JP7589085B2 - Noise suppression sheet and coil device equipped with the same - Google Patents

Description

This disclosure relates to a noise suppression sheet and a coil device equipped with the same.

In recent years, wireless power transmission systems that transmit power wirelessly from a power transmission coil to a power receiving coil without using a power cable have been attracting attention (see Patent Document 1). A wireless power transmission system includes a wireless power transmission device having a power transmission coil and a wireless power receiving device having a power receiving coil, and wireless power transmission is achieved by linking the magnetic flux generated from the power transmission coil with the power receiving coil.

Special Publication No. 2020-524438

However, some of the magnetic flux generated by the transmitting coil does not interlink with the receiving coil and is instead radiated to the surroundings as radiation noise. Such radiation noise can cause nearby electronic devices to malfunction, so it is desirable to suppress it as much as possible.

Therefore, the present disclosure aims to provide a noise suppression sheet capable of suppressing the emission of unnecessary radiation noise and a coil device equipped with the same.

A noise suppression sheet according to one embodiment of the present disclosure comprises an insulating substrate and a conductor pattern provided on a surface of the insulating substrate, the conductor pattern including first and second linear patterns extending in a first direction, the first linear pattern being electrically connected to ground via a first portion and connected to the second linear pattern at a second portion that is at a different position in the first direction from the first portion, and the first and second linear patterns have cross-sectional shapes in which the pattern width increases the closer they are to the insulating substrate.

In this way, according to the present disclosure, it is possible to provide a noise suppression sheet capable of suppressing the emission of unnecessary radiation noise, and a coil device equipped with the same.

FIG. 1 is a schematic plan view for illustrating the structure of a noise suppression sheet 1A according to a first embodiment of the present disclosure. FIG. 2 is an enlarged view of area A shown in FIG. FIG. 3 is a schematic cross-sectional view taken along line BB shown in FIG. FIG. 4 is a block diagram showing the configuration of a wireless power transmission system 100 using the noise suppression sheet 1A. FIG. 5 is a schematic cross-sectional view illustrating the positional relationship between the noise suppression sheet 1A and the power transmission coil 2. As shown in FIG. FIG. 6 is a schematic plan view illustrating the structure of a noise suppression sheet 1Aa according to a first modified example. FIG. 7 is a schematic perspective view illustrating the structure of a noise suppression sheet 1Ab according to a second modified example. FIG. 8 is a schematic plan view illustrating the structure of a noise suppression sheet 1B according to a second embodiment of the present disclosure. FIG. 9 is an enlarged view of area A shown in FIG.

A preferred embodiment of the present disclosure will now be described in detail with reference to the accompanying drawings.

First Embodiment
Fig. 1 is a schematic plan view illustrating the structure of a noise suppression sheet 1A according to a first embodiment of the present disclosure, Fig. 2 is an enlarged view of an area A shown in Fig. 1, and Fig. 3 is a schematic cross-sectional view taken along line B-B shown in Fig. 2.

As shown in Figures 1 to 3, the noise suppression sheet 1A according to the first embodiment is composed of an insulating substrate 10 and a conductor pattern 20 provided on the surface 11 of the insulating substrate 10. The material of the insulating substrate 10 is not particularly limited, but it is preferable to use a flexible material such as a PET film rather than a rigid material used in PCBs. It is preferable that the thickness T of the insulating substrate 10 is as thin as possible while ensuring mechanical strength. As an example, when a PET film is used as the material of the insulating substrate 10, the thickness T can be about 20 μm. No conductor pattern 20 is provided on the back surface 12 of the insulating substrate 10.

The conductor patterns 20 are made of a good conductor such as copper (Cu), and include first to fourth groups 21 to 24 each including a plurality of linear patterns extending in the y direction, a connecting pattern 25 extending in the x direction, a terminal connection portion 26, and a plurality of connection patterns 27 connecting the connecting pattern 25 and the terminal connection portion 26. A ground potential is applied to these conductor patterns 20 via the terminal connection portion 26.

The first to fourth groups 21 to 24 are arranged in the x direction, and each has a structure in which multiple linear patterns extending in the y direction are connected in a meandering pattern. The y direction is an example of the first direction, and the x direction is an example of the second direction.

The first group 21 has n linear patterns 21 ₁ to 21 _n , and one end in the y direction of the first linear pattern 21 ₁ (end in the -y direction, first portion) is connected to the connecting pattern 25, the other end in the y direction of the first linear pattern 21 ₁ (end in the +y direction, second portion) is connected to one end in the y direction of the second linear pattern 21 ₂ (end in the +y direction), and the other end in the y direction of the second linear pattern 21 ₂ (end in the -y direction, third portion) is connected to one end in the y direction of the third linear pattern 21 ₃ (end in the -y direction). In this way, the end in the +y direction of the i-th (i is an odd number) linear pattern 21 _i is connected to the end in the +y direction of the i+1-th linear pattern 21 _i+1 , and the end in the -y direction of the i+1-th linear pattern 21 _i+1 is connected to the end in the -y direction of the i+2-th linear pattern 21 _i+2 . This results in n linear patterns 21 ₁ to 21 _n being connected in a meandering pattern. The end of the n-th linear pattern 21 _n is open. That is, the first group 21 forms a meandering pattern in which one end is connected to the connection pattern 25 and the other end is open. The first group 21 is also electrically connected to ground via one end in the y direction of the first linear pattern 21 ₁ (the end in the -y direction, the first portion).

Among the n linear patterns 21 ₁ to 21 _n , the linear pattern 21 ₁ arranged at the end in the x direction is connected via a connection pattern 28 having a curved round shape. The linear patterns 21 ₁ to 21 _n adjacent to each other in the x direction are also connected via a connection pattern 29 having a round shape. The connection pattern 28 has a shape in which the extension direction gradually changes from the x direction to the y direction from the linking pattern 25 toward the linear pattern 21 _1. The connection pattern 29 extends in the x direction, and both ends of the connection pattern 29 have a shape in which the extension direction gradually changes from the x direction to the y direction. In this way, since the connection patterns 28 and 29 do not have corners, the bias of the current flowing through the connection patterns 28 and 29 is reduced, and as a result, the loss due to the noise suppression sheet 1A is reduced. The radius of curvature of the connection pattern 28 having a round shape is relatively large, and as a result, the length in the y direction of some linear patterns including the first linear pattern 21 ₁ is shortened. In this embodiment, the length in the y direction of the linear patterns 21 ₁ to 21 ₄ is shorter than the length in the y direction of the other linear patterns 21 ₅ to 21 _n .

The second group 22 has a pattern shape similar to that of the first group 21. That is, n-1 linear patterns 22 ₁ to 22 _n-1 are connected in a meandering shape, one end of the first linear pattern 22 ₁ is connected to the connecting pattern 25, and one end of the n-1-th linear pattern 22 _n-1 is open. Group 21 is disposed at one end in the x direction, and group 22 is disposed at the other end in the x direction.

The third and fourth groups 23, 24 are arranged so as to be sandwiched between the groups 21, 22 in the x direction, and have a configuration in which m linear patterns 23 ₁ to 23 _m and 24 ₁ to 24 _m are connected in a meandering shape. One end of the first linear patterns 23 ₁ and 24 ₁ is connected to the connecting pattern 25, and one end of the mth linear patterns 23 _m and 24 _m is open. In this embodiment, n>m, and therefore both groups 23 and 24 have the same pattern shape as a part of the groups 21 and 22. In this embodiment, the lengths in the y direction of the linear patterns 23 ₁ to 23 _m and 24 ₁ to 24 _m are equal to each other.

In this way, each of groups 21 to 24 has a configuration in which a plurality of linear patterns are connected in a meandering pattern, one end of which is connected to connecting pattern 25 and the other end is open. For this reason, when a magnetic field in the z direction is applied to noise suppression sheet 1A, a portion of the magnetic field is applied to linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m that constitute groups 21 to 24, generating eddy currents, but because groups 21 to 24 do not constitute loop-shaped patterns, no loss occurs due to the current generated by the magnetic field looping widely.

Here, the pattern width of the connecting pattern 25 in the y direction is W1, and the pattern width of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m in the x direction is W2. The interval between the connecting pattern 25 and the connection pattern 29 in the x direction is S1, and the interval in the x direction between the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m adjacent in the x direction is S2. Furthermore, the conductor thickness of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m is H. The conductor thickness H is about 1 to 35 μm, and may be gradually thinner from the linear patterns 21 ₁ , 22 ₁ , 23 ₁ , and 24 ₁ connected to the connecting pattern 25 toward the linear patterns 21 _n , 22 _n , 23 _m , and 24 _m whose ends are open. As an example, the conductor thickness of the linear pattern 21 ₂ may be thinner than that of the linear pattern 21 ₁ and thicker than that of the linear pattern 21 _3. In this way, by making the conductor thickness H thicker closer to the linear patterns 21 ₁ , 22 ₁ , 23 ₁ , and 24 ₁ connected to the connecting pattern 25 and thinner closer to the linear patterns 21 _n , 22 _n , 23 _m , and 24 _m whose ends are open, the difference in the current value per unit cross-sectional area is mitigated, and as a result, the loss due to the noise suppression sheet 1A is reduced.

As described above, the thickness T of the insulating base material 10 is sufficiently thin, and is preferably thinner than the conductor thickness H of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m . Furthermore, the pattern width W2 of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m may be greater than the conductor thickness H. This makes it easier to fabricate the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m , since the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m are not too thin and are not too thick.

The pattern width W2 of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m is the width of the portion in contact with the insulating substrate 10, and the pattern width W3 of the upper surface is smaller than the pattern width W2 of the portion in contact with the insulating substrate 10. In other words, the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m have a cross-sectional shape in which the pattern width becomes wider the closer to the insulating substrate 10. Such a cross-sectional shape makes it possible to suppress eddy currents while ensuring sufficient adhesion strength to the insulating substrate 10.

In this embodiment, the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m are designed to have a larger spacing S2 than the pattern width W2. In other words, S2>W2. This is because by ensuring a sufficient spacing S2, magnetic flux can easily pass between the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m . As an example, the pattern width W2 can be about 0.1 to 0.2 mm, and the spacing S2 can be about 0.1 to 1 mm.

The pattern width W1 of the connection pattern 25 is, for example, about 0.1 to 5 mm, and is preferably larger than the pattern width W2 of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m . This is because the electric potential of the linear patterns becomes more stable by increasing the pattern width W1 of the connection pattern 25 connected to a large number of linear patterns. However, if the pattern width W1 of the connection pattern 25 is too wide, it becomes difficult for the magnetic flux to pass through, so the pattern width W1 of the connection pattern 25 is preferably smaller than the interval S2. As an example, if the pattern width W2 of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m is 0.1 mm and the interval S2 is 0.9 mm, the pattern width W1 of the connection pattern 25 can be about 0.2 mm. The spacing S1 between the coupling pattern 25 and the connection pattern 29 in the x direction can be set to about 0.3 to 0.5 mm.

As shown in FIG. 1, the terminal connection portion 26 is connected to the linking pattern 25 via a plurality of connection patterns 27. The connection position of the terminal connection portion 26 is near the end of the linking pattern 25, and is arranged offset in the x direction. This makes it possible to reduce interference between the terminal connection portion 26 and the magnetic flux. In addition, since the terminal connection portion 26 is not directly connected to the linking pattern 25, but is connected via a plurality of connection patterns 27 extending in the y direction and arranged in the x direction, it becomes easier for the magnetic flux to pass near the terminal connection portion 26.

Figure 4 is a block diagram showing the configuration of a wireless power transmission system 100 using the noise suppression sheet 1A.

The wireless power transmission system 100 shown in FIG. 4 includes a power transmission coil 2, a power receiving coil 3, a power transmission circuit 4 that passes an AC current through the power transmission coil 2, and a power receiving circuit 5 that receives the AC current flowing through the power receiving coil 3. A noise suppression sheet 1A is disposed between the power transmission coil 2 and the power receiving coil 3. The power transmission circuit 4 is supplied with DC power via a power supply circuit 6. The DC power output from the power receiving circuit 5 is supplied to a load circuit 7. This constitutes a wireless power transmission system, with the power transmission coil 2 and the power transmission circuit 4 constituting a wireless power transmitting device, and the power receiving coil 3 and the power receiving circuit 5 constituting a wireless power receiving device.

When an AC current flows through the power transmission coil 2, a magnetic flux φ is generated from the power transmission coil 2. Most of this magnetic flux φ is interlinked with the power receiving coil 3, causing an AC current to flow through the power receiving coil 3. However, a portion of the magnetic flux φ generated from the power transmission coil 2 is not interlinked with the power receiving coil 3 and is radiated to the surroundings as radiation noise. Such radiation noise may cause surrounding electronic devices to malfunction, so it is desirable to suppress it as much as possible. The noise suppression sheet 1A according to this embodiment reduces such radiation noise, and by being disposed between the power transmission coil 2 and the power receiving coil 3 and in the vicinity of the power transmission coil 2, it is possible to shield most of the radiation noise while ensuring the magnetic flux φ interlinked with the power receiving coil 3. In this way, the noise suppression sheet 1A according to this embodiment can be used in a wireless power transmission system.

Figure 5 is a schematic cross-sectional view illustrating the positional relationship between the noise suppression sheet 1A and the power transmission coil 2.

As shown in FIG. 5, the power transmission coil 2 includes an insulating substrate 30 made of a PET film or the like, and coil patterns 41 and 42 formed on the front surface 31 and rear surface 32 of the insulating substrate 30, respectively. The coil patterns 41 and 42 are connected in series or parallel to form a coil conductor. The surface of the coil pattern 41 formed on the front surface 31 of the insulating substrate 30 forms the coil radiation surface 2a of the power transmission coil 2. The surface of the coil pattern 42 formed on the rear surface 32 of the insulating substrate 30 forms the coil rear surface 2b of the power transmission coil 2. A noise suppression sheet 1A is disposed to face the coil radiation surface 2a, and a magnetic sheet 8 is disposed to face the coil rear surface 2b. There is no structural difference between the coil radiation surface 2a and the coil rear surface 2b, but the side facing the noise suppression sheet 1A is defined as the coil radiation surface 2a, and the side facing the magnetic sheet 8 is defined as the coil rear surface 2b. The power transmission coil 2, the noise suppression sheet 1A, and the magnetic sheet 8 form a coil device.

The back surface 12 of the insulating substrate 10 constituting the noise suppression sheet 1A is laminated on the coil radiation surface 2a of the power transmission coil 2 via an insulating resist 51. The resist 51 is an insulating member provided to prevent conductive foreign matter from adhering to the surface of the coil pattern 41. As a result, the resist 51 and the insulating substrate 10 are interposed between the coil pattern 41 and the conductor pattern 20. The distance from the coil radiation surface 2a to the surface of the conductor pattern 20, that is, the total thickness of the resist 51 and the insulating substrate 10, is L1.

The coil back surface 2b of the power transmission coil 2 is adhered to the magnetic sheet 8 via an insulating adhesive sheet 52. The distance from the coil radiation surface 2a to the surface of the magnetic sheet 8, that is, the total thickness of the coil patterns 41, 42, the insulating base material 30, and the adhesive sheet 52, is L2. Here, the distance L1 from the coil radiation surface 2a to the surface of the conductor pattern 20 is preferably equal to or less than the distance L2 from the coil radiation surface 2a to the surface of the magnetic sheet 8, and more preferably equal to or less than half the distance L2. This is because unnecessary radiation noise can be more effectively shielded _by shortening the distance L1 as much as possible. In particular, the distance _L1 is preferably smaller than the skin depth of the electromagnetic field generated by the current flowing through the coil patterns 41, 42 and incident on the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _{n , 23 1 to 23 m} , and 24 ₁ to 24 _m . This makes it possible to more effectively shield unnecessary radiation noise while sufficiently securing the Q value of the power transmission coil 2.

In addition, in order to more effectively shield unwanted radiation noise, it is preferable that the outer size D1 of the conductor pattern 20 provided on the noise suppression sheet 1A is larger than the outer size D2 of the power transmission coil 2, and it is preferable that the entire power transmission coil 2 is covered by the formation area of the conductor pattern 20 in a planar view. In this way, by covering the entire power transmission coil 2 with the formation area of the conductor pattern 20, it is possible to more effectively shield unwanted radiation noise.

Furthermore, the pattern width W2 and conductor thickness H of the linear patterns 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 1 to 24 _m are preferably smaller than the skin depth of the _{electromagnetic field generated by the current flowing through the coil patterns 41 and 42 and incident on the linear patterns 21 1 to} 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , and 24 ₁ to 24 _m . This reduces the attenuation of the carrier wave radiated from the coil patterns 41 and 42. As an example, when the frequency of the carrier wave flowing through the coil patterns 41 and 42 is 0.1 MHz to 0.2 MHz, the skin depth is 147 μm to 207 μm, so by setting the pattern width W2 and conductor thickness H to less than this, it is possible to suppress the attenuation of the carrier wave.

In addition to or instead of placing the noise suppression sheet 1A near the power transmission coil 2, the noise suppression sheet 1A may be placed near the power receiving coil 3. In this case, the power receiving coil 3, the noise suppression sheet 1A, and the magnetic sheet 8 constitute a coil device.

As described above, by disposing the noise suppression sheet 1A according to this embodiment between the power transmission coil 2 and the power receiving coil 3, it is possible to reduce unnecessary radiation noise emitted to the surroundings while ensuring a sufficient Q value of the power transmission coil 2. Moreover, in the noise suppression sheet 1A according to this embodiment, the multiple linear patterns constituting the groups 21 to 24 are connected in a meandering shape, so that the phenomenon of noise increasing at specific frequencies is suppressed, and it is possible to obtain a noise suppression effect in a wide range of frequency ranges of the noise regulation standards. Furthermore, since the connection pattern 28 has a round shape, the variation in the circumferential direction of the distance from the edges of the coil patterns 41 and 42 to the edges of the noise suppression sheet 1A in a plan view is suppressed, and as a result, the variation in the noise current flowing through the conductor pattern 20 is suppressed, and the noise reduction effect is improved.

Fig. 6 is a schematic plan view for explaining the structure of a noise suppression sheet 1Aa according to a first modification of this embodiment. The noise suppression sheet 1Aa according to the first modification differs from the noise suppression sheet 1A shown in Fig. 1 in that the linear patterns constituting group 22 are symmetrical to the linear patterns constituting group 21. In other words, the linear patterns 21 ₁ to 21 _n constituting group 21 and the linear patterns 22 ₁ to 22 _n constituting group 21 have shapes that are line-symmetrical to each other with respect to a virtual line S extending in the y direction as the axis of symmetry. Making groups 21 and 22 symmetrical in this way makes it easier to design the linear patterns.

7 is a schematic perspective view for explaining the structure of a noise suppression sheet 1Ab according to a second modified example of this embodiment. The noise suppression sheet 1Ab according to the second modified example has linear patterns 70 ₁ to 70 _k connected in a meandering shape on the surface 11 of the insulating substrate 10, one end of which is directly connected to the terminal connection portion 26 and the other end is open. In this manner, it is not essential to divide the linear patterns into a plurality of groups, and it is also not essential to use a connecting pattern.

Second Embodiment
Fig. 6 is a schematic plan view for illustrating the structure of a noise suppression sheet 1B according to a second embodiment of the present disclosure, and Fig. 7 is an enlarged view of a region A shown in Fig. 6.

As shown in Figures 6 and 7, the noise suppression sheet 1B according to the second embodiment differs from the noise suppression sheet 1A according to the first embodiment in that groups 21 to 24 of the conductor pattern 20 are replaced with groups 61 to 63. Since the other basic configuration is the same as that of the noise suppression sheet 1A according to the first embodiment, the same elements are given the same reference numerals and redundant explanations are omitted.

The groups 61 to 63 are arranged in the x direction. The first group 61 has four linear patterns 61 ₁ to 61 ₄ , and one end in the y direction of the first linear pattern 61 ₁ (the end in the −y direction, the first portion) is connected to the connecting pattern 25, a substantially central portion in the y direction of the first linear pattern 61 ₁ (the second portion) is connected to a substantially central portion in the y direction of the second linear pattern 61 ₂ , one end in the y direction of the third linear pattern 61 ₃ (the end in the −y direction, the third portion) is connected to the connecting pattern 25, and a substantially central portion in the y direction of the third linear pattern 61 ₃ (the fourth portion whose position in the y direction is equal to that of the second portion) is connected to a substantially central portion in the y direction of the fourth linear pattern 61 ₄ . In this way, one end in the y direction of the odd-numbered linear patterns ₆₁₁ and ₆₁₃ is connected to the connecting pattern 25, and the approximate center in the y direction of the even-numbered linear patterns ₆₁₂ and ₆₁₄ is connected to the approximate center in the y direction of the linear patterns ₆₁₁ and _613. The other ends in the y direction (ends in the +y direction) of the linear patterns ₆₁₁ and ₆₁₃ are open. Both ends in the y direction of the linear patterns ₆₁₂ and ₆₁₄ are also open.

The second group 62 has four linear patterns 62 ₁ to 62 ₄ , one end in the y direction of the linear patterns 62 ₁ and 62 ₃ is connected to the connecting pattern 25, the approximate center in the y direction of the linear pattern 62 ₂ is connected to the approximate center in the y direction of the linear pattern 62 ₃ , and the approximate center in the y direction of the linear pattern 62 ₄ is connected to the approximate center in the y direction of the linear pattern 63 _p belonging to the third group. In this way, one end in the y direction of the odd-numbered linear patterns 62 ₁ and 62 ₃ is connected to the connecting pattern 25, and the approximate center in the y direction of the even-numbered linear patterns 62 ₂ and 62 ₄ are connected to the approximate center in the y direction of the odd-numbered linear patterns 62 ₃ and 63 _p . The other ends in the y direction (ends in the +y direction) of the linear patterns 62 ₁ and 62 ₃ are open. Both ends of the linear patterns 62 ₂ and 62 ₄ in the y direction are also open.

The third group 63 is arranged so as to be sandwiched between the groups 61 and 62 in the x direction, and has p linear patterns 63 ₁ to 63 _p . Similarly to the groups 61 and 62, one end in the y direction of the odd-numbered linear patterns 63 ₁ , 63 ₃ ... is connected to the connecting pattern 25, and the approximate center in the y direction of the even-numbered linear patterns 63 ₂ , 63 ₄ ... is connected to the approximate center in the y direction of the linear patterns 63 ₁ , 63 ₃ .... The other ends in the y direction (ends in the +y direction) of the linear patterns 63 ₁ , 63 ₃ ... are open. Both ends in the y direction of the linear patterns 63 ₂ , 63 ₄ ... are also open.

In this way, groups 61 to 63 have a structure with multiple units in which two linear patterns are connected in the shape of the letter "H." Even with this structure, groups 61 to 63 do not form a loop-shaped pattern, so there is no loss caused by the current generated by the magnetic field looping widely.

Here, the linear patterns _61.sub.1 , _62.sub.1 arranged at the ends in the x direction are connected via the connection pattern 28 having a rounded shape. This reduces bias in the current flowing through the connection pattern 28, thereby reducing loss due to the noise suppression sheet 1B. The radius of curvature of the connection pattern 28 having a rounded shape is relatively large, and as a result, the linear patterns _61.sub.1 to _61.sub.4 , _62.sub.1 to _62.sub.4 constituting the groups 61, 62 are shorter in length in the y direction than the linear patterns _63.sub.1 to _63.sub.p constituting the group 63.

As with the noise suppression sheet 1A according to the first embodiment, the noise suppression sheet 1B according to this embodiment can be disposed between the power transmission coil 2 and the power receiving coil 3 to more effectively block unwanted radiation noise. Furthermore, since the noise suppression sheet 1B according to this embodiment has a plurality of linear patterns with the above-described structure, it is possible to obtain a balanced noise suppression effect in the frequency range of the noise regulation standard in addition to the effect of the noise suppression sheet 1A according to the first embodiment.

Although the above describes preferred embodiments of the present disclosure, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present disclosure, and it goes without saying that these modifications are also included within the scope of the present disclosure.

The technology disclosed herein includes, but is not limited to, the following configuration examples:

A noise suppression sheet according to one embodiment of the present disclosure comprises an insulating substrate and a conductor pattern provided on a surface of the insulating substrate, the conductor pattern including first and second linear patterns extending in a first direction, the first linear pattern being electrically connected to ground via a first portion and connected to the second linear pattern at a second portion that is at a different position in the first direction from the first portion, and the first and second linear patterns have cross-sectional shapes in which the pattern width increases the closer they are to the insulating substrate.

A noise suppression sheet having such a configuration can be placed on the surface of a coil pattern that generates a magnetic field to reduce unnecessary radiation noise emitted into the surrounding area.

The conductor pattern may further include a third linear pattern extending in the first direction, and the second linear pattern may be connected to the third linear pattern at a third portion that is at a different position in the first direction from the second portion. In this way, the first to third linear patterns are connected in a meandering manner, thereby suppressing the phenomenon of increased noise at certain frequencies.

The conductor thickness of the first linear pattern may be thicker than that of the third linear pattern, and the conductor thickness of the second linear pattern may be thinner than that of the first linear pattern and thicker than that of the third linear pattern. This reduces the difference in current value per unit cross-sectional area.

The second linear pattern is connected to the first linear pattern at one end in the first direction and to the third linear pattern at the other end in the first direction, and the connection pattern connecting the second linear pattern to the first and third linear patterns may have a round shape. This reduces bias in the current flowing through the connection pattern, and as a result, the loss due to the noise suppression sheet is reduced.

The conductor pattern may include a first group including first and second linear patterns, and a second group arranged in a second direction perpendicular to the first direction with respect to the first group, and having a shape that is linearly symmetrical to the first group with a line parallel to the first direction as an axis of symmetry. This allows magnetic fields generated by noise currents flowing through the conductor pattern to be cancelled out by each other, enhancing the noise suppression effect. The conductor pattern may further include third and fourth groups arranged to be sandwiched between the first and second groups from the second direction, and having the same pattern shape as part of the first group. This makes it easier to design the conductor pattern. Also, the line length of the conductor pattern near the center, where the magnetic field generated by the coil pattern is large, is shortened, reducing loss due to noise currents flowing through the conductor pattern.

The conductor pattern may further include third and fourth linear patterns extending in the first direction, and the third linear pattern may be electrically connected to ground via a third portion and connected to the fourth linear pattern at a fourth portion that is at a different position in the first direction from the third portion. This makes it possible to obtain a balanced noise suppression effect in the frequency range of the noise regulation standard. In this case, the second and fourth portions may be located approximately in the center of the first and third linear patterns in the first direction. This enhances the noise suppression effect.

The noise suppression sheet further includes a connecting pattern that extends in a second direction perpendicular to the first direction and is electrically connected to ground, the first linear pattern is connected to the connecting pattern at a first portion and is disposed at an end in the second direction, and the connection pattern that connects the connecting pattern and the first linear pattern may have a round shape. This reduces bias in the current flowing through the connection pattern, and as a result, the loss caused by the noise suppression sheet is reduced.

The thickness of the first and second linear patterns may be greater than the thickness of the insulating substrate. This allows the linear patterns to be closer to the coil pattern.

The coil device according to one embodiment of the present disclosure is characterized in that it comprises the above-mentioned magnetic suppression sheet, a magnetic sheet, and a coil pattern disposed between the magnetic suppression sheet and the magnetic sheet and having a coil surface facing the magnetic suppression sheet.

Such a coil device makes it possible to reduce unnecessary radiation noise emitted from the coil pattern to the surrounding area.

The pattern width of the first and second linear patterns is generated by the current flowing through the coil pattern, and may be smaller than the skin depth of the electromagnetic field incident on the first and second linear patterns. Also, the conductor thickness of the first and second linear patterns is generated by the current flowing through the coil pattern, and may be smaller than the skin depth of the electromagnetic field incident on the first and second linear patterns. This reduces the attenuation of the carrier wave radiated from the coil pattern.

The distance between the coil pattern and the conductor pattern may be smaller than the skin depth of the electromagnetic field that is generated by the current flowing through the coil pattern and that is incident on the first and second linear patterns. This makes it possible to more effectively shield unwanted radiation noise while still ensuring a sufficient Q value for the coil pattern.

DESCRIPTION OF THE REFERENCE NUMERALS 1A, 1Aa, 1Ab, 1B Noise suppression sheet 2 Power transmitting coil 2a Coil radiation surface 2b Coil rear surface 3 Power receiving coil 4 Power transmitting circuit 5 Power receiving circuit 6 Power supply circuit 7 Load circuit 8 Magnetic sheet 10 Insulating substrate 11 Front surface 12 of insulating substrate Back surface 20 of insulating substrate Conductor patterns 21 to 24 Groups 21 ₁ to 21 _n , 22 ₁ to 22 _n , 23 ₁ to 23 _m , 24 ₁ to 24 _m Linear pattern 25 Linking pattern 26 Terminal connection portions 27 to 29 Connection pattern 30 Insulating substrate 31 Front surface 32 of insulating substrate Back surface 41, 42 of insulating substrate Coil pattern 51 Resist 52 Adhesive sheets 61 to 63 Groups 61 ₁ to 61 ₄ , 62 ₁ to 62 ₄ , 63 ₁ to 63 _p , 70 ₁ to 70 _k Linear pattern 100 Wireless power transmission system φ Magnetic flux

Claims (12)

An insulating substrate;
A conductor pattern provided on a surface of the insulating substrate,
the conductor pattern includes first , second and third linear patterns extending in a first direction;
the first linear pattern is electrically connected to ground via a first portion, and is connected to the second linear pattern at a second portion that is positioned differently from the first portion in the first direction;
the second linear pattern is connected to the third linear pattern at a third portion that is located at a position different from that of the second portion in the first direction;
a conductor thickness of the first linear pattern is greater than a conductor thickness of the third linear pattern;
A noise suppression sheet, wherein the first and second linear patterns have cross-sectional shapes in which the pattern width increases toward the insulating substrate. 2 . The noise suppression sheet according to claim 1 , wherein a conductor thickness of the second linear pattern is thinner than a conductor thickness of the first linear pattern and thicker than a conductor thickness of the third linear pattern. the second linear pattern is connected to the first linear pattern at one end in the first direction and connected to the third linear pattern at the other end in the first direction;
3. The noise suppression sheet according to claim 1 , wherein a connection pattern that connects the second linear pattern to the first and third linear patterns has a rounded shape. An insulating substrate;
A conductor pattern provided on a surface of the insulating substrate,
the conductor pattern includes first and second linear patterns extending in a first direction;
the first linear pattern is electrically connected to ground via a first portion, and is connected to the second linear pattern at a second portion that is positioned differently from the first portion in the first direction;
the first and second linear patterns have a cross-sectional shape in which the pattern width becomes wider toward the insulating base material,
the conductor pattern includes a first group including the first and second linear patterns, and a second group arranged in a second direction perpendicular to the first direction with respect to the first group, and having a shape that is linearly symmetrical to the first group with respect to a line parallel to the first direction as an axis of symmetry. 5. The noise suppression sheet according to claim 4, wherein the conductor pattern further includes third and fourth groups arranged to be sandwiched between the first and second groups in the second direction and having the same pattern shape as a portion of the first group. An insulating substrate;
A conductor pattern provided on a surface of the insulating substrate,
the conductor pattern includes first, second, third and fourth linear patterns extending in a first direction;
the first linear pattern is electrically connected to ground via a first portion, and is connected to the second linear pattern at a second portion that is positioned differently from the first portion in the first direction;
the third linear pattern is electrically connected to ground via a third portion, and is connected to the fourth linear pattern at a fourth portion that is positioned differently from the third portion in the first direction;
the second and fourth portions are located at approximately central portions of the first and third linear patterns in the first direction ,
A noise suppression sheet, wherein the first and second linear patterns have cross-sectional shapes in which the pattern width increases toward the insulating substrate. a coupling pattern extending in a second direction perpendicular to the first direction and electrically connected to ground;
the first linear pattern is connected to the connecting pattern at the first portion and is disposed at an end in the second direction;
The noise suppression sheet according to claim 1 , wherein a connection pattern that connects the connection pattern and the first linear pattern has a round shape. The noise suppression sheet according to claim 1 , wherein the first and second linear patterns have a thickness greater than a thickness of the insulating substrate. The noise suppression sheet according to any one of claims 1 to 8 ,
A magnetic sheet;
a coil pattern disposed between the noise suppression sheet and the magnetic sheet. 10. The coil device according to claim 9 , wherein a pattern width of the first and second linear patterns is smaller than a skin depth of an electromagnetic field generated by a current flowing through the coil pattern and incident on the first and second linear patterns. 11. The coil device according to claim 9, wherein the conductor thickness of the first and second linear patterns is smaller than a skin depth of an electromagnetic field generated by a current flowing through the coil pattern and incident on the first and second linear patterns. 12. The coil device according to claim 9, wherein a separation distance between the coil pattern and the conductor pattern is generated by a current flowing through the coil pattern and is smaller than a skin depth of an electromagnetic field incident on the first and second linear patterns.

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