CN101657938B - Magnetic field coupling type antenna, magnetic field coupling type antenna module, magnetic field coupling type antenna device, and their manufacturing methods - Google Patents

Abstract

Disclosed is a magnetic field coupling type antenna comprising an insulating layer (110) and a magnetic core (112) embedded in the insulating layer (110). A coil having a coil axis parallel to the upper surface of the insulating layer is formed by an upper conductor (116) formed on the upper surface of the insulating layer (110), a lower conductor (118) formed on the lower surface of the insulating layer (110), a lateral conductor (120) for electrically connecting the upper conductor (116) and the lower conductor (118), and a via (122). This magnetic field coupling type antenna can be manufactured by a simple process and has high antenna sensitivity without deteriorating impact resistance.

Description

Magnetic field coupling type antenna, magnetic field coupling type antenna module, magnetic field coupling type antenna device, and manufacturing method thereof

technical field

The present invention relates to a magnetic field coupling antenna, a magnetic field coupling antenna module, and a magnetic field coupling antenna device used in an RFID (Radio Frequency Identificaiton) system that communicates with external devices via electromagnetic field signals, and their manufacturing methods.

Background technique

In recent years, in the RFID system whose use has been expanding, portable electronic devices such as mobile phones and a reader/writer are each equipped with an antenna for information communication to transmit and receive data to each other. An antenna for RFID is generally a magnetic field coupling type antenna having a structure in which a coil is wound around a magnetic core. Among them, especially for a magnetic field coupling antenna mounted on a portable electronic device, improvement in shock resistance that does not change the antenna characteristics due to shock such as dropping is required. One of the causes of changes in antenna characteristics due to external shocks is damage to the magnetic core due to the shocks.

As a measure to prevent changes in antenna characteristics caused by damage to the magnetic core, Patent Document 1 proposes the following shape of a magnetic field coupling antenna (hereinafter, the magnetic field coupling antenna is simply referred to as an antenna). 15-A and 15-B are diagrams showing the structure of the antenna described in Patent Document 1, FIG. 15-A is a plan view, and FIG. 15-B is a cross-sectional view of the A-A cross-sectional view of FIG. 15-A.

In the antenna 1000 shown in FIGS. 15-A and 15-B , a magnetic core member 1012 is interposed between two insulating layers 1010 a and 1010 b. In addition, the antenna 1000 includes an upper surface conductor 1016 formed on the upper surface of the upper insulating layer 1010a, a lower surface conductor 1018 formed on the lower surface of the lower insulating layer 1010b, and a connection connecting the upper surface conductor 1016 and the lower surface conductor 1018. Conductor 1020. The coil 1014 is formed around the insulating layers 1010a and 1010b by the upper surface conductor 1016, the lower surface conductor 1018, and the connecting conductor 1020. Furthermore, the connecting conductor 1020 is a through hole formed between the upper surface of the upper insulating layer 1010a and the lower surface of the lower insulating layer 1010b. The upper surface conductor 1016 and the lower surface conductor 1018 are electrically connected by the plating layer formed on the inner wall of the through hole.

With the structure in which the magnetic core member 1012 is sandwiched between the insulating layers 1010a and 1010b, the impact applied to the entire antenna 1000 is not directly applied to the magnetic core member 1012 . Therefore, the magnetic core member 1012 is less likely to be damaged, and the change in antenna characteristics due to the damage of the magnetic core member 1012 is less likely to occur.

Patent Document 1: Japanese Unexamined Patent Publication No. 2005-184094.

Contents of the invention

In the antenna 1000, the magnetic core member 1012 is formed by applying a paint containing a magnetic material to the lower insulating layer 1010b. Then, the upper insulating layer 1010 a is bonded to the lower insulating layer 1010 b so as to cover the magnetic core member 1012 .

In the RFID antenna, magnetic flux from the outside passes through the coil axis of the coil to generate an induced voltage, thereby performing communication. At this time, since the magnetic core, that is, the magnetic core member in Patent Document 1, guides the magnetic flux so as to pass through the coil axis, it needs to have a thickness greater than a certain level in order to realize high antenna sensitivity. However, according to the method of forming the magnetic core member 1012 by applying paint, there is a problem that only a very thin magnetic core member can be formed. In addition, there is a problem that repeated application is required in order to increase the thickness.

In addition, the antenna 1000 described in Patent Document 1 also discloses a method of using the plate-shaped core member 1012 . Specifically, an insulating member is attached around the planar core member 1012, and the planar magnetic core member 1012 and the insulating member form the same cross-sectional shape as the insulating layers 1010a and 1010b. Furthermore, there is also a method of sandwiching the magnetic core member 1012 between the insulating layers 1010a and 1010b. According to this method, it can be seen that an unnecessary step of affixing an insulating member is required, making it difficult to easily manufacture the antenna 1000 .

Therefore, an object of the present invention is to realize a magnetic field coupling antenna that is easy to manufacture and has high antenna sensitivity while maintaining the shock resistance.

In order to solve the above-mentioned problems, the present invention has the configurations described below.

The magnetic field coupling antenna according to the present invention includes: an insulating layer; a magnetic core embedded in the insulating layer; an upper surface conductor formed on the upper surface of the insulating layer; and a lower surface formed on the lower surface of the insulating layer. a conductor; a connecting conductor electrically connecting the upper surface conductor and the lower surface conductor, wherein the upper surface conductor, the lower surface conductor and the connecting conductor are used to form a The coil of the coil shaft.

In the magnetic field coupling antenna of the present invention, the magnetic core may include a plurality of magnetic cores. Preferably, the direction in which the plurality of magnetic cores are arranged is a direction perpendicular to the coil axis of the coil.

Preferably, in the magnetic field coupling antenna of the present invention, the area of at least one of the surfaces of the magnetic core located at both ends in the coil axis direction is larger than the area of any cross section of the magnetic core perpendicular to the coil axis.

In the magnetic field coupling antenna of the present invention, a magnetic core may be provided on the side surface of the insulating layer positioned in the coil axis direction.

In the magnetic field coupling antenna of the present invention, the coil may be divided into a first coil portion and a second coil portion with a non-wound portion in between.

In the magnetic field coupling antenna of the present invention, at least a part of the connecting conductor may be formed by a through hole or a via electrically connected to the upper surface conductor or/and the lower surface conductor of the insulating layer. In addition, at least a part of the connecting conductor may be formed by a pattern previously formed on the side surface of the magnetic core, and the pattern may be electrically connected to the through hole or via.

The magnetic field coupling antenna module of the present invention is characterized by comprising: a magnetic field coupling antenna; and an electronic component embedded in an insulating layer. The electronic component is preferably a capacitor. In addition, the electronic component may be provided between the magnetic core and the connection conductor.

The magnetic field coupling antenna module of the present invention may include: a magnetic field coupling antenna; and a capacitor buried in the insulating layer, and the capacitor is provided in the non-winding portion.

In the magnetic field coupling antenna module of the present invention, a lower insulating layer may be further provided on the lower surface of the insulating layer, and a shield electrode layer may be formed on the lower surface of the lower insulating layer.

A magnetic field coupling antenna device according to the present invention includes: a magnetic field coupling antenna module; and an integrated circuit embedded in an insulating layer. In addition, in the magnetic field coupling antenna device, a shield layer may be formed on a portion of the upper surface of the insulating layer where the upper surface conductor is not formed.

The method of manufacturing a magnetic field coupling antenna of the present invention includes: a step of forming a lower surface conductor on a support plate or a substrate; a step of mounting a magnetic core on the support plate or substrate; The step of pressing the insulating layer in a semi-hardened state to the magnetic core, and embedding the magnetic core in the insulating layer; the step of hardening the insulating layer embedded with the magnetic core; A step of forming a connecting conductor electrically connected to the lower surface conductor on the insulating layer; forming an upper surface conductor electrically connected to the connecting conductor on the surface of the insulating layer opposite to the surface in contact with the lower surface conductor process.

The method for manufacturing a magnetic field coupling antenna module of the present invention includes: a step of forming a lower surface conductor on a support plate or a substrate; a step of mounting a magnetic core and a capacitor on the support plate or substrate; A step of pressing the semi-hardened insulating layer on the substrate, the magnetic core, and the capacitor, and embedding the magnetic core in the insulating layer; The step of hardening the insulating layer; the step of forming a connection conductor electrically connected to the lower surface conductor on the insulating layer; A process of upper surface conductors electrically connected to the connecting conductors.

The method for manufacturing a magnetic field coupling antenna device of the present invention includes: a step of forming a lower surface conductor on a support plate or a substrate; a step of mounting a magnetic core, a capacitor, and an integrated circuit element on the support plate or substrate; The step of pressing the insulating layer in a semi-hardened state on the support plate or substrate, the magnetic core, the capacitor, and the integrated circuit element, and embedding the magnetic core in the insulating layer; A step of hardening the insulating layer of the magnetic core, the capacitor, and the integrated circuit element; a step of forming a connection conductor electrically connected to the lower surface conductor in the insulating layer; A step of forming an upper surface conductor electrically connected to the connection conductor on a surface opposite to the surface in contact with the lower surface conductor.

Invention effect

According to the present invention, since the magnetic core is provided in the insulating layer, impact resistance is improved. In addition, since it is formed by embedding a magnetic core having a constant thickness, it can be easily manufactured and a magnetic field coupling antenna with high antenna sensitivity can be realized.

Description of drawings

FIG. 1 is a perspective view showing the structure of a magnetic field coupling antenna according to a first embodiment of the present invention.

2-A is a perspective view showing a method of manufacturing the magnetic field coupling antenna according to the first embodiment of the present invention.

2-B is a perspective view showing a method of manufacturing the magnetic field coupling antenna according to the first embodiment of the present invention.

2-C is a cross-sectional view showing a method of manufacturing the magnetic field coupling antenna according to the first embodiment of the present invention.

2-D is a cross-sectional view showing a method of manufacturing the magnetic field coupling antenna according to the first embodiment of the present invention.

2-E is a cross-sectional view showing a method of manufacturing the magnetic field coupling antenna according to the first embodiment of the present invention.

2-F is a cross-sectional view showing a method of manufacturing the magnetic field coupling antenna according to the first embodiment of the present invention.

3 is a perspective view showing a modified example of the magnetic field coupling antenna according to the first embodiment of the present invention.

4 is a diagram showing the structure of a magnetic field coupling antenna according to a second embodiment of the present invention.

5-A is a perspective view showing the structure of a magnetic field coupling antenna according to a third embodiment of the present invention.

5-B is a cross-sectional view showing the structure of a magnetic field coupling antenna according to a third embodiment of the present invention.

6 is a perspective view showing the structure of a magnetic field coupling antenna according to a fourth embodiment of the present invention.

7 is a perspective view showing the structure of a magnetic field coupling antenna according to a fifth embodiment of the present invention.

8 is a schematic diagram showing the flow of magnetic flux in a magnetic field coupling antenna according to a fifth embodiment of the present invention.

9 is a perspective view showing the structure of a magnetic field coupling antenna module according to a sixth embodiment of the present invention.

10 is a perspective view showing a modified example of the magnetic field coupling antenna module according to the sixth embodiment of the present invention.

11 is a perspective view showing the structure of a magnetic field coupling antenna device according to a seventh embodiment of the present invention.

12-A is a perspective view showing the structure of a magnetic field coupling antenna device according to an eighth embodiment of the present invention.

12-B is a cross-sectional view showing the structure of a magnetic field coupling antenna device according to an eighth embodiment of the present invention.

13-A is a perspective view showing a modified example of the magnetic field coupling antenna device according to the eighth embodiment of the present invention.

13-B is a cross-sectional view showing a modified example of the magnetic field coupling antenna device according to the eighth embodiment of the present invention.

14 is a perspective view showing the structure of a magnetic field coupling antenna device according to a ninth embodiment of the present invention.

Fig. 15-A is a plan view showing the structure of a conventional example.

Fig. 15-B is a cross-sectional view showing the structure of a conventional example.

In the figure: 100, 200, 300, 400, 500, 600-magnetic field coupling antenna; 601, 602-magnetic field coupling antenna module; 703, 803, 903-magnetic field coupling antenna device; 110-insulating layer; 112-magnetic Body core; 114-coil; 116-upper surface conductor; 118-lower surface conductor; 120-side conductor; 122-passage.

Detailed ways

"First Embodiment"

A first embodiment of the present invention will be described with reference to FIG. 1 . FIG. 1 is a perspective view showing the structure of a magnetic field coupling antenna according to a first embodiment. In the following description, the magnetic field coupling type antenna is simply referred to as an antenna.

The antenna 100 according to the first embodiment includes: an insulating layer 110 ; and a magnetic core 112 buried in the insulating layer 110 with one surface exposed from the lower surface of the insulating layer 110 . Embedding is a state in which the magnetic core 112 is surrounded by the insulating layer 110 by pressing the insulating layer 110 in a semi-cured state to the magnetic core 112 . As described in the present embodiment, a state where a part of the magnetic core 112 is exposed from the insulating layer 110 is also included.

The insulating layer 110 includes: a thermosetting resin or a mixture of a thermosetting resin and an inorganic filler. A ferrite plate is preferable as the magnetic core 112, and is formed into a rectangular parallelepiped. The thickness of the magnetic core 112 is designed to be an optimum thickness capable of realizing desired antenna sensitivity. In addition, an upper surface conductor 116 is formed on the upper surface of the insulating layer 110 , a lower surface conductor 118 is formed on the lower surface, a side conductor 120 is formed on the side surface, and a via 122 is formed inside. A connection conductor connecting the upper surface conductor 116 and the lower surface conductor 118 is formed by the side surface conductor 120 and the via 122 . Here, the via refers to a state in which a through-hole formed from the upper surface to the lower surface of the insulating layer 110 is filled. More specifically, it refers to filling with a conductive paste, or filling with a conductive paste or a non-conductive paste after forming a plating layer on the inner wall of the through hole, thereby electrically connecting the upper surface conductor 116 and the lower surface conductor. 118 status. Coil 114 having a coil axis parallel to the upper surface of insulating layer 110 is formed around insulating layer 110 by upper surface conductor 116 , lower surface conductor 118 , side conductor 120 constituting a connecting conductor, and via 122 . The end of the coil 114 is drawn out from the side of the insulating layer 110 for easy connection, and a connecting portion 126 is formed.

Since the magnetic core 112 is embedded in the insulating layer 110 , even if an impact is applied to the insulating layer 110 by dropping or the like, the impact is not directly applied to the magnetic core 112 , so the magnetic core 112 is not easily damaged. In the present embodiment, one side of the magnetic core 112 is exposed from the lower surface of the insulating layer 110 , but three sides are covered by the insulating layer 110 , so that the impact resistance can be improved. When all the surfaces of the magnetic core 112 are surrounded by the insulating layer 110 , the effect of improving the impact resistance is of course further enhanced.

In addition, the embedding of the magnetic core 112 in the insulating layer 110 is not affected by the thickness of the magnetic core 112 . That is, even when the thick insulating layer 110 is used, the magnetic core 110 is buried in the insulating layer 110 by a single step of pressing the semi-hardened insulating layer 110 to the magnetic core 110 . Therefore, the antenna sensitivity can be easily improved by selecting the thickness of the magnetic core according to the desired antenna sensitivity.

In addition, the antenna 100 is a magnetic field coupling type antenna in which an induced voltage is induced in the coil 114 when a magnetic flux passes through the coil axis of the coil 114 . The magnetic flux enters the magnetic core 112 from one of the side surfaces of the insulating layer 110 located in the coil axis direction, and is radiated from the other. When the flow of the magnetic flux is blocked, the magnetic flux passing through the coil axis of the coil 114 decreases, and the antenna sensitivity of the antenna 100 decreases. Therefore, it is preferable not to arrange an object obstructing the flow of the magnetic flux on both side surfaces of the magnetic core 112 located in the coil axis direction.

Hereinafter, a method of manufacturing the antenna 100 will be described with reference to FIGS. 2-A to 2-F. FIGS. 2-A to 2-F are perspective views showing respective manufacturing steps of the antenna 100 .

FIG. 2-A shows the lower surface conductor forming process. Lower surface conductors 118 are formed on a support plate or substrate 130 . The lower surface conductor 118 can be formed by a known method such as forming a plated layer on the support plate or the substrate 130 by electrolytic plating, and etching the plated layer. Hereinafter, a case where a transfer sheet containing SUS is used as a support sheet will be described.

FIG. 2-B shows a magnetic core mounting process. Magnetic core 112 is mounted on support plate 130 so as to overlap lower surface conductor 118 . The magnetic core 112 is fixed to the support plate 130 with an adhesive sheet, an adhesive, or the like.

FIG. 2-C shows the insulating layer forming process, and shows a cross section perpendicular to the upper surface of the insulating layer 110 . Insulating layer 110 is prepared in a state where copper foil 150 is attached to the upper surface in advance. The insulating layer 110 includes a thermosetting resin or a mixture of a thermosetting resin and an inorganic filler, which is in a semi-hardened state (prepreg). The insulating layer 110 is pressurized and heated from the magnetic core 112 side to the structure obtained through the above-mentioned magnetic core mounting step. Thus, the magnetic core 112 is buried in the insulating layer 110 . The lower surface of the magnetic core 112 is in contact with the support plate 130 , so the lower surface of the magnetic core 112 is not covered by the insulating layer 110 . Then, further heating hardens the insulating layer 110 .

FIG. 2-D shows a via formation process, and shows a cross section perpendicular to the upper surface of the insulating layer 110 . First, the copper foil 150 on the upper surface of the insulating layer 110 is etched to form an opening at a portion where a via should be formed. In addition, laser light is irradiated from the upper surface direction of the insulating layer 110 through the opening to form a through hole having the lower surface conductor 118 as a bottom surface. Then, after the plating layer 140 is formed by electroless plating and electrolytic plating on the inner wall of the through-hole, the non-conductive paste 142 is filled. The via 122 formed in this step constitutes a part of the connection conductor.

FIG. 2-E shows the upper surface conductor formation process, and shows a cross section perpendicular to the upper surface of the insulating layer 110 . The plating layer 152 is formed on the copper foil 150 attached in advance on the insulating layer 110 by electrolytic plating. The upper surface conductor 116 can be formed by simultaneously etching the plating layer 152 and the copper foil 150 . The upper surface conductor 116 overlaps the via 122 and is formed at a portion overlapping the magnetic core 112 when viewed from the upper surface direction of the insulating layer 110 .

FIG. 2-F shows a side conductor forming process. The side conductors 120 are formed by pattern printing on the side surfaces of the insulating layer 110 . The side conductor 120 is electrically connected to the upper surface conductor 116 and the lower surface conductor 118 . The side conductor 120 formed in this step constitutes a part of the connection conductor.

Through the above steps, the upper surface conductor 116 and the lower surface conductor 118 are electrically connected by the side surface conductor 120 and the via 122 , and the coil 114 is formed around the insulating layer 110 . Finally, the support plate 130 is peeled off from the lower surface conductor 118 and the insulating layer 110 to form the antenna 100 .

In this embodiment, the connection conductor is formed by the side conductor 120 formed on the side surface of the insulating layer 110 and the via 122 formed inside the insulating layer 110 . However, the present invention is not limited thereto. First, a via hole may be used instead of the via 122 . Here, the through hole refers to a state where the through hole formed between the upper surface and the lower surface of the insulating layer 110 is not filled. By forming a plating layer on the inner wall of the through hole, the upper surface conductor 116 and the lower surface conductor 118 are electrically connected. In addition, the connection conductors may be formed only of side conductors, or may be formed of only vias or through-holes.

In addition, in this embodiment, as shown in FIG. 1 , three patterns of coils 114 are formed. However, the present invention is not limited thereto. By increasing the number of upper surface conductors 116 , lower surface conductors 118 , side surface conductors 120 , and vias 122 , coils with a large number of patterns can be easily formed. Thereby, a coil with a high inductance value can be realized.

In addition, in this embodiment, the magnetic core 112 is formed as a rectangular parallelepiped, but it is preferable to chamfer the corners of the rectangular parallelepiped and form it into a rounded shape. When insulating layer 110 embedded with magnetic core 112 is cured and heat is applied to insulating layer 110 , moisture contained in insulating layer 110 vaporizes and the volume of the moisture increases, thereby generating stress in insulating layer 110 . Since this stress tends to concentrate on the corners of the magnetic core 112 embedded in the insulating layer 110, cracks may occur based on the corners. By chamfering the corners to give them roundness, stress can be dispersed and cracks can be prevented.

In addition, it is also effective to provide a cavity penetrating from the upper surface to the lower surface of the magnetic core 112 in the center of the magnetic core 112, and to form it in an annular shape. By forming the magnetic core 112 in an annular shape, when the insulating layer 110 is pressed against the magnetic core 112 , the resin constituting the insulating layer 110 also flows into the cavity provided in the center of the magnetic core 112 . Accordingly, the contact area between the magnetic core 112 and the insulating layer 110 increases, and thus the bonding strength between the magnetic core 112 and the insulating layer 110 increases. Accordingly, a stronger antenna 100 can be formed. However, the void preferably has a size that does not hinder the flow of magnetic flux passing through the inside of the magnetic core 112 .

(Modification)

Hereinafter, a modified example of the antenna 100 of the first embodiment will be described with reference to FIG. 3 . Fig. 3 is a perspective view showing a modified example of the antenna of the first embodiment.

In FIG. 3 , a magnetic core 112 is embedded in an insulating layer 110 . A pattern 160 is formed on one side surface of the magnetic core 112 . In addition, on the insulating layer 110 , a via 123 is formed between the upper surface of the insulating layer 110 and the upper surface of the magnetic core 112 . Via 123 and pattern 160 are formed at overlapping positions when viewed from the upper surface of insulating layer 110 , and these are electrically connected. The connection conductor includes a connection conductor 120 a formed on the side surface of the insulating layer 110 , a via 123 and a pattern 160 .

Magnetic core 112 in which pattern 160 is previously formed on the side surface is embedded in insulating layer 110 . After the magnetic core 112 is buried in the insulating layer 110 , the insulating layer 110 is cured to form the via 123 . Via 123 is formed from the upper surface of insulating layer 112 to the upper surface of magnetic core 112 , and therefore, the depth of via 123 in FIG. 3 is shallower than that of via 122 in FIG. 1 .

When forming a bottomed hole with a laser or the like and forming a plated layer on the inner wall of the bottomed hole, it is necessary to consider the ratio of the depth to the diameter of the bottomed hole, that is, the depth ratio. In FIG. 1 , the via 120b is formed with the lower surface conductor 118 as the bottom surface, so the diameter and depth of the bottomed hole need to be set in consideration of the depth ratio. Usually, when a depth ratio is 2 or more, it becomes difficult to form a plating layer to the bottom surface of a bottomed hole. Therefore, when the depth of the bottomed hole is deep, in order to form the plated layer up to the bottom surface of the bottomed hole, it is necessary to increase the diameter of the bottomed hole.

As described above, in this modified example, the passage 123 may be formed with a shallow depth, so the diameter of the bottomed hole may be small. Thus, vias 123 can be formed at a higher density. The pattern 160 formed on the side surface of the magnetic core 112, the upper surface conductor 116, the lower surface conductor 118, and the side surface conductor 120 formed on the side surface of the insulating layer 110 can also be formed at high density. Therefore, by increasing the number of vias 123 formed, The number of windings of the coil 114 can be increased.

"Second Embodiment"

A second embodiment of the present invention will be described with reference to FIG. 4 . 4 is a perspective view showing the structure of a magnetic field coupling antenna according to a second embodiment. The same reference numerals are attached to the same configurations as those of the first embodiment, and description thereof will be omitted. In the following description, the magnetic field coupling type antenna is simply referred to as an antenna.

In FIG. 4 , the antenna 200 has two magnetic cores 212 a and 212 b embedded in the insulating layer 110 . The magnetic cores 212a and 212b are respectively bisected from the magnetic core used in the first embodiment, and the total volume of the two magnetic cores 212a and 212b is equal to that of the first embodiment. The direction in which the magnetic cores 212a, 212b are arranged is a direction perpendicular to the coil axis of the coil 114, and the magnetic flux passing through the coil axis of the coil 114 passes through either one of the magnetic cores 212a, 212b. Therefore, the gap between the magnetic cores 212a and 212b does not hinder the flow of the magnetic flux passing through the coil axis of the antenna 200 .

By dividing the magnetic cores used in the first embodiment into two halves, the size of each magnetic core can be reduced while maintaining the sensitivity of the antenna. When stress such as bending is applied to the antenna 200 , the stress is also applied to the magnetic cores 212 a and 212 b via the insulating layer 110 . By reducing the size of each of the magnetic cores 212a, 212b, even if stress is applied to the magnetic cores 212a, 212b, damage such as cracking is less likely to occur.

The magnetic cores 212 a and 212 b are fixed together on a support plate, and the insulating layer 110 in a semi-cured state (prepreg) is pressurized and heated to be embedded in the insulating layer 110 at the same time. Therefore, it is very easy to manufacture the antenna 200 in which the two magnetic cores 212a, 212b are embedded.

In this embodiment, the magnetic cores 212a, 212b are arranged so that the direction in which the magnetic cores 212a, 212b are arranged is perpendicular to the coil axis of the coil 114. However, the present invention is not limited to this embodiment, and the magnetic cores may be The cores 212a, 212b are aligned along the coil axis of the coil 114 . In addition, three or more magnetic cores may be buried.

"Third Embodiment"

A third embodiment of the present invention will be described with reference to FIGS. 5-A and 5-B. 5 shows the structure of the magnetic field coupling antenna of the third embodiment, FIG. 5-A is a perspective view, and FIG. 5-B is a sectional view of the A-A section of FIG. 5-A. The same reference numerals are attached to the same configurations as those of the first embodiment, and description thereof will be omitted. In the following description, the magnetic field coupling type antenna is simply referred to as an antenna.

In FIGS. 5-A and 5-B , three cuboid magnetic cores 312 a , 312 b , and 312 c are buried in the insulating layer 110 . The three magnetic cores 312a, 312b, and 312c are arranged along the coil axis direction of the coil 114 . FIG. 5-B shows a cross section perpendicular to the upper surface of the insulating layer 110 and along the coil axis of the coil 114 . In this cross section, among the three magnetic cores 312a, 312b, 312c, the height of the two magnetic cores 312a, 312c located at both ends in the coil axis direction is higher than the height of the magnetic core 312b located in the center. That is, the areas of the surfaces located at both ends in the coil axis direction of the three magnetic cores 312a, 312b, and 312c are larger than the area of any cross section perpendicular to the coil axis of the magnetic cores 312a, 312b, and 312c. Magnetic flux from the outside of the antenna 300 enters either of the two magnetic cores 312a and 312c located at both ends in the coil axis direction. In these magnetic cores 312a and 312c, the area of the surface located in the coil axis direction of the coil 114 is enlarged, and therefore, the entrance of the magnetic flux is ensured considerably, and the magnetic flux enters more easily. In addition, the magnetic flux is emitted from the magnetic core different from the magnetic core into which the magnetic flux enters, among the magnetic cores 312a and 312c. Also here, since the area of the surface located in the direction of the coil axis is large, the exit of the magnetic flux is greatly ensured, and the magnetic flux is more easily radiated to the outside. Due to the structure in which magnetic flux is easy to enter and radiate, the amount of magnetic flux passing through the coil axis of the coil 114 increases, and the sensitivity of the antenna 300 increases.

By fixing all three magnetic cores 312 a , 312 b , and 312 c to the support plate, the insulating layer 110 in a semi-hardened state (prepreg) is pressed and embedded in the insulating layer 110 . According to such a manufacturing method, it is possible to form a structure in which magnetic flux easily enters and radiates without molding the magnetic core into a special shape.

In addition, in this embodiment, the magnetic cores having a large area are arranged at both ends in the coil axis direction, but the present invention is not limited to this embodiment. A certain effect can also be obtained only when it is arranged at either end. In addition, when a single magnetic core is molded so that the area of the surface located at both ends in the coil axis direction is larger than the area of any cross section perpendicular to the coil axis of the magnetic core, it is also easy to enter or radiate magnetic flux. The structure improves the antenna sensitivity. However, in this case, it is necessary to mold the magnetic core into a special shape.

"Fourth Embodiment"

A fourth embodiment of the present invention will be described with reference to FIG. 6 . 6 is a perspective view showing the structure of a magnetic field coupling antenna according to a fourth embodiment. The same symbols are assigned to the same structures as those in the first embodiment, and explanations thereof are omitted. In the following description, the magnetic field coupling type antenna is simply referred to as an antenna.

In FIG. 6 , the magnetic core 412 b is embedded in the insulating layer 110 . Furthermore, other magnetic cores 412 a and 412 c are provided on the side surfaces of the coil 114 located in the insulating layer 110 in the coil axis direction. The magnetic cores 412 a and 412 c are crimped to the insulating layer 110 in a semi-cured state, and can be provided on the side surfaces of the insulating layer 110 by curing the insulating layer 110 in the crimped state. The magnetic cores 412 a and 412 c are each formed to cover the entire side surfaces of the insulating layer 110 .

Magnetic cores 412 a and 412 c located at ends of coil 114 in the coil axis direction are formed to cover the entire side surface of insulating layer 110 , so antenna 400 can allow magnetic flux to enter from the entire side surface of coil 114 in the coil axis direction. In addition, it is also possible to radiate magnetic flux from the entire side surface in the same manner. Therefore, in the third embodiment, the amount of magnetic flux passing through the coil axis of the coil 114 is increased, and the antenna sensitivity is improved. The magnetic cores 412a, 412c are not covered by the insulating layer 110, so there is a possibility of damage, but the magnetic core 412b located in the center is not covered by the insulating layer, so even if the magnetic cores 412a, 412c are damaged, a certain level can be achieved. antenna sensitivity.

In this embodiment, the magnetic cores 412a, 412c are placed on the side surfaces of the insulating layer 110 by crimping the semi-cured insulating layer 110, but the magnetic cores 412a, 412c may be bonded together with an adhesive. connected to the side of the hardened insulating layer 110.

"Fifth Embodiment"

A fifth embodiment of the present invention will be described with reference to FIGS. 7 and 8 . 7 is a perspective view showing the structure of a magnetic field coupling antenna according to a fifth embodiment. FIG. 8 is a schematic diagram illustrating the route of magnetic flux in the fifth embodiment. The same reference numerals are attached to the same configurations as those of the first embodiment, and description thereof will be omitted. In the following description, the magnetic field coupling type antenna is simply referred to as an antenna.

In FIG. 7 , two magnetic cores 512 a and 512 b are embedded in the insulating layer 110 . The coil 514 is divided into a first coil portion 515 a and a second coil portion 515 b and wound, and a non-wound portion 570 in which no coil is formed is formed between the first coil portion 515 a and the second coil portion 515 b. The first coil part 515a is formed around the magnetic core 512a, and the second coil part 515b is formed around the magnetic core 512b.

In addition, in the coil 514 including the first coil part 515a and the second coil part 515b, the induced voltage is not caused by the magnetic flux passing through the same direction of the coil axis of each coil part 515a, 515b. The winding direction of the coil part 515a, 515b and the connection method of the two coil part 515a, 515b. More specifically, in FIG. 7 , the number of windings of the first coil portion 515 a and the second coil portion 515 b are equal to each other, and the winding directions are opposite when viewed from the same direction. In addition, when viewed from the same direction, the end of the first coil portion 515a and the start of the second coil portion 515b are connected to each other. If these form the first coil portion 515a and the second coil portion 515b, when the magnetic flux in the same direction passes through the coil axes of the first coil portion 515a and the second coil portion 515b, the first coil portion 515a and the second coil portion 515b The second coil portion 515b induces induced voltages in opposite directions. However, since the first coil portion 515 a and the second coil portion 515 b are connected to each other, voltages in opposite directions do not cancel each other out, and no induced voltage is induced in the coil 514 .

The operation of the antenna 500 will be described below with reference to FIG. 8 . FIG. 8 is a schematic diagram showing the passage of magnetic flux in the B-B cross section of FIG. 7 . As shown in FIG. 8 , the magnetic flux φ arriving from the upper surface direction of the antenna 500 enters the non-winding portion 570 provided between the two magnetic cores 512 a and 512 b. Then, the magnetic flux divides into two directions and is induced to the two magnetic cores 512 a and 512 b embedded in the insulating layer 110 . In this way, magnetic fluxes in opposite directions pass through the first coil portion 515a and the second coil portion 515b. As described above, the winding directions of the first coil part 515a and the second coil part 515b are opposite to each other, and therefore, the voltages induced in the first coil part 515a and the second coil part 515b are in the same direction due to magnetic fluxes in opposite directions. Accordingly, a voltage obtained by adding the voltages induced in the first coil portion 515 a and the second coil portion 515 b is generated in the coil 514 .

In portable electronic devices that are required to be thinner, the upper surface of antenna 500 is arranged to be parallel to the main surface of the portable electronic device. In addition, generally, the main surface of the portable electronic device is used so that it faces the incoming direction of the magnetic flux. That is, the upper surface of the antenna 500 faces the incoming direction of the magnetic flux. The antenna 500 according to the fifth embodiment has a structure for capturing magnetic flux on its upper surface, and therefore has a structure for capturing magnetic flux most efficiently in such a usage mode. Therefore, the antenna 500 contributes to a portable electronic device that is thin and has high antenna sensitivity.

"Sixth Embodiment"

A sixth embodiment of the present invention will be described with reference to FIG. 9 . 9 is a perspective view showing the structure of a magnetic field coupling antenna module according to a sixth embodiment. The same symbols are assigned to the same structures as those in the first embodiment, and explanations thereof are omitted. In the following description, the magnetic field coupling type antenna module is simply referred to as an antenna module.

In FIG. 9 , an antenna module 601 is formed by embedding a magnetic core 112 and a capacitor 680 in an insulating layer 110 . Capacitor 680 is located between the side surface of insulating layer 110 and via 122 when viewed from the outside of coil 114 , that is, the upper surface of insulating layer 110 . The capacitor 680 constitutes a resonant circuit together with the coil 114 . When the resonance frequency of the resonance circuit matches the frequency of the magnetic flux captured by the antenna 600, a particularly large induced voltage can be induced.

In this embodiment, the capacitor 680 and the coil 114 constituting the resonant circuit are integrated to form the antenna module 601 . Therefore, after the manufacture of the antenna 600, the resonance frequency does not fluctuate, and stable and high antenna sensitivity can be realized.

Capacitor 680 and magnetic core 112 are embedded in resin in a semi-cured state (prepreg) in the same process. Therefore, the capacitor 680 can be easily embedded without unnecessary steps.

In addition, the capacitor 680 is buried in the insulating layer 110 as an element. Therefore, by embedding capacitors with different characteristics, the characteristics of the antenna module 601 can be easily changed without changing the shapes and formation locations of the upper surface conductor 116, the lower surface conductor 118, the side surface conductor 120, and the via 122 formed in the insulating layer 110. In addition, by selecting a capacitor having a large capacitance such as a multilayer capacitor as the capacitor 680 , the characteristics of the antenna module 601 can be greatly changed.

(Modification)

A modified example of this embodiment is shown in FIG. 10 . In FIG. 10 , capacitor 680 is located between magnetic core 112 and via 122 when viewed from the inside of coil 114 , that is, the direction of the upper surface of insulating layer 110 . Also in this modified example, the capacitor 680 and the magnetic core 112 are simultaneously embedded in the insulating layer 110 in the same process, so that it can be easily manufactured.

In a modified example, capacitor 680 is surrounded by upper surface conductor 116 , lower surface conductor 118 , and via 122 . The upper surface conductor 116, the lower surface conductor 118, and the via 122 not only constitute the coil 114, but also function as a shield for the capacitor 680, and can reduce the influence of the external electromagnetic field on the capacitor 680. Therefore, in the antenna module 602 , fluctuations in the resonance frequency of the resonance circuit constituted by the coil 114 and the capacitor 680 are further suppressed, and the antenna sensitivity of the antenna module 602 is further stabilized.

In addition, in this embodiment, the capacitor 680 is embedded in the insulating layer 110, but the embedded electronic component may be a component other than a capacitor. In addition, there may be a plurality of capacitors 680 embedded in the insulating layer 110 .

"Seventh Embodiment"

A seventh embodiment of the present invention will be described with reference to FIG. 11 . 11 is a perspective view showing the structure of a magnetic field coupling antenna device according to a seventh embodiment. The same symbols are assigned to the same structures as those in the first embodiment, and explanations thereof are omitted. In the following description, the magnetic field coupling type antenna device is simply referred to as an antenna device.

In FIG. 11 , an antenna device 703 is configured by embedding a magnetic core 112 , a capacitor 780 , and an integrated circuit element 782 in an insulating layer 110 . The integrated circuit element 782 incorporates an RFID processing circuit.

By embedding the integrated circuit element 782 also in the insulating layer 110, all the elements necessary for the antenna 700 including the magnetic core 112 and the coil 114 to function as an RFID antenna are integrated. Therefore, it can be integrally attached to a portable electronic device.

In addition, the magnetic core 112, the coil 114, and the integrated circuit element 782 can be simultaneously embedded in the insulating layer 110 in the same process. Thus, the antenna device 703 is very easily manufactured.

"Eighth Embodiment"

An eighth embodiment of the present invention will be described with reference to FIGS. 12-A and 12-B. 12-A and 12-B are diagrams showing the structure of the magnetic field coupling antenna device according to the eighth embodiment, FIG. 12-A is a perspective view, and FIG. 12-B is a cross-sectional view along the line C-C of FIG. 12-A. The same symbols are assigned to the same structures as those in the first embodiment, and explanations thereof are omitted. In the following description, the magnetic field coupling type antenna device is simply referred to as an antenna device.

In FIGS. 12-A and 12-B , the antenna device 803 is configured by embedding the magnetic core 112 , the capacitor 880 , and the integrated circuit element 882 in the insulating layer 110 . An RFID processing circuit is built in the integrated circuit element 882 . A lower insulating layer 811 is further provided on the lower surface of the insulating layer 110 , and a lower surface electrode layer 890 is formed on the lower surface of the lower insulating layer 811 .

The lower surface of the antenna device 803 is mounted on the motherboard of the portable electronic device. In this embodiment, a lower surface electrode layer 890 is formed on the lower surface of the antenna device 803 . Therefore, the magnetic field of the circuit formed on the motherboard is shielded by the lower surface electrode layer 890, and the antenna device 803 is not affected by the circuit on the motherboard. Therefore, it is possible to suppress fluctuations in the inductance value of the coil 114 constituting the antenna device 803 or the resonance frequency of the resonant circuit constituted by the capacitor 880 and the coil 114 .

(Modification)

Modifications of this embodiment are shown in FIGS. 13-A and 13-B. 13-A and 13-B are diagrams showing modifications of the eighth embodiment, FIG. 13-A is a perspective view, and FIG. 13-B is a cross-sectional view taken along the line D-D of FIG. 13-A.

In FIG. 13-A and FIG. 13-B, in addition to the antenna device 800 described in FIG. 12-A and FIG. Surface electrode layer 892 . The upper surface electrode layer 892 is connected to the lower surface electrode layer 890 via a via 894 . The upper surface electrode layer 892 not only shields the antenna device 800 but also shields the upper surface from being affected by external electromagnetic fields, so that the characteristics of the antenna device 800 are more stable. In addition, the upper surface electrode layer 892 is not limited to the lower surface electrode layer 890, and may be connected to an electrode that is a ground.

In this embodiment, the lower insulating layer 811 and the lower surface electrode layer 890 are formed on the lower surface of the antenna device 803 in which the magnetic core 112 , the capacitor 880 , and the integrated circuit element 882 are embedded in the insulating layer 110 . However, the lower insulating layer 811 and the lower surface electrode layer 890 may also be formed on the lower surface of an antenna module in which only a magnetic core and a capacitor are embedded in the insulating layer 110 . In this case, the antenna module is not affected by the electromagnetic field from the circuit provided on the motherboard, and the inductance value of the coil or the resonance frequency of the resonance circuit composed of the capacitor and the coil can be suppressed from fluctuating.

"Ninth Embodiment"

A ninth embodiment of the present invention will be described with reference to FIG. 14 . 14 is a perspective view showing the structure of a magnetic field coupling antenna device according to a ninth embodiment. The same symbols are assigned to the same structures as those in the first embodiment, and explanations thereof are omitted. In the following description, the magnetic field coupling type antenna device is simply referred to as an antenna device.

In FIG. 14 , in an antenna device 903 , two magnetic cores 912 a and 912 b , a capacitor 980 , and an integrated circuit element 982 are embedded in an insulating layer 110 . The integrated circuit element 982 incorporates an RFID processing circuit.

The coil 914 is divided into a first coil part 915a and a second coil part 915b, and is wound. The first coil part 915 a and the second coil part 915 b each have a coil axis parallel to the upper surface of the insulating layer 110 . Between the first coil part 915a and the second coil part 915b is a non-winding part 970 where no coil is formed. The first coil portion 915a is formed around the magnetic core 912a, and the second coil portion 915b is formed around the magnetic core 912b. The first coil part 915a and the second coil part 915b are connected so as not to cause an induced voltage due to magnetic flux passing through the coil axes of the respective coil parts 915a and 915b in the same direction.

The capacitor 980 and the integrated circuit element 982 are respectively provided between the two magnetic cores 912a and 912b in the non-winding part 970 between the first coil part 915a and the second coil part 915b. The overall miniaturization of the antenna device 903 is achieved by overlapping the non-winding portion 970 for capturing magnetic flux on the upper surface of the insulating layer 110 to function as the coil 914 and the area where the capacitor 980 and the integrated circuit element 982 are installed. In addition, in this embodiment, even if the capacitor 980 or the integrated circuit element 982 exists in the non-wound portion 970 , entry of magnetic flux is not blocked by the capacitor 980 or the integrated circuit element 982 .

In this embodiment, two magnetic cores 912 a and 912 b are buried in the insulating layer 110 . However, it is also possible to bury a magnetic core.

In addition, in the present embodiment, in the antenna device in which the magnetic cores 912a, 912b, the capacitor 980, and the integrated circuit element 982 are buried in the insulating layer 110, a coil is formed between the first coil portion 915a and the second coil portion 915b. Non-winding portion 970 . However, the non-winding portion 970 may also be formed in an antenna module in which only a magnetic core and a capacitor are embedded in the insulating layer 110 . Also in this case, by overlapping the non-winding portion and the capacitor installation area, it is possible to realize a miniaturized antenna module.

Claims (17)

1. a magnetic field coupling type antenna, possesses:

The first insulating barrier;

Be embedded in the magnetic core of described the first insulating barrier;

Be formed at the upper surface conductor of the upper surface of described the first insulating barrier;

Be formed at the lower surface conductor of the lower surface of described the first insulating barrier;

Be formed at the second insulating barrier of the lower surface of described lower surface conductor;

Be formed at the lower surface electrode layer of the lower surface of described the second insulating barrier;

Be electrically connected the bonding conductor of described upper surface conductor and described lower surface conductor,

Wherein, utilize described upper surface conductor, described lower surface conductor and described bonding conductor to form the coil with the coil axes parallel with the upper surface of described the first insulating barrier, described magnetic core is to be mounted in described lower surface conductor side with the overlapping mode of described lower surface conductor.

2. magnetic field coupling type antenna according to claim 1, is characterized in that,

Described magnetic core comprises multiple magnetic cores.

3. magnetic field coupling type antenna according to claim 2, is characterized in that,

The direction that described multiple magnetic core is arranged is the direction orthogonal with the coil axes of described coil.

4. according to the magnetic field coupling type antenna described in any one in claim 1～3, it is characterized in that,

Described in the Area Ratio of the face at least one party's who is arranged in the axial two ends of described coil of described magnetic core face, the area with the orthogonal arbitrary section of described coil axes of magnetic core is large.

5. according to the magnetic field coupling type antenna described in any one in claim 1～3, it is characterized in that,

In the side that is positioned at axial described the first insulating barrier of described coil, described magnetic core is set.

6. according to the magnetic field coupling type antenna described in any one in claim 1～3, it is characterized in that,

Described coil is divided into the first coil portion and the second coil portion and forms to have the state of non-winder in centre.

7. according to the magnetic field coupling type antenna described in any one in claim 1～3, it is characterized in that,

The through hole that utilization is electrically connected with upper surface conductor or/and the lower surface conductor of described the first insulating barrier or path form at least a portion of described bonding conductor.

8. magnetic field coupling type antenna according to claim 7, is characterized in that,

Utilize at least a portion that forms described bonding conductor at the preformed pattern in the side of described magnetic core, described pattern is electrically connected with described through hole or path.

9. a magnetic field coupling type antenna module, is characterized in that, possesses:

Magnetic field coupling type antenna in claim 1～8 described in any one;

The electronic unit of burying underground at described the first insulating barrier.

10. magnetic field coupling type antenna module according to claim 9, is characterized in that,

Described electronic unit is capacitor.

11. according to the magnetic field coupling type antenna module described in claim 9 or 10, it is characterized in that,

Observe from the upper surface direction of described the first insulating barrier, described electronic unit is arranged between described magnetic core and described bonding conductor.

12. 1 kinds of magnetic field coupling type antenna modules, is characterized in that possessing:

Magnetic field coupling type antenna claimed in claim 6;

Be embedded in the capacitor of described the first insulating barrier,

Wherein, described capacitor is arranged at described non-winder.

13. 1 kinds of magnetic field coupling type antenna devices, possess:

Magnetic field coupling type antenna module in claim 9～12 described in any one;

Be embedded in the integrated circuit of described the first insulating barrier.

14. magnetic field coupling type antenna devices according to claim 13, is characterized in that,

The position that does not form described upper surface conductor at the upper surface of described the first insulating barrier is formed with upper surface electrode layer.

The manufacture method of 15. 1 kinds of magnetic field coupling type antennas, comprising:

On the second insulating barrier, form the operation of lower surface conductor;

The operation of carrying magnetic core on described the second insulating barrier;

To described the second insulating barrier and described magnetic core, the first insulating barrier of the semi-harden state that pressurizes, and described magnetic core is embedded in to the operation of described the first insulating barrier;

Make the operation of described the first insulating barrier sclerosis that is embedded with described magnetic core;

Form the operation of the bonding conductor being electrically connected with described lower surface conductor at described the first insulating barrier;

On opposed of the face joining with described lower surface conductor of described the first insulating barrier, form the operation of the upper surface conductor being electrically connected with described bonding conductor,

By described magnetic core to be mounted in described lower surface conductor side with the overlapping mode of described lower surface conductor.

The manufacture method of 16. 1 kinds of magnetic field coupling type antenna modules, comprising:

On the second insulating barrier, form the operation of lower surface conductor;

The operation of carrying magnetic core and capacitor on described the second insulating barrier;

To described the second insulating barrier and described magnetic core and described capacitor, the first insulating barrier of the semi-harden state that pressurizes, and described magnetic core is embedded in to the operation of described the first insulating barrier;

Make the operation of described the first insulating barrier sclerosis that is embedded with described magnetic core and described capacitor;

Form the operation of the bonding conductor being electrically connected with described lower surface conductor at described the first insulating barrier;

On opposed of the face joining with described lower surface conductor of described the first insulating barrier, form the operation of the upper surface conductor being electrically connected with described bonding conductor,

By described magnetic core to be mounted in described lower surface conductor side with the overlapping mode of described lower surface conductor.

The manufacture method of 17. 1 kinds of magnetic field coupling type antenna devices, comprising:

On the second insulating barrier, form the operation of lower surface conductor;

The operation of carrying magnetic core, capacitor and integrated circuit component on described the second insulating barrier;

To described the second insulating barrier and described magnetic core, described capacitor and described integrated circuit component, the first insulating barrier of the semi-harden state that pressurizes, and described magnetic core is embedded in to the operation of described the first insulating barrier;

Make the operation of described the first insulating barrier sclerosis that is embedded with described magnetic core, described capacitor and described integrated circuit component;

Form the operation of the bonding conductor being electrically connected with described lower surface conductor at described the first insulating barrier;

On opposed of the face joining with described lower surface conductor of described the first insulating barrier, form the operation of the upper surface conductor being electrically connected with described bonding conductor,

By described magnetic core to be mounted in described lower surface conductor side with the overlapping mode of described lower surface conductor.

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