JPH11186040A - Laminated noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorption type noise filter which can be manufactured easily on volume production basis. SOLUTION: This laminated noise filter includes a laminate 1 of plural laminated magnetic and conductor filters, the conductor filters being mutually connected to form an internal spiral conductor in a laminated-layer direction, terminal electrodes 4 provided on the laminate and connected to both ends of the internal conductor and to surround the internal conductor on the surface of the laminate, and a grounding electrode 3 provided on the laminate, so as not to make mutual be contact with the terminal electrodes. Thereby an absorption type laminated noise filter can be provided which can be easily and accurately manufactured on a volume production basis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated noise filter, and more particularly, to a multilayer internal conductor formed by laminating a plurality of magnetic layers and conductor pattern layers and connecting the conductor pattern layers to each other. The present invention relates to an absorption-type laminated noise filter formed of a laminate in which is formed.

[0002]

2. Description of the Related Art In recent years, various electronic devices have been reduced in size and weight.
With the demand for digitization and stricter regulations on noise, demand for a stacked noise elimination element is rapidly increasing. Also, the frequency of electronic devices has been rapidly increasing, such as the frequency of a clock in a CPU of a personal computer, and the necessity of removing noise up to a high frequency band has been increasing.

There are many types of noise removing elements such as beads and capacitors. In recent years, an absorption-type noise filter has been proposed as one that can obtain a greater noise removal effect.

FIG. 10 is a partially cutaway perspective view schematically showing the structure of a conventional absorption type noise filter. The conventional absorption-type noise filter shown in FIG. 10 includes a magnetic core 61 made of a magnetic material such as ferrite, a coil conductor 62 made of a metal wound around the magnetic core 61, and the outside of the magnetic core 61 and the coil conductor 62. It is composed of a magnetic body 63 such as a ferrite to cover, and a conductor electrode covering the outer periphery of the magnetic body 63.
A gap is formed in the conductor electrode that covers the outer periphery of the magnetic body 63, and is separated into the input / output terminal 64 and the ground electrode 65.

FIG. 11 shows a schematic equivalent circuit diagram of the absorption type noise filter of FIG. The so-called distributed constant line functions as a low-pass filter, and can accurately remove high-frequency noise.

A conventional method of manufacturing an absorption type noise filter having such a configuration includes a process of manufacturing a magnetic core 61,
A winding step of winding a coil conductor 62 around a magnetic core 61, a step of covering them with a magnetic body 63, a step of forming a conductor electrode on the outer periphery of the magnetic body 63, and forming a gap in the conductor electrode on the outer periphery of the magnetic body 63 by cutting or the like The step of performing

[0007]

However, such a conventional absorption type noise filter has a complicated structure and a large number of manufacturing steps. In particular, in the winding step, one coil is wound for each product. However, there is a problem that it is not suitable for mass production and the production cost is high. Also, it has not been easy to reduce the size of parts.

An object of the present invention is to provide an absorption-type noise filter which is easy to manufacture and suitable for mass production in view of such conventional problems.

Another object of the present invention is to provide an absorption type noise filter manufactured by a laminating method so as to be easily manufactured and suitable for mass production.

A further object of the present invention is to provide an absorption type laminated noise filter which can be reduced in size and weight.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, a multilayer noise filter includes a plurality of magnetic layers and a plurality of conductor pattern layers laminated, and the plurality of conductor pattern layers are laminated. A laminate in which internal conductors spiraling in the laminating direction are formed by being connected to each other, terminal electrodes provided on the surface of the laminate and connected to both ends of the internal conductor, and a surface of the laminate And a ground electrode provided so as to surround the internal conductor and not to contact the terminal electrode. Accordingly, the absorption type noise filter is provided, so that mass production of the absorption type noise filter can be easily and accurately performed. Further, it is easy to reduce the size and weight and is suitable for mounting on a wiring board.

According to the second aspect of the present invention, there is provided the first aspect.
Wherein the magnetic layer is formed of a printed magnetic layer or a magnetic sheet, and the conductor pattern layer is formed of a printed conductor pattern layer. Thereby, lamination can be performed easily and accurately.

According to the third aspect of the present invention, there is provided the first aspect of the present invention.
Or the multilayer noise filter according to 2, wherein the magnetic layer includes at least a low-insulating magnetic region portion and an insulating region portion, and the periphery of the internal conductor is a region including the insulating region portion. It is configured to be covered, and the periphery thereof is further covered with a region composed of the low-insulation magnetic material region. Thus, a magnetic material having low insulating properties can be used for the absorption type multilayer noise filter.

According to a fourth aspect of the present invention, in the laminated noise filter, a plurality of composite sheets each having a combination of a magnetic region portion and a conductor region portion are laminated, and at least a part of the conductor region portion is mutually connected. A laminated body on which an internal conductor spiraling in a direction parallel to the composite sheet is formed by connecting, a terminal electrode provided on a surface of the laminated body and connected to both ends of the internal conductor, respectively; On the surface of the body, so as to surround the inner conductor,
And a ground electrode provided so as not to contact with the terminal electrode. Accordingly, an absorption type noise filter is provided, so that mass production of the absorption type noise filter can be easily performed. Also,
The number of turns of the coil can be increased without increasing the number of layers in the stack. For this reason, manufacturing costs can be suppressed.

According to the fifth aspect of the present invention, in the fourth aspect,
In the multilayer noise filter according to the above, the terminal electrode is formed by connecting a part of the conductor region portion different from a portion forming the internal conductor to each other,
The ground electrode is formed by connecting portions of the conductor region different from the portions forming the internal conductor and the terminal electrode to each other.
Thereby, the labor for forming the terminal electrode and the ground electrode can be reduced, and the manufacturing cost can be suppressed.

Further, according to the invention described in claim 6, according to claim 4,
Or the laminated noise filter according to 5, wherein in the composite sheet, the magnetic region has low insulation properties and further has an insulator region, and the periphery of the internal conductor in the laminate is the insulating material. It is configured to be covered with a region composed of a body region portion, and the periphery thereof is further covered with a region composed of the low-insulation magnetic material region portion. Thus, a magnetic material having low insulating properties can be used for the absorption type multilayer noise filter.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laminated noise filter according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view showing the appearance of an absorption type multilayer noise filter according to an embodiment of the present invention, and FIG. 2 is a conceptual perspective view showing the internal structure thereof.

The absorption type noise filter of the absorption type shown in these figures is composed of a magnetic material 1 such as ferrite laminated and fired, an internal electrode 2 penetrating through the magnetic material 1 in a coil shape, and a magnetic material 1. It comprises a ground (GND) electrode or a ground electrode 3 provided on the outer periphery so as to surround the internal electrode 2, and input / output terminal electrodes 4 provided on the respective leading ends on both ends of the internal electrode 2. . The magnetic body 1 has a substantially rectangular parallelepiped shape, but may have other shapes. In FIG. 1, a hatched region is a region where a ground electrode or a terminal electrode is formed. The two terminal electrodes 4 are connected to both ends of the internal electrode 2, respectively.
A gap 5 is provided between the electrode and the ground electrode 3 to be insulated. The ground electrode 3 is grounded by, for example, being connected to a ground pattern or the like on the wiring board when the component is mounted on the wiring board, but may be connected to an AC power supply or the like in addition to the ground. is there.

FIG. 3 is a schematic equivalent circuit diagram of the laminated noise filter of FIG. By the so-called distributed constant line,
It functions as a low-pass filter and can accurately remove high-frequency noise. FIG. 1 having such a configuration
The method for manufacturing the laminated noise filter described above will be described with reference to the drawings.

FIGS. 4 and 5 are schematic explanatory views showing a first method for manufacturing the laminated noise filter of FIG. 1, in which FIG. 4 shows the substrate of the laminated noise filter, ie, the magnetic body 1 and the internal electrodes. FIG. 5 is a schematic explanatory view showing a method for manufacturing the portion 2 and FIG. 5 is a schematic explanatory view showing a method for forming the ground electrode 3 and the terminal electrode 4 of the multilayer noise filter.

As shown in FIG. 4, first, magnetic powder such as ferrite is used as a main raw material and kneaded with a resin or a solvent, and magnetic sheets 11 to 17 are formed by sheet molding or the like. Next, through holes 18 are formed at predetermined positions in the respective magnetic sheets 11 to 17 according to a desired coil pattern or the like. Next, each magnetic sheet 11
A predetermined conductive pattern 19 is formed by printing a conductive paste made of a metal such as Ag-Pd or Ag in accordance with a desired coil pattern or the like.

The magnetic sheets 11 to 17 on which the conductor patterns 19 are formed are replaced with magnetic sheets 11, 12,.
The layers are sequentially stacked and laminated in the order of No. 7, and pressurized by thermocompression or the like to produce a laminate. Alternatively, lamination of the magnetic sheets 11 to 17 in which the through holes 18 are not formed and in which the conductor patterns are not formed, and printing of the conductor patterns 19 may be alternately performed, and a laminate may be produced by applying pressure. The conductor pattern 19 on each magnetic material sheet is
8 to form a spiral coil as a whole. The obtained laminate is fired in a firing furnace at a predetermined temperature for a predetermined time and integrated to form a fired body. This makes it possible to obtain a base for the absorption type noise filter of the absorption type.

The number of sheets to be laminated can be any number, for example, 30 sheets, depending on the desired number of turns of the coil and the required thickness. Alternatively, a wide magnetic sheet may be used, and a single sheet may be formed with a conductor pattern in each of a large number of sections to produce a multilayer body including a large number. If this laminate is cut and baked, or if the laminate is baked and then cut, a large number of absorption-type laminated noise filter substrates can be manufactured at once. In addition to the sheet method, for example, it is also possible to manufacture a laminated body by alternately performing printing of a magnetic layer and printing of a conductor pattern by a screen printing method, and by firing, to manufacture a base of an absorption-type laminated noise filter. it can.

As shown in FIG. 5, the base of the laminated noise filter manufactured by the method shown in FIG. 4 is entirely covered with a conductor layer 20 such as a plating layer by electroless plating or the like.
Is formed. In the case of electroless plating, for example, electroless nickel plating, electroless copper plating, or the like can be used.
Next, the gap 5 is formed in the conductor layer 20 by, for example, irradiating a predetermined region of the conductor layer 20 with a laser. Thus, the separated and insulated ground electrode 3 and terminal electrode 4 can be formed. If a laser is used, the gap 5 can be accurately formed even if the component size is small. If the conductor layer 20 is a metal having a low melting point, the formation of the gap 5 by laser is easier. The gap 5 can be formed by machining other than laser, such as cutting by sandblasting or a slicer.

In addition to the method of forming a conductor layer over the entire surface of a substrate as shown in FIG.
For example, a conductor pattern corresponding to the ground electrode 3 and the terminal electrode 4 may be patterned on the substrate by a printing method, a transfer method, or the like, and then, if necessary, electroplating or the like may be performed to form the ground electrode 3 and the terminal electrode 4. .

FIG. 6 is a schematic explanatory view showing a second method for manufacturing the multilayer noise filter of FIG. First, the sheets 21 to 27 in which the magnetic region and the conductive region are combined in combination are produced. The shaded area in each of the sheets 21 to 27 shown in FIG. 6 is, for example, Ag-Pd
Conductor regions 31, 32 made of metal such as Ag or Ag,
A region 33 other than the hatched portion is a magnetic region 30 made of a magnetic material such as ferrite. Such a composite sheet can be produced, for example, by forming a slit in a magnetic sheet, embedding and printing a conductive paste in the slit, and cutting at a predetermined position.

The combination patterns of the magnetic regions and the conductive regions in each of the sheets 21 to 27 are different from each other. The sheets 21 and 27 correspond to the lower surface and the upper surface of the laminate to be manufactured, respectively, and are provided with a conductor region 32 for forming a ground electrode and a conductor region 33 for forming a terminal electrode. The sheets 22 and 26 are provided with a conductor region 32 and a conductor region 33 on the outer periphery. In the sheets 23 to 25, in addition to the conductor region 32 and the conductor region 33, a conductor region 31 for forming a coil-shaped internal electrode by lamination is further provided.

A predetermined number of such sheets 21 to 27 are sequentially laminated and pressed to produce a laminate. The number of layers of each sheet can be arbitrarily selected according to a required thickness, a desired coil shape, and the like. For example, by changing the number of sheets 24 as shown in FIG. 6, the size of the coil in the stacking direction can be adjusted. Also, by increasing the number of sheets 23 and 25, the thickness of the conductor layer forming the coil pattern can be increased, and the DC resistance of the internal electrodes can be reduced. As shown in FIG. 6, there are only five kinds of sheets (the sheets 21 and 27 and the sheets 22 and 26 have the same pattern), so that the design is easy and the sheet manufacturing process can be simplified.

FIG. 7A is a schematic perspective view showing the appearance of a laminate laminated by the method shown in FIG. 6, and FIG. 7B is a schematic perspective view of the laminate as viewed from above. is there. Inside the laminate, the conductor region 31 forms a coil,
The periphery is covered with a magnetic region 30. A conductor layer corresponding to the ground electrode and the terminal electrode is formed by conductor regions 32 and 33 on the outer peripheral portion of the laminate.

The thus obtained laminate is fired in a firing furnace at a predetermined temperature and for a predetermined time to obtain an integrated fired body, which is then subjected to electroplating or the like. A multilayer noise filter can be obtained. Ground electrode 3
In addition, since the step of forming the gap 5 for forming the terminal electrode 4 is not required, the manufacturing is easy and the cost of the product can be reduced.

Also, using a wide sheet, a combination pattern of a magnetic region and a conductor region may be formed in each of a large number of sections in one sheet, and these may be laminated to produce a laminate. . If this laminate is cut and baked, or if the laminate is baked and then cut and then subjected to electroplating or the like, a large number of absorption-type laminated noise filters can be manufactured easily and inexpensively at once.

When it is desired to increase the number of turns of the coil of the internal electrode, the pattern of the conductor region 31 in each sheet or each section of the sheet may be changed so that the coil pattern is formed more densely. Since it is not necessary to increase the number of sheets to be stacked, manufacturing costs can be reduced.

FIG. 8 is a schematic explanatory view showing a third method for manufacturing the laminated noise filter of FIG. 1, particularly when a magnetic material having low insulation such as metallic iron is used for the magnetic material. This is an effective method.

First, the sheets 42 to 42 in which a magnetic region having a low insulating property and an insulating region having a high insulating property are combined and combined.
46 is manufactured. The sheets 42 to 46 in FIG. 8 include a magnetic region 50 made of a low-insulating magnetic material such as metallic iron and an insulating region 51 made of a high-insulating ferrite or the like.

As in the first method described above, a through hole 52 is formed at a predetermined position on each sheet, and a conductor pattern 53 is formed at a predetermined position on each sheet. In the third method, a conductor pattern 53 is formed on the insulator region 51 of each sheet, and the laminate is sandwiched between the insulator regions 51 of the upper and lower sheets on which the conductor pattern 53 is laminated. To be Thereby, the internal electrode forming the coil can be covered with the insulator. The obtained laminate is the first
Similarly to the above method, firing is performed to form the ground electrode 3 and the terminal electrode 4.

As shown in FIG. 8, if the sheets 41 and 47 are made of the insulator region 51 so that the vicinity of the input / output terminals of the laminate is covered with a high insulator, the ground electrode can be formed. This is preferable because insulation between the terminal 3 and the terminal electrode 4 can be ensured.

FIG. 9 is a schematic sectional view of an absorption type laminated noise filter manufactured by the method shown in FIG. The periphery of the internal electrode 2 composed of the conductor pattern 53 is covered with an insulator layer 54 composed of an insulator region 51, and the periphery is further covered with a magnetic layer 55 composed of a low-insulation magnetic region 50. . The insulator layer 54 is also formed between the magnetic layer 55 and the terminal electrode 4. FIG. 9 (1)
As shown in FIG. 9B, the entire space between the internal electrodes 2 may be covered with the insulator layer 54. Alternatively, as shown in FIG.
May be covered with the insulator layer 54 only. Since the internal electrode 2 forming the coil is covered with the insulator layer 54, it is possible to secure insulation between the internal electrode 2 and the ground electrode 3 on the outer peripheral portion. A magnetic layer 5 is provided between the electrodes.
There is no conduction through 5. Therefore, it is possible to use a magnetic material having low insulation properties in the absorption type noise filter of the absorption type, and to obtain excellent absorption characteristics in a wide frequency band by using a ferrite resin having excellent high frequency characteristics in the insulating layer. Can be.

Further, a sheet obtained by combining the above-described second method and the third method and combining a magnetic layer having low insulating property, an insulating layer having high insulating property and a conductive layer in combination is used. An absorption type laminated noise filter can also be manufactured.

Although specific embodiments have been described, the present invention provides
Any absorption type noise filter manufactured by the lamination method may be used, and is not limited to the above-described embodiment. Although a laminated component or a chip component in which one element is incorporated has been described, a plurality of elements may be incorporated in one laminated component or a chip component. Further, the terminal electrodes of the respective elements can be made independent of each other and applied to an absorption type noise filter array.

[0040]

As described above, according to the first aspect of the present invention, it is possible to provide an absorption-type laminated noise filter that can be mass-produced easily and accurately. Further, it is easy to reduce the size and weight and is suitable for mounting on a wiring board.

According to the second aspect of the present invention, the lamination can be easily and accurately performed by the sheet method or the screen printing method, so that the production can be more easily performed.

According to the third and sixth aspects of the present invention, it is possible to use a magnetic material having a low insulating property for an absorption type multilayer noise filter.

According to the fourth aspect of the present invention, it is possible to provide an absorption-type multilayer noise filter that can be easily mass-produced and can increase the number of turns of a coil without increasing the number of layers in the layer. . Therefore, the cost of the product can be reduced.

According to the fifth aspect of the present invention, the labor for forming the terminal electrode and the ground electrode can be reduced.
Therefore, the number of manufacturing steps can be reduced, and the manufacturing cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an appearance of an absorption type multilayer noise filter according to an embodiment of the present invention.

FIG. 2 is a conceptual perspective view showing the internal structure of the multilayer noise filter of FIG.

FIG. 3 is a schematic equivalent circuit diagram of the multilayer noise filter of FIG. 1;

FIG. 4 is a schematic explanatory view showing a method of manufacturing a substrate in the first method of manufacturing the multilayer noise filter of FIG. 1;

FIG. 5 is a schematic explanatory view showing a method for manufacturing a terminal electrode and a ground electrode in the first method for manufacturing the multilayer noise filter of FIG. 1;

FIG. 6 is a schematic explanatory view showing a second method for manufacturing the multilayer noise filter of FIG. 1;

7 (1) is a schematic perspective view showing the appearance of a laminate laminated by the method shown in FIG. 6, and FIG. 7 (2) is a schematic perspective view of the laminate of (1) as viewed from above. .

FIG. 8 is a schematic explanatory view showing a third method for manufacturing the multilayer noise filter of FIG. 1;

FIG. 9 is a schematic cross-sectional view of an absorption type multilayer noise filter manufactured by the method shown in FIG. 8;

FIG. 10 is a partially cutaway perspective view schematically showing the structure of a conventional absorption noise filter.

FIG. 11 is a schematic equivalent circuit diagram of the absorption type noise filter of FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic body 2 Internal electrode 3 Ground electrode 4 Terminal electrode 5 Gap 11-17 Magnetic sheet 18 Through hole 19 Conductor pattern 20 Conductor layer 21-27 Sheet 30 Magnetic region 31 Conductor region (internal electrode formation) 32 Conductor region (Formation of ground electrode) 33 Conductor region (Formation of terminal electrode) 41 to 47 Sheet 50 Magnetic region 51 Insulator region 52 Through hole 53 Conductor pattern 54 Insulator layer 55 Magnetic layer 61 Magnetic core 62 Coil conductor 63 Magnetic material 64 I / O terminal 65 Ground electrode

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kuniho Watanabe 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation

Claims (6)

[Claims] 1. A laminate in which a plurality of magnetic layers and conductor pattern layers are laminated, and an inner conductor that draws a spiral in a lamination direction by connecting the conductor pattern layers to each other, and a surface of the laminate A terminal electrode provided on the surface of the laminate and surrounding the inner conductor, and a terminal electrode provided so as not to contact with the terminal electrode. A stacked noise filter, comprising: 2. The multilayer noise filter according to claim 1, wherein the magnetic layer is made of a printed magnetic layer or a magnetic sheet, and the conductor pattern layer is made of a printed conductor pattern layer. 3. The magnetic layer includes at least a low-insulating magnetic region portion and an insulating region portion, and a periphery of the internal conductor is covered with a region including the insulating region portion,
3. The device according to claim 1, wherein the periphery is covered with a region comprising the low-insulation magnetic material region.
2. The laminated noise filter according to 1. 4. A plurality of composite sheets each comprising a combination of a magnetic region portion and a conductor region portion are laminated, and at least a part of the conductor region portions are connected to each other to form a spiral in a direction parallel to the composite sheet. A laminated body on which an internal conductor to be drawn is formed; terminal electrodes provided on the surface of the laminated body and connected to both ends of the internal conductor, respectively; on the surface of the laminated body, so as to surround the internal conductor, and A ground electrode provided so as not to be in contact with the terminal electrode. 5. The terminal electrode is formed by connecting a part of the conductor region different from a portion forming the inner conductor to each other, and the ground electrode is formed by connecting the inner conductor and the conductor of the conductor region to each other. The multilayer noise filter according to claim 4, wherein the multilayer noise filter is formed by connecting portions different from the portions forming the terminal electrodes to each other. 6. The composite sheet, wherein the magnetic region has a low insulating property and further has an insulating region,
The peripheral portion of the internal conductor in the laminate is covered with a region including the insulator region portion, and the periphery thereof is further covered with a region including the low-insulation magnetic region portion. 6. The laminated noise filter according to 4 or 5.