JP2004104342A - Card type speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a card type speaker employing a piezoelectric element not producing a noise sound and a noise when a card is deformed. <P>SOLUTION: The card type speaker includes: a piezoelectric vibrator 20; a case 12 comprising a bottom wall on which the piezoelectric vibrator 20 is mounted and side walls for enclosing surroundings of the bottom wall to form an opening; and a cover 14 for covering the opening of the case; an enclosure for forming a space inside to contain the piezoelectric vibrator 20; a mount member 26 for supporting the piezoelectric vibrator 20 at its center for mounting on the bottom wall; and a contact preventing member 28 placed between the piezoelectric vibrator 20 and the bottom wall and fitted to the bottom wall so as to prevent the piezoelectric vibrator 20 from being in contact with the bottom wall. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric speaker, and more particularly to a card-type speaker using a piezoelectric element.
[0002]
[Prior art]
2. Description of the Related Art Recently, acoustic devices have been developed in which an ultra-thin speaker, a microphone, and a voice memory are incorporated in a business card size IC card having a thin card shape so that voice messages can be recorded and reproduced. A conventional voice coil type speaker is used as a speaker of such an IC card-shaped audio device. However, when the voice coil type speaker is miniaturized, the sound pressure level is remarkably reduced, and the sound level is reduced to a level suitable for use. When the pressure level is increased, the sound breaks and the voice cannot be heard clearly.
[0003]
2. Description of the Related Art In a piezoelectric speaker, for example, a speaker using a piezoelectric element as disclosed in Japanese Patent Application Laid-Open No. 2000-201398 or the like, it is possible to reproduce relatively faithfully the original sound even if the sound pressure level is increased. In the piezoelectric speaker disclosed in Japanese Patent Application Laid-Open No. 2000-201398, a columnar connecting portion is protruded inward from an inner surface of a central portion of an acoustic diaphragm forming a part of a housing, and a piezoelectric vibrator is fixed to the connecting portion. ing. In the piezoelectric speaker disclosed in this publication, a through hole is formed at the center of the piezoelectric vibrator, a connecting portion is inserted into the through hole, and heat is applied to the connecting portion and heat-fused to form a piezoelectric vibrator. Is fixed to the connecting portion.
[0004]
[Patent Document 1]
JP 2000-201398 A
[Problems to be solved by the invention]
Thus, it is conceivable to use a piezoelectric element as such a thin IC card-like speaker for audio equipment. However, when a piezoelectric speaker is incorporated in a thin IC card, there is a problem that when the card is deformed, the piezoelectric element comes into contact with the inner surface of the card to generate abnormal noise or noise. Further, in the piezoelectric speaker disclosed in Japanese Patent Application Laid-Open No. 2000-201398, an electric wire for applying an audio signal to the piezoelectric element is attached, and there is a problem that it is difficult to automatically assemble the piezoelectric speaker.
[0006]
An object of the present invention is to provide a card-type speaker using a piezoelectric element that does not generate abnormal noise or noise when the card is deformed. I have.
Still another object of the present invention is to provide a card-type speaker using a piezoelectric element that facilitates automatic assembly.
[0007]
[Means for Solving the Problems]
The present invention according to claim 1, in a card-type speaker, a case comprising: a piezoelectric vibrator; a bottom wall on which the piezoelectric vibrator is mounted; and a side wall surrounding four sides of the bottom wall to form an opening. A housing having a cover for closing the opening of the case, and forming a space for accommodating the piezoelectric vibrator therein, and a mounting member for supporting the piezoelectric vibrator at the center and mounting the piezoelectric vibrator on the bottom wall. A gist of the present invention is a card-type speaker including a contact preventing member attached to the bottom wall between the piezoelectric vibrating body and the bottom wall to prevent the piezoelectric vibrating body from contacting the bottom wall.
[0008]
According to another feature of the present invention, in a method for assembling a card-type speaker, a step of preparing a case having a bottom wall to which a piezoelectric vibrator is attached, and a side wall surrounding four sides of the bottom wall, A step of preparing a piezoelectric vibrator having a thin plate and a ceramic layer attached to one side of the thin metal plate; and a step of preparing a piezoelectric vibrator between the inner surface of the bottom wall of the case and the thin metal plate of the piezoelectric vibrator. The step of arranging a mounting member on the piezoelectric vibrating body by bonding between the metal thin plate of the piezoelectric vibrating body and the mounting member, and bonding between the mounting member and the inner surface of the bottom wall of the case. A step of attaching the piezoelectric vibrating body to a sound source while supporting the piezoelectric vibrating body to a sound source so as to be supported by a mounting member at the center of the ceramic vibrating body and a metal thin plate of the piezoelectric vibrating body. The process of attaching to the top surface and the cover Method of assembling a piezoelectric speaker comprising the step of closing the opening portion attached to the case is provided.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
In FIG. 1, the card-type speaker 10 includes a case 12 surrounding the piezoelectric vibrator 20 and a cover 14, and includes a housing that forms a space for accommodating the piezoelectric vibrator 20 therein. The housing may be in the form of a relatively thin card having a thickness of about 2.8 mm, for example, and may be formed of a plastic material such as ABS resin.
[0010]
The piezoelectric vibrator 20 includes a circular metal thin plate 22 made of a metal thin plate such as brass, for example, and a circular ceramic layer 24 attached to one side surface of the metal thin plate 22 with an appropriate adhesive. The ceramic layer 24 can be formed in a circular thin plate shape using a ferroelectric ceramic material such as barium titanate or lead zirconate titanate. Electric wires 16a and 16b are connected to the metal thin plate 22 and the ceramic layer 24, respectively. The piezoelectric vibrating body 20 is connected to an amplifier and other sound source devices (not shown) via the electric wires 16a and 16b. I have. This sound source device is normally disposed inside the housing, but may be outside the housing. In this case, an input terminal for connecting the electric wires 16a and 16b to an external sound source device is provided on the housing. In order to electrically connect the ceramic layer 24 to the metal thin plate 22 and the electric wire 16b, conductive layers (not shown) are formed on both sides of the ceramic layer 24 by a method such as silver plating.
[0011]
1 and 2, the piezoelectric vibrating body 20 is mounted on the bottom surface of the case 12 while being supported at the center by a mounting member 26. The attachment member 26 can be formed in a cylindrical shape from a plastic material such as an ABS resin, and has one end face (the upper end face in FIG. 1) below the metal thin plate 22 of the piezoelectric vibrating body 20 with an appropriate adhesive. The other end surface (the lower end surface in FIG. 1) is adhered to the bottom surface of the case 12 with an appropriate adhesive. In the present embodiment, a plurality of contact preventing members 28 are provided between the piezoelectric vibrating body 20 and the case 12 at the periphery. The contact prevention member 28 is formed of a flexible material such as foamed polyurethane, and is adhered to the bottom surface of the case 12 with an appropriate adhesive.
[0012]
Hereinafter, a method of assembling the card type speaker 10 will be described.
First, as shown in FIG. 1, a case 12 having a bottom wall to which the piezoelectric vibrator 20 is attached and side walls surrounding four sides of the bottom wall is prepared. Next, a piezoelectric vibrator 20 having a metal thin plate 22 and a ceramic layer 24 on one side surface of the metal thin plate 22 is prepared. Next, at least the mounting member 26 is arranged between the bottom surface of the case 12 (the inner surface of the bottom wall) and the thin metal plate 22 of the piezoelectric vibrator 20.
[0013]
Next, the piezoelectric vibrating body 20 is attached to the center of the piezoelectric vibrating body 20 by the attaching member 26 by bonding between the metal thin plate 22 of the piezoelectric vibrating body 20 and the mounting member 26 and between the mounting member 26 and the bottom surface of the case 12. It is attached to the bottom of the case 12 so as to support it. In this case, the mounting member 26 may be bonded to the bottom surface of the case 12 first, or may be bonded to the thin metal plate 22 of the piezoelectric vibrator 20. Further, the mounting member 26 may be simultaneously bonded to both the bottom surface of the case 12 and the metal thin plate 22.
[0014]
Next, the electric wires 16a and 16b are attached to the upper surfaces of the metal thin plate 22 and the ceramic layer 24 of the piezoelectric vibrator 20 by soldering or the like. In this case, in the present embodiment, the ceramic layer 24 is provided only on the side of the metal thin plate 22 opposite to the surface on which the mounting member 26 is attached. Can be inserted from the opening above the case 12. On the other hand, in the configuration disclosed in Japanese Patent Application Laid-Open No. 2000-201398, since the piezoelectric vibrator has the ceramic layers on both sides of the metal thin plate, a gap between the metal thin plate and the acoustic vibration plate is provided. It is difficult to attach the electric wire to the ceramic layer disposed on the substrate. In order to solve this problem, if wires are attached to the metal thin plate and the ceramic layers on both sides in advance, the wires are caught by the automatic assembly device for the piezoelectric vibrating body, which hinders automation of assembly. As is clear from the above description, according to the present embodiment, after attaching the piezoelectric vibrating body 20 to the bottom surface of the case 12, the electric wires 16a and 16b are connected to the metal thin plate 22 and the ceramic layer 24 through the opening of the case 12. The card type speaker 10 can be easily assembled.
[0015]
After attaching the electric wires 16a and 16b to the upper surfaces of the metal thin plate 22 and the ceramic layer 24 of the piezoelectric vibrator 20, the cover 14 is attached to the case 12, and the opening of the case 12 is closed to complete the card type speaker 10. When the sound source device is arranged in the housing, the connection between the electric wires 16a and 16b and the sound source needs to be made before the opening of the case 12 is closed by the cover 14, but the electric wires 16a and 16b and the piezoelectric The order of connection with the vibrating body 20 does not matter.
[0016]
In the card-type speaker 10 assembled in this manner, the piezoelectric vibrator 20 applies the audio signal from the sound source device between the metal thin plate 22 and the ceramic layer 24 via the electric wires 16a and 16b. Vibrates or bends in accordance with The vibration generated by the bending operation of the piezoelectric vibrating body 20 is transmitted to the bottom wall of the case 12 through the mounting member 26, and the bottom wall vibrates. The vibration of the bottom wall is further transmitted as sound to the surrounding air.
[0017]
The card type speaker 10 is easily deformed because the housings 12 and 14 are thin, and the bottom surface of the case 12 and the piezoelectric vibrator 20 are in contact with each other. When the piezoelectric vibrating body 20 comes into contact with the bottom surface of the case 12, abnormal noise or noise such as a so-called rattling sound is generated. In the present embodiment, the contact preventing member 28 prevents the contact between the piezoelectric vibrating body 20 and the bottom surface of the case 12 to prevent such abnormal noise or noise. Furthermore, in the above-described embodiment, the contact preventing member 28 is disposed between the piezoelectric vibrator 20 and the bottom wall of the case, but may be disposed between the piezoelectric vibrator 20 and the cover 14. Furthermore, it may be arranged both between the piezoelectric vibrating body 20 and the case 12 and between the piezoelectric vibrating body 20 and the cover 14. In addition, by preventing the contact preventing member 28 from contacting the piezoelectric vibrating body 20 in a normal use state, it is possible to improve the sound quality to be reproduced without hindering free vibration at the peripheral portion of the piezoelectric vibrating body 20. There is expected.
[0018]
Next, a second embodiment of the present invention will be described with reference to FIG.
In FIG. 3, the card-type speaker 30 includes a case including a case 32 and a cover 34 surrounding the piezoelectric vibrator 40. This housing can be in the form of a relatively thin card having a thickness of, for example, about 2.8 mm, similarly to the first embodiment, and can be formed of a plastic material such as ABS resin.
[0019]
The piezoelectric vibrator 40 includes a metal thin plate 42 and a circular ceramic layer 44 adhered to one side surface of the metal thin plate 42 with an appropriate adhesive. In order to connect the piezoelectric vibrator 40 to the sound source device, electric wires 36a and 36b are connected to the metal thin plate 42 and the ceramic layer 44, respectively. In order to electrically connect the ceramic layer 24 to the metal thin plate 22 and the electric wire 16b, a conductive layer (not shown) is formed on both sides of the ceramic layer 44 by a method such as silver plating. It is a shaking with the embodiment.
[0020]
In the first embodiment, the mounting member 26 is formed as a separate member from the case 12, but in the present embodiment, the mounting member is formed integrally with the case 42. That is, the center boss 32a protruding inward from the bottom surface is integrally formed as a mounting member on the bottom wall of the case 42. The piezoelectric vibrating body 40 is adhered to the end surface of the center boss 32a (the upper end surface in FIG. 3) on the lower surface of the metal thin plate 42.
[0021]
Further, as a contact preventing member for preventing the piezoelectric vibrating body 40 from contacting the peripheral boss 32b, a plurality of peripheral bosses 32b integrally formed so as to protrude inward from the bottom wall of the case 42, and a top surface of the peripheral boss 32b. A flexible synthetic resin 38 is provided in a gap between the piezoelectric vibrating body 40 and the metal thin plate 42. Preferably, a columnar projection 32c protruding upward is provided on the top surface of the peripheral boss 32b, and a small hole 42a for receiving the projection 32c is formed in the metal thin plate 42 of the piezoelectric vibrating body 40. Instead of the synthetic resin 38, a member formed in an annular shape from a flexible material such as polyurethane foam is fitted and arranged on the projection 32c so that the metal thin plate 42 of the piezoelectric vibrating body 40 does not come into contact in a normal use state. May be.
[0022]
【The invention's effect】
According to the first aspect of the present invention, even if the card is deformed, the piezoelectric vibrator does not come into contact with the housing, thereby preventing generation of abnormal noise and noise.
According to the third aspect of the present invention, since the electric wires are attached after attaching the piezoelectric vibrating body to the bottom wall of the case, it is not necessary to attach the electric wires to the piezoelectric vibrating body in advance. Automatic assembly of the card type speaker becomes easy.
[0023]
Furthermore, according to the present invention, since the mounting member for supporting the piezoelectric vibrator at the center and mounting the piezoelectric vibrator on the bottom wall of the case is mounted on the metal thin plate of the piezoelectric vibrator, the housing is deformed by external force acting thereon. Even when this occurs, there is no danger of the ceramic layer of the piezoelectric vibrating body breaking.
[Brief description of the drawings]
FIG. 1 is a sectional view of a card-type speaker according to a first embodiment of the present invention.
FIG. 2 is a plan view of the piezoelectric vibrator shown together with a mounting member and a contact preventing member, as viewed from a thin metal plate side.
FIG. 3 is a sectional view of a card-type speaker according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Card type speaker 12 ... Case 14 ... Cover 16a ... Electric wire 16b ... Electric wire 20 ... Piezoelectric vibrator 22 ... Metal thin plate 24 ... Ceramic layer 26 ... Mounting member 28 ... Contact prevention member

Claims (4)

In a card type speaker,
A piezoelectric vibrator,
A case comprising a bottom wall on which the piezoelectric vibrator is mounted and a side wall surrounding the four walls of the bottom wall to form an opening, and a cover closing the opening of the case. A housing forming a space for storage;
A mounting member for supporting the piezoelectric vibrator at the center and mounting the piezoelectric vibrator on the bottom wall,
A card type speaker comprising: a contact preventing member attached to the bottom wall between the piezoelectric vibrator and the bottom wall to prevent the piezoelectric vibrator from contacting the bottom wall. The piezoelectric vibrator includes a metal thin plate and a ceramic layer attached to one side surface of the metal thin plate, and the ceramic layer faces the opening in the housing toward the opening. The card-type speaker according to claim 1, which is attached. In the method of assembling the card type speaker,
A step of preparing a case having a bottom wall to which the piezoelectric vibrator is attached, and a side wall surrounding four sides of the bottom wall,
A step of preparing a piezoelectric vibrator having a metal thin plate and a ceramic layer attached to one side surface of the metal thin plate,
Disposing a mounting member between the inner surface of the bottom wall of the case and the thin metal plate of the piezoelectric vibrator,
By bonding between the thin metal plate of the piezoelectric vibrator and the mounting member, and between the mounting member and the inner surface of the bottom wall of the case, the piezoelectric vibrator is supported by the mounting member at the center thereof. Attaching to the bottom wall of the case in this way,
Attaching an electric wire for connecting the piezoelectric vibrator to a sound source to the upper surface of each of the ceramic layer and the metal thin plate of the piezoelectric vibrator,
Attaching a cover to the case and closing an opening of the case. 4. The method according to claim 3, further comprising the step of placing a contact preventing member between the piezoelectric vibrator and the bottom wall of the case before attaching the piezoelectric vibrator to the bottom wall of the case.

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