JP2002111421A - Noise filter - Google Patents

Abstract

(57) [Problem] To provide a noise filter capable of obtaining a large inductance without reducing capacitance by a simple and inexpensive method. SOLUTION: A noise filter 10 is formed by sequentially laminating a first inductor conductor 2, a dielectric layer 3a, a ground conductor 4, a dielectric layer 3b, and a second inductor conductor 5 on a surface of an insulating substrate 1. , One end 22 of the first inductor conductor 2 is connected to the other end 52 of the second inductor conductor 5, and the other end face of the insulating substrate 1 is connected to the other end 21 of the first inductor conductor 2. Terminal electrode 12, second external terminal electrode 15 connected to one end 51 of second inductor conductor 5, ground terminal electrode 1 connected to ground conductor 4
4 and a portion 13 that connects one end 22 of the first inductor conductor 2 to the other end 52 of the second inductor conductor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a noise filter for removing noise that enters electronic equipment and the like.

[0002]

2. Description of the Related Art A feedthrough capacitor is known as a conventional noise filter. The feedthrough capacitor is obtained by integrally laminating an insulating sheet having a through conductor and a ground conductor provided on the surface thereof, and protective sheets disposed above and below the insulating sheet. The through conductor has an inductance and a capacitance between itself and the ground conductor. In this feedthrough capacitor, when it is desired to increase the inductance without changing the component size, it is necessary to make the conductor width of the through conductor thin.

[0003] However, when the conductor width of the through conductor is reduced, the capacitance between the through conductor and the ground conductor decreases, which causes a problem that desired electric characteristics cannot be obtained.

Accordingly, as shown in FIGS. 3 and 4, insulating layers 33a, 33c,
33e and insulating layers 33b and 33d having ground conductors 34a and 34b provided on the surface thereof are alternately laminated to form a through conductor 32a.
Insulating layers 33a to 33b
e, the laminated noise filter 30 connected in series by the through holes 35a and 35b provided in Japanese Patent No. 30750.
No. 03. FIG. 3 is an external perspective view, and FIG. 4 is an exploded perspective view.

According to the same report, each through conductor 32a, 32
Since the ground conductors 34a and 34b are provided between the through-conductors 3 and 32c, the laminated noise filter 30
2a to 32c have their own inductances and the through conductors 32a, 32b, 32c and the ground conductors 34a,
Each has a capacitance between 34b. Each of the through conductors 32a, 32b, 32c is made of an insulating layer 33a-3.
Since they are connected in series by the through holes 35a and 35b provided in 3e, the conductor length of the through conductor is longer than that of the conventional through capacitor, and the inductance is larger than that of the conventional through capacitor. Also, the through conductors 32a to 32
c, the ground conductors 34a-34
The area facing b increases, thereby increasing the capacitance. Therefore, even if the conductor width of the through conductor is made smaller than that of the conventional noise filter in order to increase the inductance, the increased capacitance due to the longer conductor length compensates for the decreased capacitance due to the smaller conductor width.

[0006]

However, in manufacturing the above-described laminated noise filter 30, in order to connect the through conductors 32a to 32c in series, through holes 35a to 35b are formed in the insulating layers 33a to 33e. It is necessary to open. At the same time, the connection of the through conductors 32a to 32c is formed in the formation region of the ground conductors 34a to 34b, thereby reducing the facing area between the through conductors 32a to 32c and the ground conductors 34a to 34b. turn into. Also, the second external terminal electrodes 36, 3
In addition to 7, it is necessary to screen-print the ground terminal electrodes 38 from both sides of the laminate 31 to the mounting surface. For this reason, there has been a problem that the process is lengthened and the cost is increased.

[0007] Further, since it is manufactured using a green sheet laminating method, there is a limit to miniaturization and reduction in height.

The present invention has been devised in view of the above circumstances, and has as its object to provide a noise filter that can be easily reduced in size and height by a simple and inexpensive manufacturing method.

[0009]

In order to solve the above-mentioned problems, a noise filter according to the present invention comprises a first inductor conductor, a dielectric layer, a ground conductor,
A dielectric layer and a second inductor conductor are sequentially laminated, and one end of the first inductor conductor is connected to the second inductor conductor.
A first external terminal electrode connected to the other end of the first inductor conductor, and a second external terminal electrode connected to one end of the second inductor conductor. An external terminal electrode, a ground terminal electrode connected to the ground conductor, and a connection portion connecting one end of the first inductor conductor to the other end of the second inductor conductor are provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a noise filter according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an external perspective view of a noise filter according to the present invention. FIG. 2 is an exploded perspective view showing an electrode pattern of the noise filter of the present invention.

As shown in the figure, a noise filter 10 of the present invention includes a first inductor conductor 2, a thin film dielectric layer 3a, a ground conductor 4, a thin film dielectric layer 3b, The capacitor main body 10 is formed by laminating the two inductor conductors 5 respectively. The capacitor body is covered with a protective layer 6. Further, a first external terminal electrode 12 and a connection portion 13 are formed on one main surface of the insulating substrate 1, and a ground terminal electrode 14 and a second external terminal electrode 15 are formed on the other main surface.

The insulating substrate 1 is a heat-resistant insulating substrate such as alumina. On the front side of the insulating substrate 1, a first inductor conductor 2 having a spiral shape is formed. still,
The first inductor conductor 2 includes a lead portion 21 connected to the first external terminal electrode 12 and a lead portion 22 connected to the connection portion 13.

On the first inductor conductor 2, a dielectric layer 3a is formed. The dielectric layer 3 a is formed so as to expose the lead portions 21 and 22 of the first inductor conductor 2.

A ground conductor 4 is formed on the dielectric layer 3a.
Are formed so as to overlap with the entire portion of the first inductor conductor 2 except for the lead-out portion 21. The ground conductor 4 is drawn out by the lead-out portion 41 and is connected to the ground terminal electrode 14.

On this ground conductor 4, a dielectric layer 3b is formed. The dielectric layer 3a is formed so as to expose the lead portion 41 of the ground conductor 4.

On the surface side of the ground conductor 4, a spiral-shaped second inductor conductor 5 is formed. Note that the second inductor conductor 5 has a second external terminal electrode 15
And a lead portion 52 connected to the connection portion 13.

Further, the first inductor conductor, the ground conductor, the lead portions 21 to 22 of the second inductor conductor,
The protective layer 6 is formed on the whole except for 41 and 51 to 52.

Next, a method for manufacturing the noise filter 10 of the present invention will be described.

The insulating substrate 1 is formed of a multi-piece flat substrate having break lines formed in a predetermined size. After a large number of noise filters are formed on the substrate at once, the noise filters are individually formed along the lines. Divide into products. The substrate is not limited to alumina, and may be, for example, an insulating substrate having a laminated structure using glass ceramic mixed with glass and fired at a low temperature.

On the surface of the insulating substrate 1, a conductive paste such as Ag-Pd or Ag-Pt is printed as a first inductor conductor 2 on a predetermined pattern substrate and dried.
Alternatively, Ag, Pt, Au, Cu, Ni, or the like may be used as the electrode material. The first inductor conductor 2 has a spiral shape, and a part of the first inductor conductor 2 is drawn out in two directions to near one end of the insulating substrate 1, and each of the drawing part 21 and the connecting part is connected to the first external terminal electrode 12. 13 are connected to the drawer 22.

The dielectric layer 3a is formed on the first inductor conductor 2
The dielectric paste is printed by a screen printing method so as to cover the substrate, and dried. The layer thickness is, for example, 5 to 50 μm. As the dielectric paste, a powder of a lead relaxer material or a titanium-based material is used, which is mixed with an organic vehicle to form a paste. Some glass may be added to enhance sinterability.

The ground conductor 4 is formed by screen-printing the same conductive paste as the first inductor conductor 2 on the unfired dielectric film 3a. The electrode pattern has a predetermined facing area so that a capacitor can be formed facing the first inductor conductor 2. One end of the electrode pattern forms a lead portion 41 connected to the ground terminal electrode 14.

The dielectric layer 3b is printed with the same dielectric paste as the dielectric layer 3a by a screen printing method so as to cover the ground conductor 4, and dried.

The second inductor conductor 5 is formed by forming the same conductive paste as the first inductor conductor 2 and the ground conductor 4 on the unfired dielectric film 3b by a screen printing method. The electrode pattern has a spiral shape and has a predetermined facing area so that a capacitor can be formed facing the ground conductor 4. One end of the electrode pattern is pulled out to the vicinity of both ends of the insulating substrate 1 and is connected to the second external terminal electrode 15.
And a lead-out portion 52 connected to the terminal. Then, the electrode pattern is dried.

Next, the entirety of the second inductor conductor 5 and the dielectric layer 3b is covered, and the first inductor conductor, the ground conductor, and the lead portions 21 to 2 of the second inductor conductor are provided.
A glass paste made of crystallized glass or amorphous glass is printed so as to expose 2, 41, 51 to 52,
Perform baking processing. As a result, the protective layer 6 on the surface is formed on the second inductor conductor 5.
The protective layer 6 desirably has a two-layer structure of a crystallized glass layer and an amorphous glass layer, each having a thickness of, for example, about 20 μm.

Next, the first inductor conductor 2, the dielectric layer 3a, the ground conductor 4, the dielectric layer 3b, the second inductor conductor 5, and the protective layer 6 are simultaneously fired. The firing temperature is about 9
00 ° C.

Thereafter, the large-sized insulating substrate is divided and cut for each predetermined element region.

Next, at one end of the element, the first external terminal electrode 12 connected to the lead portion 21 of the first inductor conductor 2, the lead portion 22 of the first inductor conductor 2, and the second inductor conductor The connection part 13 connected to the lead-out part 52 of No. 5 is formed by printing and baking a conductive paste. Further, a second external terminal electrode 15 connected to the lead portion 51 of the second inductor conductor 5 and a ground terminal electrode 14 connected to the lead portion 41 of the ground conductor 4 are connected to the other end of the element by conductive paste. It is formed by printing and baking. As a result, FIG.
Is obtained.

The noise filter 10 having the above structure
Are the first inductor conductor 2 and the second inductor conductor 5
Have a spiral shape and are connected in series by the connection portion 13, so that the first and second inductor conductors 2,
5, the total conductor length is longer than the conventional noise filter,
A large inductance L is obtained. Further, since the conductor lengths of the first and second inductor conductors 2 and 5 are increased, the area facing the ground conductor 4 is increased, thereby increasing the capacitance. Therefore, even if the conductor width of the first and second inductor conductors 2 and 5 is made narrower than that of the conventional noise filter in order to increase the inductance L of the noise filter 1, the capacitance that increases due to the increase in the conductor length still remains. Compensate for the reduced capacitance due to the reduced conductor width.

Further, since the first and second inductor conductors 2 and 5 are connected in series at the connection portion 13, there is no need to make a through hole in the insulating layer. Also, the terminals 12 to 15 need only be formed on the two surfaces. Therefore, the process is simplified, and the cost can be reduced.

Further, since it is manufactured using the thick film method, it is possible to realize a reduction in size and height.

Here, as shown in FIGS. 1 and 2, a first external terminal electrode 12 and a connection portion 13 are formed on one end surface of a pair of substrate 1 end surfaces facing each other, and a second external terminal is formed on the other end surface. By forming the electrode 15 and the ground terminal electrode 14, the mounting becomes symmetric during mounting, so that stable mounting becomes possible.

Furthermore, when the large insulating substrate is divided and cut into predetermined element regions, the intervals between the lead portions exposed on the end surfaces become uniform, so that it becomes a cutting shift detection mark.

Further, for example, the filter characteristics can be switched by connecting the first and second external terminal electrodes 12 and 15 to the input side and the connecting portion 13 to the output side.

The same plate making for screen printing of the first external terminal electrode 12 and the second external terminal electrode 15 and the plate making for screen printing of the ground terminal electrode 14 and the connection portion 13 can be used.

In the above-described embodiment, an example in which a dielectric material is used as the material of the insulator 3 has been described. However, a magnetic material or a combination thereof may be used. Examples of the magnetic material include those having ferromagnetic properties typified by a metal oxide magnetic layer such as Mn-Zn ferrite, Ni-Zn ferrite, and Mn-Mg-Zn ferrite.

The noise filter according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention.

For example, the first external terminal electrode 12 and the connection portion 13 are formed at the same end, but may be formed at different ends. Alternatively, the ground conductor is drawn only from one direction, but may be drawn from two or more directions. Further, the order of lamination of the first inductor conductor 2 and the second inductor conductor 5 may be reversed.

Although the above embodiment has been described with reference to the noise filter including a coil and a capacitor, the noise filter may further include a resistor. Alternatively, a plurality of noise filters may be arranged horizontally to form an array type.

[0041]

As apparent from the above description, according to the present invention, the first inductor conductor, the dielectric layer, the ground conductor, the dielectric layer, and the second inductor conductor are sequentially provided on the surface of the insulating substrate. A first inductor conductor connected to one end of the first inductor conductor, the other end of the first inductor conductor being connected to the other end of the second inductor conductor, An external terminal electrode, a second external terminal electrode connected to one end of the second inductor conductor, a ground terminal electrode connected to the ground conductor, and one end of the first inductor conductor are connected to the second inductor conductor. Since a portion to be connected to the other end is provided, the current that has entered the first inductor conductor from the first external terminal electrode flows through the connection portion to the second inductor conductor, and from the second external terminal electrode Come out To become.

For this reason, the conductor length of the through conductor is longer than that of the conventional noise filter, and a large inductance can be obtained. Therefore, as a result, the inductance can be increased without reducing the capacitance, and a noise filter having good electric characteristics can be obtained.

Further, the through conductors are connected in series at the connection portions, and there is no need to make through holes in the insulating layer. In addition, terminals need only be formed on two surfaces. Therefore, the process is simplified, cost can be reduced, and stability in mounting can be ensured.

Further, since it is manufactured using the thick film method, it is possible to realize a reduction in size and height.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a noise filter according to the present invention.

FIG. 2 is an exploded perspective view showing an electrode pattern of the noise filter of the present invention.

FIG. 3 is an external perspective view of a conventional laminated noise filter.

FIG. 4 is an exploded perspective view showing an electrode pattern of a conventional multilayer noise filter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 noise filter 1 insulating substrate 2 first inductor conductor 21, 22 lead portion 3 a, 3 b dielectric layer 4 ground conductor 41 lead portion 5 second inductor conductor 51, 52 lead portion 6 protective layer 12 first external terminal electrode DESCRIPTION OF SYMBOLS 13 Connection part 14 Ground terminal electrode 15 2nd external terminal electrode 30 Laminated noise filter 31 Laminated body 32a-32c Through conductor 33a-33e Dielectric layer 34a, 34b Ground conductor 35a-35b Through-hole conductor 36 First external terminal Electrode 37 Second external terminal electrode 38 Ground terminal electrode

Claims (1)

[Claims] 1. A first inductor conductor, a dielectric layer, a ground conductor, a dielectric layer, and a second inductor conductor are sequentially laminated on a surface of an insulating substrate, and one end of the first inductor conductor is connected to the first inductor conductor. Connected to the other end of the second inductor conductor, a first external terminal electrode connected to the other end of the first inductor conductor on an end face of the insulating substrate, and connected to one end of the second inductor conductor. A second external terminal electrode, a ground terminal electrode connected to the ground conductor, and a connection portion connecting one end of the first inductor conductor and the other end of the second inductor conductor. Noise filter.