JP2017220636A - Noise shield plate and noise shield device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise shield plate having high noise shield effect, with simple configuration.SOLUTION: In a conductive noise shield plate 4 placed near a cable 3 conducting current while being insulated electrically, the length along the cable when it is projected to the plate surface of the noise shield plate, is different from integer times of 1/4 wavelength of a noise voltage conducting in the cable. Preferably, the length of the noise shield plate along the cable when it is projected to the plate surface of the noise shield plate, is less than 1/4 wavelength of the noise voltage conducting in the cable.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a noise shielding plate and a noise shielding device.

  2. Description of the Related Art Conventionally, a technique for preventing noise (electromagnetic waves) radiated from a cable or the like carrying a current from affecting other electronic devices is known. For example, Patent Document 1 describes a technique for shielding noise with an electromagnetic shield.

  In addition, a technique is known in which a ground wire is connected to an electromagnetic shield to enhance the effect of shielding noise. In a noise shielding device using an electromagnetic shield and a ground wire, the effect of shielding noise can be enhanced by increasing the thickness of the electromagnetic shield or increasing the number of ground wires.

JP 2014-90162 A

  However, when noise is shielded using a conventional noise shielding device, there is a problem that the electromagnetic shield becomes thick and the weight of the entire device increases, or the ground wire increases and the structure becomes complicated.

  The present invention has been made in view of the above, and an object thereof is to provide a noise shielding plate and a noise shielding device that have a simple configuration and have a high effect of shielding noise.

  In order to solve the above-described problems and achieve the object, the noise shielding plate according to one embodiment of the present invention is disposed in an electrically insulated state in the vicinity of a cable that conducts current, and has conductivity. A noise shielding plate having a length along the cable when the cable is projected onto a plate surface of the noise shielding plate is an integral multiple of a quarter wavelength of a noise voltage conducted in the cable. Characterized by different lengths.

  In the noise shielding plate according to one aspect of the present invention, the length along the cable when the cable is projected onto the plate surface of the noise shielding plate is ¼ of the noise voltage conducted in the cable. It is characterized by being less than the wavelength.

  In the noise shielding plate according to one aspect of the present invention, the maximum length between both ends of the noise shielding plate in the direction orthogonal to the cable is ¼ wavelength of the noise voltage conducted in the cable. The length is different from an integer multiple of.

  In the noise shielding plate according to one aspect of the present invention, the maximum length between both ends of the noise shielding plate in the direction orthogonal to the cable is ¼ wavelength of the noise voltage conducted in the cable. It is characterized by being less than.

  The noise shielding plate according to an aspect of the present invention is characterized in that the noise shielding plate is located in the vicinity of a position where the amplitude of a noise voltage conducted through the cable is large.

  Further, the noise shielding plate according to one aspect of the present invention is characterized in that a base material is positioned in the vicinity of a surface different from the surface on the cable side of the noise shielding plate.

  In the noise shielding plate according to an aspect of the present invention, the cable is located in the vicinity of the base material, and the noise shielding plate is located in the vicinity of a surface different from the surface on the base material side of the cable. It is characterized by.

  In the noise shielding plate according to one aspect of the present invention, the cable is located in the vicinity of the base material, and the noise shielding plate is located in a vicinity of a surface different from the surface on the cable side of the base material. It is characterized by.

  In the noise shielding plate according to one aspect of the present invention, the cable is located in the vicinity of the base material, and the noise shielding plate is located in the base material.

  The noise shielding plate according to one aspect of the present invention is characterized in that the noise shielding plate has a flat plate shape.

  The noise shielding plate according to one aspect of the present invention is characterized in that the noise shielding plate has a curved plate shape.

  In the noise shielding plate according to an aspect of the present invention, the cable is inserted through a cable bear, and the noise shielding plate is located on a surface of the cable bear along a direction in which the cable extends. It is characterized by.

  Moreover, the noise shielding apparatus which concerns on 1 aspect of this invention is equipped with said noise shielding board and the said cable which conducts an electric current, It is characterized by the above-mentioned.

  According to the present invention, it is possible to realize a noise shielding plate and a noise shielding device that have a simple configuration and are highly effective in shielding noise.

FIG. 1 is a schematic diagram showing a noise shielding plate and a cable serving as a noise radiation source according to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the first modification of the first embodiment. FIG. 3 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the second modification of the first embodiment. FIG. 4 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the third modification of the first embodiment. FIG. 5 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the fourth modification of the first embodiment. 6 is a cross-sectional view of the cable and the noise shielding plate of FIG. FIG. 7 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the fifth modification of the first embodiment. FIG. 8 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the sixth modification of the first embodiment. FIG. 9 is a diagram illustrating an arrangement example of the cable and the noise shielding plate in FIG. FIG. 10 is a diagram illustrating an arrangement example of the cable and the noise shielding plate in FIG. FIG. 11 is a diagram illustrating an arrangement example of the cable and the noise shielding plate in FIG. 8. FIG. 12 is a diagram illustrating an arrangement example of the cable and the noise shielding plate in FIG. FIG. 13 is a diagram illustrating an arrangement example of the cable and the noise shielding plate in FIG. FIG. 14 is a diagram illustrating an arrangement example of the cable and the noise shielding plate in FIG. FIG. 15 is a schematic diagram illustrating a configuration of a capsule endoscope guidance system including a noise shielding plate according to Embodiment 2 of the present invention.

  Embodiments of a noise shielding plate and a noise shielding device according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these embodiments. INDUSTRIAL APPLICABILITY The present invention can be generally applied to a noise shielding device including a cable that conducts current and a noise shielding plate that shields noise radiated from the cable.

  In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate. It should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a noise shielding plate and a cable serving as a noise radiation source according to Embodiment 1 of the present invention. As shown in FIG. 1, the first electronic component 1 and the second electronic component 2 to which electric power is supplied from the first electronic component 1 include the first electronic component 1 and the second electronic component 2. They are connected by a cable 3 that electrically connects them. A noise shielding plate 4 is disposed in the vicinity of the cable 3. A configuration including the cable 3 and the noise shielding plate 4 is a noise shielding device.

  The first electronic component 1 is a power generation source that supplies power to the second electronic component 2. The second electronic component 2 is an electronic component that operates with power supplied from the first electronic component 1. The first electronic component 1 and the second electronic component 2 are grounded by a ground wire.

  The cable 3 is an electric cable in which a conductive wire such as metal is covered with a coating made of an electrical insulator such as rubber. The cable 3 conducts current from the first electronic component 1 to the second electronic component 2. The cable 3 may be a shielded cable in which a conductive wire or mesh as an electromagnetic shield is disposed around the conductor via an electrical insulator.

  The noise shielding plate 4 has a flat plate shape and is made of a conductive material such as metal. The noise shielding plate 4 may be located in the vicinity of the cable 3, may be in contact with the cable 3, or may be separated from the cable 3. Further, the noise shielding plate 4 may have a curved plate shape, or may have a circular shape other than a quadrangle, and the shape is not particularly limited. Moreover, the noise shielding plate 4 is in an electrically insulated state. That is, the noise shielding plate 4 is not in contact with the ground wire or other conductive member. Specifically, the noise shielding plate 4 is located on a table made of an insulating material, for example, and the cable 3 is located on the noise shielding plate 4.

  As shown in FIG. 1, the length L1 of the noise shielding plate 4 along the cable 3 when the cable 3 is projected onto the surface of the noise shielding plate 4 is ¼ wavelength of the noise voltage conducted through the cable 3. Is less than.

  Here, noise (electromagnetic wave) emitted by the noise voltage is emitted around the cable 3. Since the noise emitted from the cable 3 passes through the noise shielding plate 4 located in the vicinity of the cable 3, the noise is suppressed from being emitted to the outside of the noise shielding device. In addition, since noise emitted from the cable 3 passes through the noise shielding plate 4 regardless of whether the noise shielding plate 4 is arranged on any of the upper, lower, left and right sides in the extending direction of the cable 3, noise is emitted to the outside of the noise shielding device. It can be suppressed.

  Further, when the length L1 is an integral multiple of 1/4 of the noise voltage wavelength in the transmission line, the noise voltage may be conducted to the noise shielding plate 4 and radiate noise. This is because the noise shielding plate 4 behaves as a quarter wavelength antenna. However, according to Embodiment 1, since the length L1 is less than ¼ wavelength of the noise voltage conducted through the cable 3, noise emission from the noise shielding plate 4 is suppressed. Therefore, the noise shielding plate 4 is a noise shielding plate having a simple configuration and a high effect of shielding noise.

  In addition, although Embodiment 1 mentioned above demonstrated the structure whose length L1 is less than 1/4 wavelength of the noise voltage conducted in the cable 3, it is not restricted to this. The length L1 may be a length different from an integral multiple of a quarter wavelength of the noise voltage conducted through the cable 3. Also in this case, the noise shielding plate 4 can be prevented from radiating noise as an antenna having an integral multiple of a quarter wavelength.

  In addition, the maximum length L2 between both ends of the noise shielding plate 4 in the direction orthogonal to the extending direction of the cable 3 is different from an integral multiple of a quarter wavelength of the noise voltage conducted in the cable 3. It is preferable that This is to prevent the noise shielding plate 4 from acting as a quarter wavelength antenna. Similarly, the length L2 is preferably less than a quarter wavelength of the noise voltage.

  Since the wavelength of the noise voltage in the transmission line is equal to the wavelength of the noise current, the lengths L1 and L2 are different from an integral multiple of a quarter wavelength of the noise current conducted through the cable 3. It may be.

(Modification 1)
FIG. 2 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the first modification of the first embodiment. As shown in FIG. 2, a plurality of noise shielding plates 14 may be in contact with each other in the direction along the cable 3. In this case, the length L11 and the length L12 of the noise shielding plate 14 that are in contact with each other along the cable 3 when the cable 3 is projected onto the plate surface of the noise shielding plate 14 are noises conducted in the cable 3. It may be less than a quarter wavelength of the voltage.

(Modification 2)
FIG. 3 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the second modification of the first embodiment. As shown in FIG. 3, when the cable 23 is bent and arranged, the noise shielding plate 24 is arranged so as to be orthogonal to the extending direction of the cable 23, and the cable 23 is projected onto the plate surface of the noise shielding plate 24. In this case, the length L21 of the noise shielding plate 24 along the cable 23 may be less than ¼ wavelength of the noise voltage conducted through the cable 23.

(Modification 3)
FIG. 4 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the third modification of the first embodiment. FIG. 4 shows the amplitude A of the noise voltage conducted through the cable 3. As shown in FIG. 4, a standing wave antinode may occur in the cable 3. In this case, noise can be efficiently shielded by disposing the noise shielding plate 34 at the antinode position of the standing wave having a large amplitude A. The position of the antinode of the standing wave can be obtained by calculation when the frequency of the noise to be shielded is known. Further, the position of the antinode of the standing wave may be obtained by measurement. Further, even if the anti-node of standing waves does not occur in the cable 3, there may be a position where the amplitude of the noise voltage conducted through the cable 3 is large and a small position. In that case as well, the noise shielding plate 34 may be positioned in the vicinity of the position where the amplitude is large.

  Even in this case, the length L31 of the noise shielding plate 34 along the cable 3 when the cable 3 is projected onto the plate surface of the noise shielding plate 34 is less than a quarter wavelength of the noise voltage conducted through the cable 3. I just need it.

  In addition, when the place where the noise shielding plate 34 can be disposed is limited due to restrictions in the design of the device, the antinode of the standing wave in the cable 3 is located at the position where the noise shielding plate 34 is disposed. The cable 3 may be routed.

(Modification 4)
FIG. 5 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the fourth modification of the first embodiment. As shown in FIG. 5, the noise shielding device of Modification 4 is arranged in the room R. The cable 43 is disposed along the wall surface of the room R. Also in this case, L41 of the length noise shielding plate 44 along the cable 43 when the cable 43 is projected onto the plate surface of the noise shielding plate 44 is less than a quarter wavelength of the noise voltage conducted in the cable 43. I just need it. In addition, when a cable and a noise shielding plate are arranged not in the room R but in the casing, the cable and the noise shielding plate can be similarly arranged on the wall surface of the casing.

  6 is a cross-sectional view of the cable and the noise shielding plate of FIG. As shown in FIG. 6, the cable 43 is located on the noise shielding plate 44, and the noise shielding plate 44 is located on the conductive wall surface 46 through an insulating member 45 made of rubber or the like. In addition, when the wall surface 46 does not have electroconductivity, the insulating member 45 is unnecessary.

(Modification 5)
FIG. 7 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the fifth modification of the first embodiment. As shown in FIG. 7, the cable 53 is inserted through a cable bear (registered trademark) 55. And the noise shielding board 54 is located in the surface along the direction where the cable 53 of the cable bear 55 extends | stretches. Also in this case, L51 of the length noise shielding plate 54 along the cable 53 when the cable 53 is projected onto the plate surface of the noise shielding plate 54 is less than a quarter wavelength of the noise voltage conducted through the cable 53. I just need it.

(Modification 6)
FIG. 8 is a schematic diagram illustrating a noise shielding plate and a cable serving as a noise radiation source according to the sixth modification of the first embodiment. As shown in FIG. 8, the first electronic component 61 and the second electronic component 62 are IC chips located on a base material B that is a substrate. The cable 63 and the noise shielding plate 64 are located on the base material B. A cable 63 indicates wiring on the substrate. Also in this case, the length L61 of the noise shielding plate 64 along the cable 63 when the cable 63 is projected onto the plate surface of the noise shielding plate 64 is less than a quarter wavelength of the noise voltage conducted through the cable 63. I just need it.

  Here, the example of arrangement | positioning of the base material B, the cable 63, and the noise shielding board 64 is demonstrated. 9-14 is a figure showing the example of arrangement | positioning of the cable of FIG. 8, and a noise shielding board. In any of the arrangement examples shown in FIGS. 9 to 14, the noise emitted from the cable 63 passes through the noise shielding plate 64 located in the vicinity of the cable 63, so that noise is generated outside the noise shielding device. Release is suppressed.

  As shown in FIG. 9, the noise shielding plate 64 is located on the base material B, and the cable 63 is located on the noise shielding plate 64. That is, the base material B is located in the vicinity of the surface of the noise shielding plate 64 opposite to the surface on the cable 63 side. Note that the noise shielding plate 64 is disposed so as not to contact the circuit printed on the base material B. Further, the cable 63 and the noise shielding plate 64 are insulated.

  As shown in FIG. 10, the noise shielding plate 64 is positioned on the base material B with the cable 63 interposed therebetween. That is, the noise shielding plate 64 is located in the vicinity of the surface of the cable 63 opposite to the surface on the base material B side. Further, the cable 63 and the noise shielding plate 64 are insulated.

  As shown in FIG. 11, the base material B is located between the noise shielding plate 64 and the cable 63. That is, the noise shielding plate 64 is located in the vicinity of the surface of the base material B opposite to the surface on the cable 63 side. In addition, since the noise shielding board 64 is arrange | positioned at the back surface side in which the circuit of the base material B is not printed, it is not contacting the circuit of the base material B.

  As shown in FIG. 12, the noise shielding plate 64 is located inside the base material B. The cable 63 is located on one side of the base material B.

  As shown in FIG. 13, the cable 63A is not covered with a coating made of an electrical insulator. In this case, a resist 65 having no conductivity is formed on the base material B, and the cable 63 </ b> A is located inside the resist 65. Further, the noise shielding plate 64 is located on the resist 65.

  As shown in FIG. 14, the cable 63A is not covered with a coating made of an electrical insulator. In this case, the cable 63A is covered with the insulating member 66, and the cable 63A and the insulating member 66 are located between the base material B and the noise shielding plate 64.

(Embodiment 2)
FIG. 15 is a schematic diagram illustrating a configuration of a capsule endoscope guidance system including a noise shielding plate according to Embodiment 2 of the present invention. As shown in FIG. 15, the capsule endoscope guidance system according to the second embodiment includes a control unit 101 as a first electronic component and a second electronic component to which power is supplied from the control unit 101. The drive part 102, the cable 103 which electrically connects between the control part 101 and the drive part 102, and the noise shielding board 104 located in the vicinity of the cable 103 are provided.

  The capsule endoscope guidance system includes a capsule endoscope 110, a bed 112 on which the subject 111 swallowed the capsule endoscope 110 is placed, and a capsule type attached to the abdomen of the subject 111. And an antenna unit 113 for receiving an image signal from the endoscope 110.

  The control unit 101 supplies power to the drive unit 102 and controls the drive of the drive unit 102. The drive unit 102 is driven by the electric power supplied from the control unit 101, and controls the position of the capsule endoscope 110 with a magnetic field. The control unit 101 and the drive unit 102 are grounded by a ground line.

  The capsule endoscope 110 captures an in-vivo image of the subject 111 and transmits the captured image as a radio signal having a frequency of 300 MHz or 400 MHz, for example. An antenna unit 113 attached to the abdomen of the subject 111 receives an image signal emitted from the capsule endoscope 110 and records image data on a recording medium.

  The cable 103 is an electric cable in which a conductive material such as metal is covered with a coating made of an electric insulator such as rubber. The cable 103 conducts current from the control unit 101 to the drive unit 102. The noise shielding plate 104 has a flat plate shape and is made of a conductive material such as metal.

  When noise voltage flows through the cable 103, noises (electromagnetic waves) having various frequencies are emitted from the cable 103. In particular, noise in the vicinity of frequencies of 300 MHz and 400 MHz is not preferable because image data received by the antenna unit 113 may be lost. Therefore, according to the second embodiment, as shown in FIG. 15, since the noise shielding plate 104 is positioned in the vicinity of the cable 103, noise emitted from the cable 103 passes through the noise shielding plate 104. It is prevented that the antenna unit 113 is irradiated with noise.

  Note that the noise shielding plate 104 has a length L121 along the cable 103 when the cable 103 of the noise shielding plate 104 is projected onto the plate surface of the noise shielding plate 104, and is ¼ of the noise voltage conducted through the cable 103. It is less than the wavelength.

  Here, a specific method for calculating the length L121 will be described. First, the wavelength λ of noise can be calculated as 100 cm by λ = c / ν, where c is the speed of light and ν is the frequency. Further, for example, when the current is conducted through the cable 103 having a relative dielectric constant ε = 3.0, the wavelength shortening rate α is 1 / √ε, and the 1/4 wavelength is about 14 cm by 100 cm × 1/4 × α. It can be calculated as 4 cm. Therefore, by making the length L121 smaller than 14.4 cm, the noise shielding plate 104 is prevented from acting as an antenna having a quarter wavelength, and noise having a frequency of 300 MHz that affects the image signal of the capsule endoscope 110 is prevented. Can be efficiently shielded. Thus, when the frequency of the noise to be shielded is known, the length L121 of the noise shielding plate 104 may be designed according to the frequency.

  Even in the second embodiment, the noise emitted from the cable 103 passes through the noise shielding plate 104 no matter which side of the noise shielding plate 104 is arranged on the upper, lower, left or right side in the extending direction of the cable 103. Irradiation to the antenna unit 113 can be prevented. Also in the second embodiment, the arrangements of the respective modifications of the first embodiment can be adopted. For example, as in the fourth modification of the first embodiment, the cable 103 and the noise shielding plate 104 are placed indoors or in a housing. You may arrange | position along the wall surface of a body.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1, 61 First electronic component 2, 62 Second electronic component 3, 23, 43, 53, 63, 63A, 103 Cable 4, 14, 24, 34, 44, 54, 64, 104 Noise shielding plate 45, 66 Insulating member 46 Wall surface 55 Cable bear 65 Resist 101 Control unit 102 Drive unit 110 Capsule endoscope 111 Subject 112 Bed 113 Antenna unit A Amplitude B Base material L1, L2, L11, L12, L21, L31, L41, L51 , L61, L121 length R room

Claims (13)

It is arranged in the state of being electrically insulated in the vicinity of the cable that conducts current, and is a noise shielding plate having conductivity,
The length along the cable when the cable is projected onto the plate surface of the noise shielding plate is different from an integral multiple of a quarter wavelength of the noise voltage conducted through the cable. Noise shielding plate.   The length along the cable when the cable is projected onto the plate surface of the noise shielding plate is less than a quarter wavelength of a noise voltage conducted through the cable. Noise shielding plate.   The maximum length between both ends of the noise shielding plate in the direction orthogonal to the cable is different from an integral multiple of a quarter wavelength of a noise voltage conducted through the cable. The noise shielding plate according to claim 1 or 2.   The maximum length between both ends of the noise shielding plate in a direction orthogonal to the cable is less than a quarter wavelength of a noise voltage conducted through the cable. The noise shielding board as described in any one.   The noise shielding plate according to any one of claims 1 to 4, wherein the noise shielding plate is positioned in the vicinity of a position where the amplitude of a noise voltage conducted through the cable is large.   The noise shielding plate according to any one of claims 1 to 5, wherein the base material is positioned in the vicinity of a surface different from the surface on the cable side of the noise shielding plate. The cable is located near the substrate;
The noise shielding plate according to any one of claims 1 to 5, wherein the noise shielding plate is positioned in the vicinity of a surface different from the surface of the cable on the base material side. The cable is located near the substrate;
The noise shielding plate according to any one of claims 1 to 5, wherein the noise shielding plate is located in the vicinity of a surface different from the surface on the cable side of the base material. The cable is located near the substrate;
The said noise shielding board is located in the said base material, The noise shielding board as described in any one of Claims 1-5 characterized by the above-mentioned.   The noise shielding plate according to claim 1, wherein the noise shielding plate has a flat plate shape.   The noise shielding plate according to claim 1, wherein the noise shielding plate has a curved plate shape. The cable is inserted through a cable bear,
The said noise shielding board is located in the surface along the direction where the said cable of the said cable bear extends | stretches, The noise shielding board as described in any one of Claims 1-5 characterized by the above-mentioned.   A noise shielding apparatus comprising: the noise shielding plate according to claim 1; and the cable that conducts current.

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