Coil component and wireless power transmission device including the same

Abstract

To shield radiation noise generated from a coil more effectively.SOLUTION: A coil component 1 includes: a planar spiral coil C1; a magnetic body 20 located on one side in the axial direction of the coil C1; and a conductive sheet 30 located on the other side in the axial direction of the coil C1. The conductive sheet 30 includes a solid transparent conductive film 32. The solid transparent conductive film 32 serves to shield unnecessary radiation noise. Radiation noise generated from the coil C1 is thus effectively shielded.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a coil component and a wireless power transmission device including the same. [Background technology]

[0002] Patent Document 1 discloses a technique for shielding radiation noise generated from a wireless charging module by providing a shielding layer with a comb-tooth structure between the wireless charging module including a coil and an electronic device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-214705 Summary of the Invention [Problem to be solved by the invention]

[0004] In this disclosure, a technique for more effectively shielding radiated noise generated from a coil is described. [Means for solving the problem]

[0005] A coil component according to one aspect of the present disclosure comprises a planar spiral coil, a magnetic body located on one axial side of the coil, and a conductive sheet located on the other axial side of the coil, the conductive sheet including a solid transparent conductive film. [Effects of the Invention]

[0006] According to the present disclosure, a technique for more effectively shielding radiation noise generated from a coil is provided. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 1 is a schematic cross-sectional view illustrating the structure of a coil component 1 according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic plan view showing the shape of the conductor pattern formed on one surface 11 of the substrate 10. As shown in FIG. [Figure 3] FIG. 3 is a schematic plan view showing the shape of the conductor pattern formed on the other surface 12 of the substrate 10. As shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view illustrating a first example of the structure of the conductive sheet 30. As shown in FIG. [Figure 5] FIG. 5 is a schematic cross-sectional view illustrating a second example of the structure of the conductive sheet 30. As shown in FIG. [Figure 6] FIG. 6 is a schematic plan view of the coil device 1 according to this embodiment as viewed from the Z direction. [Figure 7] 7(a) is a schematic cross-sectional view taken along line AA shown in FIG. 6, and FIG. 7(b) is a schematic cross-sectional view taken along line BB shown in FIG. [Figure 8] FIG. 8 is a graph showing the frequency characteristics of the electric field generated on the placement surface S shown in FIG. 1 when an alternating current is applied to the coil C1, and shows the characteristics when the conductive sheet 30 is not present. [Figure 9] FIG. 9 is a graph showing the relationship between the sheet resistance of the conductive sheet 30 and the noise level. [Figure 10] FIG. 10 is a schematic plan view of a coil device 1A according to a first modified example, as viewed from the Z direction. [Figure 11] FIG. 11 is a schematic plan view of a coil device 1B according to a second modified example, as viewed from the Z direction. [Figure 12] FIG. 12 is a schematic plan view of a coil device 1C according to a third modified example, as viewed from the Z direction. [Figure 13] FIG. 13 is a block diagram of a wireless power transmission device 60 using the coil device 1. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the technology according to the present disclosure will be described in detail with reference to the accompanying drawings.

[0009] FIG. 1 is a schematic cross-sectional view illustrating the structure of a coil component 1 according to an embodiment of the present disclosure.

[0010] As shown in FIG. 1 , the coil component 1 according to this embodiment includes a coil C1, a magnetic body 20 located on one axial side of the coil C1, and a conductive sheet 30 located on the other axial side of the coil C1. In the example shown in FIG. 1 , the magnetic body 20 covers almost the entire surface of the coil C1 from one axial side, and the conductive sheet 30 covers almost the entire surface of the coil C1 from the other axial side. The coil C1 is composed of coil patterns 100 and 200 provided on surfaces 11 and 12, respectively, of a substrate 10 made of a PET film or the like. For convenience of explanation, FIG. 1 shows gaps between the components constituting the coil component 1, but these components may be fixed to each other using an adhesive sheet. For example, one surface of the coil C1 may be adhesively fixed to the magnetic body 20 via an adhesive sheet (not shown), and the other surface of the coil C1 may be adhesively fixed to the conductive sheet 30 via an adhesive sheet (not shown).

[0011] The coil C1 functions, for example, as a power transmission coil for wireless power transmission. The coil axis direction of the coil C1 is the Z direction. The magnetic body 20, the coil C1, and the conductive sheet 30 are laminated in this order in the Z direction. The magnetic body 20 may be made of a sheet-like magnetic material having a relative permeability of 300 or more. When the power transmission frequency using the coil C1 is approximately 100 to 200 kHz, high inductance can be obtained by using a magnetic material having a relative permeability of 300 or more as the material for the magnetic body 20. On the other hand, when performing information communication using a coil, such as near-field communication (NFC), the communication frequency is generally in the MHz range (13.56 MHz for NFC), and using a magnetic material with a relative permeability of 300 or more would result in large losses, so it is not appropriate to use such a magnetic material.

[0012] During actual use, an electronic device 40 including a coil C2 that functions as a receiving coil for wireless power transmission is placed on a mounting surface S shown in Fig. 1. When the electronic device 40 is placed on the mounting surface S, the coil C1, which is a transmitting coil, and the coil C2, which is a receiving coil, are coupled together, thereby transmitting power wirelessly from the coil component 1 to the electronic device 40. The magnetic body 20 functions as a magnetic path for the magnetic flux generated by the coil C1. The conductive sheet 30 serves to shield unnecessary radiation noise generated by the coil C1.

[0013] FIG. 2 is a schematic plan view showing the shape of the conductor pattern formed on one surface 11 of the substrate 10. As shown in FIG.

[0014] As shown in Fig. 2, a planar spiral coil pattern 100 constituting a portion of the coil C1 and terminal electrodes E1 and E2 are formed on one surface 11 of the substrate 10. The coil pattern 100 is configured with six turns, consisting of turns 110, 120, 130, 140, 150, and 160, with turn 110 located on the outermost periphery and turn 160 located on the innermost periphery. Of these, turns 110, 120, 130, 140, and 150 are divided radially into four by three spiral slits. Meanwhile, turn 160 is divided radially into two by one spiral slit. As a result, turn 110 is divided into four parts into lines 111 to 114, turn 120 is divided into four parts into lines 121 to 124, turn 130 is divided into four parts into lines 131 to 134, turn 140 is divided into four parts into lines 141 to 144, turn 150 is divided into four parts into lines 151 to 154, and turn 160 is divided into two parts into lines 161 and 162.

[0015] Lines 111, 121, 131, 141, 151, and 161 are continuous lines wound in a spiral for six turns, and are located at the outermost periphery of each turn. Lines 112, 122, 132, 142, 152, and 162 are continuous lines wound in a spiral for six turns, and are located at the second outermost periphery of each turn. Lines 113, 123, 133, 143, and 153 are continuous lines wound in a spiral for five turns, and are located at the second innermost periphery of each turn. Lines 114, 124, 134, 144, and 154 are continuous lines wound in a spiral for five turns, and are located at the innermost periphery of each turn.

[0016] The outer peripheral ends of the lines 111 to 114 are commonly connected to the terminal electrode E1, while the inner peripheral ends of the lines 161, 162, 153, and 154 are connected to through-hole conductors 301 to 304 that penetrate the substrate 10, respectively.

[0017] Figure 3 is a schematic plan view showing the shape of the conductive pattern formed on the other surface 12 of the substrate 10, as viewed from one surface 11 of the substrate 10, i.e., as viewed through the substrate 10.

[0018] As shown in FIG. 3, a planar spiral coil pattern 200 that constitutes the remaining portion of the coil C1 is formed on the other surface 12 of the substrate 10. The basic pattern shape of the coil pattern 200 is the same as that of the coil pattern 100. The coil pattern 200 is a six-turn configuration consisting of turns 210, 220, 230, 240, 250, and 260, with turn 210 located on the outermost periphery and turn 260 located on the innermost periphery. Of these, turns 210, 220, 230, 240, and 250 are radially divided into four by three spiral slits. Meanwhile, turn 260 is radially divided into two by one spiral slit. As a result, turn 210 is divided into four parts into lines 211 to 214, turn 220 is divided into four parts into lines 221 to 224, turn 230 is divided into four parts into lines 231 to 234, turn 240 is divided into four parts into lines 241 to 244, turn 250 is divided into four parts into lines 251 to 254, and turn 260 is divided into two parts into lines 261 and 262.

[0019] Lines 211, 221, 231, 241, 251, and 261 are continuous lines wound spirally for six turns, and are located at the outermost periphery of each turn. Lines 212, 222, 232, 242, 252, and 262 are continuous lines wound spirally for six turns, and are located at the second outermost periphery of each turn. Lines 213, 223, 233, 243, and 253 are continuous lines wound spirally for five turns, and are located at the second innermost periphery of each turn. Lines 214, 224, 234, 244, and 254 are continuous lines wound spirally for five turns, and are located at the innermost periphery of each turn.

[0020] The outer peripheral ends of lines 211 to 214 are commonly connected to terminal electrode E2 via through-hole conductors. Meanwhile, the inner peripheral ends of lines 261, 262, 253, and 254 are connected to through-hole conductors 304, 303, 302, and 301, respectively. As a result, coil C1, which has a configuration in which four 11-turn lines are connected in parallel, is connected between terminal electrode E1 and terminal electrode E2. In this way, coil C1 is a planar spiral coil.

[0021] FIG. 4 is a schematic cross-sectional view illustrating a first example of the structure of the conductive sheet 30. As shown in FIG.

[0022] In the first example shown in FIG. 4, the conductive sheet 30 is composed of a substrate 31 made of a PET film or the like and a single-layer transparent conductive film 32 provided on the surface of the substrate 31 and supported by the substrate 31. The transparent conductive film 32 is a solid pattern formed on almost the entire surface of the substrate 31 and is composed of, for example, a thin film of indium tin oxide (ITO) with a thickness of less than 10 nm. The sheet resistance of the transparent conductive film 32 can be controlled by the film thickness; the thicker the film, the lower the sheet resistance. When the transparent conductive film 32 is composed of a thin film of indium tin oxide (ITO), the sheet resistance is approximately 100 Ω / □ when the film thickness is on the nanometer order (a few nm). An indium tin oxide (ITO) thin film with a nanometer-order thickness is nearly transparent to visible light, specifically, has a light transmittance of 80% or more.

[0023] FIG. 5 is a schematic cross-sectional view illustrating a second example of the structure of the conductive sheet 30. As shown in FIG.

[0024] In the second example shown in FIG. 5 , the conductive sheet 30 is composed of a substrate 31 made of a PET film or the like and a three-layer transparent conductive film 32 provided on the surface of the substrate 31 and supported by the substrate 31. The three-layer transparent conductive film 32 is a laminated film in which a first metal oxide film 32A, a metal film 32B containing silver or a silver alloy, and a second metal oxide film 32C are laminated in this order from the surface side of the substrate 31, forming a solid pattern formed over almost the entire surface of the substrate 31. The first metal oxide film 32A and the second metal oxide film 32C are made of zinc oxide, ITO, or the like, and sandwich the metal film 32B containing silver or a silver alloy from above and below to prevent oxidation of the metal film 32B. The first metal oxide film 32A and the second metal oxide film 32C may also be conductive.

[0025] In the second example shown in FIG. 5, the sheet resistance of the transparent conductive film 32 can be controlled by the film thickness of the metal film 32B, and the thicker the metal film 32B, the lower the sheet resistance. In the second example shown in FIG. 5, by setting the overall film thickness of the transparent conductive film 32 to the nanometer order (several nanometers), the sheet resistance is approximately 1 to 10 Ω / □. The stacked film of the first metal oxide film 32A, the metal film 32B containing silver or a silver alloy, and the second metal oxide film 32C, each having a nanometer order film thickness, is nearly transparent to visible light, specifically, has a light transmittance of 80% or more. Increasing the film thickness of the metal film 32B reduces the sheet resistance to 4 Ω / □ or less.

[0026] Fig. 6 is a schematic plan view of the coil device 1 according to this embodiment as viewed from the Z direction. Fig. 7(a) is a schematic cross-sectional view taken along line AA shown in Fig. 6, and Fig. 7(b) is a schematic cross-sectional view taken along line BB shown in Fig. 6.

[0027] 6, 7(a), and 7(b), the substrate 10 is sandwiched between the magnetic body 20 and the conductive sheet 30 in the Z direction, and the entire surface of the substrate 10 is covered with the magnetic body 20 and the conductive sheet 30. Therefore, the entire coil C1 is covered with the magnetic body 20 and the conductive sheet 30. By covering the entire coil C1 with the magnetic body 20, more magnetic flux passes through the magnetic body 20, and the inductance of the coil C1 is increased. Furthermore, by covering the entire coil C1 with the conductive sheet 30, radiation noise is more efficiently shielded.

[0028] In particular, as shown in FIG. 7( a), the outer peripheral edge D2 of the main body 34 of the transparent conductive film 32 included in the conductive sheet 30 may be located outside the outer peripheral edges D1 of the outermost lines 111, 211 of the outermost turns 110, 210 of the coil C1, and inside the outer peripheral edge D3 of the magnetic body 20, when viewed from the axial Z direction. In this case, the outer peripheral region of the transparent conductive film 32 included in the conductive sheet 30 faces the magnetic body 20 without the coil C1 in between. By designing the sizes and positional relationships of the substrate 10, magnetic body 20, and conductive sheet 30 in this manner, even if some assembly variation occurs during assembly, the conductive sheet 30 will not protrude in plan from the magnetic body 20, resulting in a change in product size, or the substrate 10 protruding in plan from the conductive sheet 30, resulting in a decrease in shielding effect.

[0029] 6, 7(a), and 7(b), the conductive sheet 30 is laminated on the substrate 10 on which the coil C1 is formed so that the transparent conductive film 32 faces the coil C1. As a result, the outermost layer of the coil component 1 in the +Z direction is formed by the substrate 31, and therefore the transparent conductive film 32 can be protected.

[0030] In the example shown in FIG. 6, a protrusion 33 is provided on the conductive sheet 30. The protrusion 33 is a portion that extends beyond the magnetic body 20 in a plan view. As shown in the example shown in FIG. 7(b), a connecting conductor 50, such as a metal pin, is connected to the transparent conductive film 32 located at the protrusion 33. The portion of the conductive sheet 30 that overlaps the magnetic body 20 constitutes a main body 34. The main body 34 and the protrusion 33 are connected and integral with each other. The connecting conductor 50 is connected to ground GND, thereby grounding the transparent conductive film 32. Grounding the transparent conductive film 32 to ground can achieve a higher shielding effect. In the example shown in FIG. 7(b), the transparent conductive film 32 and the connecting conductor 50 are connected via a conductive adhesive 51 and a conductive tape 52. The conductive adhesive 51 contacts the transparent conductive film 32, and the conductive tape 52 contacts the connecting conductor 50. In this way, by using the conductive adhesive 51 in the part that comes into contact with the transparent conductive film 32, high heat is not applied during connection, as is the case when solder is used, and therefore it is possible to prevent deterioration of the transparent conductive film 32 and a decrease in reliability due to heat.

[0031] Next, the effects of the conductive sheet 30 will be described.

[0032] FIG. 8 is a graph showing the frequency characteristics of the electric field generated on the placement surface S shown in FIG. 1 when an alternating current is applied to the coil C1, and shows the characteristics when the conductive sheet 30 is not present.

[0033] In the example shown in Figure 8, the fundamental frequency F1 of the AC applied to coil C1 is approximately 128 kHz, and a strong peak appears. Frequency F2 is a noise component generated by an inverter included in the power supply circuit for generating the AC. Frequency F3 is a third harmonic component of fundamental frequency F1, and frequency F5 is a fifth harmonic component of fundamental frequency F1. As shown in Figure 8, when conductive sheet 30 is not present, large peaks appear at frequencies F2, F3, and F5.

[0034] FIG. 9 is a graph showing the relationship between the sheet resistance of the conductive sheet 30 and the noise level. Characteristic N0 indicates the noise level when the conductive sheet 30 is not present. Characteristic N1 indicates the noise level when a single-layer thin film of indium tin oxide (ITO) having a sheet resistance of 96 Ω / □ is used as the transparent conductive film 32. Characteristic N2 indicates the noise level when a laminate film of a first metal oxide film 32A, a metal film 32B containing silver or a silver alloy, and a second metal oxide film 32C having a sheet resistance of 10 Ω / □ is used as the transparent conductive film 32. Characteristic N3 indicates the noise level when a laminate film of a first metal oxide film 32A, a metal film 32B containing silver or a silver alloy, and a second metal oxide film 32C having a sheet resistance of 4 Ω / □ is used as the transparent conductive film 32.

[0035] 9, it can be seen that the electric field levels at frequencies F2 (255 kHz), F3 (385 kHz), and F5 (635 kHz), which are noise components, are reduced by using the conductive sheet 30. The noise levels at frequencies F2, F3, and F5 are more significantly suppressed as the sheet resistance of the transparent conductive film 32 decreases.

[0036] Here, if the sheet resistance of the transparent conductive film 32 is 3 Ω / □ or higher, the reduction in the electric field level of the fundamental frequency F1 is slight and does not pose a practical problem for wireless power transmission. However, if the sheet resistance of the transparent conductive film 32 is too low, for example, less than 1 Ω / □, not only may a significant reduction in the electric field level of the fundamental frequency F1 occur, but also, if a metal foreign object detection function is provided, the transparent conductive film 32 may be erroneously detected as a metal foreign object. To prevent this, the sheet resistance of the transparent conductive film 32 may be 1 Ω / □ or higher, or to provide a larger margin, 3 Ω / □ or higher. Although it depends on the material of the transparent conductive film 32, if the light transmittance is less than 80%, the sheet resistance will almost always be less than 1 Ω / □.

[0037] As described above, the coil component 1 according to this embodiment has the conductive sheet 30 having the transparent conductive film 32 disposed on the side opposite the magnetic body 20 as viewed from the coil C1, and therefore can reduce radiation noise without significantly impeding the electric field component at the fundamental frequency F1. In other words, as described in Patent Document 1, conventionally, in order to shield radiation noise without impeding the electromagnetic field of the fundamental frequency, it was necessary to form a comb-tooth structure shielding layer by patterning. However, this embodiment uses the transparent conductive film 32 that is thin enough not to impede the electromagnetic field of the fundamental frequency, and therefore can reduce radiation noise with a simple solid configuration without patterning.

[0038] In the above embodiment, the entire surface of the coil C1 is covered with the conductive sheet 30, but it is not necessary that a portion of the coil C1 is not covered with the conductive sheet 30.

[0039] Fig. 10 is a schematic plan view of a coil device 1A according to a first modified example, as viewed from the Z direction. In Fig. 10, hatched portions indicate coil C1, with reference symbol D1 indicating the outer edges of the outermost peripheral lines 111 and 211 and reference symbol D4 indicating the inner edges of the innermost peripheral lines 162 and 262. The same applies to Figs. 11 and 12, which will be described below.

[0040] In a coil device 1A according to a first modification shown in FIG. 10, a slit SL1 is provided in a transparent conductive film 32 provided on the surface of a substrate 31. In a plan view, the slit SL1 extends in the Y direction from the central portion of the coil C1 in the X direction. The end of the slit SL1 in the -Y direction reaches the edge of the transparent conductive film 32, dividing the transparent conductive film 32 at this portion. On the other hand, the end of the slit SL1 in the +Y direction does not reach the edge of the transparent conductive film 32, leaving the transparent conductive film 32 undivided and continuous at this portion. By providing such a slit SL1 in the transparent conductive film 32, eddy currents are suppressed by the slit SL1, thereby improving power transmission efficiency and reducing the likelihood of the transparent conductive film 32 being erroneously detected as a metallic foreign object. Furthermore, by narrowing the width W of the slit SL1 sufficiently, for example, to approximately 50 μm to 500 μm, the reduction in shielding effect is minimized. These effects can be obtained even when the transparent conductive film 32 is not connected to ground GND and is in a floating state.

[0041] FIG. 11 is a schematic plan view of a coil device 1B according to a second modified example, as viewed from the Z direction.

[0042] In a coil component 1B according to a second modification shown in FIG. 11, a transparent conductive film 32 provided on the surface of a substrate 31 is divided into two regions 321 and 322. The regions 321 and 322 are arranged side by side in the X direction, and a slit SL2 located between the regions 321 and 322 extends in the Y direction from the center portion of the coil C1 in the X direction in a plan view. Even when the transparent conductive film 32 is divided into multiple regions in this way, by sufficiently narrowing the width W of the slit SL2 to, for example, approximately 50 μm to 500 μm, it is possible to suppress eddy currents while minimizing the reduction in shielding effectiveness. These effects can be obtained even when the transparent conductive films 321 and 322 are not connected to ground GND and are in a floating state. The number of divisions of the transparent conductive film 32 does not need to be two; it may be three or more.

[0043] FIG. 12 is a schematic plan view of a coil device 1C according to a third modified example, as viewed from the Z direction.

[0044] In a coil device 1C according to a third modification shown in FIG. 12, the substrate 31 is divided into two regions 311 and 312, and regions 321 and 322 of the transparent conductive film 32 are formed in the regions 311 and 312, respectively. In this manner, the substrate 31 itself may be divided into multiple regions. This increases the degree of freedom in design. Even in this case, by sufficiently narrowing the width W of the slit SL3 located between the regions 321 and 322, it is possible to suppress eddy currents while minimizing the reduction in shielding effect. The number of divisions of the substrate 31 does not need to be two, and it may be three or more.

[0045] FIG. 13 is a block diagram of a wireless power transmission device 60 using the coil component 1 according to this embodiment.

[0046] 13 includes a coil component 1 having a coil C1, a magnetic body 20, and a conductive sheet 30, a power transmission circuit 61 connected to the coil C1, and a control circuit 62 that controls the power transmission circuit 61. When an AC current is applied to the coil C1 by the power transmission circuit 61, the coil C1, which is a power transmission coil, and the coil C2, which is a power receiving coil, are coupled together. In this embodiment, the conductive sheet 30 is disposed between the coil C1 and the coil C2, thereby reducing unnecessary radiation noise generated from the coil C1.

[0047] The above describes embodiments of the technology according to the present disclosure, but the technology according to the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the technology, and it goes without saying that these modifications are also included within the scope of the technology according to the present disclosure.

[0048] For example, the coil C1 may be formed by winding a coated conductor wire in a planar spiral shape instead of a conductor pattern formed on the surface of the substrate. Furthermore, the conductor patterns provided on the surfaces 11 and 12 of the substrate 10 may be provided on the surfaces 11 and 12 of the substrate 10 with another material layer containing a resin interposed therebetween.

[0049] Furthermore, the coil C1 may function as a power receiving coil for wireless power transmission instead of a power transmitting coil for wireless power transmission, and the coil device 1 may be housed in the electronic device 40. In this case, the conductive sheet 30, the coil C1, and the magnetic body 20 may be laminated in this order from the power transmitting coil side for wireless power transmission. The conductive sheet 30 is disposed between the power transmitting coil and the power receiving coil for wireless power transmission.

[0050] The technology according to the present disclosure includes, but is not limited to, the following configuration examples.

[0051] A coil component according to one aspect of the present disclosure includes a planar spiral coil, a magnetic body located on one axial side of the coil, and a conductive sheet located on the other axial side of the coil, the conductive sheet including a solid transparent conductive film, whereby unnecessary radiation noise is shielded by the transparent conductive film.

[0052] In the coil component, the transparent conductive film may be grounded, which makes it possible to obtain a higher shielding effect.

[0053] In the coil component, the transparent conductive film may be made of indium tin oxide (ITO), which makes it possible to reduce material costs.

[0054] In the coil component, the transparent conductive film may be a laminated film in which a first metal oxide film, a metal film containing silver or a silver alloy, and a second metal oxide film are laminated in this order, thereby making it possible to further reduce the sheet resistance of the transparent conductive film.

[0055] In the coil component described above, the sheet resistance of the transparent conductive film may be 10 Ω / □ or less. This makes it possible to obtain a high shielding effect. Furthermore, the sheet resistance of the transparent conductive film may be 4 Ω / □ or less. This makes it possible to obtain a higher shielding effect. Furthermore, the sheet resistance of the transparent conductive film may be 1 Ω / □ or more. This prevents the electric field of the fundamental frequency from being significantly obstructed.

[0056] In the coil component described above, the transparent conductive film may include a main body portion, and the outer peripheral edge of the main body portion of the transparent conductive film may be located outside the outer peripheral edge of the outermost turn of the coil and inside the outer peripheral edge of the magnetic body when viewed in the axial direction, thereby increasing the margin during assembly.

[0057] The coil component may further include a connection conductor that connects the transparent conductive film to ground, the transparent conductive film further including a protrusion that is connected to the main body and extends outward beyond the magnetic body, and the connection conductor may be bonded to the protrusion of the transparent conductive film via a conductive adhesive, thereby reducing damage to the main body of the transparent conductive film.

[0058] In the coil component, the transparent conductive film may have slits, which makes it possible to reduce eddy currents occurring in the transparent conductive film.

[0059] In the coil component, the transparent conductive film may be divided into a plurality of regions, which makes it possible to reduce eddy currents occurring in the transparent conductive film.

[0060] In the coil component described above, the conductive sheet may include a substrate that supports the transparent conductive film, and the conductive sheet may be laminated on the coil so that the transparent conductive film faces the coil, thereby protecting the transparent conductive film.

[0061] A wireless power transmission device according to one aspect of the present disclosure includes any one of the coil components described above and a power transmission circuit connected to the coil, thereby making it possible to provide a wireless power transmission device with low radiation noise. [Explanation of symbols]

[0062] 1,1A~1C Coil parts 10 Base material 11,12 surface 20 Magnetic material 30 Conductive sheet 31 Base material 32 Transparent conductive film 32A First metal oxide film 32B Metal film 32C Second metal oxide film 33 Protrusion 34 Main body 40 Electronic equipment 50 Connecting conductor 51 Conductive adhesive 52 Conductive tape 60 Wireless power transmission device 61 Power Transmission Circuit 62 Control circuit 100,200 coil patterns 110,120,130,140,150,160,210,220,230,240,250,260 turns 111~114, 121~124, 131~134, 141~144, 151~154, 161, 162, 211~214, 221~224, 231~234, 241~244, 251~254, 261, 262 Lines 301~304 Through-hole conductors 311,312,321,322 area C1, C2 coils D1~D3 outer edge D4 inner edge E1,E2 terminal electrode S Placement surface SL1~SL3 slits

Claims

1. a planar spiral coil; a magnetic body located on one side of the coil in the axial direction; a conductive sheet located on the other side of the coil in the axial direction; Equipped with The conductive sheet includes a solid transparent conductive film. Coil parts.

2. The transparent conductive film is grounded. The coil component according to claim 1 .

3. The transparent conductive film is made of indium tin oxide (ITO). The coil component according to claim 1 .

4. the transparent conductive film is composed of a laminated film in which a first metal oxide film, a metal film containing silver or a silver alloy, and a second metal oxide film are laminated in this order; The coil component according to claim 1 .

5. The transparent conductive film has a sheet resistance of 10 Ω / □ or less. The coil component according to claim 4 .

6. the sheet resistance of the transparent conductive film is 4 Ω / □ or less; The coil component according to claim 5 .

7. The transparent conductive film has a sheet resistance of 1 Ω / □ or more. The coil component according to claim 6 .

8. the transparent conductive film includes a main body portion, an outer peripheral edge of the main body portion of the transparent conductive film is located outside an outer peripheral edge of an outermost turn of the coil and inside an outer peripheral edge of the magnetic body when viewed in the axial direction; The coil component according to claim 1 .

9. a connection conductor for connecting the transparent conductive film to a ground; the transparent conductive film further includes a protrusion connected to the main body and extending outward beyond the magnetic body; the connecting conductor is bonded to the protruding portion of the transparent conductive film via a conductive adhesive; The coil component according to claim 8 .

10. The transparent conductive film has a slit. The coil component according to claim 1 .

11. The transparent conductive film is divided into a plurality of regions. The coil component according to claim 1 .

12. the conductive sheet includes a substrate that supports the transparent conductive film, the conductive sheet is laminated on the coil so that the transparent conductive film faces the coil; The coil component according to claim 1 .

13. The coil component according to any one of claims 1 to 12; a power transmission circuit connected to the coil.

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