JPS6158965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable capacitor whose capacitance can be adjusted.

When adjusting the capacitance of a capacitor in which an electrode, a dielectric material, and an electrode are laminated on a substrate, for example, the upper electrode is formed into a comb-teeth shape, and the roots of these teeth are cut to reduce the opposing area of the electrodes. Adjustments to reduce the capacitance of the capacitor are common.

In this case, if the capacity has been reduced too much, it is difficult to increase it, and fine adjustment is also difficult. Furthermore, expensive conductive pastes such as silver palladium are often used for the electrodes, and redundant electrodes must be formed, which increases costs.

An object of the present invention is to provide a variable capacitor whose capacitance can be easily adjusted and which can be manufactured at low cost. Hereinafter, one embodiment will be described based on the drawings.

The substrate 1 is made of an insulating material such as ceramic, and has wiring portions 2 and lead-out electrode portions 3 formed of a conductive paste such as silver palladium on its surface. Reference numeral 4 indicates a bonding point for the integrated circuit element. 5 is a variable capacitor.

Next, the variable capacitor 5 will be explained in detail. As shown in the third figure, the lower electrode 6 of the capacitor 5 is formed on the substrate 1 at the same time as the wiring section 2 and the lead-out bipolar section 3. As mentioned above, this is a method in which a conductive paste such as silver palladium is formed on a substrate by printing to a thickness of several tens of microns. The electrode 6 is the base 6
a, and a plurality of (three in the drawings) extending portions 6b, 6c, and 6d of different widths that protrude from this base. 6e is a drawer terminal portion. A dielectric material 7 shown in the fourth figure is laminated on this electrode 6.

This dielectric is made of alumina porcelain or the like, and is formed to have a thickness of approximately several tens of microns, depending on the capacity. Furthermore, an upper electrode 8 as shown in FIG. 5 is laminated on top of the dielectric 7 in correspondence with the base 6a. Like the electrode 6, this electrode 8 is also made of conductive paste formed to a thickness of several tens of microns. After three layers are laminated on the substrate 1, they are placed in a heating furnace and fired to form the variable capacitor 5.
In addition, 8a is a drawer terminal part, and 8b is a connection part.

The protrusions 6b, 6c, and 6d are for rough adjustment, respectively.
This is for medium adjustment and fine adjustment. Pull-out terminals 6e, 8
While measuring the capacitance between A and A, an additional electrode 9a is attached to the top of the protrusion 6b for rough adjustment so as to match the electrode 8, and the capacitance is roughly adjusted. In this case, since the protrusion 6b is wide, the area where the electrodes 6 and 8 face each other increases significantly by attaching the additional electrode 9a, and the capacitance changes greatly. Next, the additional electrode 9b is attached adjacently to the upper part of the protruding part 6c for medium adjustment, and finally the additional electrode 9c is attached to the upper part of the protruding part 6d for fine adjustment, thereby completing the adjustment of the capacitance. Note that instead of performing the coarse adjustment, medium adjustment, and fine adjustment three times as described above, the adjustment may be performed once or twice. Adjustment is extremely easy if a pencil is used as the material for the additional electrodes 9a, 9b, 9c. In this case, if too much pencil carbon is attached, it can be erased with an eraser. If the capacity is adjusted using a pencil, it is desirable to apply a protective coating on top of the pencil.

As described above, according to the present invention, since the lower electrode is provided with a plurality of protrusions having different widths, the capacitance can be adjusted over a wide range and fine adjustments can be made easily and accurately. Furthermore, since the amount of additional electrodes for capacitance adjustment can be kept to the minimum necessary, expensive conductive paste can be saved significantly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view, FIG. 2 is a front view of main parts showing an adjustment method, FIG. 3 is a front view of the lower electrode, and FIG. 4 is a front view of the dielectric. ,
FIG. 5 is a front view of the upper electrode. 1... Base, 6... Lower electrode, 7... Dielectric,
8... Upper electrode, 9a, 9b, 9c... Additional electrodes.

Claims (1)

[Scope of Claims] 1. A lower electrode formed on an insulating substrate and consisting of a base and a plurality of protrusions having different widths extending from the base; and a dielectric material formed on the lower electrode. an upper electrode formed on the dielectric corresponding to the base; and an additional capacitance adjustment electrode formed on the dielectric corresponding to the protrusion so as to be connected to the upper electrode. A variable capacitor composed of