JPH0744158Y2 - Piezoelectric electroacoustic transducer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a piezoelectric electroacoustic transducer using a vibration plate to which a piezoelectric material is attached.

[0002]

2. Description of the Related Art In recent years, for hearing aid users, there has been a handset used as a handset of a telephone with a coil for generating a magnetic flux of an audio signal. This coil is magnetically coupled to a pickup coil provided in the hearing aid and is used to induce an audio signal. Conventionally, it is well known that a piezoelectric type handset is partially used as a telephone handset, but the piezoelectric type handset cannot be magnetically coupled because there is no mechanism for generating a leakage magnetic flux. It was

In order to solve this drawback, the inventor of the present application has proposed Japanese Patent Application No. 2-11053 "Piezoelectric Electroacoustic Transducer" as shown in FIG. In FIG. 4, a piezoelectric vibrator in which one electrode 3-1 of the piezoelectric material 2 forming a pair on both sides is attached to the metal diaphragm 1 and two external terminals 18-1 connected to the pair of electrodes, A coil bobbin 21 around which a coil 22 is wound is provided so as to surround the metal diaphragm 1.

[0004]

In such a structure, the size of the metal diaphragm 1 is the coil bobbin 21.
Therefore, the piezoelectric material 2 needs to be sufficiently large in order to sufficiently maintain the sensitivity in the low frequency range, and the outer diameter of the metal diaphragm 1 also needs to be large in terms of acoustic characteristics. As a result, the outside diameter of the handset must be increased.

An object of the present invention is to solve these drawbacks and to provide a small size piezoelectric electroacoustic transducer having excellent acoustic characteristics.

[0006]

In order to achieve this object, a piezoelectric electroacoustic transducer according to the present invention is provided with a notch in a part of an outer edge portion of a metal diaphragm, and an electrode from a coil is cut into the notch. The piezoelectric vibrating plate and the coil are connected to each other by connecting to the conductive portion of the terminal plate through the section.

[0007]

Embodiments of the present invention will be described in detail below.
FIG. 1 shows a sectional view of an embodiment of the present invention. Here, 1 is a metal diaphragm, 2 is a piezoelectric material, and 3 is an electrode provided on both surfaces of the piezoelectric material. Reference numeral 4 denotes an insulating layer provided so as to cover a part of one electrode 3-2 of the piezoelectric material of the metal vibration plate 1, and reference numeral 5 denotes a conductive layer provided on the insulating layer 4. Reference numeral 21 is a coil bobbin around which the coil 22 is wound, and 22-1 is one of the electrodes of the coil 22. Reference numeral 17 is a terminal plate having a terminal 18 and a conductive pattern.

FIG. 2 shows an embodiment of the conductive pattern of the terminal board 17, which is 17-1, 17-2, 17-3.
Conductive patterns are provided. 1 of the conductive pattern
7-1 and 17-3 are connected to terminals 18-1 and 18-2 at their respective ends. Further, 9 is an acoustic leak hole, and 10 is a damper material. Here, 19 is an insulating layer provided so that the metal diaphragm does not contact the conductive pattern 17-1.

FIG. 3 shows a structure in which the metal vibrating plate 1 is fitted to the coil bobbin 21 in the embodiment. By disposing the terminal plate 17 on this surface, electrical continuity is established. It was done. 22-1, 22-2
Is a coil electrode in which lead wires (not shown) at both ends of the coil 22 are provided on the plane of the coil bobbin,
It is located in the recess of the outer edge of the metal diaphragm 1. In this embodiment, the electrical connection is from the terminal 18-1 through the conductive pattern 17-1 to the coil electrode 22-1, and from the other end 22-2 of the coil electrode to the conductive pattern 17-.
2 to reach the metal diaphragm 1 and reach the piezoelectric material 2 from one electrode 3-1 of the piezoelectric material 2. Furthermore, from the remaining electrode 3-2 of the piezoelectric material 2 to the terminal 1 through the conductive pattern 17-3.
It will reach 8-2. Therefore, the two terminals 18-
When 1 and 18-2 apply an audio signal to each other, an audio signal flows through the piezoelectric material 2 and the coil 22, whereby a leakage magnetic flux corresponding to the audio signal is generated in the coil 22.

Due to such a structure, the present invention can provide a metal diaphragm which is larger than the conventional one without contact between the coil electrodes 22-1 and 22-2 and the metal diaphragm 1. According to the present invention, even if the cutout portion of the metal diaphragm 1 is located at the outer edge portion, the acoustic characteristics are not hindered because the central portion has the recessed portion.

The shape of the notch according to the present invention is
Obviously, it is not necessary to refer to FIG. 3, and it is clear that the same effect can be obtained even in one place.

Further, the coil electrodes 22-1, 22-2
When insert molding the coil bobbin 21 with a resin material, insert a metal piece into the coil bobbin 21 or install the metal piece on the plane of the coil bobbin 21 afterwards to form a coil electrode 22-
1, 22-2 may be formed. In addition, the coil electrode 22
-1, 22-2 are not limited to metal pieces, and may be made of a conductive substance such as a conductive adhesive or a conductive rubber.

[0013]

As described above, according to the present invention,
Since the notch is provided at the outer edge of the metal diaphragm, and the coil electrode and the conductive pattern of the terminal plate are connected to the notch, there is an advantage of providing a piezoelectric electroacoustic transducer having a small size and excellent acoustic characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment according to the present invention.

FIG. 2 is a plan view showing an example of a terminal board used in an embodiment of the present invention.

FIG. 3 is a plan view showing a fitting state of a coil bobbin and a metal diaphragm according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing an example of a conventional piezoelectric acoustic transducer.

[Explanation of symbols]

 1 Metal Vibration Plate 2 Piezoelectric Material 3-1 and 3-2 Electrode 4 Insulating Layer 5 Conductive Member 9 Acoustic Leakage Hole 10 Damper Material 17 Terminal Plate 17-1, 17-2, 17-3 Conductive Pattern 18-1, 18- 2 External terminal 19 Insulating layer 21 Coil bobbin 22 Coil 22-1, 22-2 Coil electrode

Claims (1)

[Scope of utility model registration request] 1. An insulating layer is formed on at least a part of a surface of a metal vibrating plate having a piezoelectric material attached to a concave portion of a central portion thereof except the portion to which the piezoelectric material is attached, and the piezoelectric material A conductive layer is applied from one electrode to the insulating layer, a part of the metal diaphragm has a cut portion, and a coil is wound around a coil bobbin arranged so as to surround the metal diaphragm, A pair of coil electrodes is connected to the coil bobbin at both ends of the coil, and a conductive pattern is formed so as to be contact-connected by stacking the metal diaphragm, the conductive layer, and the pair of coil electrodes on one surface side. A terminal plate having an insulating layer applied to at least a part thereof, and contacting them in a stacked state with a metal cover so that a leakage magnetic flux due to an externally applied signal is generated from the coil. A piezoelectric electroacoustic transducer characterized by being constructed.