JPH0685490B2 - Method for manufacturing piezoelectric ceramic resonator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a piezoelectric ceramic resonator that functions as a filter or an oscillator used in various electronic equipment such as communication equipment, video equipment, and audio equipment.

2. Description of the Related Art Piezoelectric ceramic resonators have various vibration modes depending on the frequency band used. That is, lengthwise vibration and spreading vibration are used from the LF band to the MF band, and thickness vertical vibration, thickness shear vibration, and thickness shear vibration from the HF band to the VHF band.
Surface acoustic wave vibration or the like is used. Since the frequency constant is constant depending on the material, the resonance frequency is determined by the size of the resonator. In addition, it is necessary to reduce the vibration other than the vibration to be used to the required degree.

FIG. 4 shows the configuration of a conventional piezoelectric ceramic resonator using longitudinal vibration and spreading vibration. In FIG. 4, 1 is a piezoelectric ceramic, and 2 and 3 are counter electrodes. Such a piezoelectric ceramic resonator is manufactured by obtaining a plate-shaped sintered body, providing opposite electrodes on both surfaces thereof, and polarizing and then dividing the piezoelectric ceramic resonator into individual piezoelectric ceramic resonators. Moreover, as a method for obtaining a plate-shaped sintered body, any one of the following three methods is performed. That is, a block-shaped sintered body is prepared and sliced into a plate shape. A plate-shaped molded body is obtained by sheet molding and is fired. It is a method in which a plate-shaped molded body is obtained by extrusion molding and is fired. A piezoelectric ceramic resonator using such longitudinal vibration or spreading vibration reduces unnecessary vertical vibration, so that the peripheral portion of the piezoelectric ceramic resonator is chamfered from the shape shown in FIG. 4 by using an abrasive or polishing paper. Was being done.

Problems to be Solved by the Invention In such a conventional manufacturing method, the number of steps of chamfering is increased, and a relatively coarse abrasive or polishing paper is used for efficient chamfering. Unnecessary spurious is likely to occur at the longitudinal vibration or the spreading vibration. Further, there is a drawback that chamfering is difficult to be performed uniformly, and variations occur between elements.

The present invention solves such a problem, and an object of the present invention is to provide a method of manufacturing a piezoelectric ceramic resonator which is excellent in mass productivity and can reduce unnecessary thickness vibration.

Means for Solving the Problems In order to solve the above problems, the present invention creates a plate-shaped molded body having a groove by extrusion molding and divides the molded body to divide one end or both ends of each piezoelectric ceramic resonator. The part has a thickness gradient.

By this method, by grading the thickness at one end or both ends of the piezoelectric ceramic resonator, the vibration dimension of the vertical vibration is not constant, and unnecessary vertical vibration can be reduced. Moreover, since the thickness of the piezoelectric ceramic resonator is inclined in the case of a continuous molded body, it is excellent in mass productivity, and does not have to be roughened on the end face unlike chamfering with a sintered body, and has excellent uniformity. There is.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, 4 parts by weight of methyl cellulose, 5 parts by weight of propylene glycol, and microcrystalline wax based on 100 parts by weight of a piezoelectric ceramic raw material having a composition of manganese dioxide added to a ternary system of lead titanate, lead zirconate, and lead magnesium niobate. 1 part by weight and 15 parts by weight of water were added, and the mixture was kneaded and kneaded by a usual method to obtain a raw material for extrusion molding. The extrusion molding machine 4 having an outlet having a sectional shape as shown in FIG.
As shown in the figure, a plate-shaped compact 6 having a groove 5 and a thickness of 0.6 mm and a width of 120 mm was extruded. Next, this continuous plate-shaped molded body 6 was dried in a drying zone, cut into about 50 mm and baked. Next, after firing, silver paste was screen-printed on both sides of the plate-shaped sintered body and baked.

Next, this was polarized and cut into individual piezoelectric ceramic resonators having the shape shown in FIG. In this way, the individual piezoelectric ceramic resonators 7 after cutting are formed by the grooves 5 during extrusion molding.
A thickness gradient 8 was formed at both ends of the. As a result, the thickness of the resonator is not uniform, and unnecessary vertical vibration can be reduced in the resonator of spreading vibration. In addition, as compared with the conventional chamfering with a sintered body, unnecessary spurious is less likely to occur at the spreading vibration. In addition, in FIG.
10 is a counter electrode.

In this embodiment, the thickness is inclined only on one side in the thickness direction, but it may be attached on both sides. Further, although the thickness is inclined at both ends, the same effect can be obtained by only one end. Furthermore, after firing, electrode attachment, and polarization, they were individually cut and divided. However, they may be divided individually when forming a molded body, and then fired, attached with electrodes, and polarized.

EFFECTS OF THE INVENTION As described above, according to the method of the present invention, it is possible to manufacture a piezoelectric ceramic resonator using longitudinal vibration or spread vibration in which unnecessary thickness vertical vibration is reduced by a method suitable for mass production. It is possible and practically extremely useful.

[Brief description of drawings]

1 to 3 are views for explaining an embodiment of the present invention, FIG. 1 is a view showing a cut piezoelectric ceramic resonator, and FIG.
FIG. 3 is a diagram showing a cross-sectional shape of the outlet of the extruder, FIG. 3 is a diagram showing a plate-shaped molded product having grooves, and FIG. 4 is a diagram showing a conventional piezoelectric ceramic resonator. 5 ... Groove, 6 ... Plate-shaped body, 7 ... Piezoelectric ceramic resonator, 8 ... Inclination of thickness.

Claims (1)

[Claims] 1. A piezoelectric ceramic resonator in which a plate-shaped molded body having a groove is formed by extrusion molding, and the piezoelectric molded body is divided into individual piezoelectric ceramic resonators having one or both ends inclined in thickness. Method.