JPS6328008A - Chip inductor - Google Patents

Abstract

PURPOSE:To reduce the size of a coil blank by providing a spiral conductor on an insulator plate to obtain an inductance. CONSTITUTION:A spiral conductor 3 is formed on the main surface of an insulator plate 2, and both ends of the conductor 3 are electrically connected to electrodes 4a, 4b formed at both ends of the plate 2. A coil blank 1 is composed of the plate 2, the conductor 3 and the electrodes 4a, 4b, one ends of metal plate terminals 5a, 5b are electrically connected to the electrodes 4a, 4b of the blank 1, and the other ends of the terminals 5a, 5b are bent along the surface of a resin sheath 6 as an external electric terminal. When magnetic ceramics are used as the plate 2, the inductance values of the conductors 3 of the same shape can be increased. Thermosetting resins are preferably used as the sheath 6. When epoxy resin of them is used, the bondability of the sheath with the terminals 5a, 5b is improved to provide high reliability.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a radio receiver and a television receiver.

This invention relates to a chip inductor that can be surface-mounted for use in general electronic equipment such as video tape recorders.

BACKGROUND OF THE INVENTION In recent years, electronic devices have become increasingly smaller and more densely packaged, and electronic components have also shifted from leaded to leadless chip components to even smaller chip components.

In the field of coils, chip inductors have been commercialized that are roughly divided into three types: wire-wound and laminated types, and bare wire-wound types and resin-molded types.

Each of these three types of chip inductors has unique features, and they are used to take advantage of those features. Among them, the resin molded type has excellent performance and reliability, including when mounted on a board. Due to its height, it has become the mainstream chip inductor.

FIG. 3 shows a semi-transparent perspective view of a conventional resin molded chip inductor. 2 in the same figure, 12 is a drum-shaped core, and a copper wire 13 is wound around the winding portion of the core, and a coil element 1
1 is formed. Lead portions (not shown) of the coil element 11 are electrically connected to metal plate terminals 142L and 14b, respectively.

15 is a coil element 11 and a metal plate terminal 14a.

This is an exterior resin that covers a part of 14b, and generally an epoxy resin is used.

A conventional chip inductor having a configuration that meets or exceeds the problems to be solved by the present invention has the feature that it is resistant to thermal stress during mounting because it has an exterior resin 15 that has high heat resistance and a large heat insulating effect. On the other hand, since a drum-shaped core 12 made of ferrite with a relatively complicated shape is used as the core of the coil element 11,
Due to limitations in machining, there is a limit to miniaturization of the chip inductor.

Furthermore, in a small inductance region, the number of turns of the copper wire 13 is reduced, resulting in a drawback that variations in characteristics such as the inductance IQI self-resonant frequency become large.

Means for Solving the Problems In order to solve the above problems, the chip inductor of the present invention is provided with a spiral conductor on at least one main surface of the insulator plate, and both ends of the conductor are connected to the insulator plate. Each is electrically connected to the electrodes provided at both ends to form a coil body,
A metal plate terminal is electrically connected to each of the electrodes, a part of the coil body and the metal plate terminal is coated with resin to provide a resin sheath, and the metal plate terminal is bent along the resin sheath. It is configured as an external terminal.

Function: As described above, by providing a spiral conductor on an insulator plate to obtain inductance, the coil body can be made smaller. The effect is particularly noticeable in the thickness direction. Furthermore, since the dimensions of the spiral conductor can be determined almost mechanically, variations in characteristics are extremely small.

Example The present invention will be described in detail below based on examples thereof.

FIG. 1 is a transparent perspective view showing an embodiment of the present invention. In the figure, 2 is an insulator plate, and a spiral conductor 3 is provided on its main surface. Both ends of the spiral conductor 3 are electrically connected to electrodes 4a and 4b provided at both ends of the insulator plate 2, respectively.

Above insulator plate 2. Spiral conductor 3. electrode jl.

4b constitutes the coil body 1. sa and sb are metal plate terminals, one end of which is electrically connected to the electrodes 4&, 4b of the coil body 1, respectively.

The other ends of the metal plate terminals 6a, 5b are bent along the surface of the resin sheath 6 to serve as external electrical terminals.

As the insulator plate 2, insulating ceramics such as alumina can be used. In this case, mechanical.

Because it is extremely thermally stable, variations in properties can be suppressed.

In addition, magnetic ceramics (ferrite) can be used as the insulator plate 2.
You can also use When using magnetic ceramics,
There is an advantage that the inductance value can be increased in the spiral conductor 3 having the same shape.

It is preferable to use a thermosetting resin as the resin sheath 6, and among these, if an epoxy resin is used, the metal plate terminal 5
Adhesion with 1L and 5b is improved and reliability is high.

Note that by mixing magnetic ceramic powder into this epoxy resin, a large inductance can be realized and a magnetic shielding effect can be exhibited.

FIG. 2 shows an example of the coil element shown in FIG. 1. One end of the spiral conductor 3 provided on one main surface of the insulating plate 2 is electrically connected to an electrode 4a. The other end is electrically connected to the electrode 4b through the through hole 7 and the other main surface.

The spiral conductor 3 and the electrodes 4L, 4b can be provided by printing and baking Ag-Pd. It can also be provided by copper plating or etching.

In this embodiment, the spiral conductor 3 is provided only on one main surface, but a similar spiral conductor may also be provided on the other main surface and connected in series through the through hole 7.

Effects of the Invention As described above, the chip inductor of the present invention can realize a more compact shape by configuring the coil body by providing a spiral conductor on an insulator plate. In particular, the dimension in the thickness direction can be significantly reduced.

Further, since the dimensions of the spiral conductor can be determined almost mechanically by the dimensions of a mask used in printing, etc., variations in characteristics can be greatly reduced.

[Brief explanation of drawings]

FIG. 1 is a transparent perspective view showing an embodiment of the chip inductor of the present invention, FIG. 2 is a plan view showing an example of the coil body of the present invention, and FIG. 3 is a transparent perspective view showing a conventional chip inductor. It is a diagram. 1... Coil body, 2... Insulator plate,
3...Spiral conductor, 41L, 4b...
...Electrode, 5a, sb...Metal plate terminal,
6...Resin exterior.

Claims (4)

[Claims] (1) A spiral conductor is provided on at least one main surface of the insulator plate, and both ends of the conductor are electrically connected to electrodes provided at both ends of the insulator plate to form a coil element, A metal plate terminal is electrically connected to each of the electrodes, a part of the coil body and the metal plate terminal is coated with resin to provide a resin sheath, and the metal plate terminal is bent along the resin sheath. Chip inductor with external terminals. (2) The chip inductor according to claim 1, wherein the insulator plate is made of insulating ceramic. (3) The chip inductor according to claim 1, wherein the insulator plate is made of magnetic ceramics. (4) The chip inductor according to claim 1, wherein the chip inductor is provided with a resin exterior made of a resin mixed with magnetic ceramic powder.