JP2599264Y2 - Piezoelectric sounding body - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric sounding body, and more particularly, to a piezoelectric sounding body incorporated in a portable electronic device such as a pager, an IC card, and a mobile phone.

[0002]

2. Description of the Related Art In a portable electronic device such as a pager, an IC card, a cellular phone, etc., a piezoelectric sounding body is used as an acoustic element. In such a case, the impact strength of the piezoelectric sounding body becomes a problem.

A conventional example of a piezoelectric sounding body used in a portable electronic device will be described with reference to FIGS.

[0004] The piezoelectric sounding body 30 shown in FIGS.
A support case 11 having an acoustic chamber 12 with an open top,
A plate-like piezoelectric element 14 is provided in the acoustic chamber 12 of the support case 11.
And a piezoelectric vibrating body 13 having a unimorph structure of the piezoelectric element 14 and a diaphragm 15 made of a conductor, and an electrode 16 provided at the center of the bottom surface of the acoustic chamber 12 in the support case 11. I have.

[0005] Both ends of the vibration plate 15 are bent in a U-shape to form electrode portions 15a and 15b, and extend to the bottom surface side through both end surfaces of the support case 11.

FIG. 12 shows a plan view of the support case 11 from which the piezoelectric vibrator 13 has been removed.

[0007] The support case 11 includes the electrode portion 15.
a, 15b corresponding to the notches 11a, 11b, and the projections 17a,
The piezoelectric vibrating body 13 is positioned by inserting holes provided in the electrode portions 15a and 15b into the protrusions 17a and 17b.

[0008]

However, in the case of the above-described piezoelectric sounding body 30, when, for example, a drop impact is applied to the piezoelectric sounding body 20, the piezoelectric element 14 is bent more than its bending strength. As shown in FIG. 13, a crack c occurs in the piezoelectric element 14, and as shown in FIG.
There is a problem that the sounding function of the piezoelectric sounding body 30 is impaired due to peeling off from the piezoelectric sounding body 30.

Accordingly, an object of the present invention is to provide a piezoelectric sounding body which can prevent cracks and partial peeling even when an impact is applied.

[0010]

According to the present invention, a support case having an acoustic chamber is formed, and both ends are supported by the support case .
In a piezoelectric sounding body having a unimorph-structured piezoelectric vibrator arranged so that a plate-shaped piezoelectric element faces the acoustic chamber, the acoustic chamber is provided with a bending prevention member for preventing bending of the piezoelectric element beyond its bending strength. It is a thing.

[0011] At least one bending prevention member is provided on each of one side or both sides of an electrode provided at the center of the bottom surface of the acoustic chamber in the support case.

[0012] The bending prevention member may protrude at least one or more from an opposing surface of a support case which is divided into upper and lower parts to form an acoustic chamber, to a vicinity of an upper surface or a lower surface of a unimorph-structured piezoelectric vibrator disposed in the acoustic room. It is a configuration provided.

[0013]

According to the piezoelectric sounding body having the above-described structure, the acoustic chamber of the support case is provided with the bending prevention member for preventing the bending of the piezoelectric element beyond its bending strength. In addition, even if an external force greater than the bending strength acts on the piezoelectric element, the bending preventing member prevents the piezoelectric element from bending beyond the bending strength, thereby preventing cracking and partial peeling of the piezoelectric element.

By providing at least one bending preventing member on one or both sides of an electrode provided at the center of the bottom surface of the acoustic chamber in the support case, the bending preventing member can bend more than the bending strength of the piezoelectric element. Can be prevented at a plurality of locations, and the occurrence of cracks and partial peeling of the piezoelectric element can be reliably prevented.

[0015] At least one of the bending prevention members is protruded from an opposing surface of a support case, which is divided into upper and lower parts to form an acoustic chamber, from the upper or lower surface of a unimorph-structured piezoelectric vibrator disposed in the acoustic chamber. With this configuration, it is possible to prevent each of the upper and lower surfaces of the piezoelectric vibrator from bending at a bending strength or more, and to reliably prevent cracks and partial peeling of the piezoelectric element.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

The piezoelectric sounding body 1 shown in FIGS. 1 and 2 has an insulating chamber 12 having an acoustic chamber 12 in which the four corners of the end face are formed in the shape of an arc as in the conventional example, and whose upper part is opened to have a circular shape. A piezoelectric vibrator 13 having a unimorph structure of the piezoelectric element 14 and a vibrating plate 15 made of a conductor, wherein the piezoelectric element 14 is disposed so that the plate-shaped piezoelectric element 14 faces the acoustic chamber 12 of the support case 11; The support case 11 includes an electrode 16 provided at the center of the bottom surface of the acoustic chamber 12 and a bending prevention member 2 for preventing the piezoelectric element 14 provided in the acoustic chamber 12 from bending beyond the bending strength.

At both ends of the vibrating plate 15, electrode portions 15a and 15b bent in a U-shape are formed, and a central portion 15c of the vibrating plate 15 is formed in a disk shape. 15a and 15b are arranged so as to be in close contact with the support case 11 and to reach the bottom side through each end face.

FIG. 3 shows a plan view of the support case 11 from which the piezoelectric vibrator 13 has been removed.

The electrode case 15 is provided on the support case 11.
a, 15b corresponding to the notches 11a, 11b, and the projections 17a,
The piezoelectric vibrating body 13 is positioned by inserting holes provided in the electrode portions 15a and 15b into the protrusions 17a and 17b.

As shown in FIG. 3, the bending preventing members 2 are arranged on the both sides of the electrode 16 provided at the center of the bottom surface of the acoustic chamber 12 in the support case 11, and each of the three members on one side are arranged along the electrode 16. It is composed of six bending prevention columns 3.

As shown in FIG. 2, each of the bending prevention columns 3 projects from the bottom surface of the acoustic chamber 12 to the vicinity of the lower surface of the piezoelectric element 14.

Next, the operation of the piezoelectric sounding body 1 will be described with reference to FIG.

According to the piezoelectric sounding body 1, a total of six bending prevention columns 3 constituting the bending prevention member 3 for preventing the bending of the piezoelectric element 14 beyond the bending strength are provided in the acoustic chamber 12 of the support case 11. Since the piezoelectric element 14 is provided with an impact due to a drop or the like, as shown in FIG. The lower surface of the piezoelectric element 14 abuts, and the bending of the piezoelectric element 14 is reliably prevented. As a result, even if an impact due to a drop or the like is applied to the piezoelectric sounding body 1, it is possible to prevent cracks and partial peeling of the piezoelectric element 14.

Each of the bending prevention columns 3 is connected to the electrode 1
Since 6 pieces are arranged in total, 3 pieces on each side along 6,
These bending prevention columns 3 prevent the bending of the piezoelectric element 14 at six locations, thereby reliably preventing cracking and partial peeling of the piezoelectric element 14.

Next, another embodiment of the present invention will be described with reference to FIGS.

The piezoelectric sounding body 1A shown in FIG. 5 and FIG. 6 has a lower support case 21 having a bottom plate 21a and a rectangular cylindrical shape having an open top, and a lower support case 21 covered with an opening of the lower support case 21. , And a piezoelectric element 14 supported by a stepped portion 21b provided on the inner wall of the lower support case 21.
And a piezoelectric vibrating body 13 having a unimorph structure of a vibrating plate 15 made of a conductor, and at least one or more lower bending preventions projecting upward from a bottom plate 21a of the lower support case 21 and facing the upper end near the piezoelectric element 14. A member 24a, at least one or more upper bending prevention members 24b projecting downward from the lower surface of the upper support case 22 and having a lower end facing the vicinity of the diaphragm 15, and a lower side of the upper support case 22 A protrusion 22 protrudes toward the piezoelectric vibrating body 13 and fixes the piezoelectric vibrating body 13 on the step 21b.
a, an element-side electrode portion 25 disposed from one side wall to the bottom of the lower support case 21 as shown in FIGS. 7 to 9, and from the other side wall to the bottom of the lower support case 21. And a diaphragm-side electrode portion 26 disposed therein. The lower bending prevention member 24a and the upper bending prevention member 24b may be provided in only one of them.

The element-side electrode portion 25 is connected to the piezoelectric element 14 by a connection electrode portion 25a led to the acoustic chamber 23 through the thick portion of the lower support case 21 and the inside of the upper support case 22. I have.

The diaphragm-side electrode portion 26 is connected to the diaphragm 15 by a connecting electrode portion 26a led to the acoustic chamber 23 through the thick portion of the lower support case 21 and the interior of the upper support case 22. Connected.

In FIGS. 5, 6, and 8, reference numeral 27 denotes a sound emission hole provided in the lower support case 21 for communicating the acoustic chamber 23 with the outside air.

According to the piezoelectric sounding body 1A having the above structure,
Even when the piezoelectric element 1 is subjected to an impact due to a drop or the like due to a drop or the like, and the piezoelectric element 14 is going to bend more than its bending strength, as shown in FIG.
a, the upper bending preventing member 24b prevents the bending of the piezoelectric element 14 beyond the bending strength on the lower surface and the upper surface, respectively. As a result, cracking and partial peeling of the piezoelectric element 14 can be reliably prevented. it can.

The lower and upper bending prevention members 24a and 24b may be provided in any number.

The present invention is not limited to the embodiment described above, and various modifications are possible within the scope of the invention.

[0034]

According to the present invention described in detail above, with the above-described configuration, even if an external force greater than the bending strength acts on the piezoelectric element, the bending of the piezoelectric element is prevented by the bending preventing member. In addition, it is possible to provide a piezoelectric sounding body that can prevent cracking and partial peeling of the piezoelectric element.

According to the present invention, at least one bending preventing member is provided on one or both sides of the electrode provided at the center of the bottom surface of the acoustic chamber in the support case. It is possible to provide a piezoelectric sounding body that can prevent bending at a plurality of locations and reliably prevent cracking and partial peeling of the piezoelectric element.

Further, according to the present invention, since at least one or more bending preventing members are protruded to the vicinity of the upper surface or the lower surface of the unimorph-structured piezoelectric vibrator, respectively, the upper or lower surface of the piezoelectric vibrator has a bending strength or more. It is possible to provide a piezoelectric sounding body capable of preventing each bending and reliably preventing cracking and partial peeling of the piezoelectric element.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a piezoelectric sounding body of the present invention.

FIG. 2 is a cross-sectional view showing a piezoelectric sounding body of the present embodiment.

FIG. 3 is a plan view of a support case in the piezoelectric sounding body of the present embodiment.

FIG. 4 is a partially enlarged view showing a contact state between a piezoelectric element and a bending prevention member in the piezoelectric sounding body of the present embodiment.

FIG. 5 is a perspective view showing another embodiment of the piezoelectric sounding body of the present invention.

FIG. 6 is a sectional view showing another embodiment of the piezoelectric sounding body of the present invention.

FIG. 7 is a plan view showing another embodiment of the piezoelectric sounding body of the present invention.

FIG. 8 is a front view showing another embodiment of the piezoelectric sounding body of the present invention.

FIG. 9 is a bottom view showing another embodiment of the piezoelectric sounding body of the present invention.

FIG. 10 is a partially enlarged view showing a contact state between a piezoelectric element and a bending prevention member in another embodiment of the piezoelectric sounding body of the present invention.

FIG. 11 is a sectional view showing a conventional piezoelectric sounding body.

FIG. 12 is a plan view of a conventional support case for a piezoelectric sounding body.

FIG. 13 is a partially enlarged view showing a crack generation state of a piezoelectric element in a conventional piezoelectric sounding body.

FIG. 14 is a partially enlarged view showing a partially separated state of a piezoelectric element in a conventional piezoelectric sounding body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1A Piezoelectric sound generator 2 Curve prevention member 3 Curve prevention column 11 Support case 12 Acoustic chamber 13 Piezoelectric vibrator 14 Piezoelectric element 15 Diaphragm 16 Electrode 21 Lower support case 22 Upper support case 24a Lower curve prevention member 24b Upper curve prevention member

Claims (3)

(57) [Scope of request for utility model registration] 1. A piezoelectric sounding body comprising: a support case in which an acoustic chamber is formed; and a unimorph-structured piezoelectric vibrator in which both ends are supported by the support case and a plate-shaped piezoelectric element faces the acoustic chamber. The piezoelectric sounding body according to any one of claims 1 to 3, wherein the acoustic chamber is provided with a bending prevention member for preventing bending of the piezoelectric element beyond its bending strength. 2. The piezoelectric sounding body according to claim 1, wherein at least one or more of the bending preventing members are provided on one or both sides of an electrode provided at the center of the bottom surface of the acoustic chamber in the support case. 3. The at least one bending prevention member projects from an opposing surface of a support case which is divided into upper and lower parts to form an acoustic chamber, to an upper surface or a lower surface of a unimorph-structured piezoelectric vibrator disposed in the acoustic room. The piezoelectric sounding body according to claim 1, wherein the piezoelectric sounding body is provided.