JP2016213332A - Common mode noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common node noise filter capable of suppressing failure of external electrode formation and occurrence of mount defect.SOLUTION: First and second coil conductors 14 and 15 constituting a first coil 12 and third and fourth coil conductors 16 and 17 constituting a second coil 13 are alternately arranged, the first coil conductor 14 and the third coil conductor 16 are magnetically coupled to each other to form a first common mode filter portion 18, and the second coil conductor 15 and the fourth coil conductor 17 are magnetically coupled to each other to form a second common mode filter portion 19. The first common mode filter portion 18 and the second common mode filter portion 19 are connected in series, and a constraining layer or a metal layer 24 having a shrinkage factor smaller than that of an insulator layer is formed at least around the second and fourth coil conductors 15 and 17 or at the outside portion in the lamination direction of the second and fourth coil conductors 15 and 17.SELECTED DRAWING: Figure 4

Description

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

  A conventional common mode noise filter of this type has a first coil 2 and a second coil 3 formed on a plurality of laminated insulator layers 1a to 1j as shown in FIG. One coil 2 is configured by connecting spiral first and second coil conductors 4a and 4b, and the second coil 3 is configured by connecting spiral third and fourth coil conductors 5a and 5b. The first and second coil conductors 4a and 4b constituting the first coil 2 and the third and fourth coil conductors 5a and 5b constituting the second coil 3 are alternately laminated. It had been. Further, the first coil conductor 4a and the third coil conductor 5a are magnetically coupled to form the first common mode filter unit 6, and the second coil conductor 4b and the fourth coil conductor 5b are magnetically coupled. A second common mode filter unit 7 is formed by coupling, and the first common mode filter unit 6 and the second common mode filter unit 7 are connected in series to ensure a high common mode impedance and to reduce common mode noise. Had to be removed.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

JP 2002-373810 A

  In the above-described common mode noise filter, the second common mode filter is used based on the number of turns of the first common mode filter unit 6 as shown in FIGS. When the number of turns of the portion 7 is reduced, the insulating layer is increased around the second common mode filter portion 7 as compared with the first common mode filter portion 6, so that the second common mode is set during firing. The periphery of the filter unit 7 contracts more than the periphery of the first common mode filter unit 6, thereby deforming the outer shape of the laminate, and as a result, external electrode formation defects and mounting defects are likely to occur. was there.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a common mode noise filter capable of suppressing the occurrence of external electrode formation defects and mounting defects.

  In order to achieve the above-described object, the present invention provides the number of turns of the second and fourth coil conductors in the second common mode filter unit as compared with the number of turns of the first and third coil conductors in the first common mode filter unit. A constraining layer or a metal layer having a shrinkage ratio smaller than that of the insulator layer is provided at least around the second and fourth coil conductors or on the outer portion in the stacking direction of the second and fourth coil conductors. The configuration is provided.

  The common mode noise filter of the present invention can prevent the insulating layer around the second common mode filter portion from contracting by the constraining layer or the metal layer, so that the outer shape of the laminate is deformed. As a result, it is possible to suppress the occurrence of external electrode formation defects and mounting defects.

1 is an exploded perspective view of a common mode noise filter according to Embodiment 1 of the present invention. Perspective view of the common mode noise filter Cross section of the common mode noise filter Sectional drawing of the common mode noise filter in Embodiment 2 of this invention Sectional view of another example of the common mode noise filter Sectional view of another example of the common mode noise filter Sectional view of another example of the common mode noise filter Sectional view of another example of the common mode noise filter Exploded perspective view of a conventional common mode noise filter Cross section of the common mode noise filter

(Embodiment 1)
1 is an exploded perspective view of a common mode noise filter according to Embodiment 1 of the present invention, FIG. 2 is a perspective view of the common mode noise filter, and FIG. 3 is a sectional view of the common mode noise filter. Note that. FIG. 3 is not exactly a cross-sectional view of FIG. 1, but is schematically illustrated for the sake of simplicity, and the same applies to FIGS.

  As shown in FIGS. 1 to 3, the common mode noise filter according to Embodiment 1 of the present invention includes first to seventh insulator layers 11 a to 11 g stacked in the vertical direction, and the first to seventh layers. The first coil 12 and the second coil 13 are formed on the insulating layers 11a to 11g, and the first coil 12 is formed by a spiral first coil conductor 14 and a second coil conductor 15. The second coil 13 is composed of a spiral third coil conductor 16 and a fourth coil conductor 17, and the first and second coil conductors 14 constituting the first coil 12 are configured. 15 and third and fourth coil conductors 16 and 17 constituting the second coil 13 are alternately arranged in the stacking direction.

  Further, the first coil conductor 14 and the third coil conductor 16 are magnetically coupled to form a first common mode filter unit 18, and the second coil conductor 15 and the fourth coil conductor 17 are magnetically coupled. Thus, a second common mode filter unit 19 is formed, and the first common mode filter unit 18 and the second common mode filter unit 19 are connected in series.

  Then, the winding direction of the coil conductors 14 and 16 in the first common mode filter unit 18 and the winding direction of the coil conductors 15 and 17 in the second common mode filter unit 19 are opposite to generate a magnetic flux. The directions are opposite to each other. In addition, the number of turns of the second and fourth coil conductors 15 and 17 in the second common mode filter unit 19 is equal to the number of turns of the first and third coil conductors 14 and 16 in the first common mode filter unit 18. It is less than the number.

  Furthermore, the other insulator layer 11a, on the outer side portion of the second common mode filter portion 19 in the stacking direction of the second and fourth coil conductors 15, 17, that is, below the second common mode filter portion 19, A constraining layer 21 having a shrinkage rate smaller than 11c to 11g is disposed.

  In the above configuration, the first to seventh insulator layers 11a to 11g are stacked in order from the bottom, and the second to sixth insulator layers 11b to 11f are not magnetic materials, for example, Cu-Zn ferrite. The sheet is made of an insulating nonmagnetic material such as glass ceramic. The first and seventh insulator layers 11a and 11g are formed in a sheet shape from an insulating magnetic material such as Cu-Ni-Zn ferrite. The number of sheets constituting the first to seventh insulator layers 11a to 11g is not limited to the number shown in FIG.

  The second insulator layer 11b is a constraining layer 21 having a shrinkage rate smaller than those of the other insulator layers 11a and 11c to 11g. As a method of reducing the shrinkage rate, the second insulator layer 11b (constraint layer 21) is reduced in the amount of organic solvent and plasticizer, the amount of filler is increased, and the particle size of ferrite and glass is decreased. There are methods.

  Further, first and second coils 12 and 13 are formed inside the second to sixth insulator layers 11b to 11f, and the first coil 12 is connected to the spiral first coil conductor 14 and The second coil conductor 15 is constituted by a spiral second coil conductor 15, and the second coil 13 is constituted by a third spiral coil conductor 16 and a fourth spiral coil conductor 17.

  The first to fourth coil conductors 14 to 17 are each formed by plating or printing a conductive material such as silver in a spiral shape.

  At this time, the first coil conductor 14 is the upper surface of the fifth insulator layer 11e, the second coil conductor 15 is the upper surface of the third insulator layer 11c, and the third coil conductor 16 is the fourth insulator layer. The upper surface of 11d and the fourth coil conductor 17 are respectively formed on the upper surface of the second insulator layer 11b.

  That is, the first and second coil conductors 14 and 15 constituting the first coil 12 and the third and fourth coil conductors 16 and 17 constituting the second coil 13 are laminated alternately. Has been. Moreover, since the 1st-4th coil conductors 14-17 are laminated | stacked on the up-down direction, space saving is also realizable.

  Here, the first coil conductor 14 and a part of the third coil conductor 16 are arranged at substantially the same position when viewed from above, and the winding direction is also made to be the same direction so that the first common mode filter is magnetically coupled. Similarly, a part 18 of the second coil conductor 15 and a part of the fourth coil conductor 17 are arranged at substantially the same position in a top view, and the winding direction is also set to be the same direction so as to be magnetically coupled. A second common mode filter unit 19 is formed.

  Further, the number of turns (number of turns) of the second and fourth coil conductors 15 and 17 in the second common mode filter unit 19 is equal to the first and third coil conductors 14 in the first common mode filter unit 18. , Less than 16 windings (turns). At this time, the first to fourth coil conductors 14 to 17 have substantially the same inter-conductor pitch, and the second and fourth coil conductors 15 and 17 are the upper surfaces of the first and third coil conductors 14 and 16, respectively. Opposite visually. Furthermore, the innermost portions of the second and fourth coil conductors 15 and 17 are opposed to the innermost portions of the first and third coil conductors 14 and 16.

  Further, the first coil conductor 14 and the second coil conductor 15 are connected to each other via the first via electrode 20a formed in the fourth and fifth insulator layers 11d and 11e, respectively. The coil 12 is configured. Further, the third coil conductor 16 and the fourth coil conductor 17 are connected to each other via the second via electrode 20b formed in the third and fourth insulator layers 11c and 11d, respectively. The coil 13 is configured.

  The first via electrode 20a is provided at the same position when viewed from above, and the second via electrode 20b is also provided at the same position when viewed from above. In addition, the first via electrode 20a and the second via electrode 20b are formed by drilling holes in predetermined portions of each insulator layer with a laser and filling the holes with silver.

  And the laminated body 22 of a common mode noise filter is formed as shown in FIG. Further, first to fourth external electrodes 23a to 23d are provided on both end faces of the laminate 22, and the first to fourth external electrodes 23a to 23d are respectively first to fourth coil conductors. 14 to 17 are connected. Further, the first to fourth external electrodes 23a to 23d are formed by printing silver on the end face of the main body portion 22, and a nickel plating layer is formed on these surfaces by plating. A low melting point metal plating layer such as tin or solder is formed on the surface by plating.

  As described above, in the common mode noise filter according to the first exemplary embodiment of the present invention, the second and fourth coil conductors 15 and 17 constituting the second common mode filter unit 19 have other portions in the stacking direction. Since the constraining layer 21 (second insulator layer 11b) having a shrinkage rate smaller than that of the insulating layers 11a and 11c to 11g is provided, the constraining layer 21 insulates the surroundings of the second common mode filter unit 19. Since the body layer can be prevented from shrinking, the outer shape of the laminate 22 can be prevented from being deformed, and as a result, the occurrence of external electrode formation defects and mounting defects can be suppressed. An effect is obtained.

  That is, even if the insulating layer located around the second common mode filter portion 19 is to contract, the constraining layer 21 is not easily contracted, so that the contraction of the insulating layer is reduced by being pulled by the constraining layer 21.

  In addition, the first common mode filter unit 18 and the second common mode filter unit 19 are configured such that the direction of magnetic flux generation is reversed, and the first and third coil conductors 14 in the first common mode filter unit 18 are provided. , 16 and the number of turns of the second and fourth coil conductors 15 and 17 in the second common mode filter unit 19 are different from each other. Different frequency characteristics are generated in the common mode filter unit 19, whereby a common mode noise attenuation amount can be obtained in two frequency bands.

  In the first embodiment described above, the second insulating layer 11b is the constraining layer 21, but any one of the first, third, and fourth insulating layers 11a, 11c, and 11d is the constraining layer 21. Alternatively, a plurality of the first to fourth insulator layers 11a to 11d may be used as the constraining layer 21.

  Further, in at least one of the first to fourth insulator layers 11a to 11d, a portion surrounding the periphery of the second and fourth coil conductors 15 and 17 in a top view may be used as the constraining layer 21. At this time, the insulator layer on which the constraining layer 21 is formed is formed by the constraining layer 21 and a portion that is not the constraining layer 21.

(Embodiment 2)
FIG. 4 is a cross-sectional view of a common mode noise filter according to Embodiment 2 of the present invention. In the second embodiment of the present invention, components having the same configurations as those of the first embodiment of the present invention are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment of the present invention and the first embodiment of the present invention is that the metal layer 24 plays the same role as the constraining layer 21 around the second and fourth coil conductors 15 and 17. This is the point.

  The metal layer 24 is formed on the same insulator layer as the insulator layer on which the second and fourth coil conductors 15 and 17 are formed by plating or printing a metal such as silver or an alloy.

  At this time, the metal layer 24 has a spiral shape, and the outermost part thereof is substantially the same as the outermost part of the first and third coil conductors as viewed from above, or is exposed from the first and third coil conductors. It has become. If the metal layer 24 is exposed from the first and third coil conductors 14 and 16, the effect of preventing the insulating layer around the second common mode filter unit 19 from being contracted by the metal layer 24 is enhanced.

  As described above, in the common mode noise filter according to the second exemplary embodiment of the present invention, the amount of metal around the second common mode filter unit 19 is increased by the metal layer 24, so the second common mode filter unit. Since the metal amount of 19 can be made close to the metal amount of the first common mode filter portion 18, it is possible to prevent the insulating layer around the second common mode filter portion 19 from contracting. The outer shape of the laminate 22 can be prevented from being deformed, and as a result, the occurrence of external electrode formation defects and mounting defects can be suppressed.

  Further, as shown in FIG. 5, the spiral metal layer 24 may be formed on the outer portion (downward) of the second and fourth coil conductors 15 and 17 in the stacking direction.

  At this time, the metal layer 24 may be formed so as to overlap the second and fourth coil conductors 15 and 17 in a top view. Thus, the stray capacitance C between the metal layer 24 and the second common mode filter unit 19 and the L component of the second common mode filter unit 19 resonate at a specific frequency. Common mode noise can be removed at two frequencies of the resonance frequency of the two common mode filter sections 18 and 19.

  Or you may form so that it may not overlap with the 2nd, 4th coil conductors 15 and 17 in top view. Thereby, the magnetic flux circulates without being obstructed by the metal layer 24, and the coupling between the second coil conductor 15 and the fourth coil conductor 17 is strengthened, so that the attenuation characteristic of the second common mode filter unit 19 is increased. Can be prevented from deteriorating.

  The outermost layer of the metal layer 24 is substantially the same as the outermost portion of the first and third coil conductors in a top view, or as long as it is exposed from the first and third coil conductors. It does not necessarily have to be spiral.

  And as shown in FIG. 6, you may make the width | variety of the metal layer 24 wider than the 2nd, 4th coil conductors 15 and 17. As shown in FIG.

  As shown in FIG. 7, the metal layer 24 may be plate-shaped instead of spiral in the outer portion (downward) in the stacking direction of the second and fourth coil conductors 15, 17. Therefore, the effect of preventing the insulating layer around the second common mode filter unit 19 from shrinking can be further enhanced.

  The metal layer 24 may be connected to the ground. Since the stray capacitance is generated between the second common mode filter unit 19, the attenuation characteristic is improved.

  Further, the metal layer 24 may be connected to the second and fourth coil conductors 15 and 17. The attenuation characteristics are improved by the stray capacitance generated between the metal layer 24 and the second and fourth coil conductors 15 and 17.

  Further, as shown in FIG. 8, the widths of the second and fourth coil conductors 15 and 17 may be wider than the widths of the first and third coil conductors 14 and 16. The amount of metal in the second common mode filter portion 19 can be increased without forming metal separately.

  In the first and second embodiments of the present invention described above, the first and second coil conductors 14 and 15 constituting the first coil 12 and the third and fourth coils constituting the second coil 13 are used. Although the conductors 16 and 17 are alternately arranged, the second coil conductor 15 and the fourth coil conductor 17 are interchanged, and the third coil conductor 16 and the fourth coil constituting the second coil 13 are exchanged. These coil conductors 17 may be arranged so as to be sandwiched between the first coil conductor 14 and the second coil conductor 15 constituting the first coil 12.

  Further, all the first to seventh insulator layers 11a to 11g are made of a non-magnetic material, and the laminated body 22 is made of only a non-magnetic layer without containing a magnetic substance, so that more attenuation is achieved at a characteristic frequency. You may make it obtain quantity.

  The common mode noise filter according to the present invention has an effect of suppressing the occurrence of external electrode formation defects and mounting defects, and in particular, noise of various electronic devices such as digital devices, AV devices, and information communication terminals. It is useful in a small and thin common mode noise filter used as a countermeasure.

11a to 11g 1st to 7th insulator layers 12 1st coil 13 2nd coil 14 1st coil conductor 15 2nd coil conductor 16 3rd coil conductor 17 4th coil conductor 18 1st Common mode filter unit 19 Second common mode filter unit 21 Constraining layer 24 Metal layer

Claims (10)

A plurality of laminated insulator layers; first and second coils formed on the insulator layer; and a laminate comprising the insulator layer and the first and second coils, The first coil is composed of a spiral first coil conductor and a second coil conductor, and the second coil is composed of a spiral third coil conductor and a fourth coil conductor, and the second coil The third coil conductor and the fourth coil conductor constituting the first coil are arranged so as to be sandwiched between the first coil conductor and the second coil conductor constituting the first coil, or the first coil is arranged The first and second coil conductors constituting the second coil conductor and the third and fourth coil conductors constituting the second coil are alternately arranged, and the first coil conductor and the third coil conductor are magnetically arranged. To form a first common mode filter portion, A second common mode filter unit is formed by magnetically coupling the coil conductor and the fourth coil conductor, the first common mode filter unit and the second common mode filter unit are connected in series, and The number of turns of the second and fourth coil conductors in the second common mode filter unit is less than the number of turns of the first and third coil conductors in the first common mode filter unit, and at least the second A common mode noise filter in which a constraining layer having a shrinkage rate smaller than that of the insulator layer is provided around the fourth coil conductor or in an outer portion in the stacking direction of the second and fourth coil conductors. A plurality of laminated insulator layers; first and second coils formed on the insulator layer; and a laminate comprising the insulator layer and the first and second coils, The first coil is composed of a spiral first coil conductor and a second coil conductor, and the second coil is composed of a spiral third coil conductor and a fourth coil conductor, and the second coil The third coil conductor and the fourth coil conductor constituting the first coil are arranged so as to be sandwiched between the first coil conductor and the second coil conductor constituting the first coil, or the first coil is arranged The first and second coil conductors constituting the second coil conductor and the third and fourth coil conductors constituting the second coil are alternately arranged, and the first coil conductor and the third coil conductor are magnetically arranged. To form a first common mode filter portion, A second common mode filter unit is formed by magnetically coupling the coil conductor and the fourth coil conductor, the first common mode filter unit and the second common mode filter unit are connected in series, and The number of turns of the second and fourth coil conductors in the second common mode filter unit is less than the number of turns of the first and third coil conductors in the first common mode filter unit, and the second, A common mode noise filter in which a metal layer is provided around a fourth coil conductor or on an outer portion in the stacking direction of the second and fourth coil conductors. The common mode noise filter according to claim 2, wherein the metal layer is formed of a spiral metal. The spiral metal formed in the outer portion of the second and fourth coil conductors in the stacking direction is formed so as to overlap the second and fourth coil conductors in a top view. Common mode noise filter. The spiral metal formed in the outer portion in the stacking direction of the second and fourth coil conductors is formed so as not to overlap the second and fourth coil conductors in a top view. Common mode noise filter. The common mode noise filter according to claim 2, wherein the metal layer is made of a plate-like metal. The common mode noise filter according to claim 2, wherein the metal layer is connected to a ground. The common mode noise filter according to claim 2, wherein the metal layer is connected to the second and fourth coil conductors. The common mode noise filter according to claim 2, wherein the metal layer is exposed from the first and third coil conductors in a top view. A plurality of laminated insulator layers; first and second coils formed on the insulator layer; and a laminate comprising the insulator layer and the first and second coils, The first coil is composed of a spiral first coil conductor and a second coil conductor, and the second coil is composed of a spiral third coil conductor and a fourth coil conductor, and the second coil The third coil conductor and the fourth coil conductor constituting the first coil are arranged so as to be sandwiched between the first coil conductor and the second coil conductor constituting the first coil, or the first coil is arranged The first and second coil conductors constituting the second coil conductor and the third and fourth coil conductors constituting the second coil are alternately arranged, and the first coil conductor and the third coil conductor are magnetically arranged. To form a first common mode filter portion, A second common mode filter unit is formed by magnetically coupling the coil conductor and the fourth coil conductor, the first common mode filter unit and the second common mode filter unit are connected in series, and The number of turns of the second and fourth coil conductors in the second common mode filter unit is less than the number of turns of the first and third coil conductors in the first common mode filter unit, and the second, A common mode noise filter in which a line width of a fourth coil conductor is wider than a line width of the first and third coil conductors.

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