JP2010008120A - Printed board for current detection, and current detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed board for current detection for simplifying a structure of a current detector. <P>SOLUTION: The printed board 1 for current detection for detecting an AC current flowing in a conductor for power transmission used as a transmission route of AC power includes: a penetration hole 401 penetrating the board; a shielding part 500 arranged outside the penetration hole 401, and formed of a through-hole; and coil-shaped wiring 10 arranged outside the shielding part 500, for detecting a current. When the shielding part 500 is provided on the printed board 1 for current detection, a shielding part having a complicated shape is not required to be formed on a casing of the current detector. Hereby, the structure of the casing of the current detector can be simplified. Since the shielding part of the printed board for current detection is formed of the through-hole, it can be formed easily, and consequently the structure of the current detector can be simplified. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a current detection printed circuit board used for detecting an alternating current flowing in a power transmission conductor used as an AC power transmission path, and a current detector using the current detection printed circuit board, for example. is there.

  For example, there are devices such as an impedance matching device and a high-frequency power supply device that detect the current and voltage of AC power and perform control using the detected current and voltage. As an example, an impedance matching device will be described.

  FIG. 17 is a block diagram of an example of a high-frequency power supply system in which the impedance matching device is used.

  This high-frequency power supply system is a system for performing processing such as plasma etching or plasma CVD on a workpiece such as a semiconductor wafer or a liquid crystal substrate, and includes a high-frequency power supply device 61, a transmission line 62, an impedance matching device 63, It is comprised by the load connection part 64 and the load 65 (plasma processing apparatus 65).

  The high-frequency power supply device 61 is a device for outputting high-frequency power and supplying it to the plasma processing device 65 serving as a load. The high-frequency power output from the high-frequency power supply device 61 is supplied to the plasma processing device 65 via a transmission line 62 made of a coaxial cable, an impedance matching device 63, and a load connection portion 64 made of a shielded copper plate. In general, this type of high-frequency power supply 61 outputs a high-frequency power having a frequency in the radio frequency band (for example, a frequency of several hundred kHz or more, although the upper limit is not strictly determined but is generally 1 GHz or less). .

  The plasma processing apparatus 65 is an apparatus for processing (etching, CVD, etc.) a wafer, a liquid crystal substrate, and the like.

  The impedance matching device 63 includes a matching circuit configured by a variable impedance element (for example, a variable capacitor, a variable inductor, etc.) not shown in the figure, and impedance matching is performed between the high frequency power supply device 61 and the load 65. And a control function for changing the impedance of the variable impedance element in the matching circuit.

  In order to perform such control, a current detector that detects a high-frequency current output from the high-frequency power supply device 61 and a voltage that detects a high-frequency voltage between the input terminal 63a of the impedance matching device 63 and the matching circuit. Detectors are provided, and information such as traveling wave power and reflected wave power is obtained using the current and voltage detected by these detectors. Then, using the obtained information, the impedance of the variable impedance element is controlled so as to perform impedance matching.

  FIG. 18 is a schematic circuit diagram of the current detector 80 and the voltage detector 90 provided between the input terminal of the impedance matching device 63 and the matching circuit 67. As shown in FIG. 18, a power transmission conductor 66 (for example, rod-shaped copper) serving as a power transmission path is provided from the input end 63 a to the matching circuit 67. A current detector 80 and a voltage detector 90 are provided in the middle of the power transmission conductor 66.

  The current detector 80 includes a current transformer unit 81, output wirings 82 and 83 of the current transformer unit 81, a current conversion circuit 84, and an output wiring 85 of the current conversion circuit 84. In the current detector 80, a current corresponding to the alternating current flowing through the power transmission conductor 66 flows through the current transformer 81. This current is input to the current conversion circuit 84 via the output wirings 82 and 83, converted to a predetermined voltage level, and output from the output wiring 85 of the current conversion circuit 84.

  The voltage detector 90 includes a capacitor unit 91, an output wiring 92 of the capacitor unit 91, a voltage conversion circuit 93, and an output wiring 94 of the voltage conversion circuit 93. In the voltage detector 90, a voltage corresponding to the AC voltage generated in the power transmission conductor 66 is generated in the capacitor unit 91. This voltage is input to the voltage conversion circuit 93 via the output wiring 92, converted to a predetermined voltage level, and output from the output wiring 94 of the voltage conversion circuit 93.

  Then, as described above, information such as traveling wave power and reflected wave power is obtained using the current and voltage detected by the current detector 80 and the voltage detector 90.

  Further, the current detector 80 and the voltage detector 90 as described above can also be used for other devices such as the high frequency power supply device 61. For example, in the case of a high-frequency power supply device, it is provided at the output end of the high-frequency power supply device 61 and used to detect a current and a voltage necessary for controlling the output traveling wave power to be a set value.

  Further, the current and voltage at the output terminal 63b of the impedance matching device or the input terminal of the load 65 may be detected, and the detected current and voltage may be used for control and analysis.

FIG. 19 is a circuit diagram when the current detector 80 and the voltage detector 90 are provided between the matching circuit in the impedance matching device and the output terminal.
As shown in FIG. 19, the current detector 80 and the voltage detector 90 are provided in the middle of the power transmission conductor 68 between the matching circuit 67 and the output end 63b in the impedance matching device, and The current and voltage at the output terminal 63b may be detected.

  In FIG. 19, the same components as those in the circuit diagram shown in FIG. However, since there is a difference in current and voltage between the input end 63a and the output end 63b of the impedance matching device, the current detector 80 and the voltage detector 90 have structural differences from the viewpoint of withstand current and withstand voltage. is there. However, in FIG. 19, the same reference numerals are used without considering these differences. For example, normally, the output end 63b has a higher current and voltage than the input end 63a of the impedance matching device. Therefore, when the current detector 80 and the voltage detector 90 are provided at the output end 63b of the impedance matching device, the power transmission conductor 68 is a conductor having a larger diameter than when the current detector 80 and the voltage detector 90 are provided at the input end 63a of the impedance matching device. In addition, it is necessary to increase the insulation distance by increasing the thickness of the insulator 69 covering the outer periphery of the power transmission conductor 68. However, the circuit diagram shown in FIG. 19 does not consider these differences for convenience.

  Further, as shown in FIG. 19, when used in an impedance matching device, a detector for detecting current and voltage information necessary for impedance matching is separately required on the input side of the impedance matching device. The illustration is omitted.

  Examples of the current detector 80 described above include, for example, the current detection printed circuit board 6 shown in FIGS. 20 and 21, and the voltage detector 90 corresponds to the voltage detection print shown in FIG. There is a substrate 7.

FIG. 20 is a diagram showing the current detection printed circuit board 6.
20A is a plan view of the current detection printed circuit board 6 (viewed from above), and FIG. 20B is a part of FIG. 20A (indicated by a dotted line). (C) is an enlarged schematic view, in order to simplify the illustration of FIG. (B), FIG. The wiring of the printed circuit board 6 for current detection when the figure (c) is seen from the side is shown in figure. For the sake of explanation, the wiring shown in FIG. 4D is shown through a portion that is not normally visible.

  As shown in FIGS. 20A to 20D, the current detection printed circuit board 6 is provided with a through hole 101 penetrating the circuit board, and a wiring 10 (hereinafter referred to as a coil) formed in a coil shape around the hole 101. (Referred to as a wiring 10). The coil-shaped wiring 10 is formed in a coil shape having both end portions 10a and 10b by alternately connecting the front surface 121 and the back surface 122 of the substrate while penetrating the substrate. A portion of the wiring that penetrates the substrate is formed by a through hole 11, and wiring on the front surface and the back surface of the substrate is formed by pattern wirings 12 and 13.

  20B to 20C, the portion indicated by a dotted line indicates the pattern wiring on the back surface of the substrate, but is indicated by a dotted line because it is transmitted. Further, output wirings 21 and 22 are connected to both end portions 10 a and 10 b of the coil-shaped wiring 10. This output wiring is connected to the output terminals 23 and 24.

  In the case of this example, since the substrate has a double-sided structure (hereinafter referred to as a double-sided substrate), pattern wiring is formed on the front surface layer and the back surface layer of one insulator portion 110.

  In the case of the current detection printed circuit board 6 as shown in FIG. 20, when the power transmission conductor 66 through which an alternating current flows is arranged so as to pass through the inside of the through hole 101, a coil-like shape is generated by electromagnetic induction. A current flows through the wiring 10. That is, the printed circuit board can have a current transformer function. In other words, a current transformer can be formed on the current detection printed circuit board 6.

  Accordingly, the portion of the coil-shaped wiring 10 corresponds to the current transformer portion 81 in the circuit diagrams shown in FIGS.

FIG. 21 is a diagram illustrating another example of the printed circuit board 6 for current detection.
21A is a plan view of the current detection printed circuit board 6, and FIG. 21B is an enlarged schematic view of a portion (B portion surrounded by a dotted line) of FIG. 21A. (C) is a diagram developed in a straight line in order to simplify the illustration of FIG. (B). FIG. (D) is a side view of FIG. (C). FIG. 4E shows the wiring of the current detection printed circuit board 6 from the side, centering on the output wiring 21 and the like. It is. Note that the wiring shown in FIG. 21 is shown through a portion that is not normally visible for the sake of explanation. For the sake of convenience, the same reference numerals as those in FIG. 1 are used for the current detection printed circuit board 6, the through holes 11, the pattern wirings 12 and 13, and the like.

  The current detection printed circuit board 6 shown in FIG. 21 is basically the same as the current detection printed circuit board 6 shown in FIG. 1 except that the circuit board has a multilayer structure and the coil-shaped wiring 10 is inside. It is formed between the layers.

  Note that in this specification, an insulator portion constituting a multilayer structure substrate (hereinafter referred to as a multilayer substrate) is shown in order from the top of the drawing in the order of a first insulator portion, a second insulator portion, and a third insulator. Part, ... and so on. In addition, the conductor layers formed between the insulator portions of the substrate are called the first conductor layer, the second conductor layer, the third conductor layer,... In order from the top of the drawing. A conductor layer formed on the surface of the substrate is referred to as a surface layer, and a conductor layer formed on the back surface of the substrate is referred to as a back layer.

  Since the double-sided board has two layers, a front surface layer and a back surface layer, it can be said to be a multilayer board. However, since there is only one insulator portion, there is no conductor layer formed between each insulator portion of the substrate. It is a form.

  In the example of FIG. 21, since the insulator part of the substrate is composed of three insulator parts of the first insulator part 111, the second insulator part 112, and the third insulator part 113, A first conductor layer 131 is formed between the insulator part 111 and the second insulator part 112, and a second conductor layer 132 is formed between the second insulator part 112 and the third insulator part 113. Yes. A surface layer can be formed on the surface 121 of the substrate (the surface above the first insulator portion). In addition, although a back surface layer can be formed on the back surface 122 (the surface below the third insulator portion) of the substrate, the back surface layer of the substrate is not provided in the example of FIG.

  Therefore, in the case of FIG. 21, the coiled wiring 10 is formed between the first conductor layer 131 and the second conductor layer 132. Therefore, the coil-like wiring 10 can be structured so that it cannot be seen from the outside of the substrate. Also in such a case, the portion of the coiled wiring 10 corresponds to the current transformer portion 81 in the circuit diagram shown in FIG.

  Further, as shown in FIG. 21E, the output wiring 21 of the coiled wiring 10 includes a pattern wiring 21a connected to one end 10a of the coiled wiring 10 formed in the first conductor layer 131, and a through wiring. The hole 21b and the pattern wiring 21c formed on the surface of the substrate are formed and connected to the output terminal 23. Since the output wiring 22 of the coiled wiring 10 is the same, the description thereof is omitted.

FIG. 22 is a diagram showing the voltage detection printed circuit board 7.
22A is a plan view of the voltage detection printed circuit board 7, and FIG. 22B is an enlarged schematic view of a part (part C surrounded by a dotted line) of FIG. (C) is a diagram developed in a straight line in order to simplify the illustration of FIG. (B). FIG. (D) is a side view of FIG. (C). The wiring of the current detection printed circuit board 6 is shown in the figure. For the sake of explanation, the wiring shown in FIG. 4D is shown through a portion that is not normally visible.

  As shown in FIGS. 22A to 22D, the voltage detection printed circuit board 7 is provided with a through hole 201 penetrating the board, and a ring-shaped wiring 30 is provided around the through hole 201. The ring-shaped wiring 30 is formed by providing a plurality of through-holes 31 penetrating the substrate around the through-hole 201 and providing pattern wirings 32 and 33 so as to connect the through-hole portions to the front and back surfaces of the substrate. It has been done. For this purpose, a through hole is provided between the pattern wirings 32 and 33 on the front surface and the back surface of the substrate. Therefore, the through hole is formed so as to have substantially the same thickness as that of the substrate. Become.

  22B to 22C, the pattern wirings 32 and 33 on the front surface and the back surface of the substrate are overlapped. Further, the output wiring 40 is connected to the ring-shaped wiring 30. This output wiring is connected to the output terminal 41.

  In this example, since the substrate has a double-sided structure (hereinafter referred to as a double-sided substrate), pattern wiring is formed on the front surface layer and the back surface layer of one insulator portion 210.

  When the voltage detection printed circuit board 7 as shown in FIG. 22 is used, when the power transmission conductor 66 in which an AC voltage is generated is disposed so as to pass inside the through hole 201, the ring-shaped wiring 30. However, the power transmission conductor 66 functions as a capacitor electrode paired with a portion facing the ring-shaped wiring 30. That is, the printed circuit board can have a function as an electrode of a capacitor. Therefore, the portion of the ring-shaped wiring 30 corresponds to the electrode 91b of the capacitor portion in the circuit diagrams shown in FIGS.

FIG. 23 is a schematic external view of the current / voltage detector 5.
23A is a schematic external view of the current / voltage detector 5 in a three-dimensional view, and FIG. 23B is a schematic view seen from the side of a conductive housing. FIG. 2C is an external view, and FIG. 2C is a view when the housing of FIG. 2B is removed.

  As shown in FIG. 23A, the current / voltage detector 5 has a structure in which the power transmission conductor 66 can penetrate the casing. Note that the power transmission conductor 66 and the insulator 69 therearound are not included in the configuration of the current / voltage detector 5, but are shown in the figure because they are necessary for explanation. The insulator 69 is for insulating the power transmission conductor 66 and the current / voltage detector 5. For this purpose, the length of the insulator 69 may be shorter than that shown in the figure, but for simplicity of the drawing, it is as shown in FIG. In this regard, the same applies to the other drawings.

  Further, as shown in FIG. 23C, the current detection printed circuit board 6 and the voltage detection printed circuit board 7 are accommodated in the housing. For this purpose, the current flowing through the power transmission conductor 66 passing through the housing is detected by the current detection printed circuit board 6, and the voltage generated in the power transmission conductor 66 is detected by the voltage detection printed circuit board 7. It has a structure that can.

  23B, the left part of the current / voltage detector 5 corresponds to the current detector 3, and the right part corresponds to the voltage detector 4. In the example shown in FIG. The housing is made of a conductor such as aluminum. The current detector 3 corresponds to the voltage detector 80 shown in FIGS. 18 and 19, and the voltage detector 4 corresponds to the voltage detector 90 shown in FIGS. 18 and 19.

  24 is a schematic configuration diagram of the current / voltage detector 5 shown in FIG. 24A is a schematic configuration diagram of the current / voltage detector 5, and FIG. 24B is a schematic diagram when the components shown in FIG. 24A are assembled. . In FIG. 24, the shape of each component is only an outline. For example, the housing and the substrate are provided with a through hole for allowing the electric power transmission conductor 66 to pass therethrough and an opening for causing a magnetic flux to act, but these are not shown. Moreover, in FIG. 24, the outline of the part which cannot be seen from the outer side is shown with the dotted line.

  As shown in FIG. 24A, the current / voltage detector 5 includes a housing main body 330, a current detection printed circuit board 6 fixed to the housing main body 330, a voltage detection printed circuit board 7, and a current detection unit. It is comprised by the lid | cover 331 and the cover 332 for voltage detection parts. Of course, parts such as screws and screws for fixing them are also included, but these parts are regarded as a part of the constituent elements and are not shown for the sake of simplicity. When each component is fixed to the housing body 330 as shown by the arrows shown in FIG. 24A, the current detection printed circuit board 6 and the voltage detection print are shown in FIG. 24B. Each of the substrates 7 is fixed inside the housing main body 330, and a lid is provided so as to cover the current detection printed circuit board 6 and the voltage detection printed circuit board 7, respectively.

  As described above, the casing main body 330 is common to the current detection printed circuit board 6 and the voltage detection printed circuit board 7, but if the side on which the current detection printed circuit board 6 is fixed is a surface, the voltage detection print board 6 is used. Since the substrate 7 is fixed to the back surface, the current detection printed circuit board 6 and the voltage detection printed circuit board 7 are generally accommodated in independent spaces.

FIG. 25 is a cross-sectional view of the current / voltage detector 5 shown in FIG.
FIG. 26 is a diagram illustrating the housing body 330 in a three-dimensional manner. FIG. 26A is a diagram viewed from the side where the current detection printed circuit board 1 is fixed, and FIG. It is the figure seen from the side to which the printed circuit board 2 for voltage detection is fixed.

  As shown in FIGS. 25 to 26, since the through-hole 303 and the recesses 311, 312, 321, and 322 are provided in the housing main body 330, the power transmission conductor 66 and the power transmission conductor 66 are provided. The current detection printed circuit board 6 and the voltage detection printed circuit board 7 can be accommodated in the housing.

  FIG. 27 is a diagram showing an example in which the current detection printed circuit board 6 and the voltage detection printed circuit board 7 are housed in separate housings, and are made into independent current detectors 3 and voltage detectors 4, respectively. .

  FIG. 28 is a cross-sectional view of the current detector 3 shown in FIG. FIG. 28 corresponds to the cross section of the current / voltage detector 5 shown in FIG. 25 with the lower part corresponding to the voltage detector 4 removed. For this reason, the casing main body 310 for the current detector 3 is used, but the others are the same as in FIG.

  As shown in FIGS. 27 and 28, the current detector 3 and the voltage detector 4 can be made independent. In this case, when the current detector 3 and the voltage detector 4 are superposed on each other, it becomes the same as that in which the casing body is integrally formed.

JP 2007-225588 A

  By the way, the voltage detection printed circuit board 7 side of the casing body 330 of the current / voltage detector 5 has a relatively simple shape. However, the first shielding portion 313 is provided around the through hole on the current detection printed circuit board 6 side of the housing body 330, and has a complicated shape. And it turns out that the opening part 317 is formed of the clearance gap between the 1st shielding part 313 and the lid | cover 301 for electric current detection parts. The reason for this will be described below.

  When a current flows through the power transmission conductor 66, a magnetic flux is generated around the conductor. When this magnetic flux acts on the coil-shaped wiring 10 provided on the current detection printed board 6, a current flows through the coil-shaped wiring 10. Then, by detecting the current flowing through the coiled wiring 10, the current flowing through the power transmission conductor 66 is known. For this reason, if the gap between the power transmission conductor 66 and the current detection printed circuit board 6 is shielded by a conductive casing, the magnetic flux does not act on the current detection printed circuit board 6, so that the current is detected. become unable. Therefore, the housing is provided with an opening 317 for taking magnetic flux generated around the conductor into the housing.

  More specifically, when a current flows through the power transmission conductor 66, not only a magnetic flux is generated but also an electric field is generated around the conductor. However, the electric field adversely affects the detection of current by the current detection printed circuit board 6. Therefore, the first shielding part 313 is provided between the power transmission conductor 66 and the current detection printed circuit board 6. That is, by arranging a conductor between the power transmission conductor 66 and the current detection printed board 6, the housing has a function of weakening the influence of the electric field.

  However, in order to form the 1st shielding part 313 and the opening part 317, it is necessary to make it a complicated shape as shown in the figure. Therefore, for example, there has been a problem that the manufacturing cost of the housing is increased. The same applies to the case of the current detector 3 shown in FIG.

  The present invention has been conceived under the above circumstances, and an object thereof is to provide a printed circuit board for current detection for simplifying the structure of a current detector. As a result, it aims at providing the electric current detector of a simple structure.

The printed circuit board for current detection provided by the first invention is
A current detection printed circuit board for detecting an alternating current flowing in a power transmission conductor used as an AC power transmission path,
A through hole penetrating the substrate;
A shielding part disposed outside the through hole and formed by the through hole;
Wiring for performing current detection arranged outside the shielding part;
It is characterized by having.

The printed circuit board for current detection provided by the second invention is
The shielding portion is formed by arranging a plurality of through holes in a substantially circular shape.

The printed circuit board for current detection provided by the third invention is
The shielding portion is formed by arranging a plurality of through holes in a substantially circular shape and at least double.

The current detector provided by the fourth invention is:
In a current detector for detecting an alternating current flowing in a power transmission conductor used as a transmission path for alternating current power,
A current detection print including a through hole penetrating the substrate, a shielding part disposed outside the through hole and formed by the through hole, and a wiring for performing current detection arranged outside the shielding part A substrate,
A housing made of a conductor configured to fix the current detection printed circuit board inside and provide a through hole for allowing the power transmission conductor to pass therethrough so as to cover the current detection printed circuit board; ,
It is characterized by having.

The current detector provided by the fifth invention is
The shield part of the current detection printed circuit board is formed by arranging a plurality of through holes in a substantially circular shape.

The current detector provided by the sixth invention is:
The shielding part of the current detection printed circuit board is formed by arranging a plurality of through holes in a substantially circular shape and at least double.

The current detector provided by the seventh invention is
By the shielding part of the printed circuit board for current detection and the housing,
A shielding part including a part that is not partially shielded is formed between the through hole and the wiring of the printed circuit board for current detection.

The current detector provided by the eighth invention is
The unshielded portion of the shielding portion of the current detection printed board is provided between the front surface and the back surface of the substrate.

The current detector provided by the ninth invention is
The non-shielding portion of the shielding portion of the current detection printed circuit board is provided between the substrate and the housing.

The current detector provided by the tenth invention is
The case is characterized in that the case includes a case main body that fixes the printed circuit board for current detection and a lid that covers the case main body.

The current detector provided by the eleventh invention is
The AC power is AC power having a frequency in a radio frequency band.

  Further, the wiring of the current detection printed circuit board is formed in a coil shape having both end portions by alternately connecting the uppermost layer and the lowermost layer of the substrate while penetrating between the uppermost layer and the lowermost layer of the substrate. At least one wiring formed, or / and at least one wiring formed in a coil shape having both ends by alternately connecting the uppermost layer and the lowermost layer of the penetrating portion while penetrating between the layers of a part of the substrate It may consist of

According to the present invention, since the shielding part can be provided on the current detection printed circuit board, it is not necessary to form a shielding part having a complicated shape in the casing of the current detector. Therefore, the structure of the casing of the current detector can be simplified.
Moreover, since the shielding part of the current detection printed circuit board is formed by the through hole, it can be easily formed. Therefore, the structure of the current detector can be simplified.

  Hereinafter, details of the present invention will be described with reference to the drawings.

(1) Print board for current detection FIG. 1 is a diagram showing an example of a print board 1 for current detection according to the present invention.
1A is a plan view of the current detection printed circuit board 1 (viewed from above), and FIG. 1B is a part (a dotted line) of FIG. (C) is an enlarged schematic view, and FIG. (C) is a diagram developed linearly to simplify the illustration of FIG. (B), and (d) of FIG. It is the schematic which looked at a part of the figure (c) from the side. FIG. 4E is an EE cross-sectional view of FIG.

As shown in FIG. 1A, the current detection printed circuit board 1 is provided with a through hole 401 penetrating the board, and a shielding part 500 having a shielding function is formed outside thereof. The shielding unit 500 will be described later.
The coil-shaped wiring 10 described above is formed outside the shielding unit 500. In addition, output wirings 21 and 22 are connected to the coiled wiring 10. Further, output terminals 23 and 24 are connected to the output wirings 21 and 22, respectively.

  The coiled wiring 10 is the same as that shown in FIG. That is, in FIG. 20, the coiled wiring 10 is formed around the through hole 101, but in FIG. 1, there is a difference that it is formed outside the shielding part 500, but it functions as a current transformer. The point is the same. The output wirings 21 and 22 and the output terminals 23 and 24 are the same as those shown in FIG.

  Thus, although the coil-shaped wiring 10 etc. have a different point from what was shown in FIG. 20, the basic composition is the same. Therefore, detailed description of the coiled wiring 10 and the like is omitted. For ease of explanation, the same reference numerals are used for the same functions as those described above.

  Thus, since the current detection printed circuit board 1 includes the coil-like wiring 10, it has a current detection function.

Next, the shielding unit 500 will be described.
As shown in FIGS. 1B to 1C, the shielding part 500 is formed by arranging a plurality of through holes 501 and 502 in a substantially circular shape. More specifically, it is formed by arranging a plurality of through holes in a substantially circular shape and at least double.
In the illustrated example, a plurality of through holes 501 are arranged in a substantially circular shape inside the shielding portion 500 (on the side close to the through hole 401), and a plurality of through holes 502 are arranged in a substantially circular shape outside the shielding portion 500. . Further, the through hole 501 and the through hole 502 are shifted from each other. Therefore, when the shielding unit 500 is viewed from the side, the through hole 501 and the through hole 502 are overlapped, and the gap is eliminated. Therefore, the electric power transmission conductor 66 has a shielding function against an electric field generated when the electric power transmission conductor 66 is disposed so as to pass through the inside of the through hole 401. Moreover, since the through hole can be easily formed when producing a printed circuit board, it is easy to form the shielding portion 500.

  In addition, as shown in FIG. 10 etc. mentioned later, the shielding part 500 needs to be connected to a housing | casing. Therefore, the current detection printed circuit board 1 alone does not have the shielding function of the shielding part 500, but the structure of the current / voltage detection printed circuit board is, as described in FIG. It is necessary to provide a shielding portion 500 between the wiring 10 and the wiring 10.

  In FIG. 1, the shielding part 500 is formed with double through holes. However, when the through holes are arranged in three or more layers, the shielding part 500 is viewed from the side according to the above concept. What is necessary is just to make it the gap of the through hole which forms 500 disappear.

  FIG.1 (d) is the schematic which looked at the several through-hole 501 shown in FIG.1 (c) from the side surface. As shown in FIG. 1D, the current detection printed circuit board 1 is a multilayer board. As shown in FIG. 1D, the through hole 501 is divided into an upper through hole 501a and a lower through hole 501b so as not to penetrate the substrate. Although not shown in FIG. 1D, the through hole 502 side is similarly divided into an upper through hole 502a and a lower through hole 502b so as not to penetrate the substrate. . That is, the shielding part 500 is provided with a part that is not shielded in a part between the front surface and the back surface of the substrate. This state is also clear from FIG. 1E is a cross-sectional view taken along the line E-E in FIG. 1A, and is a cross-sectional view schematically showing the state of the shielding portion 500 and the like.

  As described above, the shielding portion 500 is formed in a substantially circular shape, but is not limited thereto, and may be provided between the through hole 401 and the coiled wiring 10. Therefore, for example, it is possible to make it oval, or it is possible to make part of it linear. However, if the through hole 401 and the coiled wiring 10 are substantially circular, it is preferable that the shielding part 500 is also substantially circular because there is a merit that the area can be reduced.

FIG. 2 is a view showing another example of the printed circuit board 1 for current detection according to the present invention.
2A is a plan view of the current detection printed circuit board 1 (viewed from above), and FIG. 2B is a part (a dotted line) of FIG. (C) is an enlarged schematic view, in order to simplify the illustration of FIG. (B), and (d) in FIG. It is the schematic which looked at a part of the figure (c) from the side. FIG. 4E is a cross-sectional view taken along line GG in FIG.

The printed circuit board 1 for current detection shown in FIG. 2 is different from that shown in FIG.
Specifically, the coil-like wiring 10 in FIG. 2 is the same as that shown in FIG. The shielding unit 500 is the same as that shown in FIG. Therefore, the detailed description about these is abbreviate | omitted. For ease of explanation, the same reference numerals are used for the same functions as those described above.

  As in FIG. 1, the basic configuration of the coiled wiring 10 and the like is the same, although there is a difference from that shown in FIG. 21. The coiled wiring 10 functions as a current transformer.

  Thus, it is possible to use other forms of the coiled wiring 10 described so far. Further, for example, as shown in FIGS. 5 to 8 of Patent Document 1 (Japanese Patent Laid-Open No. 2007-225588), it is also possible to use a double coiled wiring 10.

(2) Current Detector FIG. 3 is a schematic external view showing the current detector 3 according to the present invention three-dimensionally.

  As shown in FIG. 3, the current detector 3 has a structure in which the power transmission conductor 66 can pass through the housing, as in the conventional case. Note that the power transmission conductor 66 and the insulator 69 therearound are not included in the configuration of the current detector 3, but are shown in the figure because they are necessary for explanation. The insulator 69 is used to insulate the power transmission conductor 66 from the current detector 3. For this purpose, the length of the insulator 69 may be shorter than that shown in the figure, but is shown in FIG. In this regard, the other drawings are the same (for example, FIG. 10). The housing is made of a conductor such as aluminum.

  FIG. 4 is a schematic configuration diagram of the current detector 3 shown in FIG. In FIG. 4, the shape of each component is only an outline. For example, a housing or a substrate is provided with a through hole or the like for allowing the electric power transmission conductor 66 to pass therethrough, but these are not shown.

  As shown in FIG. 4, the current detector 3 includes a housing main body 300, a current detection printed circuit board 1 fixed to the housing main body 300, and a lid 301. Of course, parts such as screws and screws for fixing them are also included, but these parts are regarded as a part of the constituent elements and are not shown for the sake of simplicity. The lid 301 is a part of the casing and is made of a conductor such as aluminum. 4, when each component is fixed to the housing body 300, the current detection printed circuit board 1 is fixed inside the housing body 300, and the current detection printed circuit board 1 is fixed. The lid is covered to cover.

Next, the part excluding the lid 301 will be specifically described.
FIG. 5 is a diagram of the housing body 300. 5A is a cross-sectional view of the side surface of the housing body 300, and FIG. 5B is a plan view (viewed from the side on which the current detection printed circuit board 1 is fixed). is there.

  FIG. 6 is a diagram illustrating the housing body 300 in a three-dimensional manner.

  FIG. 7 is a diagram when the current detection printed circuit board 1 is attached to the housing body 300 without the lid 301 attached. The current detection printed circuit board 1 is, for example, the same as that shown in FIG.

  As shown in FIGS. 5 to 7, since the through-hole 303 and the recesses 311 and 312 are provided in the casing body 300, the power transmission conductor 66 and the insulator covering the power transmission conductor 66 are provided. 69 and the current detection printed circuit board 1 can be accommodated inside the housing.

  The first housing shielding part 306 is a part of the housing body 300 and is provided to be connected to the shielding part 500 when the current detection printed circuit board 1 is attached to the housing body 300. ing. That is, the first housing shielding part 306 is formed in a substantially circular shape in accordance with the shape of the shielding part 500. Of course, as described above, when the shielding part 500 is not substantially circular, it may be shaped in accordance with the shape of the shielding part 500. The first housing shield 306 may be detachable by, for example, screwing, but in this case as well, the first housing shield 306 is a part of the housing body 300. The first housing shield 306 is made of a conductor such as aluminum, as with the housing body 300.

Although not shown in FIGS. 5 to 7, as shown in FIG. 10 and the like which will be described later, the lid 301 also has a second housing shielding portion 307 similar to the first housing shielding portion 306. Is provided. Specifically, the cover 301 is provided to be connected to the shielding unit 500 when the lid 301 is attached to the housing body 300 after the current detection printed circuit board 1 is attached to the housing body 300. That is, the second casing shielding part 307 is formed in a substantially circular shape in accordance with the shape of the shielding part 500.
Note that the second housing shielding part 307 may be detachable by, for example, screwing, but in this case, the second housing shielding part 307 is a part of the lid 301. The second housing shielding part 307 is made of a conductor such as aluminum. Functions of the shielding unit 500 and the like will be described later.

  Further, four substrate fixing portions 315 are provided at the four corners of the recess 311, and the current detection printed circuit board 1 is fixed to these portions. This is because the current detection printed board 1 is floated with respect to the bottom surface of the recess 311 so that the wiring provided on the current detection printed circuit board 1 does not come into contact with the housing (the shield 500 is not a wiring). It is.

  For example, when the coil-like wiring 10 of the current detection printed circuit board 1 is not formed on the back surface layer of the substrate as shown in FIG. 2, the substrate fixing portions 315 provided at the four corners of the recess 311 can be eliminated, and the recess The heights of the bottom surfaces of 311 and the recess 312 can be made the same. In addition, the first housing shielding unit 306 is not necessary.

  FIG. 8 is a diagram three-dimensionally illustrating the housing body 300 when the substrate fixing part 315 is not provided. If it is made like this FIG. 8, the structure of the housing body 300 can be simplified.

  In addition, since the power transmission conductor 66 having a cylindrical shape (circular in cross section) is usually used, the through hole 303 provided in the housing body 300 is also circular in accordance therewith. The through hole 401 of the current detection printed circuit board 1 is circular.

Next, the current detection printed circuit board 1 will be described.
The coil-shaped wiring 10 of the current detection printed circuit board 1 is the same as that described with reference to FIG. 1, but the output wirings 21 and 22 are connected to the current conversion circuit 51 while being the pattern wiring. The current conversion circuit 51 corresponds to the current conversion circuit 84 shown in FIGS.

  Therefore, unlike the current detection printed circuit board 1 described with reference to FIG. 1, the coil-shaped wiring 10 and the current conversion circuit 51 are provided on the same circuit board. That is, the shape of the printed circuit board 1 for current detection is different from that in FIG.

  The output wiring 52 connected to the current conversion circuit 51 extends outside the housing through the wiring opening 316. It is assumed that the current conversion circuit 51 has an output terminal for connecting the output wiring 52. Further, the output wiring 52 may be a part of the pattern wiring or may be a wiring other than the pattern wiring.

  The housing body 300 is provided with a third housing shield 308 at a position corresponding to the space between the coil-like wiring 10 of the current detection printed circuit board 1 and the current conversion circuit 51. Therefore, the current detection printed circuit board 1 has a shape in which the substrate width is narrowed in the middle of the substrate in accordance with the third housing shielding portion 308.

  In this example, the third housing shielding part 308 has a function of shielding a part between the space where the coil-shaped wiring 10 is located and the space where the current conversion circuit 51 is located.

FIG. 9 is an example of an application example of the third housing shielding unit 308.
As shown in FIGS. 5 to 8, since the gap is generated in the output wiring portion only with the third housing shielding portion 308 of the housing body 300, shielding may not be sufficiently performed. In that case, as shown in FIG. 9A, a cover 317 that fills the gap in the lid 301 may be provided. By doing so, the gap between the portions of the output wiring is almost eliminated, and the shielding effect is enhanced. Further, as shown in FIG. 9B, a shielding part 318 may be provided on the lid 301 instead of the third housing shielding part 308.

Next, the shielding function of the shielding unit 500 will be described.
FIG. 10 is an example of a cross-sectional view when the current detection printed circuit board 1 is accommodated in a housing. FIG. 10 schematically shows, for example, the state of the HH section in a state where the lid 301 is attached to the one shown in FIG.

  Considering the case where the shielding unit 500 does not exist, since the power transmission conductor 66 and the coiled wiring 10 are not shielded, the magnetic flux necessary for current detection acts on the coiled wiring 10. . At the same time, the coiled wiring 10 is affected by the electric field. However, since the coiled wiring 10 is not preferably affected by the electric field as described above, it causes a reduction in the accuracy of current detection. For this reason, it is necessary to devise a technique for reducing the influence of the electric field on the coiled wiring 10 and improving the accuracy of current detection.

  Therefore, the shielding unit 500 and the shielding units above and below the shielding unit 500 (the first housing shielding unit 306 and the second housing shielding unit 307) are provided, and the power transmission conductor 66 and the coiled wiring 10 are provided. Is shielded as much as possible. Of course, since it is necessary to cause the magnetic flux necessary for current detection to act on the coiled wiring 10, a portion that is not completely shielded but not shielded is provided.

  From the viewpoint of shielding, it is preferable to make the unshielded portion as small as possible. However, a specific design may be made in consideration of current detection by the coiled wiring 10. In any case, it is possible to reduce the influence of the electric field on the coiled wiring 10 and to cause the magnetic flux necessary for current detection to act on the coiled wiring 10 as compared with the case where the shielding part 500 does not exist. Can do.

  Further supplementally, as can be seen from the above description, the shielding unit 500 is connected to the first housing shielding unit 306 and the second housing shielding unit 307 above and below the shielding unit 500, thereby Electrically connected. Thereby, the shielding part 500 has a shielding function.

  Note that the shield 500 and the ring-shaped wiring 30 described with reference to FIG. 22 are both formed using through holes, but as can be seen from the above description, both are structurally functional. Is also different.

FIG. 11 is another example of a cross-sectional view when the current detection printed circuit board 1 is accommodated in a housing.
FIG. 11A is an example in which the through hole forming the shielding part 500 is not divided into two and is provided on the substrate except for the vicinity of the surface of the substrate, unlike FIG. This is a so-called blind via. Thus, although the structure of the shielding part 500 differs from FIG. 10, it is common in the part which provides the part which is not shielded in the part between the surface of a board | substrate, and a back surface. Even in this case, the electric field is shielded similarly to FIG. 10, and the magnetic flux acts on the coiled wiring 10.
Also, FIG. 11B differs from FIG. 10 in that the through hole forming the shielding portion 500 penetrates the substrate. Instead, the second housing shielding part 307 is not connected to the shielding part 500 and is a gap. In this case, a portion that is not shielded is not provided in a part between the front surface and the back surface of the substrate, but the same effect as in FIGS. 10 and 11A is obtained. That is, the electric field is shielded similarly to FIGS. 10 and 11A, and the magnetic flux is applied to the coiled wiring 10.

FIG. 12 is another example of a cross-sectional view when the current detection printed circuit board 1 is accommodated in a housing.
FIG. 12A shows an example using the casing main body 300 shown in FIG. 8 and the current detection printed circuit board 1 shown in FIG. That is, since the coil-shaped wiring 10 is formed between the inner layers, the housing body 300 shown in FIG. 8 can be used and the first housing shielding portion 306 can be dispensed with. In this case, since the through-hole forming the shielding part 500 is connected to the housing body 300, the same effect as in the case of FIGS.
FIG. 12B is an example in which the second housing shielding portion 307 is further removed to make the housing body 300 such that the through hole is connected to the lid 301. This case also has the same effect as in the case of FIGS.

As described above, when the shielding part 500 is provided on the current detection printed circuit board 1 as in the present embodiment, it is not necessary to form a shielding part having a complicated shape in the casing of the current detector. Therefore, the structure of the casing of the current detector can be simplified.
Moreover, since the shielding part of the current detection printed circuit board is formed by the through hole, it can be easily formed. Therefore, the structure of the current detector can be simplified.

(3) Modification of Current Detector 3 FIG. 13 shows a current detector 3 a that is a modification of the current detector 3. However, the lid 301a is not shown. FIG. 13 shows a case where the current detection printed circuit board 1 is the one shown in FIG. As shown in FIG. 13, the current conversion circuit 51 and the voltage conversion circuit 53 can be provided outside the current detector 3a. The casing uses a casing body 300a having a shape that matches the printed circuit board 1 for current detection. In addition, the output of the current detection printed circuit board 1 is output to the outside of the casing through output wiring that is not pattern wiring. In this case, the current conversion circuit 51 and the voltage conversion circuit 53 are separately provided outside the current detector 3a.

  FIG. 14 shows a current detector 3 b which is a modification of the current detector 3. However, the lid 301b is not shown. As shown in FIG. 14, a current conversion circuit 51 and a voltage conversion circuit 53 may be provided on the current detection printed circuit board 1. It should be noted that the output wiring of the current conversion circuit 51 and the output wiring of the voltage conversion circuit 53 may be partly patterned wiring, or all may be wiring other than pattern wiring.

  In the above description, the example in which the current detector 3 (including 3a to 3b) is provided at the input end 63a of the impedance matching device has been described. However, the present invention is not limited to this. For example, you may use for the output terminal of the high frequency power supply device 61, and you may provide in the output terminal 63b of an impedance matching apparatus. As described above, there is a difference in current and voltage between the input end 63a and the output end 63b (the same applies to the input end of the load 65) of the impedance matching device. Therefore, when the impedance matching device is provided at the output end 63b of the impedance matching device or the input end of the load 65, the power transmission conductor 68 is made thicker or the outer periphery of the power transmission conductor 68 in consideration of the difference. It is only necessary to increase the insulation distance by increasing the thickness of the insulator 69 covering the substrate. Moreover, you may use for uses other than a high frequency electric power supply system.

(4) Fixing Method By making the outer diameter of the insulator 69 substantially the same as the inner diameter of the through hole 303 provided in the housing body 300, the insulator 69 and the current detector 3 are substantially fixed. be able to. However, in practice, the outer diameter of the insulator 69 may be smaller than the inner diameter of the through hole. In this case, a gap is generated between the insulator 69 and the housing body 300. Thus, if there is a gap, when the electric power transmission conductor 66 and the current detector 3 and the current detector 3 are attached to the impedance matching device 63, the relative positions of the two may not be constant for each attached device. . That is, there is a possibility that the relative position between the power transmission conductor 66 and the like and the current detection printed circuit board 1 is not constant. Then, when a plurality of devices are manufactured, the detection value of each device may be a factor. Therefore, when the gap is large, it is desirable to make the relative position between the power transmission conductor 66 and the current detector 3 constant.

FIG. 15 is a diagram illustrating a method for fixing the insulator 69. As shown in FIG. 15, when a recess is provided in the insulator 69 and the lid 301 is fitted into the recess, the insulator 69 can be fixed by the lid 301. The lid 301 may be divided into two at the through hole portion. Thus, even when the outer diameter of the insulator 69 is smaller than the inner diameter of the through hole 303, the relative position between the power transmission conductor 66 and the current detection printed circuit board 1 is made substantially constant. can do.
In the case shown in FIG. 15, since the lid is only on the upper side of the housing, the insulator 69 may not be stably fixed. In this case, in order to make it more stable, an attachment part (not shown) for fixing the insulator 69 may be attached to the lower part of the housing body 300 (as viewed in the drawing).

  FIG. 16 is a diagram in the case where the power transmission conductor 66 and the insulator 69 are sized in accordance with the size of the current detector 3 in the current detector 3 shown in FIG.

  As shown in FIG. 15, when the insulator 69 is fixed to the current detector 3, in order to improve the maintainability, the power transmission conductor 66 and the insulator 69 are subjected to current detection as shown in FIG. The electric power transmission conductor 66 and the insulator 69 may be detachable together with the current detector 3 so as to have a size that matches the size of the device 3. By doing so, the maintainability can be improved. In addition, although illustration is abbreviate | omitted in FIG. 16, the connection part for connecting with the other conductor is provided in the conductor 66 for electric power transmission.

  In the description so far, the power transmission conductors 66 and 68 have been described as, for example, cylindrical copper bars, that is, those having a circular cross section. However, the present invention is not limited to this. For example, the cross section may be elliptical or rectangular. Further, although the through hole 401 of the current detection printed circuit board 1 has been described as being circular, the present invention is not limited to this. For example, it may be oval or rectangular.

  Further, as described above, since there are various types of shielding portions and coiled wirings 10 constituting the current detection printed circuit board 1, combinations other than those described may be used. For example, as shown in FIGS. 5 to 8 of Patent Document 1 (Japanese Patent Laid-Open No. 2007-225588), a plurality of types of coil-shaped wirings 10 may be provided on the current detection printed circuit board 1.

  Therefore, in the coil-shaped wiring 10 of the printed circuit board for current detection, a portion of the wiring penetrating between the uppermost layer and the lowermost layer of the substrate or a part of the substrate is a through hole, and the uppermost layer of the penetrating portion. The lowermost layer wiring may be a pattern wiring.

  Further, when a plurality of coil-shaped wirings 10 of the current detection printed circuit board are formed on the substrate, both ends of each coil-shaped wiring 10 or both ends of other coil-shaped wirings 10 are electrically at the same location. It may be possible to be electrically connected to a part or an electrically identical part.

  Further, as shown in FIG. 23, the current detector and the voltage detector may be used as a combined current / voltage detector.

FIG. 1 is a diagram showing an example of a printed circuit board 1 for current detection according to the present invention. FIG. 2 is a view showing another example of the printed circuit board 1 for current detection according to the present invention. FIG. 3 is a schematic external view showing the current detector 3 according to the present invention three-dimensionally. FIG. 4 is a schematic configuration diagram of the current detector 3 shown in FIG. FIG. 5 is a diagram of the housing body 300. FIG. 6 is a diagram illustrating the housing body 300 in a three-dimensional manner. FIG. 7 is a diagram when the current detection printed circuit board 1 is attached to the housing body 300 without the lid 301 attached. FIG. 8 is a diagram three-dimensionally illustrating the housing body 300 when the substrate fixing part 315 is not provided. FIG. 9 is an example of an application example of the third housing shielding unit 308. FIG. 10 is an example of a cross-sectional view when the current detection printed circuit board 1 is accommodated in a housing. FIG. 11 is another example of a cross-sectional view when the current detection printed circuit board 1 is accommodated in a housing. FIG. 12 is another example of a cross-sectional view when the current detection printed circuit board 1 is accommodated in a housing. FIG. 13 shows a current detector 3 a which is a modification of the current detector 3. FIG. 14 shows a current detector 3 b which is a modification of the current detector 3. FIG. 15 is a diagram illustrating a method for fixing the insulator 69. FIG. 16 is a diagram in the case where the power transmission conductor 66 and the insulator 69 are sized in accordance with the size of the current detector 3 in the current detector 3 shown in FIG. FIG. 17 is a block diagram of an example of a high-frequency power supply system in which the impedance matching device is used. FIG. 18 is a schematic circuit diagram of the current detector 80 and the voltage detector 90 provided between the input terminal of the impedance matching device 63 and the matching circuit 67. FIG. 19 is a circuit diagram when the current detector 80 and the voltage detector 90 are provided between the matching circuit in the impedance matching device and the output terminal. FIG. 20 is a diagram showing the current detection printed circuit board 6. FIG. 21 is a diagram illustrating another example of the printed circuit board 6 for current detection. FIG. 22 is a diagram showing the voltage detection printed circuit board 7. FIG. 23 is a schematic external view of the current / voltage detector 5. 24 is a schematic configuration diagram of the current / voltage detector 5 shown in FIG. FIG. 25 is a cross-sectional view of the current / voltage detector 5 shown in FIG. FIG. 26 is a diagram illustrating the housing body 330 in a three-dimensional manner. FIG. 27 is a diagram showing an example in which the current detection printed circuit board 6 and the voltage detection printed circuit board 7 are housed in separate housings, and are made into independent current detectors 3 and voltage detectors 4, respectively. . FIG. 28 is a cross-sectional view of the current detector 3 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Current detection printed circuit board 2 Voltage detection printed circuit board 3 Current detector 3a Current detector 3b Current detector 4 Voltage detector 5 Current / voltage detector 10 Coiled wiring 11 Through hole 12 Pattern wiring 13 Pattern wiring 30 Ring -Shaped wiring 66 Electric power transmission conductor 69 Insulator 300 covering the electric power transmission conductor 66 Current detector housing body 303 Through hole 306 First housing shielding portion 307 Second housing shielding portion 308 Third housing Shielding part 500 Shielding part 501 Through hole 502 Through hole

Claims (11)

A current detection printed circuit board for detecting an alternating current flowing in a power transmission conductor used as an AC power transmission path,
A through hole penetrating the substrate;
A shielding part disposed outside the through hole and formed by the through hole;
Wiring for performing current detection arranged outside the shielding part;
A printed circuit board for current detection.   The printed circuit board for current detection according to claim 1, wherein the shielding portion is formed by arranging a plurality of through holes in a substantially circular shape.   The printed circuit board for current detection according to claim 1, wherein the shielding portion is formed by arranging a plurality of through holes in a substantially circular shape and at least double. In a current detector for detecting an alternating current flowing in a power transmission conductor used as a transmission path for alternating current power,
A current detection print including a through hole penetrating the substrate, a shielding part disposed outside the through hole and formed by the through hole, and a wiring for performing current detection arranged outside the shielding part A substrate,
A housing made of a conductor configured to fix the current detection printed circuit board inside and provide a through hole for allowing the power transmission conductor to pass therethrough so as to cover the current detection printed circuit board; ,
With current detector.   The current detector according to claim 4, wherein the shielding portion of the current detection printed circuit board is formed by arranging a plurality of through holes in a substantially circular shape.   5. The current detector according to claim 4, wherein the shielding portion of the current detection printed circuit board is formed by arranging a plurality of through holes in a substantially circular shape and at least double. By the shielding part of the printed circuit board for current detection and the housing,
The current detector according to claim 4, wherein a shielding part including a part that is not partially shielded is formed between the through hole of the current detection printed circuit board and the wiring.   The current detector according to claim 7, wherein a portion of the shielding portion of the current detection printed board that is not shielded is provided between the front surface and the back surface of the substrate.   The current detector according to claim 7, wherein an unshielded portion of the shielding portion of the current detection printed circuit board is provided between the substrate and the housing.   The current detector according to any one of claims 4 to 9, wherein the casing includes a casing main body that fixes the current detection printed circuit board and a lid that covers the casing main body.   The current detector according to claim 4, wherein the AC power is AC power having a frequency in a radio frequency band.

Images