JPH0729737A - Chip inductor - Google Patents

Abstract

PURPOSE:To obtain a chip inductor of a structure wherein a stray capacitance, which is generated between input/output electrodes, is small. CONSTITUTION:Input/output electrodes 5 and 6 having a U-shaped sectional form are respectively provided on both end surfaces 4a and 4b of a laminated material 4, which is constituted of a magnetic material 1 provided with a built-in coil conductor and low-dielectric constant members 3 provided on the upper and lower surfaces of this magnetic material 1. As the material for the members 3, a cordierite, a steatite, high alumina, a low-dielectric constant magnetic material or the like is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip inductor used for constructing various electronic circuits.

[0002]

2. Description of the Related Art As shown in FIG. 6, one type of chip inductor has been proposed in which input / output electrodes 33 and 34 are provided at both ends of a laminate 32 in which a coil conductor and an insulator are stacked. There is. The input / output electrodes 33, 34 are respectively formed on the end faces 32a, 32b of the laminated body 32, and the extending portions thereof have an upper surface 32c, a lower surface 32d and both side surfaces 32e, 32.
It is located at f. In general, the material of the insulator is selected to satisfy the coil characteristics such as inductance and goodness (Q). Therefore, when an insulating material having a relatively large dielectric constant is used, the input / output electrode 3
Stray capacitance was generated on the surface portion of the chip inductor between 3 and 34, and the frequency characteristics of the chip inductor in the high frequency band were deteriorated.

Therefore, an object of the present invention is to provide a chip inductor having a small stray capacitance generated between the input and output electrodes.

[0004]

In order to solve the above problems, in the chip inductor according to the present invention, a low dielectric constant member is provided on the surface of a laminated body in which coil conductors and insulators are alternately stacked, External electrodes electrically connected to the coil conductors are provided at both ends of the laminate. As the material of the low dielectric constant member, cordierite, steatite, high alumina, or a magnetic material having a low dielectric constant is used.

In the above structure, since the low dielectric constant member is provided on the surface of the laminated body, the stray capacitance generated on the surface portion of the chip inductor between the input and output electrodes is reduced.

[0006]

Embodiments of the chip inductor according to the present invention will be described below with reference to the accompanying drawings. [First Embodiment, FIGS. 1 to 4] As shown in FIG. 1, a chip coil has a magnetic sheet 1 having a linear coil conductor 2 on its surface, a magnetic sheet 1 having no conductor, and a low dielectric constant material. It is composed of the seat 3. The low dielectric constant material sheet 3 is made of a material having a lower dielectric constant than the magnetic material sheet 1. Specifically, cordierite, steatite, high alumina, or a magnetic material having a low dielectric constant is used.

Both ends of the coil conductor 2 are attached to the magnetic sheet 1.
It is exposed on the left and right edges. The coil conductor 2 is formed by applying a conductive paste to the surface of the magnetic material sheet 1 by means of printing or the like and drying it. As the conductive paste,
A metal powder such as Ag or Ag-Pd kneaded with a binder and a solvent is used. Magnetic sheet 1 without conductor
Are stacked with the magnetic sheet 1 having the coil conductor 2 provided on the surface therebetween. Further, after stacking the low dielectric constant material sheets 3 on the upper and lower sides thereof, they are pressure-bonded and baked to form a laminated body 4.

As shown in FIGS. 2 and 3, this laminated body 4
Input / output electrodes 5 and 6 are formed on both end surfaces 4a and 4b of the coil while being electrically connected to the coil conductor 2, respectively. The input / output electrodes 5 and 6 are U-shaped in cross section, and the extending portions thereof are arranged on the upper surface 4c and the lower surface 4d of the laminated body 4, but not on both side surfaces 4e and 4f. Both sides 4e, 4
Since a low dielectric constant member is not provided on the surface of f, if the extending portions of the input / output electrodes 5 and 6 are arranged on both side surfaces, a stray capacitance is generated between the input / output electrodes 5 and 6 though it is small. Because it does.

In the chip inductor thus obtained, stray capacitance is generated between the input / output electrodes 5 and 6 at the portion where the distance between the input / output electrodes 5 and 6 is narrow, that is, at the upper and lower surfaces of the chip inductor. Since the low dielectric constant sheet 3 is arranged on the lower surface, the stray capacitance generated is reduced. Therefore, when this chip inductor is used as, for example, a noise filter, the solid line 10 in FIG.
As can be seen from the impedance frequency characteristic indicated by, the impedance in the high frequency band becomes larger than that of the conventional chip inductor (see the dotted line 11) due to the reduction of the stray capacitance, and the noise removal capability can be improved.

[Second Embodiment, FIG. 5] As shown in FIG.
The chip inductor of the second embodiment is a linear coil conductor 2
Input / output electrodes 25 and 26 are provided on both end surfaces 23a and 23b of a laminated body 23 composed of 0, the magnetic material sheet 21 and the low dielectric constant material sheet 22. Input / output electrodes 25, 2
6 has an L-shaped cross section, and the extending portion thereof is a laminated body 23.
Is provided on the lower surface 23d, and is not provided on the upper surface 23c and both side surfaces. The chip inductor thus obtained has the same operation as the chip inductor of the first embodiment,
Produce an effect.

[Other Embodiments] The chip inductor according to the present invention is not limited to the above embodiments, but can be variously modified within the scope of the gist thereof. A pair of capacitor electrodes may be arranged inside the chip inductor of the above embodiment to form an LC composite component.

An insulating sheet such as a dielectric sheet may be used in place of the magnetic sheet used in the chip inductor of the above embodiment. The coil conductor is not limited to the linear one. That is, the pattern shape, the number, and the arrangement position are arbitrary as long as they can generate an inductance, such as a zigzag shape, a multilayer structure through via holes, and a spiral shape.

Further, in the above embodiment, the insulating sheets are stacked and then integrally fired, but the present invention is not necessarily limited to this. For example, the chip inductor may be manufactured by the manufacturing method described below. A paste-like low dielectric constant material is applied by a means such as printing and dried to form a low dielectric constant material film, and then a paste-like insulating material is applied to the surface of the low dielectric constant material film and dried to produce an insulating material. Form a film. Next, a paste-shaped conductor material is applied and dried to form an arbitrary inner conductor. In this manner, the chip inductor having a laminated structure is obtained by sequentially applying the layers.

[0014]

As is apparent from the above description, according to the present invention, since the low dielectric constant member is provided on the surface of the chip inductor, the stray capacitance generated on the surface portion of the chip inductor between the input and output electrodes can be reduced. can do. As a result,
When this chip inductor is used as a noise filter, it is possible to improve the noise removal capability in the high frequency band.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a chip inductor according to the present invention.

FIG. 2 is a perspective view showing the external appearance of the chip inductor shown in FIG.

3 is a cross-sectional view of the chip inductor shown in FIG.

FIG. 4 is a graph showing impedance frequency characteristics of the chip inductor shown in FIG.

FIG. 5 is a sectional view showing a second embodiment of the chip inductor according to the present invention.

FIG. 6 is a perspective view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic body sheet 2 ... Coil conductor 3 ... Low dielectric constant material sheet 4 ... Laminated body 5,6 ... Input / output electrode 20 ... Coil conductor 21 ... Magnetic body sheet 22 ... Low dielectric constant material sheet 23 ... Laminated body 25, 26 ... I / O electrodes

Claims (1)

[Claims] 1. A low dielectric constant member is provided on the surface of a laminate in which coil conductors and insulators are alternately stacked, and external electrodes electrically connected to the coil conductor are provided at both ends of the laminate. Is a chip inductor.