JP2019114958A - Electro-acoustic transducer - Google Patents

Abstract

To provide an electro-acoustic transducer capable of widening a frequency band of sound to be output.SOLUTION: A speaker includes a piezoelectric diaphragm 3A whose outer periphery is fixed and which can be oscillated in accordance with an applied voltage. The piezoelectric diaphragm 3A is divided into multiple cantilevers 10a-10f where outer peripheral sides are allowed to be fixed ends and sides of a specified position P are allowed to be free ends by multiple slits S that are radially extending toward an outer periphery from the specified position P within a main surface 3c. At least two of the multiple cantilevers 10a-10f have mutually different shapes.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electroacoustic transducer.

  Patent Document 1 discloses an electroacoustic transducer including a circular elastic thin plate provided with a hole and a slit, and a circular piezoelectric ceramic plate provided with a hole and a slit having the same shape as the hole and the slit. . The outer periphery of the circular piezoelectric ceramic plate is fixed. Thus, the circular piezoelectric ceramic plate has a configuration in which a plurality of cantilever-shaped diaphragms divided by the slits are radially provided. Therefore, according to this electroacoustic transducer, a large amplitude can be obtained as compared with the conventional piezoelectric diaphragm.

Japanese Patent Application Laid-Open No. 60-186200

  In the electro-acoustic transducer disclosed in Patent Document 1, since the cantilever-like diaphragm has the same shape, the resonance frequency is one point. Therefore, such an electroacoustic transducer has a problem that the frequency band of the sound to be output is relatively narrow.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an electroacoustic transducer which can widen the frequency band of the sound to be output.

In order to achieve the above object, an electroacoustic transducer according to a first aspect of the present invention is
And a piezoelectric diaphragm fixed at its outer periphery and capable of vibrating according to an applied voltage,
The piezoelectric vibrating plate has a plurality of slits extending radially from a specific position in the main surface toward the outer periphery, and the end on the outer peripheral side is a fixed end and the end on the specific position side is a free end Divided into cantilever beams,
Among the plurality of cantilevers, at least two cantilevers have different shapes from one another.

In this case, at least two of the plurality of cantilevers are:
The lengths from the fixed end to the free end are different from each other,
You may do it.

In addition, at least two of the plurality of cantilevers are:
The angles formed by the two outer sides extending from the fixed end to the free end are different from each other,
You may do it.

The piezoelectric diaphragm is configured in a circle,
The plurality of cantilevers are fan-shaped,
You may do it.

The piezoelectric diaphragm includes a flexible substrate and a piezoelectric layer for driving the substrate.
In each of the plurality of cantilevers,
The piezoelectric layer is formed in line symmetry with respect to a virtual line segment equally dividing the cantilever beam through the specific position.
You may do it.

And
A holding member attached to the housing and holding the outer periphery of the piezoelectric diaphragm;
Equipped with
The holding member smoothes the frequency response of the vibration transmitted from the piezoelectric diaphragm to the housing.
You may do it.

  According to the present invention, since a plurality of cantilever beams having different shapes, that is, different resonance frequencies vibrate to generate sound, a peak of the resonance frequency is obtained in a wide band for frequency response of the plurality of cantilevers. By dispersing, the frequency band of the sound to be output can be broadened.

It is a perspective view which shreds a part of speaker concerning Embodiment 1 of the present invention, and shows the composition. It is a top view of the piezoelectric diaphragm of FIG. It is a figure which shows the shape of the piezoelectric layer on the cantilever of the piezoelectric diaphragm of FIG. FIG. 4A is a view showing the internal structure of the cantilever. 4 (B) and 4 (C) are diagrams showing how the cantilever beam vibrates. It is the graph which compared the frequency response of the piezoelectric diaphragm in which the slit is not provided, and the provided piezoelectric diaphragm. FIG. 7 is a top view of a piezoelectric diaphragm according to Embodiment 2 of the present invention. FIG. 7 is a top view of a piezoelectric diaphragm according to a third embodiment of the present invention. It is a figure which shows the modification (the 1) of a piezoelectric diaphragm. It is a figure which shows the modification (the 2) of a piezoelectric diaphragm.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, the same or corresponding components are denoted by the same reference numerals.

Embodiment 1
First, the first embodiment of the present invention will be described.

  As shown in FIG. 1, a speaker 1A as an electroacoustic transducer according to the present embodiment has a cylindrical shape as a whole. The speaker 1A includes a housing 2 as a housing, a piezoelectric diaphragm 3A as a sound source, and a holding member 4 for holding the piezoelectric diaphragm 3A.

  The housing 2 is an insulating member made of resin or the like, and forms the outer shape of the speaker 1A. The housing 2 has a cylindrical internal space 2a inside. The housing 2 amplifies the vibration in the audible band transmitted from the piezoelectric diaphragm 3A to generate a sound.

  As shown in FIG. 2, the piezoelectric diaphragm 3A is formed in a disk shape as a whole. As shown in FIG. 1, the outer peripheral portion 3a of the piezoelectric diaphragm 3A is thicker than the inner peripheral portion 3b. The thickness of the inner circumferential portion 3b is so thin that the portion has flexibility. The outer peripheral portion 3 a is in contact with the holding member 4.

  The holding member 4 is, for example, an annular member made of rubber. The holding member 4 is fitted in a groove provided on the inner wall of the housing 2. An annular groove portion is provided on the annular inner wall portion of the holding member 4, and the outer peripheral portion 3a of the piezoelectric diaphragm 3A is fitted in this groove portion. By such a structure, the holding member 4 holds the piezoelectric diaphragm 3A.

  As shown in FIG. 2, the inner peripheral portion 3b of the piezoelectric diaphragm 3A is circular, and an annular outer peripheral portion 3a is provided on the outer periphery thereof. The inner circumferential portion 3 b and the outer circumferential portion 3 a are provided concentrically.

  In the piezoelectric diaphragm 3A, the inner peripheral portion 3b can vibrate in accordance with the applied voltage. When the piezoelectric diaphragm 3A (inner peripheral portion 3b) vibrates, the vibration is transmitted to the housing 2 through the holding member 4, and the housing 2 amplifies the vibration to generate a sound.

  As shown in FIG. 2, the piezoelectric diaphragm 3A is formed with a plurality of slits S radially extending from the specific position P in the main surface 3c of the inner peripheral portion 3b toward the outer periphery. In the present embodiment, the position P coincides with the center O of the inner circumferential portion 3 b which is a circle.

  The piezoelectric diaphragm 3A is divided into a plurality of cantilever beams 10a to 10f by the slits S. In the plurality of cantilevers 10a to 10f, the end on the outer peripheral portion 3a side is a fixed end, and the end on the specific position P side is a free end.

  In the present embodiment, the shapes of all the cantilevers 10a to 10f are configured to be different from each other. The plurality of cantilevers 10a to 10f are fan-shaped. The plurality of cantilevers 10a to 10f have the same radius but different central angles. In other words, the plurality of cantilevers 10a to 10f have different angles formed by two outer sides extending from the fixed end to the free end.

  The cantilevers 10a to 10f have different resonance frequencies. The resonant frequency increases as the central angle decreases. Therefore, the resonance frequency is increased in the order of the cantilevers 10a, 10b, 10c, 10d, 10e and 10f.

  As shown in FIG. 3, in the plurality of cantilevers 10c, piezoelectric layers 3e are formed in line symmetry with respect to virtual line segments L equally dividing the cantilevers 10c through the specific positions P. The same applies to the piezoelectric layers 3e of the other cantilevers 10a, 10b, 10d to 10f. As a result, the cantilevers 10a to 10f can vibrate faithfully to the vibration of the applied voltage signal without causing twisting or the like on the basis of the fixed end.

  The piezoelectric diaphragm 3A (cantilever beams 10a to 10f) includes a flexible substrate 3d and a piezoelectric layer 3e for driving the substrate 3d, as shown in FIG. The piezoelectric diaphragm 3A (cantilever beams 10a to 10f) is manufactured using a MEMS (Micro Electro Mechanical Systems) technology which is a semiconductor manufacturing technology. An SOI (Silicon On Insulator) substrate is used to manufacture the piezoelectric diaphragm 3A (cantilever beams 10a to 10f). The SOI substrate is a substrate having a laminated structure including a support substrate made of a semiconductor substrate, a BOX layer which is a buried oxide film on the support substrate, and a silicon (SOI) layer which is a semiconductor layer on the BOX layer. , And a wafer including an oxide film.

  For example, as shown in FIG. 4A, the substrate 3d is made of silicon. The lower electrode layer 30a, the piezoelectric material layer 30b, and the upper electrode layer 30c are stacked in this order on the substrate 3d. The lower electrode layer 30a, the piezoelectric material layer 30b, and the upper electrode layer 30c constitute a piezoelectric layer 3e.

  The lower electrode layer 30a and the upper electrode layer 30c are made of a conductive material (for example, a metal such as aluminum or copper). The piezoelectric material layer 30 b is made of, for example, a material (material exhibiting piezoelectric characteristics) such as PZT (lead zirconate titanate). The piezoelectric material layer 30b has a property of expanding and contracting in a longitudinal direction (direction orthogonal to the thickness direction) when a voltage of a predetermined polarity is applied in the thickness direction.

  As shown in FIG. 4B, when a voltage of a polarity (hereinafter referred to as positive polarity) in which the upper electrode layer 30c is positive and the lower electrode layer 30a is negative is applied, the piezoelectric layer 3e extends in the longitudinal direction, Stress is applied to the upper surface side of the substrate 3d in the direction extending in the surface direction. As a result, the cantilever 10a is bent so as to be convex upward, and the free end is displaced downward with respect to the fixed end.

  On the other hand, as shown in FIG. 4C, when a voltage (hereinafter referred to as negative polarity) in which the upper electrode layer 30c is negative and the lower electrode layer 30a is positive, the piezoelectric layer 3e It contracts in the longitudinal direction, and a stress in the contracting direction is applied to the upper surface side of the substrate 3d. As a result, the cantilever 10a is bent so as to be convex downward, and the free end is displaced upward with respect to the fixed end.

  Of course, when a voltage is applied between the two electrode layers so that the upper electrode layer 30c side is positive and the lower electrode layer 30a is negative, it contracts in the longitudinal direction while the upper electrode layer 30c side is negative and the lower electrode layer 30a is positive. As a result, when a voltage is applied between the two electrode layers, a piezoelectric material layer 30b having a property of extending in the longitudinal direction may be used. In this case, when a positive voltage is applied, the cantilever 10a is bent so that the lower side is convex, the free end is displaced upward with respect to the fixed end, and when a negative voltage is applied, the cantilever 10a is bent so that the upper side is convex, and the free end is displaced downward with respect to the fixed end.

  In any case, by applying a voltage of a predetermined polarity between the upper electrode layer 30c and the lower electrode layer 30a, the deformation shown in FIG. 4 (B) or FIG. 4 (C) can be generated. The degree of deformation is an amount corresponding to the applied voltage value. In addition, since the polarization action differs depending on the material constituting the piezoelectric element (for example, depending on the bulk and the thin film), the relationship between the polarity of the voltage and the expansion and contraction may be opposite to the above.

  The cantilevers 10b to 10f operate in the same manner as the cantilever 10a. The cantilevers 10a to 10f may be bent and vibrated by the expansion and contraction of the piezoelectric material layer 30b. In the speaker 1A according to the present embodiment, the same voltage signal is simultaneously supplied to the lower electrode layer 30a and the upper electrode layer 30c of the cantilevers 10a to 10f. Therefore, the cantilevers 10a to 10f synchronously vibrate in accordance with the supplied voltage signal.

  FIG. 5 shows the frequency response of the piezoelectric diaphragm 3A according to the present embodiment. In FIG. 5, the dotted line has the same size as the piezoelectric diaphragm 3A, and shows the frequency response of the piezoelectric diaphragm in which the slit S is not generated. The solid line (thick line) indicates the frequency response of the piezoelectric diaphragm 3A on which the cantilevers 10a to 10f according to the present embodiment are formed. As shown in FIG. 5, in the audible range from 0 Hz to 4000 Hz, the piezoelectric diaphragm 3A in which the cantilevers 10a to 10f are formed has a frequency higher than that of the piezoelectric diaphragm in which the slit S is not formed. The amplitude level (sound pressure (dB)) of the response is increasing.

  Here, in the frequency response of the piezoelectric diaphragm 3A in which the cantilevers 10a to 10f are formed, a plurality of peaks exist. The plurality of peaks are divided into lower band peaks PAa1 to PAf1 and higher band peaks PAa2 to PAf2. Peaks PAa1 to PAf1 on the low band side indicate the frequency response of the primary modes of the cantilevers 10a to 10f, and peaks PAa2 to PAf2 on the high band side indicate the frequency responses of the secondary modes of the cantilevers 10a to 10f. It shows.

  For the low band side peaks, peaks PAa1, PAb1, PAc1, PAd1, PAe1 and PAf1 are assigned in ascending order of frequency. In this case, the peaks PAa1, PAb1, PAc1, PAd1, PAe1, PAf1 correspond to the cantilevers 10a, 10b, 10c, 10d, 10e, 10f, respectively. Further, for the high frequency side peak, the peaks PAa2, PAb2, PAc2, PAd2, PAe2 and PAf2 are assumed to be in ascending order of frequency. In this case, the peaks PAa2, PAb2, PAc2, PAd2, PAe2 and PAf2 correspond to the resonance frequencies of the cantilevers 10a, 10b, 10c, 10d, 10e and 10f, respectively.

  Thus, since the cantilevers 10a, 10b, 10c, 10d, 10e, and 10f have different resonance frequencies, in other words, a plurality of resonance frequencies are generated in a desired frequency band ranging from low to high frequencies. The sound pressure level (dB) of the piezoelectric diaphragm 3A is pushed up in a wide frequency band, and finally the sound pressure level (dB) of the entire audible range is compared with the piezoelectric diaphragm in which the slit S is not formed. Can be raised.

  The holding member 4 smoothes the frequency response of the vibration transmitted from the piezoelectric diaphragm 3A to the housing 2 and transmits the smoothed frequency response to the housing 2. Thereby, the frequency response of the vibration of the housing 2 is equalized in the state where the sound pressure level is high.

Second Embodiment
Next, a second embodiment of the present invention will be described.

  The speaker 1B according to the second embodiment includes a housing 2 as a housing, a piezoelectric diaphragm 3B as a sound source, and a holding member 4 for holding the piezoelectric diaphragm 3B. That is, the present embodiment is different from the first embodiment in that a piezoelectric diaphragm 3B is used instead of the piezoelectric diaphragm 3A.

  The piezoelectric diaphragm 3B is, as shown in FIG. 6, the same as the piezoelectric diaphragm 3A in that a plurality of slits S extending radially from a specific position P in the main surface 3c toward the outer periphery are formed. . However, in the piezoelectric diaphragm 3B, the specific position P is not offset from the center O of the circle but from the center and is eccentric.

  The piezoelectric diaphragm 3B is divided into a plurality of cantilevers 11a, 11b1, 11b2, 11c1, 11c2, 11d1, 11d2, 11e1, 11e2, 11f by the slits S. In the plurality of cantilevers 11a, 11b1, 11b2, 11c1, 11c2, 11d1, 11d2, 11e1, 11e2, 11f, the end on the outer peripheral portion 3a side is the fixed end, and the end on the specific position P is the free end Become.

  Among the plurality of cantilevers 11a to 11f, the lengths and central angles from the fixed end to the free end of each of 11a, 11b1 (11b2), 11c1 (11c2), 11d1 (11d2), 11e1 (11e2), and 11f are mutually different. It is different. Specifically, the length from the fixed end to the free end of the cantilever 11a is the largest, and the length from the fixed end to the free end of the cantilever 11f is the smallest. Also, the length from the fixed end to the free end is shortened in the order of the cantilever 11b1 (11b2), the cantilever 11c1 (11c2), the cantilever 11d1 (11d2), and the cantilever 11e1 (11e2). . The cantilevers having different lengths from the fixed end to the free end have different resonance frequencies. The longer the length from the fixed end to the free end, the lower the resonant frequency.

  The cantilevers 11b1 and 11b2 have the same shape. The same applies to the cantilevers 11c1 and 11c2, the cantilevers 11d1 and 11d2, and the cantilevers 11e1 and 11e2. Cantilever beams having the same shape have the same resonant frequency. By providing a plurality of cantilever beams having the same resonant frequency, the amplitude level (sound pressure) around the resonant frequency can be increased.

  In FIG. 5, the frequency response of the piezoelectric diaphragm 3B on which the cantilevers 11a to 11f according to the present embodiment are formed is indicated by a solid line (thin line). As shown in FIG. 5, in the audible range from 0 Hz to 4000 Hz, the piezoelectric diaphragm 3B in which the cantilevers 11a to 11f are formed is greater than the piezoelectric diaphragm (dotted line) in which the slit S is not generated. The amplitude level (sound pressure (dB)) of the frequency response from 0 Hz to 4000 is increasing.

  A plurality of peaks appear in the frequency response of the piezoelectric diaphragm 3B in which the cantilevers 11a to 11f are formed. The peak PBa1 of the lowest region is due to the vibration of the first-order mode of the cantilever 11a. The peak PBb1 next to it is due to the vibration of the primary mode of the cantilevers 11b1 and 11b2. Hereinafter, the peaks PBc1 of the cantilevers 11c1 and 11c2 and the peaks PBd1 of the cantilevers 11d1 and 11d2 and the peaks of the cantilevers 11e1 and 11e2 in order of decreasing lengths from the fixed end to the free end. The peak PBf1 of the PBe1 and the cantilever 11f is aligned. Further, in the upper band, peaks PBa2, PBb2,... Due to the secondary mode vibration of the respective cantilevers 11a to 11f are arranged.

  Compared to the piezoelectric diaphragm 3A according to the above-described embodiment, in the piezoelectric diaphragm 3B according to this embodiment, the peak frequency is more dispersed, and the frequency response is flat. Therefore, according to the speaker 1B according to the present embodiment, sounds of various frequencies over the entire audible range can be reproduced more uniformly.

Third Embodiment
Next, a third embodiment of the present invention will be described.

  As shown in FIG. 7, a speaker 1C according to the present embodiment includes a housing 2 as a housing, a piezoelectric diaphragm 3C as a sound source, and a holding member 4 for holding the piezoelectric diaphragm 3C. That is, the present embodiment is different from the first embodiment in that the piezoelectric diaphragm 3C is used instead of the piezoelectric diaphragm 3A.

  In the piezoelectric diaphragm 3C, the shape of the cantilever formed by the slit S is different from that of the first embodiment. As shown in FIG. 7, the piezoelectric diaphragm 3 </ b> C is formed with a plurality of slits S radially extending from the specific position P in the main surface 3 c toward the outer periphery. In the present embodiment, the position P is offset not from the center O of the circle but from the center and is eccentric.

  The piezoelectric diaphragm 3C is divided into a plurality of cantilevers 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, 12i, 12j by the slits S. In the plurality of cantilevers 12a, 12b, 12c, 12e, 12f, 12g, 12h, 12i, 12j, the end on the outer peripheral portion 3a side is a fixed end, and the end on the specific position P is a free end Become.

  The plurality of ten cantilevers 12a to 12j have different shapes and different resonance frequencies. As a result, the peak of the resonance frequency can be dispersed in a wider band than the second embodiment.

  As described above in detail, according to each of the above-described embodiments, the plurality of cantilevers 10a to 10f and the like having different shapes, that is, different resonance frequencies, vibrate to generate a sound, so that a plurality of pieces By dispersing the peak of the resonance frequency in a wide band with respect to the frequency response of the holding beams 10a to 10f and the like, the frequency band of the output sound can be broadened.

  Moreover, according to each said embodiment, the length from a fixed end to a free end mutually differs about several cantilever 10a-10f grade | etc.,. In this way, the resonant frequencies of the plurality of cantilevers 10a to 10f and the like can be easily changed. The lengths from the fixed end to the free end of at least two cantilevers of the plurality of cantilevers 10a to 10f and the like may be different from each other. This is because the sound pressure level can be improved because at least two or more peaks can be provided for the frequency response.

  Further, according to each of the above-described embodiments, the angles formed by the two outer sides extending from the fixed end to the free end are mutually different. In this way, the resonant frequencies of the plurality of cantilevers 10a to 10f and the like can be easily changed. In addition, about the at least two cantilever beams among the plurality of cantilever beams 10a to 10f, angles formed by two outer sides extending from the fixed end to the free end may be different from each other. In this way, the frequency response can have at least two or more peaks, and the sound pressure level can be improved.

  Further, according to each of the above-described embodiments, the piezoelectric diaphragms 3A to 3C are formed in a circular shape, and the plurality of cantilevers 10a to 10f and the like are formed in a fan shape. In this way, all the cantilevers 10a to 10f and the like can be arranged in the same circle, so that the whole of the speakers 1A to 1C can be miniaturized.

  As shown in FIG. 8, an elliptical piezoelectric diaphragm 3D may be used as the piezoelectric diaphragm. The piezoelectric diaphragm 3D has slits S radially formed at its center O and a specific position P, and cantilevers 13a1, 13a2, 13a3, 13a4, 13b1, 13b2, 13b3, 13b4, 13c1, 13c2, 13c3, 13c4 Is formed. In this way, even if the slits S are formed so that the central angle is the same from the center O, the length from the fixed end to the free end of each cantilever is changed to make the resonance frequency different. You can do so.

  Further, as shown in FIG. 9, a rectangular piezoelectric diaphragm 3E may be used as the piezoelectric diaphragm. The piezoelectric diaphragm 3E has slits S radially formed at its center O and a specific position P, and cantilevers 14a, 14b1, 14b2, 14c1, 14c2, 14d, 14e1 and 14e2 are formed. In this way, even if the slits S are formed so that the central angle is the same from the center O, the length from the fixed end to the free end of each cantilever is changed to make the resonance frequency different. You can do so. Thus, the piezoelectric diaphragm may have a polygonal shape.

  Further, according to each of the above-described embodiments, the piezoelectric diaphragms 3A, 3B, and 3C include the flexible substrate 3d and the piezoelectric layer 3e for driving the substrate. In each of the plurality of cantilevers 10a to 10f, the piezoelectric layer 3e is formed in line symmetry with respect to an imaginary line segment L equally dividing the cantilevers 10a to 10f and the like through the specific position P. . In this way, it is possible to vibrate faithfully to the applied voltage signal without causing twisting or the like.

  Further, according to the above embodiments, the speakers 1A, 1B, 1C are attached to the housing 2 and the housing 2, and hold the outer peripheral portion 3a of the piezoelectric diaphragms 3A, 3B, 3C, 3D, 3E. And a holding member 4. Further, the holding member 4 smoothes the frequency response of the vibration transmitted from the piezoelectric vibration plates 3A, 3B, 3C, 3D, 3E to the housing 2. In this way, the frequency response of the vibration can be smoothed while the vibration and amplitude of the housing 2 are increased, so that faithful reproduction of the sound according to the sound to be originally reproduced in the audible range is possible. It becomes.

  In the above-described embodiments, weights may be attached to the tips (free ends) of the cantilevers 10a to 10f and the like. In addition, the thicknesses of the cantilevers 10a to 10f may be made different. Even in this case, the respective resonant frequencies can be further dispersed.

  In addition, although the electroacoustic transducers which concern on said each embodiment were the speakers 1A-1C, you may be an ultrasonic wave generator which generates an ultrasonic wave. Moreover, it may be a sensor that receives sound waves and ultrasonic waves and converts them into electric signals.

  The present invention is capable of various embodiments and modifications without departing from the broad spirit and scope of the present invention. In addition, the embodiment described above is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiments but by the claims. And, various modifications applied within the scope of the claims and the meaning of the invention are considered to be within the scope of the present invention.

  The present invention can be applied to a small speaker or the like.

  1A, 1B, 1C Speaker, 2 cases, 2a internal space, 3A, 3B, 3C, 3D, 3E piezoelectric diaphragm, 3a outer peripheral portion, 3b inner peripheral portion, 3c main surface, 3d substrate, 3e piezoelectric layer, 4 holding Members 10a, 10b, 10c, 10e, 10e, 10a, 11b1, 11b2, 11c1, 11c2, 11d1, 11d2, 11e1, 11e2, 11f, 12a, 12b, 12c, 12d, 12e, 12g, 12h, 12h 12i, 12j, 13a1, 13a2, 13a3, 13a1, 13b2, 13b3, 13b1, 13c2, 13c3, 13c4, 14a, 14b1, 14b2, 14c1, 14c2, 14d, 14e1, 14e2 Cantilever, 30a lower electrode Layer, 30b piezoelectric material layer, 30c upper electrode layer, S-slip

Claims (6)

And a piezoelectric diaphragm fixed at its outer periphery and capable of vibrating according to an applied voltage,
The piezoelectric vibrating plate has a plurality of slits extending radially from a specific position in the main surface toward the outer periphery, and the end on the outer peripheral side is a fixed end and the end on the specific position side is a free end Divided into cantilever beams,
Among the plurality of cantilevers, at least two cantilevers have different shapes from each other,
Electro-acoustic transducer. Of the plurality of cantilevers, at least two cantilevers are:
The lengths from the fixed end to the free end are different from each other,
An electroacoustic transducer according to claim 1. Of the plurality of cantilevers, at least two cantilevers are:
The angles formed by the two outer sides extending from the fixed end to the free end are different from each other,
An electroacoustic transducer according to claim 1 or 2. The piezoelectric diaphragm is configured in a circle,
The plurality of cantilevers are fan-shaped,
The electroacoustic transducer according to any one of claims 1 to 3. The piezoelectric diaphragm includes a flexible substrate and a piezoelectric layer for driving the substrate.
In each of the plurality of cantilevers,
The piezoelectric layer is formed in line symmetry with respect to a virtual line segment equally dividing the cantilever beam through the specific position.
The electroacoustic transducer according to any one of claims 1 to 4. And
A holding member attached to the housing and holding the outer periphery of the piezoelectric diaphragm;
Equipped with
The holding member smoothes the frequency response of the vibration transmitted from the piezoelectric diaphragm to the housing.
An electroacoustic transducer according to any one of the preceding claims.

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