JP2007005370A - Circuit element for exciting light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of parts, the number of mounting processes and a part mounting area by integrating a plurality of parts. <P>SOLUTION: A circuit element for exciting a light source has an integrated structure consisting of a ceramic capacitor 11 having a plurality of ceramic chips of an unpredetermined dimension and charging a predetermined voltage to be input from the outside; a sheet-like Ni ferrite core 12a stacked on a single side portion or a double side portion of the ceramic capacitor 11; a primary side winding 12b wound around a winding core formed by stacking the ceramic capacitor 11 and the Ni ferrite core 12a, and applied with a voltage charged to the ceramic capacitor 11; and a secondary side winding 12c wound around the winding core, and generating a high trigger output voltage induced by a current flowing through the primary side winding 12b by the application of the charging voltage and used for exciting the light source. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source excitation circuit element for exciting a light source of a photographic strobe xenon (Xe) tube or other optical electronic equipment.

  In general, a light source such as a xenon tube is used for a photographic strobe. By applying a predetermined trigger voltage to the light source to emit light, it is possible to take a photograph in an optimum light amount environment.

FIG. 8 is a diagram illustrating the circuit configuration of the strobe.
This strobe is connected to a series circuit including a current limiting resistor 1 and an off thyristor 2 on the output side of a power transformer (not shown). This current limiting resistor 1 is connected between one end side of the secondary winding of the power transformer and the anode of the off thyristor 2, and when a predetermined voltage is applied from the power transformer, a predetermined current value regulated. Has the function of flowing. The cathode of the off thyristor 2 is connected to the ground potential line together with the other end of the secondary winding of the power transformer. The off thyristor 2 is normally non-conductive.

  The primary side winding 41 of the transformer winding coil 4 is connected to the common connection portion of the current limiting resistor 1 and the off thyristor 2 via the trigger capacitor 3, and the other end portion of the primary side winding 41 is connected to the ground potential. Connected to the line. When the strobe is in a steady state, the trigger capacitor 3 is charged by a current flowing from the power transformer side through a path of the current limiting resistor 1, the trigger capacitor 3, the primary winding 41 of the transformer winding coil 4, and the ground line. Do.

  The transforming winding coil 4 is a winding for generating a high voltage constituting a strobe. The transformer winding coil 4 includes a ferrite core 42 that is a magnetic material, the primary winding 41 that is wound around the ferrite core 42, and a secondary winding 43 that is also wound around the ferrite core 42. It consists of. One end of the secondary winding 43 of the transformer winding coil 4 is grounded together with the primary winding 41, and the other end of the secondary winding 43 is a high voltage output line.

  Reference numeral 5 denotes, for example, a xenon tube as a light source constituting the strobe light emitting unit. The xenon tube 5 is connected in parallel to a series circuit of the current limiting resistor 1 and the off thyristor 2. A high voltage electrode plate 6 is disposed in the vicinity of the xenon tube 5 and is connected to the other end of the secondary winding 43 of the above-described winding coil 4 for voltage transformation. Reference numeral 7 denotes a main capacitor connected in parallel to the xenon tube 5.

  In the strobe as described above, in a steady state, the current limiting resistor 1, the trigger capacitor 3, the primary winding 41 of the transformer winding coil 4, and the ground line are arranged from one end of the secondary winding of the power transformer. Since the energization circuit is formed, the trigger capacitor 3 charges the voltage supplied from the power transformer under the energization current of the energization circuit.

  In this state, when the gate electrode of the off thyristor 2 is turned on, the anode and the cathode of the off thyristor 2 become conductive, the voltage charged in the trigger capacitor 3 is rapidly discharged, and the primary side of the transformer winding coil 4 A discharge current flows through the winding 41. As a result, a high voltage is induced in the secondary winding 43 of the transformer winding coil 4 and is applied between the high voltage electrode plate 6 and the cathode of the xenon tube 5. As a result, the xenon tube 5 is ignited. Due to this ignition, a discharge current rapidly flows into the xenon tube 5 from the main capacitor 7 and exhibits a light emission state.

  By the way, in recent years, digital cameras and mobile phones are becoming more and more light and thin, and accordingly, miniaturization of strobes used in these optical electronic devices has become an urgent task.

However, in the conventional strobe, since the trigger capacitor 3 and the winding coil 4 for transformation are each a single component, it is generally incorporated individually in a strobe component mounting board (Patent Document 1).
JP 2003-131294 A

  Therefore, in the strobe as described above, since the trigger capacitor 3 and the winding coil for transformation 4 are each a single component, it is difficult to reduce the size of the strobe and reduce the number of mounted components.

Moreover, it is difficult to reduce the size of the strobe and reduce the number of parts for the following reasons.
That is, the transformer winding coil 4 that is a trigger coil is a main target component for miniaturization, but a high voltage of several KV must be extracted from the output electrode of the secondary winding 43. Therefore, it is necessary to attach the output electrode of the secondary winding 43 at a sufficient distance from other electrodes in terms of withstand voltage. This makes it difficult to reduce the size of the transformer winding coil 4.

  In addition, a trigger capacitor 3 is used for the strobe, but this trigger capacitor 3 needs to satisfy the condition of withstand voltage of several hundred volts. For this reason, the overall outer dimensions of the trigger capacitor 3 are increased, and a relatively large occupied area is required even when the trigger capacitor 3 is mounted on the component mounting board of the strobe. That is, the mounting area of the trigger capacitor 3 is increased, and it is similarly difficult to reduce the size.

  Further, since the trigger capacitor 3 and the transformer winding coil 4 are separately assembled in the strobe component mounting board, the number of mounting steps increases. Further, since the trigger capacitor 3 and the transformer winding coil 4 are mounted in a state where a certain amount of space is secured, the mounting area is increased further, and accordingly, the component mounting area of the component mounting board is increased.

  Furthermore, if the current limiting resistor 1 is added in addition to the trigger capacitor 3 and the transformer winding coil 4, the mounting man-hours will increase, and it will be necessary to secure an empty space with other components. The component mounting area increases.

  Furthermore, in the assembly maker, the capacity of the trigger capacitor 3 is often selected when there is a marginal space on the component mounting board. As a result, it becomes difficult to obtain a constant trigger output voltage according to the capacity of the arbitrarily selected trigger capacitor 3, and when an excessive trigger output voltage is applied to the transformer winding coil 4, the transformer winding Leakage occurs between the windings 41 and 43 of the wire coil 4, and the trigger output voltage is mixed into other adjacent parts, resulting in problems such as disturbing electrical characteristics.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a circuit element for light source excitation that achieves integration of a plurality of components, and reduces the number of components, the mounting man-hours, and the component mounting area. And

  In order to solve the above problems, a circuit element for light source excitation according to the present invention includes a ceramic capacitor in which a plurality of ceramic chips having a predetermined outer dimension are stacked and charged with a predetermined voltage input from the outside, and the ceramic capacitor A sheet-shaped ferrite core laminated on one side or both sides, and a primary winding wound around a winding core in which the ceramic capacitor and the ferrite core are laminated, and a voltage charged to the ceramic capacitor is applied. A secondary winding wound around the winding core and induced by a current flowing through the primary winding by application of the charging voltage to generate a high trigger output voltage for exciting the light source; Is an integrated configuration.

  In the present invention, the ceramic capacitor and the ferrite core are wound as a core, and the primary side winding and the secondary side winding are wound around the winding core. It becomes possible to handle the wire coil as one integrated part, and it becomes unnecessary to provide an empty space between the parts. Therefore, it is possible to reduce the number of components, reduce the number of mounting steps, and reduce the component mounting area, and can sufficiently meet the demand for downsizing of digital cameras and mobile phones.

  Further, the light source excitation circuit element according to the present invention prints a resistor on one surface portion of the Ni ferrite core laminated on any one surface portion of the ceramic capacitor, and the printed resistor is The current limiting resistor element restricts the charging current to the ceramic capacitor.

  As a result, the integration of the ceramic capacitor, transformer winding coil and current limiting resistor element contributes to the reduction of parts more and more, and at the same time, it is possible to reduce the number of mounting steps and the part mounting area. .

  ADVANTAGE OF THE INVENTION According to this invention, the circuit element for light source excitation which can implement | achieve the reduction of a number of parts, the reduction of a mounting man-hour, and the reduction of a component mounting area by integrating several components can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a circuit configuration diagram of a strobe to which an embodiment of a light source excitation circuit element 10 according to the present invention is applied. In FIG. 8, the same parts as those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be given in FIG.

  The light source excitation circuit element 10 is connected to a common connection between the current limiting resistor 1 and the off thyristor 2 and is a ceramic capacitor corresponding to a trigger capacitor that charges a voltage supplied from a power transformer (not shown) in a steady state. 11 and, for example, a transformer winding coil 12 which is a winding for generating a high voltage constituting a strobe.

  The transformer winding coil 12 includes a Ni ferrite core 12a, a primary winding 12b having a predetermined number of turns wound around the ferrite core 12a, and a turn larger than the number of turns of the primary winding 12b in the ferrite core 12a. The secondary winding 12c is configured to take out a trigger output voltage that is a predetermined high voltage. The secondary winding 12c is connected between the high voltage electrode plate 6 disposed in the vicinity of the xenon tube 5 and the ground line. In FIG. 1, 13 is a capacitor terminal, 14 is a primary / secondary winding common terminal, and 15 is a high voltage output terminal.

  FIG. 2 is an exploded perspective view of the light source excitation circuit element 10 according to the present invention.

  In the ceramic capacitor 11, a capacitor electrode 11c of a metal plate is attached, for example, by spot welding or the like to a bipolar plate 11b of a ceramic capacitor body 11a in which ceramic chips having a predetermined outer dimension are laminated.

  As an example of manufacturing these multiple ceramic chips, for example, a powder obtained by solid-phase reaction by heating a mixed powder of barium carbonate and titanium dioxide is molded and fired to produce a ceramic having a predetermined outer dimension. It has excellent high dielectric constant, heat resistance and high frequency characteristics. Each ceramic chip is formed to have the same predetermined outer dimensions.

  Therefore, the ceramic capacitor 11 can be used as a multilayer ceramic capacitor having a required capacity by adjusting the number of laminated ceramic chips.

  And the Ni ferrite core 12a which is a magnetic material is laminated | stacked on the single side | surface part or both surface part of the ceramic capacitor 11. FIG. The Ni ferrite core 12a has a property having a high electric resistance value and is formed to have the same outer dimensions as the ceramic chip.

  As an example of manufacturing the Ni ferrite core 12a, the Ni ferrite core material 12a is produced by firing a powder of Ni ferrite core material and sintering it into a sheet shape and a square shape.

  Reference numerals 16a and 16b denote circuit element mounting members having a concave cross section formed of a plastic material or the like.

  One circuit element mounting member 16a is formed with an opening having a diameter so as to hold one end of the laminated body of the ceramic capacitor 11 and the Ni ferrite core 12a, and the opposite side to the opening is a closed surface portion. . A capacitor terminal 13 and a primary / secondary winding common terminal 14 shown in FIG. 1 are attached to the outside of the closed surface portion of the circuit element attaching member 16a at a predetermined distance. 17 is a metal plate 13a inserted from the capacitor terminal 13 into the circuit element mounting member 16a and protruding from one side of the mounting member 16a, and a capacitor electrode 11c of the ceramic capacitor 11 protruding from one side of the mounting member 16a. It is a soldering part to solder. Reference numeral 18 denotes a winding relay terminal for commonly connecting a primary side winding 12b and a secondary side winding 12cs, which will be described later. The winding relay terminal 18 and the primary / secondary winding common terminal 14 are connected by a metal plate inserted in the circuit element mounting member 16a.

  The connection between the ceramic capacitor 11 and the capacitor terminal 13 is not limited to the connection configuration described above, and can be connected by various connection means.

  The other circuit element mounting member 16b is formed with an opening having a diameter so as to hold the other end of the laminated body of the ceramic capacitor 11 and the Ni ferrite core 12a, and the opposite side to the opening is a closed surface portion. Yes. A hole 19 for projecting the other capacitor electrode 11c of the ceramic capacitor 11 is provided on one side surface of the circuit element mounting member 16b. A primary side winding 12b of the transformer winding coil 12 is connected to the capacitor electrode 11c protruding from the hole portion 19. Further, a high voltage output terminal 15 for connecting the primary winding 12b of the transformer winding coil 12 is attached to the upper end of the circuit element mounting member 16b in the figure.

  Note that the connection means between the ceramic capacitor 11 and the primary winding 12b of the transformer winding coil 12 and the attachment mode of the high-voltage output terminal 15 are not limited to the above-described contents, and various connection methods and attachment modes are available. Conceivable.

  FIG. 3A is a perspective view when a laminated body of the ceramic capacitor 11 and the Ni ferrite core 12a is integrally incorporated with the circuit element mounting members 13a and 13b.

  As is apparent from the figure, the laminated body of the ceramic capacitor 11 and the Ni ferrite core 12a is used as a winding core, and the primary winding 12b and the secondary winding 12c of the transformer winding coil 12 are wound around this winding core. Be dressed. As the winding order of the primary side winding 12b and the secondary side winding 12c, for example, the secondary side winding 12c that outputs a high voltage of several KV is wound on the lowermost layer, and the secondary side winding at the beginning of the winding is wound. The end of 12 c is connected to the high voltage output terminal 15. Subsequently, the primary winding 12b is wound. Note that insulating paper such as Mylar tape or Kapton tape is wound between the secondary winding 12c and the primary winding 12b.

  FIG. 3B is a diagram showing a finished product in which a primary winding 12b and a secondary winding 12c are wound around a laminate of a ceramic capacitor 11 and a Ni ferrite core 12a.

  Further, a support member (not shown) for attaching to the component attachment board is attached to one or both of the circuit element attachment members 16a and 16b.

  Next, the operation of the light source excitation circuit element 10 as described above will be described.

  After preparing a ceramic capacitor 11 having a predetermined capacity in which an arbitrary number of ceramic chips are stacked, chip-shaped Ni ferrite cores 12a are stacked on one or both sides of the multilayer ceramic capacitor 11, and this stacked body is used as a winding core. The single winding uniting the ceramic capacitor 11 corresponding to the trigger capacitor and the transforming winding coil 12 by winding the primary winding 12b and the secondary winding 12c of the transforming winding coil 12. Can be a part. Thereby, for example, mounting components and mounting man-hours to be mounted on a strobe component mounting board can be reduced.

  Further, if the number of mounted components is reduced, the mounting area of the components is reduced, and for example, the area of the component mounting board of the strobe is reduced, which greatly contributes to the miniaturization of the strobe. Therefore, it is possible to sufficiently cope with the recent trend of reducing the size and size of digital cameras and mobile phones.

  In addition, it is necessary to install the trigger capacitor and the transformer winding coil at a certain interval as in the conventional case. However, if it is not necessary to provide an empty space, the mounting area of the component, and consequently the mounting area of the component mounting board Can be reduced more and more.

  Further, the circuit element mounting members 16a and 16b are fitted so as to hold both end portions of the multilayer body of the multilayer ceramic capacitor 11 and the Ni ferrite core 12a, and divided into these two circuit element mounting members 16a and 16b. If the capacitor terminal 13, the primary / secondary winding common terminal 14 and the high-voltage high-voltage output terminal 15 are attached, a sufficient distance between the low-voltage system and the high-voltage system can be secured.

  Further, in the light source excitation circuit element 10 according to the present invention, the ceramic capacitor 11 and the transformer winding coil 12 are integrated, so that parts having uniform quality characteristics can be realized. It also solves the problem of capacitor selection.

Further, the reason why the trigger output voltage becomes constant by using the ceramic capacitor 11 as the light source excitation circuit element 10 according to the present invention will be described with reference to FIGS.
Now, in a general film capacitor having a capacity of 0.033 μF having no DC bias characteristic, when a voltage is applied while being varied in the range of 0 V to 350 V as shown in FIG. 4, the variable voltage is shown as indicated by a dotted line in the figure. No change in capacity occurs. The fact that the capacitance does not change with respect to the variable voltage means that when the trigger application voltage is gradually increased, the trigger output voltage gradually increases as shown in FIG. It is already well known that the trigger output voltage varies depending on the capacitance value of the trigger capacitor. FIG. 6 shows measurement data.

  On the other hand, in the ceramic capacitor 11 having a capacitance of 0.033 μF, when the applied voltage is increased as shown in FIG. 4, the capacitance decreases with a constant curve as shown by the solid line in the figure. Here, when the capacitance of the ceramic capacitor 11 decreases as the applied voltage increases, a constant trigger output voltage is extracted as shown by the solid line in FIG. Can do. That is, when the trigger application voltage increases, the capacitance decreases correspondingly, so that the trigger output voltage can be kept constant.

(Other embodiments)
(1) In the above-described embodiment, the ceramic capacitor 11 and the transformer winding coil 12 are integrated, but can be integrated including a current limiting resistor corresponding to a conventional current limiting resistor.

  Specifically, as shown in FIG. 7, a current limiting resistor 21 is printed and formed on one side of the Ni ferrite core 12a so as to have a predetermined resistance value, and one end of the current limiting resistor 21 is connected to a ceramic capacitor. 11 is connected to the ceramic capacitor body 11a, for example, and the external connection terminal 22 is taken out from the other end of the current limiting resistor 21. Then, the insulating sheet 23 is attached to the surface portion on which the current limiting resistance element 21 is printed and laminated on the surface portion of the ceramic capacitor 11.

  Thereby, it can be set as an integral structure including the ceramic capacitor 11, the coil | winding coil 12 for a transformation, and the current limiting resistive element 21. FIG. Therefore, it is possible to further reduce the number of components, and at the same time, it is possible to reduce the number of mounting steps and the component mounting area.

  In FIG. 7, the current limiting resistor 21 is formed on the surface portion side of the Ni ferrite core 12a facing the ceramic capacitor body 11a. However, the current limiting resistor 21 may be formed on the opposite surface portion side.

(2) The ceramic capacitor 11 has a DC bias characteristic in which the capacitance value decreases as the applied voltage increases. For example, the capacitance value changes in an optimal state in combination with the winding coil 12 for transformation. If the adjustment is made so that the DC bias characteristic is obtained, a constant trigger output voltage can always be taken out with respect to the increase of the applied voltage.

  The reason will be described. The trigger coil constituted by the transformer winding coil 12 is a transformer that operates at a high frequency, and the trigger output voltage varies depending on the applied voltage and the capacitance of the trigger capacitor. When a film capacitor whose capacitance value does not change at all with respect to the change of the applied voltage is used as the trigger capacitor, the trigger output voltage increases in proportion to the applied voltage. Further, even if the applied voltage is constant, the trigger output voltage rises in proportion to the capacitance value when the capacitance value to be used increases.

  On the other hand, the ceramic capacitor 11 has a property that the capacitance value decreases as the applied voltage is increased. This is called a DC bias characteristic. Although this is a drawback, it is desired to improve the DC bias characteristic and bring it closer to a film capacitor. The current trigger ceramic capacitor decreases in capacitance value as the applied voltage increases, but the slope of the trigger output voltage due to the increase in applied voltage is more gradual than the film capacitor. Normally, a xenon tube does not require a higher voltage if the minimum trigger output voltage required for light emission is present. Rather, when the trigger output voltage becomes higher than necessary, voltage discharge to the surrounding metal occurs, causing problems such as light emission failure and camera malfunction. Therefore, in the present invention, if the DC bias characteristics are adjusted from the constituent materials of the ceramic capacitor 11 and the transformer winding coil 12 serving as the trigger coil, and the capacitance value is appropriately reduced with respect to the increase of the applied voltage, it is always possible. It is possible to obtain a constant trigger output voltage.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

1 is a circuit configuration diagram of a strobe to which an embodiment of a light source excitation circuit element according to the present invention is applied. The disassembled perspective view which shows one Embodiment of the circuit element for light source excitation which concerns on this invention. The figure explaining the assembly state of the circuit element for light source excitation. The figure which compares the DC bias characteristic of the conventional general film capacitor and the ceramic capacitor of this invention. The figure which compares the trigger output voltage characteristic of the conventional general film capacitor and the ceramic capacitor of this invention. The figure which shows the measurement result of the characteristic data in FIG.4 and FIG.5. The disassembled perspective view explaining other embodiment of the circuit element for light source excitation which concerns on this invention. FIG. 2 is a general circuit configuration diagram of a conventional strobe.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Current limiting resistance, 2 ... Off silis etc. 5 ... Xenon tube (light source), 6 ... High voltage electrode plate, 7 ... Main capacitor, 10 ... Circuit element for light source excitation, 11 ... Ceramic capacitor, 12 ... Winding for transformer Coil, 12a ... Ni ferrite core, 12b ... Primary side winding, 12c ... Secondary side winding, 13 ... Capacitor terminal, 14 ... Primary / secondary winding common terminal, 15 ... High voltage output terminal, 16a, 16b ... Circuit Element mounting member, 21... Current limiting resistance element, 23.

Claims (2)

In the circuit element for light source excitation for exciting the light source,
A ceramic capacitor in which a plurality of ceramic chips having a predetermined external dimension are stacked and charged with a predetermined voltage input from the outside, a sheet-like Ni ferrite core stacked on one or both sides of the ceramic capacitor, and the ceramic A primary winding wound around a winding core in which a capacitor and the Ni ferrite core are laminated, and a voltage charged to the ceramic capacitor is applied; and wound around the winding core, by applying the charging voltage A circuit element for exciting a light source, comprising a secondary winding that is induced by a current flowing through the primary winding and generates a high trigger output voltage for exciting the light emitting source. The circuit element for light source excitation according to claim 1,
A current limiting resistor element that prints a resistor on one surface portion of the Ni ferrite core laminated on any one surface portion of the ceramic capacitor, and that regulates a charging current to the ceramic capacitor. A circuit element for exciting a light source.

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