JP2008205216A - Laminated coil unit and electronic apparatus having the same, and charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated coil unit capable of increasing a coil Q value by increasing inductance L that is a coil characteristic and decreasing resistance R, to provide an electronic apparatus using the laminated coil unit, and to provide a charger. <P>SOLUTION: The laminated coil unit is used for at least one of primary- and secondary-side coils for contactless power transmission. The unit has N (N is an even number of not less than 4) plane air cores 40A-40D, and each of N plane air cores is composed of a spiral conductive pattern formed on an insulating board and is laminated in the thickness direction of the insulating board. N/2 sets of coil connection units 80, 82, where respective two plane air cores 40A, 40B and 40C, 40D in the N air cores are connected in a first connection form (for example, parallel) that is either parallel or series, are connected in a second connection form (for example, series) that is the other of parallel and series. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated coil unit, an electronic device having the same, and a charger.

  When manufacturing a coil with the pattern of a multilayer board, depending on the connection method between each layer, the buildup board was used and the connection between coils was performed by the blind via (patent documents 1). For this reason, the cost has been increased. When a coil is formed using a rigid substrate and a through hole, the layout of the through hole and the pattern becomes complicated. Furthermore, many through holes must be provided in the center of the coil, leading to deterioration of the coil characteristics.

  Further, as a flat coil, a double spiral coil is formed on the same surface of an insulating substrate to facilitate short circuit inspection (Patent Document 2), or the double spiral coil is formed in different layers, and each layer is formed. There is one in which the coils are connected in series or in parallel (Patent Document 3).

However, in order to increase the inductance L, which is a characteristic required for the coil, to decrease the resistance R, and to increase the Q value of the coil, the setting of the coil conductor width and the number of turns is extremely complicated. It was difficult to design the coil on the street.
JP 2000-208327 A JP-A-10-199727 JP 2001-185419 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a laminated coil unit capable of increasing the inductance L, which is a characteristic required for the coil, and reducing the resistance R, thereby increasing the Q value of the coil, and an electronic device using the same. And providing a charger.

One aspect of the present invention is a laminated coil unit used for at least one of a primary coil and a secondary coil for contactless power transmission,
N (N is an even number of 4 or more) planar air-core coils,
Each of the N planar air-core coils is composed of a spiral conductive pattern formed on an insulating substrate, and is laminated in the thickness direction of the insulating substrate.
(N / 2) sets of coil connection units in which each two of the N planar air-core coils are connected in a first connection configuration that is one of parallel and series are connected in parallel and in the other. It is connected by a certain second connection form.

According to one aspect of the present invention, the N planar air-core coils are overlapped with each other so that the mutual inductance between the coils can be increased. When N = 4 or more, contactless power transmission is achieved. The total inductance required for the In addition, according to the aspect of the present invention, the total inductance can be increased by the amount including the series connection, and the increase in the total resistance R can be suppressed by the amount including the parallel connection. Therefore, the denominator of Q = (L / C) ^1/2 / R of this coil is small, the numerator is large, and Q can be easily increased. In addition, the multilayer coil unit according to one embodiment of the present invention can realize a thin and flat coil.

  In one aspect of the present invention, both ends of the coil of the (N / 2) sets of coil connection units connected in the second connection form to the exposed surface of the insulating substrate located in the outermost layer of the insulating substrates. 1 and 2 can be formed. If it carries out like this, it is not necessary to provide the extraction electrode of the both ends of a coil in another exposed surface, and another exposed surface can be made substantially flat. When this other exposed surface is disposed on the transmission surface for contactless power transmission, the primary and secondary coils can be disposed close to each other, and transmission efficiency is improved.

  In one aspect of the present invention, the first connection form can be in parallel and the second connection form can be in series. In this case, the inner ends of the N planar air-core coils are connected to each other through a first through hole penetrating the insulating substrate. At this time, the first through hole may be provided only at one place in the plane of the insulating substrate. Therefore, it is not necessary to provide an extra conductive pattern in the planar air-core coil, and transmission efficiency is improved.

  Insulating substrate on which the first and second electrode patterns are formed among the (N / 2) sets of coil connection units when the first connection form is parallel and the second connection form is series. The outer ends of the two planar air-core coils constituting a set of coil connection units including the first electrode pattern are connected to each other through a second through hole penetrating the insulating substrate. Can be connected to. In addition, of the (N / 2) sets of coil connection units, each of two planes constituting at least one other set of coil connection units not including an insulating substrate having the first and second electrode patterns. Each outer end of the air core coil can be connected to the second electrode pattern by being connected to each other through a third through hole penetrating the insulating substrate. As described above, the outer ends of the N planar air-core coils can be connected by the second and third through holes at the periphery of the coil.

  In one aspect of the present invention, the first connection form may be in series and the second connection form may be in parallel. In this case, the inner ends of each of the two planar air-core coils constituting each of the (N / 2) sets of coil connection units are connected to each other through a first through hole penetrating the insulating substrate. can do. At this time, the second through holes are arranged at two locations in the plane of the insulating substrate.

  When the first connection form is in series and the second connection form is in parallel, one planar air-core coil formed on the insulating substrate having the first and second electrode patterns and the parallel connection thereto are provided. The other outer ends of the at least one other planar air-core coil can be connected to each other via the second through-hole penetrating the insulating substrate and connected to the first electrode pattern. In addition, each other planar air-core coil connected in series with the one planar air-core coil and each outer end of at least one other planar air-core coil connected in parallel to the planar air-core coil are connected to the insulating substrate. Can be connected to each other through the third through hole penetrating through the second electrode pattern. Also in this case, the outer ends of the N planar air-core coils can be connected by the second and third through holes at the periphery of the coils.

  In one aspect of the present invention, the first through hole can be formed in the insulating substrate at a position avoiding the center of the air core region. In particular, in one aspect of the present invention, coil characteristics are ensured without increasing the conductor width or increasing the number of turns as compared to connecting all N planar air-core coils in series or all in parallel. As a result, the air core region can be secured relatively wide. Since the center portion of the air core region has the highest magnetic line density, the transmission efficiency can be ensured by forming the first through hole at a position where the center portion is desired to be avoided.

  In one aspect of the present invention, the N planar air-core coils are formed on a smaller number of insulating substrates than N, and two planar air-core coils are arranged on both surfaces of at least one insulating substrate. You may form one by one. In this way, the number of insulating substrates to be stacked can be reduced and the thickness can be further reduced. In addition, the first, second, and third through holes may be formed through all the insulating substrates on which the planar air-core coils are formed. In this way, some through holes are dummy, but the manufacturing cost can be reduced.

  In one embodiment of the present invention, the insulating substrate can be a flexible substrate. Thereby, a laminated coil unit can be made thinner.

  In one aspect of the present invention, a magnetic sheet can be laminated on the insulating substrate located in the outermost layer. This further improves the total inductance and the Q value of the coil.

  Another aspect of the present invention defines an electronic device including the above-described laminated coil unit as a secondary coil and receiving contactless power transmission with a primary coil of a charger.

  Here, the insulating substrate on which the first and second electrode patterns are formed can be disposed on the non-transmission surface side opposite to the transmission surface facing the primary coil. In this way, the gap between the primary and secondary coils can be shortened, and the transmission efficiency is increased.

  Still another aspect of the present invention defines a charger that includes the above-described laminated coil unit as a primary coil and transmits contactless power with a secondary side of an electronic device. Also in this case, the insulating substrate on which the first and second electrode patterns are formed is arranged on the non-transmission surface side opposite to the transmission surface facing the secondary coil, thereby improving transmission efficiency. Can be made.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily.

1. 1. First embodiment 1.1. Charging System FIG. 1 is a diagram schematically showing a charger 10 and an electronic device such as a mobile phone 20 in the charger 10. Charging from the charger 10 to the mobile phone 20 is performed between the primary side coil of the coil unit 12 of the charger 10 and the secondary side coil of the coil unit 22 of the mobile phone 20 placed horizontally on the charger 10. It is performed by contactless power transmission using the electromagnetic induction effect that occurs.

1.2. Structure of Laminated Coil Unit FIG. 2 is an exploded perspective view of a laminated coil unit 30 that is thin and suitable for the coil unit 12 or 22 and has a uniform transmission surface. Since the coil unit 12 mounted on the mobile phone 20 is required to be thinner than the battery charger 10, the laminated coil unit 30 shown in FIG. 2 is particularly suitable for the coil unit 12. Here, the transmission surfaces of the coil units 12 and 22 refer to opposing surfaces when the coil units 12 and 22 are arranged to oppose each other as shown in FIG. Electric power is transmitted from the transmission surface in the coil unit 12 of the charger 10, and electric power is transmitted from the transmission surface in the coil unit 22 of the electronic device 20.

  In FIG. 2, there are N (in the first embodiment, N is an even number of 4 or more, for example, N = 4) planar air-core coils 40A, 40B, 40C, and 40D. The four planar air-core coils 40A, 40B, 40C, 40D are formed from, for example, spiral conductive patterns 60A, 60B, 60C, 60D formed on N = 4 insulating substrates 50A, 50B, 50C, 50D. It is configured.

  In this embodiment, N = 4 planar air-core coils 40A, 40B, 40C, and 40D are formed on N = 4 insulating substrates 50A, 50B, and 50C that are stacked in the thickness direction. However, (N−1) = three insulating substrates 50A, 50B, and 50C may be used. In this case, planar air-core coils 40B and 40C may be formed on both surfaces of the central insulating substrate 50B. Thus, by forming the two planar air-core coils 40B and 40C on both surfaces of the insulating substrate 50B, the thickness of the laminated coil unit 30 can be reduced as compared with the case where it is formed on one surface of a separate insulating substrate. It can be formed as thin as one insulating substrate.

  FIG. 3 is a partially enlarged cross-sectional view in which a laminated coil unit 30 is disposed as a secondary coil unit in the casing 24 of the mobile phone 20. However, FIG. 3 is an example in which planar air-core coils 40B and 40C are formed on both surfaces of a central insulating substrate 50B, and (N−1) = 3 insulating substrates are used, unlike FIG. . In FIG. 3, broken lines are lines of magnetic force generated from the primary coil unit 12 of the charger 10 (not shown). In the laminated coil unit 30, the end face that receives power transmission without contact by the magnetic field lines is referred to as a transmission face 70. In the example of FIG. 3, the surface (module surface) on which the conductive pattern 60 </ b> D of the insulating substrate 50 </ b> C is formed becomes the transmission surface 70. In other words, the module surface is flush with the transmission surface 70. In the case of the structure of FIG. 2, the non-pattern surface of the insulating substrate 50 </ b> D is flush with the transmission surface 70.

  In the laminated coil unit 30, the end surface opposite to the transmission surface 70 is referred to as a non-transmission surface 72. In FIG. 3, a magnetic sheet 74 is disposed on the non-transmission surface 72 of the laminated coil unit 30. Although this magnetic sheet 74 is not essential, there is an advantage that a large total inductance of the laminated coil unit 30 can be secured by providing the magnetic sheet 74 as described later. Although not shown, a magnetic shield sheet may be further added to cover the magnetic sheet 74. In particular, when the laminated coil unit 30 is arranged in an electronic device such as the mobile phone 20 as shown in FIG. 3, magnetic flux leakage that causes eddy currents in other metals in the electronic device can be prevented.

  As shown in FIG. 2, the planar air-core coil 40 </ b> A is formed on one surface 52 </ b> A on the non-transmission surface 72 side of the insulating substrate 50 </ b> A located in the outermost layer on the non-transmission surface 72 side among the four insulating substrates 50 </ b> A to 50 </ b> D. A conductive pattern 60A is formed to form

  Furthermore, a first electrode pattern 55A and a second electrode pattern 56A are formed on one surface 52A on the non-transmission surface 72 side of the insulating substrate 50A. The conductive pattern 60A can be covered with insulation except for the first and second electrode patterns 55A and 56A.

  Similarly, planar air-core coils 40B and 40C are formed on the respective one surfaces 52B and 52C of the second and third insulating substrates 50B and 50C. Of the four insulating substrates, the planar air-core coil 40D is formed on one surface 52D of the insulating substrate 50D located in the outermost layer on the transmission surface 70 side.

1.3. Connection form of laminated coil unit (two parallel coils connected in series)
4 shows a connection form of the laminated coil unit 30 shown in FIG. 2, and FIG. 5 is an equivalent circuit diagram thereof. As shown in FIG. 4, the inner ends of the four planar coil units 40A to 40D are commonly connected. Referring to FIG. 2, the first through-holes 57A that penetrate the insulating substrates 50A, 50B, 50C, and 50D, respectively, at the same positions corresponding to the inner ends of the coils of the three insulating substrates 50A, 50B, 50C, and 50D. 57B, 57C, and 57D are formed. The inner ends of the four planar coil units 40A to 40D are connected in common by the conduction of these first through holes 57A, 57B, 57C, and 57D.

  On the other hand, the outer ends of the planar air-core coils 40A and 40B are connected to each other through second through holes 58A and 58B formed in the insulating substrates 50A and 50B. The second through hole 58A is connected to the first electrode pattern 55A through a conductive pattern on the insulating substrate 50A. The second through holes 58C and 58D are also formed in the insulating substrates 50C and 50D at positions corresponding to the second through holes 58A formed in the insulating substrate 50A. Is a dummy through-hole that is not connected, and does not contribute to the connection between the coils. However, by forming the second through-holes 58A, 58B, 58C, and 58D in the same place of the four insulating substrates 50A, 50B, 50C, and 50D, a multilayer laminated substrate with through-holes can be manufactured at low cost.

  On the other hand, the outer ends of the planar air-core coils 40C and 40D are connected to each other through third through holes 59C and 59D formed in the insulating substrates 50C and 50D. The third through hole 59C is connected to the second electrode pattern 56A via the third through holes 59A and 59B formed in the insulating substrates 50A and 50B and the conductive pattern on the insulating substrate 50A. Yes.

  When connected in this way, the laminated coil unit 30 of the first embodiment has two planar air-core coils 40A and 40B out of N = 4 in parallel (in a broad sense, the first is a series or parallel one). 1 connection form) A set of connected coil connection units 80 (see FIGS. 4 and 5) and the other two planar air-core coils 40C and 40D out of N = 4 are arranged in parallel (in a broad sense). First connection form) Another set of connected coil connection units 82 (see FIGS. 4 and 5) is included. That is, the laminated coil unit 30 includes (N / 2) = 2 coil connection units 80 and 82. The two coil connection units 80 and 82 are connected in series (second connection form that is the other of the series and parallel in a broad sense) between the first and second electrode patterns 55A and 56A.

  In the present embodiment, the insulating substrates 50A to 50D are formed of a four-layer flexible printed circuit board (FPC). However, the present invention is not limited to this, and a rigid insulating substrate may be used. However, it is preferable to use FPC in that the laminated coil unit 30 can be formed thin.

1.4. Action and effect of laminated coil unit (1) Coil Q value The first advantage of the laminated coil unit 30 is that the total inductance is increased and the total resistance is kept small. As a result, the coil Q value (Quality factor) is increased. It is a point to improve. Q is a value indicating the characteristics of the coil, and the larger the value, the better.

When the total inductance of the laminated coil unit 30 is L, the total resistance is R, and the capacitance of the circuit connected to the coil is C, Q = (L / C) ^1/2 / R.

  Here, in the laminated coil unit 30, current directions A1 and A2 from the outer ends of the planar air-core coils 40A and 40B toward the inner end, and current directions from the inner ends to the outer ends of the planar air-core coils 40C and 40D. A3 and A4 all match in the counterclockwise direction in FIG. Furthermore, each conductive pattern 60A-60D of the four planar air-core coils 40A-40D can be matched except for the inner end and outer end shapes, thereby increasing the mutual inductance between the coils.

  By the way, as a first comparative example with respect to the laminated coil unit 30, a coil unit (see FIGS. 9 to 11) in which four coils 40A to 40D are connected in series and four coils 40A to 40D as a second comparative example are arranged in parallel. Assume a connected coil unit (a three-layer parallel coil is shown in FIGS. 12 to 14). However, it is assumed that the shapes of the coils constituting these coil units, such as the line width and the number of turns, are the same as those in the first embodiment. Since both the laminated coil unit 30 and the first and second comparative examples are laminated with four coils, mutual inductance can be ensured in addition to the inductance of the coil itself. Compared to the formed double spiral coil, it is preferable in that the total inductance is increased. In particular, as in this embodiment, by setting N = 4, the effect of increasing the mutual inductance due to the lamination is great. Of course, the laminated coil unit 30 can be configured with N being an even number equal to or greater than 4, and the larger the N, the larger the total inductance.

Further, the laminated coil unit 30 has an advantage that Q can be easily increased as compared with the first and second comparative examples. That is, in the first comparative example configured only by series connection, the total inductance L is the maximum among the three, but the resistance R is also the maximum. Therefore, the denominator and numerator of Q = (L / C) ^1/2 / R are large, and it is difficult to increase Q. On the other hand, in the second comparative example configured only by parallel connection, the total inductance L is the minimum among the three, but the resistance R is also the minimum. Therefore, the denominator and numerator of Q = (L / C) ^1/2 / R become small, and it is difficult to increase Q.

On the other hand, the multilayer coil unit 30 according to the present embodiment can increase the total inductance as much as the series connection is included, and can suppress the increase in the total resistance R as much as the parallel connection is included. Therefore, the denominator of Q = (L / C) ^1/2 / R is small and the numerator is large, so that Q can be easily increased. If characteristics equivalent to those of the laminated coil unit 30 according to the present embodiment are ensured, the coil line width and the number of turns in the first and second comparative examples and the combinations thereof are verified by trial and error. Need to design.

(2) Thinning In the laminated coil unit 30 of this embodiment, if the insulating substrates 50A, 50B, 50C, and 50D are formed thin like, for example, FPC, the thickness of each of the conductor patterns 60A to 60D is 0.035 mm. Thinly formed. Therefore, the effect of improving the thickness dimension of the laminated coil unit 30 is considerably large as compared with the case where four layers of coil wires formed in a spiral shape are laminated. As for the reduction in thickness, as shown in FIG. 3, it is more preferable to form N = 4 planar air-core coils on (N−1) = 3 insulating substrates. As the number of N increases, the number of substrates on which the coils can be formed on both surfaces of the substrate can be increased. Therefore, (N−2) or less substrates can be used to manufacture N coils.

  In particular, as shown in FIG. 3, when the laminated coil unit 30 is mounted on an electronic device, the space occupied by the laminated coil unit 30 in the electronic device can be reduced, and the downsizing of the electronic device can be maintained.

(3) Improvement of power transmission efficiency In FIG. 3, the transmission surface 70 of the laminated coil unit 30 can be made substantially flat. This is because the thickness of the conductive pattern 60D protruding on the insulating substrate 50C is 0.035 mm. As shown in FIG. 2, when N = 4 insulating substrates are used, the transmission surface 70 can be a non-patterned surface, and the transmission surface 70 can be flat.

  In addition, since the first and second electrode patterns 55A and 56A and components are not mounted on the transmission surface 70 of the multilayer coil unit 30, the transmission surface 70 of the multilayer coil unit 30 can be maintained flat. In other words, in the present embodiment, since the first and second electrode patterns 55A and 56A are provided on the non-transmission surface 72 of the laminated coil unit 30, soldering and mounting of mounting components are performed only on the non-transmission surface 72 side. Just do it.

  Note that the first and second electrode patterns 55A and 56A shown in FIG. 2 have shapes for soldering the wiring. Instead, when the non-transmission surface 72 of the multilayer coil unit 30 is a component mounting surface, the first and second electrode patterns 55A and 56A have the two electrodes of the multilayer coil unit 30 as component mounting surfaces. What is necessary is just to form as a pattern for making it conductive, and it is not necessary to widen a line width. That is, the first and second electrode patterns 55 </ b> A and 56 </ b> A only need to function as a pattern for extracting the two terminals of the laminated coil unit 30.

  If the transmission surface 70 of the laminated coil unit 30 is substantially flat, the transmission surface 70 can be brought into close contact with the inner wall of the housing 24 of the electronic device 20 as shown in FIG. Thus, the efficiency of non-contact power transmission can be improved by setting the gap between the primary and secondary coils within, for example, several mm.

  As another reason for improving the power transmission efficiency, it is not necessary to form patterns other than the first through holes 57A, 57B, 57C, and 57D in the air core regions of the four planar air core coils 40A to 40D. . Moreover, it is only necessary to provide one first through hole 57A, 57B, 57C, 57D so as to penetrate at the same position on the plane of the four insulating substrates 50A to 50D.

  In other connection forms to be described later, the first through hole cannot be formed so as to penetrate at the same position on the plane of the insulating substrate, and there are a plurality of positions. Therefore, in this embodiment, the conductor pattern area existing in the air core region is minimized. The air core region is a region where the density of magnetic lines of force shown in FIG. 3 is highest, and the adverse effect on the magnetic lines of force due to the presence of the conductor pattern can be minimized.

2. Second embodiment (two series coils are connected in parallel)
6 to 8 show a second embodiment of the present invention. In the laminated coil unit 100 of the second embodiment, two planar air-core coils 110A and 110B out of N = 4 are connected in series (in a broad sense, a first connection form that is either serial or parallel). A set of connected coil connection units 150 (see FIGS. 7 and 8) and other two planar air-core coils 110C and 110D out of N = 4 are connected in series (first connection form in a broad sense). ) And another set of connected coil connection units 152 (see FIGS. 7 and 8). That is, the laminated coil unit 100 includes (N / 2) = 2 coil connection units 150 and 152. The two coil connection units 150 and 152 are connected in parallel (in a broad sense, the second connection form which is the other of the series and the parallel).

  Also in the second embodiment, as shown in FIG. 6, spiral conductive patterns 130A to 130D for forming four planar air-core coils 110A to 110D on N = 4 insulating substrates 120A to 120D are provided. It has been. Instead, (N−1) = three insulating substrates 120A to 120C may be used, and planar air-core coils 110B and 110C may be provided on both surfaces of the central insulating substrate 120B.

  Also in the second embodiment, as shown in FIG. 6, (N / 2) = 2 sets of coil connection units 150 and 152 are formed on the exposed surface of the insulating substrate 120A located at the outermost layer on the non-transmission surface 72 side. First and second electrode patterns 156A and 157A to which both ends of the coil are connected are formed.

  Then, two sets of coil connection units 150 and 152 are connected in parallel as shown in FIG. 8, and both ends of the coil are penetrated at two places for connecting the first and second electrode patterns 156A and 157A. Two first through holes (152A, 152B, 152C, 152D) and (153A, 153B, 153C, 153D) are formed through the four insulating substrates 120A, 120B, 120C, 120D. As shown in FIG. 7, the inner ends of the planar air-core coils 110A and 110B are connected to each other through through holes 152A and 152B, and the other through holes 152C and 152D are dummy through holes. The inner ends of the planar air-core coils 110C and 110D are connected to each other through through holes 153C and 153D, and the other through holes 153A and 153B are dummy through holes.

  Further, the outer ends of one planar air core coil 110A formed on the insulating substrate 120A having the first and second electrode patterns 156A and 157A and the other planar air core coil 110C connected in parallel thereto are connected. In order to do so, second through holes (154A, 154B, 154C, 154D) penetrating the four insulating substrates 120A to 120D are provided. Here, the outer ends of the planar air-core coils 110A and 110C are connected to the first electrode pattern 156A via the through holes 154A, 154B and 154C. The other through hole 154D is a dummy through hole.

  Third through holes (155A, 155B, 155C) that penetrate the four insulating substrates 120A to 120D to connect the outer ends of the planar air-core coil 110B and the planar air-core coil 110D connected in parallel thereto. , 155D). Note that the outer ends of the planar air-core coils 110B and 110D are connected to the second electrode pattern 157A via through holes 155A to 155D.

  Here, as shown in FIG. 6, in the laminated coil unit 100, the current directions B1 and B3 from the outer end to the inner end of the planar air-core coils 110A and 110C and the inner ends of the planar air-core coils 110B and 110D. Current directions B2 and B4 from the outer edge to the outer edge all coincide in the counterclockwise direction in FIG. Furthermore, the conductive patterns 130A to 130D of the four planar air-core coils 110A to 110D can be matched except for the inner end and outer end shapes, thereby increasing the mutual inductance between the coils.

  Also in the second embodiment, since the four planar air-core coils are connected in series and in parallel as in the first embodiment, the coil characteristics Q are the same as in the first embodiment, and the coil The characteristic Q can be improved. Further, the laminated coil unit 100 can be reduced in thickness as in the first embodiment. In terms of transmission efficiency, the same effect as the first embodiment can be obtained in that the transmission surface can be made flat. However, in the second embodiment, the first through holes (152A, 152B, 152C, 152D) and (153A, 153B, 153C, 153D) for connecting the inner ends of the coils are required in two places. In that respect, the number of through holes in the air core region increases. However, the adverse effect on the magnetic flux can be reduced by setting the first through-holes formed at two locations at positions shifted from the center of the air core region.

3. Comparative Example 1
9 to 11 show the first comparative example. The laminated coil unit 200 according to Comparative Example 1 includes a set of coil connection units 250 (see FIG. 11) in which two planar air-core coils 210A and 210B out of N = 4 are connected in series, and N = It includes another set of coil connection units 252 (see FIG. 11) in which two other planar air-core coils 210C and 210D out of the four are connected in series. By connecting the two coil connection units 250 and 252 in series, four planar air-core coils 210A to 210D are connected in series.

  Also in this comparative example 1, as shown in FIG. 9, spiral conductive patterns 230A to 230D for forming four planar air-core coils 210A to 210D are provided on N = 4 insulating substrates 220A to 220D. Yes. Instead, (N−1) = three insulating substrates 220A to 220C may be used, and planar air-core coils 210B and 210C may be provided on both surfaces of the central insulating substrate 220B.

  Also in this comparative example 1, as shown in FIG. 9, (N / 2) = 2 sets of coil connection units 250 and 252 are formed on the exposed surface of the insulating substrate 220A located at the outermost layer on the non-transmission surface 72 side. First and second electrode patterns 256A and 257A to which both ends are connected are formed.

  Then, two sets of coil connection units 250 and 252 are connected in parallel as shown in FIG. 11, and both ends of the coil are penetrated at two places for connecting the first and second electrode patterns 256A and 257A. Two first through holes (252A, 252B, 252C, 252D) and (253A, 253B, 253C, 253D) are formed through the four insulating substrates 220A, 220B220C, 220D. As shown in FIG. 10, the inner ends of the planar air-core coils 210A and 210B are connected to each other through through holes 252A and 252B, and the other through holes 252C and 252D are dummy through holes. The inner ends of the planar air-core coils 210C and 210D are connected to each other through through holes 253C and 253D, and the other through holes 253A and 253B are dummy through holes.

  Further, in order to connect the outer ends of the planar air-core coil 210B and the planar air-core coil 210C, second through holes (254A, 254B, 254C, 254D) that penetrate the four insulating substrates 220A to 220D are used. Is provided. Here, the outer ends of the planar air-core coils 210B and 210C are connected to each other through through holes 254B and 254C, and the other through holes 254A and 254D are dummy through holes.

  In order to connect the outer end of the planar air-core coil 210D to the second electrode pattern 257A, third through holes (255A, 255B, 255C, 255D) are provided.

  Here, as shown in FIG. 9, in the laminated coil unit 200, the current directions C1 and C3 from the outer ends of the planar air-core coils 210A and 210C toward the inner ends, and the inner ends of the planar air-core coils 210B and 210D. Current directions C2 and C4 from the outer edge to the outer edge all coincide in the counterclockwise direction in FIG. Furthermore, the conductive patterns 230A to 230D of the four planar air-core coils 210A to 210D can be matched except for the inner end and outer end shapes, thereby increasing the mutual inductance between the coils.

  However, in the first comparative example, unlike the first and second embodiments, since all four planar air-core coils are connected in series, both the inductance L and the resistance R are increased, and the Q value of the coil is improved. Not. However, the laminated coil unit 200 can be made thin as in the first and second embodiments. In terms of transmission efficiency, the same effect as in the first and second embodiments can be obtained in that the transmission surface can be made flat. However, in the first comparative example, as in the second embodiment, the first through holes (252A, 252B, 252C, 252D) and (253A, 253B, 253C, 253D) for connecting the inner ends of the coils are 2 The number of through-holes increases in the air core region in that it is required for the location. However, the adverse effect on the magnetic flux can be reduced by setting the first through-holes formed at two locations at positions shifted from the center of the air core region.

4). Comparative Example 2
12 to 14 show the second comparative example. The laminated coil unit 300 according to the comparative example 2 is obtained by connecting three planar air-core coils 310A, 310B, and 310C in parallel.

  In Comparative Example 2, as shown in FIG. 12, spiral conductive patterns 330A to 330C for forming three planar air-core coils 310A to 310C are provided on three insulating substrates 320A to 320C. One insulating substrate 320D is used as a wiring-dedicated pattern. Instead of this, three insulating substrates 320A to 320C may be used, planar air-core coils 210B and 210C may be provided on both surfaces of the central insulating substrate 220B, and the insulating substrate 320C may be used as a wiring-dedicated substrate.

  Also in this comparative example 2, as shown in FIG. 12, the coil ends of three planar air-core coils 310A to 310C connected in parallel to the exposed surface of the insulating substrate 320A located in the outermost layer on the non-transmission surface 72 side. First and second electrode patterns 356A and 357A to which the portions are connected are formed.

  The first planar through holes (352A, 352B, 352A, 352B, and 352A are connected in parallel to the three planar air-core coils 310A to 310C and both ends of the coils are connected to the first and second electrode patterns 356A and 357A. 352C, 352D) are formed through the four insulating substrates 320A, 20B320C, 20D. As shown in FIG. 13, the inner ends of the three planar air-core coils 310A to 310C are connected to each other through through holes 352A, 352BC, 352C, and are formed in the other through hole 352D and the insulating substrate 320D. The wiring pattern 353D is connected to a through hole 355D described later.

  The outer ends of the three planar air-core coils 310A to 310C are connected to each other through second through holes (354A, 354B, 354C, and 354D) that penetrate the four insulating substrates 320A to 320D. Yes. Here, the through hole 354D is a dummy through hole.

  In order to connect the inner end of the planar air-core coil 210C to the second electrode pattern 357A, third through holes (355A, 355B, 355C, 355D) are provided. The through hole 355D formed in the insulating substrate 320D is connected to the inner end of the planar air-core coil 310C via the wiring pattern 353D and through holes 352C and 352D formed in the insulating substrate 320D.

  Here, as shown in FIG. 12, in the laminated coil unit 300, the current directions D1 to D3 from the outer end to the inner end of the planar air-core coils 310A to 310C all coincide in the counterclockwise direction in FIG. To do. Furthermore, the conductive patterns 330A to 330C of the three planar air-core coils 310A to 310C can be matched except for the inner end and outer end shapes, thereby increasing the mutual inductance between the coils.

  In the second comparative example, unlike the first and second embodiments, all three planar air-core coils are connected in parallel, so that both the inductance L and the resistance R are reduced, and the Q value of the coil is not improved. In terms of the reduction in thickness, it is inferior to the first and second embodiments and the comparative example 1 because a wiring dedicated substrate for forming the wiring pattern 353D is required. In terms of transmission efficiency, the same effects as those of the first and second embodiments and Comparative Example 1 can be obtained in that the transmission surface can be made flat. Further, in Comparative Example 2, as in the first embodiment, the first through holes (352A, 352B, 352C, 352D) for connecting the inner ends of the coils may be formed through one place, There is no increase in the number of through holes in the air core region.

5. FIG. 15 shows measured values of total inductance L, total resistance R, and characteristic Q measured with various coil shapes for the first embodiment and the first and second comparative examples. . NO. 1-NO. 9 is Comparative Example 2 and NO. 10-NO. 18 compares Comparative Example 1 with NO. 19-NO. Reference numeral 24 denotes the first embodiment.

  As common conditions, the gap between the outer shape of the coil and the pattern was made constant, and the conductor thickness (pattern thickness) was set to 0.035 mm, for example. The changing conditions are the conductor width (pattern width), the number of turns on one side, the connection form (first embodiment, first and second comparative examples), and the presence or absence of the magnetic sheet 74 (see FIG. 2). The conductor thickness is not limited to 0.0035 mm, and other numerical values can be used.

  From FIG. 15, it can be seen that the provision of the magnetic sheet 74 increases the total inductance and improves the Q value of the coil.

  For the reasons described above, the NO. 19-NO. 24, the Q value of the coil is improved even if the conductor width W and the number of turns on one side are not changed as much as in the first and second comparative examples.

  In addition, although it has not measured about 2nd Embodiment, it can anticipate that the substantially same result as 1st Embodiment will be obtained.

  Although the present embodiment has been described in detail as described above, those skilled in the art can easily understand that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings.

  Although the present embodiment relates to contactless power transmission, it can be similarly applied to contactless signal transmission using the electromagnetic induction principle.

  This embodiment can be applied to all electronic devices that perform power transmission and signal transmission. For example, wristwatches, electric toothbrushes, electric shaving, cordless phones, personal handyphones, mobile personal computers, PDAs (Personal Digital Assistants) It can be applied to a to-be-charged device and a charging device including a secondary battery such as an electric bicycle.

It is a perspective view which shows an example of the charger and electronic device which concern on this invention. It is a disassembled perspective view of the laminated coil unit which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the state which attached the laminated coil unit which concerns on this invention to the electronic device. It is a figure which shows typically the connection state of the laminated coil unit shown in FIG. FIG. 3 is an equivalent circuit diagram of the multilayer coil unit shown in FIG. 2. It is a disassembled perspective view of the laminated coil unit which concerns on the 2nd Embodiment of this invention. It is a figure which shows typically the connection state of the laminated coil unit shown in FIG. FIG. 7 is an equivalent circuit diagram of the multilayer coil unit shown in FIG. 6. It is a disassembled perspective view of the laminated coil unit which concerns on the comparison row | line 1 of this invention. It is a figure which shows typically the connection state of the laminated coil unit shown in FIG. FIG. 10 is an equivalent circuit diagram of the multilayer coil unit shown in FIG. 9. It is a disassembled perspective view of the laminated coil unit which concerns on the comparison row | line 2 of this invention. It is a figure which shows typically the connection state of the laminated coil unit shown in FIG. FIG. 12 is an equivalent circuit diagram of the multilayer coil unit shown in FIG. 11. It is a characteristic view of the laminated coil unit manufactured according to the 1st Embodiment of this invention, the comparative example 1, and the comparative example 2. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Charger, 12 Coil unit, 20 Electronic device, 22 Coil unit, 24 Case, 30, 100, 200,300 Laminated coil unit, 40A-40D, 110A-110D, 210A-210D, 310A-310C Planar air core Coil, 50A-50B, 120A-120D, 220A-220D, 320A-320D Insulating substrate, 60A-60D, 130A-130D, 230A-230D, 330A-330C Conductive pattern, 55A, 156A, 256A, 356A First electrode pattern 56A, 157A, 257A, 357A second electrode pattern, 57A-57D, 152A-152D, 153A-153D, 252A-252D, 253A-253D first through hole, 58A-58D, 154A-154D, 54A~254D second through hole, 59A~59D, 155A~155D, 255A~255D third through-hole, 80,150 first coil unit, 82,152 second coil unit

Claims (18)

A laminated coil unit used for at least one of a primary coil and a secondary coil for contactless power transmission,
N (N is an even number of 4 or more) planar air-core coils,
Each of the N planar air-core coils is composed of a spiral conductive pattern formed on an insulating substrate, and is laminated in the thickness direction of the insulating substrate.
(N / 2) sets of coil connection units in which each two of the N planar air-core coils are connected in a first connection configuration that is one of parallel and series are connected in parallel and in the other. A laminated coil unit connected in a second connection form. In claim 1,
First and second ends of the coil connecting units connected in the second connection form are connected to the exposed surface of the insulating substrate located at the outermost layer of the insulating substrates. A laminated coil unit, wherein a second electrode pattern is formed. In claim 2,
The first connection form is parallel and the second connection form is series;
The inner ends of the N planar air-core coils are connected to each other through a first through hole penetrating the insulating substrate. In claim 3,
Of each of the (N / 2) sets of coil connection units, each of two planar air-core coils constituting one set of coil connection units including an insulating substrate on which the first and second electrode patterns are formed. The outer end is connected to each other via a second through hole penetrating the insulating substrate and connected to the first electrode pattern. In claim 4,
Of the (N / 2) sets of coil connection units, each of two planar air cores constituting at least one other set of coil connection units not including an insulating substrate having the first and second electrode patterns Each outer end of the coil is connected to each other through a third through hole penetrating the insulating substrate, and is connected to the second electrode pattern. In claim 2,
The first connection form is in series and the second connection form is in parallel;
The inner ends of each of the two planar air-core coils constituting each of the (N / 2) sets of coil connection units are connected to each other via a first through hole that penetrates the insulating substrate. A laminated coil unit characterized by that. In claim 6,
Each outer end of one planar air-core coil formed on the insulating substrate having the first and second electrode patterns and at least one other planar air-core coil connected in parallel to the planar air-core coil is connected to the insulating substrate. The multilayer coil unit is connected to the first electrode pattern by being connected to each other through a penetrating second through hole. In claim 7,
Each other end of the other planar air-core coil connected in series with the one planar air-core coil and at least one other planar air-core coil connected in parallel therewith penetrates the insulating substrate. A laminated coil unit, being connected to each other through a third through hole and connected to the second electrode pattern. In any of claims 3 to 8,
The multilayer coil unit, wherein the first through hole is formed in the insulating substrate at a position avoiding a center of the air core region. In any one of Claims 1 thru | or 9,
The multilayer coil unit, wherein the N planar air-core coils are respectively formed on N insulating substrates. In any one of Claims 1 thru | or 9,
The N planar air-core coils are formed on a smaller number of insulating substrates than N, and two planar air-core coils are formed on both surfaces of at least one insulating substrate. A laminated coil unit characterized by In claim 4 or 8,
The first, second and third through holes are formed so as to penetrate all the insulating substrates on which the N planar air-core coils are formed. In any one of Claims 1 to 12,
The laminated coil unit, wherein the insulating substrate is a flexible substrate. In any one of Claims 1 thru | or 13.
A laminated coil unit, wherein a magnetic sheet is laminated on an insulating substrate located in the outermost layer.   An electronic apparatus comprising: the laminated coil unit according to any one of claims 1 to 14 as a secondary coil, and receiving contactless power transmission with a primary coil of a charger.     An electronic device comprising the laminated coil unit according to any one of claims 2 to 9 as a secondary side coil and receiving contactless power transmission with a primary side coil of a charger, wherein the first and second The electronic device in which the electrode pattern is formed is disposed on a non-transmission surface side opposite to the transmission surface facing the primary coil.   15. A battery charger comprising: the laminated coil unit according to claim 1 as a primary coil, and performing contactless power transmission with a secondary side of an electronic device.     A charger that includes the laminated coil unit according to any one of claims 2 to 9 as a primary side coil and transmits contactless power to a secondary side coil of an electronic device, wherein the first and second The charger, wherein the insulating substrate on which the electrode pattern is formed is disposed on the non-transmission surface side opposite to the transmission surface facing the secondary coil.

Images