JPH0728799Y2 - Piezoelectric electroacoustic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Field of Application of the Invention The present invention relates to a structure of a piezoelectric electroacoustic transducer using a piezoelectric diaphragm.

(2) Conventional technology and its problems Conventionally, a piezoelectric electroacoustic transducer of this type has been used as a practical technique.
There is one proposed in -7900.

That is, a piezoelectric vibrator in which one electrode of a piezoelectric ceramic element having a pair of electrodes on both sides is attached to a metal vibrating substrate, and a terminal plate having two external terminals respectively connected to the pair of electrodes. In the piezoelectric electroacoustic transducer provided with the above-mentioned vibrating substrate, a concave portion is formed in a central portion other than a peripheral portion, the piezoelectric ceramic element is attached to the concave portion, and the piezoelectric ceramic element on the vibrating substrate is An insulating layer is provided on at least a part of the surface other than the attached portion, and a conductive layer is applied from the other electrode different from the one electrode to the insulating layer, and the one surface of the terminal board is provided with the above-mentioned conductive layer. A first conductive pattern and a second conductive pattern, which are respectively connected to one and the other of the two external terminals, are adhered, and further, the front surface and the back surface of the insulator thin plate have the same or substantially the same shape. And a conductive plate on which the conductive patterns on the front surface and the back surface are connected to each other by the conductive paths, and the first plate is formed by stacking and coupling the piezoelectric vibrator, the conductive plate, and the terminal plate. Said conductive pattern is contact-connected to said conductive layer via said first conductive pattern of said conductor plate, and said second conductive pattern is said peripheral edge of said vibrating substrate via said second conductive pattern of said conductor plate. The structural feature is that it is configured so as to be contact-connected to and integrated with the section.

A conventional example will be described below.

FIG. 1 is a bottom view of the piezoelectric vibrator, and FIG. 2 is a sectional view thereof. Use the caulking structure with the front cover 6 to fix it. Here, 1 is a vibrating substrate made of a metal material, 2 is a piezoelectric ceramic element, 3 is an electrode provided on both sides of the piezoelectric ceramic element 2, and an electrode 3 on the vibrating substrate 1 side 3-
1 and an electrode 3-2 on the side opposite to the vibration substrate 1. Reference numeral 4 is an insulating layer provided on the surface of the vibrating substrate 1 on the piezoelectric ceramic element 2 side, and 5 is a conductive layer provided on the insulating layer 4 from the electrode 3-2 on the opposite side of the vibrating substrate 1. Electrode 3 on the vibration substrate 1 side
-1 is electrically connected to the vibration substrate 1. An insulating layer 4 is provided on at least a part of the surface of the vibrating substrate 1 on the side where the piezoelectric ceramic element 2 is attached, other than the surface on which the piezoelectric ceramic element 2 is attached, that is, approximately half in the illustrated case, and the vibrating substrate 1 and The conductive layer 5 is arranged so as not to contact, and a part thereof is connected to the electrode 3-2 on the side opposite to the vibration substrate 1.

FIG. 4 shows a terminal plate, and two conductive patterns 7-1 and 7-2 are provided on the terminal plate 7 in half.

FIG. 5 shows a conductor plate, which has a plurality of conductive patterns 9-1, 9 that are the same or substantially the same on both sides on the ring-shaped conductor plate 9.
-2 is provided, and each pattern on the front and back is a through hole
It is connected by 10 mag.

FIG. 3 is a cross-sectional view showing the lead-out structure of the piezoelectric vibrator of the embodiment, and one conductive pattern 7-1 is the terminal 8
-1 and the other conductive pattern 7-2 is terminal 8
-Conducts with -2. Therefore, the conductive layer 5 comes into contact with a part of the conductive pattern 9-1 of the conductor plate 9 and is electrically connected to a part of the conductive pattern 9-2 through the through hole 10 to form the conductive pattern 7-2 of the terminal plate 7. A portion 1-1, which is in contact with and on which the conductive layer 5 is not disposed, on the same circumference of the vibration substrate 1 on which the conductive layer 5 is disposed contacts the other part of the conductive pattern 9-2 of the conductor plate 9 to allow through. By electrically connecting the vibrating substrate 1 to the conductor plate 9 and the terminal plate 7 so as to conduct to the other part of the conductive pattern 9-1 through the hole 10 and come into contact with the conductive pattern 7-1 of the terminal plate 7. It can be easily integrated, and the terminal 8-1 and the electrode 3-1 are electrically connected, and the terminal 8-2 and the electrode 3-2 are electrically connected.

By applying a voltage between the two terminals 8-1 and 8-2, the terminal 8-1 vibrates through the [conductive pattern 7-1, 9-2, through hole 10, conductive pattern 9-1] to cause metal vibration. Board 1
The terminal 8-2 is electrically connected to the conductive layer 5 through the [conductive pattern 7-2, 9-2, through hole 10, conductive pattern 9-1].
To the electrodes 3-1 and 3 on both sides of the piezoelectric ceramic element 2.
A voltage is applied to -2.

In the above-described embodiment, since the concave portion is formed from below in the central portion of the vibration substrate 1 and the piezoelectric ceramic element 2 is attached to the concave portion, the conductive pattern 7-1 on the terminal board 7,
The contact between 7-2 and the electrodes 3-1 and 3-2 is stable, and in this embodiment, the conductive pattern of the conductor plate 9 is formed over the entire circumference and is further divided into individual conductive patterns. The conductive patterns 7-1 and 7-2 are not short-circuited and can be connected without special positioning of the contact portion at the time of stacking and coupling.

As described above, this piezoelectric electroacoustic transducer has a simple electrical connection with the external terminals of both electrodes of the piezoelectric ceramic element, and therefore has a simple assembly structure and is easy to manufacture, and is suitable for automated assembly. In addition, the volume of the air chamber can be freely changed by changing the shape and dimensions by using a conductor plate, and the fundamental resonance frequency is more stable and thinner than conventional piezoelectric electroacoustic transducers. It is easy to give the desired high sensitivity and wide band characteristics.

However, in this structure, as long as a conductor plate is used, when this conductor plate is manufactured, a copper clad laminate (both sides)
However, this work is extremely complicated, requires precise dimensional accuracy, requires a lot of manufacturing time, and is not economical. It has drawbacks.

(3) Purpose of the invention The invention is a piezoelectric electroacoustic transducer which is easy to manufacture by removing the conductor plate in order to eliminate these drawbacks, satisfies the precise dimensional accuracy, and is economical. To provide a container.

(4) Configuration and operation of the device To achieve this object, in the piezoelectric electroacoustic transducer of the present invention, one electrode of a piezoelectric ceramic element having a pair of electrodes on both sides is attached to a metal vibrating substrate. A piezoelectric vibrator, two conductor patterns formed on one surface for connecting to the pair of electrodes, two external terminals respectively connected to the two conductor patterns, and one surface to the other surface A terminal plate having a ventilation hole penetrating therethrough, and a small air chamber is provided between the terminal plate and the surface opposite to the piezoelectric vibrator side so as to cover the ventilation hole. And a back cover for forming, wherein the vibration substrate has a recessed portion formed in a central portion other than a peripheral portion, and the piezoelectric ceramic element is attached to the recessed portion,
An insulating layer is provided on at least a part of the surface of the vibrating substrate other than the part to which the piezoelectric ceramic element is attached, and a conductive layer is applied from the other electrode different from the one electrode to the insulating layer. The conductive layer comes into contact with one of the two conductor patterns by stacking and coupling the piezoelectric vibrator and the terminal plate, and the other of the two conductor patterns is provided with the insulating layer on the peripheral portion of the vibrating substrate. The air chamber formed between the vibrating substrate and the terminal plate is configured so as to communicate with the small air chamber through the ventilation hole. There is.

An embodiment of the present invention will be described below.

FIG. 6 shows an embodiment of the present invention and is a sectional view thereof. The piezoelectric vibrator is the same as that shown in FIG. 1 of the conventional example.

FIG. 8 shows a terminal board of the embodiment, in which two conductor patterns 27-1 and 27-2 are provided on the circular terminal board 27 so as to be located at both ends of one diameter, and the vent hole 27 is provided. −
3 is provided. This is the conventional terminal board 7 of FIG.
It corresponds to the one in which a ventilation hole 27-3 is added.

FIG. 9 shows a back cover 11 of the embodiment, which is a pressed part made of a metal material. Where the back cover
The shape of 11 is taken into consideration so as not to block the vent hole 27-3 of the terminal board 7.

FIG. 7 is a sectional view showing the lead-out structure of the piezoelectric vibrator of the embodiment. The front cover 6 and the vent hole 27-3 are omitted. One conductive pattern 27-1 is conductive with the terminal 8-1, and the other conductive pattern 27-2 is conductive with the terminal 8-2. Therefore, the conductive layer 5 is the conductive pattern of the terminal board 27.
On the same circumference of the vibrating substrate 1 on which the conductive layer 5 is arranged, the portion 1-1 on which the conductive layer 5 is not arranged is in contact with the terminal 27-2.
By stacking the back cover 11 on the terminal plate 27 so as to come into contact with the conductive pattern 27-1 of the above, it is possible to easily integrate them, and the terminal 8-1 and the electrode 3-1 are electrically connected,
Further, the terminal 8-2 and the electrode 3-2 are electrically connected.

By applying a voltage between the two terminals 8-1 and 8-2, the terminal 8-1 is electrically connected to the metal vibration substrate 1 through the conductive pattern 27-1, and the terminal 8-2 is connected to the conductive pattern 27-2. The conductive layer 5 is electrically connected to the electrodes 3-1, 3-2 on both sides of the piezoelectric ceramic element 2 by applying a voltage.

In the above-described embodiment, since the concave portion is formed in the central portion of the vibration substrate 1 from below and the piezoelectric ceramic element 2 is attached to the concave portion, the conductive pattern 27-1, on the terminal board 27,
The contact between 27-2 and the electrodes 3-1 and 3-2 is stable, and in this embodiment, the back cover 11 made of a metal material can be connected only by stacking and coupling it on the terminal board 27.

With such a configuration, in the piezoelectric electroacoustic transducer according to the present invention, the volume of the air chamber formed between the vibration substrate 1 and the terminal plate 27 is B, the volume of the vent hole 27-3 is C, and the terminal is 27. When the volume of the small air chamber 12 formed between the plate 27 and the back cover 11 is D, then AB + C + D (1). Here, A is the volume of the air chamber formed between the vibration substrate 1 and the terminal plate 27 in the conventional example as shown in FIG. This volume A is calculated by (B + C + D) as shown in equation (1).
Seed characteristics are similar to those of the conventional example shown in FIG. That is, it has been confirmed that the characteristics equivalent to those of the conventional example can be obtained even if the conductor plate 9 having a manufacturing problem is omitted.

(5) Effects of the Invention As described above, the piezoelectric electroacoustic transducer according to the present invention is simple in electrical connection with the external terminals of both electrodes of the piezoelectric ceramic element, so that the assembly structure is simple and the manufacturing is easy. .

Also, without using the conductor plate of the conventional example, a vent hole is provided in the terminal plate, the volume of the back cover and the volume of the air chamber can be freely changed, and the back cover is composed of press parts made of a metal material. By doing so, it is economical and it is possible to secure precise dimensional accuracy.

Furthermore, the piezoelectric electroacoustic transducer of the present invention can have the same characteristics as the conventional example.

[Brief description of drawings]

FIG. 1 is a plan view showing a structural example of a piezoelectric vibrator used in a conventional piezoelectric electroacoustic transducer, and FIGS. 2 and 3 are sectional views showing an example of the structure of a conventional piezoelectric electroacoustic transducer. FIG. 4 is a plan view showing a structural example of a terminal plate used in a conventional example, FIGS. 5 (a) and 5 (b) are plan views and sectional views showing a structural example of a conductor plate used in a conventional example, and FIG. FIG. 7 is a sectional view showing an embodiment of the invention, FIG. 7 is a sectional view showing an embodiment excluding the case of the piezoelectric electroacoustic transducer of the invention, and FIG. 8 is a plan view showing an example of the structure of a terminal plate used in the invention. FIG. 9 is a cross-sectional view for explaining a structural example of a back cover used in the piezoelectric electroacoustic transducer of the present invention. DESCRIPTION OF SYMBOLS 1 ... Vibrating substrate, 1-1 ... Portion on the vibrating substrate which is not provided with a conductive layer, 2 ... Piezoelectric ceramic element, 3,3-1, 3-2 ... Electrode, 4 ... Insulating layer, 5 ... Conductive layer, 6 ... Lead wire, 7,27 ... Terminal plate, 7-1,7-2,9-1,9-2,27-1,27-2 ... Conductive pattern, 8-1,8-2 ... Terminal, 9 ... Conductor plate, 10 ... through hole, 11 ... back cover, 12 ... small air chamber, 27-3 ... vent hole.

Claims (1)

[Scope of utility model registration request] 1. A piezoelectric vibrator in which one electrode of a piezoelectric ceramic element having a pair of electrodes on both sides is attached to a metal vibrating substrate, and formed on one surface to be connected to the pair of electrodes, respectively. A terminal plate having two formed conductor patterns, two external terminals respectively connected to the two conductor patterns, and a ventilation hole penetrating from one surface to the other surface, and the piezoelectric vibrator of the terminal plate. And a back cover for forming a small air chamber between the terminal plate and the vent hole on the side opposite to the side, and the vibrating substrate is recessed in a central portion other than the peripheral portion. Part is formed, the piezoelectric ceramic element is attached to the concave portion, an insulating layer is provided on at least a part of the surface of the vibration substrate other than the portion to which the piezoelectric ceramic element is attached, and the one electrode What is A conductive layer is applied from the different other electrode to the insulating layer, and the conductive layer contacts one of the two conductor patterns by stacking and coupling the piezoelectric vibrator and the terminal plate, and The other is brought into contact with and integrated with a portion on the peripheral portion of the vibrating substrate where the insulating layer is not applied, and an air chamber formed between the vibrating substrate and the terminal plate has the vent hole. A piezoelectric electroacoustic transducer configured to communicate with the small air chamber via the piezoelectric airacoustic transducer.