JP3176545B2 - Multilayer inductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor utilizing an electromagnetic induction phenomenon, and more particularly, to a laminated inductor having an internal conductor formed by lamination. More specifically, the present invention relates to a chip-type multilayer inductor, and more specifically, the present invention relates to a structure of an internal conductor in a multilayer chip inductor.

[0002]

2. Description of the Related Art In recent years, very small multilayer inductors, in which coil-shaped internal conductors are formed by lamination, so-called multilayer chip inductors, are widely known. This multilayer chip inductor has, for example, a chip size of 2.0 × 1.25 (mm) and a number of coil turns of 5 turns.

[0003] The structure of a conventional chip-type multilayer inductor is
This is shown schematically in FIG. As is clear from the figure, the multilayer inductor 51 is entirely made of a magnetic material such as ceramic or an insulator material, and the internal conductor 52 is formed in a coil shape in the multilayer inductor 51 by a manufacturing method described later. . The coil-shaped internal conductor 52 has, at one end, a lead-out conductor 53 at the beginning of winding, and at the other end, a lead-out conductor 54 at the end of winding. Multilayer inductor 5
External terminals 55 and 56 are respectively formed on the outer sides of both ends of 1. Note that the lead conductor 53 is connected to the external terminal 55 for connection to the circuit board.
Are connected to an external terminal 56.

FIG. 6A is an explanatory view for explaining one manufacturing process of the schematically shown laminated inductor 51, which is slightly different in shape, and FIG. FIG. 3 is a schematic cross-sectional view showing the manufactured laminated inductor 51 of the above.

In FIG. 6 (A), conventionally, two sheets of unprinted raw sheet 61 are placed one on top of the other, and then a raw sheet 62 with a lead-out conductor 54 is laminated on the raw sheet 61, A raw sheet 63 having a part of the internal conductor 52 is laminated, and another raw sheet 64 having a part of the internal conductor 52 is laminated on the raw sheet 63 as shown in the drawing. , 64 are repeated, and a raw sheet 65 with a lead conductor 53 is laminated on the last raw sheet 63, and the raw sheet 65
3 sheets of raw sheet 66 without printing are laminated on
The laminated inductor 51 was manufactured by pressure bonding and firing.

The laminated inductor 51 shown in FIG. 6 (B) is a closed magnetic circuit type laminated inductor.
That is, the magnetic flux 57 generated by the internal conductor 52 does not leak out of the laminated inductor 51.

[0007]

With respect to the multilayer chip inductor having the coil-shaped internal conductor as described above, attempts have been made to increase the Q of the chip-type multilayer inductor, that is, the Q of the coil. I have. In this case, Q is represented by Q = 2πf · L / R, where R is the resistance value, L is the inductance value, and f is the frequency.

Therefore, when increasing the Q of the coil, specifically, it is necessary to increase the thickness of the coil conductor in the laminated inductor or to increase the thickness of the coil conductor. By doing so, the resistance value R of the coil conductor is reduced, and Q can be improved.

However, increasing the thickness of the coil conductor causes a problem in that the entire inductor becomes large, which is contrary to the tendency of miniaturization to be a chip. Increasing the thickness of the coil conductor increases the danger that lamination displacement occurs during lamination or crimping, and lowers the accuracy of lamination. The present invention has been developed for the purpose of solving these problems.

[0010]

Means for Solving the Problems In the multilayer inductor of the present invention, a cylindrical internal conductor is formed by lamination, and each end of the internal conductor becomes a lead conductor, and
In the laminated inductor in which the pair of lead conductors are connected to both external terminals, at least the internal conductor has a plurality of layers having a ring-shaped conductor pattern,
And a plurality of layers having linear conductor patterns connecting the ring-shaped conductor patterns.

In one embodiment, the present invention is characterized in that the linear conductor pattern has an I shape. In another aspect, the present invention is characterized in that the linear conductor pattern has an = shape. In still another aspect, the present invention is characterized in that the linear conductor pattern has a + shape. In addition, in the present invention, preferably, the ring-shaped conductor pattern is □
It is characterized by being in the form of

[0012]

Therefore, according to the present invention, the conductor pattern of the internal conductor in the multilayer inductor can be increased in the form of sun, eyes, fields, etc., so that the conductor resistance of the entire multilayer inductor can be reduced. In addition, the resistance loss of the multilayer inductor is reduced, and the Q is greatly improved. According to the present invention, the conductor pattern of the inner conductor is
Although the magnetic path is made smaller in the form of eyes, fields, etc., the Q value can be greatly improved without substantially lowering the inductance value while maintaining substantially the same inductance value as the conventional example. .

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example with reference to the accompanying drawings, in which: FIG. FIG. 1 is a drawing showing one embodiment of a laminated inductor according to the present invention,
(A) is an explanatory view for explaining the manufacture, and (B) is a schematic cross-sectional view of the manufactured laminated inductor according to the first embodiment.
FIG. 2 is an explanatory view for manufacturing a second embodiment of the laminated inductor according to the present invention. FIG. 3 is a view showing a third embodiment of the multilayer inductor according to the present invention.
(A) is an explanatory view for explaining the manufacture, and (B) is a schematic cross-sectional view of the manufactured laminated inductor of the same. FIG. 4 is an explanatory view for manufacturing a fourth embodiment of the laminated inductor according to the present invention.

FIG. 1A is a view for explaining a manufacturing process of a laminated inductor according to an embodiment of the present invention. In the figure, first, two sheets of unprinted raw sheet 11 are placed one on top of the other, and then a raw sheet 12 having a mouth-shaped lead conductor 4 is laminated on this raw sheet 11, and the raw sheet 12 is A raw sheet 13 having a slightly large mouth-shaped conductor pattern 2a to be a part of the conductor 2 is laminated, and an I-shaped conductor pattern 2b to be a part of the inner conductor 2 is further added to the raw sheet 13. Another raw sheet 14 having a
3 and 14 are repeated and laminated, and the final raw sheet 13
Then, a raw sheet 15 having a mouth-shaped lead conductor 3 is laminated thereon, and three unprinted raw sheets 16 are laminated on the raw sheet 15, and then pressed and fired to obtain a laminated inductor 1. To manufacture.

Therefore, in this case, the internal conductor 2 looks sideways but looks like a sun when viewed from above in FIG. 1A. FIG. 1B is a schematic cross-sectional view of the laminated inductor 1 manufactured as above, and 7 in the figure indicates a magnetic flux.

The chip size of the manufactured laminated inductor 1 was 2.0 × 1.25 (mm), and the number of turns of the coil was 4 turns. When the characteristics of the multilayer inductor 1 shown in FIG. 1 were examined for 20 pieces, the average value of the inductance was 0.98 μH and the average value of the Q was 58.

FIG. 2 is a view for explaining a manufacturing process of a laminated inductor according to a second embodiment of the present invention. In the figure, first, two unprinted raw sheets 21 are placed one on top of the other, Then, a raw sheet 22 having a T-shaped lead conductor 4 is laminated on the raw sheet 21, and the raw sheet 22 has a mouth-shaped conductor pattern 2 a which becomes a part of the internal conductor 2. 23, and another raw sheet 24 having a one-shaped conductor pattern 2b, which becomes a part of the inner conductor 2, is laminated on the raw sheet 23, as shown in the drawing. 23 and 24 are repeatedly laminated, a raw sheet 25 having a T-shaped lead conductor 3 is laminated on the last raw sheet 23, and three raw sheets 26 without printing are laminated on this raw sheet 25. And then crimping It fired to, to produce a laminated inductor 1.

Therefore, in this case, the inner conductor is formed as shown in FIG.
When viewed from above, it looks like a sun. The chip size of the manufactured laminated inductor is 2.
0 × 1.25 (mm), and the number of turns of the coil was 4 turns. The characteristics of the multilayer inductor shown in FIG.
Examining about 0 pieces, the average value of the inductance is 0.
The average value of 95 μH and Q was 56.

FIG. 3A is for explaining a manufacturing process of a laminated inductor according to a third embodiment of the present invention. In the figure, first, raw sheet 3 without printing
2 are placed one on top of the other, and then the raw sheet 31 is laminated with the raw sheet 32 having the horizontal lead-shaped lead-out conductor 4, and becomes a part of the internal conductor 2 on this raw sheet 32.
A raw sheet 33 having a slightly large mouth-shaped conductor pattern 2a is laminated, and another raw sheet 34 having a = -shaped conductor pattern 2b to be a part of the internal conductor 2 is further added to the raw sheet 33. Laminate, as shown,
The raw sheets 33 and 34 are repeatedly laminated, and the final raw sheet 33 is laminated with the raw sheet 35 having the horizontal conductor L-shaped lead-out conductor 3, and the raw sheet 35 is printed with three unprinted raw sheets 36. The laminated inductor 1 is manufactured by press-bonding and firing. Accordingly, in this case, the inner conductor 2 looks sideways but looks like an eye when viewed from above in FIG. 3A.
FIG. 3B is a schematic cross-sectional view of the laminated inductor 1 manufactured as above, and 7 in the figure indicates a magnetic flux.

The chip size of the manufactured laminated inductor 1 was 2.0 × 1.25 (mm), and the number of turns of the coil was 4 turns. When the characteristics of the multilayer inductor 1 shown in FIG. 3 were examined for 20 pieces, the average value of the inductance was 0.95 μH and the average value of the Q was 61.

FIG. 4 is a view for explaining a manufacturing process of a laminated inductor according to a fourth embodiment of the present invention. In the figure, first, two sheets of unprinted raw sheets 41 are placed one on top of the other, Then, a raw sheet 42 having a horizontal earth-shaped lead conductor 4 is laminated on the raw sheet 41, and the raw sheet 42 has a mouth-shaped conductor pattern 2 a which becomes a part of the internal conductor 2. The sheet 43 is laminated, and another raw sheet 44 having a cross-shaped conductor pattern 2b, which becomes a part of the internal conductor 2, is laminated on the raw sheet 43, as shown in the drawing. Seats 43, 44
Is repeated, and a raw sheet 45 having a horizontal earth-shaped lead conductor 3 is laminated on the last raw sheet 43, and the raw sheet 4 without printing is placed on the raw sheet 45.
6 are laminated, then pressed and fired to produce a laminated inductor.

Therefore, in this case, the inner conductor
When viewed from above, it looks like a rice field. The chip size of the manufactured laminated inductor is 2.
0 × 1.25 (mm), and the number of turns of the coil was 4 turns. The characteristics of the multilayer inductor shown in FIG.
Examining about 0 pieces, the average value of the inductance is 0.
The average value of 93 μH and Q was 63.

Here, when the characteristics of the above-described conventional example and the characteristics of the four embodiments according to the present invention are collectively compared,
It is as shown in Table 1 below. In the conventional example, the values in Table 1 are:
It is an average value of 20 pieces.

[0024]

[Table 1]

As is clear from the table, when the conductor pattern of the internal conductor in the multilayer inductor is formed in the shape of a sun, an eye, a field, or the like, Q is greatly improved. In other words, when the conductor pattern of the internal conductor is increased as compared with the conventional multilayer inductor, the conductor resistance of the multilayer inductor as a whole is reduced, and as a result, the resistance loss of the multilayer inductor is reduced and Q is greatly improved. Will do.

Further, when the conductor pattern of the inner conductor is shaped like a sun, an eye, a field, etc. as in the embodiment, the area of the magnetic path is reduced, but the magnetic flux generated in the laminated inductor is divided. As a result, as shown in the table, almost the same inductance value as that of the conventional example is secured, in other words, the actual inductance value is reduced. The Q could be greatly improved without any decrease.

As can be seen from the table, in the case of the conductor pattern as in the embodiment, the inductance value is slightly lower than that of the conventional one. This is thought to be due to the fact that the inner conductor is enlarged by the conductor pattern as in the embodiment, and as a result, the magnetic path is reduced and the inductance value is slightly reduced. However, the decrease in the inductance value according to the present embodiment was slight, and the improvement in Q was remarkable.

[0028]

According to the present invention as described above, the Q of the laminated inductor is greatly increased by adding a simple structure in which the conductor pattern forming the internal conductor of the laminated inductor is shaped like a sun, an eye, a field, or the like. A great effect of being able to be improved is obtained. In other words, the present invention does not increase the thickness of the internal conductor, that is, while maintaining the tendency of miniaturization as a chip, and without increasing the thickness of the internal conductor, that is, maintaining the accuracy of lamination. There is an advantage that the Q of the multilayer inductor can be greatly improved while keeping the same.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a laminated inductor according to the present invention, wherein (A) is an explanatory view for explaining the production thereof,
(B) is a schematic cross-sectional view of the manufactured laminated inductor.

FIG. 2 is an explanatory view for manufacturing a second embodiment of the multilayer inductor according to the present invention.

3A and 3B are drawings showing a third embodiment of the multilayer inductor according to the present invention, wherein FIG.
(B) is a schematic cross-sectional view of the manufactured laminated inductor.

FIG. 4 is an explanatory view for manufacturing a fourth embodiment of the multilayer inductor according to the present invention.

FIG. 5 is a perspective view showing a conventional laminated inductor.

FIG. 6 is a view showing a conventional laminated inductor, and FIG.
FIG. 2 is an explanatory view for explaining the manufacture, and FIG. 2B is a schematic cross-sectional view of the manufactured laminated inductor according to the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer inductor 2 Internal conductor 2a, 2b Conductor pattern 3, 4 Leader conductor 7 Magnetic flux

Claims (5)

(57) [Claims] 1. A laminated inductor in which a cylindrical internal conductor is formed by lamination, each end of the internal conductor serves as a lead conductor, and the pair of lead conductors are connected to both external terminals. At least the inner conductor has a plurality of layers having a ring-shaped conductor pattern, and a straight line connecting the ring-shaped conductor pattern.
A multilayer inductor, comprising: a plurality of layers each having a shape of a conductor pattern . 2. The multilayer inductor according to claim 1, wherein the linear conductor pattern has an I shape. 3. The multilayer inductor according to claim 1, wherein the linear conductor pattern has an = shape. 4. The multilayer inductor according to claim 1, wherein the linear conductor pattern has a positive shape. 5. The multilayer inductor according to claim 1, wherein the ring-shaped conductor pattern has a square shape.