JPH04267296A - Piezoelectric buzzer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric buzzer used primarily as a source of alarm sound in home appliances, communication equipment, and the like.

0002

2. Description of the Related Art Conventionally, this type of piezoelectric buzzer has been constructed by bonding a piezoelectric ceramic plate 2 with electrodes 1 on both sides and a metal plate 3 made of iron-nickel, stainless steel, brass, etc. using an adhesive 4, as shown in FIG. The structure was glued together. and,
As the metal plate 3, brass is mainly used because of its cost advantage and easy availability.

0003

[Problems to be Solved by the Invention] In such a conventional configuration, when an alternating current signal of 500Hz to 5KHz is applied to make the piezoelectric buzzer sound, it generates 7K as shown by the dotted line in FIG.
Sound in the harmonic range from Hz to 15 KHz is generated, and good audio cannot be obtained due to the presence of harsh harmonic components. Note that the conventional sound pressure frequency characteristics shown by the dotted line in FIG. 3 are those when brass is used as the metal plate.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and aims to provide a piezoelectric buzzer capable of reducing the harsh harmonic portion of the sound.

[0005]

[Means for Solving the Problem] In order to solve this problem, the piezoelectric buzzer of the present invention includes a piezoelectric ceramic plate having electrodes formed on both sides, and a brass plate annealed at a temperature of 150°C to 400°C for 5 minutes or more. It is made by bonding these together with an adhesive.

[0006]

[Function] According to this configuration, by using an annealed brass plate as a metal plate, it is possible to reduce the rigidity and give elasticity without changing the specific gravity from the brass plate, so that the sound in the harmonic part that is harsh to the ear can be reduced. Thus, a piezoelectric buzzer with good sound quality can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a piezoelectric buzzer according to the present invention, and the same parts as in the conventional example are given the same numbers. In FIG. 1, 5 is a brass plate annealed at a temperature of 150°C to 400°C for 5 minutes or more, and this annealed brass plate 5 is bonded to a piezoelectric ceramic plate 2 with electrodes 1 formed on both sides as described above. (not shown in FIG. 1) to form a piezoelectric buzzer. In addition,
In FIG. 1, as in FIG. 2, lead wires for inputting electrical signals are omitted.

The solid line in FIG. 3 is a sound pressure frequency characteristic diagram of the product of the present invention.
FIG. 3 is a diagram showing the characteristics of a product using a partially annealed brass plate. As shown by the solid line in Figure 3, the product of the present invention can
The sound in the harmonic part of KHz is reduced compared to conventional products,
It can be seen that the sound pressure frequency characteristics have been improved.

[0009] Regarding the brass plate, if it is annealed at a temperature below 150°C, it will not have the effect of improving the sound pressure frequency characteristics, and if it is annealed at a temperature exceeding 400°C, the brass plate will This causes an oxide film to form on the surface, resulting in a loss of electrical conductivity. Furthermore, the brass plate was heated to 150℃~4
It was confirmed that even when annealing is performed at a temperature of 00°C, the above effects cannot be obtained if the annealing is performed for less than 5 minutes.

0010

Effects of the Invention As described above, according to the piezoelectric buzzer of the present invention, by using a brass plate annealed at a temperature of 150°C to 400°C for 5 minutes or more as a metal plate, the piezoelectric buzzer can maintain the same density as the brass plate. Since the rigidity can be lowered and elasticity can be imparted, the effect of reducing the harsh harmonic part of the sound and providing a piezoelectric buzzer with good sound quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a piezoelectric buzzer according to the present invention.

[Figure 2] Cross-sectional view showing a conventional piezoelectric buzzer

[Figure 3] Diagram showing the sound pressure frequency characteristics of the inventive product and the conventional product

[Explanation of symbols]

1 Electrode 2 Piezoelectric ceramic plate 5 Brass plate

Claims (1)

[Claims] 1. A piezoelectric buzzer comprising a piezoelectric ceramic plate with electrodes formed on both sides and a brass plate annealed at a temperature of 150° C. to 400° C. for 5 minutes or more, bonded together with an adhesive.