JP2005015293A - Sintered ferrite substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sintered ferrite substrate with high magnetic permeability capable of repeating sticking and peeling along a plane, curved surface or projecting and recessing surface and which is free from powdering. <P>SOLUTION: In the sintered ferrite substrate provided with an adhesive material layer on one side of a sintered ferrite plate, the sintered ferrite plate is constituted so as to be separated using at least one continuous groove as a start point provided on at least one side surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sintered ferrite substrate, and more particularly to a sintered ferrite substrate that can be attached to and peeled from a flat, curved, or uneven surface of an electronic device.
[0002]
[Prior art]
Conventionally, an electronic device or the like is a composite composed of a magnetic material such as an amorphous magnetic material or ferrite and a binder resin in order to absorb electromagnetic waves radiated from the electronic device or the like and to absorb electromagnetic waves that enter the electronic device. A magnetic body such as a magnetic body or sintered ferrite is mounted. In particular, in an RFID (Radio Frequency IDentification) tag that communicates with an electromagnetic wave using an antenna coil, when a conductive member such as metal is present in the vicinity of the antenna coil, for example, on the rear side, the reflected electromagnetic wave is Interference may make transmission and reception difficult. Therefore, attention has been paid to a method of suppressing reflection of electromagnetic waves by disposing a magnetic material having high permeability between the antenna coil of the RFID tag and the conductive member.
[0003]
As a magnetic material having a high magnetic permeability to be mounted on an electronic device, a magnetic protective sheet in which an amorphous magnetic material formed in a flake shape is uniformly dispersed in an insulating film is described (see Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-79127
Although the above-mentioned amorphous magnetic body has a high magnetic permeability, it is very expensive as compared with a plate-like ferrite sintered body, so that an inexpensive RFID tag cannot be provided. On the other hand, a plate-like magnetic sintered body made of sintered ferrite has a high magnetic permeability, but is vulnerable to mechanical stress and impact. In particular, when it is thinned, there is a problem that it is damaged by slight impact. Furthermore, since the plate-like ferrite sintered body is hard and brittle, it is difficult to adhere or substantially adhere the plate-like magnetic sintered body along the curved surface or the uneven surface of the object to be adhered. Is difficult to repeat.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and its purpose is to repeat the pasting and peeling along a plane, curved surface or uneven surface, and to sinter with high magnetic permeability without powder falling. It is to provide a ferrite substrate.
[0007]
[Means for Solving the Problems]
The inventors of the present invention provide a sintered ferrite substrate provided with at least one continuous groove on at least one surface of a sintered ferrite plate having an adhesive layer on one surface along a curved surface or an uneven surface of an electronic device. Surprisingly, when the sintered ferrite plate breaks at the groove, it can be repeatedly stuck and peeled without losing any powder and without being damaged in an irregular shape. In addition, it has been found that even when the sintered ferrite plate is broken at the groove, the permeability of the sintered ferrite substrate is little lowered.
[0008]
The present invention has been completed based on the above findings, the gist of which is a sintered ferrite substrate having an adhesive material layer provided on one surface of a sintered ferrite plate, The sintered ferrite substrate is characterized in that it can be divided starting from at least one continuous groove provided on at least one surface.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view of a sintered ferrite substrate composed of a sintered ferrite plate and an adhesive layer, and FIGS. 2 to 4 are longitudinal sectional views of the sintered ferrite substrate showing a state in which grooves are formed. . 2 to 3, the sintered ferrite substrate (1) has an adhesive layer (5) on one side of the sintered ferrite plate (2) and a sintered ferrite plate (2) opposite to the adhesive layer (5). ) And a groove (3, 4) on the surface of the sintered ferrite plate opposite to the adhesive layer (5). In FIG. (1) has an adhesive layer (5) on one side of the sintered ferrite plate (2) and a groove (4) on the opposite side of the surface of the sintered ferrite plate from the adhesive layer (5) side. ing.
[0010]
The sintered ferrite is not particularly limited as long as it is soft ferrite, and known soft ferrite can be used. For example, Mn—Zn ferrite, Ni—Zn ferrite, Ni—Zn—Cu ferrite, Mn—Mg ferrite, Li ferrite and the like can be mentioned. Also, soft ferrite whose composition is changed according to the frequency of the electromagnetic wave to be used can be used.
[0011]
The thickness of the sintered ferrite plate (2) is usually 0.1 mm to 5 mm, preferably 0.1 to 3 mm, more preferably 0.1 to 1 mm. If the thickness is less than 0.1 mm, it is difficult to provide a groove, and repeated sticking and peeling on the curved surface or uneven surface of the object to be adhered will cause cracking in other than the groove, resulting in powder falling and transparent Decrease in magnetic susceptibility is unfavorable. If it exceeds 5 mm, the weight of the sintered ferrite substrate increases, which is not preferable.
[0012]
An example of the adhesive layer (5) is a double-sided adhesive tape. It does not restrict | limit especially as a double-sided adhesive tape, A well-known double-sided adhesive tape can be used. Further, as the adhesive layer (5), an adhesive layer, a flexible and stretchable film or sheet, an adhesive layer and a release sheet may be sequentially laminated on one side of the sintered ferrite plate (2). Good.
[0013]
The shape of the cross section perpendicular to the longitudinal direction of the groove formed on the surface opposite to the surface on which the adhesive layer (5) of the sintered ferrite plate (2) is formed is that the sintered ferrite plate (2) is a groove portion. There is no particular limitation as long as it can be divided. For example, as long as the sintered ferrite plate can be divided at the groove, the sintered ferrite plate can be provided with flexibility, and the permeability of the sintered ferrite plate is small when it is cracked. A U-shaped groove (3) having a U-shaped cross section perpendicular to the longitudinal direction of the groove or a V-shaped groove (4) having a V shape may be mentioned.
[0014]
The width of the opening of the groove (3, 4) is usually 250 μm or less, preferably 1 to 150 μm. When the width of the opening exceeds 250 μm, the decrease in the magnetic permeability of the sintered ferrite substrate becomes large, which is not preferable. The depth of the groove is usually 1/20 to 3/5 of the thickness of the sintered ferrite plate (2). In the case of a thin sintered ferrite plate having a thickness of 0.1 mm to 0.2 mm, the depth of the groove is preferably 1/20 to 1/4 of the thickness of the sintered ferrite plate, more preferably 1 / 20 to 1/6.
[0015]
The surface of the sintered ferrite plate (2) is divided into triangles, quadrilaterals, polygons or combinations thereof of any size by the grooves (3, 4). For example, the length of one side of a triangle, a quadrangle, or a polygon is usually 1 to 12 mm, and when the adhesion surface of the adherend is a curved surface, it is preferably 1 mm or more and 1/3 or less of the radius of curvature thereof, More preferably, it is 1 mm or more and 1/4 or less. When the length of one side of a triangle, a quadrilateral, or a polygon is 1 to 12 mm, the sintered ferrite substrate of the present invention does not crack indefinitely in a place other than a groove, and of course, a cylindrical side curved surface In addition, it can be adhered or substantially adhered to a surface with some unevenness.
[0016]
By forming a protective layer (6) on the surface of the sintered ferrite plate opposite to the adhesive layer, the reliability and durability are further improved against powder falling when the sintered ferrite plate is divided at the groove. I can do it. The protective layer (6) is not particularly limited as long as the sintered ferrite plate is a resin that extends without breaking when the sintered ferrite plate is folded in the groove, and the tensile fracture elongation at room temperature is usually 350% or more. A thermoplastic resin or rubber having excellent adhesion can be used. For example, examples of the resin constituting the protective layer include polyurethane resins, styrene-butadiene elastomers, and butadiene-based elastomers. The thickness of the protective layer (6) is usually 0.005 to 0.2 mm, preferably 0.01 to 0.1 mm. When the thickness of the protective layer is less than 0.005 mm, it is easy to break and it is difficult to prevent powder falling. When the thickness exceeds 0.2 mm, the effect of preventing powder falling is saturated, so that it is not necessary to increase the thickness beyond 0.2 mm.
[0017]
Next, the manufacturing method of the sintered ferrite substrate of the present invention will be described. The sintered ferrite plate can be manufactured by a known method. For example, after ferrite powder and binder resin are mixed, a ferrite plate is formed by a powder compression molding method, injection molding method, calendar method, extrusion method, etc., degreased as necessary, and then sintered and manufactured. I can do it. Also, after mixing ferrite powder, binder resin and solvent, a green sheet is obtained by coating with a doctor blade or the like on a film or sheet, and after degreasing as necessary, the obtained green sheet is sintered. Can be processed and manufactured. A plurality of obtained green sheets may be laminated.
[0018]
The groove can be formed during the molding of the ferrite plate, after the molding or after the sintering process. For example, when molding by powder compression molding method or injection molding method, it is preferable to form during molding, and when molding by calendar method or extrusion method, it is preferable to form after molding and before sintering, When manufacturing a sintered ferrite board via a sheet | seat, forming in a green sheet is preferable.
[0019]
A known method can be used as the powder compression molding method. For example, a ferrite powder and a thermosetting resin such as an epoxy resin as a binder resin are mixed and compression-molded, and heated as necessary to obtain a harder molded body, and then sintered. Further, a thermoplastic resin such as polyvinyl alcohol resin or ethylene vinyl acetate resin is used as the binder resin, and the mixture with the ferrite powder is compression-molded, the binder resin is removed (degreasing treatment), and then the sintering treatment is performed.
[0020]
As the injection molding method, a known method can be used. For example, after ferrite powder and a resin used in the metal injection mold method as a binder resin, for example, polybutyl methacrylate resin, ethylene vinyl acetate resin, etc. are mixed and injection molded, and the binder resin is removed (degreasing treatment) , Sintering process. As the calendar method, a known method can be used. For example, ferrite powder and thermoplastic resin such as polybutyl methacrylate resin and ethylene vinyl acetate resin are mixed as binder resin, a sheet is formed with a calender roll, cut into a predetermined dimension, and binder resin is removed (degreasing treatment) ) And then a sintering process. As the extrusion method, a known method can be used. For example, after ferrite powder and thermoplastic resin such as ethylene vinyl acetate resin are mixed as binder resin, a sheet is formed by T-die method, cut to a predetermined size, and binder resin is removed (degreasing treatment) , Sintering process.
[0021]
The green sheet is a film or sheet obtained by mixing a ferrite powder and a binder resin, for example, a thermoplastic resin such as butylphthalylbutyl glycolate and butyral resin, and an organic solvent such as isopropyl alcohol and toluene as a solvent. A sintered ferrite plate obtained by coating on the green sheet, usually having a thickness of 1 to several hundred μm. Moreover, the sintered ferrite plate obtained from the laminated body which laminated | stacked the several green sheet has thickness of several hundred micrometers or more.
[0022]
The degreasing treatment is usually performed at a temperature of 150 to 500 ° C. for 20 to 180 minutes. The sintering temperature is usually 850 to 1050 ° C, preferably 875 to 1025 ° C. The sintering time is usually 30 to 180 minutes, preferably 45 to 120 minutes. When the sintering temperature is less than 850 ° C., it becomes difficult to sinter the particles, and the strength of the obtained sintered ferrite plate cannot be said to be sufficient. On the other hand, if the sintering temperature exceeds 1050 ° C., the growth of particles proceeds, which is not preferable. When the sintering time is less than 30 minutes, it becomes difficult to sinter the particles, and the obtained sintered ferrite plate cannot be said to have sufficient strength. Further, since the sintering of the particles proceeds sufficiently when the sintering time is 180 minutes, it is not necessary to increase the sintering time beyond 180 minutes.
[0023]
Next, an adhesive material layer, for example, a double-sided adhesive tape, is provided on the surface of the obtained sintered ferrite plate where the grooves are formed or on the opposite surface. And the protective layer for powder fall prevention is provided in the surface on the opposite side to the surface in which the adhesive material layer is formed. The protective layer is formed by adhering a resin film or sheet constituting the protective layer to the surface of the sintered ferrite plate through an adhesive, if necessary, or by applying a paint containing the resin constituting the protective layer. This is done by applying to the surface of the sintered ferrite plate.
[0024]
The sintered ferrite substrate of the present invention is a sintered ferrite substrate starting from at least one continuous groove when pasted along a curved surface portion or an uneven surface portion of an adherend, for example, an electronic device or an electronic component. By bending or bending, it adheres closely to flat surfaces as well as cylindrical side curved surfaces and surfaces with some irregularities, without cracking irregularly in places other than grooves and without causing powder-off phenomenon. Or it can contact | adhere substantially. By using the sintered ferrite substrate of the present invention, the sintered ferrite plate is not damaged indefinitely, and the phenomenon of powder falling does not occur. It becomes easy to repeat sticking and peeling along the surface.
[0025]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. For the magnetic permeability, an impedance analyzer HP4291A (manufactured by Hewlett-Packard Company) and a jig (HP1645A) mounted on the test station are used for a sample having an outer diameter of 14 mm, an inner diameter of 8 mm, and a thickness of 0.4 to 20 mm. Then, the frequency was measured at 13.56 MHz. The magnetic permeability is a value of the real part of the complex magnetic permeability.
[0026]
Example 1
100 parts by weight of Ni-Zn-Cu ferrite FRX-952 (trade name, manufactured by Toda Kogyo Co., Ltd.) as magnetic powder, 2 ml of butylphthalylbutyl glycolate, 12 parts by weight of butyral resin and 100 ml of toluene as a solvent are mixed and dissolved in a ball mill. Distributed. After defoaming under reduced pressure with an oil rotary vacuum pump, the resulting mixture was applied to a 100 μm thick polyethylene terephthalate (PET) film with a doctor blade to a certain thickness and dried with hot air at 100 ° C. for 30 minutes. A green sheet having a thickness of 100 μm was obtained. 5 sheets of the obtained green sheets were stacked, put in a water and heat resistant bag and degassed, and then the opening of the bag was sealed and hydrostatically pressed for 20 minutes while heating to 80 ° C.
[0027]
The surface of a laminated green sheet having a thickness of 500 μm obtained using a blade having a tip having a triangular cross section (V shape) and a thickness of 200 μm from the tip of the blade having a thickness of 200 μm. A groove having a depth of 200 μm was formed in a lattice pattern with a width of 3 mm. Next, the temperature was raised from room temperature to 500 ° C. at a temperature rising rate of 0.5 ° C./min, held at 500 ° C. for 6 hours for degreasing, then heated to 900 ° C. and sintered for 2 hours. The thickness of the obtained sintered plate is about 0.4 mm, and the grooves are grid-like V-shaped grooves with a width of 2.6 mm. The width of the groove opening is about 110 μm and the depth of the groove is about 100 μm. Met.
[0028]
Urethane resin sample IB-422 (trade name, manufactured by Sanyo Kasei Co., Ltd.) was applied to the surface of the obtained sintered plate where the grooves were formed, and dried at 50 ° C. for 3 minutes. The thickness of the obtained protective layer was 0.015 mm. Next, a commercially available double-sided tape was applied to the surface of the sintered plate opposite to the protective layer to obtain a sintered ferrite substrate. The permeability μ of the sintered ferrite substrate was 162.
[0029]
The sintered ferrite substrate obtained was pasted on the back surface of the identification tag in which the IC and the communication loop antenna were integrated. Next, in the data carrier device described in Japanese Patent No. 3262948, when the identification tag member obtained instead of the responder was mounted on the surface of the metal box, the response with the interrogator was good, and the sintered ferrite substrate was The influence of metal could be eliminated. In addition, the sintered ferrite substrate could be easily peeled off from the identification tag without breakage from the groove and the occurrence of damage to the irregular shape and powder falling phenomenon. This sintered ferrite substrate could be used repeatedly. The peeled sintered ferrite substrate was in a state of being broken at the groove portion, and its magnetic permeability μ was 100.
[0030]
Example 2
Ni-Zn-Cu ferrite FRX as a magnetic powder and a resin component comprising 23% by weight of ethylene vinyl acetate resin, 30% by weight of polybutyl methacrylate, 10% by weight of dioctyl phthalate, 17% by weight of dibutyl phthalate and 20% by weight of normal paraffin wax -955 (trade name, manufactured by Toda Kogyo Co., Ltd.) was mixed and dispersed to obtain a composition having a magnetic powder amount of 68% by volume.
[0031]
The obtained composition was injection-molded to form a plate-like body having a length of 59 mm, a width of 47 mm, and a thickness of 0.7 mm. The injection mold is provided with protrusions having a reverse U-shaped cross section orthogonal to the longitudinal direction in advance in a lattice shape, and the molded injection molded body has a U-shaped cross section. The letter-shaped grooves were formed in a lattice shape. Subsequently, the obtained plate-like body was treated at a temperature of 100 ° C. for 2 hours, then treated at a temperature of 120 ° C. for 2 hours, and further treated at a temperature of 2000 ° C. for 2 hours to remove the resin component, and then 5 ° C. / The temperature was raised to 900 ° C. at a rate of minutes, and the temperature was maintained for 2 hours to obtain a sintered plate. The obtained sintered plate has a thickness of 0.6 mm, a length of 50 mm, and a width of 40 mm, and the grooves are grid-shaped U-shaped grooves with a width of 2.5 mm, and the width of the groove opening is about 100 μm. The depth of the groove was about 200 μm.
[0032]
Urethane resin sample IB-422 (trade name, manufactured by Sanyo Kasei Co., Ltd.) was applied to the surface of the obtained sintered plate where the grooves were formed, and dried at 50 ° C. for 3 minutes. The thickness of the obtained protective layer was 0.015 mm. Next, a double-sided tape (Nystack, manufactured by Nichiban Co., Ltd.) was applied to the surface of the sintered plate opposite to the protective layer to obtain a sintered ferrite substrate. The obtained sintered substrate had a magnetic permeability μ of 98, and the magnetic permeability μ was 71 in a state where the sintered substrate was bent starting from the groove. As a result of mounting on the back side of the identification tag as in Example 1, the response with the interrogator was good. In addition, the sintered ferrite substrate could be easily peeled off from the identification tag without being broken from the groove, causing damage to an indeterminate shape and powder falling off, and could be used repeatedly.
[0033]
Example 3
A composition was obtained in the same manner as in Example 2 except that Ni-Zn-Cu ferrite FRX-146 (trade name, manufactured by Toda Kogyo Co., Ltd.) was used as the magnetic powder. The obtained composition was calender-rolled to obtain a sheet having a thickness of 0.88 mm, and then punched into a size of 59 mm in length and 47 mm in width to obtain a molded sheet. At the same time as punching, V-shaped grooves were formed in a lattice shape.
[0034]
Next, the temperature was raised from room temperature to 500 ° C. at a heating rate of 0.5 ° C./min, degreased by holding at 500 ° C. for 2 hours, and then heated to 900 ° C. for sintering. The obtained sintered plate has a thickness of 0.75 mm, a length of 50 mm, and a width of 40 mm. The grooves are grid-shaped V-shaped grooves with a width of 2.6 mm, and the width of the groove opening is about 190 μm. The groove depth was about 170 μm.
[0035]
Urethane resin sample IB-422 (trade name, manufactured by Sanyo Kasei Co., Ltd.) was applied to the surface of the obtained sintered plate where the grooves were formed, and dried at 50 ° C. for 3 minutes. The thickness of the obtained protective layer was 0.02 mm. Next, a commercially available double-sided tape was applied to the surface of the sintered plate opposite to the protective layer to obtain a sintered ferrite substrate. The magnetic permeability μ of the obtained sintered ferrite substrate was 178, and the magnetic permeability μ was 112 in a state where the sintered ferrite substrate was bent starting from the groove. As a result of mounting on the back surface of the identification tag in the same manner as in Example 1, the response to the question pad was good. In addition, the sintered ferrite substrate could be easily peeled off from the identification tag without being broken from the groove, causing damage to an indeterminate shape and powder falling off, and could be used repeatedly.
[0036]
Example 4
80 ml of an aqueous solution containing 2.5% by weight of polyvinyl alcohol (PVA) resin is added to 1 kg of Ni-Zn-Cu ferrite FRX-952 (trade name, manufactured by Toda Kogyo Co., Ltd.), mixed and dried, so that the PVA resin is on the surface. An attached magnetic powder was obtained. Next, the obtained composition was compression-molded to produce a block-shaped molded article, and then heated to 900 ° C. and sintered at that temperature for 2 hours. From the obtained sintered block, a sintered substrate having a thickness of 0.8 mm, a length of 50 mm, and a width of 40 mm was cut out, and V-shaped grooves were cut into a lattice shape on one side in a lattice shape with a width of 4 mm. The width of the opening of the groove was 200 μm, and the depth of the groove was 200 μm.
[0037]
Urethane resin sample IB-422 (trade name, manufactured by Sanyo Kasei Co., Ltd.) was applied to the surface of the obtained sintered plate where the grooves were formed, and dried at 50 ° C. for 3 minutes. The thickness of the obtained protective layer was 0.02 mm. Subsequently, a commercially available double-sided tape was stuck on the surface of the sintered plate opposite to the protective layer to obtain a sintered ferrite substrate. The obtained sintered ferrite substrate had a magnetic permeability μ of 169 and a magnetic permeability μ of 110 in a state where the sintered ferrite substrate was bent starting from the groove. As a result of mounting on the back surface of the identification tag in the same manner as in Example 1, the response to the question pad was good. In addition, the sintered ferrite substrate could be easily peeled off from the identification tag without being broken from the groove, causing damage to an indeterminate shape and powder falling off, and could be used repeatedly.
[0038]
Example 5
80 ml of an aqueous solution containing 2.5% by weight of polyvinyl alcohol (PVA) resin is added to 1 kg of Ni-Zn-Cu ferrite FRX-952 (trade name, manufactured by Toda Kogyo Co., Ltd.), mixed and dried, so that the PVA resin is on the surface. An attached magnetic powder was obtained. Subsequently, the obtained composition was compression molded to produce a plate-shaped molded product. In addition, the compression mold part which forms the opposing surface of a plate-shaped molding is provided with protrusions having a reverse U-shaped and inverted V-shaped cross section orthogonal to the surface in a lattice shape in advance. In the obtained plate-like molded body, a U-shaped groove having a U-shaped cross section and a V-shaped groove having a V-shaped cross section were formed in a lattice shape.
[0039]
Next, the obtained plate-like molded body was heated to 900 ° C. at a rate of 5 ° C./min and held at that temperature for 2 hours to obtain a sintered plate. The obtained sintered plate had a thickness of 2 mm, a length of 50 mm, and a width of 40 mm. Lattice-like grooves are formed at substantially the same position on both surfaces of the sintered plate, and the grooves on one surface are lattice-shaped V-shaped grooves with a width of 8 mm, and the width of the groove opening is about 0.3 mm. The groove depth is about 0.3 mm, and the groove on the other surface is a grid-like U-shaped groove with a width of 8 mm, the groove opening width is about 0.2 mm, and the groove depth is About 0.4 mm.
[0040]
Next, a commercially available double-sided tape was affixed to the surface of the sintered plate on which the U-shaped groove was formed to obtain a sintered ferrite substrate. The sintered substrate thus obtained had a magnetic permeability μ of 175, and the magnetic permeability μ was 135 in a state where the sintered substrate was bent starting from the groove. As a result of mounting on the back side of the identification tag as in Example 1, the response with the interrogator was good. In addition, the sintered ferrite substrate could be easily peeled off from the identification tag without being broken into an indeterminate shape with the groove as a starting point, and could be used repeatedly. Moreover, there was almost no powder fall-off.
[0041]
Comparative Example 1
A sintered ferrite substrate was obtained in the same manner as in Example 1 except that no groove was formed on the surface of the green sheet. Furthermore, even after trying to peel the sintered ferrite substrate from the identification tag after attaching the sintered ferrite substrate to the identification tag in the same manner as in Example 1, it could not be easily peeled off. When it was forcibly peeled off, a part of the sintered ferrite substrate was damaged in an irregular shape, small pieces were scattered, and a powder falling phenomenon occurred.
[0042]
【The invention's effect】
According to the present invention described above, the sintered ferrite substrate of the present invention is configured so that the sintered ferrite plate can be divided starting from the groove, and preferably opposite to the surface on which the adhesive layer is formed. Since a protective layer is provided on the side surface to prevent powder falling, the sintered ferrite plate is stuck along the curved or uneven surface of an electronic device without causing damage to the irregular shape and powder falling phenomenon. It is easy to repeat or peel off. And since the sintered ferrite board has little fall of magnetic permeability even if a sintered ferrite board bends in the part of a slot, the industrial value of the present invention is remarkable.
[Brief description of the drawings]
FIG. 1 is a plan view of a sintered ferrite substrate. FIG. 2 is a longitudinal sectional view of a sintered ferrite substrate having a U-shaped groove. FIG. 3 is a longitudinal sectional view of a sintered ferrite substrate having a V-shaped groove. ] Vertical cross section of sintered ferrite substrate with grooves on both surfaces [Explanation of symbols]
1: sintered ferrite substrate 2: sintered ferrite plate 3: U-shaped groove 4: V-shaped groove 5: adhesive layer 6: protective layer

Claims (6)

A sintered ferrite substrate having an adhesive material layer provided on one surface of a sintered ferrite plate, the sintered ferrite plate being separable starting from at least one continuous groove provided on at least one surface A sintered ferrite substrate characterized by comprising. The sintered ferrite substrate according to claim 1, wherein a protective layer is provided on the surface of the sintered ferrite plate opposite to the adhesive material layer. The sintered ferrite substrate according to claim 1 or 2, wherein the groove is a groove continuous in one direction and a groove intersecting with the groove. The sintered ferrite substrate according to claim 1, wherein the groove is a U-shaped groove or a V-shaped groove. The sintered ferrite substrate according to any one of claims 1 to 4, wherein the groove is provided on the surface of the sintered ferrite plate opposite to the adhesive layer. The sintered ferrite substrate according to any one of claims 1 to 5, wherein the grooves are provided on both surfaces of the sintered ferrite plate.

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