JP3314828B2 - Noise absorber and noise filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise absorber and a noise filter, and more particularly to a small noise filter.

[0002]

2. Description of the Related Art The relative permeability μ _r (f) of a magnetic material is expressed by the following equation.

Μ _r (f) = μ _r ′ (f) −j · μ _r “(f) where μ _r ′ corresponds to the effective relative magnetic permeability, μ _r ” corresponds to the loss, and j = ( -1) ^1/2 and f are frequencies.

A noise filter using a magnetic material utilizes a noise absorbing effect due to loss of the magnetic material, and is required to have a large impedance and resistance to noise. Therefore, the noise absorber | μ _r |. In and mu _r "is it necessary large electromagnetic environmental problems, for example, corresponds to a television broadcasting frequency 30 to 1000
MHz noise is regarded as a problem, and it is desired to realize a noise filter that exhibits an excellent noise absorbing effect in this frequency band.

FIG. 12 shows the frequency characteristics of typical relative magnetic permeability (μ _r ′ (0) = 1500) of a ferrite-based magnetic material which is a conventional material (see Junnosuke Uetano: “Electromagnetic Environment Engineering Information”, p. 152; (Published June 30, 1992, extra, Mimatsu Data System). Permeability μ of ferrite magnetic material
'between the (0) and the upper limit frequency f _c (μ _r "is defined at a frequency exhibiting a peak), mu _{r' r} (0) limits law holds a _{× f c = 5.6GHz (1)} , This is attributable to the fact that ferrite uses magnetic resonance loss as a magnetic substance loss (Toshinobu Kakuno: "Physics of Magnetic Material (Lower)" p.325, Shokabo). The dashed line in FIG. 12 shows the limit line of equation (1).
Equation (1) indicates that when the frequency characteristics of the ferrite-based magnetic material are set such that μ _r "is increased in a specific frequency band, the values of | μ _r | and μ _r " are uniquely determined. means. Therefore, there is no other way to increase the noise absorption effect than to increase the volume of the component, and there is a problem that the component size increases. FIG. 13 shows the shape of a noise filter using a ferrite-based magnetic material as a noise absorber, and FIG. 14 shows the frequency characteristics of its impedance. Here, the size of the noise filter is d = 10 mm, t
= 4 mm, a l = 30mm, | Z | impedance, R represents the resistance, X _L is the reactance. As a practical noise filter, an impedance of several tens Ω to about 100 Ω is required, and it can be seen from FIG. 14 that this condition is satisfied. However, the component size is considerably larger than other electronic components. ing.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned disadvantages, and an object of the present invention is to provide a higher performance noise absorber and a smaller noise filter.

[0007]

In order to solve the above-mentioned problems, a noise absorber according to the present invention comprises a non-magnetic insulator having a granular magnetic material having a grain size of 0.1 to 10 times the skin depth. Body 1
And are dispersed at intervals of 50 nm or more.

In the noise filter according to the present invention, one or more granular magnetic materials having a particle diameter of 0.1 to 10 times the skin depth are dispersed in the non- magnetic insulator at intervals of 50 nm or more. Characterized in that the noise absorber is formed in a cylindrical shape and wound one or more times.

[0009]

According to the present invention, since the noise absorbing effect due to the eddy current loss of the magnetic material can be efficiently used, a high-performance noise absorber and a small-sized noise filter can be realized.

The noise filter of the present invention is manufactured by forming a non-magnetic insulator on one or both sides of a film-like magnetic material, and winding the film-like magnetic material in a single or multiple layers. Alternatively, in a non-magnetic insulator, one or more granular magnetic substances having a particle size of 0.1 to 10 times the skin depth and a noise absorber dispersed at intervals of 50 nm or more are formed in a single or multiple cylindrical shapes. It is produced by stacking and winding.

[0011]

The present invention will be described in more detail with reference to the following examples.

(Embodiment 1) FIG. 1 is a view showing an embodiment of a noise filter according to the present invention, in which a magnetic body 1 as shown in FIG. (A)) or a structure in which the non-magnetic insulator 2 is bonded to both surfaces (FIG. 2 (b)), and the structure is formed by winding one or more layers in a cylindrical shape.

The structure shown in FIG. 2 is formed by ion beam sputtering (I
BS) method. The sputtering conditions were as follows: operating vacuum degree: 1 × 10 ⁻⁴ Torr (using Ar as a sputtering gas), acceleration voltage: 1 KV, and substrate temperature: 160 ° C.
As a target, a CoZr-based amorphous alloy (for example, CoZrNb [film composition: 87, 5, 8 at
%]), NiFe alloy (film composition: 82.5, 17.5a)
t%), SiO ₂ was used for the non-magnetic insulator, and glass (Corning No. 0211) was used for the substrate. In order to obtain a large relative magnetic permeability, Ni is used as a magnetic material.
When using Fe, film formation was performed in a magnetic field by applying a magnetic field of about 100 Oe. When using a CoZr-based amorphous alloy, heat treatment was performed in a rotating magnetic field after film formation in a magnetic field.

In order to produce a cylindrical noise filter, a method was employed in which the structure produced on the substrate as described above was peeled off from the substrate, and a sheet-like structure was rounded into a cylindrical shape.

[0015] As other manufacturing methods, in addition to the above-mentioned IBS method, RF sputtering, magnetron sputtering, vapor deposition, plating, roll method, coating method, screen printing method, rolling method and the like may be used. The effect of can be obtained.

As a method for forming a cylindrical shape, besides using the sheet peeled off from the substrate as described above, for example, a film-shaped magnetic material is directly formed on a flexible non-magnetic insulator sheet such as polyimide. And then rounding it into a cylindrical shape.

FIG. 3 is a cross-sectional view of FIGS. 2 (a) and 2 (b).
It is a diagram illustrating a relationship between the relative magnetic permeability and the thickness t _m of the magnetic body 1. NiFe and CoZrNb are used as the magnetic material 1, and SiO ₂ (0.1 μm thick) is used as the non-magnetic insulator 2.
It was used.

[0018] In FIG. 3, the relative permeability μ _r ', μ _r "is static relative permeability mu _r' are normalized by (0), also, t _m is standardized by the skin depth δ It is. electrical resistivity [rho _m of the skin depth [delta] is the magnetic body, μ _r '(0), the frequency f, using the magnetic permeability mu ₀ of a _{vacuum, δ = [2ρ m / (} 2πfμ r' (0) μ ₀ )] ^1/2 (2) In the case of NiFe, μ _r ′ (0) = 2500, ρ
_m = 20 μΩcm, and in CoZrNb, μ _r ′ (0) =
5000, ρ _m = 120 μΩcm. As shown in FIG. 3, μ _r ″ becomes larger due to eddy current loss when t _m / δ is in the range of 0.1 to 10. From this, a large μ _r ″ is obtained.
It can be seen that it is effective to set t _m to a thickness that is 1/10 to 10 times δ in order to realize

In FIGS. 2A and 2B, the magnetic material 1
Μ _r ′ (0) = 5000, ρ _m = 120 μΩcm, t _m
FIG. 4 shows frequency characteristics of relative magnetic permeability when CoZrNb = 2 μm is used and SiO ₂ (0.1 μm thick) is used as the nonmagnetic insulator 2. [delta] is a 0.4~1.4μm in 30～1000MHz, the _{t m δ / 10 ≦ t m} ≦ 10
satisfies δ. μ _r '(0) = 5000, f _c = 15M
From Hz, the product _{μ r '(0) × f} c is 75GHz, and the
It is 10 times or more as compared with the equation (1). As a result, 30-1
In _{000MHz | μ r |, μ r} " is a value greater than the value in the ferrite magnetic material of Figure 12.

Next, in FIG. 2 (a) and (b), as the magnetic substance _{1 μ r '(0) =} 5000, ρ m = 120μΩc
FIG. 5 shows the frequency characteristics of the impedance of a noise filter formed as shown in FIG. 1 using CoZrNb of m and t _m = 2 μm and SiO ₂ (0.1 μm thick) as the nonmagnetic insulator 2. The size of the noise filter is d = 3 mm, t
= 60 μm, l = 10 mm. In this embodiment, 30
Impedance of ~ 1000MHz is several tens to 300Ω
14 and equivalent to the conventional parts shown in FIG. 14, and the part volume could be reduced to about 1/10 ² .

(Embodiment 2) FIG. 6 shows an embodiment of a magnetic particle-dispersed noise absorber according to the present invention, in which one or a plurality of magnetic bodies 1 are granular, and the granular magnetic bodies 1 are non-magnetic insulators. 2 are dispersed. The size of the magnetic body 1 is 1/10 to 10 times the skin depth, and the magnetic bodies are arranged at a distance of 50 nm or more by the non-magnetic insulator 2.

The magnetic particle-dispersed noise absorber was manufactured by an ion beam sputtering (IBS) method. The sputtering conditions were as follows: operating vacuum degree: 1 × 10 ⁻⁴ Torr (using Ar as a sputtering gas), acceleration voltage: 1 kV, substrate temperature: 160
° C. As a target, a CoZr-based amorphous alloy (for example, CoZrNb [film composition: 87, 5, 8 at
%]) And a composite target of SiO ₂ or Ni
Fe alloy (film composition: 82.5, 17.5 at%) and Si
Using a composite target with O ₂ , glass (Co
ring No. 0211) was used. In order to obtain a large relative magnetic permeability, when NiFe is used as a magnetic material, film formation is performed in a magnetic field by applying a magnetic field of about 100 Oe. After the medium film formation, heat treatment was performed in a rotating magnetic field. In order to produce a cylindrical noise filter, a method in which the noise absorber produced on the substrate as described above was peeled off from the substrate and formed into a sheet was rounded into a cylindrical shape.

Other manufacturing methods include, in addition to the above-mentioned IBS method, RF sputtering, magnetron sputtering, vapor deposition, roll coating, coating, screen printing, and mixing magnetic particles in a nonmagnetic insulator paste. A similar effect can be obtained by using a method or the like. In addition, as a method of forming a cylindrical shape, in addition to using a sheet peeled from the substrate as described above, a method of using a material deposited on a cylindrical substrate, a method of hollowing out a bulk shape into a cylindrical shape, a method of forming a paste shape There is a method of molding a product into a cylindrical shape from the beginning.

FIG. 7 is a diagram showing the relationship between the relative permeability and the particle size d _m of the magnetic body 1 of Fig. NiF as the magnetic material 1
e, CoZrNb, and SiO 2 as the non-magnetic insulator ₂ were used, and the distance between the magnetic bodies was 0.1 μm.

[0025] In FIG 7, the relative permeability μ _r ', μ _r "is static relative permeability mu _r' are normalized by (0), also, d _m is standardized by the skin depth δ For NiFe, μ _r '(0) =
2500, ρ _m = 20 μΩcm, μ _r ′ for CoZrNb
(0) = 5000 and ρ _m = 120 μΩcm. As shown in the figure, μ _r ″ becomes larger due to eddy current loss when d _m / δ is in the range of 0.1 to 10. Therefore, to realize a large μ _r ″, d _m is smaller than δ. It can be seen that setting the thickness to 1/10 to 10 times is effective.

Next, _μr ′ (0) = 250 as the magnetic material 1
0, ρ _m = 20 μΩcm NiFe
As used SiO _2, and the frequency characteristics were measured relative permeability distance d _n between the magnetic variety varied. FIG. 8 shows the results.
Here, the particle diameter d _m of NiFe was set to 50nm. The skin depth of NiFe in this frequency band is 0.16 to
1.6 μm, and the NiFe particle size of 50 nm is sufficiently smaller than this. Therefore, if SiO ₂ maintains electrical insulation between NiFe, the magnetic resonance frequency of NiFe is 650M.
Up to Hz, μ _r ′ is constant and μ _r ″ is low.
When d _n is as small as 5 nm, μ _r ′ starts from around 30 MHz.
, And a rapid increase in μ _r ”, resulting in incomplete electrical insulation. On the other hand, 650 at d _n = 50 nm.
Μ _r ′ is constant up to MHz, the electrical insulation is almost maintained, and when d _n = 100 nm, the insulating effect is further ensured. From the above, it can be seen that it is effective to set the distance between the magnetic bodies to 50 nm or more in order to maintain the electrical insulation between the magnetic bodies.

In FIG. 6, μ _r '(0) =
5000, ρ _m = 120 μΩcm, d _m = 2 μm CoZ
FIG. 9 shows the frequency characteristics of the relative magnetic permeability when rNb is used and SiO ₂ is used as the nonmagnetic insulator. Where d _n
= 0.1 μm. δ is 0.3 at 30 to 1000 MHz.
A 4~1.4μm, d _m meets _{δ / 10 ≦ d m ≦ 10δ} . Further, μ _r ′ (0) = 5000, f _c = 15
From MHz, the product _{μ r '(0) × f} c is a 75 GHz (1)
It is 10 times or more as compared with the formula. As a result, 30 to 1000
In MHz, | μ _r |, μ _r "are larger than the values in the ferrite-based magnetic material of FIG.

FIG. 10 shows an embodiment of a noise filter using the noise absorber of FIG. FIG. 10 shows a structure in which the noise absorber of FIG.

FIG. 11 shows the frequency characteristic of the impedance in the noise filter of FIG. Here, the magnetic material 1
Μ _r ′ (0) = 5000, ρ _m = 120 μΩcm, d _m
= 2 μm of CoZrNb as a non-magnetic insulator
₂ , and d _n = 0.1 μm. δ is 30 to 1000
A 0.4~1.4μm in MHz, d _m is [delta] / 10 ≦
It satisfies d _m ≦ 10δ. The size of the noise filter is d = 3 mm, t = 60 μm, and 1 = 10 mm. 3
The impedance of 0 to 1000 MHz is several tens to 300
14 is equivalent to that of the conventional part shown in FIG. 14, and at this time, the part volume can be reduced to about 1/10 ² .

The magnetic material 1 is made of Fe, Ni, C
o-based alloy-based magnetic material, while the non-magnetic insulator 2 is made of SiO ₂ , AlN, Al ₂ O ₃ , BN, Ti
Even if N, SiC, polyimide, rubber or the like is used, the same effect as described above can be obtained.

As described above, according to the present invention, it is possible to reduce the component size as compared with the conventional noise filter.

[0032]

As described above, according to the present invention,
A high-performance noise absorber utilizing eddy current loss is obtained,
Further, it is possible to provide a small noise filter.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of a noise filter according to the present invention.

FIG. 2 is a schematic diagram showing details of a noise filter of the present invention.

FIG. 3 is a graph showing the magnetic layer thickness dependency of the relative magnetic permeability.

FIG. 4 is a graph showing frequency characteristics of relative magnetic permeability.

FIG. 5 is a graph showing frequency characteristics of impedance.

FIG. 6 is a conceptual diagram showing an embodiment of a noise absorber according to the present invention.

FIG. 7 is a graph showing the dependence of the relative magnetic permeability on the particle diameter of a magnetic substance.

FIG. 8 is a graph showing frequency characteristics of relative magnetic permeability when the distance between magnetic bodies is changed.

FIG. 9 is a graph showing frequency characteristics of relative magnetic permeability.

FIG. 10 is a schematic diagram showing another embodiment of the noise filter of the present invention.

FIG. 11 is a graph showing frequency characteristics of impedance.

FIG. 12 is a graph showing frequency characteristics of relative permeability of a conventional material (ferrite-based magnetic material).

FIG. 13 is a schematic diagram showing an example of a conventional noise filter.

FIG. 14 is a graph showing frequency characteristics of impedance of a conventional material (ferrite-based magnetic material).

[Explanation of symbols]

 1 magnetic body, 2 non-magnetic insulator.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-281108 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01F 1/12-1/375

Claims (2)

(57) [Claims] The non-magnetic insulator has a skin depth of 0.1 to 0.1.
At least one granular magnetic material having a particle size of 10 times, 50n
A noise absorber characterized by being dispersed at intervals of m or more. 2. The method according to claim 1, wherein the non-magnetic insulator has a skin depth of 0.1 to
At least one granular magnetic material having a particle size of 10 times, 50n
A noise filter characterized in that a noise absorber dispersed at intervals of m or more is wound into a single cylinder or more.