JP4788593B2 - Common mode noise filter - Google Patents

Description

  The present invention relates to a common mode noise filter used in various electronic devices such as digital devices, AV devices, and information communication terminals.

  As shown in FIG. 4, the conventional common mode noise filter of this type includes a first magnetic layer 1 and a second magnetic layer 1, and a first magnetic layer 1 and a second magnetic layer 2. The first to fifth nonmagnetic layers 3a to 3e provided therebetween, and the first to fifth nonmagnetic layers 3a to 3e include first and second coils 4, 5 respectively. Was forming. The first coil 4 includes a first extraction electrode 6 and a spiral first coil conductor 7, and the second coil 5 includes a spiral second coil conductor 8 and a second extraction coil. And the first lead electrode 6 on the upper surface of the first nonmagnetic material layer 3a, the first coil conductor 7 on the upper surface of the second nonmagnetic material layer 3b, The coil conductor 8 was provided on the upper surface of the third nonmagnetic material layer 3c, and the second extraction electrode 9 was provided on the upper surface of the fourth nonmagnetic material layer 3d.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2001-60514 A

  In the above-described conventional common mode noise filter, in order to reduce the stray capacitance between the first coil 4 and the second coil 5, it is between the first coil conductor 7 and the second coil conductor 8. In order to prevent cracking and deformation due to simultaneous firing of a magnetic layer and a glass ceramic layer having different thermal shrinkage rates, a glass ceramic layer is formed on (the third nonmagnetic layer 3c portion). When a glass ceramic layer is formed between the magnetic layers 1 and between the second magnetic layers 2, the permeability of the magnetic layer is reduced by diffusion of the glass ceramic component into the magnetic layer. Therefore, there is a problem that the impedance of the common mode component cannot be increased.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a common mode noise filter capable of increasing the impedance of a common mode component.

  In order to achieve the above object, the present invention has the following configuration.

  The invention according to claim 1 of the present invention includes a plurality of insulating layers and first to fourth conductors provided on the plurality of insulating layers, and includes the first conductor and the second conductor. And connecting the third conductor and the fourth conductor, making the second conductor and the third conductor spiral, and facing each other, and the first to fourth conductors And at least two magnetic layers above and below, and two nonmagnetic layers provided between the two magnetic layers, and further, a low dielectric constant layer containing glass is formed between the nonmagnetic layers, The insulating layer located between the second conductor and the third conductor is made of a material having low permeability containing glass, and both the magnetic layer and the nonmagnetic layer are made of ferrite. According to configuration, low dielectric constant containing glass between nonmagnetic layers Therefore, the magnetic layer is not directly in contact with the low dielectric constant layer at the interface, thereby reliably preventing the glass component of the low dielectric constant layer from diffusing into the magnetic layer. Since the stress applied to the magnetic layer from the low dielectric constant layer, which has a different thermal shrinkage depending on the magnetic layer, can be reduced, the magnetic layer shrinkage during firing is not hindered. Therefore, the magnetic permeability of the magnetic layer does not decrease, and as a result, the impedance of the common mode component can be increased. Furthermore, since the magnetic layer and the nonmagnetic layer that is in contact with the magnetic layer are both made of ferrite and are not dissimilar materials, cracking or stress may occur between the magnetic layer and the nonmagnetic layer. The effect that there is no need to do is obtained.

  In the invention according to claim 2 of the present invention, in particular, the thermal contraction rate of the nonmagnetic layer is a value between the thermal contraction rate of the magnetic layer and the thermal contraction rate of the low dielectric constant layer. According to the present invention, it is possible to effectively relieve the shrinkage difference between the thermal shrinkage rate of the magnetic layer and the thermal shrinkage rate of the low dielectric constant layer, thereby reducing the stress applied to the magnetic layer from the low dielectric constant layer. Since the magnetic layer shrinkage at the time is not hindered, the magnetic layer will be densely fired, and this will not reduce the magnetic permeability of the magnetic layer. The effect that it can be performed is obtained.

  The invention according to claim 3 of the present invention particularly includes an insulating layer positioned between the second conductor and the lower magnetic layer, and an insulating layer positioned between the third conductor and the upper magnetic layer. According to this configuration, the low dielectric constant layer exists only in the nonmagnetic layer, and the magnetic layer is not in direct contact with the low dielectric constant layer. In particular, it is possible to relieve the stress due to the difference in shrinkage during firing between the magnetic layer and the low dielectric constant layer, thereby obtaining the effect of increasing the impedance of the common mode component.

  As described above, the common mode noise filter of the present invention includes at least two magnetic layers above and below the first to fourth conductors, and two nonmagnetic layers provided between the two magnetic layers, In addition, a low dielectric constant layer containing glass is formed between the nonmagnetic layers, and an insulating layer located between the second conductor and the third conductor is made of a material containing glass and having a low magnetic permeability. Therefore, there is a nonmagnetic layer between the low dielectric constant layer containing this glass and the magnetic layer, so that the magnetic layer does not directly contact the low dielectric constant layer at the interface. As a result, the magnetic layer does not decrease in permeability, and as a result, the impedance of the common mode component can be increased.

  Hereinafter, a common mode noise filter according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of a common mode noise filter according to an embodiment of the present invention, and FIG. 2 is a perspective view of the common mode noise filter.

  As shown in FIGS. 1 and 2, the common mode noise filter according to the embodiment of the present invention includes first to fourth insulating layers 11 a to 11 d and the first to fourth insulating layers 11 a to 11 d. The first to fourth conductors 12 to 15 are provided, and the first conductor 12 and the second conductor 13 are connected, and the third conductor 14 and the fourth conductor 15 are connected. Further, the second conductor 13 and the third conductor 14 are spirally shaped and opposed to each other. Further, above and below the first to fourth conductors 12 to 15, respectively, at least two magnetic layers 16 and two nonmagnetic layers 17 provided between the two magnetic layers 16 are provided, and A low dielectric constant layer 18 containing glass is formed between the nonmagnetic layers 17, and a third insulating layer 11c located between the second conductor 13 and the third conductor 14 contains glass. The magnetic layer 16 and the nonmagnetic layer 17 are both made of ferrite and made of a material having low magnetic permeability.

  The said structure WHEREIN: The said 1st-4th insulating layers 11a-11d consist of an insulating material, the 1st conductor 12 is on the upper surface of the 1st insulating layer 11a, and the upper surface of the 2nd insulating layer 11b. The second conductor 13 is formed on the upper surface of the third insulating layer 11c, and the fourth conductor 15 is formed on the upper surface of the fourth insulating layer 11d. The first insulating layer 11a is made of a magnetic material such as Ni-Zn ferrite, and the second to fourth insulating layers 11b to 11d contain glass such as glass ceramic, and the first The insulating layer 11a and the magnetic layer 16 are made of a material having a lower magnetic permeability.

  The first to fourth conductors 12 to 15 are formed by plating a conductive material such as silver, and the first conductor 12 and the second conductor 13 are vias formed on the second insulating layer 11b. They are connected via electrodes (not shown) to form one coil. Further, the third conductor 14 and the fourth conductor 15 are connected via a via electrode 19 formed in the fourth insulating layer 11d to constitute one other coil.

  The shapes of the second conductor 13 and the third conductor 14 are formed in a spiral shape, and are substantially overlapped when viewed from above. Further, a fifth insulating layer 11e made of a magnetic material is provided on the upper surface of the fourth conductor 15. Further, the third insulating layer 11c formed between the second conductor 13 and the third conductor 14 is made of a material having a low magnetic permeability containing glass such as glass ceramic. At least two magnetic layers 16 are formed below the first insulating layer 11a and above the fifth insulating layer 11e, respectively. The magnetic layer 16 is made of a magnetic material having an insulating property and made of Ni—Zn ferrite. Between the two magnetic layers 16, two nonmagnetic layers 17 made of a nonmagnetic material made of Cu-Zn ferrite are provided. Furthermore, between the two nonmagnetic layers 17, there is provided a low dielectric constant layer 18 made of a material having a low permeability and containing an insulating material such as glass ceramic.

  That is, the low dielectric constant layer 18 is sandwiched between the two nonmagnetic layers 17 below the first insulating layer 11a and the fifth insulating layer 11e, respectively, and these are sandwiched between the two magnetic layers 16. Thus, since the nonmagnetic layer 17 exists between the magnetic layer 16 and the low dielectric constant layer 18, the magnetic layer 16 and the low dielectric constant layer 18 are not in direct contact with each other. The dielectric constant of the low dielectric constant layer 18 is lower than that of the magnetic layer 16 and the nonmagnetic layer 17.

  Further, the heat shrinkage rate of the nonmagnetic layer 17 is a value between the heat shrinkage rate of the magnetic layer 16 and the heat shrinkage rate of the low dielectric constant layer 18. Since the difference in contraction of the thermal contraction rate of the dielectric constant layer 18 can be effectively reduced, the stress applied to the magnetic layer 16 from the low dielectric constant layer 18 can be reduced, thereby reducing the contraction of the magnetic layer 16 during firing. It will not be inhibited. As a result, since the magnetic layer 16 is densely fired, the magnetic permeability of the magnetic layer 16 does not decrease, and thereby the impedance of the common mode component can be increased.

  And the main-body part 21 of a common mode noise filter as shown in FIG. 2 is formed by the above-mentioned structure. Further, first to fourth external electrodes 22 to 25 are provided on both sides of the main body portion 21, and the first to fourth external electrodes 22 to 25 are provided to the first to fourth electrodes. It is formed by printing silver so as to be connected to each one end of each of the conductors 12 to 15. Moreover, a nickel plating layer and a tin plating layer are applied to the surfaces of the first to fourth external electrodes 22 to 25, respectively.

  The first to fourth conductors 12 to 15 are not formed by plating, but may be formed by other methods such as printing and vapor deposition.

  Next, the manufacturing method of the common mode noise filter in one embodiment of the present invention will be described.

  In FIG. 1 and FIG. 2, first, rectangular first to fourth insulating layers 11 a to 11 d, a magnetic layer 16, a mixture of magnetic material and glass, which are raw materials, and a powder and resin of a nonmagnetic material. A predetermined number of nonmagnetic layers 17 and low dielectric constant layers 18 are formed. At this time, the via electrode 19 is formed by punching holes in predetermined portions of the second insulating layer 11b and the fourth insulating layer 11d by laser, punching, or the like, and filling the holes with silver.

  Next, the magnetic layer 16, the nonmagnetic layer 17, the low dielectric constant layer 18, the nonmagnetic layer 17, and the magnetic layer 16 are laminated in this order.

  Next, after laminating the first insulating layer 11a made of a magnetic material, the first conductor 12 is formed on the upper surface by plating.

  Next, a second insulating layer 11b having a via electrode (not shown) and containing glass is laminated on the upper surface of the first conductor 12. At this time, the first conductor 12 and the via electrode (not shown) are connected.

  Next, the second conductor 13 is formed in a spiral shape on the upper surface of the second insulating layer 11b by plating. At this time, the second conductor 13 and the via electrode (not shown) are connected. Thereafter, a third insulating layer 11 c containing glass is laminated on the upper surface of the second conductor 13.

  Next, the third conductor 14 is formed in a spiral shape on the upper surface of the third insulating layer 11c by plating.

  Next, a fourth insulating layer 11 d having a via electrode 19 and containing glass is laminated on the upper surface of the third conductor 14. At this time, the third conductor 14 and the via electrode 19 are connected.

  Next, the fourth conductor 15 is formed on the upper surface of the fourth insulating layer 11d by plating. At this time, the fourth conductor 15 and the via electrode 19 are connected.

  In addition, the formation method of the said 1st-4th conductors 12-15 forms the conductor of a predetermined pattern shape by plating on the base plate (not shown) prepared separately, and this conductor is made into each insulator layer after that. It is formed by transferring.

  Next, after the fifth insulating layer 11e is laminated on the upper surface of the fourth conductor 15, the magnetic layer 16, the nonmagnetic layer 17, the low dielectric constant layer 18, the nonmagnetic layer 17, and the magnetic layer 16 are arranged in this order. The main body 21 of the common mode noise filter is formed by laminating.

  Next, the main body portion 21 is fired at a predetermined temperature and time, and further, silver is connected to both end surfaces of the main body portion 21 with the respective one end portions of the first to fourth conductors 12 to 15. Is printed, and the first to fourth external electrodes 22 to 25 are formed.

  Finally, a nickel plating layer and a tin plating layer are formed on the surfaces of the first to fourth external electrodes 22 to 25 by plating.

  As described above, in the embodiment of the present invention, since the nonmagnetic layer 17 exists between the glass-containing low dielectric constant layer 18 and the magnetic layer 16, the magnetic layer 16 is directly reduced in thickness. There is no contact with the dielectric constant layer 18 at the interface, and thereby the magnetic permeability of the magnetic layer 16 does not decrease, so that the effect of increasing the impedance of the common mode component can be obtained.

  That is, it is possible to prevent the glass component of the low dielectric constant layer 18 from diffusing into the magnetic layer 16 and to reduce the stress applied to the magnetic layer 16 from the low dielectric constant layer 18 having a different thermal shrinkage rate by the nonmagnetic layer 17. Therefore, the shrinkage of the magnetic layer 16 at the time of firing is not hindered, whereby the magnetic layer 16 can be densely fired, and the magnetic permeability of the magnetic layer 16 can be prevented from being lowered. . The magnetic layer 16 and the nonmagnetic layer 17 with which the magnetic layer 16 is in contact are both made of ferrite and are not different materials, and therefore cracks between the magnetic layer 16 and the nonmagnetic layer 17. And no stress is generated.

  As shown in FIG. 3, the first and second insulating layers 11a and 11b located between the second conductor 13 and the lower magnetic layer 16, the third conductor 14, and the upper magnetic layer 16 are provided. If the fourth and fifth insulating layers 11d and 11e positioned between the two are made nonmagnetic layers made of a nonmagnetic material, the low dielectric constant layer 18 exists only between the nonmagnetic layers 17, Further, since the magnetic layer 16 is not in direct contact with the low dielectric constant layer 18, it is possible to alleviate stress due to a shrinkage difference during firing of the magnetic layer 16 and the low dielectric constant layer 18 as a whole. It is possible to prevent the magnetic permeability of the magnetic layer 16 from decreasing and to increase the impedance of the common mode component.

  In the common mode noise filter according to the embodiment of the present invention, a pair of coils is described. However, two or more pairs of coils may be formed to form an array type.

  The common mode noise filter according to the present invention has an effect that the impedance of the common mode component can be increased, and is particularly used as a noise countermeasure for various electronic devices such as digital devices, AV devices, and information communication terminals. This is useful in common mode noise filters.

The disassembled perspective view of the common mode noise filter in one embodiment of this invention Perspective view of the common mode noise filter An exploded perspective view showing another example of the common mode noise filter Exploded perspective view of a conventional common mode noise filter

Explanation of symbols

11a-11e 1st-5th insulating layer 12-15 1st-4th conductor 16 Magnetic layer 17 Nonmagnetic layer 18 Low dielectric constant layer

Claims (3)

A plurality of insulating layers; and first to fourth conductors provided in the plurality of insulating layers, connecting the first conductor and the second conductor, and the third conductor and the fourth conductor. The second conductor and the third conductor are spirally shaped and opposed to each other, and at least two magnets are located above and below the first to fourth conductors, respectively. A layer and two nonmagnetic layers provided between the two magnetic layers, a low dielectric constant layer containing glass between the nonmagnetic layers, and the second conductor and the third conductor; A common mode noise filter in which an insulating layer positioned between the layers is made of a material having low permeability containing glass, and both the magnetic layer and the nonmagnetic layer are made of ferrite. The common mode noise filter according to claim 1, wherein the heat shrinkage rate of the nonmagnetic layer is a value between the heat shrinkage rate of the magnetic layer and the heat shrinkage rate of the low dielectric constant layer. 2. The common mode according to claim 1, wherein the insulating layer positioned between the second conductor and the lower magnetic layer and the insulating layer positioned between the third conductor and the upper magnetic layer are nonmagnetic layers. Noise filter.

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