JP2005080230A - Lc composite component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LC composite component whose strength is increased by increasing the mechanical strength. <P>SOLUTION: In the LC composite component 10 wherein a laminate provided with a coil part 16 for forming a coil conductor by laminating a plurality of sheet materials for forming an inner conductor to form a coil conductor and capacitor parts 14, 18 by laminating a plurality of sheet materials for forming an inner conductor to form a capacitor conductor, and formed by integrally baking them is provided with an external electrode connected to the coil conductor and the capacitor conductor, the capacitor parts 14, 18 are located beneath surface protection layers 13, 19 formed to both upper and lower faces of the layered body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an LC composite component including an inductor and a capacitor that function as a filter for removing noise such as electronic equipment.

There is known an LC composite component that is used as a filter for removing noise from an electronic device or the like and has a monolithic structure by combining an inductor (coil portion) and a capacitor (capacitor portion).
Conventionally, this type of LC composite component is composed of an inductor and a capacitor formed by forming a conductor on the surface of a mixed material of a dielectric material and a magnetic material and laminating them. In this case, the layer in which the conductive film (internal conductor) serving as the inductor and the capacitor is formed is arranged in the intermediate layer of the multilayer body.

In a conventional chip-type electronic component, ceramics are placed in the vicinity of the upper and lower surfaces of the electronic component body (laminated body) (side surfaces extending in the direction connecting the end surfaces provided with the terminal electrodes) in a direction parallel to the upper and lower surfaces. It has been proposed to improve the fracture resistance of the electronic component body, which is a ceramic sintered body that is weak against tensile stress, by providing a compressive stress applying layer made of a material having a larger thermal expansion coefficient than the sintered body. . (For example, see Patent Document 1)
JP-A-9-134304

However, in conventional LC composite parts, if the material of the upper and lower surface layers itself is not strong enough and is weak, mechanical strength such as thermal stress and bending stress due to temperature change may be insufficient, and reliability and durability There is a concern that inconvenience will occur in terms of sex.
The present invention has been made in view of the above circumstances, and has as its main object to provide an LC composite component having increased mechanical strength and increased strength.

The present invention employs the following means in order to solve the above problems.
The LC composite component according to the present invention includes a coil portion that forms a coil conductor by laminating a plurality of sheet-like materials that form internal conductors, and a capacitor that forms a capacitor conductor by laminating a plurality of sheet-like materials that form internal conductors And a laminated body formed by integrally firing these parts, and external electrodes connected to the coil conductor and the capacitor conductor are provided on both upper and lower surfaces of the laminated body. The capacitor portion is arranged immediately below the surface protective layer to be formed.

According to such an LC composite component, since the capacitor portion is disposed immediately below the surface protective layer formed on the upper and lower surfaces of the laminate, the large-area internal conductor that is a high shrinkage layer is adjacent to the surface protective layer. It will be laminated in the position. Such a high shrinkage layer functions as a compressive stress applying layer, so that the strength of the LC composite component can be increased.
In addition, it is desirable that the surface protective layer is made of a highly shrinkable material made of a nonmagnetic insulating material, and a compressive stress applying layer is formed together with the above-described dielectric material layer.

  Further, in the above LC composite component, it is preferable to provide a stray capacitance reducing layer between the capacitor portion and the coil portion, thereby reducing stray capacitance between the capacitor portion and the coil portion. High frequency characteristics can be improved.

According to the LC composite component of the present invention, since the compressive stress applying layers are formed on the upper and lower surfaces of the laminate, it is possible to provide a product with increased mechanical strength and increased strength.
In addition, since the stray capacitance reduction layer is provided to reduce stray capacitance between the capacitor portion and the coil portion, a product with excellent noise removal characteristics can be obtained by improving the high frequency characteristics of the LC composite component.

  Hereinafter, an embodiment of an LC composite component according to the present invention will be described with reference to the drawings. The present embodiment is applied to a two-terminal type noise filter. FIG. 1 is an exploded perspective view of the LC composite component in the present embodiment, and FIG. 2A is an LC composite component showing the completed state of FIG. FIG. 2B is an equivalent circuit diagram of the LC composite component, and FIG. 3 is an AA cross-sectional view of the laminate shown in FIG.

1 to 3, the LC composite component 10 has a structure in which a plurality of sheet-like materials made of a mixed material of a magnetic material and a dielectric material are stacked and integrated. In addition, two external electrodes 11 and 12 connected via three lead conductors and lead electrodes, which will be described later, are distributed on two opposing side surfaces of the LC composite component 10 formed as a substantially rectangular parallelepiped laminate. Is provided.
In the configuration example shown in FIG. 1, the first surface protective layer 13, the first capacitor unit 14, the first stray capacitance reducing layer 15, the coil unit 16, and the second stray capacitance are sequentially formed from the top of the LC composite component 10 that is a laminated body. A reduction layer 17, a second capacitor portion 18, and a second surface protective layer 19 are disposed.

The first surface protective layer 13 and the second surface protective layer 14 are sheet-like highly shrinkable materials disposed on the upper and lower surfaces of the laminate, and are compressed together with the inner conductors of the first and second capacitor portions 14 and 18 described later. A stress applying layer is formed. As the sheet-like material for the first surface protective layer 13 and the second surface protective layer 19, for example, the material A shown in Table 1 is employed.
When the material composition of the material A is seen, the ratio of glass (wt%) is considerably increased, while the ratio of magnetic substance and dielectric is relatively small, and therefore the magnetic permeability and dielectric constant are small. It is a non-magnetic insulating material having (low) material properties.

  The 1st capacitor | condenser part 14 and the 2nd capacitor | condenser part 18 are comprised by the two sheet-like materials 14a and 14b and 18a and 18b by which each was laminated | stacked. By forming large-sized internal conductors 31, 32, 33, and 34 on the surface of each sheet-like material 14a, 14b and 18a, 18b, the two internal conductors are arranged to face each other. Thus, two sets of capacitors independent of each other are formed. The internal conductor 31 has an extraction electrode 31 a electrically connected to the external electrode 11, the internal conductor 32 has an extraction electrode 32 a electrically connected to the external electrode 12, and the internal conductor 33 has an external electrode 11. A lead electrode 33a that is electrically connected to the external electrode 12 and a lead electrode 34a that is electrically connected to the external electrode 12 are provided integrally and continuously on the inner conductor 34, respectively.

For example, the material B shown in Table 1 is used for the sheet-like materials 14a, 14b, 18a, and 18b of the first capacitor portion 14 and the second capacitor portion 18 as described above. Moreover, the material C shown in Table 1 is employ | adopted for the material of the internal conductors 31-34.
Here, looking at the material composition of material B, glass is not included at all, as opposed to material A, and the magnetic substance and dielectric ratio (wt%) is relatively high. In addition, the magnetic material has a material characteristic having a large (high) dielectric constant.
Further, looking at the material composition of the material C, 100% is a conductive metal (for example, silver), and the internal conductors 31 to 34 made of such a conductor are formed by a known printing method. .

The first stray capacitance reducing layer 15 and the second stray capacitance reducing layer 17 are made of a sheet-like material B having no internal conductor in multiple layers (in order to increase the thickness between the capacitor portions 14, 18 and the coil portion 16). In the example shown in FIG. In this case, the material B uses a sheet-like material similar to that of the capacitor portions 14 and 18 described above. Therefore, the material B has a magnetic property having a large magnetic permeability and dielectric constant.
Note that the number of magnetic material layers forming the stray capacitance reducing layer is not limited to the illustrated five layers, and can be changed as needed.

The coil portion 16 is formed by stacking a plurality of internal conductors on the same material B as the capacitor portions 14 and 18 and the stray capacitance reducing layers 15 and 17 described above, thereby forming an internal conductor 40 having a coil shape as a whole. Is a layer. The illustrated coil portion 16 is configured by laminating sheet-like magnetic materials each formed with internal conductors 41 to 46 in six layers in the order of the first magnetic material 16a to the sixth magnetic material 16f.
The inner conductor 40 in this case is also made of a material 100% of the metal C shown in Table 1 and formed by a known printing method.

The inner conductor 41 of the first magnetic material 16a is formed in a substantially U shape with an extraction electrode 47 continuous at one end, and the other end is electrically connected to the lower layer inner conductor 42 through the through hole Ha. Yes. The lead electrode 47 is an internal conductor that is electrically connected to one end of the internal conductor 41 and led to a predetermined position (end) of the first magnetic material 16a. Finally, the end of the internal conductor 40 is connected to the above-described end. The external electrode 11 is electrically connected.
The inner conductor 42 of the second magnetic material 16 b is formed in a substantially U shape like the inner conductor 41. The inner conductor 42 is formed so as to be substantially symmetric with respect to the portion of the first inner electrode 41 excluding the lead electrode 47, and one end 42a thereof is electrically connected to the upper layer inner conductor 41 through the through hole Ha. ing. The other end of the inner conductor 42 is electrically connected to one end 43a of the inner conductor 43 formed in the lower third magnetic material 16c through the through hole Hb.

Similarly, the substantially U-shaped inner conductor 43 is electrically connected to one end 44a of the inner conductor 44 formed in the lower fourth magnetic material 16d via the through hole Hc, and is substantially U-shaped. The inner conductor 44 is electrically connected to one end 45a of the inner conductor 45 formed in the lower fifth magnetic material 16e through the through hole Hd, and the substantially U-shaped inner conductor 45 is formed through the through-hole Hd. It is electrically connected to one end 46a of the inner conductor 46 formed in the lowermost sixth magnetic material 16f through the hole He.
The inner conductor 46 is provided with an extraction electrode 48 that is electrically connected to the outer electrode 12 continuously to the substantially U-shaped inner conductor 46.
The number of laminated magnetic materials forming the coiled inner conductor 40 is not limited to the six layers described above, and can be changed as appropriate.

By laminating the nonmagnetic insulating material and the magnetic material in this way, the capacitor portions 14 and 18 are arranged above and below the coil portion 16 via the stray capacitance reducing layers 15 and 17, and further adjacent to the capacitor portions 14 and 18. Surface protective layers 13 and 19 are provided on both upper and lower end surfaces to form the LC composite component 10 with increased mechanical strength.
That is, the laminated body of the LC composite component 10 includes the surface protection layers 13 and 19 on both upper and lower surfaces and the inner conductors 31 to 34 directly below the floating capacitance reducing layers 15 and 17 serving as intermediate layers and the material B of the coil portion 16. Since the high-shrinkage material A and the material C are arranged and laminated, a compressive stress applying layer made of the high-shrinkage material is formed on the upper and lower surfaces. As a result, compressive stress formed by a high shrinkage material having a large shrinkage ratio due to firing of the laminate, such as when a thermal stress generated by a temperature change or an external bending stress acts on the LC composite component 10 The presence of the application layer can increase the mechanical strength. In other words, the lamination position is the surface so that the layers of the large-area inner conductors 31 to 34 that are indispensable for the two capacitor portions 14 and 18 constituting the LC composite component 10 can be effectively used for forming the compressive stress applying layer. The mechanical strength of the laminate is increased by placing the protective layers 13 and 19 directly below (immediately inside).

  Further, stray capacitance reduction layers 15 and 17 formed by laminating magnetic materials are arranged between the capacitor portions 14 and 18 and the coil portion 16 in order to reduce stray capacitance. If not considered, the magnetic material may be thin (for example, one sheet-like material). However, in order to improve the high-frequency characteristics and obtain excellent noise removal characteristics, it is preferable to provide a stray capacitance reducing layer having a sufficient thickness.

Next, the LC composite component 10 according to the present invention will be specifically described with reference to examples.
First, a magnetic material, a dielectric material, and a glass material were obtained as follows.
<Magnetic material>
NiO, ZnO, CuO, and Fe ₂ O ₃ were used as starting materials, and these were wet-mixed at a ratio of 15: 25: 12: 48 (molar ratio), respectively, and calcined at 950 ° C. to _obtain Ni _0.15 Zn _0. A magnetic material of ₂₅ Cu _0.12 Fe _0.96 O _1.96 was obtained. The obtained magnetic material was pulverized in a wet manner for 48 hours to obtain a spinel structure magnetic material having an average particle diameter of about 1 μm.

<Dielectric material>
PbO, La ₂ O ₃ , ZrO ₂ , TiO ₂ are used as starting materials, and these are wet-mixed at a ratio of 88: 6: 70: 30 (molar ratio), respectively, and calcined at 1050 ° C., and Pb _0.88 La A dielectric material of _0.12 Zr _0.7 Ti _0.3 O _3.06 was obtained. The obtained dielectric material was pulverized in a wet manner for 24 hours to obtain a perovskite type dielectric material having an average particle diameter of about 1 μm.
<Glass material>
In order to obtain a glass material in which the ratios of SiO ₂ , Al ₂ O ₃ , CaO, and BaO are 55: 15: 20: 10 (weight ratio), oxides and carbonic acid of each component of Si, Al, Ca, and Ba Salt or hydroxide was mixed, dissolved at 1100 ° C., and then rapidly cooled to obtain a glass material. The obtained glass material was pulverized for 48 hours in a wet manner to obtain a glass material having an average particle size of 0.5 to 1.5 μm.

Next, the magnetic material, the dielectric material, and the glass material are mixed at the composite ratios shown in Table 1, and 9.4 wt% of a binder such as polyvinyl butyral is added to the mixed powder to knead the composite paint. adjust. Using this composite paint, green sheets of material A and material B having a thickness of 10 to 50 μm were prepared by a doctor blade method.
Next, each green sheet is laminated, and on the way, each coil conductor and each capacitor conductor are printed and formed using a commercially available Ag paste (each coil conductor is connected through each through hole), and hot After crimping, the sintered body was cut to 1.0 × 0.5 mm after firing to obtain an LC composite part. The chip was degreased at 400 ° C. and then baked at 940 ° C. for 4 hours in the air. The obtained chip-shaped sintered body was chamfered by barrel polishing, and then a terminal electrode layer made of an Ag / Pd alloy was formed on both ends by dipping, followed by firing to obtain a two-terminal noise filter.

Material A shown in Table 1 is a sheet-like nonmagnetic insulating material used for the surface protective layers 13 and 19. The material composition of the material A is 20 wt% for the magnetic material, 13.3 wt% for the dielectric, and 66.7 wt% for the glass, and does not contain any metal.
A material B shown in Table 1 is a sheet-like material used as a magnetic material for the capacitor portions 14 and 18, the stray capacitance reducing layers 15 and 17, and the coil portion 16. The material composition of the material B is 60 wt% for the magnetic material, 40 wt% for the dielectric, 0 wt% for the glass, and does not contain any metal.
A material C shown in Table 1 is a conductive material used for the inner conductors 31 to 34 and 41 to 46. The material composition of the material C does not include magnetic material, dielectric material and glass at all, and the metal is 100 wt%.

The material characteristics of the materials A to C described above are the sintered body samples obtained by laminating green sheets of each material with a thickness of about 0.8 mm, press molding, and firing in the atmosphere at 940 ° C. for 4 hours. The characteristic results are shown in Table 1. Here, the magnetic permeability and the dielectric constant are measured values at a frequency of 1 MHz, and Δμ describes the ratio of the dielectric constant of another material with the dielectric constant of the material A as a reference (that is, 1).
As for the resistivity, ◯ is described as being highly insulating when it is 1 × 10 9 Ωcm or more.
Further, for shrinkage, the dimensions after firing are shown in percentage (%) based on the dimensions before firing.
That is, at both ends of the laminate, material A (shrinkage 84.0%) and material C (shrinkage 84.0%), which are high-shrinkage materials having a larger shrinkage than material B (shrinkage 84.4%) of the intermediate layer, are provided. Are arranged to form a compressive stress applying layer.

  By the way, the structure of this invention is not limited to embodiment mentioned above, For example, it can change suitably in the range which does not deviate from the summary of this invention, such as the internal conductor shape of a coil part, and the composition of material AC. it can.

It is a disassembled perspective view which shows one Embodiment of LC composite component which concerns on this invention. (A) is an external perspective view showing the LC composite component of FIG. 1, and (b) is an equivalent circuit diagram of the LC composite component. It is a schematic diagram which shows the AA cross section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 LC composite component 13 1st surface protection layer 14 1st capacitor | condenser part 15 1st stray capacitance reduction layer 16 Coil part 17 2nd stray capacitance reduction layer 18 2nd capacitor part 19 2nd surface protection layer 31-34, 40-46 Inner conductor

Claims (2)

A coil part that forms a coil conductor by laminating a plurality of sheet-like materials that form internal conductors and a capacitor part that forms a capacitor conductor by laminating a plurality of sheet-like materials that form internal conductors are integrated An LC composite component in which an external electrode connected to the coil conductor and the capacitor conductor is provided in a laminate obtained by firing in an automatic manner,
An LC composite component comprising the capacitor portion disposed immediately below a surface protective layer formed on both upper and lower surfaces of the laminate. The LC composite component according to claim 1, wherein a stray capacitance reducing layer is provided between the capacitor portion and the coil portion.

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