JPH087760Y2 - Piezoelectric speaker - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a piezoelectric speaker using a piezoelectric conversion element as a sounding body, and more particularly to a flat plate-shaped piezoelectric speaker having excellent acoustic characteristics.

[Conventional technology]

Conventionally, as in the inventions disclosed in, for example, Japanese Utility Model Publication Nos. Sho 64-13095 and Sho 64-55790, a piezoelectric conversion element is attached to the surface of a flat panel to transmit a visual and auditory transmission effect and induce attention. A flat plate-shaped speaker with improved effect has been proposed.

Alternatively, as in the invention described in Japanese Patent Application Laid-Open No. 54-121112, there has been proposed a speaker in which a plurality of piezoelectric conversion elements are arranged on the same diaphragm.

Since such a flat speaker can simultaneously transmit visual information and auditory audio information drawn on the surface of the speaker and can use a narrow space, it can be used for signs, advertisements, etc. Can be used for.

[Problems to be solved by the device]

However, in a panel-shaped flat panel speaker system that displays signs, advertisements, etc. on its surface, it is necessary to drive at a constant volume and sound pressure in order to improve the effect of attracting attention.

Conventionally, in order to obtain a certain volume, a flat plate material,
A dynamic speaker unit was attached, and an amplifier circuit was attached if necessary. However, in the flat panel type speaker system having this structure, it is difficult to form the speaker as a whole thinly, or only the speaker unit is protruded, which may restrict the installation place.

Therefore, although the inventions as mentioned above have been proposed, in each case, a piezoelectric element is formed on the surface of a plate material such as a photographic panel and the plate material is driven as a vibration plate, or through a vibration plate of the piezoelectric conversion element. The plate itself is vibrating. Therefore, the thickness of the panel-type speaker as a whole can be reduced, but on the other hand, it is necessary to convert the electrostrictive action of the piezoelectric element into a vibration plate over a wide range as acoustic vibration. The pressure was not always sufficient.

Also, regarding the sound quality, in the case of the invention as described above, the characteristics of the piezoelectric conversion element itself, which is the sounding body, have not been improved, and the high frequency range, which is the sound quality peculiar to the speaker using the piezoelectric conversion element, is emphasized There is an unavoidable disadvantage that the low range becomes difficult to hear. Also, the material of the panel that is the diaphragm,
The arrangement and mounting structure of the piezoelectric conversion element also induces unnecessary vibration to affect the sound quality, and its adjustment is difficult.

It is an object of the present invention to provide a panel-shaped piezoelectric speaker that realizes a sound pressure level and acoustic characteristics sufficient for transmitting information.

[Means for solving the problem]

A piezoelectric speaker according to the present invention has a flat plate-shaped first plate member having a plurality of through holes and a second plate member having a hollow portion inside and a hole corresponding to the hole of the first plate member.
And a piezoelectric conversion element in which piezoelectric elements are formed on both surfaces in a through hole selected from a plurality of through holes is sandwiched and held in a gap between the first and second plate materials, and
The back opening of the through hole of the second plate member is closed by a shielding plate, and the back space of the piezoelectric conversion element is closed via the cavity of the second plate member.
It is characterized in that it is led to a through hole in which the piezoelectric conversion element is not installed.

[Action]

In this piezoelectric speaker, as shown in FIG. 2, a piezoelectric transducer element 1 which is a sounding body each having a vibrating plate 8 is installed in a plurality of through holes 4 provided in a flat plate member 2 and fixed. Realizes sound pressure level.

In addition, as shown in FIG. 3, the rear space of the piezoelectric conversion element 1 installed in the through hole 4 is a through hole in which the piezoelectric conversion element 1 is not installed via the cavity 12 of the second plate member 2b. It leads to 4 '. Therefore, since the back space of the piezoelectric conversion element 1 is substantially expanded and the front space is in the open state, the natural vibration form of the piezoelectric conversion element 1 can be promoted and the sound quality can be improved.

In addition, the space from the back space of the piezoelectric conversion element 1 through the cavity 12 of the second plate member 2b and further to the through hole 4 of the first plate member 2a brings about a so-called bass reflex effect, from the low range to the high range. A wide range of acoustic characteristics can be obtained.

As shown in FIG. 4, among the plurality of through holes 4 formed in the flat plate member 2, the piezoelectric conversion element 1 is placed in the through holes 4 selected such that the distances X and Y between them are different from each other. When installed, the sounds emitted from the respective piezoelectric conversion elements 1 do not interfere with each other, and the sound quality can be further improved.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partial sectional perspective view showing a first embodiment of the present invention. FIG. 2 is an exploded perspective view of an essential part showing the mounting structure of the piezoelectric conversion element according to the first embodiment, and FIG.
FIG. 4 is a sectional view taken along the line AA ′ shown in FIG. 1, and FIG. 4 is a front view showing a piezoelectric speaker according to a second embodiment of the present invention. Further, FIG. 5 is an exploded perspective view of an essential part showing a mounted state of the piezoelectric conversion element according to the third embodiment of the present invention.

As shown in FIG. 1, the first plate 2a is formed with the through holes 4 while conforming to the shape and size of the marker portion 11 such as a poster attached to the surface thereof. This through hole 4 is a plate material 2.
A plurality of piezoelectric speakers are formed according to the size of the device and the installation location of the piezoelectric speaker of the present invention. In this example, 9
The individual through holes 4 were formed.

The second plate member 2b is formed to have substantially the same shape and size as the first plate member 2a, and the through hole 4 provided in the first plate member 2a is formed.
A plurality of through holes 4 are provided corresponding to the above.

These first and second plate members 2a and 2b are made of a synthetic resin such as polypropylene, and as shown in FIG. 2, a flat plate having a certain thickness is provided inside a plurality of pipe-shaped cavities by a partition 13. The part 12 is formed.

The piezoelectric conversion element 1 is composed of a disk-shaped vibrating plate 8 also serving as one electrode, and a piezoelectric element 7 formed by laminating ceramics or the like concentrically with the vibrating plate 8 at the center of the front and back surfaces thereof. Then, an electrode 9 made of a conductive metal layer is formed on the surface of the piezoelectric element 7 by a metallizing process, and a lead wire 10 is electrically connected to the front and back electrodes 9 and the diaphragm 8 which is the other electrode. It is connected to the.

The piezoelectric conversion element 1 includes a first plate member 2a and a second plate member 2b.
In the through hole 4 formed in the above, it is held so as to be sandwiched in the gap between the first plate member 2a and the second plate member 2b. In this embodiment, the through holes 4 of the first plate member 2a and the second plate member 2b have different diameters, and a step portion is formed on the inner surface of the through hole 4.
Then, the adhesive 14 is applied to this step portion to apply the piezoelectric conversion element 1
Fixed.

Moreover, the piezoelectric conversion element 1 is installed in the through hole 4 arbitrarily selected from the plurality of through holes 4 formed in the plate material 2. In this embodiment, as shown in FIG. 1, the through holes 4 arranged at both ends are selected from the nine through holes 4, and the piezoelectric conversion element 1 is fixed to the step portion of the through holes 4. .

Furthermore, the rear opening of the through hole 1 formed in the second plate member 2b,
That is, as shown in FIG. 3, the closing plate 5 made of a metal plate or the like is arranged in the opening on the back surface side of the second plate material 2b,
Shields the rear opening, and first and second plate materials
The periphery of 2a and 2b is sealed with a frame 15 such as an adhesive tape to obtain a piezoelectric speaker as shown in FIG.

In the piezoelectric speaker according to this embodiment, the back space of the piezoelectric conversion element 1 installed in the through hole 4 is expanded by the cavity 12 of the second plate member 2b, and the front space is in the open state. The piezoelectric conversion element 1 can vibrate more naturally, and the sound quality is improved.

Further, the back space of the piezoelectric conversion element 1 has the first and second spaces.
Since it communicates with the through hole 4 in which the piezoelectric conversion element 1 is not arranged, that is, the open hole 4 ', through the cavity 12 of the plate materials 2a, 2b, it is possible to obtain a kind of bass reflex effect, and thus the sound quality in the low range Is improved, and a piezoelectric speaker having a wide range of range characteristics can be realized.

In this embodiment, the first plate 2a and the second plate 2a
As for 2b, as shown in FIG. 3, both cavities 12 are bonded so that they are released in the same direction, but they are bonded in different directions, for example, in directions orthogonal to each other or in directions intersecting each other. Good. In this case, the length dimensions of the cavity 12 of the first and second plate members 2a and 2b for obtaining the bassless effect are different, and the frequency characteristics can be adjusted, so that it is more possible depending on the installation location of the piezoelectric speaker. Excellent acoustic characteristics can be obtained.

Next, a second embodiment of the present invention shown in FIG. 4 will be described.

The first and second plate members 2 are, similarly to the first embodiment,
It is a flat plate made of synthetic resin such as polypropylene and has a plurality of pipe-shaped hollow portions formed by partitions inside. Then, as shown in FIG. 4, a plurality of through holes 4 are formed at desired positions, and the piezoelectric conversion element 1 is arranged in the through holes 4 selected from the through holes 4.

In this embodiment, the through holes 4 formed in the first and second plate members 2 are provided substantially on the diagonal line II of the plate member 2 and substantially on the center line III of the plate member 2, as shown in FIG.
Further, the distances X and Y between the through hole 4 on the center line III and the through hole 4 on the diagonal line II adjacent to this through hole are made different.

Then, the piezoelectric conversion element 1 is arranged in the through holes 4 on the diagonal line II of the plate material 2, and the back opening of each through hole 4 is blocked by a closing plate made of metal.

In this embodiment, the back space of the piezoelectric conversion element 1 arranged on the diagonal line II of the plate material 2 together with the adjacent piezoelectric conversion element 1 passes through the cavity of the second plate material 2 and the center line III of the plate material 2. The upper through holes 4 are released to the outside as common releasing holes.

Since the pair of piezoelectric transducers 1 having the through hole 4 on the center line III as a common open hole have different distances to the through holes 4, they interfere with each other due to sound from the front space. Is eliminated and the sound quality is improved.

Next, a third embodiment of the present invention shown in FIG. 5 will be described.

In this embodiment, a first plate member 3a made of a synthetic resin such as expanded polystyrene and a flat plate made of a synthetic resin such as polypropylene, the inside of which is provided with a plurality of pipe-shaped hollow portions formed by partitions. The plate material 3b was attached, a plurality of through holes 4 were provided therein, and the piezoelectric conversion element 1 was placed in the selected through hole 4.

The piezoelectric conversion element 1 is arranged on the step portion on the inner side surface of the through hole 4 formed by making the diameter dimensions of the through hole 4 provided in the first and second plate members 3a and 3b different from each other, as in the first embodiment. Then, it was fixed using an adhesive or the like. Further, a blocking plate made of a hard metal material (not shown) is attached to the rear opening of the through hole 4 provided in the plate material 3.

In this embodiment, since expanded polystyrene having no cavity formed therein is used as the first plate member 3a, the acoustic characteristics in the high frequency range are higher than those in the first and second embodiments. Is improved.

[Effect of device]

As described above, the piezoelectric speaker according to the present invention has a flat plate-shaped first plate member in which a plurality of through holes are formed and a through hole corresponding to the through holes of the first plate member having a hollow portion inside. And a piezoelectric conversion element having piezoelectric elements formed on both sides in a through hole selected from a plurality of through holes is sandwiched in a gap between the first and second plate materials. In addition to holding, the back opening of the through hole of the second plate member is closed with a shielding plate, and the back space of the piezoelectric conversion element is inserted through the cavity of the second plate member without the piezoelectric conversion element being installed. Since it is characterized in that it is led to the holes, it is possible to install a piezoelectric transducer element, which is a sounding body equipped with a vibration plate, respectively, in a plurality of through holes provided in a flat plate material to achieve a certain sound pressure level. In addition to being able to do it, you can attach photos, posters, etc. In making us, it will not be restricted by its location.

Also, the back space of the piezoelectric conversion element installed in the through hole is
The piezoelectric conversion element is opened through the cavity of the second plate member to a through hole in which the piezoelectric conversion element is not installed. Therefore, the back space of the piezoelectric conversion element is substantially expanded, and the front space is in the open state, so that the natural vibration form of the piezoelectric conversion element can be promoted and the sound quality can be improved.

In addition, the space that extends from the back space of the piezoelectric conversion element through the cavity of the second plate material to the through hole of the first plate material provides a bass reflex effect and obtains a wide range of acoustic characteristics from the low range to the high range. Will be able to.

[Brief description of drawings]

FIG. 1 is a partial sectional perspective view showing a first embodiment of the present invention. FIG. 2 is an exploded perspective view of an essential part showing the mounting structure of the piezoelectric conversion element according to the first embodiment, FIG. 3 is a sectional view taken along the line AA ′ shown in FIG. 1, and FIG. FIG. 6 is a front view showing a piezoelectric speaker according to a second embodiment of the invention.
Further, FIG. 5 is an exploded perspective view of an essential part showing a mounted state of the piezoelectric conversion element according to the third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Piezoelectric conversion element, 2, 3 ... Plate material, 4 ... Through hole, 5 ... Closure plate, 7 ... Piezoelectric element, 8 ... Vibrating plate, 9 ... Electrode, 10 ... Lead wire, 11 ... Marking part, 12 ... Cavity part , 13 ... partitioner, 14 ... adhesive, 15 ... frame part.

Claims (1)

[Scope of utility model registration request] 1. A flat plate-shaped first plate member having a plurality of through holes formed therein, and a second plate member having a hollow portion therein and having through holes corresponding to the through holes of the first plate member formed therein. And a piezoelectric conversion element having piezoelectric elements formed on both sides in a through hole selected from a plurality of through holes is sandwiched and held in the gap between the first plate member and the second plate member. The back opening of the through hole of the plate material is closed by a shielding plate, and the back space of the piezoelectric conversion element is led to the through hole where the piezoelectric conversion element is not installed through the cavity of the second plate material. And a piezoelectric speaker.