JPS6012272Y2 - ceramic circuit board capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor incorporated in a ceramic circuit board.

Capacitors incorporated into ceramic circuit boards include those that are attached to the circuit board with a conductive adhesive such as solder, and those that are formed on the circuit board using thick film processing technology.

However, such conventional devices have a number of drawbacks.

That is, the former has drawbacks such as being a protrusion on the circuit board, increasing the number of parts, requiring positioning, and low reliability due to the large number of connection points.

Furthermore, the latter has drawbacks such as an increased occupation area, a lower degree of integration on the circuit board, and difficulty in obtaining good high frequency characteristics.

This invention was made to eliminate the above-mentioned drawbacks.
A ceramic circuit board capacitor in which a capacitor is built into a through hole of a ceramic substrate, in which at least one electrode forming the capacitor is printed and formed on the inner wall of the through hole of a ceramic substrate, and the capacitor is fixed. The present invention aims to provide a capacitor and a trimmer capacitor in which one electrode forming the capacitor is made of a metal piece and is slidable on a dielectric.

Examples thereof will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a pair of capacitor electrodes 1 and 3 are baked on the inner surface of a through hole 4 provided in a circuit board 5 with a dielectric layer 2 in between, using molybdenum, tungsten, etc. as the main component. Formed of a conductive metal layer, these capacitor electrodes extend for connection, but there are also ceramic circuit board capacitors that are taken out together on one side of the circuit board 5, as shown in FIG. As shown in the figure, there are also separate ceramic circuit board capacitors taken out on each side of the circuit board 5.

In the present invention, in order to make such a ceramic circuit board capacitor into a variable capacitance type (trimmer) capacitor, the capacitor electrode inside the through hole, that is, on the side that is separated by the dielectric layer 2 from the circuit board 5, is baked into a conductive layer as described above. sexual metal layer 3
Instead, a metal piece such as a threaded metal rod 3' or a metal tube is used as a capacitor electrode.

The screw 3'a is screwed into and supported by a nut 8 and is electrically connected, and the nut 8 is connected to a conductive metal layer 6 formed on the circuit board 5 with a conductive adhesive 7.

In this circuit board capacitor, the capacitance of the capacitor can be changed by moving the screw 3'a up and down, similar to the conventional variable capacitor.

In the trimmer capacitor of this invention, as in the case of the fixed capacitor described above, the connection circuit of the capacitor electrode is connected to the third
It is possible to take out the circuit board on one side, as shown in the figure, or on both sides of the circuit board, as shown in FIG.

Next, in the example shown in FIG. 5, the capacitor electrode 1 on the circuit board side is baked onto the circuit board 5 and its through hole 4, and the dielectric layer 2 is further formed on it, as in the case of the trimmer capacitor described above. It is also possible to use a structure in which the hole inside the dielectric layer 2 is filled with molten metal and solidified to form the other capacitor electrode 9.

Furthermore, as shown in Fig. 6, capacitor electrodes 1 and 3 are formed on the through-hole surface of the circuit board using a baked conductive metal layer divided into multiple parts, and a dielectric material is filled in the through-hole to form a capacitor. You may.

The electrode in the through hole is usually divided into two parts, and a capacitor is formed by these two capacitor electrodes 1.3 and the dielectric material 2 filled between them. When used, air becomes the dielectric, and when used in a vacuum, the vacuum becomes the dielectric.

Furthermore, a capacitor filled with a solid material having a high dielectric constant can have a larger capacitance.

Furthermore, for special applications, the electrode can be divided into three or more parts.

Capacitors formed in this way can be made smaller by using the same dielectric material, the number of parts can be reduced, positioning is easy for variable capacitors, and the circuit board The protrusion on the top can be made smaller, the built-in circuit board occupies less space and increases the degree of integration, cylindrical through-holes provide better high-frequency characteristics, and the smaller number of contacts improves reliability. , which eliminates the drawbacks of conventional capacitors, and also contributes to the simplification of the manufacturing process because the capacitor electrodes can be formed using the same conductive material used for the wiring on the circuit board. As such, its practical value is extremely great.

In the present invention, the effects of printing at least one electrode on the inner wall of the through hole of the substrate and forming a conductive metal layer by baking are listed below.

(1) Since one electrode can be printed in a cylindrical shape on the inner wall of the substrate through-hole, the capacitor electrode can be made larger relative to the area occupied by the ceramic substrate, so the capacitor can be made smaller and the packaging density can be improved.

(2) Since the electrodes and dielectric of the capacitor can be formed using the same printing method, the manufacturing process can be simplified and mass production can be performed.

(3) Since the dielectric material can be made thinner by printing, the capacitance of the capacitor can be increased.

(4) The through-hole in which the capacitor is formed can also be used for assembling electronic components with leads, thereby improving the packaging density.

(5) In Examples 3 and 4, the capacitance of the capacitor can be changed reversibly.

(6) Two capacitors on the same side of the ceramic circuit board.
Since two electrodes can be formed, two completely different circuits can be formed on both the front and back sides of a single substrate.

[Brief explanation of the drawing]

Figures 1 and 2 are cutaway front views showing an embodiment in which the capacitor of the present invention is a fixed capacitor, and Figures 3 and 4 show an embodiment in which the capacitor of the present invention is a trimmer capacitor. A partially cutaway front view, FIG. 5 is an explanatory diagram showing an embodiment in which the electrode is filled with metal, and FIG. 6 is an explanatory diagram of an embodiment in which split electrodes are used. 1...Capacitor electrode, 2...Dielectric layer, 3...Capacitor electrode, 3'...
Threaded metal rod, 3'a... Screw, 4...
・Through hole, 5...Circuit board, 6...
... Conductive metal layer, 7... Conductive adhesive, 8.
...nut, 9...capacitor electrode.

Claims (1)

[Claims for Utility Model Registration] In a ceramic substrate capacitor in which a dielectric material interposed between a pair of electrodes is disposed in a through-hole of a ceramic substrate and a capacitor is built-in, at least one of the electrodes forming the capacitor is A ceramic circuit board capacitor in which electrodes are printed on the inner wall of a through-hole in a ceramic substrate and baked to form a conductive metal layer. 2. The ceramic circuit board capacitor according to claim 1, wherein one electrode forming the capacitor is made of a metal piece and is slidable on the dielectric.