling the waveform of the current supplied to the flash lamp, it is possible to selectively heat only the semiconductor layer formed on the surface of the substrate without causing damage to the inside of the substrate.

In recent years, semiconductor products have become increasingly miniaturized and highly integrated. To increase the integration density of semiconductor products, many thin films are stacked. For this reason, there is an increasing demand for technology that can control the heating of only those thin films as the role of the flash lamp. This is because if heating were to occur in areas other than the surface layer, layers formed deeper than the surface would be heated multiple times as layer formation and heating processes are repeated, raising concerns that this could affect the quality of the semiconductor. From this perspective, a method of reducing the pulse width of light emitted from a flash lamp is known as a method of controlling the heating of only the extremely shallow surface of the object to be heated.

The technology of selectively heating the area near the surface of an object can also be applied when recycling layered components.

Electrical appliances such as communication terminal devices and home appliances that are no longer in use may contain usable resources. From the perspective of resource conservation, such electrical appliances that are no longer in use are required to be collected by businesses, disassembled, and recycled. Traditionally, this type of work has often been done by disassembling by hand or physically dismantling using a crusher. However, such work requires a lot of manpower, and the quality of the parts after dismantling tends to be low, which reduces the percentage of items that can be recycled.

Waste that can be recycled includes those in which insulating materials or semiconductors are layered on conductive materials such as metals. More specific examples include composite materials in which an organic material is applied to a metallic material, composite materials in which paint is applied to a metallic material, and composite materials in which an insulating material is attached or vapor-deposited onto a metallic material.

As described above, waste materials made of composite materials including metal materials can be recycled by crushing and burning them, and separating and extracting the necessary metals from the resulting combustion ash. However, this method may result in the metals being denatured into metal compounds or alloys, which requires subsequent processing, and also results in a large amount of _CO2 emissions during combustion, which is problematic in terms of environmental impact. In the case of the wet method, the extracted materials are subjected to chemical processing such as electrolysis, ion exchange, and chemical reaction, but high-purity materials are not separated and recovered from the beginning, which results in a large energy burden.

From the above perspective, a method has been proposed in which a lamp is indirectly used to heat a specific object, and the lighting pulse width of the lamp is shortened to selectively heat the object (Patent Document 1 below). As another example, a method has been proposed in which, rather than indirectly using a lamp, a pulse voltage is directly applied to the object to be recycled to selectively heat and dismantle it (Patent Document 2 below).

JP 2005-197024 A Patent No. 6857363

Patent Document 1 describes that efforts are being made to shorten the lighting pulse width of flash lamps in order to reduce the energy input to the lamp and the power source. It also describes that short-pulse light is required in fields other than semiconductor annealing, such as modifying the surface of ceramic thin films and adhesively fixing optical components by photocuring.

However, Patent Document 1 does not make any detailed mention of short pulses. It is believed that short-term light irradiation of the object, in other words, short-term energy supply, is important in order to prevent the object from having a heating history. Short-term energy supply makes it possible to selectively raise the temperature of only the surface of the object (the side to which energy is supplied). On the other hand, in order to achieve the purpose of surface treatment of the object, etc., it is necessary to supply a sufficient amount of energy. To achieve the desired treatment in a short time, it is necessary to increase the energy per unit time, which may lead to excessive heating of the object and damage to the lamp.

The technology described in Patent Document 2 is to separate the positive metal foil that constitutes the battery from the active material bonded to its surface by passing an appropriate pulse current through the current-carrying object. In other words, in the technology described in Patent Document 2, it is important to control the energy input to the binder, which is the object to be heated, by supplying a high peak current to the object to be current-carrying. This is exactly the same idea as the heating by the lamp mentioned above. However, there are technical difficulties in realizing a power supply device that can reproducibly generate a high pulse current in a short time. Patent Documents 1 and 2 do not disclose a power supply device that can reproducibly generate a high pulse current in a short time.

In view of the above problems, the present invention aims to provide an electric pulse generator that can generate a pulse current with high reproducibility that shows a high current peak in a short time in order to selectively heat the vicinity of the surface of an object to be heated.

The electric pulse generating device according to the present invention is a device for applying an electric pulse to an electric current application object,
a high voltage source and a load circuit section arranged to be able to apply an output voltage from the high voltage source;
The load circuit section includes:
The current passing object;
A switching element connected in series to the current-carrying object;
a capacitor disposed in a position capable of being charged based on an output voltage from the high voltage source when the high voltage source and the load circuit unit are electrically connected;
a diode including an anode terminal and a cathode terminal;
the load circuit unit forms a first closed circuit, which is a series circuit including the capacitor, the current-carrying object, and the switching element, when the switching element is in a conductive state;
the anode terminal and the cathode terminal of the diode are each connected to two points on the first closed circuit,
The present invention is characterized in that, at a point in time when the switching element is transitioned from a non-conducting state to a conducting state while the capacitor is in a charged state, the connection point between the cathode terminal and the first closed circuit is positioned electrically closer to the high potential side terminal of the capacitor than the connection point between the anode terminal and the first closed circuit.

The load circuit section includes a capacitor, a switching element, and a diode. The switching element is connected in series with the object to be energized, and the capacitor is positioned so that it can be charged based on the voltage from the high-voltage source. When the switching element is in a conductive state, the load circuit section forms a series circuit (first closed circuit) that includes the capacitor, the object to be energized, and the switching element.

By connecting the high voltage source to the load circuit with the switching element in a non-conducting state, the capacitor is charged by the voltage from the high voltage source. Then, by electrically disconnecting the high voltage source from the load circuit and making the switching element conductive, a high current derived from the charging voltage of the capacitor is supplied to the object to be energized via the switching element. Since the current flows immediately after the switching element is made conductive, this current exhibits a pulsed shape.

Furthermore, as described above, the load circuit section is provided with a diode. This diode is arranged such that, when the switching element is transitioned from a non-conductive state to a conductive state while the capacitor is in a charged state, the connection point between the cathode terminal and the first closed circuit is electrically closer to the high potential terminal of the capacitor than the connection point between the anode terminal and the first closed circuit. In other words, when the switching element is in a charged state to pass a high current to the current-carrying object, the current derived from the charging voltage of the capacitor flows to the current-carrying object, and then the current bypasses the capacitor and flows through the diode. As a result, after the switching element is turned on, the capacitor does not transition from the charged state of the capacitor immediately before the switching element is turned on to a charged state of reverse polarity. In other words, the flow of an oscillating current whose polarity changes is suppressed in the first closed circuit. This means that the time during which current is supplied to the current-carrying object can be shortened, in other words, the pulse width of the current flowing to the current-carrying object can be shortened.

As a specific example, if a diode is not provided, the current waveform would be an alternating current (AC) with a damped oscillation over a period of several milliseconds, but by adding a diode, this becomes a single pulse, and the overall period of current supply can also be reduced.

The above-mentioned electric pulse generator can be applied to a flash lamp, as an example. The effect of supplying a pulse current to a flash lamp using the electric pulse generator of the present invention will be explained in comparison with the case where a conventional electric pulse generator is used.

Figure 25 is a circuit diagram showing a schematic configuration of a conventional electric pulse generator used to light a flash lamp. As shown in Figure 25, a conventional electric pulse generator 100 includes a high voltage source 95 and a load circuit section to which the voltage generated by the high voltage source 95 is applied. More specifically, this load circuit section is formed of a closed circuit U100 including a capacitor 91, a mechanical switch 92, and an electric current object 90. In this example, the electric current object 90 corresponds to the flash lamp. The mechanical switch 92 is a switch that switches between electric current and non-electric current by mechanical contact, but may be a gap switch.

The switching element 96 shown in FIG. 25 is provided for the purpose of switching the connection state between the high voltage source 95 and the capacitor 91. When the switching element 96 is conductive, the capacitor 91 starts charging with the voltage output from the high voltage source 95. When the charging of the capacitor 91 is completed, the switching element 96 is turned OFF and the mechanical switch 92 is turned ON, so that a high current derived from the charging voltage of the capacitor 91 is supplied to the current-carrying object 90.

However, in the case of the electric pulse generator 100 shown in FIG. 25, an AC current (damped oscillatory current) actually flows through the current-carrying object 90 for a period of several tens of ms to 100 ms. This will be described later in the section "Form for carrying out the invention" with reference to FIG. 8.

In other words, when a pulse current is supplied to the object 90 to be energized using the electric pulse generator 100 shown in FIG. 25, a current that exhibits a damped oscillatory waveform is actually supplied to the object 90 to be energized. This means that when the object 90 to be energized is a flash lamp, the flash lamp irradiates the object to be heated with heating light (light with a wavelength absorbed by the object to be heated) for a certain length (the above-mentioned several tens of ms to 100 ms). As a result, heat energy is supplied not only to the surface layer of the object to be heated, but also in the depth direction. When the object to be heated is a wafer including a semiconductor layer, layers other than the outermost surface are also heated, which may affect the quality of the semiconductor.

Furthermore, if the object 90 to be energized is a flash lamp, passing too high a current may damage the lamp. In order to selectively heat the surface of the object to be heated using a flash lamp, a high peak current may be supplied to the lamp for a short period of time to cause the lamp to discharge and emit light for a short period of time. To achieve this, it may seem that it would be sufficient to simply prepare a high voltage source capable of generating and discharging a high voltage, for example, on the order of kV. However, there is a problem in that supplying a high current to the lamp, which is the object to be energized, causes the brightness irradiated on the object to be heated to become too high, resulting in destruction or evaporation of the thin film of the object to be heated due to excessive heating.

Next, a case will be described in which a current-carrying object and another member are separated from a composite member formed by contacting and integrating a current-carrying object as a conductive material with another member by supplying a pulse current to the current-carrying object. For example, in order to separate and dismantle a first member, which is a thin-film conductor, from a second member made of a material with a lower conductivity than the first member, it is necessary to pass a current as high as possible near the interface between the first member and the second member to instantaneously heat the region and reduce the adhesive force between the first member and the second member. By passing a current of a short duration (short pulse current) through the first member, it is possible to raise the temperature of the shallow surface layer of the joint with the second member before the conductor melts, and melt the adhesive in the region of the second member, particularly the region close to the first member. In addition, as a secondary effect, by increasing the frequency of the current, the skin effect, in which the current flows selectively on the surface of the conductor, can also be utilized. By using a high-frequency current, it is possible to pass a high current intensively near the surface of the first member, in other words, near the interface between the first member and the second member, and instantaneously heat the region. From this perspective, it is preferable to supply a pulsed current to the current-carrying object.

Examples of the material of the first member include conductive materials such as copper, aluminum, iron, nickel, or alloys of these. Examples of the material of the second member include organic materials such as resins and paints, metal oxides, or insulating materials or semiconductors that are mixtures of these.

In other words, in order to reduce the adhesive strength between the first and second members, it is necessary to pass a high current at high frequency near the interface between the first and second members. Considering this point alone, it would seem that it would be sufficient to simply prepare a high-voltage source capable of generating a high voltage, for example, on the order of kilovolts.

However, if the voltage applied to the electrified object is too high, the thin-film conductive portion of the electrified object may be overheated and destroyed or evaporated. This is thought to be because too much energy was supplied to the electrified object, and in this case it cannot be said that the first and second members have been separated.

The above describes the problems that can arise when an electric pulse generator is used in both the lighting circuit of a flash lamp and when it is used to heat a layered composite material. The input energy is defined as the value obtained by integrating the power over time. With the electric pulse generator of the present invention, the time during which energy is supplied to the object to be heated can be set to a short and appropriate value, making it possible to supply energy to a limited range of the object to be heated and to suppress damage to both the part to be heated and the object to be energized.

The switching elements constituting the load circuit section may be semiconductor elements.

As described above, when a switching element is turned on to pass a current resulting from the high voltage charged in the capacitor to an object to be energized, a high current flows instantaneously through the switching element. If the switching element is a mechanical element, the contacts of the switching element will wear out, causing the internal resistance of the switching element to change over time, and in some cases, opening and closing control may become impossible. For this reason, when different objects to be energized are continuously dismantled, the accuracy of the dismantling may decrease over time.

In response to this, by configuring the switching element as a semiconductor element as described above, deterioration and wear over time are suppressed.

Typically, semiconductor elements that can be used include thyristors and high-voltage IGBTs that have high voltage resistance.

a load current flowing through the current-carrying object when the high voltage source and the load circuit unit are electrically connected includes a peak current and a ringing current that flows after the peak current and is less than 10% of a current value of the peak current,
The load current may be configured to substantially taper off without changing polarity between the time when the peak current occurs and the time when the ringing current occurs.

Preferably, the load current has a main pulse width, which is the time width from the occurrence of the peak current to the occurrence of the ringing current, of 1.2 ms or less. With this configuration, the time during which current is supplied to the current-carrying object is extremely short.

the load circuit section includes an inductor,
The first closed circuit may be a series circuit including the capacitor, the current-carrying object, the switching element, and the inductor.

The load circuit section may form a second closed circuit after the capacitor is discharged, the second closed circuit including the diode, the inductor, and the current-carrying object connected in series, but not including the capacitor.

The load circuit section may form a second closed circuit after the capacitor is discharged, including the diode and the inductor connected in series, and not including the capacitor or the current-carrying object.

The dismantling device of the present invention makes it possible to expand the range of voltage applied to the high-voltage source required to maintain a high recovery rate of resources contained in the target object.

1 is a circuit block diagram illustrating a schematic diagram of an electric pulse generator according to a first embodiment. 1 is a diagram showing an example of a flash lamp as an object to be energized; 1 is an example of a cross-sectional view of a composite structure in which an object to be electrically conducted and an object to be heated are integrated. 1 is an example of a cross-sectional view of a composite structure in which an object to be electrically conducted and an object to be heated are integrated. 1 is a diagram illustrating an example of a method for installing an electric current passing object. FIG. 1 is a circuit block diagram showing a schematic diagram of an electric pulse generating device according to a reference example. FIG. 2 is a circuit block diagram showing the operating principle of an electric pulse generating device according to a reference example. FIG. 2 is a circuit block diagram showing the operating principle of an electric pulse generating device according to a reference example. FIG. 2 is a circuit block diagram showing the operating principle of an electric pulse generating device according to a reference example. 11 is a graph showing an example of the behavior of a current flowing through an object after a switching element is turned on in the electric pulse generator of the reference example. 1 is a diagram illustrating a mode in which excessive heat is supplied to an object to be heated when a current flows through the object for a long period of time. 11 is another diagram showing a schematic diagram of a state in which excessive heat is supplied to an object to be heated when a current flowing through the object to be energized becomes long. 1 is a circuit diagram illustrating the operation principle of an electric pulse generator according to a first embodiment. 1 is a circuit diagram illustrating the operation principle of an electric pulse generator according to a first embodiment. 9 is a graph showing an example of the behavior of a current flowing through an object to be energized after a switching element is turned on in the electric pulse generator of the first embodiment, in which the graph of FIG. 8 is also shown. FIG. 10C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the first embodiment, shown in accordance with FIG. 10B. FIG. 10C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the first embodiment, shown in accordance with FIG. 10B. FIG. 10C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the first embodiment, shown in accordance with FIG. 10B. FIG. 11 is a circuit block diagram showing a schematic diagram of an electric pulse generator according to a second embodiment. FIG. 11 is a circuit diagram showing the operation principle of an electric pulse generator according to a second embodiment. FIG. 11 is a circuit diagram showing the operation principle of an electric pulse generator according to a second embodiment. 12 is a graph showing an example of the behavior of a current flowing through an object to be energized after a switching element is turned on in an electric pulse generator of the second embodiment, in which the graph of FIG. 11 is also shown. FIG. 16C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the second embodiment, shown in accordance with FIG. 16B. FIG. 16C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the second embodiment, shown in accordance with FIG. 16B. FIG. 11 is a circuit block diagram illustrating an electric pulse generator according to a third embodiment. FIG. 11 is a circuit diagram showing the operation principle of an electric pulse generator according to a third embodiment. FIG. 11 is a circuit diagram showing the operation principle of an electric pulse generator according to a third embodiment. FIG. 21C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the third embodiment, shown following the example of FIG. 21B. FIG. 21C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the third embodiment, shown following the example of FIG. 21B. FIG. 21C is a circuit diagram showing another example of the configuration of the load circuit section included in the electric pulse generator of the third embodiment, shown following the example of FIG. 21B. FIG. 1 is a circuit block diagram showing a schematic diagram of a conventional electric pulse generator.

Each embodiment of the electrical pulse generator of the present invention will be described with reference to the drawings as appropriate. Note that the following drawings are schematic illustrations. Also, the circuits illustrated in each drawing are examples, and the scope of the present invention includes circuits equivalent to the illustrated circuits.

[First embodiment]
Fig. 1 is a circuit block diagram showing a schematic configuration of an electric pulse generator according to the present embodiment. As shown in Fig. 1, the electric pulse generator 1 includes a high voltage source 5 and a load circuit section 2. The high voltage source 5 is a voltage source capable of outputting a voltage on the order of kV.

The electric pulse generator 1 of this embodiment includes a switching element 6 that switches between electrical connection and disconnection between the high voltage source 5 and the load circuit section 2. Note that while FIG. 1 illustrates the switching element 6 as being provided outside the high voltage source 5, it may also be provided inside the high voltage source 5.

The load circuit section 2 of the electric pulse generator 1 of this embodiment includes a capacitor 11, a switching element 13, a diode 15, an inductor 17, and an object to be energized 3. When the electric pulse generator 1 is used to heat an object (object to be heated), the object to be heated may be integrated with the object to be energized 3, or the object to be energized 3 and the object to be heated may be located apart from each other. This point will be described later.

The capacitor 11 is arranged so that it can be charged based on the output voltage from the high voltage source 5 when the switching element 6 is turned on and the high voltage source 5 and the load circuit section 2 are electrically connected. The capacitor 11 is structured so that it can be charged with a voltage on the order of kV.

The switching element 13 is connected in series with the current-carrying object 3. When the switching element 13 is turned on, a series circuit (first closed circuit U1) is formed that includes the capacitor 11, the current-carrying object 3, the switching element 13, and the inductor 17. The switching element 13 is composed of a semiconductor element, typically a thyristor or an IGBT.

When the switching element 13 is a thyristor, the switching element 13 is controlled to be turned on/off based on a gate signal. In detail, once a signal voltage is applied between the gate terminal and the cathode terminal as a gate signal, the thyristor becomes conductive thereafter.

The diode 15 has a cathode terminal connected to the first closed circuit U1 at a connection point P1, and an anode terminal connected to the first closed circuit U1 at a connection point P2. Here, the relationship between the connection points P1 and P2 is as follows. When the switching element 13 transitions from a non-conductive state to a conductive state while the capacitor 11 is in a charged state, the connection point P1 is electrically closer to the high potential side terminal of the capacitor 11 than the connection point P2.

Figure 2 is a schematic diagram of an embodiment in which the object 3 to be energized is a flash lamp. As shown in Figure 2, the flash lamp 7 includes an arc tube 23 made of quartz glass or the like, and a pair of electrodes (21, 22). Gas such as xenon is sealed inside the arc tube 23. The electric pulse generator 1 supplies an electric pulse to the flash lamp 7 as the object 3 to be energized, more specifically between the pair of electrodes (21, 22), causing the flash lamp 7 to emit light for a short period of time. A high energy of, for example, 5 kJ is supplied to the flash lamp 7.

Light L7 from the flash lamp 7 is irradiated onto the object to be heated 30. This light L7 is absorbed by the surface region 31 of the object to be heated 30, thereby heating the surface region 31. For example, in a manufacturing process for a solar cell made of laminated organic materials, the light L7 from the flash lamp 7 can be used to heat the surface of the organic layer as the object to be heated 30. Specifically, a thin film of about 1 μm or less on the surface of the object to be heated 30 can be instantaneously heated to an extremely high temperature of about 800° C. By appropriately controlling the pulse width and current value of the electric pulse supplied from the electric pulse generator 1 to the flash lamp 7, it is possible to selectively heat only the surface region 31 of the object to be heated 30.

3 is an example of a cross-sectional view showing a composite structure of metal and insulating material as an example in which the current-carrying object 3 and the heating object 30 are integrated. The composite structure 4 shown in FIG. 3 includes a metal plate 41 as the current-carrying object 3, and constituent materials 43 and 45 as the heating object 30. When an electric pulse is supplied to the metal plate 41 as the current-carrying object 3 by the electric pulse generator 1, the current-carrying object 3 is heated by an electric energy defined by (current) ² ×(resistance value R of the metal plate 41), and this heat is transferred to the heating object 30. As a result, the heating object 30 and the current-carrying object 3 are peeled off. In this embodiment, a part of the load circuit unit 2 is formed by the composite structure 4 in which the current-carrying object 3 and the heating object 30 are integrated.

In the embodiment shown in FIG. 3, the method of transmitting energy to the heated object 30 is different, but the concept of transferring energy to a limited area is essentially the same as in the embodiment shown in FIG. 2.

In other words, as described above with reference to FIG. 2, when the object 3 to be energized is a flash lamp 7, a short pulse of energy is supplied to the flash lamp 7, and light from the flash lamp 7 is supplied to the object to be heated 30. Also, as described above with reference to FIG. 3, when the object 3 to be energized is a composite structure 4, a short pulse of energy is supplied to a metal plate 41 included in the composite structure 4, and heat from the metal plate 41 is supplied to the object to be heated 30. Thus, although the embodiment of FIG. 2 and the embodiment of FIG. 3 differ in that the means of energy transmission is light or heat, the two are essentially the same in terms of the technology for heating the surface of the object to be heated 30.

Figure 4 is an example of a cross-sectional view that shows a composite structure of metal and insulating material as an example in which the current-carrying object 3 and the heating object 30 are integrated. For example, when the composite structure 4 is a solar cell, as shown in Figure 4, the composite structure 4 includes an upper metal electrode 47, an organic thin film layer 48, and a transparent electrode 49.

For example, in the manufacturing process of a solar cell, moderate heating of the shallow interface region of the organic thin film layer 48 melts the organic thin film layer 48 and improves adhesion between the upper metal electrode 47 and the organic thin film layer 48. Increasing adhesion between the two leads to lower contact resistance at the interface and improved mechanical strength. However, if heating extends to a deep region of the organic thin film layer 48, the deep region will melt, which is expected to have an adverse effect on the function of the solar cell itself.

For example, when a short pulse of high energy is supplied to the upper metal electrode 47 of a used solar cell, the organic thin film layer 48 and the upper metal electrode 47 are peeled off. This allows the metal contained in the upper metal electrode 47 to be recovered and recycled.

In the embodiment shown in FIG. 4, a part of the load circuit section 2 is formed by a composite structure 4 in which the object to be energized 3 and the object to be heated 30 are integrated.

As shown in FIG. 5, the composite structure 4 may be placed on the circuit while immersed in the conductive solution 55. In the example shown in FIG. 5, the composite structure 4 cut to an appropriate size is immersed in the solution 55 while being contained in a container 56 having an opening on the periphery. An electric pulse is then supplied into the solution 55 via a pair of electrodes (51, 52). By applying a very high voltage from the pair of electrodes (51, 52), electricity flows through the metal plate 41 of the composite structure 4 via the conductive solution 55. This heats the interface between the metal plate 41 and the heating object 30 (constituent material 43 and constituent material 45) shown in FIG. 3. In the example shown in FIG. 5, the combined resistance component of the metal plate 41 and the conductive solution 55 corresponds to the current-carrying object 3. The solution 55 is also included in the heating object 30 as a result. In other words, the conductive solution 55 serves both as the current-carrying object 3 and the heating object 30, and constitutes a part of the load circuit section 2.

Before explaining the operating principle of the electrical pulse generator 1 shown in FIG. 1, we will explain the operating principle of the reference example electrical pulse generator 71 shown in FIG. 6.

Figure 6 is a circuit block diagram showing a schematic configuration of an electric pulse generator 71 as a reference example, following the example of Figure 1. The load circuit section 72 of the electric pulse generator 71 shown in Figure 6 differs from the electric pulse generator 1 shown in Figure 1 in that it does not include a diode 15 and an inductor 17. That is, in the load circuit section 72 shown in Figure 6, when the switching element 13 is turned on, a series circuit (closed circuit U70) including the capacitor 11 and the object 3 to be energized is formed.

When starting the electric pulse generator 71, the switching element 6 is first turned on to charge the capacitor 11 based on the output voltage from the high voltage source 5 (see FIG. 7A). At this time, the switching element 13 is turned off so that there is no electrical continuity between the high voltage source 5 and the object 3 to be energized.

When charging of the capacitor 11 is completed, the switching element 6 is made non-conductive to disconnect the electrical connection between the high voltage source 5 and the load circuit section 72. Then, the switching element 13 is made conductive to pass a current derived from the charging voltage of the capacitor 11 to the current-carrying object 3 (see FIG. 7B).

As described above, the high voltage source 5 is a voltage source capable of outputting a voltage on the order of kV, and the capacitor 11 is also configured to be capable of charging a voltage on the order of kV. Therefore, when the switching element 13 is in a conductive state, a high load current iZ resulting from a voltage on the order of kV instantaneously flows through the current-carrying object 3 via the switching element 13.

As described above with reference to FIG. 2, when the object 3 to be energized is a flash lamp 7, a current flows between a pair of electrodes (21, 22) while the gas enclosed in the light emitting tube 23 becomes plasma. The plasma-excited gas simultaneously emits light L7 of a specific wavelength. At this time, from the viewpoint of increasing the efficiency of plasma generation, it is important to pass a high current in an extremely short time, that is, to increase the amount of current increase per unit time. As described above with reference to FIG. 2, the light L7 emitted from the flash lamp 7 reaches the object 30 to be heated, and its surface region 31 is heated.

Also, as described above with reference to FIG. 3, for example, when the object 3 to be electrified is a composite structure 4 made up of multiple stacked layers, a high current flows instantaneously through the object 3 to be electrified, causing it to heat up, and this heat is transferred to the object to be heated 30. The high frequency of this current iZ also works to its advantage, and due to the skin effect, it may flow locally near the surface layer of the conductor contained in the object 3 to be electrified (metal plate 41 in the example of FIG. 3). In a short period of time, the temperature of the interface between the multiple layers that make up the composite structure 4 rises rapidly, causing the interface between the two to be locally heated and destroyed, and the two to be separated.

Incidentally, the discharge current flowing from the capacitor 11 shown in Fig. 7B flows into the capacitor 11, and the capacitor 11 starts to charge with the reverse polarity. After that, when the charging of the capacitor 11 is completed, a reverse current iZ flows through the current-carrying object 3 due to the charging voltage of the capacitor 11 (see Fig. 7C). In this way, an oscillating current continues to flow through the current-carrying object 3 while reversing its polarity. The period of this oscillating current is determined by the capacitance component of the capacitor 11 and the parasitic inductance component present on the circuit in the closed circuit U70, as shown in the following formula. The period of oscillation is fixed.
1/period = frequency f = 1/(2π√(L/C))
C: Capacitance component L: Inductance component The absolute value of the current iZ attenuates over time due to Joule heat and the like caused by the internal resistance of the closed circuit U70.

Fig. 8 is an example of a graph showing the behavior of the current iZ flowing through the current-carrying object 3 and the voltage across the current-carrying object 3 after the switching element 13 is turned on after the capacitor 11 is completely charged by the output voltage from the high-voltage source 5 using the electric pulse generator 71 as the reference example shown in Fig. 6. According to Fig. 8, a current flows through the current-carrying object 3 for a period of about several ms. The circuit conditions in Fig. 8 are as follows, and this is a reference example in which the current-carrying object 3 is a flash lamp.
Inductance component (same as inductor 17 in FIG. 1): 12 μH
Resistance value of current-carrying object 3: 50 mΩ
Capacitance of capacitor 11: 400 μF
Charging voltage of capacitor 11: 4000 V

In the graph of FIG. 8, the time that current flows through the object 3 is at most a few milliseconds, which is much shorter than one second. For this reason, it seems that the electric pulse generator 71 of the reference example also flows an instantaneous current through the object 3. However, the inventors conceived that if the pulse width of the current could be narrowed even further than that of the electric pulse generator 71, the following would be possible.

(1) When the object 3 to be energized is a flash lamp 7, the light emission efficiency of the flash lamp 7 is increased by shortening the pulse width, while improving the control of heating of the surface region 31 of the object 30 to be heated.

Conversely, if the time that the current iZ flows through the flash lamp 7 is increased, the efficiency of plasma generation decreases and the time that light is irradiated onto the object to be heated 30 also increases. As a result, as shown by the hatched area in Figure 9A, heat reaches not only the surface region 31 of the object to be heated 30 but also the lower layer 32 located deeper than the surface region 31, causing heating. This may result in damage to the lower layer 32 (see Figure 9A).

(2) When the object 3 to be energized is a composite structure 4, the controllability of the heating of the object 30 to be heated can be improved by using a short pulse width, thereby increasing the separation efficiency.

Conversely, if the current iZ flows through the composite structure 4 for a long time, parts of the metal plate 41 may become excessively heated, break off, and evaporate (metal plate parts 41a, 41b), adhering to or mixing with the detached component material 43a, making it unsuitable for reuse (see Figure 9B).

As described above, in this embodiment, the switching element 13 is a semiconductor element. As described above, considering that the discharge current from the capacitor 11 charged by a voltage of the order of kV through the high voltage source 5 flows instantaneously through the switching element 13, if the switching element 13 is a mechanical switch, the contacts may wear out and the resistance of the contacts may increase with the use of the electric pulse generator 1 over time. Ideally, the value of the current peak is determined by the resistance value of the current-carrying object 3 (current peak value = supplied high voltage / resistance value of the current-carrying object 3). However, if the resistance value increases due to wear of the contacts, the sum of the resistance value of the current-carrying object 3 and the resistance value of the current-carrying object 3 is calculated as the overall resistance value, and the peak value of the pulse current decreases. This is not preferable from the viewpoint of reproducibility of the energy amount of the electric pulse, which is one of the problems described in the present invention. In consideration of long-term use of the electric pulse generator 1, it is preferable that the switching element 13 is a semiconductor element.

Furthermore, in the electrical pulse generator 1 shown in FIG. 1, the load circuit section 2 is equipped with an inductor 17. However, it is also possible to use the parasitic inductance present in the closed circuit without providing the inductor 17.

As mentioned above, the maximum allowable value for the current rise speed (ΔI/Δt) may be specified as a rated value for semiconductor switches that can be used as switching elements 13. If a current that is too steep flows through a semiconductor switch, the current may not be able to diffuse in time inside the semiconductor junction, causing the current to concentrate locally and causing the semiconductor switch to heat up and be destroyed. From this perspective, the above-mentioned maximum allowable value for the current rise speed may be set.

In order to reduce the rate at which this current rises, it is effective to intentionally insert an inductor 17, as shown in Figure 1. By employing a semiconductor switch, it is possible to output an electrical pulse that has high reproducibility and little change over time, but by inserting an inductor 17, a trade-off occurs in which the slope of the increase in the current pulse is reduced. In order to achieve the objective of the present invention of providing a reproducible electrical pulse while also shortening the period over which energy is provided, it is preferable to make further improvements to the electrical pulse generating circuit. This will be explained below. Note that in the following drawings, only the load circuit section 2 in Figure 1 is shown as appropriate.

As with the electric pulse generator 71 as a reference example, when charging of the capacitor 11 is completed, the switching element 13 is turned on to allow the current iZ derived from the charging voltage of the capacitor 11 to flow to the current-carrying object 3 (see FIG. 10A). When the switching element 13 is turned on, the current iZ derived from a voltage on the order of kV instantaneously flows through the current-carrying object 3 via the switching element 13.

As described above, the load circuit section 2 of the electric pulse generator 1 includes the diode 15. When the switching element 13 transitions from a non-conductive state to a conductive state while the capacitor 11 is in a charged state, the connection point P1 of the cathode terminal of the diode 15 is electrically closer to the high potential terminal of the capacitor 11 than the connection point P2 of the anode terminal. Therefore, the current iZ that flows through the current-carrying object 3 bypasses the capacitor 11 and flows through the diode 15 (see FIG. 10B). In other words, after the capacitor 11 is discharged, the diode 15, the inductor 17, and the current-carrying object 3 are connected in series to form a second closed circuit U2 that does not include the capacitor 11.

In other words, unlike the electric pulse generator 71 of the reference example, the electric pulse generator 1 of this embodiment does not cause the capacitor 11 to be charged again with the opposite polarity, so the time during which the current iZ flows through the object 3 to be energized is significantly shortened.

Figure 11 is an example of a graph showing the behavior of the current iZ flowing through the current-carrying object 3 and the voltage across the current-carrying object 3 after the switching element 13 is turned on after the capacitor 11 is completely charged by the output voltage from the high voltage source 5 using the electric pulse generator 1 of this embodiment. For comparison, FIG. 11 also shows a graph showing the behavior of the current iZ in the electric pulse generator 71 of the reference example shown in FIG. 8. Comparing the waveforms of the two, it can be seen that the time (τ1) during which the current iZ flows through the current-carrying object 3 is shortened according to the electric pulse generator 1 of this embodiment compared to the time (τ0) during which the current iZ flows when the diode 15 is not present (reference example).

The circuit conditions in Fig. 11 are as follows. That is, the circuit conditions in Fig. 11 are the same as the circuit conditions in Fig. 8 except for the presence of diode 15. The following numerical values are a reference example in which a flash lamp is the current-carrying object 3.
Inductance component (same as inductor 17 in FIG. 1): 12 μH
Resistance value of current-carrying object 3: 50 mΩ
Capacitance of capacitor 11: 400 μF
Charging voltage of capacitor 11: 4000 V
Diode 15: Yes

More specifically, the current iZ flowing through the current-carrying object 3 may include a ringing current that is less than 10% of the current value of the peak current that flows after the peak current. This ringing current is related to a certain parasitic inductance in the circuit. However, between the occurrence of the peak current and the transition of the current to near zero, the current essentially tapers off without changing polarity. It has been confirmed that the period (τ1) of the main pulse width, which is the time width until the current waveform begins to essentially taper off, is a short time of about 1.2 ms. In the period (τ3) following the period (τ1), a ringing current that is less than 10% of the current value of the peak current may still be observed, but this level is considered to have no significant effect on heating.

Figures 12 to 14 are circuit diagrams that show, in accordance with Figure 10B, another example of the configuration of the load circuit section 2 included in the electrical pulse generator 1 of this embodiment. That is, Figures 12 to 14 all show the behavior of the current iZ after the discharge of the capacitor 11 is complete.

In either circuit method, when the capacitor 11 is charged, a series circuit (first closed circuit U1) is formed that includes the capacitor 11, the current-carrying object 3, the switching element 13, and the inductor 17. Then, when the switching element 13 transitions from a non-conducting state to a conducting state while the capacitor 11 is in a charged state, the current iZ that flowed through the current-carrying object 3 bypasses the capacitor 11 and flows through the diode 15. After the capacitor 11 is discharged, the diode 15, the inductor 17, and the current-carrying object 3 are connected in series to form a second closed circuit U2 that does not include the capacitor 11.

As described above, the electric pulse generator 1 of this embodiment realizes a short pulse, so that the object to be heated 30 can be efficiently heated in an appropriate range with good reproducibility while reducing damage to the object to be energized 3 and the object to be heated 30.

[Second embodiment]
The second embodiment of the electric pulse generator according to the present invention will be described mainly with respect to the differences from the first embodiment. Note that the same reference numerals are used to denote elements common to the first embodiment, and the description thereof will be simplified or omitted.

Figure 15 is a circuit block diagram showing the configuration of the electric pulse generator 1 of this embodiment, following the same pattern as Figure 1. The electric pulse generator 1 of this embodiment differs from the first embodiment in the configuration of the load circuit section 2. Specifically, it differs in that the diode 15 is connected in parallel to the series circuit of the current-carrying object 3 and the capacitor 11.

The operation of the electrical pulse generator 1 of this embodiment will be described with reference to Figures 16A and 16B. Figures 16A and 16B are similar to Figures 10A and 10B, in which only the load circuit section 2 of the electrical pulse generator 1 of this embodiment is extracted.

When charging of the capacitor 11 is completed, the switching element 13 is turned on to pass the current iZ derived from the charging voltage of the capacitor 11 to the current-carrying object 3 (see FIG. 16A). When the switching element 13 is turned on, the current iZ derived from a voltage on the order of kV instantaneously flows through the current-carrying object 3 via the switching element 13.

The load circuit section 2 of the electric pulse generator 1 of this embodiment also includes a diode 15, as in the first embodiment. When the switching element 13 transitions from a non-conductive state to a conductive state while the capacitor 11 is in a charged state, the connection point P1 of the cathode terminal of the diode 15 is electrically closer to the high potential terminal of the capacitor 11 than the connection point P2 of the anode terminal. Therefore, the current iZ that flows through the current-carrying object 3 bypasses the capacitor 11 and the current-carrying object 3 and flows through the diode 15 (see FIG. 16B). In other words, after the capacitor 11 is discharged, the diode 15 and the inductor 17 are connected in series, and a second closed circuit U2 is formed that does not include the capacitor 11 and the current-carrying object 3.

In other words, in the electric pulse generator 1 of this embodiment, the capacitor 11 does not charge with reverse polarity, so the time during which the current iZ flows through the object 3 is significantly shortened. Furthermore, compared to the first embodiment, the time during which the current iZ flows through the object 3 can be further shortened.

As described above with reference to Figs. 16A to 16B, in the configuration of the electric pulse generator 1 of this embodiment, the capacitor 11 is charged via the current-carrying object 3. Here, as described above with reference to Fig. 2, if the current-carrying object 3 is a flash lamp 7, the flash lamp 7 exhibits insulating properties until it starts to light up, and during this period the current-carrying object 3 is essentially insulating. In this case, the capacitor 11 cannot be charged via the current-carrying object 3. From this perspective, in order to ensure a charging path to the capacitor 11, a resistor of about several ohms may be connected in parallel to the current-carrying object 3 (here, the flash lamp 7). Also, a diode may be added to ensure the charging path.

Figure 17 is an example of a graph showing the behavior of the current iZ flowing through the current-carrying object 3 after the switching element 13 is turned on after the capacitor 11 is completely charged by the output voltage from the high voltage source 5 using the electric pulse generator 1 of this embodiment. For comparison, Figure 17 also shows a graph showing the behavior of the current iZ in the electric pulse generator 71 of the first embodiment shown in Figure 11.

According to FIG. 17, it is confirmed that the time during which the current iZ flows through the object 3 is further shortened by using the electric pulse generator 1 of this embodiment than in the first embodiment. According to FIG. 17, in the case of the electric pulse generator 1 of the first embodiment, the period (τ1) of the main pulse width, which is the time width from the generation timing of the peak current to the timing when the current starts to taper off, is about 1.2 ms, whereas in the case of this embodiment, the period (τ2) is about 0.2 ms. In other words, referring to FIG. 11 in addition to FIG. 17, it can be seen that the period of the pulse width can be significantly shortened according to the electric pulse generator 1 of this embodiment compared to the electric pulse generator 71 of the reference example.

The electric pulse generator 1 of this embodiment is characterized in that the diode 15 is arranged in parallel to the connection circuit between the capacitor 11 and the current-carrying object 3, as shown in FIG. 15. By arranging the capacitor 11, the current-carrying object 3, and the diode 15 as close as possible to each other, the occurrence of a current derived from a parasitic inductance other than the inductor 17 on the circuit in the second closed circuit U2 is suppressed. As a result, with the electric pulse generator 1 of this embodiment, as shown in FIG. 17, almost no ringing current flows after the main pulse is generated.

Figures 18 to 19 are circuit diagrams that show, in a schematic manner similar to Figure 16B, another example of the configuration of the load circuit section 2 included in the electrical pulse generator 1 of this embodiment. That is, Figures 18 to 19 all show the behavior of the current iZ after the discharge of the capacitor 11 is completed.

In either circuit, when the capacitor 11 is charged, a series circuit (first closed circuit U1) is formed that includes the capacitor 11, the current-carrying object 3, the switching element 13, and the inductor 17. Then, when the switching element 13 transitions from a non-conducting state to a conducting state while the capacitor 11 is in a charged state, the current iZ that flowed through the current-carrying object 3 bypasses the capacitor 11 and the current-carrying object 3 and flows through the diode 15. After the capacitor 11 is discharged, the diode 15 and the inductor 17 are connected in series to form a second closed circuit U2 that does not include the capacitor 11 or the current-carrying object 3.

As described above, the electric pulse generator 1 of this embodiment produces an electric pulse with a shorter pulse width than the first embodiment, so that the object to be heated 30 can be efficiently heated in an appropriate range with good reproducibility while reducing damage to the object to be energized 3 and the object to be heated 30.

[Third embodiment]
The third embodiment of the electric pulse generator according to the present invention will be described mainly with respect to the differences from the first embodiment. Note that the same reference numerals are used to denote elements common to the first embodiment, and the description thereof will be simplified or omitted.

Figure 20 is a circuit block diagram showing the configuration of the electrical pulse generator 1 of this embodiment, following the same pattern as Figure 1. The electrical pulse generator 1 of this embodiment differs from the first embodiment in the configuration of the load circuit section 2. Specifically, it differs in that the diode 15 is connected in parallel to the inductor 17.

The operation of the electrical pulse generator 1 of this embodiment will be described with reference to Figures 21A and 21B. In Figures 21A and 21B, only the load circuit section 2 of the electrical pulse generator 1 of this embodiment is extracted, following the example of Figures 10A and 10B.

When charging of the capacitor 11 is completed, the switching element 13 is turned on to pass the current iZ derived from the charging voltage of the capacitor 11 to the current-carrying object 3 (see FIG. 21A). When the switching element 13 is turned on, the current iZ derived from a voltage on the order of kV instantaneously flows through the current-carrying object 3 via the switching element 13.

The load circuit section 2 of the electric pulse generator 1 of this embodiment also includes a diode 15, as in the first embodiment. When the switching element 13 transitions from a non-conductive state to a conductive state while the capacitor 11 is in a charged state, the connection point P1 of the cathode terminal of the diode 15 is electrically closer to the high potential terminal of the capacitor 11 than the connection point P2 of the anode terminal. For this reason, at the time of FIG. 21A, the current iZ from the capacitor 11 flows to the current-carrying object 3 via the inductor 17, not via the diode 15. After that, when an induced current is generated from the inductor 17, the current iZ flows from the connection point P2 to the connection point P1 via the diode 15 (see FIG. 21B). After the current iZ flows instantaneously toward the current-carrying object 3, the current no longer flows toward the current-carrying object 3, but flows through the second closed circuit U2 formed by the inductor 17 and the diode 15.

In other words, in this embodiment, as in the second embodiment, after the capacitor 11 discharges, the diode 15 and the inductor 17 are connected in series to form a second closed circuit U2 that does not include the capacitor 11 or the current-carrying object 3.

As a result, the time during which the current iZ flows through the object 3 can be further shortened in the electric pulse generator 1 of this embodiment than in the first embodiment.

However, in the electric pulse generator 1 of this embodiment, a current originating from the parasitic inductance in the first closed circuit U1 flows through the current-carrying object 3, and as a result, the ringing current may continue to flow while attenuating by about 10% or less. In this case, the current flowing through the current-carrying object 3 does not actually become zero. This is also true of the electric pulse generator 1 of the first embodiment described above with reference to FIG. 1, etc. In contrast, in the electric pulse generator 1 of the second embodiment described above with reference to FIG. 15, etc., the current path flowing through the current-carrying object 3 is bypassed by the diode 15, so that the current flowing through the current-carrying object 3 can be made almost zero.

Figures 22 to 24 are circuit diagrams that show, in accordance with Figure 21B, another example of the configuration of the load circuit section 2 included in the electrical pulse generator 1 of this embodiment. That is, Figures 22 to 24 all show the behavior of the current iZ after the discharge of the capacitor 11 is complete.

In either circuit, when the capacitor 11 is charged, a series circuit (first closed circuit U1) is formed that includes the capacitor 11, the current-carrying object 3, the switching element 13, and the inductor 17. Then, when the switching element 13 transitions from a non-conducting state to a conducting state while the capacitor 11 is in a charged state, the current iZ flows instantaneously through the current-carrying object 3, and then the induced current of the inductor 17 flows through the second closed circuit U2, which is formed by connecting the diode 15 and the inductor 17 in series and does not include the capacitor 11 or the current-carrying object 3.

As described above, the electric pulse generator 1 of this embodiment realizes a short pulse, so that the object to be heated 30 can be efficiently heated in an appropriate range with good reproducibility while reducing damage to the object to be energized 3 and the object to be heated 30.

From the above explanation, it can be understood that the electrical pulse generator 1 of each embodiment can reduce the variation and fluctuation of the output energy while shortening the period during which the electrical pulse is provided.

Actual experiments confirmed that, as described above with reference to FIG. 2, when the object 3 to be energized is a flash lamp 7, it is possible to improve the light emission efficiency of the flash lamp 7 by turning on the flash lamp 7 using the electric pulse generator 1, while controlling the heating depth of the object 30 to be heated. Also, as described above with reference to FIG. 3, the principle is the same when an electric pulse is supplied to a composite structure 4 in which the object 3 to be energized and the object 30 to be heated are integrated using the electric pulse generator 1, and by controlling the heating depth of the object 30 to be heated, it is expected that the layers can be separated with higher accuracy.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail to provide a better understanding of the present invention, and is not necessarily limited to having all of the configurations described. The scope of the present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope of the claims.

1: Electric pulse generator 2: Load circuit section 3: Electrically conductive object 4: Composite structure 5: High voltage source 6: Switching element 7: Flash lamp 11: Capacitor 13: Switching element 15: Diode 17: Inductor 23: Arc tube 30: Heating object 31: Surface area of heating object 32: Lower layer 33: Screw member 41: Metal plate 41a, 41b: Part derived from metal plate 43: Constituent material 45: Constituent material 47: Upper metal electrode 48: Organic thin film layer 49: Transparent electrode layer 51: Electrode 52: Electrode 55: Conductive solution 56: Storage container 71: Reference example electric pulse generator 72: Load circuit section 90: Electrically conductive object 91: Capacitor 92: Mechanical switch 95: High voltage source 96: Switching element 100: Conventional example electric pulse generator L7: Light P1 : Connection point P2 : Connection point U1 : First closed circuit U2 : Second closed circuit iZ : Current τ0 to τ3: Period

Claims (8)

An electric pulse generating device that applies an electric pulse to an electric current application target,
a high voltage source and a load circuit section arranged to be able to apply an output voltage from the high voltage source;
The load circuit section includes:
The current passing object;
A switching element connected in series to the current-carrying object;
a capacitor disposed in a position capable of being charged based on an output voltage from the high voltage source when the high voltage source and the load circuit unit are electrically connected;
a diode including an anode terminal and a cathode terminal;
the load circuit unit forms a first closed circuit, which is a series circuit including the capacitor, the current-carrying object, and the switching element, when the switching element is in a conductive state;
the anode terminal and the cathode terminal of the diode are each connected to two points on the first closed circuit,
13. An electric pulse generator comprising: a first closed circuit connected to said cathode terminal and said first closed circuit, and a second closed circuit connected to said anode terminal and said first closed circuit, said first closed circuit being electrically closer to a high potential side terminal of said capacitor than to a connection point between said anode terminal and said first closed circuit, at a point when said switching element is transitioned from a non-conducting state to a conducting state while said capacitor is in a charged state. a load current flowing through the current-carrying object when the high voltage source and the load circuit unit are electrically connected includes a peak current and a ringing current that flows after the peak current and is less than 10% of a current value of the peak current,
2. The electric pulse generator according to claim 1, wherein the load current substantially tapers off without changing polarity between the occurrence timing of the peak current and the occurrence timing of the ringing current. The electric pulse generator according to claim 2, characterized in that the load current has a main pulse width, which is the time width from the occurrence timing of the peak current to the occurrence timing of the ringing current, of 1.2 ms or less. the load circuit section includes an inductor,
4. The electric pulse generator according to claim 1, wherein the first closed circuit is a series circuit including the capacitor, the current-carrying object, the switching element, and the inductor. The electric pulse generator according to claim 4, characterized in that the load circuit section forms a second closed circuit including the diode, the inductor, and the current-carrying object connected in series, and not including the capacitor, after the capacitor is discharged. The electric pulse generator according to claim 4, characterized in that the load circuit section forms a second closed circuit that includes the diode and the inductor connected in series after the capacitor is discharged, and does not include the capacitor or the current-carrying object. The electrical pulse generator according to any one of claims 1 to 3, characterized in that the switching element is made of a semiconductor element. The electric pulse generator according to any one of claims 1 to 3, characterized in that the object to be energized is a flash lamp.

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