JP2003304594A - Treble speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tweeter capable of reproducing sound up to an ultrahigh frequency band with a high efficiency and having excellent sound pressure vs. frequency characteristics with less peak dips and excellent directivity. <P>SOLUTION: The tweeter is provided with: a piezoelectric element 1; a frame 2 with a thin flange 2a to fit the piezoelectric element 1 at an outer circumferential part; and a diaphragm 4. A relation of Ld≥Lp×0.4 holds, where Ld is the minor diameter of the diaphragm and Lp is the minor diameter of the moving part of the piezoelectric element. Since the fitting part of the diaphragm is not orthogonal in a vibration mode and the fitting part of the diaphragm exists around the peripheral part of the diaphragm, no vibration mode is suppressed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treble speaker (a tweeter, which reproduces up to a super treble region near 100 kHz).
Super Tweeter).

[0002]

2. Description of the Related Art In recent years, high-definition, ultra-wideband sources such as DVD audio and super audio CD have been supported.
There has been a demand for a speaker to reproduce up to a super high frequency range up to 100 kHz. It is desired to realize a treble speaker capable of reproducing high frequency sound at low cost regardless of a single component or a small stereo.

Here, as a high-frequency speaker, a type in which a diaphragm is driven by a piezoelectric element has been considered for a long time. However, it is generally known that a treble speaker using a piezoelectric element has not only a large peak dip in sound pressure frequency characteristics, but also it is not easy to obtain a sufficient sound pressure level up to an ultra-high range.

Therefore, as a method proposed for improving the peak dip of the frequency characteristic of the high-pitched speaker using the piezoelectric element as a driving source, there is a technique disclosed in Japanese Patent Laid-Open No. 9-215093.

The above technique will be described with reference to FIG. 3 of the publication. 2 is a circular piezoelectric element, and the piezoelectric element 2
Is supported by the frame 3 on all its peripheral portions. The outer peripheral portion 11b of the diaphragm 1 composed of two cylindrical curved surfaces that are arranged adjacent to each other is attached to the frame 3 and is attached to the center line of the piezoelectric element 2 at the attaching portion 11a. . Vibration plate mounting part 11
a is a joining side of two curved surfaces.

With this structure, the diaphragm 1
Since the vibration from the inner peripheral portion to the outer peripheral portion of the piezoelectric element 2 is transmitted to, that is, only the vibration of the piezoelectric element at a specific position is not transmitted, so that the peak dip of the sound pressure frequency characteristic is reduced.

[0007]

However, in the above-mentioned conventional configuration, since the mounting portion 11a of the vibration plate 1 is located on the center line of the piezoelectric element 2, the vibration mode of the piezoelectric element 2 is suppressed and the efficiency is reduced. There was a problem that it did. Since the mounting portion 11a is the joint side of two curved surfaces, that is, the side of the apex of the wedge-shaped cross section, it has a high rigidity in terms of shape, and the suppression of the vibration mode of the piezoelectric element 2 is even more remarkable.

For this reason, if an attempt is made to obtain a certain degree of efficiency, it is not possible to use a material having a high rigidity as the material of the diaphragm 1 for the above reason, so that it is difficult to transmit the vibration to the ultrahigh frequency range and up to 100 kHz. There is also a problem that ultra high frequency reproduction is not possible.

Further, since the diaphragm 1 is composed of a plurality of curved surfaces, there is a problem that the sound waves emitted from the curved surfaces interfere with each other and the directional characteristics deteriorate.

Further, since the diaphragm 1 is composed of a plurality of curved surfaces, there is a problem that manufacturing and assembling are complicated and the cost is high.

The present invention solves the above-mentioned problems of the prior art. It is a low-cost, high-efficiency, highly efficient reproduction to the ultra-high range, and has high sound pressure frequency characteristics with few peak dips and excellent directional characteristics. The purpose is to provide a speaker for use.

[0012]

In order to achieve this object, a treble speaker according to the present invention has a piezoelectric element, a frame having a thin flange for mounting the piezoelectric element on an outer peripheral portion of the piezoelectric element, and a front shape. A vibrating plate having a major axis and a minor axis and having a convex shape in a sound radiating direction, a position on the non-centerline of the surface of the piezoelectric element, and a thin flange of the frame at least in the major axis direction of the vibrating plate When both sides of the peripheral part of are attached and Ld = short diameter of the vibration plate and Lp = short diameter of the movable portion of the piezoelectric element, L
d ≧ Lp × 0.4.

The high frequency speaker of the present invention comprises a diaphragm fixing portion on a thin flange of the frame, and the diaphragm is attached to the diaphragm fixing portion.

Further, the high-frequency speaker of the present invention comprises a front panel and a damping material, the front panel is attached to the diaphragm side of the frame, and the front panel and the thin flange of the frame are provided between the front panel and the frame. It is arranged so that the damping material is sandwiched.

Further, a thick portion thicker than the thickness of the thin flange is provided inside a portion of the thin flange of the frame where the diaphragm is attached, and the diaphragm is attached to the thick portion.

According to the present invention, it is possible to realize a high-frequency speaker capable of reproducing in a very high frequency range with high efficiency at low cost and having excellent sound pressure frequency characteristics with few peak dips and excellent directional characteristics.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A speaker according to the present invention comprises a piezoelectric element composed of a piezoelectric material bonded to a metal substrate, a frame having a thin flange for mounting the piezoelectric element on an outer peripheral portion of the piezoelectric element, and a front shape having a long diameter. A vibrating plate having a short diameter and being convex in the direction of radiating sound; a position on the non-center line of the surface of the piezoelectric element; With both sides attached, Ld = short diameter of the diaphragm, L
p = Ld ≧ L where p is the short diameter of the movable portion of the piezoelectric element
It has a structure of p × 0.4, and it is a low-cost, high-efficiency speaker capable of reproducing up to the ultra-high range, with excellent sound pressure frequency characteristics with few peak dips and excellent directional characteristics. realizable.

Further, the speaker of the present invention comprises at least one diaphragm fixing portion projecting to the diaphragm mounting portion side on the thin flange, and the diaphragm is attached to the diaphragm fixing portion. Thus, excellent sound pressure frequency characteristics with less peak dip can be realized, and workability at the time of attaching the diaphragm in the manufacturing process can be improved.

Further, the speaker of the present invention comprises a front panel and a damping material, the front panel is attached to the diaphragm side of the frame, and the damping material is provided between the front panel and the thin flange of the frame. Since the material is sandwiched, excellent sound pressure frequency characteristics with less peak dip can be realized, and the front panel serves as a vibration guide guide for the diaphragm so that the diaphragm can be touched from the front. This makes it difficult to prevent the diaphragm from being broken.

Further, the speaker of the present invention is configured such that a thick portion thicker than the thickness of the thin flange is provided inside a portion of the thin flange of the frame where the diaphragm is attached, and the diaphragm is attached to the thick portion. It is possible to realize excellent sound pressure frequency characteristics with even less peak dip, and the thick part serves as a guide when mounting the diaphragm, resulting in workability when mounting the diaphragm in the manufacturing process. Can be improved.

The high frequency speaker of the present invention will be described below based on specific embodiments.

(Embodiment 1) FIG. 1 shows the configuration of a treble speaker according to Embodiment 1 of the present invention. In FIG. 1, 1
Is a piezoelectric element, and a thin disk-shaped piezoelectric body 1a is bonded to one surface of a circular metal substrate 1b. That is, the piezoelectric element 1 is a monomorph type. Reference numeral 2 denotes an integrally molded frame having a thin flange 2a inside thereof, and the outer peripheral portion of the piezoelectric element 1 is attached to the thin flange 2a.
Here, there is no step on the surface of the piezoelectric element 1 and the surface of the thin flange 2a, and they have the same height (flush). Reference numeral 4 is a substantially semi-cylindrical diaphragm, and both sides of the peripheral portion in the major axis direction are attached to the piezoelectric element 1 and the surface of the thin flange 2a. Reference numeral 3 denotes a front panel, which is attached to the side of the frame 2 to which the diaphragm is fixed.

Next, the materials and dimensions of the components of this high-pitched speaker will be specifically described. The outer diameter of the piezoelectric element 1 is 22.5 mm. The substrate 1b is made of tin-plated iron, has a diameter of 22.5 mm and a thickness of 0.2 m.
m. The material of the piezoelectric body 1a is ceramic, and the diameter is 15 mm and the thickness is 0.2 mm. Two of these are arranged in the longitudinal direction with respect to the long side direction of the thin flange.
The distance between the centers of the piezoelectric elements is 24 mm. With such a configuration, the vibration area is secured while narrowing the lateral width. Each piezoelectric element 2 is electrically connected in parallel.

The material of the frame 2 and the thin-walled flange 2a is ABS resin, and the outermost peripheral portion of the thin-walled flange portion, that is, the joint with the frame has a long side length of 52 mm and a short side length of 28 mm. is there. The thickness is 0.7 mm
Is. The outer periphery of the frame portion has a long side of 70 mm, a short side of 50 mm, and a thickness of 5 mm. This thin flange 2
The piezoelectric element 1 is attached to the portion a over the entire circumference outside the diameter of 20 mm, and is fixedly supported by a rubber adhesive. Further, there is no step between the surface of the piezoelectric element 1 and the surface of the thin flange 2a,
It is the same height (flush).

The front shape of the diaphragm 4 has a major axis of 42 mm,
The semi-cylindrical shape has a short diameter of 18 mm and a central height of 5 mm. The material of the vibrating plate 4 is a graphite film obtained by subjecting a polyimide film having a thickness of 0.05 mm to a high temperature heat treatment at about 2500 ° C. The diaphragm 4 is attached to the surfaces of both the piezoelectric elements 1 and the thin flange 2a with an epoxy adhesive.

The material of the front panel 3 is ABS resin,
The long side of the outer circumference is 70 mm, the short side has a length of 50 mm, and the thickness is 2 mm. The inner periphery of the front panel is attached to the frame 2 with a rubber adhesive without contacting the diaphragm.

The operation of the high-pitched loudspeaker according to the first embodiment of the present invention thus configured will be described below.

First, FIG. 2 shows a vibration mode of a circularly fixed disk, in other words, a movable portion of a piezoelectric element. This is well known in acoustic vibrations, but in Fig. 2 (a)
Is a first mode (fundamental frequency mode), (b) is a second-order nodal circle mode, (c) is a third-order nodal circle mode, and (d) is a fourth-order nodal circle mode. Each of the figures on the upper side shows the plate viewed from the front, and shows that the hatched portion is displaced in the opposite direction to the other portion. In addition, each of the figures on the lower side shows how the cross section of the plate is displaced.

On the other hand, FIG. 3 shows a conventional technique, that is, the vibration mode of the movable portion of the piezoelectric element in the high-tone speaker disclosed in Japanese Patent Laid-Open No. 9-215093 and the vibration plate on the surface of the piezoelectric element. 3 shows the positional relationship between the mounting portion 11a and the mounting portion 11a. As shown in FIG. 3, in all vibration modes, since the mounting portion 11a is orthogonal to the vibration mode node circle, the node circle vibration mode is suppressed. That is, since the beam is attached to the center of the disc, the disc is constrained and is less likely to vibrate.

FIG. 4 is a vibration mode diagram showing the operation of the high-pitched speaker of this embodiment. Reference numeral 4a is a diaphragm mounting portion. As is apparent from this figure, the diaphragm mounting portion 4a is not orthogonal to the vibration mode node circle, but has a positional relationship along the node circle. Therefore, the vibration mode is not suppressed. Further, since the diaphragm mounting portion 4a is a peripheral portion of the diaphragm 4 and is not a side having high rigidity as described in the conventional technique, the vibration mode is not further suppressed. Therefore, the piezoelectric element 1
Since the vibration mode is not suppressed by attaching the diaphragm 4 to the, high efficiency can be obtained.

For the above reasons, since the diaphragm 4 can be made of a material having a high rigidity, and unlike a diaphragm of a cone type or the like in which the portion for transmitting the vibration is concentrated in the neck portion. Since the vibration is transmitted from the wide part of the peripheral part, it is possible to reproduce up to the super high range.

Further, the vibrating plate mounting portion 4a is the piezoelectric element 1
Since the radial distance from the center point of the piezoelectric element 1 does not become constant over a wide range of the piezoelectric element 1 and the mounting position does not become a specific point or a circle symmetric about the central axis, the vibration plate 4 has a piezoelectric element. Various vibration modes No. 1 are uniformly transmitted, and excellent sound pressure frequency characteristics with less peak dip can be obtained.

Particularly when the shape of the piezoelectric element is circular as in the present embodiment, the vibrating plate mounting portion has a positional relationship so as to include both the node and the antinode of the node mode, so that the piezoelectric element is unique. Even in the vibration mode, that is, the resonance frequency, the peak dip of the sound pressure frequency characteristic is further reduced. In addition, since many circular piezoelectric elements are general-purpose products, it is advantageous in terms of cost.

Further, in the present embodiment, the outer peripheral portion of the piezoelectric element 1 is attached to the thin flange 2a having low rigidity because the outer peripheral portion is thin. Therefore, as compared with the case where the piezoelectric element is directly attached to the frame 2, the peripheral constraint impedance of the piezoelectric element is low, and when the peripheral constraint impedance is high, a vibration mode such as a non-axisymmetric mode that is less likely to occur is more likely to occur. There is. As a result, a large number of vibration modes are generated, the resonance concentration at the specific frequency is further alleviated, and the peak dip of the sound pressure frequency characteristic is further alleviated.

FIG. 5 shows a loudspeaker according to the present embodiment and its diaphragm replaced with a diaphragm according to a conventional technique.
Furthermore, a sound pressure frequency characteristic of a comparative example in which the thin flange is eliminated and the piezoelectric element is directly attached to the frame is shown.

In FIG. 5, the solid line A shows the sound pressure frequency characteristics of the high frequency speaker according to the first embodiment, and the dotted line B shows the sound pressure frequency characteristics of the comparative example. In the treble loudspeaker of this comparative example, two semi-cylindrical curved surface diaphragms that are adjacent and juxtaposed to each other as shown in the prior art are used. The joint between the curved surfaces is attached on the center line of the piezoelectric element. The material of the diaphragm of the comparative example is aluminum, and the outer shape has 4 long sides.
2 mm, the short side is 22.5 mm, and the thickness is 0.0
It is 2 mm.

As is apparent from FIG. 5, the treble speaker according to the present embodiment has a frequency of 100 kHz compared to the comparative example.
It can be seen that a much higher sound pressure level can be obtained up to a super high range exceeding z, and that reproduction can be performed with high efficiency. In addition, the low frequency band is widened.

Further, in the comparative example, since the vibrating plate is composed of a plurality of curved surfaces, sound waves emitted from the curved surfaces interfere with each other and the directional characteristic deteriorates.
In the treble speaker according to the present embodiment, the diaphragm has one curved surface, and good directional characteristics can be obtained.

Here, the sound pressure frequency characteristic of FIG. 5 is 2.4.
A characteristic corresponding to the characteristic at a distance of 1 m from the speaker when 5 V is applied is shown, but since the impedance of the piezoelectric element 1 is very high, the efficiency can be further increased in practical use. For example, when the high-frequency speaker of the present embodiment is driven by using a step-up transformer while adjusting the minimum impedance to several Ω as in a general electrodynamic speaker, an output sound pressure level of about 88 dB is obtained. I was able to get it. That is, it is possible to realize a super tweeter that matches a highly efficient speaker system.

Therefore, as described above, according to the present embodiment, it is possible to reproduce up to an ultra high frequency band with high efficiency at a low cost and to have an excellent sound pressure frequency characteristic with few peak dips and an excellent directional characteristic. A treble speaker can be realized.

By the way, in the present embodiment, the short diameter of the vibrating plate 4, that is, the mounting portion width is 18 mm and the outer diameter of the piezoelectric element 1 is 22.5 mm, but the shorter diameter of the vibrating plate corresponding to the mounting portion width is made smaller. It doesn't matter. However, if the minor axis of the diaphragm becomes too small, the vicinity of the center of the piezoelectric element tends to be constrained, so it is not preferable to make the ratio of the minor axis of the diaphragm to the diameter of the movable portion of the piezoelectric element too small.

When the minor axis of the diaphragm is reduced while the front projected area of the diaphragm is made uniform, Ld = minor axis of the diaphragm, Lp
= Ld is 0.4 of Lp when the diameter of the movable portion of the piezoelectric element is set.
When it is less than twice, the efficiency is lowered by about 3 dB as compared with the case of the present embodiment. In order to secure high efficiency, which is one of the features of the present invention, Ld is preferably 0.4 times or more of Lp. This relationship was the same even if the piezoelectric element and the diaphragm had other shapes.

Although two piezoelectric elements 1 are used in the present embodiment, it goes without saying that similar effects can be obtained even when one piezoelectric element is used.

Further, in this embodiment, the thin flange 2a
However, the outer peripheral portion of the piezoelectric element 1 was supported and fixed by an adhesive, but the piezoelectric element 1 was supported by sandwiching the elastic body, and the whole portion was not fixed, but the part was free. Various support methods are possible, such as When such support is performed, the Q of resonance of the nodal circle vibration mode is lowered, the nodal circle vibration mode becomes non-axisymmetrical, and the peak dip of the sound pressure frequency characteristic is reduced.

A supporting method in which the thin flange 2a supports the central portion of the piezoelectric element 1 and the peripheral portion of the piezoelectric element 1 is free is also conceivable. In this case, the vibration mode is the opposite of the vibration mode described with reference to FIG. 2, that is, the vibration mode is such that the central portion serves as a vibration node and the peripheral portion has a large amplitude. However, even in such a case, the vibration mode is suppressed in the high-tone speaker described in the related art, whereas the vibration mode is not suppressed in the present embodiment.

It is also conceivable to attach an elastic body to the central portion of the piezoelectric element 1 or to support the central portion with the thin flange 2a via the elastic body. By doing so, the Q of the resonance of the vibration mode is lowered, or the vibration mode having the node at the center is excited, so that the peak dip of the sound pressure frequency characteristic is reduced.

Further, although the vibrating plate 4 is attached to the side of the metal substrate 1b of the piezoelectric element 1 in this embodiment, the attaching surface may be on the side of the piezoelectric body 1a. Further, although the piezoelectric element 1 is a monomorph type in the present embodiment, it may be a bimorph type.

Further, although the vibrating plate 4 is made of a graphite film in the present embodiment, it goes without saying that various materials can be used. For example, other materials such as metal, resin, paper, composite of graphite scale and resin, cloth impregnated with resin, and the like.

Needless to say, the present invention is not limited to the examples described above.

(Embodiment 2) Next, the configuration of a high-pitched speaker according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a front view of a frame 2 having a thin flange 2a to which two piezoelectric elements 1 are fixed and a cross-sectional view at a center position in the long side direction. The basic configuration is the same as that of the first embodiment, but this embodiment differs from the first embodiment in that the diaphragm fixing portion 2b having an arch-shaped cross section is provided on the thin flange.

Next, the materials and dimensions of the components of this high-pitched speaker will be specifically described. The material of the diaphragm fixing portion 2b is ABS resin, the width is 2 mm, the wall thickness is 1 mm, and the height from the surface of the thin flange is 5 mm. The arch section curvature is the same as the section curvature of the diaphragm. Further, one thin flange is arranged at the center position in the long side direction, and two thin flanges are arranged at 21 mm positions from the center position in the long side direction. Also, the thin flange 2a and the diaphragm fixing portion 2
b is integral molding.

A diaphragm similar to that described in the first embodiment is attached to the diaphragm fixing portion with a rubber adhesive. Further, on the front surface of the frame 2, a front panel similar to that described in the first embodiment is arranged.

The basic operation and effect of the high-pitched sound speaker of the present embodiment configured as described above are similar to those described in the first embodiment.

In addition to the effect of the first embodiment, in this embodiment, the vibration mode of a specific frequency of the diaphragm is further subdivided by partially constraining the diaphragm, and the peak of the sound pressure frequency characteristic is obtained. The dip can be further reduced.

FIG. 7 shows the sound pressure frequency characteristics of the high frequency speaker according to the present embodiment and the high frequency speaker of the comparative example used in the description of the first embodiment. In FIG. 7, a solid line C shows the sound pressure frequency characteristics of the high-pitched speaker according to the present embodiment, and a dotted line B shows the sound pressure frequency characteristics of the comparative example.

As is apparent from FIG. 7, the treble speaker according to the present embodiment is 100 kHz higher than that of the comparative example.
It can be seen that a much higher sound pressure level can be obtained up to a super high range exceeding z, and that reproduction can be performed with high efficiency. Further, it can be seen that the peak dip near 20 kHz is reduced as compared with the first embodiment. This is due to the effect that the vibration mode of the diaphragm is further subdivided by the diaphragm fixing portion and the number of vibration modes is increased.

Further, in the manufacturing process, the diaphragm fixing portion serves as a guide for fixing the diaphragm to the thin flange, and the workability is greatly improved.

In the present embodiment, the cross section of the diaphragm fixing portion has an arch shape, but it has a substantially semicircular shape in which there is no space between the diaphragm mounting portion on the diaphragm fixing portion and the thin flange. It goes without saying that the same effect can be obtained. Further, it goes without saying that the diaphragm fixing portion is not integrally formed with the thin flange, and the material is not limited to ABS resin, and the same effect can be obtained by using other material such as metal. For example, it is considered that it is possible to further reduce the peak dip by using a material having a high vibration damping effect such as rubber.

In addition, it goes without saying that the present invention is not limited to the examples described above.

(Third Embodiment) Next, the configuration of a high frequency speaker according to a third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a diagram showing an appearance and a cross section of the high-pitched sound speaker according to the embodiment. The basic configuration is similar to that of the high-pitched speaker shown in the first embodiment, except that the shape of the front panel 31 and the damping material 5 are arranged. That is, the front panel 31 has the guide portion 31 in the central opening.
It is different in that it has a, and a damping material is sandwiched between the long side portions of the facing portions of the front panel and the thin flange.

Next, the front panel of this treble speaker,
The material and dimensions of the damping material will be specifically described. The length of the long side of the opening of the front panel is 44 mm and the length of the short side is 14 mm. Further, the front panel guide portion 31a is arranged at the center of the opening in the short side direction without contacting the diaphragm. This guide portion 31a
Is made of ABS resin and is integrally molded with the front panel 31. The guide portion 31a has a substantially triangular prism shape, the thickest portion has a thickness of 1 mm, and the maximum width is 2 mm.

Further, the interval between the thin flange and the facing portion of the front panel is 1 mm, and the damping material is sandwiched in this portion. Here, the damping material is a urethane foam sheet, and the thickness is 2 mm before being sandwiched, that is, in the state of the material.
However, it is sandwiched between the thin flange 2a and the front panel 31 and compressed to 1 mm.

The basic operation and effect of the high-pitched sound speaker of the present embodiment having such a configuration are the same as those described in the first embodiment.

In addition to the effect of the first embodiment, in this embodiment, since the front panel presses the thin flange through the damping material, the vibration of the thin flange is damped and the peak dip is dumped. The peak dip in the sound pressure frequency characteristic can be further reduced.

FIG. 9 shows the sound pressure frequency characteristics of the high-pitched loudspeaker according to the present embodiment and the high-pitched loudspeaker of the comparative example used in the description of the first embodiment. In FIG. 9, a solid line D shows the sound pressure frequency characteristics of the high-pitched speaker according to the present embodiment, and a dotted line B shows the sound pressure frequency characteristics of the comparative example.

Here, as is clear from FIG. 9, the high frequency speaker according to the present embodiment has a higher level than that of the comparative example.
It can be seen that a much higher sound pressure level can be obtained up to an ultra-high frequency range exceeding 00 kHz, and reproduction can be performed with high efficiency. Further, it can be seen that the peak dips near 5 to 20 kHz and around 50 kHz are reduced as compared with the first embodiment. This is because the front panel presses the thin flange through the damping material, so that the vibration of the thin flange is damped and the peak dip is dumped.

Further, the guide portion of the front panel makes it difficult to directly touch the diaphragm, and it is possible to prevent the diaphragm from being broken.

In the present embodiment, the guide portion of the front panel is made of ABS resin and is integrally molded with the front panel. However, the same effect can be obtained by other materials such as metal. Needless to say.

Regarding the mounting position of the damping material, in the present embodiment, the damping material is sandwiched between the long sides of the facing portion of the front panel and the thin flange, but the short sides, Needless to say, similar effects or higher effects can be obtained on both the long side and the short side.

Needless to say, the present invention is not limited to the examples described above.

(Fourth Embodiment) Next, the configuration of a high-pitched speaker according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a front view of a frame 2 having a thin flange 2a to which two piezoelectric elements 1 are fixed and a cross-sectional view at a center position in the long side direction. Although the basic configuration is the same as that of the first embodiment, the present embodiment is different from the first embodiment in that a thick portion 2c is provided inside the diaphragm mounting portion on the thin flange.

Next, the materials and dimensions of the components of this high-pitched speaker will be specifically described. The material of the thick portion 2c is ABS resin, and the short side width of the thin flange surface portion is 18 mm and the wall thickness is 1.7 mm. The long side direction is the same as the long side width 52 mm of the thin flange.

The sectional shape of the thick portion shown in FIG. 10B is the same as the sectional shape of the diaphragm. That is, the diaphragm is formed so as to be attached to the thick portion without deforming the diaphragm.

A vibration plate similar to that described in the first embodiment is attached to the thick portion with a rubber adhesive. In addition, on the front surface of the frame 2, similarly to the first embodiment.
A front panel similar to that described in 1. is located.

The basic operation and effect of the high-pitched sound speaker of the present embodiment configured as described above are the same as those described in the first embodiment.

In addition to the effect of the first embodiment, in the present embodiment, since the thin flange has portions having different thicknesses, the vibration mode of the thin flange portion is subdivided, and the peak dip of the sound pressure frequency characteristic is further reduced. can do.

FIG. 11 shows the sound pressure frequency characteristics of the high frequency speaker according to the present embodiment and the high frequency speaker of the comparative example used in the description of the first embodiment. In FIG. 11, the solid line E
Shows the sound pressure frequency characteristics of the high-pitched speaker according to the present embodiment, and the dotted line B shows the sound pressure frequency characteristics of the comparative example.

As is apparent from FIG. 11, the high frequency speaker according to the present embodiment is 100 k compared to the comparative example.
It can be seen that a much higher sound pressure level can be obtained up to an ultra-high range exceeding Hz, and that the sound can be reproduced with high efficiency. Further, it can be seen that the peak dip around 5 to 15 kHz is somewhat larger than that of the first embodiment, but the peak dip around 40 to 100 kHz is reduced. This is because the thin-walled flange has portions with different thicknesses, so that the vibration modes of the thin-walled flange portion are further subdivided and the number of vibration modes is increased.

Further, in the manufacturing process, the thick portion serves as a guide for fixing the diaphragm to the thin flange, and the workability is greatly improved.

In the present embodiment, the length of the long side of the thick portion is the same as the length of the long side of the thin flange, but it goes without saying that the same effect can be obtained even if it is not necessarily the same. Is.

Further, a shape in which the thick portion is divided, for example,
It goes without saying that a similar effect can be obtained even if the portion between the two piezoelectric elements in the long side direction of the thin flange is thin.

Needless to say, the present invention is not limited to the examples described above.

[0083]

As described above, according to the high-frequency speaker of the present invention, the frame having the piezoelectric element made of the piezoelectric material bonded to the metal substrate and the thin flange for mounting the piezoelectric element on the outer peripheral portion of the piezoelectric element. And a vibration plate whose front shape has a major axis and a minor axis and is convex in the direction of radiating sound, a position on the non-center line of the surface of the piezoelectric element, and the vibration on the thin flange of the frame. At least both sides of the plate in the major axis direction are attached, and L
When d = short diameter of the vibrating plate and Lp = short diameter of the movable portion of the piezoelectric element, Ld ≧ Lp × 0.4.
Since the diaphragm mounting portion is not orthogonal to the vibration mode, and since the diaphragm mounting portion is the peripheral portion of the diaphragm, the vibration mode is not suppressed, and high efficiency is obtained.

From the above, the material of the diaphragm can be made of a material having high rigidity, and the vibration is transmitted from a wide range of the peripheral portion, so that the reproduction can be performed up to the ultra high range. Further, since the vibration plate mounting portion covers a wide range of the piezoelectric element and the mounting position does not become a specific point, various vibration modes of the piezoelectric element are uniformly transmitted to the vibration plate. Further, since the outer peripheral portion of the piezoelectric element is attached to a thin flange with low rigidity due to its thin thickness, the peripheral constraint impedance of the piezoelectric element is lower and the peripheral constraint impedance becomes higher than when the piezoelectric element is directly attached to the frame. It is in a state where vibration modes such as non-axisymmetric mode, which is difficult to occur, are likely to occur. As a result, a large number of vibration modes are generated, the resonance concentration at a specific frequency is further alleviated, and the peak dip of the sound pressure frequency characteristic is further reduced.

Further, since the width of the diaphragm can be narrowed in the horizontal direction on the front side, excellent directional characteristics in the horizontal direction can be obtained. Further, since the diaphragm is one diaphragm having a single curved surface, the diaphragm can be easily molded and attached to the piezoelectric element.

Therefore, it is possible to realize a high-pitched speaker having excellent sound pressure frequency characteristics with few peak dips and excellent directional characteristics, which can be reproduced with high efficiency up to an ultra-high frequency range at low cost.

According to the treble speaker of the present invention,
At least one diaphragm fixing portion protruding toward the diaphragm mounting portion on the thin flange is provided, and by mounting the diaphragm on the diaphragm fixing portion, the diaphragm fixing portion further increases the vibration mode of the diaphragm. It is subdivided, the number of vibration modes increases, and excellent sound pressure frequency characteristics with less peak dip can be realized, and the diaphragm fixing part serves as a guide when fixing the diaphragm to the thin flange in the manufacturing process, It is also possible to obtain the effect of significantly improving the property.

According to the treble speaker of the present invention,
A front panel and a damping material are provided, and the front panel is attached to the diaphragm side of the frame, and the damping material is sandwiched between the front panel and the thin flange of the frame, whereby the thin flange is attached to the front panel. The vibration of the thin flange is dumped, and excellent sound pressure frequency characteristics with less peak dip can be realized, and the front panel serves as a vibration guide for the diaphragm. Therefore, it becomes difficult to touch the diaphragm, and as a result, the effect of preventing the diaphragm from being broken can be obtained.

According to the treble speaker of the present invention,
The thin-walled flange of the frame has a thicker portion thicker than the thickness of the thin-walled flange inside the mounting portion of the diaphragm, and by attaching the diaphragm to the thick-walled portion, the thin-walled flange has a portion with a different thickness. The vibration modes of the flange are further subdivided, and the number of vibration modes increases,
It is possible to realize excellent sound pressure frequency characteristics with even less peak dip, and the thick part serves as a guide when attaching the diaphragm, resulting in an improvement in workability when attaching the diaphragm in the manufacturing process. can get.

As described above, the present invention has extremely great practical value.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a high frequency speaker according to a first embodiment of the present invention.

[Fig.2] Vibration mode diagram of disk

FIG. 3 is a vibration mode diagram of the piezoelectric element.

FIG. 4 is a vibration mode diagram of the piezoelectric element.

FIG. 5 is a sound pressure frequency characteristic diagram showing the effect of the high frequency speaker according to the first embodiment.

FIG. 6 is a diagram showing a part of a configuration of a high frequency speaker according to a second embodiment.

FIG. 7 is a sound pressure frequency characteristic diagram showing the effect of the treble speaker according to the second embodiment.

FIG. 8 is a diagram showing a configuration of a high frequency speaker according to a third embodiment.

FIG. 9 is a sound pressure frequency characteristic diagram showing the effect of the treble speaker according to the third embodiment.

FIG. 10 is a diagram showing a part of the configuration of a high frequency speaker according to a fourth embodiment.

FIG. 11 is a sound pressure frequency characteristic diagram showing the effect of the high frequency speaker according to the fourth embodiment.

[Explanation of symbols]

1 ... Piezoelectric element 1a ... Piezoelectric body 1b ... Metal substrate 11a ... Joining portion 2 ... Frame 2a: Thin flange 2b: Vibration plate fixing part 2c ... Thick wall 3,31 ・ ・ ・ Front panel 31a ... Guide part 4 ... Vibration plate 4a ... Vibration plate mounting part

Claims (4)

[Claims] 1. A piezoelectric element composed of a piezoelectric body bonded to a metal substrate, a frame having a thin flange for mounting the piezoelectric element on an outer peripheral portion of the piezoelectric element, and a front shape having major and minor diameters and radiating sound. And a vibration plate having a convex shape in the direction of the horizontal axis, and a position on the non-center line of the surface of the piezoelectric element and at least both sides of the peripheral part of the vibration plate in the long-axis direction are attached to the thin flange of the frame, and L
A speaker for high sound, wherein Ld ≧ Lp × 0.4, where d = short diameter of the diaphragm and Lp = short diameter of the movable portion of the piezoelectric element. 2. The thin flange is provided with at least one diaphragm fixing portion protruding toward the diaphragm mounting portion, and the diaphragm is attached to the diaphragm fixing portion. The high-frequency speaker according to 1. 3. A front panel and a damping material are provided, and the front panel is attached to the diaphragm side of the frame, and
The high frequency speaker according to claim 1 or 2, wherein the damping material is arranged so as to be sandwiched between the front panel and the thin flange of the frame. 4. A thick-walled portion thicker than the thin-walled flange is provided inside a portion of the thin-flange flange where the diaphragm is attached,
The treble speaker according to claim 1, 2 or 3, wherein a diaphragm is attached to the thick portion.