JPS583394A - Manufacture for piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To bond a piezoelectric element and a diaphragm with good adhesion without crack and break, by bonding the both through the provision of mechanical vibration with a minute amplitude. CONSTITUTION:A piezoelectric element base 11 having electrodes 11a and 11b on both major planes and a diaphragm 13 coated with an adhesives 17 are opposed. The base 11 is fallen down as the arrow to the plane with the adhesives and contacted and a mechanical vibration with a minute amplitude is given by operating an ultrasonic wave oscillator 13. The vacuum adsorbing force of the both is removed and the both are bonded by curing the adhesives 17. Thus, the adhesion of the both can be made without crack and break, allowing to increase the yield and the acoustic characteristics of the piezoelectric oscillator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a piezoelectric vibrator, and more particularly to a method of bonding a piezoelectric element substrate with a diaphragm that is integrated with the piezoelectric element substrate and generates sound waves using an adhesive.

The method of bonding the ceramic piezoelectric element substrate and the diaphragm in a conventional piezoelectric buzzer etc. is explained with reference to FIG. - After coating and baking the electrode at a temperature of around 800℃, polarization treatment is performed in a high electric field.
Then, adhesive 4 is placed on the thin metal diaphragm 3 held by the vacuum suction jig 2 using a dispenser method or the like, and the ceramic piezoelectric element substrate 1 is placed on top of the adhesive 4 using the vacuum suction jig 6. and hold it in the direction of the arrow with the vacuum suction jig 5 and 4. In this case, a method has also been proposed in which the ceramic piezoelectric element substrate 1 and the diaphragm 3 are held in the same manner as described above, and pressed down while applying relative rotation to bond the ceramic piezoelectric element substrate 1 and the diaphragm 3 together. (Utility Model Application No. 52-33277).

However, in such conventional methods, extremely thin ceramic piezoelectric elements with a thickness of 0.05 to 0.15 mm manufactured by the doctor blade method etc. are warped due to heat and electric field during electrode baking and polarization processing, and are then bonded together. As a result, ceramic piezoelectric elements are bonded by pressure contact or rotation using mechanical force with a large amount of movement. Therefore, the periphery of the ceramic piezoelectric element may crack during bonding, or in extreme cases may crack, reducing yield. In addition, in the case of a warped ceramic piezoelectric element substrate, an air layer is formed between the ceramic piezoelectric element substrate and the diaphragm, resulting in poor adhesion. In addition, in the case of pressure contact or rotation due to mechanical force with large movement, the electrode surface and diaphragm provided on the main surface of the ceramic piezoelectric element that is hit by the vacuum suction jig even if the ceramic piezoelectric element substrate is not applied or cracked. As the adhesion forces between the ceramic piezoelectric element and the adhesive and between the adhesive and the diaphragm increase, scratches may occur due to an imbalance in the suction force between the ceramic piezoelectric element and the diaphragm, resulting in damage to the piezoelectric buzzer. The acoustic characteristics and reliability of the

The disadvantage of these is that the vacuum suction force is strong in the suction direction, but part 9
There are four causes: it is weak against force from the 0 degree direction (rotation falls within this range) and the viscosity coefficient of the adhesive used is high.

This invention has been made in consideration of the above points, and aims to improve the adhesion between the piezoelectric element substrate and the piezoelectric element substrate without causing cracking or chipping when bonded with an adhesive, thereby improving yield and acoustic characteristics.・It provides a method.

In other words, this invention lowers the apparent viscosity coefficient of the adhesive by applying minute amplitude mechanical vibrations to the adhesive part when bonding the piezoelectric element substrate and the diaphragm, thereby creating an air layer between the piezoelectric element substrate and the diaphragm. The above objective is achieved by avoiding the occurrence of

Embodiments of the present invention will be described below with reference to the drawings. Second
The figure is a diagram for explaining one embodiment. Reference numeral 11 is a ceramic piezoelectric element substrate having electrodes 11h and 11bt on both main surfaces. , and is maintained. Reference numeral 18 denotes a diaphragm made of a thin metal plate, the surface of which is coated with an adhesive 17 by the screen inkuri method, and is held by suction by a vacuum suction jig 16. The vacuum suction jig 16 is made of resin and has a number of concentric holes 16a in order to make the vacuum suction force uniform, and is tightly inserted into a vacuum connecting device 15 having a vacuum device connecting part 14.・16 is placed on the ultrasonic vibration whale @13. In this way, the piezoelectric element substrate 1 and the diaphragm 18t are placed opposite each other, and the piezoelectric element substrate 11t? The ultrasonic vibrator IS is activated to apply mechanical vibrations of minute amplitude while the adhesive surface is lowered in the direction of the arrow and brought into contact with the adhesive surface.

Thereafter, the vacuum suction force between them is removed, and the integrated piezoelectric element substrate 11 and diaphragm 18 are placed in a constant temperature bath at around 100° C. and the adhesive 17t is cured and bonded.

Ultra-thin ceramic piezoelectric elements manufactured by the doctor blade method, etc., suffer from scratches during the manufacturing process as described above, but the amount of warpage (at the highest point around the concave ceramic piezoelectric element and at the lowest point at the center) According to the experimental manufacturing process conducted by Kagosha et al., the thickness of the ceramic piezoelectric element is 0.05.
~0.15 pieces, the outer diameter is 22-! Most of the work is 0.5- or less, and with this amount of warpage, the ceramic piezoelectric element substrate will not warp even if plastic deformation occurs to flatten it, so there is no problem with flattening it with a vacuum suction jig. According to this embodiment, by applying a small amplitude mechanical vibration to the adhesive part, the adhesive 17 changes from a state with a static viscosity coefficient to a state with a dynamic viscosity coefficient, and has an apparent viscosity coefficient. It is possible to improve adhesion and improve adhesion without interposing an air layer between the ceramic piezoelectric element substrate 11 and the movement plate 18. In this case, the adhesive with a reduced viscosity coefficient is used between the ceramic piezoelectric element substrate 11 and the diaphragm 18.
In between, it shows a capillary phenomenon and spreads toward the periphery of the ceramic piezoelectric element substrate 9 and moves from the center of the diaphragm 18 to the periphery, so that the generation of an air layer in the center is no longer allowed. According to the embodiment of the octopus, the effect of improving the yield and acoustic characteristics is obtained by eliminating the unreliable force caused by the large mechanical force that occurs in the past.

FIG. 3 shows an embodiment in which the ultrasonic vibration device is placed on the piezoelectric element substrate side. Although the same numbers as in FIG. 2 are given to the parts corresponding to those in FIG. 2 and detailed explanations are omitted, this embodiment also exhibits the same effects as the previous embodiment.

As described above, according to the present invention, by applying mechanical vibration of minute amplitude such as ultrasonic vibration to bond the piezoelectric element substrate and the diaphragm, the two can be bonded with good adhesion without causing cracking or chipping. It is possible to improve the pitch of the piezoelectric vibrator and improve the acoustic characteristics of the t-Fi.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the state of bonding conventional piezoelectric vibrators, FIG. 2 is an explanatory diagram of one embodiment of the bonding method of the present invention, and FIG. 3 is an explanatory diagram of the bonding method of another embodiment. be. 11...Ceramic piezoelectric element substrate% 11@eJJb
...electrode, lit, 16...vacuum suction jig, 13.
... Ultrasonic vibration device, 17... Adhesive, 18... Vibration plate.

Claims (3)

[Claims] (1) When manufacturing a piezoelectric vibrator tube by adhering a piezoelectric element substrate having electrodes on both sides to a vibrating plate, the piezoelectric element substrate and the vibrating plate are brought into opposing contact with an adhesive sandwiched between them, and the piezoelectric element substrate is bonded to a vibrating plate. A method for manufacturing a piezoelectric vibrator, in which S* involves applying mechanical vibration of minute amplitude to at least one of a diaphragm and a diaphragm and bonding the two. (2) The piezoelectric element exciter manufacturing method according to claim 1, wherein the adhesive is applied in advance to either the piezoelectric element substrate or the diaphragm by a printing method. (3) The method for manufacturing a piezoelectric vibrator according to claim 1, wherein the mechanical vibration is an ultrasonic vibration.