JP5988146B2 - Transmission coil and portable radio terminal - Google Patents

Description

  The present invention relates to a transmission coil capable of contactless power transmission and contactless wireless communication, and a portable wireless terminal equipped with the transmission coil.

  For example, portable wireless terminals such as a mobile phone terminal or a smartphone are widely used which are equipped with NFC (Near Field Communication) including FeliCa (registered trademark), that is, non-contact wireless communication (for example, RFID (Radio Frequency IDentification)) function. ing. With this type of contactless wireless communication, an electronic money function, an electronic ticket function, and the like are realized.

  In recent years, portable wireless terminals equipped with a function of charging a battery (contactless charging) by transmitting power in a contactless manner are being used. As a non-contact power transmission method, there are an electromagnetic induction method or a magnetic field resonance method, and a method that performs power transmission by arranging a power supply side coil and a power reception side coil facing each other is the mainstream.

  In portable wireless terminals equipped with a non-contact charging function, those in which a charging coil is integrated with a battery pack are mainly used. For this reason, when it is going to make a battery pack still thinner for thickness reduction of a portable radio terminal, there is a subject that battery capacity decreases. On the other hand, when the charging coil is configured separately from the battery pack, in the portable wireless terminal equipped with the above non-contact wireless communication function, it becomes a problem to coexist the non-contact wireless communication coil and the charging coil. .

  Assume a case where a non-contact wireless communication coil and a non-contact power transmission coil (charging coil) coexist. As a conventional example in which two coils are provided, for example, in Patent Document 1, a first coil that forms a power wave antenna and a second coil that forms a data wave antenna form a double ring. A wireless card arranged in the above is disclosed. With this configuration, there is little possibility that the first coil and the second coil are covered with fingers of a hand holding the wireless card, and the reception status of both coils can be made substantially the same.

JP 2004-110854 A

  In the configuration of Patent Document 1 described above, the two coils are arranged so as to form a double ring, so that the arrangement area of the coils increases. In addition, if a plurality of coils are simply provided without considering the performance of each coil, performance degradation is expected due to electromagnetic coupling between the coils. In particular, when a plurality of coils are arranged close to each other in order to reduce the size of a terminal on which a coil is mounted, performance such as power transmission efficiency and communication distance deteriorates due to electromagnetic coupling between the coils.

  In addition, the above Patent Document 1 does not mention simplification of the manufacturing process of the wireless card when two coils are used. Mobile wireless terminals including the above-described contactless charging function and contactless wireless communication function are likely to be widely used in the future. When mass-producing such portable wireless terminals, the performance deterioration of the two coils is suppressed and simplified. It is considered that the arrangement of each coil so that it can be manufactured is required.

  The present invention has been made in view of the above-described conventional circumstances. When a plurality of coils such as a non-contact wireless communication coil and a non-contact power transmission coil coexist, the deterioration of the performance of each coil is suppressed. An object of the present invention is to provide a transmission coil and a portable wireless terminal that can be easily manufactured in a space-saving manner.

The present invention is a transmission coil, a first coil that receives power using non-contact power transmission, a second coil used for wireless communication, a first magnetic body having a predetermined magnetic permeability, A second magnetic body having a permeability different from a predetermined permeability of the one magnetic body, the first coil is disposed on the surface of the first magnetic body, and the second magnetic body is disposed on the surface of the first magnetic body. The second magnetic body is disposed outside the first coil, and the second coil is disposed on the surface of the second magnetic body.

  With the above configuration, when a plurality of coils coexist, electromagnetic coupling between the coils can be reduced, and performance degradation due to electromagnetic coupling is suppressed. Further, by arranging a plurality of coils close to each other, the arrangement area can be reduced, and a coil with little performance deterioration can be easily manufactured in a small space.

  Further, the present invention includes the transmission coil described above, wherein the magnetic permeability of the first magnetic body is higher than the magnetic permeability of the second magnetic body.

  Further, the present invention includes the transmission coil described above, wherein the resonance frequency of the first coil is lower than the resonance frequency of the second coil.

  Moreover, this invention is said transmission coil, Comprising: The guide part which guides so that the distance of a said 1st coil and a said 2nd coil may become more than predetermined | prescribed space | interval is further provided.

  Moreover, this invention is said transmission coil, Comprising: The said guide part is formed in the peripheral part by the side of the said 1st coil of a said 2nd magnetic body.

  The present invention further includes a transmission coil as described above, wherein the transmission coil is further disposed on the outside of the first coil, and the second coil is formed as a predetermined metal pattern. And formed on the peripheral edge of the substrate on the first coil side.

  Further, the present invention is a portable wireless terminal equipped with any one of the above transmission coils.

  According to the present invention, when a plurality of coils such as a non-contact wireless communication coil and a non-contact power transmission coil coexist, it is possible to easily manufacture in a space-saving manner while suppressing performance deterioration of each coil. Can do.

The top view which shows the structure of the coil unit which concerns on 1st Embodiment. 1A is a cross-sectional view of the coil unit according to the first embodiment, FIG. 1A is a cross-sectional view taken along the line AA ′ in FIG. 1, and FIG. (A) The figure which shows the magnetic field distribution of the coil unit at the time of the operation | movement of a 1st coil in the position (position of FIG. 2 (A)) of the AA 'line cross section of FIG. 1, (B) AA of FIG. 'The figure which shows the magnetic field distribution of the coil unit at the time of operation | movement of a 2nd coil in the position (position of FIG. 2 (A)) of a line cross section. (A) The figure which shows the magnetic field distribution of the coil unit at the time of the operation | movement of a 1st coil in the position (position of FIG. 2 (B)) of the BB 'line cross section of FIG. 1, (B) BB of FIG. The figure which shows magnetic field distribution of the coil unit at the time of operation | movement of a 2nd coil in the position (position of FIG. 2 (B)) of line '. 1 is a block diagram showing a configuration of a portable wireless terminal equipped with a coil unit of the present embodiment, a charger as an external device, and a reader / writer device. (A), (B) The figure which shows an example of the dimension of the coil unit which concerns on an Example, (C) The top view of the coil unit which concerns on an Example, (D) The cross section in the AA 'line of FIG.6 (C) Figure (A) The figure which shows the result of having measured the power transmission efficiency at the time of non-contact power transmission as performance of the coil unit which concerns on an Example, (B) The maximum at the time of non-contact wireless communication as performance of the coil unit which concerns on an Example The figure which shows the result of measuring the communication distance (A), (B) The figure which shows an example of the dimension of the coil unit which concerns on a comparative example, (C) The top view of the coil unit which concerns on a comparative example, (D) The cross section in the AA 'line of FIG.8 (C) Figure (A) The figure which shows the result of having measured the power transmission efficiency at the time of non-contact power transmission as performance of the coil unit which concerns on a comparative example, (B) The maximum at the time of non-contact wireless communication as performance of the coil unit which concerns on a comparative example The figure which shows the result of measuring the communication distance The top view which shows the structure of the coil unit which concerns on 2nd Embodiment. (A) Cross-sectional view taken along line AA 'in FIG. 10, (B) Cross-sectional view taken along line BB' in FIG. The figure explaining the space | interval between the 1st coil 12 and the 2nd coil 22, (A) The top view which shows the structure of a coil unit, (B) The arrangement | positioning space | interval between the 1st coil 12 and the 2nd coil 22 12C is an enlarged view of the region g in FIG. 12A, and FIG. 12C is an enlarged view of the region g in FIG. 12A when the arrangement interval between the first coil 12 and the second coil 22 is not appropriate. Figure (A) Table showing measurement results under conditions a and b, (B) Graph showing measurement results under conditions a and b (A)-(C) Sectional drawing explaining the flow of an assembly of a coil unit The figure which shows the structure of the coil unit which concerns on Example 1 at the time of making the 2nd magnetic body 21B serve as the guide member 21g, (A) and (B) The figure which shows an example of the dimension of the coil unit which concerns on Example 1. (C) The top view of the coil unit which concerns on Example 1, (D) Sectional drawing in the AA 'line of FIG.15 (C) The figure which shows the structure of the coil unit which concerns on Example 2 at the time of using both the 2nd magnetic body 21B and the board | substrate 30C as guide members 21g and 30g, respectively, (A) And (B) The coil which concerns on Example 2 The figure which shows an example of the dimension of a unit, (C) The top view of the coil unit which concerns on Example 2, (D) Sectional drawing in the AA 'line of FIG.16 (C) The figure which shows the structure of the coil unit which concerns on the comparative example at the time of not providing the guide member, (A) And (B) The figure which shows an example of the dimension of the coil unit which concerns on a comparative example, (C) The coil unit which concerns on a comparative example (D) Sectional view taken along the line AA 'in FIG. 17 (C) The figure which shows the measurement result of the performance of the coil unit which concerns on Example 1 and 2, (A) Power transmission efficiency at the time of non-contact power transmission, (B) Maximum communication distance at the time of non-contact wireless communication (A)-(C) The figure which shows an example of the shape of various guide members (D)-(F) The figure which shows another example of the shape of various guide members following FIG.

  In the following embodiments, as an example of the transmission coil according to the present invention and a portable wireless terminal equipped with the transmission coil, a coil unit as a transmission coil having a non-contact wireless communication coil and a non-contact power transmission coil, The structural example of the portable radio | wireless terminal carrying a coil unit is shown.

(First embodiment)
FIG. 1 is a plan view showing the configuration of the coil unit according to the first embodiment. FIG. 2 is a cross-sectional view of the coil unit according to the first embodiment. 2A is a cross-sectional view taken along the line AA ′ of FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG. The direction of arrow H in FIG. 2A represents the direction on the inner wall side of the rear casing of the portable wireless terminal in which the coil unit of this embodiment is mounted, and the direction opposite to arrow H in FIG. This represents the direction inside the housing of the wireless terminal, that is, the direction of the front casing.

  The coil unit of this embodiment includes a first magnetic body 11 having a predetermined magnetic permeability, a first coil 12 functioning as a non-contact power transmission coil, and a magnetic permeability different from the predetermined magnetic permeability of the first magnetic body 11. And a second coil 22 functioning as a non-contact wireless communication coil. In the coil unit of the present embodiment, the first magnetic body 11 is provided corresponding to the first coil 12, and the second magnetic body 21 is provided corresponding to the second coil 22.

  The first magnetic body 11 is formed in a rectangular plate shape, the first coil 12 is disposed on one surface of the plate surface (the inner wall side of the back casing of the portable wireless terminal), and the other plate surface (the portable wireless terminal). A battery pack, a shield case (not shown), or the like is disposed on the surface of the inside of the housing. The first magnetic body 11 is configured using a material having a magnetic permeability higher than 1, such as ferrite. As the relative permeability μr1 of the first magnetic body 11, for example, μr1 = 200 to 2000 is used.

  The first coil 12 is configured using a coil in which a conductor winding is wound in an elliptical ring shape, and receives power supplied (transmitted) from an external charger as a charging coil. The resonance frequency f1 of the first coil 12 is a frequency adjusted using a capacitor or the like connected in parallel or in series with the first coil 12, and is, for example, about f1≈100 kHz.

  The second magnetic body 21 is formed in a rectangular annular plate shape, and one of the plate surfaces (inside the casing of the portable wireless terminal) is one of the plate surfaces of the first magnetic body 11 (inner wall of the rear casing of the portable wireless terminal). It is arranged so as to abut on the surface of the side. Further, the second magnetic body 21 is placed on the other side of the plate surface (the inner wall side of the rear housing of the portable wireless terminal) on the opposite side of the arrow 30 in FIG. A second coil 22 mounted on the inside of the housing is disposed. Furthermore, the entire surface of the second magnetic body 21 is disposed outside the outer peripheral portion of the first coil 12, and the outer diameter of the second magnetic body 21 and the outer diameter of the first magnetic body 11 are substantially the same. is there. The second magnetic body 21 is configured using a material having a magnetic permeability higher than 1, such as ferrite. As the relative permeability μr2 of the second magnetic body 21, for example, μr2 = 10 to 300 is used.

  The second coil 22 is wound in a square ring shape by a conductor wiring pattern formed on the surface of the substrate 30 on the side opposite to the arrow H in FIG. 2A (inside the casing of the portable wireless terminal). It is comprised using the coil which consists of. The second coil 22 is a non-contact wireless communication coil and transmits / receives data to / from an external device such as a reader / writer device. The resonance frequency f2 of the second coil 22 is a frequency adjusted using a capacitor or the like connected in parallel or in series with the second coil 22, and is, for example, about f2≈13.56 MHz.

  The substrate 30 is formed using, for example, glass epoxy resin, and a rear housing of a portable wireless terminal formed of, for example, ABS (Acrylonitrile Butadiene Styrene) resin on the surface in the direction of arrow H in FIG. Be placed. A pair of first terminals 31 for the first coil 12 and a pair of second terminals 32 for the second coil 22 are formed at one end of the substrate 30 by a conductor wiring pattern. The first terminal 31 is connected to the first coil 12 through a wiring pattern, and the second terminal 32 is connected to the second coil 22 through the wiring pattern of the substrate 30. 2A and 2B, the wiring patterns from the first terminal 31 and the second terminal 32 to the first coil 12 and the second coil 22 are shown in order to avoid complication of the drawing. Is omitted.

  The coil unit according to the present embodiment includes a first magnetic body in the thickness direction of the coil (vertical direction in FIG. 2) from the lower side of FIG. 2 to the arrow H direction (the direction of the inner wall side of the back casing of the portable wireless terminal) 11. The first coil 12 and the second magnetic body 21 are laminated on the surface of the first magnetic body 11. In addition, on the surface of the second magnetic body 21, in the thickness direction of the coil, the second coil 22 and the substrate are arranged in the arrow H direction (the direction of the inner wall side of the back casing of the portable wireless terminal) from the lower side of FIG. Laminated in the order of 30. When the coil unit according to the present embodiment is mounted on a portable radio terminal, the rear casing of the portable radio terminal is positioned in the direction of arrow H further than the second coil 22 and the coil unit is housed and provided in the casing. Therefore, when viewed from the external device side, that is, the inner wall side of the back casing of the portable wireless terminal, the substrate 30, the second coil 22, the second magnetic body 21, the first coil 12, and the first magnetic body 11 are laminated in this order. Be placed. By arranging the coils close to each other in such a configuration in which a plurality of magnetic bodies are stacked on the coil, performance deterioration due to electromagnetic coupling of both coils can be suppressed, and the coil layout area can be reduced while ensuring the performance of each coil. The size can be reduced and the size can be reduced.

  At this time, it is preferable that the 1st coil 12 and the 2nd coil 22 are arrange | positioned so that it may not overlap in the thickness direction of a coil. In addition, since the first coil 12 has an oval shape and the second coil 22 has a rectangular shape, the four coil portions of the second coil 22 are non-overlapping regions. Located on the outside. With such a configuration, electromagnetic coupling between both coils can be reduced.

  In this embodiment, the relationship between the resonance frequencies of the first coil 12 and the second coil 22 is such that the resonance frequency of the first coil 12 is lower than the resonance frequency of the second coil 22 (f1 <f2). The relationship between the magnetic permeability of the first magnetic body 11 and the second magnetic body 21 is such that the permeability of the first magnetic body 11 is higher than the permeability of the second magnetic body 21 (relative magnetic permeability μr1> μr2). Is preferable. By setting the characteristics of the first coil 12, the second coil 22, the first magnetic body 11, and the second magnetic body 21 as described above, it is possible to more effectively reduce performance degradation due to electromagnetic coupling between the two coils.

  Next, the operation during operation of the coil unit of the present embodiment will be described. FIG. 3A is a diagram showing the magnetic field distribution of the coil unit at the time of operation of the first coil 12 at the position of the cross section along line AA ′ of FIG. 1 (position of FIG. 2A). FIG. 3B is a diagram showing the magnetic field distribution of the coil unit at the time of the operation of the second coil 22 at the position of the cross section along line AA ′ of FIG. 1 (position of FIG. 2A). 4A is a diagram showing the magnetic field distribution of the coil unit at the time of the operation of the first coil 12 at the position of the cross section along the line BB ′ of FIG. 1 (position of FIG. 2B). FIG. 4B is a diagram showing the magnetic field distribution of the coil unit at the time of the operation of the second coil 22 at the position of the cross section along line BB ′ of FIG. 1 (position of FIG. 2B).

  During operation of the first coil 12, that is, during power transmission, as shown in FIGS. 3A and 4A, the magnetic lines of force pass through the first magnetic body 11 in the vicinity of the first coil 12. A magnetic field is generated so as to enter the space. In this case, the influence of the magnetic field from the first coil 12 to the second coil 22 is small.

  Further, when the second coil 22 is operated, that is, during data transmission of non-contact wireless communication, as shown in FIGS. 3 (B) and 4 (B), the magnetic lines of force are generated near the second coil 22 in the second magnetic body. A magnetic field is generated so as to pass through 21 and exit into space. In this case, the influence of the magnetic field from the second coil 22 to the first coil 12 is small.

  Since the coil unit of the present embodiment has a region where the first coil 12 and the second coil 22 do not overlap, electromagnetic coupling between the coils is reduced. In particular, electromagnetic coupling can be made sufficiently small in the four corner regions of the coil where the coils do not overlap as shown in FIGS. 4 (A) and 4 (B).

  FIG. 5 is a block diagram showing a configuration of a portable wireless terminal equipped with the coil unit of the present embodiment, a charger as an external device, and a reader / writer device.

  The portable wireless terminal 50 includes a first coil 12 for charging and a second coil 22 for non-contact wireless communication. The first coil 12 is connected to the contactless charging unit 51, and the second coil 22 is connected to the contactless wireless communication unit 52. The first coil 12 is connected in parallel with the capacitor 54, and further connected to the rectifier circuit 55 of the non-contact charging unit 51. The second coil 22 is connected in parallel with the capacitor 56 and further connected to the modulation / demodulation circuit 57 of the non-contact wireless communication unit 52. The non-contact charging unit 51 and the non-contact wireless communication unit 52 are connected to a control circuit 53, and the operation of each unit is controlled by the control circuit 53.

  The charger 60 includes a non-contact power transmission coil 63. The non-contact power transmission coil 63 is connected in parallel with the capacitor 64 and further connected to the AC power supply circuit 61. The AC power supply circuit 61 is connected to the control circuit 62, and the output of AC power for charging is controlled by the control circuit 62.

  The reader / writer device 70 includes a non-contact wireless communication coil 73. The non-contact wireless communication coil 73 is connected in parallel with the capacitor 74 and further connected to the modulation / demodulation circuit 71. The modulation / demodulation circuit 71 is connected to the control circuit 72, and the control circuit 72 controls the data modulation and demodulation operations by non-contact wireless communication.

  In the above configuration, when charging the portable wireless terminal 50, the non-contact power transmission coil 63 of the charger 60 and the first coil 12 of the portable wireless terminal 50 are disposed close to each other and faced to each other. Power is supplied from 60 to the portable wireless terminal 50. At this time, the non-contact power transmission coil 63 and the first coil 12 are electromagnetically coupled, and charging power is transmitted in a non-contact manner through both coils. The resonance frequency f1 for feeding power from the non-contact power transmission coil 63 to the first coil 12 is determined by the capacitor 54 connected in parallel to the first coil 12 and the capacitor 64 connected in parallel to the non-contact power transmission coil 63. Adjusted, where f1 = 100 kHz. The AC power generated and output in the AC power supply circuit 61 is transmitted from the non-contact power transmission coil 63 to the first coil 12 and is received by the portable radio terminal 50. The transmitted AC power is rectified by the rectifier circuit 55 and converted into DC power, and the DC output is supplied to the battery unit 58 for charging. Note that it is also possible to supply a direct current output to a circuit in the portable wireless terminal 50 to serve as an operating power source for each unit.

  When performing non-contact wireless communication, the non-contact wireless communication coil 73 of the reader / writer device 70 and the second coil 22 of the portable wireless terminal 50 are arranged close to each other so as to face each other. Data is transmitted to and received from the wireless terminal 50. At this time, the non-contact wireless communication coil 73 and the second coil 22 are electromagnetically coupled, and data transmission of non-contact wireless communication is performed via both coils. The resonance frequency f2 for communication between the non-contact wireless communication coil 73 and the second coil 22 is connected in parallel to the capacitor 56 connected in parallel to the second coil 22 and the non-contact wireless communication coil 73. Adjusted by capacitor 74, where f2 = 13.56 MHz. Data transmitted from the reader / writer device 70 to the portable wireless terminal 50 is modulated by the modulation / demodulation circuit 71, transmitted from the non-contact wireless communication coil 73 to the second coil 22, and received by the portable wireless terminal 50. The transmitted data is demodulated in the modulation / demodulation circuit 57 of the portable radio terminal 50. Data transmitted from the portable wireless terminal 50 to the reader / writer device 70 is modulated by the modulation / demodulation circuit 57, transmitted from the second coil 22 to the non-contact wireless communication coil 73, and received by the reader / writer device 70. The transmitted data is demodulated by the modulation / demodulation circuit 71 of the reader / writer device 70. In this way, using the contactless wireless communication function of the portable wireless terminal 50, data can be written to and read from the reader / writer device 70 to the portable wireless terminal 50 by contactless wireless communication.

(Example of coil unit)
Next, the Example which measured about the performance of the coil unit of this embodiment using the actually produced evaluation sample is shown. 6A and 6B are diagrams illustrating an example of dimensions of the coil unit according to the embodiment. FIG. 6C is a plan view of the coil unit according to the embodiment. FIG. 6D is a cross-sectional view taken along line AA ′ of FIG. 6 (A) shows only the first coil 12 laminated on the surface of the first magnetic body 11, FIG. 6 (B) shows only the second coil 22 laminated on the surface of the second magnetic body 21, 6C shows a coil unit in which the first coil 12 and the second coil 22 are combined and coexisted, and FIG. 6D shows a cross section of the coil unit shown in FIG. 6C.

  In the embodiment, the first magnetic body 11 has a square shape with a side a = 40 mm, the first coil 12 has a circular shape with an outer diameter b = 29 mm, and the second magnetic body 21 has a substantially central portion of a square with a side c = 40 mm. A square with one side d = 30 mm was cut out, and the thickness e of the coil unit was set to 1.0 mm. In this case, the outer peripheral dimensions of the first magnetic body 11 and the second magnetic body 21 are substantially matched and overlapped, and the first coil 12 and the second coil 22 are provided so as not to overlap. In particular, since the first coil 12 is circular and the second coil 22 is square, the distance between the first coil 12 and the second coil 22 is large at the four corners of the second coil 22.

  FIG. 7A is a diagram illustrating a result of measuring the power transmission efficiency during non-contact power transmission as the performance of the coil unit according to the example. FIG. 7B is a diagram illustrating a result of measuring the maximum communication distance during non-contact wireless communication as the performance of the coil unit according to the example. As for the power transmission efficiency, not the transmission efficiency of only the coil but the efficiency of the entire charging system including the direct current input of the AC power supply circuit of the charger as shown in FIG.

  In the state of the first coil 12 alone with the second coil 22 removed from FIG. 6D, the power transmission efficiency was 37.4 [%]. Further, in the state where the first coil 12 and the second coil 22 shown in FIG. 6D coexist, the power transmission efficiency was 38.2 [%]. In this case, it can be seen that the two coils coexist, and even if the second coil 22 is disposed outside the first coil 12, performance degradation due to electromagnetic coupling does not occur in non-contact power transmission.

  In the state of the 2nd coil 22 single-piece | unit which removed the 1st coil 12 from FIG.6 (D), the maximum communication distance was 141 [mm] and the dead area (Null area | region) did not arise. Further, in the state where the first coil 12 and the second coil 22 shown in FIG. 6D coexist, the maximum communication distance is 130 [mm], and no dead area (Null area) is generated. In this case, two coils coexist, and if the first coil 12 is disposed in the vicinity of the second coil 22, performance degradation due to electromagnetic coupling occurs in non-contact wireless communication, but compared to a comparative example described later. It can be seen that the amount of deterioration is small.

(Comparison example of coil unit)
Next, the comparative example measured using the evaluation sample of the coil unit which concerns on the comparative example for comparing with the performance of the coil unit of this embodiment is shown. 8A and 8B are diagrams illustrating an example of the dimensions of the coil unit according to the comparative example. FIG. 8C is a plan view of a coil unit according to a comparative example. FIG. 8D is a cross-sectional view taken along line AA ′ of FIG. 8A shows only the first coil 12 laminated on the surface of the first magnetic body 11, and FIG. 8B shows only the second coil 22 in the state where the second magnetic body 21 is not provided. 8C shows a coil unit in which the first coil 12 and the second coil 22 are combined and coexisted, and FIG. 8D shows a cross section of the coil unit shown in FIG. 8C.

  In the comparative example, the first magnetic body 11 has a square shape with a side a = 40 mm, the first coil 12 has a circular shape with an outer diameter b = 29 mm, and the second coil 22 starts from a substantially central portion of the square with a side c = 40 mm. It was configured within a range of a shape in which a square with one side d = 30 mm was cut out, and the second coil 22 and the first magnetic body 11 were brought into close contact with each other so as to have a thickness e = 0.8 mm. In this case, the first coil 12 and the second coil 22 are provided so as not to overlap. In particular, since the first coil 12 is circular and the second coil 22 is square, the distance between the first coil 12 and the second coil 22 is large at the four corners of the second coil 22.

  FIG. 9A is a diagram illustrating a result of measuring power transmission efficiency during non-contact power transmission as the performance of the coil unit according to the comparative example. FIG. 9B is a diagram illustrating a result of measuring the maximum communication distance during non-contact wireless communication as the performance of the coil unit according to the comparative example. As for the power transmission efficiency, not the transmission efficiency of only the coil but the efficiency of the entire charging system including the direct current input of the AC power supply circuit of the charger as shown in FIG.

  In the state of the single first coil 12 with the second coil 22 removed from FIG. 8D, the power transmission efficiency was 39.1 [%]. Moreover, in the state where the first coil 12 and the second coil 22 shown in FIG. 8D coexist, the power transmission efficiency was 38.8 [%]. In this case, it turns out that there is no big difference regarding the power transmission performance in the coil unit which concerns on an Example, and the coil unit which concerns on a comparative example.

  In the state of the 2nd coil 22 single-piece | unit which removed the 1st coil 12 from FIG.8 (D), since the 2nd magnetic body is not provided and the 2nd coil 22 closely_contact | adheres to a 1st magnetic body, the maximum communication distance is Although it remained at 131 [mm], a dead area (Null area) did not occur. Further, in the state where the first coil 12 and the second coil 22 shown in FIG. 8D coexist, the maximum communication distance is 117 [mm], and no insensitive area (Null area) is generated. In this case, since the two coils coexist and the second magnetic body 21 is not provided corresponding to the second coil 22, the maximum communication distance is further deteriorated due to electromagnetic coupling between the coils.

  Thereby, the coil unit according to the embodiment provides the second magnetic body 21 corresponding to the second coil on the surface of the first magnetic body 11 and outside the first coil 12, thereby enabling non-contact wireless communication. Generation of electromagnetic coupling can be suppressed and the maximum communication distance can be improved.

  Thus, according to the present embodiment, when a plurality of coils of the first coil 12 and the second coil 22 coexist, electromagnetic coupling between the coils can be reduced, and performance degradation due to electromagnetic coupling can be suppressed. In addition, by arranging the coils close to each other in such a configuration in which a plurality of magnetic bodies are laminated on the coil, the arrangement area can be reduced, and a coil with little performance deterioration can be easily manufactured in a small space. For this reason, in the portable wireless terminal equipped with the coil unit including the coil for contactless wireless communication according to the present embodiment, it is possible to suppress performance degradation during both contactless power transmission and contactless wireless communication while achieving downsizing. The desired performance (power transmission performance, communication performance) can be obtained by using a coil unit that can be easily manufactured in a space-saving manner.

(Second Embodiment)
FIG. 10 is a plan view showing the configuration of the coil unit according to the second embodiment. FIG. 11A is a cross-sectional view taken along the line AA ′ of FIG. FIG. 11B is a cross-sectional view taken along line BB ′ in FIG. In the description of FIGS. 10 and 11A and 11B, the same components as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted. 11A and 11B, the wiring patterns from the first terminal 31 and the second terminal 32 to the first coil 12 and the second coil 22 are shown in order to avoid complication of the drawing. Is omitted.

  The second embodiment is an example in which the shapes of the second magnetic body 21 and the second coil 22 in the first embodiment are changed. 11 A of 1st magnetic bodies and 12 A of 1st coils are the structures substantially the same as 1st Embodiment. That is, the first magnetic body 11A is formed in a rectangular plate shape, and the first coil 12A is configured by using a coil in which a conductor winding is wound in an elliptical ring shape. The second magnetic body 21A is formed in an elliptical annular plate shape, and the second coil 22A is wound in an elliptical shape by a conductor wiring pattern formed on the surface of the substrate 30A in the direction opposite to the arrow H in FIG. It is comprised using the coil formed.

  Similarly to the first embodiment, the coil unit of the present embodiment has an arrow H direction (mobile radio) from the lower side of FIG. 11 in the coil thickness direction (vertical direction in FIGS. 11A and 11B). The first coil 12A and the second magnetic body 21A are stacked on the surface of the first magnetic body 11A and the first magnetic body 11A (in the direction of the inner wall side of the back casing of the terminal). In addition, on the surface of the second magnetic body 21A, in the thickness direction of the coil, the second coil 22A, the substrate, from the lower side of FIG. Laminated in order of 30A. When viewed from the external device side, that is, the inner wall side of the back casing of the portable wireless terminal, the substrate 30A, the second coil 22A, the second magnetic body 21A, the first coil 12A, and the first magnetic body 11A are stacked in this order. The

  The first coil 12A and the second coil 22A are arranged so as not to overlap in the coil thickness direction.

  With such a configuration, similarly to the first embodiment, even when two coils are in close proximity to each other, electromagnetic coupling between both coils can be reduced, and performance degradation due to electromagnetic coupling can be suppressed. Further, the size can be reduced by arranging the two coils together.

(Background to the third embodiment)
Next, when the position shift occurs between the first coil and the second coil, that is, when the distance (interval) between the first coil and the second coil is decreased, the performance of the coil unit. It will be described with reference to FIG. 12 and FIG.

  FIG. 12 is a diagram for explaining the distance between the first coil 12 and the second coil 22. Here, the code | symbol of each part of a coil unit is demonstrated using the same code | symbol as 1st Embodiment.

  FIG. 12A is a plan view showing the configuration of the coil unit. FIG. 12B is an enlarged view of the region g in FIG. 12A, and the distance between the first coil 12 and the second coil 22 is appropriate. FIG. 12C is an enlarged view of the region g in FIG. 12A, and a positional deviation occurs so that the interval between the first coil 12 and the second coil is narrowed.

  Specifically, in the upper right portion of FIG. 12 (B), the distance between the left end portion of the second magnetic body 21 on which the second coil 22 is disposed and the right end portion of the first coil 12 is 1.20 mm. In the lower left part of the figure, the distance between the upper end of the second magnetic body 21 on which the second coil 22 is arranged and the lower end of the first coil 12 is 1.08 mm. In the description of FIG. 12 and FIG. 13, the arrangement condition in which the distance between the first coil 12 and the second coil 22 shown in FIG.

  Next, in the upper right part of FIG. 12C, the distance between the left end part of the second magnetic body 21 on which the second coil 22 is arranged and the right end part of the first coil 12 is 0.01 mm. In the lower left part of the figure, the distance between the upper end of the second magnetic body 21 on which the second coil 22 is arranged and the lower end of the first coil 12 is 0.01 mm. 12 and 13, the distance between the first coil 12 and the second coil 22 shown in FIG. 12C is relatively narrower than the distance shown in FIG. Let condition be condition b.

  FIG. 13A is a table showing measurement results under conditions a and b. FIG. 13B is a graph showing measurement results under conditions a and b. This measurement was performed in both cases where the coil unit was placed on a copper plate and when it was not placed. The table shown in FIG. 13A represents measured values of inductance (L value), resistance value (R value), and resonance frequency. The graph shown in FIG. 13B represents a change in the resonance frequency when there is no copper plate. In FIG. 13B, the horizontal axis indicates the frequency, and the vertical axis in FIG. 13 indicates the S parameter / S21 characteristic indicating the pass characteristic.

  13A and 13B, the resonance frequency in condition b is 13.66 (13 with respect to the original resonance frequency in condition a of 13.56 MHz in both cases with and without a copper plate. .67) MHz, which is a value shifted by about 100 kHz. Thus, the resonance frequency shifts due to the positional shift between the second coil and the first coil. For this reason, the performance of the coil unit, that is, the power transmission efficiency during non-contact power transmission and the maximum communication distance during non-contact wireless communication are deteriorated.

(Third embodiment)
Therefore, in the third embodiment, when the coil unit is assembled, positional deviation is prevented from occurring between the second coil and the first coil. That is, in the third embodiment, when assembling the coil unit, the interval between the first coil and the second coil is configured to be equal to or greater than a predetermined interval to prevent performance deterioration due to the positional deviation of each coil. An example of the coil unit will be described.

  First, the assembly of the coil unit will be briefly described. 14A to 14C are cross-sectional views illustrating the flow of assembling the coil unit. FIG. 14A shows an example of the first step of assembling the coil unit, FIG. 14B shows another example of the first step of assembling the coil unit, and FIG. 14C shows the assembly of the coil unit. Indicates the completion time.

  Prior to one example of the first step or another example, a partial coil unit is prepared in which the second coil 22 formed as a copper foil pattern (metal pattern) on the substrate 30 is attached to the second magnetic body 21. Keep it.

  In an example of the first step shown in FIG. 14A, the first coil 12 is pasted on the surface of the first magnetic body 11, and the partial coil unit is moved to the outside of the first coil 12. 1 Affix on the magnetic body 11.

  On the other hand, in another example of the first step shown in FIG. 14B, the second coil unit is first pasted on the first magnetic body 11, and the second step is so as to be positioned inside the partial coil unit. One coil 12 is pasted on the first magnetic body 11.

  Then, the assembly of the coil unit is completed as shown in FIG.

  In the case of assembling the coil unit according to any procedure of FIG. 14 (A) or (B), the distance (interval) between the first coil 12 and the second coil 22 arranged on the first magnetic body 11 is It is necessary to perform positioning so as not to affect the power transmission performance and the wireless communication performance of the coil unit, that is, at a predetermined interval or more.

  In the third embodiment, a guide member for guiding the first coil 12 or the partial coil unit is formed on the second magnetic body 21 or the substrate 30, and the distance between the first coil and the second coil when the coil unit is assembled. (Interval) was set to be equal to or greater than a predetermined interval.

  Next, two examples (Examples 1 and 2) measured using evaluation samples prepared by simulation will be described.

  FIG. 15 is a diagram illustrating the configuration of the coil unit according to the first embodiment when the second magnetic body 21B is also used as the guide member 21g. 15A and 15B are diagrams illustrating an example of dimensions of the coil unit according to the first embodiment. FIG. 15C is a plan view of the coil unit according to the first embodiment. FIG. 15D is a cross-sectional view taken along line AA ′ of FIG.

  In Example 1, the first magnetic body 11B has a square shape with a side a = 40 mm, the first coil 12B has a circular shape with an outer diameter b = 29 mm, and the second magnetic body 21B has a substantially central portion of a square with a side c = 40 mm. From which a circular shape having an outer diameter d = 30 mm was cut out. The coil unit thickness e was set to 1.0 mm.

  In this case, the outer peripheral dimension of the first coil 12B and the inner peripheral dimension of the second coil 22B substantially coincide with each other, and the first coil 12B and the second coil 22B overlap on the surface of the first magnetic body 11B. The first coil 12B and the second coil 22B do not overlap in the coil thickness direction. In particular, since the first coil 12B is circular and the second coil 22B is square, the distance (interval) between the first coil 12B and the second coil 22B is large at the four corners of the second coil 22B.

  In the coil unit according to the first embodiment, the second magnetic body 21B also serves as the guide member 21g. That is, the guide member 21g as a guide portion is formed on the inner peripheral edge of the second magnetic body 21B.

  Accordingly, the inner hole of the second magnetic body 21B is formed in a circular shape instead of a square, and the arc-shaped portion protruding from the four corners corresponding to the outer corners of the second magnetic body 21B itself toward the center inner side (FIG. 15B )) Corresponds to the guide member 21g. In this way, the guide member 21g guides the first coil 12B to the position inside the hole of the second magnetic body 21B, or the hole of the second magnetic body 21B to the position outside the first coil 12B. By guiding in a fixed manner, no displacement occurs in the distance (interval) between the first coil 12B and the second coil 22B.

  Thus, since the guide member 21g is formed in the peripheral part inside the 2nd magnetic body 21B (1st coil 12B side), the coil unit which concerns on Example 1 is substantially the same thickness as the 1st coil 12B. Thus, it is possible to regulate the positional deviation of the distance (interval) between the first coil 12B and the second coil 22B, and the positioning of the first coil 12B and the second coil 22B can be executed accurately.

  Next, FIG. 16 is a diagram illustrating a configuration of the coil unit according to the second embodiment when both the second magnetic body 21B and the substrate 30C are used as the guide members 21g and 30g, respectively. 16A and 16B are diagrams illustrating an example of dimensions of the coil unit according to the second embodiment. FIG. 16C is a plan view of the coil unit according to the second embodiment. FIG. 16D is a cross-sectional view taken along line AA ′ in FIG.

  In the coil unit according to the second embodiment, as in the coil unit according to the first embodiment, the first magnetic body 11B has a square shape with a side a = 40 mm, the first coil 12B has a circular shape with an outer diameter b = 29 mm, and the second The magnetic body 21B was configured as a shape in which a circle having an outer diameter d = 30 mm was cut out from a substantially central portion of a square having a side c = 40 mm. The coil unit thickness e was set to 1.0 mm.

  In the coil unit according to the second embodiment, like the coil unit according to the first embodiment, the guide member 21g is formed on the inner peripheral edge of the second magnetic body 21B, and the guide member is also formed on the inner peripheral edge of the substrate 30C. 30 g is formed.

  That is, the hole on the inner side of the substrate 30C is formed in a circular shape like the second magnetic body 21B, and arc-shaped portions protruding from the four corners corresponding to the outer corners of the second magnetic body 21B itself to the center inner direction are guide members. It corresponds to 30g. As described above, the guide members 30g and 21g guide the first coil 12B to the position inside the hole of the second magnetic body 21B, or the hole of the second magnetic body 21B outside the first coil 12B. By guiding the position fixedly, no positional deviation occurs in the distance (interval) between the first coil 12B and the second coil 22B.

  When the substrate 30C also serves as the guide member 30g, that is, when the guide member 30g is formed on the substrate 30C, the function as the guide member can be achieved without forming the guide member 21g inside the second magnetic body 21B. It is filled. However, in this case, it is desirable that the lower surface of the substrate 30C is positioned below the upper surface of the first coil 12B, and accurate positioning of the distance (interval) between the first coil 12B and the second coil 22B is achieved. It becomes possible.

  As described above, by forming the inner peripheral edge of the substrate 30C on the guide member 30g, the guide member can be easily molded, and the guide member can be easily formed into various shapes.

  FIG. 17 is a diagram illustrating a configuration of a coil unit according to a comparative example in which no guide member is provided. FIGS. 17A and 17B are diagrams illustrating an example of dimensions of a coil unit according to a comparative example. FIG. 17C is a plan view of a coil unit according to a comparative example. FIG. 17D is a cross-sectional view taken along line AA ′ of FIG.

  In the coil unit according to the comparative example, as in the coil unit according to Example 1 or 2, the first magnetic body 11B has a square shape with a side a = 40 mm, the first coil 12B has a circular shape with an outer diameter b = 29 mm, The two magnetic bodies 21B were configured as a square shape with a side c = 40 mm and a square with an outer diameter d = 30 mm cut out. The coil unit thickness e was set to 1.0 mm.

  Since this comparative example is the same as the example of the first embodiment (see FIGS. 6A to 6D), the same reference numerals are used. In this case, there is no protruding portion that becomes a guide member inside the substrate 30 and the second magnetic body 21, and a square hole is still formed. Accordingly, the first coil 12 and the like are stuck on the surface of the first magnetic body 11 without being guided by the guide member.

  FIG. 18 is a diagram illustrating measurement results of the performance of the coil units according to the first and second embodiments. FIG. 18A is a diagram illustrating a measurement result of power transmission efficiency during non-contact power transmission. FIG. 18B is a diagram illustrating a measurement result of the maximum communication distance during contactless wireless communication. The power transmission efficiency is not the efficiency of only the coil (first coil), but the efficiency of the entire charging system including the DC input of the AC power supply circuit of the charger as shown in FIG. 5 to the DC output of the portable wireless terminal. Was measured.

  As shown in FIG. 18A, in the coil unit according to the example in the first embodiment, the power transmission efficiency was 38.2 [%]. On the other hand, in each coil unit according to Examples 1 and 2 in the third embodiment, the power transmission efficiency was 38.1 [%]. Thus, in each coil unit which concerns on both Examples, the difference of electric power transmission efficiency did not arise.

  As shown in FIG. 18B, in the coil unit according to the example in the first embodiment, the maximum communication distance is 130 [mm], and no dead area (Null area) is generated. On the other hand, also in each of the coil units according to Examples 1 and 2 of the third embodiment, the maximum communication distance by the second coil 22B was 131 [mm], and no insensitive area (Null area) was generated. Thus, in each coil unit concerning both Examples, the difference of the maximum communication distance did not arise.

  Moreover, although not shown in each table shown in FIG. 18, each resonance frequency of the coil unit according to Examples 1 and 2 of the third embodiment is 13.56 MHz, as in the example of the first embodiment. There was no difference in resonance frequency between them. Similarly, there was no difference between the inductance (L value) and the resistance value (R value).

  As described above, when assembling the coil unit, the coil unit according to the third embodiment is configured so that the distance (interval) between the first coil and the second coil is fixed by the guide member. Since the arrangement position of the coil is regulated, there is no positional deviation between the first coil and the second coil, and the interval between the first coil and the second coil is equal to or greater than a predetermined interval. Thereby, when performing the wireless communication by the second coil, the coil unit according to the present embodiment can suppress deterioration of communication performance, in particular, a significant shift in the resonance frequency.

  19A to 19C are diagrams illustrating examples of various guide member shapes. 20D to 20F are diagrams illustrating other examples of the shapes of various guide members, following FIGS. 19A to 19C. Similar to the coil units according to Examples 1 and 2 of the third embodiment described above, the guide member may be formed on either the substrate or the second magnetic body. 19 and 20 show various shapes of the guide member when the guide member is formed on the second magnetic body, for example.

  FIG. 19A shows the structure of the guide member in the coil unit shown in FIG. That is, in FIG. 19A, the guide member 21g protruding from the four corners corresponding to the outer corners of the second magnetic body 21B itself is formed inside the second magnetic body 21B. In the guide member 21g, a peripheral edge portion of the guide member 21g facing the first coil 12B is formed in an arc shape so as to follow the shape of the first coil 12B having a circular shape. Here, the guide members 21g are formed for all the four corners corresponding to the outer corners of the second magnetic body 21B itself, but the coil unit is assembled as long as it is formed at least in one place. It can function as a guide.

  In FIG. 19B, the guide member 21h protruding from the four corners corresponding to the outer corners of the second magnetic body 21B itself inside the second magnetic body 21B faces the first coil 12B. The peripheral edge is formed in a straight line. Here, the guide member 21h is formed at all four corners corresponding to the outer corners of the second magnetic body 21B itself, but the coil unit is assembled as long as it is formed at least in one place. It can function as a guide.

  In FIG. 19C, a quadrangular (for example, square or rectangular) guide member 21i is formed in the center inward direction at the four corners corresponding to the outer corners of the second magnetic body 21B itself inside the second magnetic body 21B. It is formed to protrude. Further, one corner of each guide member 21i is close to the first coil 12B. Here, the guide members 21i are formed at all of the four inner corners of the second magnetic body 21B. However, as long as the guide members 21i are formed at least in one place, the guide members 21i can function as guides when assembling the coil unit. Is possible.

  In FIG. 20D, the convex guide member 21j protrudes to the position of the substantially middle point of each peripheral edge (each side) where the square hole is formed inside the second magnetic body 21B. ing. The tip of each guide member 21j is close to the first coil 12B. Here, the guide member 21j is formed on all four sides forming the inner peripheral edge of the second magnetic body 21B. However, as long as the guide member 21j is formed at least in one place, the coil unit is assembled. It is possible to function as a guide.

  FIG. 20E shows a case where the shape of the first coil 12C is a rounded square. Inside the second magnetic body 21B, guide members 21k are formed protruding from the four corners corresponding to the outer corners of the second magnetic body 21B itself toward the center inner side. The inner peripheral edge of the guide member 21k is formed in a substantially arc shape so as to follow the rounded shape of the first coil 12C. Here, the guide members 21k are formed at all four corners corresponding to the outer corners of the second magnetic body 21B itself, but the coil unit is assembled as long as it is formed at least in one place. It can function as a guide.

  FIG. 20F shows a case where the shape of the first coil 12C is a rounded quadrangle, as in the case of FIG. The peripheral portion of the lower right corner inside the second magnetic body 21B is formed on a substantially arc so as to follow the rounded shape of the first coil 12C, and is formed in a convex shape on both sides thereof. Is formed so as to protrude toward the center inner side of the second magnetic body 21B. The guide member 21l may be formed at two or more corners.

  The present invention is intended to be variously modified and applied by those skilled in the art based on the description in the specification and well-known techniques without departing from the spirit and scope of the present invention. Included in the scope for protection. In addition, the constituent elements in the above-described embodiment may be arbitrarily combined without departing from the spirit of the invention.

  For example, in the above embodiment, the guide member is formed as a part of the second magnetic body or the substrate. However, the guide member is separate from the second magnetic body or the substrate, and the material is the same or different. May be formed. In this case, a new member is added to the coil unit, but a guide member having an arbitrary shape can be easily provided without changing the shape of the second magnetic body or the substrate.

  The coil shape may be any shape such as a quadrangle, a circle, and an ellipse, and is not particularly limited.

  In each of the above embodiments, the coil units are described as being arranged in the vertical direction for easy understanding, but may be arranged in any direction such as the horizontal direction.

  The present invention has an effect that, when a plurality of coils such as a non-contact wireless communication coil and a non-contact power transmission coil coexist, it is possible to easily manufacture in a space-saving manner while suppressing performance deterioration of each coil. For example, it is useful as a non-contact radio communication coil capable of non-contact radio communication such as a mobile phone terminal and a smartphone, and a mobile radio terminal equipped with the coil.

11, 11A, 11B 1st magnetic body 12, 12A, 12B, 12C 1st coil 21, 21A, 21B, 21C 2nd magnetic body 21g, 21h, 21i, 21j, 21k, 21l Guide member 22, 22A, 22B 2nd Coil 30, 30A, 30B, 30C Substrate 31 First terminal 32 Second terminal

Claims (7)

A first coil that receives power using contactless power transmission ;
A second coil used for wireless communication ;
A first magnetic body having a predetermined magnetic permeability;
A second magnetic body having a magnetic permeability different from the predetermined magnetic permeability of the first magnetic body,
Disposing the first coil on the surface of the first magnetic body;
Disposing the second magnetic body on the surface of the first magnetic body and outside the first coil;
A transmission coil in which the second coil is disposed on a surface of the second magnetic body. The transmission coil according to claim 1,
A transmission coil in which the magnetic permeability of the first magnetic body is higher than the magnetic permeability of the second magnetic body. The transmission coil according to claim 1 or 2,
A transmission coil in which a resonance frequency of the first coil is lower than a resonance frequency of the second coil. The transmission coil according to any one of claims 1 to 3,
A transmission coil further comprising: a guide portion that guides the first coil and the second coil such that a distance between the first coil and the second coil is a predetermined distance or more. The transmission coil according to claim 4,
The guide portion is a transmission coil formed on a peripheral portion of the second magnetic body on the first coil side. The transmission coil according to claim 4 or 5,
A substrate disposed outside the first coil, wherein the second coil is formed as a predetermined metal pattern, and
The guide portion is a transmission coil formed on a peripheral portion of the substrate on the first coil side. Portable wireless terminal equipped with the transmission coil according to any one of claims 1-6.

Images