1. Field of the Invention
The invention relates to an inductor element, and particularly relates to an inductor element used as an antenna coil for short-range radio communication.
2. Background Art
An element is known in which as in a coil element disclosed in Patent Document 1, a coil pattern is wound on the outer periphery of a multilayer body, namely, a magnetic material, by stacking magnetic sheets having the coil pattern printed on a principal surface thereof. In such an element, in order to prevent short-circuiting of the coil pattern, the multilayer body is coated with a non-magnetic sheet as an outermost layer. Furthermore, in order to reduce a direct current resistance component of the coil pattern, a line conductor connected in parallel with the coil pattern is provided within the non-magnetic sheet.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-49737
However, if the line conductor is provided in the non-magnetic sheet, the height of the inductor element is increased. On the other hand, if the thickness of the non-magnetic sheet is decreased in order to decrease the height of the inductor element, an end portion of the non-magnetic sheet is ground in a process of manufacturing the inductor element (in particular, a barrel polishing step), and the conductor may be broken.
Therefore, a main object of the invention is to provide an inductor element which is able to reduce a risk of breaking a conductor.
An inductor element (1: corresponding to a reference sign in an embodiment. The same applies hereinafter) includes: a magnetic layer (12b); a first line conductor (20, 20, . . . ) provided on one principal surface of the magnetic layer; a second line conductor (18, 18, . . . ) provided on another principal surface of the magnetic layer; a side conductor (34a, 34a, . . . , 34b, 34b, . . . ) provided on a side surface of the magnetic layer to connect the first line conductor and the second line conductor in a coil shape; a first non-magnetic layer (12c) stacked at one principal surface side of the magnetic layer; a second non-magnetic layer (12a) stacked at another principal surface side of the magnetic layer; a third line conductor (22, 22, . . . ) provided within the first non-magnetic layer; a fourth line conductor (16, 16, . . . ) provided within the second non-magnetic layer; a first connection conductor (32a, 32a, . . . , 32b, 32b, . . . ) provided within the first non-magnetic layer to connect the third line conductor in parallel with the first line conductor; and a second connection conductor (30a, 30a, . . . , 30b, 30b, . . . , 36a, 36a, . . . , 36b, 36b, . . . ) provided within the second non-magnetic layer or on a side surface of the second non-magnetic layer to connect the fourth line conductor in parallel with the second line conductor.
Preferably, the third line conductor is provided so as to overlap the first line conductor as seen from a stacking direction, and the first connection conductor corresponds to a via-hole conductor extending along the stacking direction.
Preferably, the second connection conductor is formed within the second non-magnetic layer.
Further preferably, the fourth line conductor is provided so as to overlap the second line conductor as seen from the stacking direction, and the second connection conductor corresponds to a via-hole conductor extending along the stacking direction.
Preferably, the first line conductor has a first pattern, and the second line conductor has a second pattern different from the first pattern.
Preferably, the magnetic layer includes a plurality of stacked sheets (SH3, SH4) each having a magnetic material, the first non-magnetic layer includes a plurality of stacked sheets (SH5, SH6) each having a non-magnetic material, and the second non-magnetic layer includes a plurality of stacked sheets (SH0, SH1, SH2) each having the non-magnetic material.
According to the invention, a direct current resistance component of an inductor is reduced since the line conductor provided within the non-magnetic layer is connected in parallel with the line conductor provided on the magnetic layer and the line conductor provided within the other non-magnetic layer is connected in parallel with the other line conductor provided on the magnetic layer. Here, at least one of the two connection conductors for parallel connection is provided within the non-magnetic layer. Accordingly, a risk is reduced that the line conductor or the connection conductor provided within the non-magnetic layer is broken in a manufacturing process.
The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description of embodiments of the invention with reference to the accompanying drawings.
With reference to
The long sides and the short sides of a rectangular forming a principal surface of the multilayer body 12 extend along an X axis and a Y axis, respectively, and the thickness of the multilayer body 12 increases along a Z axis. Conductive terminals 14a and 14b are provided on a lower surface of the multilayer body 12 and at positions corresponding to both ends thereof in an X-axis direction.
The sizes of the principal surfaces of the ceramic sheets SH0 to SH6 are the same. The material of the ceramic sheets SH0 to SH2, SH5, and SH6 is a non-magnetic (relative permeability: 1) ferrite, and the material of the ceramic sheets SH3 and SH4 is a magnetic (relative permeability: 100 to 120) ferrite. Furthermore, one principal surface and the other principal surface of the multilayer body 12 or each of the ceramic sheets SH0 to SH6 is referred to as “upper surface” and “lower surface” as necessary.
As shown in
It should be noted that no line conductor is present on the upper surface of the ceramic sheet SH3, and the magnetic material appears on the entire upper surface. Similarly, no line conductor is present also on the upper surfaces of the non-magnetic sheets SH0 and SH6, and the non-magnetic material appears on the entire upper surfaces.
With reference to
With reference to
With reference to
With reference to
The arrangement of the line conductors 16 on the ceramic sheet SH1 coincides with the arrangement of the line conductors 18 on the ceramic sheet SH2 except for both side portions in the Y-axis direction. Therefore, the line conductors 16 overlap the line conductors 18 when being seen from a Z-axis direction. Similarly, the arrangement of the line conductors 22 on the ceramic sheet SH5 coincides with the arrangement of the line conductors 20 on the ceramic sheet SH4 except for both side portions in the Y-axis direction. Therefore, the line conductors 22 overlap the line conductors 20 when being seen from the Z-axis direction.
In addition, the distance in the X-axis direction from one end to the other end of each line conductor 18 provided on the ceramic sheet SH2 corresponds to “D1”, and the interval between the two adjacent line conductors 20 on the ceramic sheet SH4 also corresponds to “D1”.
Furthermore, the position of the one end of each line conductor 18 is adjusted to a position which overlaps one end of the line conductor 20 as seen from the Z-axis direction, and the position of the other end of each line conductor 18 is adjusted to a position which overlaps the other end of the line conductor 20 as seen from the Z-axis direction. In addition, the number of the line conductors 18 is smaller than the number of the line conductors 20 by one.
Therefore, when being seen from the Z-axis direction, the line conductors 18 and 20 are arranged alternately in the X-axis direction. In addition, the one end of each line conductor 18 overlaps the one end of the line conductor 20, and the other end of each line conductor 18 overlaps the other end of the line conductor 20.
Plate-shaped conductors 24a and 24b are additionally formed on the upper surface of the ceramic sheet SH1. Similarly, plate-shaped conductors 26a and 26b are also formed on the upper surface of the ceramic sheet SH2. The plate-shaped conductors 24a and 26a are provided at a position which is slightly at the negative side of a positive side end portion in the X-axis direction and corresponds to a positive side end portion in the Y-axis direction. In addition, the plate-shaped conductors 24b and 26b are provided at a position which is slightly at the positive side of a negative side end portion in the X-axis direction and corresponds to a negative side end portion in the Y-axis direction.
The distance in the X-axis direction from one end of the line conductor 18 present at the most positive side to the plate-shaped conductor 26a corresponds to “D1”, and the distance in the X-axis direction from the other end of the line conductor 18 present at the most negative side to the plate-shaped conductor 26b also corresponds to “D1” . In addition, when being seen from the Z-axis direction, the plate-shaped conductors 24a and 24b overlap the plate-shaped conductors 26a and 26b, respectively.
As shown in
With further reference to
The number of the side conductors 34a coincides with the number of the line conductors 20, and the number of the side conductors 34b also coincides with the number of the line conductors 20. In addition, the side conductors 34a or 34b are arranged so as to be spaced apart from each other at distances D1 in the X-axis direction. Furthermore, the side conductor 34a present at the most positive side in the X-axis direction is connected to the plate-shaped conductor 26a, and the side conductor 34b present at the most negative side in the X-axis direction is connected to the plate-shaped conductor 26b.
Therefore, a coil conductor (wound body) is formed by the line conductors 18 formed on the ceramic sheet SH2, the line conductors 20 formed on the ceramic sheet SH4, and the side conductors 34a and 34b. Since the magnetic material is present at the inner side of the coil conductor, the coil conductor serves as an inductor.
As shown in
Similarly, via-hole conductors 32a, 32a, . . . extend through the ceramic sheet SH5 in the Z-axis direction at the positions of one ends of the line conductors 22, 22, . . . . In addition, via-hole conductors 32b, 32b, . . . extend through the ceramic sheet SH5 in the Z-axis direction at the positions of the other ends of the line conductors 22, 22, . . . . The two line conductors 20 and 22 that overlap each other when being seen from the Z-axis direction are connected in parallel via the via-hole conductors 32a and 32b. The non-magnetic material is interposed between the line conductors 20 and 22 connected in parallel, and the direct current resistance component of the inductor is also reduced by the line conductors 22.
The ceramic sheet SH1 is manufactured in a manner shown in
Next, a plurality of through holes HL1, HL1, . . . are formed in the mother sheet BS1 so as to correspond to the vicinities of intersections of the broken lines (see
It should be noted that the ceramic sheet SH0 is manufactured by forming, in a motherboard, the same through holes as the through holes HL1 shown in
The ceramic sheet SH2 is manufactured in a manner shown in
Next, a plurality of through holes HL2, HL2, . . . are formed in the mother sheet BS2 so as to correspond to positions at both sides of the broken lines extending in the X-axis direction (see
The ceramic sheet SH3 is manufactured in a manner shown in
The ceramic sheet SH4 is manufactured in a manner shown in
Next, a plurality of through holes HL4, HL4, . . . are formed in the mother sheet BS4 along the broken lines extending in the X-axis direction (see
The ceramic sheet SH5 is manufactured in a manner shown in
Next, a plurality of through holes HL5, HL5, . . . are formed in the mother sheet BS5 so as to correspond to positions at both sides of the broken lines extending in the X-axis direction (see
The mother sheets BS1 to BS5 having been subjected to the above-described steps, a mother sheet BS0 corresponding to the ceramic sheet SH0, and a mother sheet BS6 corresponding to the ceramic sheet SH6 are press-bonded to each other in a state of being stacked in a manner shown in
The press-bonded multilayer body is cut along the above broken lines into pieces by being prior to burning (see
As is understood from the above description, the line conductors 20 are provided on one principal surface of the magnetic layer 12b, and the line conductors 18 are provided on the other principal surface of the magnetic layer 12b. In addition, the side conductors 34a and 34b are provided on the side surfaces of the magnetic layer 12b to connect the line conductors 18 and 29 in a coil shape. The non-magnetic layer 12c is stacked at the one principal surface side of the magnetic layer 12b, and the non-magnetic layer 12a is stacked at the other principal surface side of the magnetic layer 12b. The line conductors 22 are provided within the non-magnetic layer 12c, and the line conductors 16 are provided within the non-magnetic layer 12a. The via-hole conductors 32a and 32b are provided within the non-magnetic layer 12c to connect the line conductors 22 in parallel with the line conductors 20. In addition, the via-hole conductors 30a and 30b are provided within the non-magnetic layer 12a to connect the line conductors 16 in parallel with the line conductors 18.
The direct current resistance component of the inductor is reduced by connecting the line conductors 22, which are provided within the non-magnetic layer 12c, in parallel with the line conductors 20, which are provided on the one principal surface of the magnetic layer 12b, and connecting the line conductors 16, which are provided within the non-magnetic layer 12a, in parallel with the line conductors 18, which are provided on the other principal surface of the magnetic layer 12b.
Here, the via-hole conductors 32a and 32b for connecting the line conductors 20 and 22 in parallel are provided within the non-magnetic layer 12c, and the via-hole conductors 30a and 30b for connecting the line conductors 16 and 18 in parallel are also provided within the non-magnetic layer 12a. Accordingly, a risk is reduced that the conductors provided to the non-magnetic layer 12a or 12c are broken in the manufacturing process (barrel polishing).
In the embodiment, the line conductors 16 provided within the non-magnetic layer 12a are connected in parallel with the line conductors 18 on the magnetic layer 12b via the via-hole conductors 30a and 30b. However, as shown in
In addition, in the embodiment, whereas the line conductors 18 extend in the oblique direction with respect to the Y axis, the line conductors 20 extend in the Y-axis direction. However, the directions in which the line conductors 18 and 20 extend may be different from those in the embodiment as long as the line conductors 18 and 20 are connected in a coil shape via the side conductors 34a and 34b.
Furthermore, in the embodiment, the plate-shaped conductors 24a and 26a are connected to the conductive terminal 14a via the via-hole conductor 28a, and the plate-shaped conductors 24b and 26b are connected to the conductive terminal 14b via the via-hole conductor 28b (see
10 antenna coil element
SH0 to SH6 ceramic sheet
12
a, 12c non-magnetic layer
12
b magnetic layer
16, 18, 20, 22 line conductor
28
a, 28b, 30a, 30b, 32a, 32b via-hole conductor
34
a, 34b, 36a, 36b side conductor
Number | Date | Country | Kind |
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2012-211441 | Sep 2012 | JP | national |
Number | Date | Country | |
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Parent | PCT/JP2013/068006 | Jul 2013 | US |
Child | 14621771 | US |