JP6321950B2 - Inductance element - Google Patents

Description

  The present invention relates to an inductance element in which a coil is embedded in a magnetic core.

  An inductance element with a coil embedded in a magnetic core has a metal plate terminal exposed from the coil exposed on the outer surface of the magnetic core, and the metal plate terminal is usually connected to a land portion of an external circuit formed on the wiring board by soldering. Implemented.

  In a small inductance element, since the coil dimensions are small, the metal plate terminal that goes out of the magnetic core is also small, so that a sufficient connection area for soldering with an external circuit cannot be secured, and conduction reliability is improved. There arises a problem that the securing strength of the chip component on the substrate is lowered while it cannot be secured.

  In the chip component described in Patent Document 1 below, a coil is provided by winding a coated conductive wire around a winding groove of a drum core, and the drum core and the coil are covered with an insulating resin material. The coil is electrically joined to a metal plate terminal, and this metal plate terminal goes out from the side surface of the exterior resin made of an insulating resin material, and the tip is cut at the side surface end of the exterior resin. A conductive paste is applied to the entire side surface and the vicinity of the exterior resin, and the conductive paste is electrically coupled to the metal plate terminal.

  That is, the chip part described in Patent Document 1 is coated with a conductive paste that is electrically connected to the metal terminal over the entire side surface of the exterior resin, and this conductive paste is used as a substantial connection terminal part. We are trying to secure a large connection area necessary for soldering with the circuit.

JP-A-2-235305

  Since the chip component described in Patent Document 1 uses an epoxy resin or a diallyl resin as an insulating resin material constituting the exterior resin, when the material is heated for other purposes or in the usage environment of the chip component When the temperature becomes high, there is a problem that due to the deformation of the insulating resin material due to heat, the drum core covered with the exterior resin is stressed to be distorted, thereby causing a change in magnetic characteristics.

  Therefore, it is conceivable to use an insulating resin material that is less likely to be deformed by heat as the exterior resin. In this case, the conductive paste and the exterior may differ depending on the binder of the conductive paste that forms the connection terminal portion. The adhesiveness with the resin cannot be secured, the conductive paste is easily peeled off, the reliability of conduction with the external circuit cannot be secured, and the fixing strength of the chip component on the wiring board may be lowered.

  Accordingly, the present invention has stable magnetic characteristics by selecting a material for the coating resin layer so that a large stress does not act on the core body from the coating resin layer in the inductance element in which the coil is embedded in the magnetic core. An object is to provide an inductance element. Furthermore, an object of the present invention is to provide an inductance element that ensures the adhesion between the terminal conductive layer formed on the surface of the core body and the core body.

In order to solve the above-described problem, the inductance element according to the first aspect of the present invention is an inductance element in which a coil is embedded in a magnetic core, wherein the magnetic core includes a magnetic powder of an Fe-based amorphous alloy and a magnetic field. is pressure molding and a sexual core binder resin has a core body which binder resin for the magnetic core is thermally decomposed by annealing, a coating resin layer covering the outer surface of the core body, electrically connected to the coil At least a part of the metal terminal portion is exposed without being covered with the coating resin layer on the outer surface of the core body, and the terminal conductive material formed of the conductive material and the binder resin for the terminal conductive layer is formed on the surface of the magnetic core. A layer is formed, the terminal conductive layer is bonded to the covering resin layer and the terminal portion, and the covering resin layer is formed of an epoxy-modified silicone resin.

  By forming the coating resin layer that coats the outer surface of the core body of the magnetic core with epoxy-modified silicone resin, stable magnetic properties can be obtained without applying large stress to the magnetic core even if there is a temperature change. Furthermore, it is possible to ensure adhesion with the terminal conductive layer formed on the surface of the core body.

The inductance element of the second aspect of the present invention, in the inductance element has coils embedded in the magnetic core, the magnetic core comprises a binder resin for a magnetic powder and a magnetic core of an Fe-based amorphous alloy At least one of the metal terminal portions that have a core body that is pressure-molded by the thermal decomposition of the magnetic core binder resin by annealing and a coating resin layer that covers the outer surface of the core body and that is electrically connected to the coil. Is exposed without being covered with the coating resin layer on the outer surface of the core body, and a terminal conductive layer composed of a conductive material and a binder resin for the terminal conductive layer is formed on the surface of the magnetic core. Is bonded to the covering resin layer and the terminal portion, and the covering resin layer is formed of a phenol-modified alkyd resin.

  By forming the coating resin layer that covers the outer surface of the core body of the magnetic core with a heat-resistant polyester resin, even if there is a temperature change, a large stress is not given to the magnetic core, and stable magnetic properties can be obtained. Furthermore, adhesion with the terminal conductive layer formed on the surface of the core body can be ensured.

  In the inductance element of the first aspect, the epoxy-modified silicone resin preferably includes a silicone epoxy varnish.

In the inductance element of the present invention, the binder resin for the terminal conductive layer is preferably an epoxy resin.
Adhesion with the coating resin layer can be enhanced by using an epoxy resin.

  In the inductance element of the present invention, it is preferable that the terminal portion is a band-shaped body, and the surface of the band appears on the outer surface of the core body and is surface-bonded to the terminal conductive layer. By surface bonding, the bonding area between the terminal and the terminal conductive layer can be increased, and the bonding resistance can be reduced.

  According to the present invention, in the inductance element in which the coil is embedded in the magnetic core, the coating resin layer that covers the outer surface of the core body of the magnetic core is formed of the epoxy-modified silicone resin or the heat-resistant polyester resin, thereby changing the temperature. Even if it exists, the coating resin layer does not give a big stress to a magnetic core, and can provide the inductance element which has the stable magnetic characteristic. Furthermore, according to this invention, adhesiveness with the terminal conductive layer formed in the surface of a core main body can be ensured by forming a coating resin layer with an epoxy-modified silicone resin or a heat-resistant polyester resin.

It is a perspective view which shows the structure of the inductance element which concerns on embodiment of this invention. It is a bottom view which shows the structure of the inductance element of FIG. It is sectional drawing in the III-III line of FIG. 1, which shows the structure of the inductance element of FIG. FIG. 4 is a partial enlarged cross-sectional view in which a part of FIG. 3 is enlarged. It is a graph which shows the relationship between the material of a coating resin layer, and adhesive strength in an Example and a comparative example.

  Hereinafter, an inductance element according to an embodiment of the present invention will be described in detail with reference to the drawings.

  Hereinafter, an example in which the coil and the terminal portion are integrated will be described. However, the present invention can also be applied to a form in which the coil and the terminal portion are separate from each other.

  As shown in FIG. 1, the inductance element 1 of the present embodiment has a coil 10 embedded in a magnetic core 20. FIG. 1 shows the configuration of the inductance element 1 and is a perspective view in which the lower surface 22 of the magnetic core 20 faces upward. In FIG. 1, the coil 10 embedded in the magnetic core 20 is indicated by a solid line, and the outer surface of the magnetic core 20 is indicated by a dotted line.

  As shown in FIG. 1, the coil 10 is formed by winding a conductive strip 101 having a rectangular cross section around an oval around a center line O. The shape of the coil 10 is not limited to an ellipse, and may be a perfect circle, and can be appropriately selected by those skilled in the art.

  Both end portions 101a and 101a of the band-like body 101 forming the coil 10 are bent along a plane parallel to the central axis O, and the tip portions of the both end portions 101a and 101a are the lower surface 22 of the magnetic core 20. A pair of terminal portions 15 and 18 are formed by being bent so as to extend along the line. In the present embodiment, the coil 10 and the pair of terminal portions 15 and 18 are integrally formed. The band-like body 101 around which the coil 10 is wound is made of copper, for example.

  As shown in FIG. 4, the coil insulating layer 12 is formed on the surface of the strip 101. The coil insulating layer 12 has a two-layer structure in which, for example, a fusion layer such as nylon is superimposed on the surface of an insulating resin layer. In FIG. 4, it is shown that the coil insulating layer 12 is formed on the surface of the first terminal portion 15, but the other portions of the strip 101 have the same cross-sectional structure as the first terminal portion 15. The coil insulating layer 12 is formed on the surface.

  As shown in FIG. 1, the magnetic core 20 is formed in a substantially cubic shape. As shown in FIG. 3, the magnetic core 20 includes a core body 21 that is a compacted body obtained by pressure-molding magnetic powder and a binder resin, and a coating that covers the outer surface of the core body 21 and reinforces the core body 21. And a resin layer 22.

  As shown in FIGS. 1, 2, and 3, the band surfaces 15 a and 18 a of the first terminal portion 15 and the second terminal portion 18 are the lower surface 21 a of the core body 21 (the lower surface of the magnetic core 20). It is exposed and is substantially flush with the lower surface 21a of the core body 21. Further, both end portions 101 a of the band-like body 101 extending from the coil 10 to the first terminal portion 15 and the second terminal portion 18 are also substantially flush with the side surface 21 b of the core body 21.

  As shown in FIGS. 3 and 4, the terminal portions 15 and 18 are disposed in a recess 22 b having substantially the same shape as the terminal portion formed on the lower surface 21 a of the core body 21. The recess 22b is formed, for example, in a compacting process in a state where the coil 10 and the terminal portions 15 and 18 are disposed inside the cavity (not shown), and the magnetic core material (magnetic powder supplied to the inside of the cavity). And a binder resin) with a constant pressure and heating.

  As shown in FIG. 4, the coil insulating layer 12 is not formed on the tip surfaces 15 b and 18 b of the terminal portions 15 and 18. This is because the tip surfaces 15b and 18b correspond to the cut surface when the coated conductor is cut.

  As shown in FIG. 4, a gap 25 is formed between the tip surfaces 15 b and 18 b of the terminal portions 15 and 18 and the stepped portion 21 c of the core body 21. The gap 25 is formed due to a spring back or the like after the terminal portions 15 and 18 are pressed in the compacting process.

  As shown in FIGS. 3 and 4, the entire outer surface of the core body 21 is coated with a coating resin layer 22. As shown in FIG. 4, a part of the coating resin layer 22 is also filled in the gap 25. The first terminal portion 15 and the second terminal portion 18 are covered with the first terminal portion 15 and the second terminal portion 18 because the band surfaces 15a and 18a are exposed on the lower surface 21a of the core body 21. The resin layer 22 is surface-bonded.

  As shown in FIG. 2, a pair of terminal conductive layers 42 are formed on the lower surface of the magnetic core 20 with an interval in the horizontal direction in the figure. The terminal conductive layer 42 is formed in a strip shape on the outer surface of the coating resin layer 22 that covers the lower surface of the magnetic core 20. As shown in FIGS. 2, 3, and 4, a hole 43 is formed in the covering resin layer 22 at a portion overlapping the terminal portions 15 and 18, and the terminal portions 15 and 18 are covered. The coil insulating layer 12 is also removed at a portion corresponding to the hole 43. The terminal conductive layer 42 is joined and electrically connected to the band surfaces 15 a and 18 a of the terminal portions 15 and 18 in the hole 43. Since the terminal portions 15 and 18 and the terminal conductive layer 42 are surface bonded, the bonding resistance is reduced, and the terminal portions 15 and 18 and the terminal conductive layer 42 are also firmly bonded.

  The terminal conductive layer 42 is formed in a band shape over the entire length of this side portion (the entire length in the vertical direction in the figure) on both the left and right sides in FIG. 2, and the area of the terminal portions 15 and 18 located on the lower surface of the magnetic core 20 Compared with FIG. 2, the area of the terminal conductive layer 42 is sufficiently large. Most of the terminal conductive layer 42 is bonded to the surface of the coating resin layer 22, and only a part of the terminal conductive layer 42 is bonded to the band surfaces 15 a and 18 a of the terminal portions 15 and 18 in the hole 43.

  The terminal conductive layer 42 is composed of a conductive material and a binder resin. The binder resin of the terminal conductive layer 42 is, for example, an epoxy-based resin, and the conductive material is made of, for example, silver, and is specifically formed using a silver paste or the like.

  Here, it is possible to secure an area necessary for soldering by forming the terminal portions 15 and 18 extended from the coil 10 without forming the terminal conductive layer 42 made of silver paste or the like. When the terminal portions 15 and 18 are enlarged, when the terminal portions 15 and 18 are bent on the outer surface of the magnetic core 20, the force acting on the magnetic core 20 from the terminal portions 15 and 18 becomes too large, and the magnetic core 20 is cracked. It is easy to break. In the case where the magnetic core 20 is a compacted core formed of magnetic powder and a binder resin, it is easy to damage the magnetic core 20 when a large force is applied thereto, and each side has a dimension of about 1 to 2 mm. When a small size is formed, the magnetic core 20 is particularly easily damaged.

  As shown in FIG. 3 and FIG. 4, it is necessary to form a recess 22b for arranging the terminal portions 15 and 18 on the outer surface of the magnetic core 20, but when the terminal portions 15 and 18 become longer, the recess 22b It is necessary to secure a large area. Since there is no magnetic powder in the recess 22b, if the recess 22b is widened, the volume occupied by the magnetic powder of the magnetic core 20 is reduced, which causes a problem that the inductance cannot be increased.

  In the present embodiment, by forming the terminal conductive layer 42 with silver paste or the like, even if the length and area of the terminal portions 15 and 18 extended from the coil 10 are small, the soldering area with the external circuit is widened. It can be secured. Since the terminal portions 15 and 18 can be made small, the force applied to the magnetic core 20 can be reduced when the terminal portions 15 and 18 are formed, and the magnetic core 20 is hardly damaged. Moreover, since the recessed part 22b can be made small, the fall of the inductance of the magnetic core 20 can be prevented.

  Further, even if the areas of the terminal portions 15 and 18 are small, as shown in FIG. 2, the terminal conductive layer 42 having a large area can be formed over the entire length of both sides of the lower surface of the magnetic core 20, so that the external circuit and The reliability of conduction of the inductance element 1 can be improved, and the fixing strength of the inductance element 1 on the wiring board can be increased. Therefore, it is optimal when a small dust-molded core having a side dimension of about 1 to 2 mm is employed.

  The core body 21 is a dust-molded core formed by pressing magnetic powder and a binder resin in the cavity in a state where the coil 10 is installed in the cavity of the molding die. The magnetic powder is a magnetic alloy powder, for example, an Fe-based amorphous alloy powder mainly composed of Fe and containing various metals such as Ni, Sn, Cr, P, C, B, Si, and water atomization. Powdered by the method. The binder resin is an acrylic resin, a silicone resin, an epoxy resin, or the like.

  The covering resin layer 22 is an electrically insulating resin layer and is formed of an epoxy-modified silicone resin or a heat-resistant polyester resin. For example, a silicone epoxy varnish is used as the epoxy-modified silicone resin. As the heat-resistant polyester resin, for example, phenol-modified alkyd resin or polyester silicone is used. Further, it is preferable that the coating resin layer 22 has a viscosity capable of impregnating the outer surface of the magnetic core 20. By impregnating the coating resin layer 22 from the outer surface of the core body 21 to a predetermined depth, the mechanical strength of the surface of the core body 21 of the green compact can be reinforced by the coating resin layer 22 after curing.

  As the magnetic powder, an Fe-based amorphous alloy is preferably used. In this case, the core body 21 is preferably molded and then annealed at a temperature of several hundred degrees C to remove the magnetostriction. However, in the annealing step, the core body 21 is thermally decomposed due to thermal decomposition of the binder resin. Tends to be brittle. Therefore, the coating resin layer 22 is particularly necessary for a dust-molded core that requires annealing.

  When the coating resin layer 22 covering the outer surface of the core body 21 is formed of epoxy-modified silicone or heat-resistant polyester resin, excessive stress and strain are applied from the coating resin layer 22 to the core body 21 even if there is a temperature change. Without being given, the magnetic properties of the core body 21 can be stabilized.

  Furthermore, the adhesion between the coating resin layer 22 and the terminal conductive layer 42 is enhanced by forming the coating resin layer 22 from epoxy-modified silicone or heat-resistant polyester resin and using an epoxy resin as the binder resin used for the terminal conductive layer 42. Can do.

Examples will be described below.
Example 1
Coating resin layer: Silicone epoxy varnish (modified silicone resin) ES-1001N (manufactured by Shin-Etsu Chemical Co., Ltd.)
Solvents (xylene, butanol, diacetone alcohol) were added to dilute to a viscosity of 10 mPa · s.
Curing conditions: After drying at 70 ° C. for 30 minutes, it was cured by heating at 200 ° C. for 45 minutes.

(Example 2)
Coating resin layer: Silicone epoxy varnish (modified silicone resin) ES-1023 (manufactured by Shin-Etsu Chemical Co., Ltd.)
A solvent (xylene, diacetone alcohol) was added to dilute to a viscosity of 200 mPa · s.
Curing conditions: After drying by heating at 70 ° C. for 30 minutes, the coating was cured by heating at 200 ° C. for 45 minutes.

(Example 3)
Coating resin layer: Silicone polyester varnish (polyester silicone) KR-5230 (manufactured by Shin-Etsu Chemical Co., Ltd.)
A solvent (propylene glycol monomethyl ether acetate: PGMAC) was added and diluted to a viscosity of 300 mPa · s.
Curing conditions: After heating at 70 ° C. for 20-30 minutes to dry, it was cured by heating at 200 ° C. for 45 minutes.

Example 4
Coating resin layer: heat-resistant polyester resin (phenol-modified alkyd resin) H550 (manufactured by Meiden Chemical Co., Ltd.)
A solvent (xylene) was added to dilute to a viscosity of 350 mPa · s.
Curing conditions: After drying by heating at 135 ° C. for 60 minutes, it was cured by heating at 180 ° C. for 150 minutes.

(Example 5)
Coating resin layer: Silicone-modified epoxy varnish TSR194 (made by Momentive Performance Materials Japan)
Solvents (xylene and ethylbenzene) were added to dilute to a viscosity of 180 mPa · s.
Curing conditions: After heating at 70 ° C. for 20-30 minutes to dry, it was cured by heating at 150 ° C. for 30 minutes.

(Comparative Example 1)
Coating resin layer: Methylphenyl silicone resin (straight silicone resin) KR-271 (manufactured by Shin-Etsu Chemical Co., Ltd.)
A solvent (xylene) was added to dilute to a viscosity of 180 mPa · s.
Curing conditions: After drying by heating at 70 ° C. for 30 minutes, heating was performed at 250 ° C. for 60 minutes for curing.

(Comparative Example 2)
Coating resin layer: methyl silicone resin (straight silicone resin) KR-242A (manufactured by Shin-Etsu Chemical Co., Ltd.)
A solvent (toluene, isopropyl alcohol) was added to dilute to a viscosity of 12 mPa · s.
Curing conditions: After heating at 70 ° C. for 30 minutes to dry the solvent, it was cured by heating at 200 ° C. for 35 minutes.

(Comparative Example 3)
Coating resin layer: Two-pack type epoxy adhesive AZ15 (main agent): HZ15 (curing agent) = 100: 30 (manufactured by Nagase ChemteX Corporation)
Curing conditions: After drying at 70 ° C. for 20 to 30 minutes to dry the solvent, it was cured by heating at 180 ° C. for 60 minutes.

  About the above sample, the adhesive strength and the inductance change rate (L change rate) were measured.

<Adhesive strength>
The sample used for the test is a brush covering the entire upper surface of the copper plate (thickness 0.1 mm × width 25 mm × length 100 mm) corresponding to the terminal portions 15 and 18 with a brush. Two samples are prepared by applying a terminal conductive layer corresponding to the terminal conductive layer 42 with a brush with a size of 25 mm wide × 12.5 mm long, and the terminal conductive layers of the two samples are connected to each other. It was produced by contacting and curing each other.

  Here, as the terminal conductive layer, silver paste H9108 (binder: epoxy resin) (manufactured by NAMICS) was used and cured by heating at 175 ° C. for 1 hour.

  The adhesive strength was measured using a tensile tester (Model No. 3365 (Instron)) under the condition No. 15 (tensile shear).

  FIG. 5 is a graph showing the relationship between the material of the coating resin layer and the adhesive strength in Examples and Comparative Examples. The adhesive strength referred to here is the tensile strength (maximum load at break of shear) (unit MPa) measured with the tensile tester. The measurement was performed three times, and the average value (unit MPa) shown below was displayed in FIG.

Example 1: 0.825
Example 2: 0.961
Example 3: 1.194
Example 4: 1.359
Comparative Example 1: 0.324
Comparative Example 2: 0.784

  From this result, in Examples 1 to 4, the adhesive strength was 0.8 Mpa, and sufficient adhesion between the coating resin layer and the terminal conductive layer could be confirmed. On the other hand, in Comparative Examples 1 and 2, the adhesive strength is less than 0.8, and when a straight silicone resin is used for the coating resin layer and an epoxy resin is used for the binder resin of the terminal conductive layer, It was found that sex could not be secured.

  Further, in visual inspection, in Comparative Example 1, interface peeling occurred between the coating resin layer and the terminal conductive layer, and in Comparative Example 2, the coating resin layer was easily peeled from the copper plate.

<Inductance change rate>
Preparation of sample: Coil using magnetic powder made of Fe-based amorphous alloy having composition of Fe _71.4 Ni ₆ P _10.8 C _7.8 B ₂ Cr ₂ and binder resin (acrylic resin) A core body with embedded material was created. Regarding the dimensions, the width dimension corresponding to the longitudinal direction of the terminal conductive layer was 0.6 mm, the width dimension orthogonal to this was 2 mm, and the thickness dimension was 0.04 mm. The width dimension of the terminal conductive layer was 0.6 mm, and the contact area between the terminal conductive layer and the terminal portion was 0.12 mm ² or more.

  The coil had a width of the strip-shaped conductor of 0.28 mm, a thickness of 0.03 to 0.1 mm, and a number of turns of 3.5 to 14.5.

  Measuring method: Current is applied to the coil of the inductance element composed of the coil and the core body, 0.5 mA is measured immediately after the initial inductance measured by the LCR meter is L0, and the core body is covered with the respective coating resin layers. Let L1 be the measured inductance after leaving the inductance element covered with the coating resin layer at 60 ° C. in an environment with a relative humidity of 95% for 300 hours.

L1 / L0 × 100 (%) was defined as coat deterioration, and L2 / L1 × 100 (%) was defined as moisture resistance deterioration.
(1) Coat deterioration Example 1: -4%
Example 5: -3%
Comparative Example 3: -16%
(2) Moisture resistance deterioration Example 1: -2%
Example 5: -6%
Comparative Example 3: -8%
From the above results, it was found that in Examples 1 and 5, the change in inductance was sufficiently small in the coating deterioration test and the moisture resistance deterioration test, and the magnetic characteristics could be secured.

  Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and can be improved or changed within the scope of the purpose of the improvement or the idea of the present invention.

  As described above, the inductance element according to the present invention is useful in that an element having stable magnetic characteristics and high terminal conductive layer adhesion is realized.

DESCRIPTION OF SYMBOLS 1 Inductance element 10 Coil 12 Coil insulation layer 15, 18 Terminal part 15a, 18a Belt surface 20 Magnetic core 21 Core main body 21a Bottom surface 22 Covering resin layer 42 Terminal conductive layer 101 Band-shaped body

Claims (5)

In an inductance element in which a coil is embedded inside a magnetic core,
The magnetic core includes a magnetic powder and a binder resin for a magnetic core of an Fe-based amorphous alloy is pressure-molded, and the core body the magnetic core binder resin is thermally decomposed by annealing, the core A coating resin layer that covers the outer surface of the main body, and at least a part of the metal terminal portion that conducts to the coil is exposed without being covered by the coating resin layer on the outer surface of the core main body,
A terminal conductive layer composed of a conductive material and a binder resin for a terminal conductive layer is formed on the surface of the magnetic core, and the terminal conductive layer is bonded to the coating resin layer and the terminal portion,
The inductance element, wherein the coating resin layer is formed of an epoxy-modified silicone resin. In an inductance element in which a coil is embedded inside a magnetic core,
The magnetic core includes a magnetic powder and a binder resin for a magnetic core of an Fe-based amorphous alloy is pressure-molded, and the core body the magnetic core binder resin is thermally decomposed by annealing, the core A coating resin layer that covers the outer surface of the main body, and at least a part of the metal terminal portion that conducts to the coil is exposed without being covered by the coating resin layer on the outer surface of the core main body,
A terminal conductive layer composed of a conductive material and a binder resin for a terminal conductive layer is formed on the surface of the magnetic core, and the terminal conductive layer is bonded to the coating resin layer and the terminal portion,
An inductance element, wherein the coating resin layer is formed of a phenol-modified alkyd resin.   The inductance element according to claim 1, wherein the epoxy-modified silicone resin includes a silicone epoxy varnish.   4. The inductance element according to claim 1, wherein the terminal conductive layer binder resin is an epoxy resin.   The said terminal part is a strip | belt-shaped body, The belt | band | zone surface appears in the outer surface of the said core main body, The surface bonding of the said terminal conductive layer is any one of the Claims 1-4 characterized by the above-mentioned. The inductance element described in 1.

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