JPS6360617A - Manufacture of piezoelectric ceramic resonator - Google Patents

Abstract

PURPOSE:To reduce undesired thickness longitudinal vibration with good productivity by forming a slot to a flat plate forming by press processing, splitting the forming and giving a taper to the thickness of the circumference of the vibrator. CONSTITUTION:A flat plate forming body 5 made of a piezoelectric ceramic material is formed by extrusion forming or sheet forming. A pressure is exerted to the forming body 5 from both faces by using a press metallic mold to process the slot 6. Then sintering processing, electrode provision and polarization processing are applied to the plate, then the plate is cut and split to form a piezoelectric ceramic resonator 7. In such a case, the taper 8 is formed to the thickness of the circumference of each resonator 7 after cutting by the slot 6. Thus, the thickness is ununiformized and undesired thickness longitudinal vibration is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a piezoelectric ceramic resonator that functions as a filter or oscillator used in various electronic equipment such as communication equipment, video equipment, and audio equipment.

BACKGROUND OF THE INVENTION Piezoelectric ceramic resonators are used in various vibration forms depending on the frequency band used. In other words, from LF band to H
In the F band, longitudinal vibrations and spreading vibrations are used.
From the HF band to the 71 (F band), thickness vertical vibration, thickness shear vibration 2 surface acoustic wave vibration, etc. are used.The frequency constant is constant depending on the material, so the resonant frequency is determined by the dimensions of the resonator.Also, It is necessary to reduce vibrations other than those to be used to the necessary extent.

FIG. 4 shows the configuration of a conventional piezoelectric ceramic resonator using longitudinal vibration or spread vibration. In FIG. 4, 1 is a piezoelectric ceramic, and 2 and 3 are opposing types.

It is extreme. Such a piezoelectric ceramic resonator is manufactured by obtaining a plate-shaped sintered body, providing opposing electrodes on both sides, polarizing it, and then dividing it into individual piezoelectric ceramic resonators. Furthermore, as a method for obtaining a plate-shaped sintered body, one of the following three methods is used. That is, (1) A block-shaped sintered body is made and this is sliced into plate shapes. (2) Obtain a plate-shaped molded body by sheet molding and fire it. (2) A method in which a plate-shaped molded body is obtained by extrusion molding and then fired. Piezoelectric ceramics and Tsuku resonators (which use such longitudinal vibrations and spreading vibrations) are manufactured using abrasives, abrasive paper, etc. from the shape shown in Figure 4 in order to reduce unplanned thickening vibrations. Chamfering was done on the periphery.

Problems to be Solved by the Invention In such conventional manufacturing methods, the number of chamfering steps increases, and in order to efficiently chamfer, relatively coarse abrasives or abrasive paper are used, so corners are easily chipped. However, when the longitudinal vibration is used, unnecessary spurious waves tend to occur at the spreading vibration.

Furthermore, the chamfering is not uniformly performed, resulting in variations between the elements.

The present invention solves these problems, and aims to provide a method for manufacturing a piezoelectric ceramic resonator that is excellent in mass productivity and can reduce unnecessary vertical vibrations.

Means to Solve the Problems In order to solve the above-mentioned problems, the present invention obtains a flat plate-shaped molded product by extrusion molding or sheet molding, and applies pressure to the molded product from both sides using a press mold to form grooves. By processing and dividing each piezoelectric ceramic resonator, a part or all of the peripheral portion of each piezoelectric ceramic resonator is made to have a sloped thickness.

By using this method, the thickness is sloped around the periphery of the piezoelectric ceramic resonator, so that the dimension in which the thickness vertical vibration vibrates is no longer constant, and unnecessary thickness vertical vibration can be reduced. Moreover, since the thickness of the piezoelectric ceramic resonator is sloped when forming a continuous compact, it is excellent in mass production, and there is no need to roughen the end face as is the case when chamfering a sintered compact, resulting in excellent uniformity. It is something that exists.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

First, 4 parts by weight of methylcellulose, 6 parts by weight of propylene glycol, and microcrystalline wax are added to 10 parts by weight of a piezoelectric ceramic raw material having a composition of a three-component system of lead titanate, lead zirconate, and lead magnesium niobate with the addition of manganese dioxide. Add 1 part by weight and 15 parts by weight of water,
The raw materials for extrusion molding were prepared by mixing and kneading in a conventional manner, and extrusion molded using an extrusion molding machine into a flat plate-like molded body 4 having a thickness of 0.6 mm and a width of 120 mm as shown in FIG. This flat plate-shaped molded product 4 was dried appropriately so as not to stick to the press mold, and then cut into approximately 60 square pieces. Next, this plate-shaped molded body 6 is molded using a press mold (not shown).
Pressure was applied from both sides at a molding pressure of J, and grooves 6 were formed as shown in FIG. Next, this was fired, and silver paste was screen printed and baked on both sides. This was then polarized and cut into individual piezoceramic resonators having the shape shown in FIG.

At this time, a groove 6 formed by a press mold was used to form a slope 8 in thickness around the periphery of each piezoelectric ceramic resonator 7 after cutting. As a result, the thickness is no longer uniform, making it possible to reduce unnecessary thickness vertical vibrations in the resonator with spreading vibrations. However, compared to the conventional case where a sintered body is chamfered, unnecessary spurious waves are less likely to occur at the -spreading vibration.

In addition, 9.10 in FIG. 1 is a counter electrode.

In this embodiment, the thickness is sloped only on one side in the thickness direction, but it may be sloped on both sides. Also, although the entire peripheral portion is sloped in thickness, the same effect can be obtained even if only a portion of the thickness is sloped. Moreover, although the molded body was individually cut and divided after being fired and polarized nine times with electrodes, it may be divided into individual parts when it is made into a molded body, and then fired and polarized twice with electrodes. Furthermore, although a rectangular resonator is manufactured in this embodiment, a circular resonator is also possible. Further, although a flat plate-shaped molded body was obtained by extrusion molding, a resonator can be made in the same manner even if a flat plate-shaped molded body is obtained by sheet molding.

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 and spreading vibration with reduced unnecessary thickness vibration in a method suitable for mass production. This is extremely useful in practical terms.

[Brief explanation of drawings]

1 to 3 are diagrams explaining one embodiment of the present invention, in which FIG. 1 shows a cut piezoelectric ceramic resonator, and FIG. 2 shows a cut piezoelectric ceramic resonator.
The figure shows a flat plate-shaped molded body, Figure 3 shows a plate-shaped molded body grooved with a press mold, and Figure 4 shows a conventional piezoelectric ceramic S'7 resonator. . 4... Flat plate-shaped molded body, 6... Plate-shaped molded body, 6... Groove, 7... Piezoelectric ceramic resonator, 8... ...Thickness slope. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 6

Claims (1)

[Claims] A flat plate-shaped molded body is obtained by extrusion molding or sheet molding, and by applying pressure from both sides using a press mold to form grooves and dividing it, a part of the peripheral area of each piezoelectric ceramic resonator or A method of manufacturing a piezoelectric ceramic resonator whose thickness is sloped throughout.