JPS6262699A - Piezoelectric sounding body - Google Patents

Abstract

PURPOSE:To enhacne a converting efficiency and improve a reliability to humidity and a thermal change by bonding a piezoelectric ceramic plate and a conductive plate by using an ultraviolet ray hardening and anaerobic resin component as a bonding agent. CONSTITUTION:A piezoelectric ceramic element plate has a shape of a thickness of 0.22mm, a diameter of 19.8mm, a diameter of an electrode of 18.2mm and a specific polarization processing is applied thereto. On both surfaces of such a piezoelectric ceramic element plate 2, electrodes 1, 1 are disposed, the piezoelectric ceramic element plate 2 and a conductive plate 4 for example, a brass of thickness 0.3mm and diameter 27mm are bonded by a bonding agent to have a piezoelectric sounding body. Therefor, an ultraviolet ray hardening and anaerobic resin component is used and irradiated for a specific time by an ultraviolet ray irradiating device and hardened. Herein, when constituting materials of the bonding agent are separately used as a bonding agent, a converting efficiency is high. The sounding body having the reliability to the humidity is inferior to a heat and impact resistance and the sounding body good for the heat and impact resistance shows a result that the reliability is small for the humidity. the present sounding body is good in the converting efficiency and has a good balance of the heat and impact resistance and a moisture resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a piezoelectric sounding body that is incorporated into various electronic circuits and used for notifications, alarms, etc. by emitting predetermined sounds as necessary.

<Conventional technology and its problems> As shown in the figure, a piezoelectric sounding element has a piezoelectric ceramic element plate 2.
An electrode 1.1 made of a metal film is provided on the entire both sides of the piezoelectric ceramic element plate 2, and a conductive plate 4 made of a metal plate is provided on one side of the piezoelectric ceramic element plate 2.
were obtained by joining them together via adhesive 3.

However, methods such as (1) adhesion using epoxy resin, (2) adhesion using anaerobic resin, and (2) adhesion using ultraviolet curing resin have been used to bond the piezoelectric ceramic element plate 2 and the conductive plate 4 together.

However, in the method (2), the sounding body with 1q has high conversion efficiency and high reliability against humidity, but has poor thermal shock resistance and is prone to cracks and cracks inside the piezoelectric ceramic element. In case of bonding with anaerobic resin (2), the protruding part of the adhesive does not become anaerobic and therefore does not harden.Therefore, this part needs to be cleaned, and this cleaning process adds one more manufacturing process, which poses a cost problem. It is. When adhering with the ultraviolet curing resin of Zaraani (■), the surface that cannot be irradiated with ultraviolet rays does not cure sufficiently.

Problems such as these have been pointed out, and it has not yet been possible to obtain a piezoelectric sounding body with good characteristics.

<Means for Solving the Problems> The present invention was made as a result of studies to solve the problems of the conventional piezoelectric sounding body as described above. The anaerobic resin composition used in combination is bonded with an adhesive to provide an excellent piezoelectric sounding body with high conversion efficiency and high reliability against humidity and thermal changes.

<Effect> This invention will be explained in detail below.

The shape of the piezoelectric ceramic element plate used in this invention is, for example, 0.22 mm in thickness, 19.8 mm in diameter,
The electrode has a diameter of 18.2 mm and can be polarized at 3 kV/mm for 10 minutes. Electrodes 1.1 are provided on both sides of the piezoelectric ceramic element plate 2, and the piezoelectric ceramic element plate 2 and the conductive plate 4 have a thickness of 0.3 mm and a diameter of 27 mm, for example.
In order to make a piezoelectric sounding element by bonding a brass plate of
Adhesion may be performed using an ultraviolet irradiation device having a wavelength of 65 nm and a mercury lamp of 80 W/cm for an irradiation time of 40 seconds and a fixing time of about 2 minutes.

The anaerobic resin composition combined with ultraviolet curing used as an adhesive in this invention is as follows: (A): Bisphenol-A 10-50 parts by weight dimethacrylate (B): Te1-La ethylene glycol 10-3Q
To u dimethacrylic acid 1 (C): Urethane acrylate 50-80 Prepolymer (100 parts by weight of A + B = 100 parts by weight) is the main component, and a polymerization initiator, a polymerization accelerator, a photosensitizer, and a polymerization It is a resin composition containing an inhibitor and the like.

The reason for limiting the materials A, B, and C, which are the main components in such an anaerobic resin composition combined with ultraviolet curing, to the above-mentioned range is because if the amount of material A is less than 10 parts by weight, the moisture resistance property will decrease. This is because if the amount exceeds 1 part by weight, the thermal shock resistance decreases. Also, when the amount of material B is 10 to 30 parts by weight,
If the amount is less than 10 parts by weight, the viscosity of the adhesive becomes high and the bonding operation becomes difficult, and if it exceeds 30 parts by weight, the adhesive strength decreases and a practical sounding body cannot be obtained.

If the amount of the material Rarani C is less than 50 parts by weight, the thermal shock resistance will decrease, and if it exceeds 80 parts by weight, the moisture resistance will decrease, so a range of 50 to 80 parts by weight is appropriate.

<Example> Dimethacrylate (B): Tetraethylene glycol 10 N dimethacrylate (C): Urethane acrylate 70 Prepolymer cumene hydroperoxy 4-dogide 3 P-benzophenone 3 Benzoic sulfimide
1.5 11 diethyl-P-toluidine 0,5〃
P-benzoquinone 0.01 #Using the ultraviolet curing anaerobic resin composition having the above composition as an adhesive, a piezoelectric ceramic element plate having electrodes on both sides and a brass plate were exposed to ultraviolet light with a dominant wavelength of 365 nm and a mercury lamp of 80 W/cm. A piezoelectric sounding body was obtained by bonding under the conditions of irradiation for 40 seconds using an irradiation device and fixing time of 2 minutes.

When the characteristics of the obtained piezoelectric sounding body were tested, the results shown in Table 1 were obtained.

Comparative Example 1 (A): Bisphenol A 100 parts by weight dimethacrylate cumene hydroperoxide 3 P-benzophenone 3 benzoic sulfimide
A piezoelectric sounding body was obtained in the same manner as in the example using a resin composition having the following composition as an adhesive: 1.5 diethyl-P-toluidine 0.5 P-benzoquinone 0.01 //.

Roughly, Comparative Example 2 is obtained by replacing (A>bisphenol-A dimethacrylate in Comparative Example 1 with (B) tetraethylene glycol dimethacrylate), and Comparative Example 3 is obtained by replacing (C) urethane acrylate prepolymer with (C) urethane acrylate prepolymer. Similarly, a piezoelectric sounding body of 1q was used.Since the piezoelectric sounding body of 1q from Comparative Example 2 was not practical, Comparative Example 1 was used.
A similar test was conducted on the piezoelectric sounding body obtained from 3.
Table 1 shows the results.

Table 1 Note *1: Humidity test: 85°C, 185%RH, 100H
It was conducted under the conditions of v.

*2: Thermal shock test: -55°C, 30 minutes 85°C, 3
It was performed in 10 cycles of 0 minutes.

<Effects of the Invention> From the above table, it can be seen that among the UV-cured anaerobic resin compositions used as adhesives in the present invention, comparative examples in which each of the constituent materials was used alone as an adhesive had high conversion efficiency and was resistant to humidity. In contrast, the piezoelectric sounding element of the present invention has good conversion efficiency and has poor thermal shock resistance, and those with good thermal shock resistance have poor reliability against humidity. It was also found to be highly reliable with a good balance of moisture resistance and thermal shock resistance.

[Brief explanation of the drawing]

The drawings are necessarily sectional views showing the structure of the piezoelectric sounding body.

Claims (2)

[Claims] (1) A piezoelectric sounding body characterized in that one side of a piezoelectric ceramic element plate having electrode films on both sides and a conductive plate are adhered with an anaerobic resin composition combined with ultraviolet curing. (2) Claim 1, characterized in that the UV-curable anaerobic resin composition is a resin composition whose main components are bisphenol-A dimethacrylate, tetraethylene glycol dimethacrylate, and urethane acrylate prepolymer. The piezoelectric sounding body described.