JP2009246148A - Common mode noise filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common mode noise filter capable of being used in a high frequency band. <P>SOLUTION: The common mode noise filter comprises a first coil 16 formed by connecting a first conductor 11 with a second conductor 12 thorough a first via electrode 15a; and a second coil 17 formed by connecting a third conductor 13 with a fourth conductor 14 thorough a second via electrode 15b. The second conductor 12 and the third conductor 13 are spirally formed with one or more turns and are opposed each other. At least two magnetic layers 18 are provide above and under the first and the second coils 16, 17 respectively, and low dielectric layers 19 containing glass are disposed between two magnetic layers 18 and between an upper magnetic layer 18 and a lower magnetic layer 18. The first conductor 11 and the fourth conductor 14 are spirally formed with less than one turn. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  As shown in FIG. 5, the conventional common mode noise filter of this type includes first to fourth conductors 1 to 4, the first conductor 1 and the second conductor 2, and a first via electrode 5a. The second coil provided by connecting the first coil 6 provided by connection via the third conductor 3 and the fourth conductor 4 via the second via electrode 5b. A coil 7, the second conductor 2 and the third conductor 3 have a spiral shape and are opposed to each other, while the first conductor 1 and the fourth conductor 4 have a linear shape. A plurality of magnetic layers 8 are provided above and below the first and second coils 6 and 7, respectively, and between the plurality of magnetic layers 8 and between the upper magnetic layer 8 and the lower magnetic layer. The low dielectric constant layer 9 containing glass is provided between 8.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2006-319209 A

  In the conventional common mode noise filter described above, when the thickness is reduced, the distance between the ground on the back surface of the mounting substrate and the first and second coils 6 and 7 is shortened. The stray capacitance between the coils 6 and 7 increases, thereby reducing the inductance for the differential signal in the high frequency band, and thus the insertion loss of the differential signal in the high frequency band increases. As a result, the high frequency band There was a problem that it would be difficult to use in Japan.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a common mode noise filter that can be used in a high frequency band.

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

  According to the first aspect of the present invention, the first to fourth conductors are provided by connecting the first conductor and the second conductor via the first via electrode. And a second coil provided by connecting the third conductor and the fourth conductor via a second via electrode, and the second conductor and the third conductor. The shape is a spiral of 1 turn or more and is opposed to each other, and is provided with at least two magnetic layers above and below the first and second coils, respectively, and the two magnetic layers and the upper A low dielectric constant layer containing glass is provided between the magnetic layer and the lower magnetic layer, and the shape of the first conductor and the fourth conductor is a spiral shape of less than one turn. According to the first conductor and the fourth conductor, which are spirally formed with less than one turn, Since the inductance of the differential signal in the high frequency band can be compensated for by this, it is possible to compensate for the increase in the insertion loss of the differential signal in the high frequency band. The effect that it can be used in is obtained.

  According to a second aspect of the present invention, the first to fourth conductors are provided by connecting the first conductor and the second conductor via the first via electrode. And a second coil provided by connecting the third conductor and the fourth conductor via a second via electrode, and the second conductor and the third conductor The shape is a spiral of 1 turn or more and is opposed to each other, and is provided with at least two magnetic layers above and below the first and second coils, respectively, and the two magnetic layers and the upper A low dielectric constant layer containing glass is provided between the magnetic layer and the lower magnetic layer, and the width of the first conductor and the fourth conductor is smaller than the width of the second conductor and the third conductor. Therefore, according to this configuration, the first conductor and the fourth conductor having a small width are constant. Since the inductance is obtained, it is possible to compensate for the decrease in inductance with respect to the differential signal in the high frequency band, thereby preventing an increase in the insertion loss of the differential signal in the high frequency band. It is possible to obtain the operational effect that the use of can be performed.

  According to a third aspect of the present invention, the first to fourth conductors are provided by connecting the first conductor and the second conductor via the first via electrode. And a second coil provided by connecting the third conductor and the fourth conductor via a second via electrode, and the second conductor and the third conductor The shape is a spiral of 1 turn or more and is opposed to each other, and at least two magnetic layers are provided below the second conductor and above the third conductor, respectively, and the two magnetic layers, and A low dielectric constant layer containing glass is provided between the upper magnetic layer and the lower magnetic layer, and the first conductor and the fourth conductor are further provided between the two magnetic layers. According to this configuration, the first via electrode and the second via electrode are formed of two sheets. Since the first via electrode and the second via electrode provide a certain inductance, it is possible to compensate for the reduced inductance for the differential signal in the high frequency band. As a result, it is possible to prevent an increase in the insertion loss of the differential signal in the high frequency band, so that an effect of enabling use in the high frequency band can be obtained.

  As described above, in the common mode noise filter of the present invention, a constant inductance is obtained by the first conductor and the fourth conductor or the first via electrode and the second via electrode. This can compensate for the decrease in the inductance of the differential signal, thereby preventing an increase in the insertion loss of the differential signal in the high frequency band, so that it can be used in the high frequency band. There is an effect.

(Embodiment 1)
Hereinafter, the first and second aspects of the present invention will be described with reference to the first and second aspects of the present invention.

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

  As shown in FIG. 1, the common mode noise filter according to one embodiment of the present invention is configured to connect the first to fourth conductors 11 to 14, the first conductor 11, and the second conductor 12 to the first one. Provided by connecting the first coil 16 provided by connecting via the via electrode 15a, the third conductor 13 and the fourth conductor 14 via the second via electrode 15b. The second coil 17 is provided. The second conductor 12 and the third conductor 13 have a spiral shape of one turn or more and are opposed to each other, and at least above and below the first and second coils 16 and 17, respectively. Two magnetic layers 18 are provided, and a low dielectric constant layer 19 containing glass is provided between the two magnetic layers 18 and between the upper magnetic layer 18 and the lower magnetic layer 18, and The shapes of the first conductor 11 and the fourth conductor 14 are spirals of less than one turn.

  In the above configuration, the first to fourth conductors 11 to 14 are formed by plating a conductive material such as silver, and the first conductor 11 is formed on the upper surface of the magnetic layer 18, and second The fourth conductors 12 to 14 are formed on the upper surfaces of the different low dielectric constant layers 19. Further, the first conductor 11 and the second conductor 12 are connected via a first via electrode 15 a to constitute a first coil 16. The third conductor 13 and the fourth conductor 14 are connected via a second via electrode 15 b to constitute a second coil 17. Further, the first and second via electrodes 15a and 15b are formed by filling holes penetrating the low dielectric constant layer 19 with a conductive material such as silver.

  The first conductor 11 and the fourth conductor 14 have a spiral shape of less than one turn, and the second conductor 12 and the third conductor 13 have a spiral shape of about 7 turns. The second conductor 12 and the third conductor 13 substantially overlap each other when viewed from above.

  The magnetic layer 18 has an insulating property and is made of a magnetic material such as Ni—Zn ferrite. The magnetic layer 18 is further below the first coil 16 and above the second coil 17. Three are provided. The number of magnetic layers 18 provided below the first coil 16 or above the second coil 17 is not limited to three, and may be any other number as long as it is two or more. .

  The low dielectric constant layer 19 is made of an insulating material having a low magnetic permeability and containing glass such as glass ceramic. Further, the low dielectric constant layer 19 is located below the first coil 16. Between the magnetic layer 18 and the magnetic layer 18, between the magnetic layer 18 and the magnetic layer 18 positioned above the second coil 17, and below the first coil 16 and the second magnetic layer 18. The magnetic layer 18 located above the coil 17 is provided. A plurality of low dielectric constant layers 19 provided between the magnetic layer 18 positioned below the first coil 16 and the magnetic layer 18 positioned above the second coil 17 are formed, and Second to fourth conductors 12 to 14 are provided on the upper surface. That is, the low dielectric constant layer 19 is sandwiched between the two magnetic layers 18 below the first coil 16 and above the second coil 17, and the first and second coils 16 and 17 are formed. A plurality of low dielectric constant layers 19 are sandwiched between an upper magnetic layer 18 and a lower magnetic layer 18. The number of the low dielectric constant layers 19 is not limited to the number shown in FIG.

  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 at both ends 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 that it may be connected with each one end part of the conductors 11-14, respectively. 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 11 to 14 are not formed by plating, but may be formed by other methods such as printing or vapor deposition.

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

  1 and 2, first, a predetermined number of rectangular magnetic layers 18 and low dielectric constant layers 19 are respectively produced from a mixture of magnetic materials, glass, ceramic powder, and resin as raw materials. At this time, a hole is formed in a predetermined portion of each of the two low dielectric constant layers 19 by laser, punching, or the like, and the hole is filled with silver, so that the first and second via electrodes 15a and 15b are formed. Form.

  Next, the magnetic layer 18, the low dielectric constant layer 19, the magnetic layer 18, the low dielectric constant layer 19, and the magnetic layer 18 are laminated in this order.

  Next, a spiral first conductor 11 having less than one turn is formed on the upper surface of the magnetic layer 18 by plating.

  Next, a low dielectric constant layer 19 having a first via electrode 15 a is laminated on the upper surface of the first conductor 11. At this time, the first conductor 11 and the first via electrode 15a are connected.

  Next, the second conductor 12 is formed in a spiral shape on the upper surface of the low dielectric constant layer 19 by plating. At this time, the second conductor 12 and the first via electrode 15a are connected. Thereafter, a low dielectric constant layer 19 is laminated on the upper surface of the second conductor 12.

  Next, the third conductor 13 is formed in a spiral shape on the upper surface of the low dielectric constant layer 19 by plating.

  Next, the low dielectric constant layer 19 having the second via electrode 15 b is laminated on the upper surface of the third conductor 13. At this time, the third conductor 13 and the second via electrode 15b are connected.

  Next, a spiral fourth conductor 14 of less than one turn is formed on the upper surface of the low dielectric constant layer 19 by plating. At this time, the fourth conductor 14 and the second via electrode 15b are connected.

  In addition, the formation method of the said 1st-4th conductors 11-14 forms the conductor of a predetermined pattern shape by plating on the base plate (not shown) prepared separately, and transcribe | transfers this conductor to each layer after that. To form.

  Next, the magnetic layer 18, the low dielectric constant layer 19, the magnetic layer 18, the low dielectric constant layer 19, and the magnetic layer 18 are laminated in this order on the upper surface of the fourth conductor 14, and the main part of the common mode noise filter 21 is formed.

  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 11 to 14. 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 first embodiment of the present invention, the first conductor 11 and the fourth conductor 14 having a spiral shape of less than one turn have a certain inductance (the first conductor 11 and the fourth conductor 14). Can be compensated for the reduced inductance for the differential signal in the high-frequency band, which reduces the insertion loss of the differential signal in the high-frequency band. Since the increase can be prevented, the effect that it can be used in a high frequency band can be obtained.

  That is, in the common mode noise filter according to the first embodiment of the present invention, when the thickness is reduced, the distance between the ground on the back surface of the mounting substrate and the first and second coils 16 and 17 is shortened. Although the stray capacitance between the first and second coils 16 and 17 increases, even in this case, the first conductor 11 and the fourth conductor 14 appear as shown in FIG. Since another coil L1 having a certain inductance is formed, the inductance for the differential signal in the high frequency band does not decrease, and as a result, the insertion loss of the differential signal in the high frequency band does not increase. It can be used in a high frequency band. In addition, since the insertion loss of the differential signal in the high frequency band does not increase, signal waveform distortion can be prevented.

  When the first conductor 11 and the fourth conductor 14 have a spiral shape of one turn or more, that is, when the number of turns of the second conductor 12 and the third conductor 13 is equal to or more than that, Since the impedance of the differential signal is increased, the effect of removing common mode noise is reduced, which is not preferable.

  In the common mode noise filter according to the first embodiment of the present invention, the first conductor 11 and the fourth conductor 14 have a spiral shape of less than one turn in order to obtain a certain inductance. The widths of the conductor 11 and the fourth conductor 14 may be smaller than the widths of the second conductor 12 and the third conductor 13.

(Embodiment 2)
The second aspect of the present invention will be described below with reference to the second embodiment.

  FIG. 4 is an exploded perspective view of the 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.

  In FIG. 4, the second embodiment of the present invention is different from the first embodiment of the present invention described above in that the first conductor 11 and the fourth conductor 14 are replaced by the second conductor 12 and the third conductor. 13 is formed on a low dielectric constant layer 19 provided between two magnetic layers 18 located above and below 13.

  In this case, the first and second via electrodes 15 a and 15 b are formed so as to penetrate not only the low dielectric constant layer 19 but also the magnetic layer 18.

  With the above configuration, since the first via electrode 15a and the second via electrode 15b penetrate the magnetic layer 18, a constant inductance is obtained by the first via electrode 15a and the second via electrode 15b. As a result, it is possible to compensate for the reduced inductance of the differential signal in the high frequency band, and as a result, it is possible to prevent an increase in the insertion loss of the differential signal in the high frequency band. The effect that use becomes possible is acquired.

  In FIG. 4, the first conductor 11 and the fourth conductor 14 are formed between the magnetic layer 18 and the low dielectric constant layer 19, but the first dielectric 11 is formed inside the low dielectric constant layer 19. The conductor 11 and the fourth conductor 14 may be embedded.

  Further, as in the first embodiment of the present invention described above, a width smaller than the width of the spiral first conductor 11 and the fourth conductor 14 or the second conductor 12 and the third conductor 13 of less than one turn. The first conductor 11 and the fourth conductor 14 are made of two magnetic layers positioned above and below the second conductor 12 and the third conductor 13 as in the second embodiment of the present invention described above. If formed in the low dielectric constant layer 19 provided between the first conductor 11, the fourth conductor 14, the first via electrode 15a, and the second via electrode 15b, a larger inductance can be obtained. .

  In the common mode noise filter according to the first and second embodiments of the present invention, a pair of coils 16 and 17 has been described. However, two or more pairs of coils may be formed to form an array type. is there.

  The common mode noise filter according to the present invention has an effect that it can be used in a high frequency band, 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 a mode noise filter or the like.

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 Equivalent circuit diagram of the common mode noise filter The disassembled perspective view of the common mode noise filter in Embodiment 2 of this invention Exploded perspective view of a conventional common mode noise filter

Explanation of symbols

11-14 First to fourth conductors 15a First via electrode 15b Second via electrode 16 First coil 17 Second coil 18 Magnetic layer 19 Low dielectric constant layer

Claims (3)

A first coil provided by connecting the first to fourth conductors, the first conductor and the second conductor via a first via electrode, the third conductor and the fourth conductor; A second coil provided by connecting the second conductor and the second conductor via a second via electrode, the second conductor and the third conductor having a spiral shape of one turn or more, and each other At least two magnetic layers are provided above and below each of the first and second coils, and glass is provided between the two magnetic layers and between the upper magnetic layer and the lower magnetic layer. A common mode noise filter in which a low-dielectric constant layer containing bismuth is provided, and the shape of the first conductor and the fourth conductor is a spiral of less than one turn. A first coil provided by connecting the first to fourth conductors, the first conductor and the second conductor via a first via electrode, the third conductor and the fourth conductor; A second coil provided by connecting the second conductor and the second conductor via a second via electrode, the second conductor and the third conductor having a spiral shape of one turn or more, and each other At least two magnetic layers are provided above and below each of the first and second coils, and glass is provided between the two magnetic layers and between the upper magnetic layer and the lower magnetic layer. A common mode noise filter in which a low-dielectric constant layer is provided, and the width of the first conductor and the fourth conductor is smaller than the width of the second conductor and the third conductor. A first coil provided by connecting the first to fourth conductors, the first conductor and the second conductor via a first via electrode, the third conductor and the fourth conductor; A second coil provided by connecting the second conductor and the second conductor via a second via electrode, the second conductor and the third conductor having a spiral shape of one turn or more, and each other At least two magnetic layers are provided opposite to each other below the second conductor and above the third conductor, and between the two magnetic layers and between the upper magnetic layer and the lower magnetic layer. A common mode noise filter in which a low dielectric constant layer containing glass is provided, and the first conductor and the fourth conductor are formed in a low dielectric constant layer provided between the two magnetic layers.

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