JP5412594B1 - Antenna module, antenna module precursor, and method of manufacturing the antenna module - Google Patents

Abstract

A compact, thin and high-performance antenna module is manufactured with high productivity that reflects the effects of electromagnetic changes and shape changes caused by relatively reducing the equivalent diameter of an antenna pattern.
An antenna assembly having an antenna pattern in which antenna coils made of conductive wires having a rectangular cross section with respect to an antenna substrate are arranged in a spiral shape is divided into a lattice shape through a double-sided adhesive layer. When joining to a magnetic sheet in which a large number of small pieces are assembled in a planar shape, the antenna coil and the magnetic sheet laminate are combined with the antenna coil facing the magnetic sheet side. Next, the combined antenna module precursor is pressed in the thickness direction through a cushioning material to obtain a target antenna module.
[Selection] Figure 8

Description

  The present invention relates to an antenna module, an antenna module precursor, and a method for manufacturing the antenna module.

  Conventionally, an antenna module is used for an electronic solid-state identification system (RFID) of a high-function portable information terminal, a non-contact IC card, a near field communication device (NFC), etc. (hereinafter collectively referred to as a “portable information terminal”). Has been. A conventional antenna module is disclosed in, for example, Japanese Patent Application Laid-Open No. 2011-212337.

  This antenna module basically includes an antenna coil (first element), a sintered ferrite sheet (second element) and a metal foil (third element) in which a large number of small pieces divided into random shapes are assembled in a planar shape. The three elements are stacked. When the antenna module is mounted on a portable information terminal, it is supposed to exhibit a corresponding magnetic permeability in a predetermined frequency region.

JP 2011-2111337 A

  In recent years, as portable information terminals have been downsized to a palm size and become more sophisticated, the types of antenna modules have been forced to be further reduced in size, thickness, and performance.

  Therefore, the present inventors tried to manufacture an antenna module smaller than the conventional antenna module in order to put into practical use an antenna module having a minimum width of about 5 to 25 mm in a small portable information terminal according to a known technique. As a result, the following performance and problems in the manufacturing process were encountered.

  The problem relating to the performance of the small antenna module is caused by the fact that the equivalent diameter of the spiral coil pattern in the antenna coil becomes smaller as the antenna module becomes smaller. For example, in the case of a coil pattern in which a predetermined length of antenna conductive wire is spirally wound on a plane, the outermost loop diameter is relatively small. As the equivalent diameter of the antenna coil becomes relatively small, an electromagnetic change occurs, and there is a problem that a parameter indicating antenna characteristics, an L value (inductance value), and a Q value (Quality factor) are lowered. In addition, in an environment where the metal material of an electronic component such as a battery pack is used in the vicinity where the antenna is present, the influence on the electromagnetic wave characteristics increases as the distance between the metal material and the antenna coil decreases. In particular, there is a problem that the Q value is significantly reduced.

  The problem in the manufacturing process is that, as described above, an antenna module is composed of three elements, namely an antenna coil, a sintered ferrite sheet, and a metal foil. An efficient process has not been established for integration. Further, not only the productivity of the antenna module is significantly different depending on the manufacturing process, but also the electromagnetic wave characteristics of the antenna module are significantly different due to the difference of the process and appear in the portable information terminal.

  Therefore, the present inventors manufacture a small, thin and high-performance antenna module with high productivity against the effects of electromagnetic change and shape change due to the relatively small equivalent diameter of the antenna coil. For this purpose, I studied earnestly. As a result, a fact that a sintered ferrite sheet having a specific structure is prepared, and an antenna substrate on which an antenna coil is arranged is bonded to the sintered ferrite sheet (magnetic sheet) in a specific form. The present invention has been completed.

  An object of the present invention is to provide a small, thin and high-performance antenna module and a manufacturing method with high productivity.

An antenna module according to an embodiment of the present invention includes:
A magnetic sheet for focusing the magnetic flux;
A double-sided adhesive layer bonded to the top surface of the magnetic sheet;
An antenna coil having a conductor portion and a gap portion of a predetermined coil pattern laminated on the double-sided adhesive layer;
An antenna substrate laminated on the antenna coil,
The double-sided adhesive layer is crushed and deformed between the antenna coil and the magnetic sheet, and at least a part of the double-sided adhesive layer bulges in the gap portion of the antenna coil. .

  In the present invention, the double-sided adhesive layer is pressed downward by the antenna coil, and a part of the adhesive layer is pushed outward from between the antenna coil and the magnetic sheet, whereby the space between the antenna substrate and the magnetic sheet is obtained. The means for inflating the double-sided adhesive layer existing in the above is employed. By adopting this means, the double-sided adhesive layer that existed between the antenna coil and the magnetic sheet is pushed outward and the distance between the two becomes infinitely small. The antenna coil is as close as possible to the direct attachment structure, and the decrease in the L value and the Q value is suppressed. In other words, the reduction in antenna characteristics due to the reduction in the equivalent diameter of the antenna coil is supplemented.

  In the structure of the antenna module, the antenna coil and the magnetic sheet are directly opposed to each other without interposing an antenna base material between them, and it is ideal to directly attach the antenna coil to the magnetic sheet. is there. The present invention achieves a structure that approximates this ideal structure. As a result, the magnetic sheet more effectively focuses the magnetic flux generated around the antenna. Then, the L value and Q value of the antenna are relatively improved even in a so-called metal environment where the antenna is used in an environment where a metal material is present. Therefore, the antenna module according to the present invention exhibits higher noise resistance than a known antenna module.

  Then, by bringing the antenna coil close to the surface of the magnetic sheet so that the distance t2 between the antenna coil and the magnetic sheet is about 0.1 to about 30 μm, preferably about 0.1 to about 5 μm, an L value is obtained. And Q value can be improved effectively. That is, by setting the distance t2 to about 0.1 μm or more, a sufficient thickness of the double-sided adhesive interposed between the antenna coil and the magnetic sheet is ensured so that the double-sided adhesive layer has a stable adhesive force. it can. Further, by setting the distance t2 to about 30 μm or less, the magnetic flux generated around the antenna coil can be remarkably focused. In particular, when the distance t2 is 5 μm or less, it is possible to expect a significant noise reduction. However, the present invention is not limited to the above numerical range.

  Further, in the present invention, the double-sided adhesive layer extended between the antenna coil and the magnetic sheet (extruded outward) has the double-sided adhesive layer positioned between the antenna coil and the magnetic sheet facing upward. Inflate to increase the contact area between the antenna coil and the double-sided adhesive layer. That is, since the double-sided adhesive layer is bonded not only to the lower surface of the conductor portion of the antenna coil but also to the side surfaces, the adhesion between the two is improved.

  In the antenna module according to another embodiment of the present invention, a spacer material having a predetermined thickness is disposed in the non-antenna pattern region (A) inside the innermost loop of the antenna coil, and the non-antenna pattern region (A) A part of the double-sided adhesive layer and the spacer material are bonded together. Alternatively, a spacer material having a predetermined thickness is disposed in an outer margin region (C) of the outermost loop of the antenna coil, and a part of the double-sided adhesive material layer and the spacer material are disposed in the margin region (C). Are connected. A first spacer material having a predetermined thickness is disposed in the inner non-antenna pattern area (A) of the innermost loop of the antenna coil, and the outer margin area of the outermost loop of the antenna coil. A second spacer material having a predetermined thickness is disposed in (C), and a part of the double-sided adhesive material layer and the first and first adhesive layers in both the non-antenna pattern region (A) and the margin region (C). Two spacer materials are combined with each other.

  That is, by forming the spacer material on the double-sided adhesive layer so as to overlap the area other than the antenna pattern area, the thickness of the antenna pattern area and the area other than the antenna pattern area can be increased while maintaining the state where the antenna coil is close to the direct attachment. It becomes uniform. In other words, the spacer material is disposed on the inner side and / or the outer side of the antenna pattern region in order to correct the thickness difference of the antenna conductor. The spacer material is preferably made of a double-sided adhesive material. Therefore, the antenna base material can be kept in a more flat state by the spacer material. Therefore, it can adhere more reliably to a plane such as a casing to which the antenna is attached. Furthermore, the spacer material reduces the gap where there is no double-sided adhesive layer or the like in the gap portion of the antenna coil, or the gap can be substantially eliminated, so that the strength of the entire antenna module is improved. .

  In the antenna module according to another embodiment of the present invention, the magnetic sheet includes a ferrite protective film, an adhesive layer disposed on the ferrite protective film, and a plurality of sintered ferrite pieces bonded to the upper surface of the adhesive layer. And a sintered magnetic material layer in which is assembled. Preferably, the ferrite protective film is a peeling protective film.

  The peeling protective film means a protective material used to protect the antenna module in the distribution process from the manufacturing process to the incorporation of the antenna module into the portable information terminal. Therefore, when the antenna module is incorporated into the portable information terminal, the protective film is peeled off to expose the adhesive layer, so that the protective film exhibits a function of a so-called “separator film”. That is, the protective film mentioned above can also be called a separator film. Therefore, once the antenna module according to the present invention is incorporated into a portable information terminal, there is no protective film. Similarly, there is no protective film in the antenna module in a directly connected manufacturing process that does not require a distribution process in the process of manufacturing the antenna module and the process of assembling the portable information terminal.

  In the antenna module according to another embodiment of the present invention, the magnetic sheet is adhered to a flexible conductive metal foil, an adhesive layer disposed on the flexible conductive metal foil, and an upper surface of the adhesive layer. And a sintered magnetic layer in which a plurality of small pieces are gathered.

  That is, the flexible conductive metal foil is similar to the known technology in that the antenna module is a metal in an environment where a metal packaged together with an electronic component using a battery pack or other metal material in a portable information terminal is close. The influence of the eddy current generated by is suppressed to a predetermined range. In the present invention, a flexible conductive metal foil having an adhesive applied to at least one surface is prepared as the conductive metal foil, and this is applied to a magnetic sheet instead of a ferrite protective film in the process of manufacturing sintered ferrite. Adopt the technical idea of wearing. Thereby, when manufacturing the antenna module which finally has flexible conductive metal foil, the process of attaching a protective film separately to a magnetic sheet, the process of peeling off the attached protective film, etc. can be omitted.

  In the antenna module according to another embodiment of the present invention, the antenna base material includes a base material layer on which the antenna coil is formed on a lower surface, and an adhesive layer formed on the upper surface of the base material layer. A release sheet is attached to the upper surface of the material layer.

  That is, because the release sheet is attached to the upper surface of the antenna substrate, the release sheet is peeled to expose the adhesive layer, and the antenna substrate surface is attached to the target surface. An antenna module can be easily incorporated.

A method for manufacturing an antenna module according to an embodiment of the present invention includes:
Preparing a magnetic sheet for focusing magnetic flux;
Depositing a double-sided adhesive layer on the magnetic sheet;
A step of forming an antenna module precursor by laminating an antenna assembly including an antenna coil having a conductor portion and a gap portion of a predetermined coil pattern, and an antenna base material coupled to the antenna coil on the double-sided adhesive layer. When,
Pressing the antenna module precursor in the stacking direction via a cushioning material.

  By adopting this manufacturing method, the double-sided adhesive material layer is attached to the magnetic sheet side having a flat plane, so that the two are substantially in surface contact and joined. Further, the obtained antenna module precursor is pressed (or pressed) from the front and back surfaces to the inside of the antenna module through a cushioning material so that the double-sided adhesive layer is between the antenna coil lower surface and the magnetic sheet upper surface. It is crushed. And a double-sided adhesive material layer deform | transforms fluidly using the difference in the planar height level of the conducting wire part of an antenna coil, and other parts (a clearance part and a non-antenna pattern area | region). That is, a part of the double-sided adhesive material layer in contact with the conductor portion of the antenna coil is rolled, and the rolled volume is bulged upward in the gap portion of the antenna coil. As a result, the substantial thickness of the double-sided adhesive layer between the antenna coil (conductor portion) and the magnetic sheet is reduced, and the two elements of the antenna coil and the magnetic sheet are infinitely close to each other.

  In some embodiments, the equivalent width (d1) of the antenna pattern region of the spiral coil pattern of the antenna coil and the equivalent width of the non-antenna pattern region surrounded by the antenna coil disposed on the magnetic sheet ( The ratio (d1 / d2 = β) to d2) is preferably in the range of 0.2 to 1.5. The equivalent width (d1) of the antenna pattern region means the distance between the outer edge of the outermost loop and the inner edge of the innermost loop in the coil pattern. That is, in the antenna module for the purpose of downsizing as in the present invention, the equivalent width (d1) of the antenna pattern region is relatively narrow. By setting the ratio β (d1 / d2) to 0.2 to 1.5, the performance and size of the antenna module can be optimized.

  In the present specification, as described in the drawings, “upper” is defined as the antenna substrate side, and “lower” is defined as the magnetic sheet side. These “upper” and “lower” notations merely indicate the relative positional relationship of the structure for the purpose of explaining the present invention, and do not limit the present invention. For example, the fact that the antenna coil is formed on the lower surface of the antenna base means that there is no antenna base between the antenna coil and the magnetic sheet. When the antenna module is mounted on the portable information terminal so that the magnetic sheet is positioned above the antenna base material, the antenna coil is naturally formed on the upper surface of the antenna base material.

  The present invention provides a small, thin and high-performance antenna module to cope with the effects of electromagnetic changes and shape changes caused by making the equivalent diameter of the antenna coil relatively smaller than that of known antenna modules, And the effect that the method of manufacturing the said antenna module with high productivity can be provided is exhibited.

The disassembled perspective view of the antenna module which concerns on one Embodiment of this invention. It is a perspective view of the magnetic sheet of the antenna module of FIG. 1, (a) is the state which affixed the protective film for peeling, (b) shows the state which peeled the protective film for peeling. The perspective view of the antenna assembly of the antenna module of FIG. FIG. 4 is a plan view of the antenna assembly of FIG. 3. The top view of the antenna assembly of the modification of FIG. The perspective view of the precursor of the antenna module of FIG. Sectional drawing of the antenna module precursor of FIG. Sectional drawing of the antenna module of FIG. FIG. 9 is a cross-sectional SEM image of the antenna module of FIG. 8. The perspective view which shows the green ferrite sheet of 1 process of manufacturing the antenna module of one Embodiment of this invention. The perspective view which shows the process of joining a film to the front and back of a sintered ferrite sheet | seat in 1 process of manufacturing the antenna module of one Embodiment of this invention. The perspective view which shows the process of joining a magnetic sheet laminated body and an antenna assembly in one process of manufacturing the antenna module of one Embodiment of this invention in order to form an antenna module precursor. Sectional drawing which shows the process of pressing an antenna assembly precursor in 1 process of manufacturing the antenna module of one Embodiment of this invention. The SEM image of the antenna module of a comparative example. The graph which shows the relationship between the distance and the Q value between the antenna and metal material in the Example and comparative example which concern on this embodiment. The graph which shows the relationship between the distance between the antenna and metal material in Example and a comparative example which concern on this invention, and an inductance (L value). The disassembled perspective view of the antenna module of 2nd Embodiment of this invention. FIG. 18 is a cross-sectional view of the antenna module of FIG. 17. The disassembled perspective view of the antenna module which concerns on the modification of 2nd Embodiment of this invention. FIG. 20 is a cross-sectional view of the antenna module of FIG. 19.

  Hereinafter, an embodiment of an antenna module (antenna device) of the present invention will be described with reference to the drawings. In addition, the shape of each figure referred in the following description is a conceptual diagram or a schematic diagram for explaining a suitable shape dimension, and a dimension ratio etc. do not necessarily correspond with an actual dimension ratio. That is, the present invention is not limited to the dimensional ratio in the drawings.

(First embodiment)
FIG. 1 is an exploded perspective view of the antenna module (antenna device) 10. The structure of the antenna module 10 of one embodiment of the present invention will be described in detail.

  As shown in FIG. 1, the antenna module 10 includes a planar magnetic sheet 110 for focusing magnetic flux, a double-sided adhesive layer 120 deposited on the magnetic sheet 110, and a double-sided adhesive layer 120 deposited on the double-sided adhesive layer 120. A planar antenna coil 130 having a spiral coil pattern, and a planar antenna substrate (protective layer) 140 deposited on the antenna conductor 130 to protect the antenna conductor 130. . In other words, the antenna module 10 is an assembly of the magnetic sheet laminate 11 in which the magnetic sheet 110 and the double-sided adhesive layer 120 are laminated, and the antenna assembly 12 in which the antenna coil 130 and the antenna substrate 140 are integrally formed. is there. Hereinafter, each component which comprises the antenna module 10 of this embodiment is demonstrated in detail.

(Magnetic sheet laminate)
As shown in FIG. 2, the magnetic sheet laminate 11 is a laminate in which a double-sided adhesive layer 120 is formed on a magnetic sheet 110. A peeling protective film 125 is selectively attached to the upper surface of the double-sided adhesive layer 120 (see FIG. 2A).

(Magnetic sheet)
The magnetic sheet 110 of the antenna module 10 according to this embodiment will be described. The magnetic sheet 110 is bonded to the sintered magnetic layer 111, the adhesive layer 112 formed on the lower surface of the sintered magnetic layer 111, and the adhesive layer 112 (can be selectively peeled off). It consists of a ferrite protective film 113 for peeling. The sintered magnetic layer 111 is made of a sintered ferrite sheet having a predetermined shape obtained by firing a green ferrite sheet, preferably a planar assembly of a plurality of ferrite sintered body small pieces 111a arranged in parallel in the vertical and horizontal directions. These adjacent small pieces 111a are in close contact with each other, and as a result, there is substantially no gap. The sintered magnetic layer 111 (or the magnetic sheet 110) has a flat surface with substantially no step on the upper surface and the lower surface thereof. The vertical and horizontal widths of these small pieces 111a are preferably about 0.3 to 3.0 mm (2.0 mm in the present embodiment), so that when the magnetic sheet 110 is deformed, the small pieces 111a bend between the small pieces 111a. As a whole, it becomes a curved surface. Preferably, the sintered magnetic layer 111 is selected from Ni—Zn—Cu-based materials, the real part μr ′ of the magnetic permeability of the sintered magnetic layer 111 is 70 or more, and the imaginary number of the magnetic permeability. The part μr ″ is 15 or less. By selecting the material, the magnetic flux in the antenna module 10 can be effectively focused and the communication characteristics can be improved.

  In this embodiment, the peeling protective film 113 made of polyethylene terephthalate is used, but instead of the protective film, a conductive metal foil (shield layer) made of aluminum or the like can be used.

  In some embodiments, instead of dividing the sintered magnetic layer into a plurality of small pieces, one or both sides of the sintered magnetic layer are half-cut in the thickness direction as shown in FIGS. May be provided. In this case, the distance between the dividing grooves corresponds to the width of the small piece. In some embodiments, the sintered magnetic layer may be formed of small pieces arranged in an irregular shape (formed without forming the dividing grooves described later).

(Double-sided adhesive layer)
The double-sided adhesive layer 120 of the antenna module 10 according to this embodiment will be described (see FIG. 1). The double-sided adhesive layer 120 joins the magnetic sheet 110 and the antenna coil 130 to form the antenna module precursor 13 described later. The double-sided adhesive layer 120 is made of a semi-gel pressure-sensitive adhesive in which a softening agent, an adhesive, a tackifier, or the like is added to a synthetic resin such as polyacrylate or polyvinyl chloride, or synthetic rubber. Become. Preferably, the thickness of this double-sided adhesive layer 120 is 5 μm to 30 μm. The thickness of the double-sided adhesive layer 120 can reduce the distance t2 between the antenna coil 130 and the magnetic sheet 110 as much as possible while having sufficient adhesive force when crushed by a pressing means described later. As such, it is preferably optimized. In this example, a 10 μm-thick pressure-sensitive double-sided adhesive layer 120 having a polyacrylic acid ester as a main component and a softening agent, a pressure-sensitive adhesive, a viscosity agent and the like as auxiliary components was prepared.

  And in the manufacturing process stage before joining the magnetic sheet 110 and the antenna coil 130, the double-sided adhesive material layer 120 is a protective film for peeling made of synthetic resin such as polyethylene, polypropylene, polyethylene terephthalate on at least one side, preferably both sides. 125 is affixed and configured in a roll shape or a sheet shape (see FIG. 2A). When making this double-sided adhesive material layer 120 into a roll shape, the protective film 125 for peeling should just be affixed only on the single side | surface.

(Antenna assembly)
As shown in FIG. 3, the antenna assembly (or antenna laminate) 12 is an antenna laminate in which an antenna coil 130 is formed on one surface of an antenna substrate 140. A release sheet 143 is selectively attached to the upper surface of the antenna assembly 12.

(Antenna coil)
The antenna coil 130 of the antenna module 10 according to the present embodiment will be described. As shown in FIG. 4, the antenna coil 130 is provided on the conductive wire portion 131 having a spiral coil pattern, a gap portion 132 formed between adjacent wires of the conductive wire portion 131, and both ends of the conductive wire portion 131. A pair of antenna connection pads 133a and 133b. In the antenna assembly 12, a region where the inner conductor 131 of the innermost loop c1 of the antenna coil 130 does not exist is defined as a non-antenna pattern region A. Further, an area where the conductor 131 and the gap 132 of the antenna coil 130 are disposed is defined as an antenna pattern area B. Then, a region where the outer conductor 131 of the outermost loop c2 of the antenna coil 130 does not exist is defined as a margin region C. That is, the non-antenna pattern area A, the antenna pattern area B, and the margin area C are arranged adjacent to each other from the inside to the outside of the antenna coil 130.

  The conductor 131 of the antenna coil 130 has a length necessary for inducing driving power of the antenna module 10 in a portable information terminal mounted as the antenna module 10 described later. As described above, the antenna substrate 140 according to the present embodiment is formed smaller than that according to the known technology. Therefore, although it is somewhat influenced by the size of the cross section of the antenna coil 130, the number of spiral coil patterns in the antenna coil 130 according to the present embodiment is generally larger than that of the antenna coil according to the known technology. Become more. As a result, the area occupied by the coil pattern (antenna pattern area B) with respect to the entire area on the antenna substrate 140 is relatively larger than that of a known general antenna module.

  An antenna pattern area ratio can be considered as a parameter representing the degree of miniaturization of the antenna assembly 12. Specifically, the surface of the antenna assembly 12 of this embodiment (represented below the antenna substrate 140 in the following drawings) is divided into four trapezoidal segmented antenna pattern regions b1, The antenna pattern area B is a sum of b2, b3, and b4, a non-antenna pattern area A surrounded by the antenna pattern area B, and a margin area C where the antenna pattern area B is surrounded.

Therefore, in the present embodiment, when the antenna pattern region B / non-antenna pattern region A is defined as an antenna pattern region ratio α, the antenna pattern region ratio α is larger than that of a known antenna in the antenna according to the present embodiment. In the antenna module in which this embodiment is incorporated in a palm-sized small portable information terminal, the length of the conductor of the antenna coil 130 is not significantly different from that of a non-small portable terminal. It will increase.

In addition, the antenna assembly 12 includes those having a substantially square shape and those having a rectangular shape having a short side width (short width) D and a longer side width L as shown in FIG. Therefore, even if the antenna pattern area ratio α is uniformly applied to the two antennas to express the degree of miniaturization, it is difficult to intuitively grasp the antenna pattern area ratio α. Therefore, the degree of miniaturization of the antenna is expressed using a parameter based on the equivalent width (length corresponding to the height of the trapezoid) of the four segment antenna pattern regions b1, b2, b3, and b4. The “equivalent width” means a distance d1 between the outer edge of the outermost peripheral loop c1 and the inner edge of the innermost peripheral loop c2 in the coil pattern.

That is, the size of the antenna is reduced by the ratio of the non-antenna pattern region A to the short width d2 (the ratio β of the short width ratio d1 / d2) to the equivalent width d1 of the segmented antenna pattern regions b1, b2, b3, b4. Express. By expressing as such, it is easy to understand the bonding action of the adhesive layer that bonds the antenna to the sintered ceramic sheet.

  In the antenna substrate 140 according to the present invention in which the short width D is in the range of 5 to 25 mm, the short width ratio β which is the ratio of the short width d2 of the non-antenna pattern region A to the equivalent width d1 of the segmented antenna pattern region is 0. It is preferable that it is 2-1.5. More preferably, the short width ratio β is 0.3 to 0.7. And the antenna coil 130 is integrated in a portable information terminal as a coil pattern patterned spirally with the short width ratio β.

An antenna assembly (an integrated structure of the antenna coil 130 and the antenna substrate 140) having such a shape and structure is formed by photolithography on the surface (lower surface) of the antenna substrate 140 (substrate layer 141) as a known method. The antenna coil 130 is formed by using a method, a pattern printing method, an etching method, or the like. The antenna coil 130 has a coil pattern in which the conductor 131 is preferably wound four or more times. One end 131a of the antenna coil 130 is electrically connected to the antenna connection pad 133a provided in the margin region C, and the other end 131b is electrically connected to the other antenna connection pad 133b across the coil pattern or under the coil pattern. That is, both ends 131a and 131b of the conductor 131 can be energized with the electronic circuit of the portable information terminal via the antenna connection pads 133a and 133b. Although the antenna module 10 of the present embodiment is reduced in size, the antenna module 10 includes an antenna coil 130 having a predetermined length necessary for inducing a predetermined driving power as in the case of a large antenna module. Therefore, the number of turns of the coil pattern is relatively larger than that of the known technique, and is 4 to 10, preferably 5 to 7.

  The conductive wire portion 131 of the antenna coil 130 is formed by arranging conductive metal wires such as copper, aluminum, silver, and gold in a spiral shape, and has a square cross section, preferably a trapezoid. In particular, the lateral width d4 is 100 to 800 μm, the thickness d3 (see FIG. 7 described later) is 10 to 50 μm (35 μm in this embodiment), and the ratio of the thickness d3 to the lateral width d4 (d3 / d4) is It is in the range of 0.01 to 0.5, preferably 0.05 to 0.3. Note that the corners of the rectangular or trapezoidal cross section may be chamfered somewhat in an arc shape for reasons that cannot be avoided in the manufacturing process or for design reasons.

(Antenna substrate)
As shown in FIG. 3, the antenna substrate 140 includes a substrate layer 141 having an antenna coil 130 formed on the lower surface and an adhesive layer 142 formed on the upper surface. The base material layer 141 (or the antenna base material 140) is made of a heat-resistant synthetic resin whose planar shape is substantially square or rectangular, for example, polyimide, polyethersulfone, polyetheretherketone, polyetherimide, etc. A sheet or film having a thickness of ˜50 μm, preferably 5 to 15 μm. In addition, a release sheet (or film) 143 is selectively attached to the upper surface of the antenna base 140 of the antenna assembly 12 via an adhesive layer 142. By peeling off the release sheet 143, the upper surface of the antenna module 10 can be attached to a desired target via the adhesive layer 142.

(Antenna module precursor)
6 and 7 are a perspective view and a sectional view of the antenna module precursor 13. The antenna module precursor 13 is obtained by sequentially stacking the magnetic sheet 110, the double-sided adhesive layer 120, the antenna coil 130, and the antenna base material 140 described above. In the antenna precursor 13, a cavity S is formed in the gap 132, the non-antenna pattern region A, and the margin region C of the antenna coil 130 between the double-sided adhesive layer 120 and the antenna substrate 140. Only the lower surface of the conductor 131 of the antenna coil 130 is bonded to the upper surface of the double-sided adhesive layer 120. In other words, in such a state, the antenna assembly 12 and the magnetic sheet laminate 11 are joined only by a part of the double-sided adhesive layer 120 interposed between the antenna coil 130 and the sintered magnetic layer 111. . Therefore, it cannot be said that the bonding force between the magnetic sheet laminate 11 and the antenna assembly 12 is sufficient. The lower surface of the conductor 131 of the antenna coil 130 and the upper surface of the sintered magnetic layer 111 are separated by a distance t1. The distance t1 is substantially the same as the width of the double-sided adhesive layer 120. That is, in this embodiment, t1 is about 10 μm.

(Antenna module)
The antenna module 10 is formed by pressing the antenna module precursor 13 with a predetermined load. As shown in FIG. 8, the antenna module 10 is laminated on the magnetic sheet 110 for focusing the magnetic flux, the double-sided adhesive layer 120 bonded to the upper surface of the magnetic sheet 110, and the double-sided adhesive layer 120. An antenna coil 130 and an antenna substrate 140 stacked on the antenna coil 130 are provided. Then, the double-sided adhesive layer 120 is crushed and deformed between the antenna coil 130 and the magnetic sheet 110, and a part of the double-sided adhesive layer 120 bulges at least in the gap 132 of the antenna coil 130. In other words, the double-sided adhesive layer 120 is formed with a crushed portion 121 rolled into the conducting wire portion 131 and a bulging portion 122 raised in the gap portion 132. And the upper surface of the bulging part 122 of the said double-sided adhesive material layer 120 and the lower surface of the antenna base material 140 (base material layer 141) are couple | bonded. Moreover, the side part of the conducting wire part 131 of the antenna coil 130 and the side part of the bulging part 122 of the double-sided adhesive layer 120 are partially coupled.

  A distance t2 between the lower surface of the conductive wire portion 131 and the upper surface of the sintered magnetic layer 111 of the antenna coil 130 is substantially the same as the thickness of the crushing portion 121. The distance t2 is about 5 μm. That is, in the antenna module 10 of the present embodiment, the distance between the lower surface of the antenna coil 130 and the upper surface of the magnetic sheet 110 is reduced to about ½ (t2 / t1) as compared with the antenna module precursor 13. The smaller the value of the compression ratio (t2 / t1), the closer the antenna coil 130 and the magnetic sheet 110 are, and the antenna performance can be improved. In the non-antenna pattern area A and the outer margin area C, which are areas where the conductor 131 of the antenna coil 130 does not exist, the antenna base 140 itself is recessed and curved toward the magnetic sheet 110 side.

  The distance t2 between the antenna coil 130 and the magnetic sheet 110 is preferably about 0.1 to about 5 μm. The closer the antenna coil 130 is to the surface of the magnetic sheet 110, the more effectively the L value and Q value can be improved. Then, by setting the distance t2 to be about 0.1 μm or more, the double-sided adhesive 120 having a thickness sufficient for the double-sided adhesive 120 to exhibit a stable adhesive force is interposed between the antenna coil 130 and the magnetic sheet 110. Can intervene. Further, when the distance t2 is about 5 μm or less, it is possible to expect a significant noise reduction. The distance t2 and / or the compression ratio (t2 / t1) can be adjusted by adjusting the thickness and volume of the double-sided adhesive layer 120 and / or adjusting the pressing load of the antenna module precursor 13 described later. It can be optimized to the desired value.

  FIG. 9 is an SEM image showing a cross section of the antenna module 10. The SEM image was taken at a magnification of 150 times. In the SEM image antenna module 10, a flexible conductive metal foil 114 is employed instead of the ferrite protective film 113. In addition, in the antenna module 10 of one Embodiment of this invention, although the preferable numerical ranges, such as a dimension of each component, were shown, these are only the illustrations for implementing this invention. That is, as will be apparent to those skilled in the art, these numerical ranges are not intended to limit the technical scope or spirit of the present invention.

(Method for manufacturing antenna module)
In the manufacturing method of the antenna module 10 of this embodiment, the magnetic sheet 110 for focusing the magnetic flux is prepared, and the double-sided adhesive layer 120 is deposited on the magnetic sheet 110 to form the magnetic sheet laminate 11. Step S2 for forming the antenna assembly 12 by forming the antenna coil 130 having the conductor 131 and the gap 132 having a predetermined coil pattern on the antenna base 140, and laminating the antenna assembly 12 on the magnetic sheet. Step S4 for laminating (adhering) on the double-sided adhesive layer 120 of the body 11 to form the antenna module precursor 13, and Step S5 for pressing the antenna module precursor 13 through the buffer material T in the laminating direction. Including. Hereinafter, each step will be described in detail.

  In order to manufacture the magnetic sheet 110, as shown in FIG. 10, first, a green ferrite sheet 111 ′ having V-shaped or U-shaped dividing grooves 111b arranged in a lattice shape on the surface (lower side) is provided. prepare.

  Next, the green ferrite sheet 111 ′ is fired to obtain a sintered ferrite sheet 111 ″. Preferably, the sintered ferrite sheet 111 ″ has a real part μr ′ of permeability of 70 or more and an imaginary part μr ″ of permeability. Is an Ni—Zn—Cu-based alloy of 15 or less. Subsequently, as shown in FIG. 11, an adhesive layer 112 is formed on one surface (lower surface) of the obtained sintered ferrite sheet 111 ″. Then, a ferrite protective film 113 (or optionally a flexible conductive metal foil 114) is attached via the adhesive layer 112. In addition, a pressure-sensitive double-sided adhesive layer 120 is laminated on the other surface (upper surface) of the sintered ferrite sheet 111 ″. Then, a peeling protective film 125 is selectively attached to the upper surface of the double-sided adhesive layer 120. Next, they are continuously bent twice into a three-dimensional curved surface or a two-dimensional curved surface having different directions to divide the sintered ferrite sheet 111 ″ along the dividing groove 111b. Thus, the magnetic sheet 110 having the sintered magnetic layer 111 in which the small pieces 111a of the sintered ferrite bodies are gathered in a planar shape (or scale shape) is formed. As a result, the magnetic sheet laminate 11 with the peeling protective film 125 attached thereto is obtained.

  In this way, the magnetic sheet laminate 11 is prepared in which the ferrite protective film 113 is attached via the adhesive layer 112 and the peeling protective film 14 is attached via the pressure-sensitive double-sided adhesive layer 120. After that, the peeling protective film 125 (separator) attached to the upper surface of the double-sided adhesive layer 120 is peeled off. That is, the magnetic sheet laminate 11 in which the magnetic sheet 110 and the double-sided adhesive layer 120 are sequentially laminated is prepared by exposing the double-sided adhesive layer 120.

  Next, as shown in FIG. 12, the conductor coil portion 131 and the connection pad 133 of the antenna coil 130 are formed on the surface of the antenna base 140 by a photolithography method, a pattern printing method, an etching method, or the like. The antenna assembly 12 in which the antenna substrate 140 is integrated is prepared.

  And the magnetic sheet laminated body 11 and the antenna assembly 12 are united | stacked up and down so that the antenna coil 130 may face this magnetic sheet 110 side. As a result, as shown in FIGS. 6 and 7, the antenna module precursor 13 composed of the antenna assembly 12 and the magnetic sheet laminate 11 is obtained via the double-sided adhesive layer 120.

  Subsequently, as shown in FIG. 13, the antenna module precursor 13 is pressed (pressed) with a predetermined load inwardly of the antenna module precursor 13 through the buffer material T on the front and back surfaces thereof. More specifically, as shown in FIG. 13A, the antenna module precursor 13 is placed on the base P1 covered with a silicone rubber sheet having a thickness of 1 mm as the buffer material T to cover the buffer material T. The pressed member P2 is slowly moved downward. Then, the antenna module precursor 13 is pressed toward the stacking direction with a predetermined load (about 10 kg / square cm in this embodiment) through the buffer material T. That is, the antenna module precursor 13 is clamped with a predetermined pressure between the base P1 and the pressing member P2 in a state where the buffer material T is in contact with the upper and lower surfaces of the antenna module precursor 13. As a result, the antenna module 10 shown in FIG. 13B is obtained.

  In addition, by pressing the antenna module precursor 13 with the base P1 and the pressing member P2 through the buffer material T, the impact on the antenna module precursor 13 from the base P1 and the pressing member P2 is reduced, and the antenna module 10 damage is suppressed. Further, since the buffer material T deforms by contacting a hard portion on the upper surface of the antenna module precursor 13, the antenna module precursor 13 is in a state where the buffer material T is in close contact with the upper surface of the antenna base material 140 (release sheet 143). Is pressed with a predetermined load. Therefore, the antenna substrate 140 can be bent and deformed and bonded to the magnetic sheet 110 via the double-sided adhesive layer 120 so as to reduce the cavity S between the magnetic sheet 110 and the antenna substrate 140.

  The manufacturing conditions can be arbitrarily set by those skilled in the art. For example, the buffer material may be a soft synthetic resin, urethane rubber, butyl rubber, or the like. Moreover, as a pressing means, means or an apparatus well-known to those skilled in the art, such as a rubber roller in which a buffering agent is formed on a cylindrical metal surface, and a thermocompression roller (so-called laminator) with a built-in heater, can be arbitrarily selected. Moreover, the thickness of the buffer material is not limited to this embodiment, and can be arbitrarily selected according to the load of the press. Further, the press load can be arbitrarily selected as long as the antenna module precursor is not damaged.

(Experiment)
Next, experimental results of the electromagnetic performance of the antenna module according to one embodiment of the present invention will be shown. The sample of an Example was manufactured as follows and compared with the sample of the comparative example.

(1) Examples First, a sintered ferrite sheet 111 ″ having a thickness of 100 μm in which a groove having a V-shaped cross section of a single-sided lattice was engraved at a depth of 40 μm was prepared. An adhesive layer 112 having a thickness of 10 μm was formed on one surface (the lower surface of the sintered ferrite sheet shown in FIG. 11). A ferrite protective film 113 made of polyethylene terephthalate having a thickness of 10 μm was laminated through the adhesive layer 112 and pressure sensitively bonded.

  As a peeling protective film 125, a pressure-sensitive double-sided adhesive having a thickness of 10 μm with a polyacrylic acid ester having a polyethylene terephthalate film adhering to the front and back as a main component and a softening agent, a pressure-sensitive adhesive, a viscosity agent, etc. as auxiliary components Layer 120 was prepared.

  A pressure-sensitive double-sided adhesive layer 120 having a thickness of 10 μm is formed on the other surface of the sintered ferrite sheet 111 ″ (upper surface in FIG. 11), and a peeling protective film 125 is laminated via the double-sided adhesive layer 120. Next, the laminate is brought into contact with a cylindrical roller having a different direction twice, and a magnetic sheet laminate having a sintered magnetic layer 111 in which a plurality of small pieces 111a of sintered ferrite bodies are assembled. 11 was obtained.

  As the antenna substrate 140, a substrate layer 141 made of polyimide having a thickness of 12.5 μm, a width D of 25 mm, and a length L of 35 mm was prepared. A copper foil antenna pattern having a cross section of a square having a thickness of 35 μm and a width of 400 μm is spirally swirled into a square shape having 5 turns with respect to the lower surface of the antenna base 140 (base layer 141). An antenna coil 130 having a coil pattern was formed by photolithography. Next, a release sheet (or film) 143 was attached to the upper side of the antenna substrate 140 via the adhesive layer 142 to obtain the antenna assembly 12. In the obtained antenna assembly 12, the equivalent width d1 of the coil pattern and the shortest width d2 of the non-antenna pattern region A are 4.8 mm and 10.4 mm, respectively. Therefore, the antenna pattern area ratio α and the short width ratio (d1 / d2) β of this embodiment are 0.46.

  Subsequently, the protective film 125 for peeling the double-sided adhesive layer 120 pressure-sensitively bonded to the magnetic sheet laminate 11 was peeled to expose the upper surface of the double-sided adhesive layer 120. And the pattern surface of the antenna assembly 12 was joined with the exposed surface, and the antenna module precursor 13 was obtained.

  Finally, the antenna module precursor 13 is covered with a 1 mm-thick silicone rubber sheet as a buffer material T and placed on the base P1, and a pressure of 10 kg / square cm is applied from above to the antenna module precursor. 13 was pressed in the stacking direction to obtain the antenna module 10 of this example. In the antenna module 10, the average value of the distance t2 between the antenna coil 130 and the magnetic sheet 110 is about 5 μm. That is, the double-sided adhesive layer 120 is compressed to about ½ of the initial thickness in the region immediately below the conductor portion 131.

  The antenna module 10 is disposed above an aluminum (metal material) plate having a thickness of 5 mm, and the distance between the surface of the antenna coil 130 of the antenna module 10 and the metal material is changed in the range of 25 to 10,000 μm, and the antenna Q value is changed. And the inductance (L value) were measured using an impedance analyzer. The results of this change in electromagnetic characteristics are shown in curve 21 in FIG. 15 and curve 23 in FIG. 16, respectively.

(2) Comparative Example On the other hand, in order to grasp the relative effect of the antenna module according to the present invention, a conventional antenna module 10R was manufactured and compared by the same manufacturing method as the example. As a difference, in the antenna module 10R, an insulating resin protective film 135R having a thickness of 30 μm is formed on the antenna coil 130R of the same antenna assembly 12R used in the above embodiment. And the antenna module 10R shown by the SEM image of FIG. 14 was produced as a comparative example. This antenna module 10R has a total thickness of 52.5 μm including at least a double-sided adhesive layer 120R having a thickness of 10 μm, an insulating resin protective film 135R having a thickness of 30 μm, and a base material layer 141R having a thickness of 12.5 μm. The antenna coil 130 is disposed so as to face the magnetic sheet 110. That is, in the antenna module 10R, from the lower layer, the ferrite protective film 113R, the adhesive layer 112R, the sintered magnetic layer 111R, the double-sided adhesive layer 120R, the insulating resin protective coating 135R, the base material layer 141R, the adhesive layer 142R, The antenna coil 130R, the adhesive layer 144R, and the release sheet 143R are stacked.

  A change in electromagnetic characteristics in the antenna module 10R of the comparative example was measured by the same method as in the example. The results are shown in curve 22 in FIG. 15 and curve 24 in FIG. In addition, the present Example and the comparative example used the protective film which consists of a polyethylene terephthalate, without using electroconductive metal foil (shield layer).

  As is apparent from the curves 21 and 22 showing the electromagnetic characteristics of the antenna module 10 of this embodiment and the antenna module 10R of the comparative example which is a known technique, the Q value of the antenna module 10 of this embodiment is the same antenna pattern. It is relatively 20 or more higher than the Q value of the antenna module 10R of the known technology (comparative example). On the other hand, as is apparent from the curves 23 and 24, the L value (inductance) of the antenna module 10 of the present embodiment is relatively higher by 30 nH or more than the L value of the antenna module 10R of the known technique (comparative example). That is, the experimental results show that the antenna module according to the present embodiment improves the performance of the antenna module as compared with the antenna module having the conventional structure under the condition that the same antenna coil is used. Therefore, the portable information terminal in which the antenna module of the present invention is incorporated can be made smaller.

(Function and effect)
That is, in the antenna module 10 of the present embodiment, as shown in FIG. 8, the double-sided adhesive material layer 120 is relatively pressed toward the magnetic sheet 110 by the antenna coil 130, so that both approach as much as possible. . In particular the total area with the tip of the antenna coil 1 3 0, since smaller than the area of the entire antenna base 140, the load during pressing, bites deep into the double-sided adhesive material layer 120 to concentrate on the tip. As a result, the antenna coil 130 according to the present embodiment has approached the magnetic sheet 110 without limitation to a so-called “direct attachment” structure. Therefore, the antenna module 10 according to the present invention has a space thickness between the portion of the antenna substrate 140 where the antenna coil 130 is not present and the magnetic sheet 110 (that is, the thickness of the bulging double-sided adhesive layer 120). The antenna coil 130 and the magnetic sheet 110 are as close to each other as possible so that the thickness of the space between the antenna coil 130 and the magnetic sheet 110 (that is, the thickness of the crushed double-sided adhesive layer 120) is significantly reduced. It has a so-called “possible direct mounting structure”. That is, in this embodiment, despite the L value and the Q value to determine the quality of the antenna characteristics is relatively small equivalent diameter of the antenna coil, the frequency 13.56MHz band, relatively large L values and Q values Is provided.

At the same time, in the antenna module 10 of the present embodiment, a part of the double-sided adhesive layer 120 is pushed out of the antenna coil 130 and exists in a region where the antenna coil 130 between the magnetic sheet 110 and the antenna substrate 140 does not exist. The double-sided adhesive layer 120 to be expanded is expanded upward. As a result, the bonding area between the antenna coil 130 and the double-sided adhesive layer 120 is increased, and the bonding force between the two is improved. In particular, in the antenna module 10 according to the present embodiment, the ratio β of the non-antenna pattern region A to the short width d2 with respect to the above-described equivalent width d1 is small. In other words, since the antenna pattern region B is relatively wider than the non-antenna pattern region A, the bonding force of the antenna assembly 12 to the double-sided adhesive layer 120 can be sufficiently borne by the antenna pattern region B.

(Second Embodiment)
In the antenna module precursor 13 of the first embodiment described above, the cavity S is formed in the region where the conductor 131 of the antenna coil 130 does not exist over a wide area, that is, in the non-antenna pattern region A and the margin region C. (See FIG. 7). Therefore, when the antenna module precursor 13 is pressed, it is inevitable that the antenna base material 140 and the magnetic sheet 110 are depressed so as to be close to each other in the hollow region. That is, the upper surface (the upper surface of the antenna base 140) or the lower surface (the lower surface of the magnetic sheet 110) of the antenna module 10 includes a curved portion. In the present embodiment, since the magnetic sheet 110 is harder than the antenna base 140, the antenna base 140 is bent downward and deformed as shown in FIG.

Therefore, in the second embodiment, as shown in FIG. 17, in order to minimize the bending of the antenna module 10 ′, a spacer material 150 formed according to the coil pattern of the antenna coil 130 is prepared. The spacer material 150 was stacked on the double-sided adhesive layer 120. The spacer material 150 includes a first spacer material 151 corresponding to the shape of the non-antenna pattern region A and a second spacer material 152 corresponding to the shape of the margin region C. The members of the antenna module 10 ′ of the second embodiment are the same as the members of the antenna module 10 of the first embodiment, except for the spacer material 150, and the description thereof is omitted.

  In the present embodiment, the spacer material 150 has adhesiveness on both surfaces thereof and is made of the same material as the double-sided adhesive layer 120. That is, the spacer material 150 can also be called a double-sided adhesive spacer. However, the material of the spacer material 150 is not limited to this, and the spacer material 150 may be configured not to have an adhesive property as long as the spacer function is filled.

  In the present embodiment, the spacer material 150 has a thickness of about 25 μm. Preferably, the spacer material 150 is designed to approach a thickness obtained by subtracting the thickness (10 μm) of the double-sided adhesive layer 120 from the thickness (35 μm) of the antenna coil 130. That is, the spacer material 150 is designed to have a thickness substantially equivalent to the sum of the thickness of the antenna coil 130 and the thickness of the double-sided adhesive layer 120.

  As shown in FIG. 18, when the first spacer material 151 is disposed in the non-antenna pattern region A and the second spacer material 152 is disposed in the margin region C, the antenna substrate 140 and the double-sided adhesive material layer 120 are interposed. The cavity to be formed is eliminated, and the occurrence of bending of the antenna module surface can be suppressed. That is, the spacer material 150 is bonded to the double-sided adhesive material layer 120 in the non-antenna pattern region A and the margin region C, and the cavity material is filled with the spacer material 150. The antenna substrate 140 is supported from below and maintained on a plane. The upper surface of the antenna base 140 is formed so that the upper surface of the spacer material 150 and the upper surface of the antenna coil 130 are substantially flat. As a result, even when the antenna module precursor 13 is pressed with a predetermined load, the antenna substrate 140 is maintained in a flat state.

  Therefore, the antenna module 10 ′ can be incorporated into the portable information terminal in a state where the antenna substrate 140 is not bent. Further, the magnetic sheet 110 and the antenna substrate 120 can be more strongly bonded by arranging the spacer material 150 between the double-sided adhesive layer 120 and the antenna antenna substrate 140.

  Here, the spacer material 150 may be formed integrally with the double-sided adhesive layer 120. In that case, the double-sided adhesive layer 120 and the spacer material 150 are integrated so that the portions corresponding to the non-antenna pattern region A and the margin region C are thicker than the portion corresponding to the antenna pattern region B of the double-sided adhesive layer 120. Combined. Further, the spacer member 150 may be coupled to the lower surface of the antenna base 140 so as to be fitted into the non-antenna pattern region B and the margin region C of the antenna module 12. Furthermore, in this embodiment, the spacer material 150 is disposed in both the non-antenna pattern region A and the margin region C, but the spacer material 150 can be disposed only in one of them. Furthermore, the antenna substrate may be maintained in a flat state by juxtaposing the specific spacer with another double-sided adhesive having a specific thickness and planar shape without overlapping the double-sided adhesive layer and the spacer material. .

  FIG. 19 is an exploded perspective view of an antenna module 10 ″ which is a modification of the second embodiment. A spacer member 153 of the antenna module 10 ″ is formed by integrally forming first and second spacer members 151 and 152. In addition, it has a shape that can be inserted into the gap 132 of the antenna coil 130. That is, the spacer material 153 has a planar shape that is in a complementary relationship with respect to the projection plane of the conductor 131 of the antenna coil 130. As shown in FIG. 20, the spacer material 153 is disposed in a space where the antenna conductor (the conductive wire portion 131 and the connection pad 132) does not exist, that is, the gap portion 132, the non-antenna pattern region A, and the margin region C. In this modification, the spacer material 153 is bonded to the double-sided adhesive layer 120 in the non-antenna pattern region A and the margin region C, and the bulging portion 122 that protrudes upward in the gap portion 132 is bonded to the spacer material 153. ing. Therefore, according to the antenna module 10 ″, by introducing the spacer material 153, it is possible to effectively suppress the bending of the antenna base 140 on the gap 132.

  The present invention can be carried out by changing or developing a part of the embodiment as long as the fundamental technical idea is followed and the effect of the invention is not significantly impaired. For example, the flexible conductive metal foil affixed to the surface of the magnetic sheet in the embodiments can be used and developed as a shield material for the antenna module according to the present invention.

  That is, when an antenna module is incorporated in a portable information terminal, it is flexible with respect to the portable information terminal via an insulating layer having a predetermined thickness, for example, an organic adhesive layer, on the side of the enclosed metal, for example, the battery pack. When the conductive conductive metal foil is incorporated, the flexible conductive metal foil keeps the influence of various eddy currents generated at the time of driving the antenna in a predetermined fixed range according to the type, shape and size of the metal of the portable information terminal. It can be used for applications that demonstrate the shielding effect.

  The present invention can be widely used in the field of high-performance portable terminals and other non-contact wireless antennas in which an electronic solid recognition system is incorporated.

DESCRIPTION OF SYMBOLS 10 Antenna module 11 Magnetic sheet laminated body 12 Antenna assembly 13 Antenna module precursor 110 Magnetic sheet 111 Sintered magnetic body layer 111a Small piece 111b Dividing groove 111 'Green ferrite sheet 111 "Sintered ferrite sheet 112 Adhesive material layer 113 Ferrite protective film 114 Flexible conductive metal foil 120 Double-sided adhesive layer 121 Crushing portion 122 Swelling portion 125 Peeling protective film 130 Antenna coil 131 Conducting wire portion 132 Gap portion 133 Connection pad 140 Antenna base material 141 Base material layer 142 Adhesive material layer 143 Release sheet 150 Spacer material A Non-antenna pattern area B Antenna pattern area C Margin area D Short width b1 to b4 Partition pattern area c1 Innermost loop c2 Outermost loop d1 Equivalent width d2 of coil pattern Non-antenna pattern Short width of over emission area
d3 Thickness d4 Conductor width P1 Base P2 Pressing part T Buffer material

Claims (23)

A magnetic sheet for focusing the magnetic flux;
A double-sided adhesive layer bonded to the top surface of the magnetic sheet;
An antenna coil having a conductor portion and a gap portion of a predetermined coil pattern laminated on the double-sided adhesive layer;
An antenna substrate laminated on the antenna coil,
The double-sided adhesive layer is crushed and deformed between the antenna coil and the magnetic sheet so that the antenna coil and the magnetic sheet are as close as possible to each other, and at least the gap portion of the antenna coil The antenna module is characterized in that a part of the double-sided adhesive layer bulges and a distance between the antenna coil and the magnetic sheet is 0.1 μm to 30 μm . A magnetic sheet for focusing magnetic flux, with a flexible conductive metal foil bonded to the lower surface;
A double-sided adhesive layer bonded to the top surface of the magnetic sheet;
An antenna coil having a conductor portion and a gap portion of a predetermined coil pattern laminated on the double-sided adhesive layer;
An antenna substrate laminated on the antenna coil,
The double-sided adhesive layer is crushed and deformed between the antenna coil and the magnetic sheet so that the antenna coil and the magnetic sheet are as close as possible to each other, and at least the gap portion of the antenna coil The antenna module is characterized in that a part of the double-sided adhesive layer bulges and a distance between the antenna coil and the magnetic sheet is 0.1 μm to 30 μm . A magnetic sheet for focusing the magnetic flux;
A double-sided adhesive layer bonded to the top surface of the magnetic sheet;
An antenna coil having a conductor portion and a gap portion of a predetermined coil pattern laminated on the double-sided adhesive layer;
An antenna substrate laminated on the antenna coil;
A spacer material having a predetermined thickness disposed in at least a part of the non-antenna pattern region of the antenna coil,
A part of the double-sided adhesive material layer and the spacer material are bonded in the non-antenna pattern region .   A spacer material having a predetermined thickness is disposed in the non-antenna pattern region (A) inside the innermost loop of the antenna coil, and a part of the double-sided adhesive material layer and the non-antenna pattern region (A) The antenna module according to any one of claims 1 to 3, wherein a spacer material is coupled.   A spacer material having a predetermined thickness is disposed in the outer margin region (C) of the outermost loop of the antenna coil, and a part of the double-sided adhesive material layer and the spacer material are coupled in the margin region (C). The antenna module according to any one of claims 1 to 3, wherein the antenna module is provided.   A first spacer material having a predetermined thickness is disposed in the inner non-antenna pattern region (A) inside the innermost loop of the antenna coil, and a margin region (C outside the outermost loop of the antenna coil). ), A second spacer material having a predetermined thickness is disposed, and a part of the double-sided adhesive material layer and the first and second adhesive layers are formed in both the non-antenna pattern region (A) and the margin region (C). The antenna module according to any one of claims 1 to 3, wherein a spacer material is coupled.   The coil pattern has an outermost loop and an innermost loop, a distance (d1) between the outer edge of the outermost loop and the inner edge of the innermost loop, and a short width (d2) of the innermost loop. The antenna module according to claim 1, wherein the ratio (d1 / d2) is in the range of 0.2 to 1.5. The antenna module according to claim 3 , wherein the spacer material has a thickness corresponding to a sum of a thickness of the antenna coil and the double-sided adhesive material layer.   The magnetic sheet includes a ferrite protective film, an adhesive layer disposed on the ferrite protective film, and a sintered magnetic layer in which a plurality of small pieces adhered to the upper surface of the adhesive layer are gathered. The antenna module according to any one of claims 1 to 8.   The antenna module according to claim 9, wherein the ferrite protective film is a protective film for peeling.   The magnetic sheet is a sintered magnetic body in which a flexible conductive metal foil, an adhesive layer disposed on the flexible conductive metal foil, and a plurality of small pieces bonded to the upper surface of the adhesive layer are gathered. The antenna module according to claim 1, further comprising: a layer.   The antenna substrate includes a substrate layer on which the antenna coil is formed on the lower surface and an adhesive layer formed on the upper surface of the substrate layer, and a release sheet is attached to the upper surface of the adhesive layer. The antenna module according to any one of claims 1 to 11, wherein the antenna module is provided.   The antenna module according to any one of claims 1, 2, 3, and 12, wherein the antenna substrate is substantially held in a planar state.   14. The antenna module according to claim 1, wherein the magnetic sheet is a Ni—Zn—Cu system in which a real part μr ′ of magnetic permeability is 70 or more and an imaginary part μr ″ of magnetic permeability is 15 or less. 15. . Preparing a magnetic sheet for focusing magnetic flux;
Depositing a double-sided adhesive layer on the magnetic sheet;
A step of forming an antenna module precursor by laminating an antenna assembly including an antenna coil having a conductor portion and a gap portion of a predetermined coil pattern, and an antenna base material coupled to the antenna coil on the double-sided adhesive layer. When,
In order to bring the antenna coil and the magnetic sheet as close as possible to each other, a part of the double-sided adhesive layer bulges at least in the gap portion of the antenna coil and directly or indirectly on the lower surface of the antenna substrate. manner to couple, it viewed including the steps of: pressing through a buffer material in the stacking direction the antenna module precursor,
A method for manufacturing an antenna module, wherein a distance between the antenna coil and the magnetic sheet is 0.1 μm to 30 μm . The method further includes disposing a spacer material having a predetermined thickness in a non-antenna pattern region inside the innermost loop of the antenna coil, and when the antenna module precursor is pressed, a part of the double-sided adhesive material layer is not in the non-antenna pattern region. The manufacturing method according to claim 15 , wherein the spacer material is bonded to the spacer pattern region. The method further includes a step of disposing a spacer material having a predetermined thickness in an outer margin region of the outermost loop of the antenna coil, and pressing the antenna module precursor causes a part of the double-sided adhesive layer to be in the margin region . The manufacturing method according to claim 15, wherein the manufacturing method is combined with a spacer material. Disposing first and second spacer members in a non-antenna pattern region inside the innermost loop of the antenna coil and a margin region outside the outermost loop of the antenna coil; When pressing the precursor, the production method according to claim 15, wherein a part of the double-sided adhesive material layer is bonded to the non-antenna pattern region and the first and second spacer material in the marginal region .   The double-sided adhesive layer has a protective film for peeling on at least one side, and before the antenna coil is laminated on the double-sided adhesive layer and / or the double-sided adhesive layer on the magnetic sheet. The method for manufacturing an antenna module according to any one of claims 15 to 18, further comprising a step of peeling the protective film for peeling before deposition.   The magnetic sheet includes a ferrite protective film, an adhesive layer disposed on the ferrite protective film, and a sintered magnetic layer in which a plurality of small pieces adhered to the upper surface of the adhesive layer are gathered. The method for manufacturing an antenna module according to any one of claims 15 to 19.   The magnetic sheet is a sintered magnetic body in which a flexible conductive metal foil, an adhesive layer disposed on the flexible conductive metal foil, and a plurality of small pieces bonded to the upper surface of the adhesive layer are gathered. The method for manufacturing an antenna module according to claim 15, further comprising: a layer.   The coil pattern has an outermost loop and an innermost loop, a distance (d1) between the outer edge of the outermost loop and the inner edge of the innermost loop, and a short width (d2) of the innermost loop. The method of manufacturing an antenna module according to any one of claims 15 to 21, wherein the ratio (d1 / d2) is in a range of 0.2 to 1.5. A magnetic sheet for focusing the magnetic flux;
A double-sided adhesive layer bonded to the top surface of the magnetic sheet;
An antenna coil having a conductor portion and a gap portion of a predetermined coil pattern laminated on the double-sided adhesive layer;
An antenna base material comprising an antenna substrate laminated on the antenna coil,
The double-sided adhesive layer is pressed between the antenna coil and the magnetic sheet by being pressed with a predetermined load in the stacking direction via a cushioning material so that the antenna coil and the magnetic sheet are as close as possible to each other. By being crushed and deformed, at least a part of the double-sided adhesive layer swells in the gap portion of the antenna coil, and the distance between the antenna coil and the magnetic sheet is 0.1 μm to 30 μm , antenna module precursor, characterized in that from the antenna module precursor allows making the antenna module.