JPH0698397A - Piezoelectric sound generator - Google Patents

Abstract

PURPOSE:To prevent the waterdrops, the moisture, etc., from entering a sound generator by providing a waterproof sheet at the opening edge of a storing case and also by providing the waterproof sheet on the mounting surface of the attachment base member of a handset main body via a non-permeable and elastic member. CONSTITUTION:A projecting part 83 for matching is provided on the mounting surface 84 of an attachment base member 81 of a handset main body 80 in accordance with the shape of an opening edge 55 of a storing opening 52 of a piezoelectric sound generator 90. Thus the edge 55 of a case 51 of the generator 90 is matched with the part 83 on the surface 84 and fixed there by pressure. Then the generator 90 is put on the member 81. Under such conditions, a waterproof sheet 72 provided along the edge 55 covers the entire opening surface and also the peripheral part touching the edge 55 is pressed onto the surface 84 via an elastic rubber ring 26. In such a constitution, the external waterdrops, moisture, etc., can be completely prevented from entering the generator 90 through a sound vent hole 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called cordless telephone having a handset and a telephone body which are separated from each other to transmit and receive voice by wireless communication, and a portable telephone which can be freely carried. In regard to an electroacoustic transducer, a so-called piezoelectric sounding body, which is built in a transmitter or a receiver and configured to convert a voice signal and a voltage value, more specifically, the telephone is used in a bathroom or a washbasin. The present invention relates to a piezoelectric sounding body which is configured to prevent water droplets, moisture, etc. from entering when used in a place where water is splashed or in a high humidity environment, and that sound pressure deterioration due to the waterproof measure is small. .

[0002]

2. Description of the Related Art In response to the era of advanced information technology in recent years, various kinds of information provision or telephone calls have come through a telephone line.
For example, a telephone set with measures against water drops and humidity so that it can be used even in a hot and humid environment is desired.

In particular, a so-called cordless telephone, in which the transmitter / receiver and the telephone body are separated and transmitted and receives voices by wireless communication, can be moved indoors. It is inevitable to use it in a bathroom or washroom in a hot and humid environment, and countermeasures against water drops and humidity are necessary.

Further, mobile phones that can be carried around freely are rapidly becoming widespread due to the expansion of service networks and price reductions, but when used outdoors, reliability that can withstand severe operating environments is required. Therefore, it is necessary to take measures against water drops and moisture as a matter of course.

On the other hand, there is a strong demand for miniaturization of the cordless telephones and portable telephones, but this is combined with the fact that the built-in radio communication electronic circuit, power supply section and the like require a certain volume. Therefore, it is inevitable to make the handset part smaller and thinner.

In order to satisfy the above requirements, a piezoelectric sounding body incorporating a piezoelectric vibrating plate utilizing a piezoelectric action is adopted in place of an electromagnetic speaker utilizing an electromagnetic action which has been conventionally used in a transmitter and a receiver. Has reached the end.

At present, the piezoelectric sounding body is being developed in order to meet the demands for higher sound pressure and improved mountability in addition to the original characteristics of small size, thinness and power saving.

The conventional piezoelectric sounding body to which the piezoelectric vibrating plate is applied and the structure in which the piezoelectric sounding body is attached to the main body of the handset will be outlined with reference to the sectional view of FIG.

First, the piezoelectric element 21 is an element for performing piezoelectric acoustic conversion, and is formed in a thin disk shape with a material of ferroelectric ceramics that causes dielectric polarization when a force is applied.

Electrodes are formed by coating on both end faces of the piezoelectric element 21.

The piezoelectric element 21 having the electrodes formed thereon has one electrode interposed on the diaphragm surface 22a of the diaphragm 22 which is larger than the piezoelectric element 21 and is formed in a thin disk shape. The piezoelectric vibration plate 20 is configured by being fixed.

Although not shown, the piezoelectric vibrating plate 20 is also provided.
At one end of the other electrode attached to the piezoelectric element 21 and one end of the vibration plate surface 22a, an insulating coating conductor for exchanging an electric signal with the outside is soldered and fixed, and It is assumed that the piezoelectric vibration plate 20 is led out from the housing case 11 that serves as a housing base.

Next, the storage case 11 is made of synthetic resin or the like, has a side wall having an annular shape or a polygonal shape, a storage opening 12 having one surface entirely opened, and the storage opening 12
By having the opening relative wall portion 19 facing each other, the cross section is formed into a substantially concave shape.

A braking hole 13 is opened in a substantially central portion of the opening relative wall portion 19, and a sound pressure adjusting film 18 formed in a mesh shape is covered inside the storage case 11 in the braking hole 13. Further, the sound pressure-frequency characteristic of the piezoelectric vibration plate 20 with respect to the piezoelectric vibration can be adjusted by being fixed by an adhesive.

A mounting step portion 14 is provided on the inner wall surface of the housing case 11 at a substantially central portion thereof over the entire inner surface thereof, and the piezoelectric vibrating plate 20 allows the piezoelectric element 21 to face the opening relative wall portion. The mounting step portion 1 is housed in the housing case 11 through the housing opening 12 so as to face the 19 side.
In FIG. 4, the vibrating plate peripheral portion 22b of the piezoelectric vibrating plate 20 is brought into contact with the piezoelectric vibrating plate 20, and is further fixed by, for example, a silicone sealing adhesive 16.

Next, a state in which the piezoelectric sounding body 10 configured as described above is attached to the handset main body 30 of the telephone will be described.

In FIG. 2, the transmitter / receiver main body 30 shows a mouthpiece portion or an earpiece portion, which is a main part of the present invention, and this portion is provided on an attachment base material 31 to which the piezoelectric sounding body 10 is attached. Has become.

Sound holes 32, 32 '... For passing a transmission sound or a reception sound are opened in the mounting base material 31.

Further, on the mounting surface 34 of the mounting base material 31 of the handset main body 30, there is provided a fitting convex portion 33 corresponding to the shape of the opening edge 15 on the storage opening 12 side of the pressure transmitting member 10. It is projected.

In this state, the opening edge 15 of the housing case 11 of the piezoelectric sounding body 10 is fitted into the fitting convex portion 33 on the mounting surface 34 and is fixed by adhesion, whereby the piezoelectric sounding body is produced. 10 is mounted on the mounting substrate 31.

At this time, the rubber ring 2 which is a non-air-permeable elastic member is provided around the opening edge 15 of the storage case 11.
The waterproof sheet 25 is pressed against the mounting surface 34 so as to close the entire opening through 6, and the sound-permeable holes 32, 32
It has a structure that prevents the intrusion of water droplets or moisture from the outside through ´….

The waterproof sheet 25 is made of a material having a certain degree of breathability so that voices and the like can pass therethrough, and having water repellency for preventing water drops, moisture, etc.

[0023]

However, according to the structure of the conventional piezoelectric sounding body 10 described above, the waterproof sheet 25 is used.
Is the mounting surface 34 of the mounting base material 31 in the handset main body 30.
Since the peripheral portion of the waterproof sheet 25 is pressed against the mounting surface 34 by the rubber ring 26, which is an elastic member, while being in contact with, the waterproof sheet 25 itself can hardly vibrate and has a certain degree of air permeability. However, it causes the deterioration of sound pressure.

That is, in the transmitter, the sound passage holes 32, 32
Changes in the sound pressure of the speaker's voice through the ´… piezoelectric piezoelectric plate 2
0 becomes an obstacle that makes it difficult to transmit to 0, and in the receiver, changes in sound pressure due to the sound of the piezoelectric diaphragm 20 are transmitted through the sound passage 3
There is a problem that it becomes an obstacle that makes it difficult to convey to the listener through 2, 32 ', and causes a decrease in sound pressure.

The present invention has been made in view of the above circumstances, and when the cordless telephone or the portable telephone is used in a bathroom or washroom or the like in a water-spraying or humid environment, for example, it may be exposed to water drops or the like. (EN) Provided is a piezoelectric sounding body having a structure in which water droplets or moisture is prevented from entering and a deterioration in sound pressure is reduced so that a continuous call can be made even if landing occurs.

[0026]

SUMMARY OF THE INVENTION According to the present invention, one side is opened on the whole surface and a storage case having a braking hole in a wall portion facing the opening, and a piezoelectric element is fixed on the surface of a vibration plate and the vibration is generated. A piezoelectric vibrating plate whose peripheral portion is fixed to the inside of the storage case, and a waterproof sheet in which the peripheral portion is attached to the opening edge so as to block the entire opening of the storage case and which can freely vibrate. The above object is achieved by providing a piezoelectric sounding body comprising: a non-breathable elastic member mounted along the periphery of the stretched waterproof sheet.

[0027]

In the present invention, a waterproof sheet is attached to the edge of the opening so as to close the entire opening of the storage case in which the piezoelectric vibrating plate is stored, and the waterproof sheet is a non-breathable elastic member (rubber ring). Etc.) is disposed on the mounting surface of the mounting base material in the handset main body, so that the inside of the storage case is completely kept airtight by the waterproof sheet and the air-impermeable elastic member, and It is possible to prevent water droplets and humidity in the external environment from entering the inside of the storage case through the sound passage holes formed in the mounting surface. Therefore, the piezoelectric element and the like in the storage case are protected from deterioration of reliability due to water or moisture.

Further, since the mounting surface of the mounting base material in the handset main body and the waterproof sheet do not come into contact with each other, a gap corresponding to the thickness of the cross-section of the non-air-permeable elastic member (rubber ring or the like) is maintained. It is possible to vibrate freely within the gap.
Therefore, the sound pressure due to the vibration of the piezoelectric diaphragm of the earpiece is transmitted through the sound passage without being significantly deteriorated, and conversely, the sound pressure of the voice of the speaker of the transmitter is not significantly deteriorated. It will be transmitted to the piezoelectric diaphragm through the through hole.

[0029]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a mounting structure for a piezoelectric speaker according to the present invention.

In FIG. 1, one side of the piezoelectric sounding body 90 is opened, and a wall portion 59 facing the opening 52 is formed.
A storage case 51 having a braking hole 53 in the inside, a piezoelectric element 61 fixed to a surface 62a of a vibration plate 62, and a peripheral portion 62a of the vibration plate fixed inside the storage case 51; A peripheral portion is attached to the opening edge 55 so as to close the entire surface of the opening 52 of the storage case 51, and a waterproof sheet 72 vibrable by sound pressure, and a non-ventilated sheet adhered along the peripheral portion of the waterproof sheet. Elastic member 91, and the opening edge 55 has the handset main body 8
The piezoelectric sounding body 90 is mounted on the mounting base material 81 by being fitted and fixed to the fitting convex portion 83 on the mounting surface 84 of the mounting base material 81 of No. 0.

At this time, the non-air-permeable elastic member 91 is mounted on the waterproof sheet 72 attached to the opening edge 55, but when the piezoelectric sounding body 90 is detachably mounted on the mounting base 81. The waterproof sheet 72 may be held in a mounted state with a gap corresponding to the thickness of the cross section of the non-air-permeable elastic member 91 from the mounting surface 84 in the mounted state.

Next, each member used in the piezoelectric sounding body 90 according to the present invention will be described in detail.

A piezoelectric element 61 having a piezoelectric effect that causes polarization when a pressure or a tension is applied to a ferroelectric substance to generate an electrostatic charge on the end face or an electrostrictive effect that causes a mechanical stress when an electric field is applied is a PZT ( Lead zirconate titanate) Ceramics and other ferroelectric ceramics with a thickness of 50 μm
It is formed in a thin disk shape of about 100 μm.

Electrodes are formed on both end faces of the piezoelectric element 61 by depositing a metal having good electric conductivity such as silver in a thin film shape.

The piezoelectric element 61 on which the electrodes are formed is made of brass or the like, is larger in size than the piezoelectric element 61, and is formed on a vibrating plate surface 62a of a vibrating plate 62 formed in a thin disk shape.
The piezoelectric vibrating plate 60 is configured by being fixed via one electrode.

The vibrating plate 62 serves as a base material for mounting the piezoelectric element 61 and is provided to mediate piezoelectric vibration.

Although not shown, the piezoelectric vibrating plate 60 is also provided.
At one end of the other electrode attached to the piezoelectric element 61 and one end of the vibration plate 62, an insulating coated conductor wire for exchanging an electric signal with the outside is soldered and fixed, and It is assumed that the diaphragm 60 is derived from the housing case 51 that serves as a housing base.

The storage case 51 is made of synthetic resin or the like, has a side wall having an annular shape or a polygonal shape, a storage opening 52 having one surface opened, and an opening relative wall portion 59 facing the storage opening 52. By having and, the cross section is formed in a substantially concave shape.

A braking hole 53 is opened in a substantially central portion of the opening relative wall portion 59, and a mesh-shaped sound pressure adjusting film 58 covers the braking hole 53 inside the storage case 51. The sound pressure for the piezoelectric vibration of the piezoelectric vibration plate 60 is adjusted by being fixed by the fixing adhesive 57.

A mounting step portion 54 is formed on the inner wall surface of the housing case 51 over the entire circumference of the inner surface, and the piezoelectric vibrating plate 60, in this example, the piezoelectric element 61 and the opening relative wall portion. It is housed in the housing case 51 through the housing opening 52 so as to face the 59 side, and at the mounting step portion 54, the diaphragm peripheral portion 62b of the piezoelectric diaphragm 60.
Are abutted against each other and further fixed by, for example, a silicone-based sealing adhesive 56.

At this time, by the sealing adhesive 56,
The vibrating plate peripheral portion 62b of the piezoelectric vibrating plate 60 is coated over the entire circumference of the mounting step portion 54 of the storage case 51, and the storage opening 62 is closed at the first mounting step portion 54. .

Further, the storage opening 5 of the storage case 51.
The end surface on the second side has an opening edge 55, and the opening edge 55 has a certain degree of breathability and is made of a water-repellent material that drip-proofs water drops or moisture. The seat 72 is stretched so as to close the storage opening 52 by fixing the peripheral portion 69 with, for example, an adhesive material.

Further, the stretched waterproof sheet 72 is provided.
A rubber ring, which is a non-breathable elastic member 91 having elasticity for exerting a buffering function and having non-breathability for preventing permeation of gas or liquid or the like, is adhered on the peripheral portion abutting the opening edge of It is fixed with a material or the like, or is attached in a detachable state.

Next, a state in which the piezoelectric sounding body 50 configured as described above is attached to the handset main body 80 of the cordless telephone or the portable telephone will be described.

In FIG. 1, the transmitter / receiver main body 80 shows a mouthpiece portion or an earpiece portion, which is a main part of the present invention, and the portion is a base material 8 to which the piezoelectric speaker 50 is attached.
It is 1.

Sound holes 82, 82 '... For passing a transmitted sound or a received sound are opened in the mounting base material 81.

Further, on the mounting surface 84 of the mounting base material 81 of the handset main body 80, there is provided a fitting projection 83 corresponding to the shape of the opening edge 55 of the pressure transmission sounding body 90 on the storage opening 52 side. It is projected.

In this state, the opening edge 55 of the housing case 51 of the piezoelectric sounding body 90 is fitted to the fitting convex portion 83 on the mounting surface 84, and is crimped and fixed by a screw or an adhesive not shown. As a result, the piezoelectric sounding body 90 is mounted on the mounting base material 81.

At this time, the waterproof sheet 72 stretched along the opening edge 55 closes the entire surface of the opening, and the peripheral portion abutting against the opening edge is mounted on the mounting surface via the rubber ring 26 which is an elastic member. Since the structure is crimped to 34, the sound passage 3
The structure completely prevents the intrusion of water droplets or moisture from the outside through 2, 32 '.

Further, the waterproof sheet 72 does not come into contact with the mounting surface 84 of the mounting base material 81 in the handset main body 80, and a gap corresponding to the thickness of the cross section of the non-air-permeable elastic member (eg, rubber ring) 91 is maintained. Therefore, it is possible to freely vibrate in the gap. Therefore, the sound pressure due to the vibration of the piezoelectric vibrating plate 60 of the piezoelectric sounding body 90 attached to the earpiece is not attenuated by the waterproof sheet 72, and the sound passing holes 82, 82 are directly transmitted by the vibration of the waterproof sheet 72 itself.
´…, and conversely, the sound pressure of the speaker's voice in the transmitter is not greatly attenuated, and the sound passage 82,
Since it is transmitted to the piezoelectric vibrating plate 60 through 82 '..., the sound pressure is less deteriorated.

In order to prevent the sound pressure from deteriorating due to the waterproof measure using the waterproof sheet 72, the waterproof sheet 72 should be sufficiently non-breathable so that the waterproof sheet 72 can freely vibrate. It is desirable to set the thickness of the cross section of the member (for example, rubber ring) 91.

According to the experiment of the present inventor, as shown in the sound pressure-frequency characteristics of FIG. 3, under the same conditions, the conventional piezoelectric sounding body (B) in which the waterproof sheet is attached to the mounting surface is used. The piezoelectric sounding body (A) according to the present invention that can freely vibrate
It can be seen that the sound pressure level of has improved over the entire used frequency band.

[0054]

Since the piezoelectric sounding body according to the present invention is constructed as described above, water droplets and moisture of the external environment are introduced into the storage case from the sound passage hole fitted in the mounting surface of the mounting base material. It has an excellent effect that the intrusion is prevented, the piezoelectric element and the like in the storage case can be protected from the deterioration of reliability due to water and humidity, and the sound pressure is hardly deteriorated by the above-mentioned waterproofing measure.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a mounting structure for a piezoelectric speaker according to the present invention.

FIG. 2 is a sectional view showing a conventional mounting structure for a piezoelectric speaker.

FIG. 3 is a sound pressure-frequency characteristic diagram of a piezoelectric speaker according to the related art and the present invention.

[Explanation of symbols]

 10 Piezoelectric Sounder 51 Storage Case 52 Storage Opening 53 Braking Hole 54 Mounting Step 55 Opening Edge 56 Sealing Adhesive 58 Sound Pressure Adjusting Film 59 Opening Relative Wall 60 Piezoelectric Vibration Plate 61 Piezoelectric Element 62 Vibration Plate 62a Vibration Plate Surface 62b Vibrating plate peripheral part 69 (Waterproof sheet) peripheral part 91 Non-breathable elastic member 72 Waterproof sheet 80 Handset main body 81 Mounting base material 82, 82 '... Sound passage hole 83 Fitting convex portion 84 Mounting surface 90 Piezoelectric speaker

Claims (1)

[Claims] 1. A storage case in which one side is entirely opened and a braking hole is provided in a wall portion facing the opening, and a piezoelectric element is fixed to a surface of a diaphragm, and a peripheral portion of the diaphragm is the storage case. A piezoelectric vibrating plate fixed inside, a waterproof sheet having a peripheral portion attached to an opening edge so as to close the entire opening of the storage case and being capable of freely vibrating, and the attached waterproof sheet. A non-breathable elastic member mounted along the peripheral portion, and a piezoelectric sounding body.