JP2002043129A - Laminated inductance element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated inductance element, the inductance value of which can be improved in frequency characteristic by suppressing the variation of the inductance value, in a region in which the inductance value decreases as the frequency becomes higher, and in addition, the Q-value of which can also be increased. SOLUTION: A coil 11, composed of spirally connected conductor patterns, is provided in a rectangular dielectric chip 10, by alternately laminating the conductor patterns and electrically insulating layers upon another. The coil 11 has spirally connected cavities 15 which are filled with a nonconductive material 16 in the inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductance element, and more particularly, to an improvement in a structure of a coil portion provided in a chip.

[0002]

2. Description of the Related Art As shown in FIG. 1, in a laminated inductance element, a conductor pattern and an electric insulator layer are alternately formed by printing and laminated sequentially, so that a conductor pattern is spirally formed inside a rectangular chip 1. A coil 2 connected in a shape is provided.

A conductor pattern having a desired thickness is formed by repeating a process of printing a silver paste in a predetermined pattern a plurality of times. Therefore, the thickness is controlled by changing the number of times of printing. As shown in FIG. 2, the cross section of the conductor pattern 3 forming the coil 2 is rectangular and the inside is dense.

[0004]

However, the above-mentioned conventional laminated inductance element has the following problems. That is, the inductance value (L value) of the multilayer inductance element has poor frequency characteristics. That is, as the frequency increases, the inductance value decreases, and when the frequency becomes higher than a certain frequency, the inductance value sharply increases. Then, there is a problem that the amount of decrease in the inductance value is large and the amount of change in the inductance value within a predetermined frequency range is large. There is also a problem that the Q value is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-described problems and to reduce the amount of change in the inductance value in a region where the inductance value decreases as the frequency increases. An object of the present invention is to provide a multilayer inductance element which can be suppressed, has a good frequency characteristic of an inductance value, and can increase a Q value.

[0006]

Means for Solving the Problems In order to achieve the above object, a laminated inductance element according to the present invention comprises a conductor pattern and an electrical insulator layer laminated in an appropriate order to form a laminated chip inside a rectangular chip. It is assumed that the laminated inductance element is configured so as to provide a coil in which the conductor pattern is spirally connected. And it comprised so that a cavity might be provided inside the said coil. Preferably, the cavity is configured to be continuous according to the spiral of the coil.

[0007] The coil is pulled out to the outside.
For example, it can be realized by positioning the tips of the extraction electrodes provided at both ends of the coil on the side surface of the chip, and conducting the external electrodes formed on the side surface to the extraction electrodes. Of course, other structures may be used.

According to the present invention, although the inductance value in a relatively low frequency band is lower than that of a conventional laminated inductance element having a hollow coil,
An amount of decrease in the inductance value when the frequency is increased is suppressed, and as a result, an element having a good frequency characteristic with a small variation width of the inductance value in a wide frequency range is obtained. Further, the Q value also increases. This can be estimated for the following reasons.

[0009] As is well known, the inductance value is determined by the number of magnetic fluxes linking the coil. In the high-frequency region, an eddy current occurs in the conductor, and the current flow in the conductor changes according to the frequency.
The inductance value also fluctuates. Therefore, by providing a cavity (non-conductive material) in the coil (conductor) in advance, even if the frequency changes, the current distribution in the conductor hardly fluctuates, thereby stabilizing the L value. That is, it is considered that the frequency characteristics are improved.

[0010] The Q value is proportional to L / R. Here, L is an inductance value, and R is a value obtained by adding the respective resistance values of the DC resistance component and the AC resistance component. If the external dimensions are the same, the provision of the cavity reduces the cross-sectional area of the conductor portion, and the DC resistance component becomes larger than that of the conventional one. At that point, the Q value will decrease. However, in the high frequency region, providing the cavity reduces the AC resistance component, and as a result, the Q value in the high frequency region is improved.

On the other hand, the cavity may be left as a space without a special member inserted therein, or the cavity may be filled with a non-conductive material. Considering the manufacturing process, it is preferable to arrange the non-conductive material in the cavity. When the non-conductive material is the same as the constituent material of the electric insulator layer, the manufacturing process is further facilitated.

[0012]

3 and 4 show a main part of a preferred embodiment of a laminated inductance element according to the present invention. In this embodiment, the basic configuration is the same as the conventional one. That is, the coil 11 superposed in the laminating direction is formed in the dielectric chip 10 formed by laminating the electric insulating layers (dielectric ceramic sheets).

The dielectric chip 10 is formed in a rectangular shape, and has external electrodes 12 connected to side surfaces 10a at both ends in the longitudinal direction and a part of each surface adjacent to the side surface 10a.
Are formed. Then, the extraction electrodes 13 formed continuously at both ends of the coil 11 are formed so as to extend so as to reach the side surface 10a, whereby the extraction electrodes 13 and the external electrodes 1 are formed.
2 is made conductive.

In this embodiment, the interior of the coil 11 is formed in the cavity 15 as shown in FIG. That is, by appropriately forming the conductor pattern, a hollow cylindrical conductor having a rectangular cross section is formed, and the cylindrical conductor is spirally arranged. This cavity 15 is formed throughout the coil and is continuous inside.

Further, the hollow cavity 15 may be filled with nothing or a non-conductive material 16 may be filled. As a specific material for filling, for example, the same material (alumina) as the electric insulating layer is preferably used in the manufacturing process, but may be formed of a material different from the electric insulating layer.

In order to manufacture the conductor pattern of this embodiment, for example, as shown in FIG. 5A, a conductor paste is formed on a non-conductive material (electric insulator layer) using a mask of a predetermined pattern. (Silver paste) is printed to form a conductor pattern (coil). That is, the first time the width w of the coil
Conductor pattern 11 having a predetermined planar shape having
a, and the second time, the second conductor pattern 11b is printed so as to overlap the first conductor pattern 11a. At this time, no conductive paste (silver paste) is formed on the center line, that is, on the cavity 15. Next, in the third printing process, a non-conductive material 16 such as alumina is applied to the cavity 15. Then, in the fourth printing process, the third conductive pattern 11b and the third conductive
The conductive pattern 11c is formed.

Thus, a cylindrical conductor having a rectangular cross section is formed by the first to third conductor patterns 11a to 11c. When the binder is filled in place of the non-conductive material 16, the binder evaporates at the time of the subsequent baking process, so that the interior of the cavity 15 can be made a space.

As shown in FIG. 5B, in the case of a conventional type having no cavity, the first type having the same shape is used.
Since the third to third conductor patterns 3a to 3c are laminated three times, the number of printing steps is increased by one in the present embodiment as compared with the conventional type, so that there is not much problem.

Next, in order to demonstrate the effect of the present invention, the following simulation was performed. First, as dimensions and shapes of the multilayer inductance element, FIGS.
As shown in FIG. 5, the width of the dielectric chip 10 is X, the depth is Y, the height is Z, the width of the built-in coil 11 is w, and the thickness is t. When the cavity 15 is provided in the coil 11, the width and the thickness are each set to 1/3 of the coil. And the specific chip size is
X = 1000 μm, Y = 500 μm, Z = 500 μm, and the conductor width w was 60 μm.

Further, assuming that the distances of the coil 11 from the outer periphery of the dielectric chip 10 are a, b, c, and d, respectively, a = 550 μm, b = 165 μm, and c = 190 μm
m, d = 95 μm. The above-mentioned values are common to each laminated inductance element. Then, when the number of turns, the thickness t of the conductor forming the coil, the distance s between the upper and lower conductors, and the distance e from the chip surface to the conductor are changed as shown in FIG. (Inductance value, Q value), and the results are shown in FIG.

Then, as shown in FIGS. 8 and 9, regardless of the number of turns, providing a cavity makes it possible to reduce the variation width of the inductance value with respect to a change in frequency.
The frequency characteristics are improved. Further, as shown in FIGS. 10 and 11, it was confirmed that the Q value was higher when the cavity was provided, regardless of the number of turns.

[0022]

As described above, in the multilayer inductance element according to the present invention, since the coil is formed by the conductor having a cavity inside, the fluctuation of the current distribution with the increase in the frequency is reduced, and the inductance value is reduced. , The amount of change in the inductance value can be suppressed, and the frequency characteristic of the inductance value is improved. In addition, the provision of the cavity reduces the AC resistance component in the high frequency region, so that the Q value can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional example.

FIG. 2 is a diagram showing a conventional example.

FIG. 3 is a perspective view showing a preferred embodiment of a multilayer inductance element according to the present invention.

FIG. 4 is a cross-sectional view showing a preferred embodiment of the multilayer inductance element according to the present invention.

FIG. 5 is a diagram showing a manufacturing process of the coil.

FIG. 6 is a diagram illustrating dimensions and shapes of elements used in a simulation.

FIG. 7 is a diagram showing specific values of parameters.

FIG. 8 is a graph showing an example of a frequency characteristic (inductance value).

FIG. 9 is a graph showing an example of a frequency characteristic (inductance value).

FIG. 10 is a graph showing an example of a frequency characteristic (Q value).

FIG. 11 is a graph showing an example of a frequency characteristic (Q value).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dielectric chip 10a Side surface 11 Coil 11a-11c 1st-3rd conductor pattern 12 External electrode 13 Leader electrode 15 Cavity 16 Non-conductive material

Claims (4)

[Claims] 1. A laminated inductance element in which a conductor pattern and an electrical insulator layer are laminated in an appropriate order to provide a coil in which the conductor pattern is spirally connected inside a rectangular chip. A laminated inductance element, wherein a cavity is provided inside the coil. 2. The multilayer inductance element according to claim 1, wherein the cavity is continuous according to a spiral of the coil. 3. The multilayer inductance element according to claim 1, wherein said cavity is filled with a non-conductive material. 4. The multilayer inductance element according to claim 3, wherein the non-conductive material is the same as a constituent material of the electric insulator layer.