JPH0630324B2 - LC composite parts - Google Patents

Description

The present invention relates to an LC composite component, and more particularly to an LC composite component such as an LC filter having a distributed constant type structure.

[Prior art]

An example of a distributed constant type LC filter is, for example, Japanese Patent Publication No.
No. 6-25817.

This distributed constant type LC filter is formed into a cylindrical shape as a whole for the purpose of being inserted into a connector pin and used. Such a distributed constant type has a good frequency characteristic, but has a cylindrical shape, so that it cannot be mounted on a substrate.

On the other hand, an example of a chip type LC filter that can be mounted on a substrate is disclosed in, for example, Japanese Utility Model Laid-Open No. 62-44522. However, this chip type LC filter is of the lumped constant type.

[Problems to be solved by the invention]

Although the chip type filter can be easily mounted on the substrate, it has a problem that the frequency characteristic is not so good as the distributed constant type because it is a lumped constant type.

Therefore, a main object of the present invention is to provide an LC composite component which is a distributed constant type and can be mounted on a substrate.

[Means for solving problems]

This invention is a laminate (12) of a dielectric layer (18a ~ 18d) and a magnetic layer (24), formed at the interface between the dielectric layer and the magnetic layer over the entire length of the laminate. , The first end (20b) of which the longitudinal end (20b) is exposed at the longitudinal end face of the laminate (2
0), a second conductor (22) which is formed in the laminate and faces the first conductor with the dielectric layer sandwiched between the first conductor and the widthwise end portion (22b) of which is exposed at the widthwise end face of the laminate. A first external electrode (14) formed on both lengthwise end faces of the body and connected to the exposed first conductor, and a second external electrode formed on the widthwise end face of the laminate. A second external electrode (16) connected to the conductor is provided, the first conductor forms an inductance between the first external electrodes over the entire length of the laminate, and the first conductor and the second conductor. Is an LC composite component that forms a capacitance connected to a second external electrode by a portion facing with.

[Action]

An inductance is formed between the first external electrodes at both ends by the interaction between the laminated body, the magnetic layer, and the first conductor.
By the dielectric layer interposed between the first conductor and the second conductor,
A capacitance is formed. For example, if the first external electrode is inserted in the signal path and the second external electrode is grounded, a distributed constant type LC filter can be obtained.

〔The invention's effect〕

According to the present invention, since it is formed in a chip type, it is easier to mount on a substrate as compared with the conventional distributed constant type LC filter. Moreover, since it is a distributed constant type, it has good frequency characteristics.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

〔Example〕

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.
The figure is a completed external perspective view.

With reference to FIG. 2, the LC composite component 10 includes a laminated body 12, external electrodes 14 are formed on both end surfaces of the laminated body 12, and an external electrode 16 is formed on a substantially central portion of the end surface in the width direction. It

First, as shown in FIG. 1, 4 cut into the same size
The dielectric sheets 18a to 18d are prepared. And
The strip line 20 is formed on the upper surface of the dielectric sheet 18a by, for example, screen printing. The strip line 20 has a straight line portion 2 formed in the center of the sheet.
0a and the terminal portion 20b, and is formed as an I-type as a whole. The terminal portions 20b are the dielectric sheets 18a, respectively.
Exposed from the longitudinal edge of the.

An internal electrode 22 is formed on the upper surface of the dielectric sheet 18c at approximately the center by screen printing, for example. The internal electrode 22 has a substantially cruciform shape by an electrode portion 22a that is completely hidden when the dielectric sheet 18b is superposed thereon and terminal portions 22b formed by extending from both sides in the width direction of the electrode portion 22a. Exhibit a shape. Terminal part 22
b is exposed from the widthwise edge of the dielectric sheet 18c. The internal electrode 22 does not necessarily have to be formed in a substantially cross shape, and may have another shape as long as it has an area facing the strip line 20 and has the terminal portion 22b.

These dielectric sheets 18a to 18d are superposed, and a plurality of ferrite sheets 24 are superposed on and below the dielectric sheets 18a to 18d.

On the upper surface of the uppermost ferrite sheet 24a forming the lower ferrite sheet block, the dielectric sheet 1
Similarly to 8a, the strip line 20 having the straight line portion 20a and the terminal portion 20b is formed.

The upper and lower ferrite sheet blocks and the dielectric sheet blocks sandwiched between the upper and lower layers are integrally laminated by, for example, thermocompression bonding and then fired to form a laminated body 12 shown in FIG.
Becomes

As shown in FIG. 3, the cross section of the laminated body 12 has a dielectric layer 18 'formed of dielectric sheets 18a to 18d.
And a magnetic layer 24 'formed of a ferrite sheet block. An internal electrode 22 is formed inside the dielectric layer 18 ', and strip lines 20 are formed at the interfaces between the dielectric layer 18' and the magnetic layer 24 '. The dielectric layer 18 'and the magnetic layer 2
The strip line 20 formed at the interface with 4'may be formed on the dielectric sheet forming the interface or on the magnetic sheet.

The strip line 2 is formed on both end faces of the laminate 12 in the length direction.
The external electrode 14 is formed so as to be electrically connected to the zero terminal portion 20b. Then, the distributed inductance L shown in FIG. 4 is formed between the external electrodes 14 due to the interaction between the strip line 20 and the magnetic layer 24 '. In this way, when the distributed inductance L is formed by the strip lines 20, in order to form a sufficient magnetic flux, the dielectric layer 1 between the strip lines 20 is formed.
The thickness of 8'is as thin as possible.

In addition, the external electrodes 16 are formed at substantially central portions of both end surfaces in the width direction of the laminated body 12 so as to be electrically connected to the terminal portions 22b of the internal electrodes 22 in the laminated body 12. In this way, the capacitance C shown in FIG. 4 is formed. In this way, in order to form the capacitance C between the strip line 20 and the internal electrode 22, it is preferable that the interposed dielectric sheets 18a to 18d be as thin as possible. In the embodiment, it is several tens to several hundreds μm.

The insertion loss with respect to frequency of the lumped constant type LC composite component is theoretically 40 dB / decade for the L type and 60 for the π type.
In contrast to the dB / decade, the distributed constant type LC composite component 10 of this embodiment has an insertion loss of 80 dB / de.
It has excellent characteristics with cade.

FIG. 5 is an illustrative view showing another embodiment of the present invention. In this embodiment, the dielectric paste layer 26 is formed by printing a dielectric paste in order to thin the dielectric as described above. That is, the ferrite sheet 2
A strip line 20 having the same shape as that of the previous embodiment is formed on the lower surface of 4a, and the straight line portion 20a is formed substantially at the center of the straight line portion 20a of the strip line 20.
A dielectric paste layer 26 is formed from above by screen printing, for example. The strip line 20 and the dielectric paste layer 26 are similarly formed on the upper surface of the ferrite sheet 24b. Then, the internal electrode 22 is formed on the dielectric paste layer 26 to be the lower layer. Other parts are almost the same as the previous embodiment,
Detailed description is omitted.

The dielectric paste layer 26 may be formed so as to entirely cover the straight line portion 20a of the strip line 20, as shown by the broken line in FIG.

FIG. 6 is an illustrative view showing another embodiment of the present invention. In this embodiment, the dielectric is formed by the dielectric sheet 28 as in the previous embodiment of FIGS. 1 and 2. That is, the substantially cross-shaped dielectric sheets 28 are stacked on the strip lines 20. Then, in FIG. 6, the internal electrodes 22 are printed on the dielectric sheet 28 which is superposed on the ferrite sheet 24b.

7A and 7B are illustrative views showing still another embodiment of the present invention. In this embodiment, the dielectric layer (dielectric sheet or dielectric paste layer) 30 and the internal electrode 22 are formed narrow as a whole. Thereby, the eighth
A laminate 12 having the cross section shown in the drawing is obtained. In this embodiment, since the dielectric layer 30 and the internal electrodes 22 other than the central portion are narrow in width, the magnetic flux generated when a current flows through the strip line 20 exists around the strip line 20. As a result, the inductance L (FIG. 4) between the external electrodes 14 becomes large.

9 to 11 are cross-sectional views showing other embodiments of the present invention. In the embodiment shown in FIG. 9, the magnetic layer 24 'is formed only on the lower side as compared with the embodiment shown in FIG. In the embodiment shown in FIG. 10, a large number of strip lines 20, 20 'are formed by the magnetic layer 24'. In the embodiment shown in FIG. 11, the magnetic layers shown in FIG. 10 are arranged on the upper and lower sides of the dielectric layer.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention. FIG. 2 is a perspective view showing the completed appearance of the embodiment shown in FIG. FIG. 3 is a longitudinal sectional view of the embodiment shown in FIGS. 1 and 2. FIG. 4 is an equivalent circuit diagram of the embodiment shown in FIGS. FIG. 5 is an illustrative view showing another embodiment of the present invention. FIG. 6 is an illustrative view showing another embodiment of the present invention. FIGS. 7A and 7B are plan views showing a ferrite sheet used in still another embodiment of the present invention. FIG. 8 is a longitudinal sectional view showing the embodiment shown in FIGS. 7A and 7B. 9 to 11 are vertical sectional views showing other embodiments of the present invention. In the figure, 10 is an LC composite component, 12 is a laminate, and 1
4, 16 are external electrodes, 18 'is a dielectric layer, 20 is a strip line, 22 is an internal electrode, and 24' is a magnetic layer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ken Azumi 2-26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd. (56) References -83107 (JP, U)

Claims (1)

[Claims] 1. A laminate (12) of a dielectric layer (18a-18d) and a magnetic layer (24), at the interface between the dielectric layer and the magnetic layer, along the length of the laminate. Is formed over its lengthwise end (20b)
A first conductor (20) exposed on the end face in the longitudinal direction of the laminate, the first conductor (20) being formed in the laminate and sandwiching the dielectric layer
A second conductor (22) facing the conductor of the laminate and having its widthwise end portion (22b) exposed at the widthwise end face of the laminate, the second conductor (22) being formed at both lengthwise end faces of the laminate. A first external electrode (1
4), and a second external electrode (16) formed on the end face in the width direction of the laminate and connected to the exposed second conductor, and the first external conductor (16) is provided by the first conductor. An LC that forms an inductance between the external electrodes over the entire length of the stacked body, and forms a capacitance connected to the second external electrode by the facing portion of the first conductor and the second conductor. Composite parts.