JPH0822114B2 - Method for manufacturing piezoelectric acoustic device - Google Patents

Description

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

[Prior Art] FIG. 1 is a view of the constituent members of a piezoelectric acoustic device viewed from the bottom side. The device includes a cap-shaped upper case 1 and a ring-shaped lower case 5 fitted therein. The diaphragm 2 and the terminal plate 4 are housed and fixed between the two. The vibrating plate 2 is formed by forming a piezoelectric film 22 on a conductor substrate 21. In the conventional piezoelectric acoustic device, for example, a silicon rubber or the like is provided on the step 12 formed on the peripheral portion of the top surface of the upper case 1. An insulative ring-shaped sheet (not shown) was placed on which the vibrating plate 2 was placed. The terminal plate 4 is formed by projecting a pair of terminal pins 41, 41 on an insulating disc. The terminal pins 41, 41 are provided on the back surface of the terminal plate 4 such as a conductor film or a spring terminal (first terminal). In the figure, it is hidden behind the back surface of the terminal board 4). The terminal plate 4 is superposed on the diaphragm 2 with a conductive ring 3 also serving as a spacer interposed therebetween, whereby the conductor board 21 of the diaphragm 2 is connected to one of the terminal pins 41 via the ring 3. The piezoelectric film 22 is connected to the other terminal pin 41 via the spring terminal.
In the conventional piezoelectric acoustic device, the upper case 1 and the lower case 5, which are fitted with the above-mentioned components sandwiched therebetween, are deformed and fixed by so-called caulking.

[Problems to be Solved by the Invention] However, the conventional piezoelectric acoustic device as described above has the following problems. That is, the inner diameter of the upper case 1,
The diameter of the diaphragm 2 is formed with a certain margin, but when the diaphragm 2 is placed on the ring-shaped sheet as described above, the diaphragm 2 and the diaphragm 2 are separated from each other. The center position easily shifts, and the position where the diaphragm 2 is incorporated into the upper case 1 differs for each product. The installation position of the diaphragm 2 with respect to the upper case 1, which also serves as a resonance box, has a delicate influence on the timbre of the piezoelectric acoustic device, so that a product with a different timbre will be produced for each individual product. .

An object of the present invention is to solve the above problems of the conventional piezoelectric acoustic device.

[Means for Solving the Problem] That is, the gist of the means adopted to achieve the above-mentioned object in the present invention is that a cap-shaped upper case 1 having a step portion 12 in the peripheral portion of the top surface, and the upper case 1 A ring-shaped lower case 5 that is fitted into the diaphragm 2, and a diaphragm 2 formed by forming a piezoelectric film 22 on a conductor substrate 21 and terminal pins electrically connected to the conductor substrate 21 and the piezoelectric film 22, respectively. In a method of manufacturing a piezoelectric acoustic device in which 41 and 41 are provided with a protruding terminal plate 4 and the upper and lower cases 1 and 5 are fixed to each other, the upper surface of the upper case 1 is held horizontally with the top surface side facing downward. At the same time, the insulating spacer material 6 in the softened state is applied to the stepped portion 12 around the same, the diaphragm 2 is placed on the insulating spacer material 6, and the diaphragm 2 is applied by the surface tension of the insulating spacer material 6 in the softened state. Center on the upper case 1 and then insulate spacer material It is a manufacturing method of a piezoelectric acoustic device for curing the.

[Operation] In the method of manufacturing the piezoelectric acoustic device according to the present invention, the diaphragm 2 is provided on the insulating spacer material 6 applied to the step portion 12 of the upper case 1.
Since the diaphragm 2 is centered with respect to the upper case 1 by holding the peripheral part of the same, and the peripheral edge of the diaphragm 2 is held by the upper case, the position of the diaphragm 2 with respect to the upper case 1 does not change. The diaphragm 2 can always be held in the center of the upper case 1.

In particular, in a state where the upper surface of the upper case 1 is held horizontally with the top surface facing downward, the insulating spacer material 6 in a softened state is applied to the step portion 12 around the upper case 1 and the diaphragm 2 is placed on the insulating spacer material 6. The diaphragm 2 is centered in the center of the upper case 1 by the surface tension uniformly received from the insulating spacer material 6 in the softened state.
Then, by curing the insulating spacer material 6 thereafter, the diaphragm 2 is always fixed to the center of the upper case 1.

[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 diaphragm 2, a ring 3, and a terminal plate 4 between a cap-shaped upper case 1 and a ring-shaped lower case 5 fitted therein.
Is stored and fixed.

A through hole 11 for releasing the sound generated by the vibration of the diaphragm 2 to the outside is opened in the center of the top surface of the upper case 1, and a step portion 12 formed by plastic working is formed in the peripheral portion of the top surface. ing. 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 diaphragm 2 has a piezoelectric film 22 formed by piezoelectric ceramics on a conductive conductor substrate 21. The terminal board 4 is an insulating disk having a pair of terminal pins 41, 41 projecting from it.
The terminal pins 41, 41 are electrically connected to a conductor film or a spring terminal provided on the back surface of the terminal plate 4. The terminal plate 4 is superposed on the diaphragm 2 with a conductive ring 3 also serving as a spacer interposed therebetween, whereby the conductor board 21 of the diaphragm 2 is connected to one of the terminal pins 41 via the ring 3. The piezoelectric film 22 is connected to the other terminal pin 41 via the spring terminal.

Here, in the piezoelectric acoustic device according to the present invention, as shown in FIG. 2, the peripheral portion of the diaphragm 2 is held by the insulating spacer material 6 on the step portion 12 formed in the peripheral portion of the top surface of the upper case 1.

Next, a method of 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 held upside down, that is, the upper surface is held horizontally with the top surface facing downward,
In this state, a primer is applied on the step portion 12 in the peripheral portion of the top surface, and then the insulating spacer material 6 in a softened state is uniformly applied over the entire circumference. Subsequently, as shown in FIG. 3B, the peripheral portion of the diaphragm 2 is placed on the spacer material 6. As described above, in this state, the vibration plate 2 has the insulating spacer material 6
The surface tension is evenly received from the surroundings, and the center of the upper case 1 is naturally centered. 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 diaphragm 2 is centered, the insulating spacer material 6 is cured. When using the above silicone, leave it in the state shown in FIG. 2 (b) for about 24 hours. Thereby, the insulating spacer material 6 in the softened state is cured with time. Then, as shown in FIG.
A conductive ring 3 which also serves as a spacer is placed on the peripheral portion of, and the terminal plate 4 is placed on this. As a result, the terminal board 4
3 (c), the conductor film 21 and the piezoelectric film 22 of the vibrating plate 2 respectively protrude above the terminal plate 4 in FIG. 2 (c) by the conductor film and the spring terminal formed on the lower surface. Connected to terminal pins 41, 41.

Next, the lower case 5 is erected, that is, upside down from that shown in FIG. 4 (a), and an anaerobic curable / ultraviolet curable adhesive 7 is applied to the periphery of the inner bottom surface thereof. Then, the lower case 5 is inverted as shown in FIG.
This is put on the outside of the upper case 1 as shown in FIG. Then, the adhesive 7 is provided in the gap between the lower case 5 and the upper case 1 and in the gap between the lower case 5 and the peripheral portion of the terminal board 4.
Penetrates. Therefore, when a constant load is applied by placing a ring-shaped weight on the lower case 5, the adhesive 7 is cured by its anaerobic curing property, and the lower case 5 and the upper case 1
Also, it is adhered and fixed from the terminal board 4. 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 filled in the gap between the lower case 5, the upper case 1 and the terminal plate 4 to ensure the airtightness of the inside.

[Effects of the Invention] As described above, according to the present invention, a piezoelectric acoustic device in which the vibration plate 2 is held in the center of the upper case 1 is obtained, and a piezoelectric vibration device having a constant timbre is manufactured and provided at a high yield. It becomes possible to do.

[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. FIG. 4C is a vertical sectional side view showing the embodiment of the method for manufacturing a piezoelectric acoustic device according to the present invention in the order of steps, and FIGS. 4A and 4B are vertical sectional side views showing the latter half of the step of assembling the piezoelectric acoustic device. It is a figure. 1 ... Upper case, 2 ... Vibration plate, 3 ... Ring, 4 ... Terminal plate,
5 ... Lower case, 6 ... Insulating spacer material, 12 ... Step of lower case, 21 ... Conductor substrate of diaphragm, 22 ... Piezoelectric film of diaphragm, 41 ...
Terminal pin

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuhiro Kanai 6-16-20 Ueno, Taito-ku, Tokyo Within Taiyo Denki Co., Ltd. (56) References: 62-86799 (JP, U) 56-167397 (JP, U)

Claims (1)

[Claims] 1. A piezoelectric film 22 is formed on a conductor substrate 21 between a cap-shaped upper case 1 having a step portion 12 in the peripheral portion of the top surface and a ring-shaped lower case 5 fitted in the upper case 1. The vibrating plate 2 formed and the terminal plate 4 on which the terminal pins 41, 41 electrically connected to the conductor substrate 21 and the piezoelectric film 22, respectively, are housed, and the upper and lower cases 1, 5 are accommodated. In a method for manufacturing a piezoelectric acoustic device in which the two are fixed to each other, the upper surface of the upper case 1 is held horizontally with the top surface facing downward, and the insulating spacer material 6 in a softened state is applied to the step portion 12 around the upper surface of the upper case 1. The vibrating plate 2 is placed on the insulating spacer material 6, the vibrating plate 2 is centered with respect to the upper case 1 by the surface tension of the softened insulating spacer material 6, and then the insulating spacer material 6 is cured. Method for manufacturing piezoelectric acoustic device.