JPH07110080B2 - Piezoelectric device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a piezoelectric acoustic device such as a piezoelectric buzzer or a piezoelectric receiver using a piezoelectric element, and a method for manufacturing the same.

[Prior Art] A conventional piezoelectric acoustic device is one in which a piezoelectric diaphragm and a terminal plate are superposed and housed in a cap-shaped case, and the peripheral portion of the piezoelectric diaphragm is fixed to the peripheral portion of the case. . The piezoelectric diaphragm has a piezoelectric film formed on a conductor substrate.
Further, the terminal plate is a pair of terminal pins projecting from an insulating disc, and the terminal pins are connected to the conductor substrate of the piezoelectric vibrating plate and the piezoelectric film via a conductor film provided on the back surface of the terminal plate. Connected to.

Such a conventional piezoelectric vibrating device is disclosed in
It is known from the publication No. 68598. In the conventional piezoelectric acoustic device shown in this document, the peripheral portions of the piezoelectric vibrating plate and the terminal plate are directly overlapped with each other, and the conductor substrate and the piezoelectric film are not in contact with the two terminal pins in the overlapped peripheral portion. Has been planned. Therefore, in this conventional piezoelectric vibrating device, the piezoelectric vibrating plate and the terminal plate need to be in contact with each other only at their peripheral portions, so that the piezoelectric guiding plate is formed in an arm shape. Further, in order to connect the conductor substrate and the piezoelectric film to the two terminal pins in the peripheral part where the piezoelectric vibration plate and the terminal plate are overlapped, the extraction electrode is provided from the surface of the piezoelectric film to the peripheral part of the piezoelectric vibration plate. To be The extraction electrode is composed of, for example, a metal electrode plate made of aluminum foil or the like, a viscoelastic paint, an insulating adhesive tape, or the like.

[Problems to be Solved by the Invention] However, in the conventional piezoelectric acoustic device as described above, since the piezoelectric diaphragm and the terminal plate are brought into contact with each other only at their peripheral portions, it is necessary to form the piezoelectric diaphragm in the shape of an arm. There is. Therefore, the piezoelectric vibrating plate cannot be formed in a simple plate shape and needs to be formed in a special shape, which requires a lot of time and effort for molding, resulting in high cost. Further, since the piezoelectric vibration plate having a special shape is used, the sound pressure characteristics and the like are also adversely affected by the processing distortion and shape of the conductor substrate.

Further, in the above-described conventional piezoelectric acoustic device, since it is necessary to provide the extraction electrode from the surface of the piezoelectric film to the peripheral portion of the piezoelectric vibrating plate, the manufacturing of the piezoelectric vibrating plate is also troublesome and the cost is high. Moreover, since the extraction electrode is provided on the surface of the piezoelectric diaphragm, the sound pressure characteristic and the like are also adversely affected.

The present invention has been made in view of the above problems of the conventional piezoelectric acoustic device, and an object of the present invention is to provide a piezoelectric acoustic device that can be easily manufactured by using a simple flat piezoelectric acoustic device.

[Means for Solving the Problems] That is, the piezoelectric acoustic device according to the present invention includes a cap-shaped upper case 1, a circular lower case 5 into which the upper case 1 is fitted, and the upper case 1 and the lower case 5. A piezoelectric vibrating plate 2 housed in between and having a piezoelectric film 22 formed in a central portion on a conductor substrate 21, and terminal pins 41, 41 electrically connected to the front conductor substrate 21 and the piezoelectric film 22, respectively. Terminal plate 4 with protruding
And a conductive ring 3 is fitted between the peripheral surface portions of the conductor board 21 and the terminal plate 4, and the conductor board 21 is connected to one of the terminal pins 41 of the terminal board 4 via the ring 3. ,
A spring terminal 42, which is electrically connected to the other terminal pin 41, is brought into contact with the surface of the piezoelectric film 22 to be connected, and is provided on the insulating spacer material 6 provided on the inner peripheral portion of the upper case 1 and on the inner peripheral portion of the lower case 5, respectively. The peripheral parts of the conductor board 21 and the terminal board 4 are sandwiched between the upper case 1 and the lower case 5 from both sides via the adhesive 7, and the upper case 1 and the lower case 5 are separated by the adhesive 7. It is characterized in that they are fixed to each other.

Here, for example, the cap-shaped upper case 1 has a step portion 12 in its inner peripheral portion, and the insulating spacer material 6 made of silicone rubber is provided on the step portion 12.

[Operation] In the piezoelectric acoustic device according to the present invention, the conductive ring 3 is sandwiched between the peripheral surface portions of the conductor substrate 21 and the terminal plate 4, and the peripheral portion of the conductor substrate 21 and the terminal plate 4 holding the ring 3 therebetween. Are sandwiched from both sides by the upper case 1 and the lower case 5 via the insulating spacer material 6 and the adhesive 7 provided on the inner peripheral portions of the upper case 1 and the lower case 5, respectively. The piezoelectric vibrating plate 2 having any shape can be used. Since the insulating substrate 6 and the adhesive 7 surround the peripheral portion of the conductor substrate 21 and the terminal plate 4 that sandwich the ring 3, stable acoustic characteristics can be obtained.

Further, the conductor substrate 21 is connected to one terminal pin 41 of the terminal plate 4 via the ring 3, and the spring terminal 42 electrically connected to the other terminal pin 41 is brought into contact with the surface of the piezoelectric film 22 to be connected. Therefore, it is not necessary to provide an extraction electrode or the like on the piezoelectric diaphragm 2.

As a result, a piezoelectric acoustic device that can be easily manufactured and that has stable acoustic characteristics can be obtained.

[Examples] Next, examples of the present invention will be specifically described with reference to the drawings.

As shown in FIGS. 1 and 2, the piezoelectric acoustic device includes a piezoelectric vibrating plate 2, a ring 3 and a terminal plate between a cap-shaped upper case 1 and a ring-shaped lower case 5 fitted into the cap-shaped upper case 1. 4 is stored and fixed.

A through hole 11 is formed in the center of the top surface of the upper case 1 to release the sound generated by the vibration of the piezoelectric diaphragm 2 to the outside, and a step portion 12 formed by plastic working is formed on the periphery of the top surface. Has been done. The lower case 5 is formed such that the peripheral portion rises from the bottom surface portion, a large through hole is formed in the bottom surface portion, and the whole has a ring shape.

The piezoelectric vibrating plate 2 has a piezoelectric film 22 formed by piezoelectric ceramics on a conductive conductor substrate 21. The terminal board 4 is
A pair of terminal pins 41, 41 are provided on an insulating disk in a protruding manner. The terminal pins 41, 41 are provided with a conductive film provided on the back surface of the terminal plate 4 and a spring terminal 43 (see FIGS. 3 and 4). (See the figure). This terminal plate 4 is superposed on the electro-piezoelectric diaphragm 2 with a conductive ring 3 also serving as a spacer interposed therebetween, so that the conductor substrate 21 of the piezoelectric diaphragm 2 is connected to one terminal pin 41 via the ring 3. The piezoelectric film 22 is connected to the other terminal pin 41 via the spring terminal 42.

Here, in the piezoelectric acoustic device according to the present invention, as shown in FIG. 2, the adhesive 7 is provided over the entire circumference between the lower case 5 and the upper case 1 and between the lower case 5 and the terminal board 4. Is filled with
These are adhered to each other.

Next, a method for assembling and manufacturing the piezoelectric acoustic device will be described with reference to FIGS. 3 and 4.

First, as shown in FIG. 3 (a), the upper case 1 is turned upside down, that is, it is held horizontally with the top surface facing downward, and in this state, it is placed on the step 12 around the top surface. After applying the primer, the insulating spacer material 6 in a softened state is uniformly applied over the entire circumference. Subsequently, as shown in FIG. 2B, the peripheral portion of the piezoelectric vibration plate 2 is placed on the spacer material 6. In this state, the piezoelectric vibrating plate 2 receives the surface tension of the insulating spacer material 6 evenly from the surroundings and is naturally centered on the center of the upper case 1. It is desirable that the insulating spacer material 6 has appropriate viscosity in a softened state, has an appropriate curing time, and has insulating properties and stability. Silicone rubber is suitable as one having such conditions, for example, Toshiba. The best product is TSE387 made by Silicone.

Next, after the piezoelectric vibrating plate 2 is centered, the insulating spacer material 6 is hardened, but when the above silicone is used, it is left for 24 hours in the state shown in FIG. 2 (b). As a result, the insulating spacer material 6 in the softened state is hardened over time. After that, as shown in FIG. 3C, a conductive ring 3 also serving as a spacer is provided around the piezoelectric vibration plate 2.
And the terminal plate 4 is placed on this. As a result, the conductor substrate 21 and the piezoelectric film 22 of the piezoelectric vibrating plate 2 are respectively formed in FIG. 2 (c) by the conductor film and the spring terminal 42 formed on the lower surface of the terminal plate 4 in FIG. 3 (c). It is connected to the terminal pins 41, 41 protruding above the terminal plate 4.

Next, the process of the present invention is carried out, but here, the lower case 5 is upright, that is, upside down from that shown in FIG. -Apply the UV curable adhesive 7. Then, the lower case 5 is inverted as shown in FIG.
The outer case 1 is covered with the outer case 1 as shown in FIG. Then, the adhesive 7 permeates into the gap between the lower case 5 and the upper case 1 and the gap between the lower case 5 and the peripheral portion of the terminal board 4. Therefore, when a constant load is applied by placing a ring-shaped weight on the lower case 5, the adhesive 7 is hardened by its anaerobic curing property, and the lower case 5, the upper case 1 and the terminal board 4 are It is glued and fixed. Thereafter, the adhesive 7 that partially protrudes from the lower case 5 is irradiated with ultraviolet rays to cure the adhesive 7 in that part. The load applied to the lower case 5 to cure the adhesive 7 is generally around 170 to 200 g when the outer diameter of the lower case is around 33φ.

Through the steps described above, the piezoelectric acoustic device as shown in FIGS. 2 and 4 (b) is completed. In this state, the adhesive 7 is placed in the gap between the lower case 5, the upper case 1 and the terminal board 4.
Is filled and the airtightness of the inside is secured.

[Effects of the Invention] As described above, according to the present invention, a simple flat plate-shaped piezoelectric vibrating plate 2 can be used, and furthermore, an extraction electrode from the piezoelectric film 22 to the peripheral portion is not required, so that the manufacturing is easy. Moreover, it becomes possible to more easily manufacture and provide a piezoelectric vibration device having stable acoustic characteristics.

[Brief description of drawings]

FIG. 1 is a partially half-section exploded perspective view showing constituent members of a piezoelectric acoustic device, FIG. 2 is a half-sectional perspective view showing an embodiment of the piezoelectric acoustic device of the present invention, and FIGS. c) is a sectional side view in the order of steps showing an example of the previous step of the method for manufacturing a piezoelectric acoustic device according to the present invention, and FIGS. 4A and 4B are longitudinal cross sections in the order of steps showing the embodiment of the present invention. It is a side view. 1 ... Upper case, 2 ... Piezoelectric diaphragm, 3 ... Ring, 4
...... Terminal plate, 5 ...... Lower case, 7 ...... Adhesive, 12 ...... Lower case step, 21 ...... Piezoelectric diaphragm conductive substrate, 22 ...... Piezoelectric diaphragm piezoelectric film, 41 ...... Terminal Pin 42 ... Spring terminal

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuhiro Kanai 6-16-20 Ueno, Taito-ku, Tokyo Within Taiyo Electric Co., Ltd. (56) References JP-A-63-36700 (JP, A) JP-A-SHO 63-245000 (JP, A) Actual opening 57-166494 (JP, U) Actual opening 61-68598 (JP, U)

Claims (2)

[Claims] 1. A cap-shaped upper case (1), a circular lower case (5) fitted in the upper case (1), and a space between the upper case (1) and the lower case (5). And a piezoelectric vibrating plate (2) formed by forming a piezoelectric film (22) in the center of the conductor substrate (21), and electrically connected to the front conductor substrate (21) and the piezoelectric film (22), respectively. Terminal pin (41),
In a piezoelectric acoustic device having a terminal plate (4) provided with (41) protruding, a conductive ring (3) is fitted between the peripheral surfaces of the conductor substrate (21) and the terminal plate (4), The conductor substrate (21) is connected to one terminal pin (41) of the terminal plate (4) via the ring (3) and the other terminal pin (4) is connected.
A spring terminal (42) electrically connected to 1) is brought into contact with the surface of the piezoelectric film (22) to be connected thereto, and an insulating spacer material (6) and a lower case (5) respectively provided on the inner peripheral portion of the upper case (1). Through the adhesive (7) provided on the inner peripheral portion of the conductive substrate (2
1) and the peripheral portion of the terminal plate (4) are sandwiched between the upper case (1) and the lower case (5) from both sides, and the upper case (1) and the lower case (5) are sandwiched by the adhesive (7). )
A piezoelectric acoustic device characterized in that and are fixed to each other. 2. The cap-shaped upper case (1) has a step portion (12) in the inner peripheral portion thereof, and the step portion (12) is provided with an insulating spacer material (6) made of silicone rubber. The piezoelectric acoustic device according to claim 1, which is characterized in that.