Patent ID: 12237696

DETAILED DESCRIPTION OF THE EMBODIMENTS

An object of the present disclosure is to provide an antenna device providing a wide coverage area and communication distance.

Preferred embodiments of the present disclosure will be explained below in detail with reference to the accompanying drawings.

FIG.1is a schematic cross-sectional view illustrating the configuration of an antenna device1according to a first embodiment of the present disclosure.

As illustrated inFIG.1, the antenna device1according to the first embodiment includes a first substrate10, a first coil100formed on one surface11of the first substrate10, and a second coil200formed on the other surface12of the first substrate10. The first substrate10is a film made of an insulating resin material such as PET (Polyethylene Terephthalate) or PI (Polyimide).

The first coil100functions as an antenna coil for performing near-field communication (NFC). The second coil200functions as a booster coil for extending the communication distance. The surface12of the first substrate10is covered with a magnetic member30, whereby inductance is enhanced. The magnetic member30may be a sheet-like material. The magnetic member30may be coated on the surface12of the first substrate10.

FIG.2is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface11of the first substrate10.

As illustrated inFIG.2, the first coil100, conductor patterns41to43, and a first capacitor electrode pattern61are formed on the surface11of the first substrate10. These conductor patterns are each formed of a conductive material such as copper, aluminum, or an alloy thereof. The same applies to other conductor patterns to be described later. The first substrate10has a rectangular shape with a size larger in the X-direction (first direction) than that in the Y-direction (second direction).

The first coil100is a coil pattern wound in about three turns and includes a first turn110as the innermost turn, a second turn120as the second turn counted from the innermost (or outermost) periphery, and a third turn130as the outermost turn. The first coil100has a coil axis extending in the Z-direction. The outer peripheral end of the first coil100is connected to the conductor pattern41. The inner peripheral end of the first coil100is connected to the conductor pattern42through via conductors51,52penetrating the first substrate10and a conductor pattern44to be described later. The end portions of the respective conductor patterns41and42constitute a pair of signal terminals connected to the first coil100.

The first turn110, second turn120, and third turn130are wound in a substantially rectangular shape. The first turn110has a shape with a size larger in the Y-direction than that in the X-direction. On the other hand, the second and third turns120and130have a shape with a size larger in the X-direction than that in the Y-direction.

The first turn110includes sections111,113, and115extending in the X-direction and sections112and114extending in the Y-direction. When the inner peripheral end is set as the starting point of winding, the first turn110is wound to form the sections111,112,113,114, and115in this order. The section113has a length of W1 in the X-direction, and the sections112and114each have a length of W0 in the Y-direction. The length W1 is smaller than the length W0. The length W1 corresponds to the opening width of the first turn110in the X-direction, and the length W0 corresponds to the opening width of the first turn110in the Y-direction.

The second turn120includes sections121,123, and125extending in the X-direction and sections122and124extending in the Y-direction. When a connection portion with the first turn110is set as the starting point of winding, the second turn120is wound to form the sections121,122,123,124, and125in this order. The interval between the section122of the second turn120and the section112of the first turn110in the X-direction is W2. Similarly, the interval between the section124of the second turn120and the section114of the first turn110in the X-direction is also W2. Accordingly, the length of the section123in the X-direction (or the opening width of the second turn120in the X-direction) is obtained by adding, to the sum of W1+W2+W2, the pattern widths of the sections112and114of the first turn110in the X-direction. The interval W2 may be substantially equal to the length W1. The interval between the section123of the second turn120and the section113of the first turn110in the Y-direction is W4. Similarly, the interval between the section121of the second turn120and the section111of the first turn110in the Y-direction, and the interval between the section125of the second turn120and the section115of the first turn110in the Y-direction are each also W4. The interval W4 is sufficiently smaller than the interval W2 and may be the minimum space for the conductor pattern that can be formed on the surface11of the first substrate10. In this case, the length of each of the sections122and124in the Y-direction (or the opening width of the second turn120in the Y-direction), which is substantially equal to W0, is obtained by adding, to the sum of W0+W4+W4, the pattern width of the section111or115of the first turn110in the Y-direction and the pattern width of the section113of the first turn110in the Y-direction.

The third turn130includes sections131,133, and135extending in the X-direction and sections132and134extending in the Y-direction. When a connection point with the second turn120is set as the starting point of winding, the third turn130is wound to form the sections131,132,133,134, and135in this order. The interval between the section132of the third turn130and the section122of the second turn120in the X-direction is W3. Similarly, the interval between the section134of the third turn130and the section124of the second turn120in the X-direction is also W3. Accordingly, the length of the section133in the X-direction (or the opening width of the third turn130in the X-direction) is obtained by adding, to the sum of W1+W2+W2+W3+W3, the pattern widths of sections112and114of the first turn110in the X-direction and the pattern widths of sections122and124of the second turn120in the X-direction. The interval W3 may be substantially equal to the length W1 and interval W2 (i.e., W1≈W2≈W3). The interval between the section133of the third turn130and the section123of the second turn120in the Y-direction is W4. Similarly, the interval between the section131of the third turn130and the section121of the second turn120in the Y-direction and the interval between the section135of the third turn130and the section125of the second turn120in the Y-direction are each also W4. Accordingly, the length of each of the sections132and134in the Y-direction (or the opening width of the third turn130in the Y-direction) is obtained by adding, to the sum of W0+W4+W4+W4+W4, the pattern width of the section111or115of the first turn110in the Y-direction, the pattern width of the section113of the first turn110in the Y-direction, the pattern width of the section121or125of the second pattern120in the Y-direction, and the pattern width of the section123in the Y-direction and is substantially W0 when the interval W4 and the coil pattern width are very small. The term “substantially equal” used here includes variations due to manufacturing error or other factors. The range of error may be within 5%, for example.

As described above, the first coil100is configured such that the intervals W2 and W3 (first interval) between the turns in the X-direction are larger than the interval W4 (second interval) between the turns in the Y-direction. This allows the coverage area to be extended in the X-direction. Therefore, the antenna device1according to the resent embodiment is suitable for use requiring a coverage area having such characteristics.

The conductor pattern43formed on the surface11of the first substrate10has one end connected to the first capacitor electrode pattern61and the other end connected to a via conductor53penetrating the first substrate10. The first capacitor electrode pattern61is disposed outside the first coil100and has a plurality of conductor patterns which are arranged in the Y-direction and extend in the X-direction.

FIG.3is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface12of the first substrate10.

As illustrated inFIG.3, a second coil200, a conductor pattern44, and a second capacitor electrode pattern62are formed on the surface12of the first substrate10. The conductor pattern44connects the via conductors51and52. The second coil200is wound in about one turn along outer peripheral sides13to16of the first substrate10. Thus, the second coil200has a shape with a size larger in the X-direction than that in the Y-direction. The second coil200includes sections201,203, and205extending in the X-direction and sections202and204extending in the Y-direction. When one end of the second coil200connected to the via conductor53is set as the starting point of winding, the second coil200is wound to form the sections201,202,203,204, and205in this order.

The planar position of the second coil200as viewed from the surface11side of the first substrate10is denoted by the dashed line inFIG.2. As illustrated inFIG.2, the second coil200is disposed outside the first coil100as viewed in the Z-direction. The inter-coil distance in the X-direction between the section132constituting a first outer edge of the first coil100and the section202constituting a first inner edge of the second coil200is W5. The inter-coil distance in the X-direction between the section134constituting a second outer edge of the first coil100and the section204constituting a second inner edge of the second coil200is also W5. The inter-coil distance in the Y-direction between the section131constituting a third outer edge of the first coil100and the section201constituting a third inner edge of the second coil200is W6. The inter-coil distance in the Y-direction between the section133constituting a fourth outer edge of the first coil100and the section203constituting a fourth inner edge of the second coil200is also W6. The inter-coil distances W5 and W6 are larger than the interval W4. The inter-coil distances W5 and W6 may be smaller than the intervals W1 to W3. The inter-coil distances W5 and W6 may be the same as or different from each other.

As illustrated inFIG.1, the second coil200and the magnetic member30overlap each other. The second coil200has a size slightly smaller than the outer size of the magnetic member30, and a distance L between the outer edge of the second coil200and the outer edge of the magnetic member30is smaller than the inter-coil distances W5 and W6. That is, the second coil200is disposed along the outer periphery of the magnetic member30so as to overlap the magnetic member30as viewed in the Z-direction.

One end of the second coil200is connected to the first capacitor electrode pattern61formed on the surface11of the first substrate10through the via conductor53, and the other end thereof is connected to the second capacitor electrode pattern62formed on the surface12of the first substrate10. The first and second capacitor electrode patterns61and62are both a terminated conductor pattern, and thus both ends of the second coil200are opened.

The second capacitor electrode pattern62includes a plurality of conductor patterns71extending in the X-direction, a plurality of conductor patterns72arranged in the X-direction along each of the conductor patterns71, and a conductor pattern73extending in the Y-direction so as to connect its corresponding conductor patterns71and72. Each of the plurality of conductor patterns72overlaps its corresponding first capacitor electrode pattern61through the first substrate10. As a result, a capacitor is formed by the first and second capacitor electrode patterns61and62and the first substrate10positioned therebetween. The capacitance of the capacitor can be finely adjusted by removing some conductor patterns73by trimming.

As described above, in the antenna device1according to the present embodiment, the first coil100functioning as an antenna coil has the first, second, and third turns110,120, and130, and the outer sizes thereof are substantially the same in the Y-direction, while significantly different in the X-direction, thereby allowing a coverage area to be extended in the X-direction. In addition, by making the intervals W2 and W3 between the turns in the X-direction substantially the same as the opening width W1 in the X-direction of the first turn110, communication can be performed properly irrespective of the position of a communication target device in the X-direction, which can prevent the occurrence of a so-called null point.

Further, the second coil200functioning as a booster coil is disposed outside the first coil100, and the intervals W5 and W6 between the first and second coils100and200are larger than the interval W4 between the turns of the first coil100in the Y-direction. This suppresses excessive coupling between the first and second coils100and200to allow each of the first and second coils100and200to be adjusted so as to have an optimum resonant frequency, whereby a communication distance can be extended. Further, making the intervals W5 and W6 smaller than the intervals W2 and W3 between the turns of the first coil100in the X-direction allows coupling between the first and second coils100and200to be ensured to some extent and allows communication to be performed through the second coil200even when a communication target device is positioned outside the first coil100as viewed in the Z-direction.

The following describes a second embodiment of the present disclosure.

As illustrated inFIG.1, an antenna device2according to the second embodiment includes a first substrate10, a first coil100formed on one surface11of the first substrate10, and a second coil300formed on the other surface12of the first substrate10. The surface12of the first substrate10is covered with a magnetic member30. The first coil100functions as an antenna coil for performing near-field communication (NFC). The second coil300functions as a booster coil for extending a communication distance.

FIG.4is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface11of the first substrate10in the second embodiment.

As illustrated inFIG.4, the first coil100, conductor patterns41and42, and second capacitor electrode patterns63to65are formed on the surface11of the first substrate10. The first coil100has the same configuration as that described in the first embodiment, so overlapping description will be omitted.

The second capacitor electrode patterns63to65are disposed respectively along outer peripheral sides13to15of the first substrate10and are mutually connected in series. One end of the series pattern composed of the second capacitor electrode patterns63to65is connected to a via conductor54penetrating the first substrate10, and the other end thereof is opened.

FIG.5is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface12of the first substrate10in the second embodiment.

As illustrated inFIG.5, a second coil300, a conductor pattern44, and first capacitor electrode patterns66to68are formed on the surface12of the first substrate10. The second coil300is wound in about 1.5 turns along outer peripheral sides13to16of the first substrate10. Thus, the second coil300has a shape with a size larger in the X-direction than that in the Y-direction. The second coil300includes sections301,303,305,307extending in the X-direction and sections302,304, and306extending in the Y-direction. When one end of the second coil300connected to the via conductor54is set as the starting point of winding, the second coil300is wound to form the sections301,302,303,304,305,306, and307in this order. The end portion of the section307constituting the other end of the second coil300is opened. As in the first embodiment, the second coil300is disposed outside the first coil100as viewed from the surface11side of the first substrate10.

One end of the second coil300is connected to the second capacitor electrode patterns63to65formed on the surface11of the first substrate10through the via conductor54. Further, the second coil300is connected with the first capacitor electrode patterns66to68along the sections305to307. The first capacitor electrode patterns66to68include a plurality of conductor patterns72disposed at mutually different positions along the sections305to307and a conductor pattern73connecting the conductor pattern72and the second coil300. The plurality of conductor patterns72overlap their corresponding second capacitor electrode patterns63to65through the first substrate10. As a result, a capacitor is formed by the second capacitor electrode patterns63to65, first capacitor electrode patterns66to68, and the first substrate10positioned therebetween. The capacitance of the capacitor can be finely adjusted by removing some conductor patterns73by trimming.

In addition to the same effects as obtained by the antenna device1according to the first embodiment, the antenna device2according to the present embodiment has the following effects. That is, since the capacitor electrode patterns63to68are disposed in a distributed manner, design freedom is enhanced, and, even when the antenna device2is used overlapping a power transmission coil for a wireless power transmission device, interference between magnetic flux generated from the power transmission coil and capacitor electrode patterns63to68is reduced, making it possible to suppress an increase in the AC resistance of the power transmission coil. In addition, the first capacitor electrode patterns66to68connected to the second coil300are disposed between the first and second coils100and300so as to protrude inside the second coil300, so that, as compared with when the first capacitor electrode patterns66to68are disposed between the sections301and305of the second coil300, it is possible to carry out trimming of the conductor pattern of the second coil300easily while preventing unintended breakage thereof. Furthermore, since the interval between the turns of the second coil300can be reduced, when a communication target device is positioned outside the first coil100as viewed in the Z-direction, coupling between the second coil300and the communication target device can be enhanced.

FIG.6is a schematic cross-sectional view illustrating the configuration of a wireless power transmission device3according to a third embodiment of the present disclosure.

As illustrated inFIG.6, the wireless power transmission device3according to the third embodiment includes first and second substrates10and20, a noise suppressing pattern N formed on one surface11of the first substrate10, first and second coils100and300formed on the other surface12of the first substrate10, and a plurality of power transmission coils400formed on one and the other surfaces21and22of the second substrate20. Like the first substrate10, the second substrate20is a film made of an insulating resin material such as PET (Polyethylene Terephthalate) or PI (Polyimide).

The first coil100functions as an antenna coil for performing near-field communication (NFC). The second coil300functions as a booster coil for extending a communication distance. The power transmission coil400is used for power transmission in wireless power transmission. The surface22of the second substrate20is covered with a magnetic member30, whereby inductance is enhanced.

FIG.7is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface11of the first substrate10in the third embodiment.

As illustrated inFIG.7, the noise suppressing pattern N, conductor patterns47and48, and second capacitor electrode patterns63to65are formed on the surface11of the first substrate10. The second capacitor electrode patterns63to65illustrated inFIG.7are basically the same in position and shape as the second capacitor electrode patterns63to65illustrated inFIG.4, so overlapping description will be omitted.

The noise suppressing pattern N includes a plurality of linear patterns81extending in the Y-direction, a connection pattern82extending in the X-direction and connecting the plurality of linear patterns81, and a lead-out pattern83connected to the connection pattern82and constituting a terminal electrode. In the example illustrated inFIG.7, the plurality of linear patterns81linearly extend in the Y-direction and arranged in the X-direction at a constant pitch, but not limited to this. For example, the plurality of linear patterns81may extend in the Y-direction while meandering. Alternatively, the extending direction of the plurality of linear patterns81may be inclined at a predetermined angle with respect to the Y-direction. Further alternatively, the arrangement pitch between the plurality of linear patterns81in the X-direction may differ depending on the planar position.

FIG.8is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface12of the first substrate10in the third embodiment.

As illustrated inFIG.8, in addition to the first coil100and second coil300, conductor patterns41,42,45,46, and74and first capacitor electrode patterns66to68are formed on the surface12of the first substrate10. The conductor pattern74is a pattern for connecting the second capacitor electrode patterns63to65to a via conductor54through via conductors75and76. The structure of the first coil100is the same as that of the first embodiment, so overlapping description will be omitted. Similarly, the structures of the second coil300and first capacitor electrode patterns66to68are the same as those of the second embodiment, so overlapping description will be omitted. As described above, in the present embodiment, the first and second coils100and300are formed on the same surface of the first substrate10.

The conductor pattern41is connected to the conductor pattern45through the conductor pattern47and a via conductor57. Similarly, the conductor pattern42is connected to the conductor pattern46through a via conductor56, the conductor pattern48, and a via conductor58. The end portions of the respective conductor patterns45and46constitute a pair of signal terminals connected to the first coil100. Also in the present embodiment, a capacitor is formed by the second capacitor electrode patterns63to65, first capacitor electrode patterns66to68, and the first substrate10positioned therebetween.

FIG.9is a schematic plan view for explaining the pattern shapes of conductor patterns formed on the surface21of the second substrate20in the third embodiment.

As illustrated inFIG.9, a plurality of (seven in the example illustrated inFIG.9) power transmission coils400are formed on the surface21of the second substrate20. Similarly, a plurality of power transmission coils400are formed on the surface22of the second substrate20. Two power transmission coils400overlapping each other on both the front and back sides are connected to each other at their inner peripheral ends. By forming, on the second substrate20, the plurality of power transmission coils400whose coil axes are different in planar position from one another, wireless power transmission can be achieved efficiently irrespective of the planar position of a power receiving coil.

As described above, the first coil100, second coil300, and second capacitor electrode patterns63to68illustrated inFIGS.8and9have basically the same configuration as those in the antenna device2according to the second embodiment. In the present embodiment, an antenna device having such a configuration and the plurality of power transmission coils400are disposed to overlap each other in the Z-direction which is the coil axis direction.

FIG.10is a block diagram illustrating the wireless power transmission device3according to the present embodiment and a mobile communication device4to be wirelessly connected thereto.

As illustrated inFIG.10, the wireless power transmission device3according to the present embodiment includes a power transmission circuit91connected to the power transmission coil400, a communication circuit92connected to the first coil100, and a control circuit93connected to the power transmission circuit91and communication circuit92. The second coil200or300functioning as a booster coil is disposed outside the first coil100. With this configuration, data transmitted and received through a communication line94can be communicated through the first coil100as an antenna coil for NFC, and electric power supplied from a power supply95can be wirelessly transmitted through the power transmission coil400for wireless power transmission.

The mobile communication device4such as a smartphone includes a power receiving coil600, an antenna coil500for NFC, a power receiving circuit96connected to the power receiving coil600, a communication circuit97connected to the antenna coil500, and a battery98connected to the power receiving circuit96and communication circuit97. The power receiving coil600is coupled to the power transmission coil400, and the antenna coil500as a communication coil is coupled to the first coil100as a communication coil. To enhance coupling between these coils, a magnetic member31is provided in the mobile communication device4. With this configuration, data transmitted and received through a communication line99can be communicated through the antenna coil500, and electric power that the power receiving coil600has received is fed, through the power receiving circuit96, to the battery98for charging. The battery98serves as an operation power supply for the communication circuit97and the like.

The wireless power transmission device3according to the present embodiment has the noise suppressing pattern N disposed between the power transmission coil400and a placing surface3A of a housing thereof, thereby reducing radiation noise generated from the power transmission coil400. That is, most of magnetic flux generated from the power transmission coil400interlinks with the power receiving coil600to make an AC current flow in the power receiving coil600. However, a part of magnetic flux generated from the power transmission coil400is radiated to the surroundings as radiation noise without interlinking with the power receiving coil600. Such radiation noise may cause malfunction of surrounding electronic devices and is thus desirably reduced as much as possible. The noise suppressing pattern N is provided for reducing such radiation noise. By disposing the noise suppressing pattern N at a position between the power transmission coil400and the power receiving coil600and near the power transmission coil400, it is possible to shield much radiation noise while maintaining the amount of magnetic flux that interlinks with the power receiving coil600. Further, in the present embodiment, the capacitor electrode patterns63to68are disposed in a distributed manner, so that a sufficient installation space for the noise suppressing pattern N is left on the surface11of the first substrate10, making it possible to enhance noise suppressing effect.

While the preferred embodiment of the present disclosure has been described, the present disclosure is not limited to the above embodiment, and various modifications may be made within the scope of the present disclosure, and all such modifications are included in the present disclosure.

For example, the first coil100, second coil300, and conductive coil400may each constitute a conductor pattern by winding a conductive wire.

Further, the conductor patterns formed on the surfaces11and12of the first substrate10and the surfaces21and22of the second substrate20may be provided thereon through another material layer containing resin.

The technology according to the present disclosure includes the following configuration examples but not limited thereto.

An antenna device according to the present disclosure includes a first coil wound in a plurality of turns and a second coil disposed outside the first coil as viewed in the coil axis direction of the first coil. The first coil is configured such that a first interval between turns in a first direction is larger than a second interval between turns in a second direction perpendicular to the first direction, and the inter-coil distance between the outer edge of the first coil and the inner edge of the second coil is larger than the second interval as viewed in the coil axis direction. With this configuration, there can be achieved an antenna device providing a sufficiently wide coverage area and communication distance.

In the above antenna device, the inter-coil distance may be smaller than the first interval. This allows coupling between the first and second coils to be ensured to some extent and allows communication to be performed through the second coil even when a communication target device is positioned outside the first coil.

In the above antenna device, the first interval may be substantially equal to the width in the first direction of an opening formed by the innermost turn of the first coil. This can prevent the occurrence of a so-called null point.

In the above antenna device, opposite ends of the second coil may be opened. This eliminates the need to connect the second coil to another external circuit.

The antenna device according to the present disclosure may further include a first capacitor electrode pattern connected to one end of the second coil and a second capacitor electrode pattern connected to the other end of the second coil and overlapping the first capacitor electrode pattern. With this configuration, a resonance circuit is formed by the second coil and a capacitor.

The antenna device according to the present disclosure may further include a plurality of first capacitor electrode patterns disposed along the second coil and connected respectively to different positions of the second coil and a second capacitor electrode pattern connected to one end of the second coil and overlapping the plurality of first capacitor electrode patterns. This enhances design freedom. Further, even when the antenna device is used overlapping a power transmission coil for a wireless power transmission device, interference between magnetic flux generated from the power transmission coil and the first and second capacitor electrode patterns is reduced, making it possible to suppress an increase in the AC resistance of the power transmission coil.

In the above antenna device, the plurality of first capacitor electrode patterns may be disposed between the first and second coils. This makes it possible to carry out trimming of the conductor pattern of the second coil easily while preventing breakage thereof. Further, when a communication target device is positioned outside the first coil, coupling between the second coil and the communication target device can be enhanced.

The antenna device according to the present disclosure may further include a magnetic member overlapping the first coil as viewed in the coil axis direction, and the distance between the outer edge of the second coil and the outer edge of the magnetic member may be smaller than the inter-coil distance. This can further extend the antenna coverage area.

The antenna device according to the present disclosure may further include a substrate and a conductor pattern disposed on one main surface of the substrate and including a plurality of linear patterns extending in the second direction and a connection pattern connecting the plurality of linear patterns, and the first and second coils may be disposed on the other main surface of the substrate. This can reduce radiation noise.

A wireless power transmission device according to the present disclosure includes the above-described antenna device and a plurality of power transmission coils disposed in such a way as to overlap the antenna device in the coil axis direction. With the thus configured wireless power transmission device, it is possible to perform not only communication but also wireless power transmission.