JP2014107747A - Electroacoustic transducer and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroacoustic transducer which is made thin and compact, improves sound quality, and is capable of contributing to improvement of drop impact resistance while having high reliability, and an electronic apparatus.SOLUTION: The electroacoustic transducer comprises: a frame including a through hole; a first metal plate joined to the frame within the through hole; a second metal plate joined to the frame within the through hole, disposed at a predetermined interval from the first metal plate, and including a plurality of notches penetrating the metal plate in a predetermined region; and a laminate which is interposed between the first metal plate and the second metal plate within the through hole, in which piezoelectric films and metal films are alternately laminated, and which includes at least two or more piezoelectric films. The piezoelectric film is formed from a piezoelectric resin material.

Description

  The present invention relates to an electroacoustic transducer and an electronic device.

  In portable electronic devices such as mobile phones and smartphones, development of thin and stylish designs using sound functions such as music playback and hands-free are becoming active. Such a portable electronic device is equipped with an electroacoustic transducer that converts an electrical signal into an acoustic signal as an acoustic function. For electroacoustic transducers, there is a high demand for small and thin and high sound quality, and development of electroacoustic transducers that are thin and capable of reproducing high-quality sound is required. In a general portable electronic device, an electrodynamic electroacoustic transducer using an electrodynamic speaker using a magnetic circuit is used as an electroacoustic transducer.

JP 2012-110018 A JP 2006-5800 A JP 2004-364334 A JP 2003-23696 A

  The following analysis is given by the inventor.

  However, in an electrodynamic electroacoustic transducer, since the sound pressure level of an electrodynamic speaker using a magnetic circuit depends on the volume exclusion amount, there is a limit to the reduction in thickness and volume in principle. In other words, it is necessary to increase the amount of vibration amplitude to reproduce a large volume, but in electrodynamic electroacoustic transducers, the magnetic pressure becomes a factor when considering the driving force of the magnetic circuit, so the sound pressure level is reduced. In order to increase the volume, there is a trade-off problem that the volume of the magnet cannot be reduced, and if the increase in sound pressure level is pursued, the reduction in thickness must be sacrificed. In addition, when pursuing thinning of an electrodynamic electroacoustic transducer, it is necessary to make the voice coil thin in the magnetic circuit in addition to thinning the magnet. When pursuing thinning of the voice coil, there is a problem such as burning in a magnetic circuit through which a large current flows. For this reason, the electrodynamic electroacoustic transducer is not suitable for thinness from the viewpoint of the volume of the magnet and the reliability of the voice coil.

  Therefore, there is a piezoelectric electroacoustic transducer as a thin electroacoustic transducer that replaces the electrodynamic electroacoustic transducer. Piezoelectric electroacoustic transducers are electroacoustic transducers that generate vibration amplitude using the electrostrictive effect of piezoelectricity. In the piezoelectric electroacoustic transducer, the piezoelectric element itself is a vibration source, which is advantageous for thinning. On the other hand, problems with piezoelectric electroacoustic transducers include high mechanical quality factor (Q) and drop stability.

  In a piezoelectric electroacoustic transducer, a piezoelectric ceramic element is usually used as a piezoelectric element (see, for example, Patent Documents 1 to 4). Since the piezoelectric ceramic element has a high mechanical quality factor Q, a large sound pressure level is obtained near the resonance frequency, but the sound pressure level is attenuated in other bands. That is, in the piezoelectric ceramic element, a valley occurs in the sound pressure frequency characteristic, and the flat sound pressure frequency characteristic, which is an essential design factor for improving the sound quality, deteriorates.

  In addition, since the piezoelectric ceramic element has high rigidity, reproduction at a low sound pressure level is disadvantageous. To reproduce low-frequency sound pressure, it is necessary to reduce the fundamental resonance frequency of the vibrator itself. When using ceramics with high rigidity such as piezoelectric ceramic elements, measures such as expanding the shape of the ceramics are required. is there. Therefore, although the piezoelectric ceramic element is thinner than the piezoelectric type electroacoustic transducer, the projected area is enlarged, so that it is not necessarily advantageous in downsizing.

  Furthermore, since the piezoelectric ceramic element is a brittle material, when stress concentrates on a specific location, breakage such as cracking or chipping occurs. For this reason, portable electronic devices are required to have high drop impact resistance, and thus mounting a piezoelectric electroacoustic transducer using a piezoelectric ceramic element is problematic from the viewpoint of practicality.

  For this reason, in the piezoelectric electroacoustic transducer, an innovative measure capable of improving the drop impact resistance while being thin, small, high sound quality and high reliability has been required.

  The main subject of this invention is providing the electroacoustic transducer and electronic device which can contribute to improving drop impact resistance, having thinness, small size, high sound quality, and high reliability.

  According to a first aspect of the present invention, in the electroacoustic transducer, a frame having a through hole, a first metal plate bonded to the frame in the through hole, and the frame bonded to the frame in the through hole. And a second metal plate having a plurality of notches penetrating in a predetermined region from the first metal plate, the first metal plate and the second in the through hole. A laminate having piezoelectric films and metal films alternately stacked and having at least two piezoelectric films, the piezoelectric film being made of a piezoelectric resin material. Features.

  In a second aspect of the present invention, the electroacoustic transducer is mounted in an electronic device.

  ADVANTAGE OF THE INVENTION According to this invention, the electroacoustic transducer and electronic device which can contribute to improving drop impact resistance, having thinness, small size, high sound quality, and high reliability can be provided.

It is sectional drawing between XX 'of FIG. 2 which showed typically the structure of the electroacoustic transducer which concerns on Embodiment 1 of this invention. It is the expansion | deployment perspective view which showed typically the structure of the electroacoustic transducer which concerns on Embodiment 1 of this invention. It is sectional drawing which showed typically the structure of the electroacoustic transducer which concerns on a comparative example. It is the figure which showed typically the frequency sound pressure characteristic of the electroacoustic transducer which concerns on Embodiment 1 of this invention. It is the figure which showed typically the frequency sound pressure characteristic in the ultrasonic band of the electroacoustic transducer which concerns on Embodiment 1 of this invention. It is sectional drawing which showed typically the structure of the electroacoustic transducer which concerns on Embodiment 2 of this invention. It is the (A) top view which showed typically the structure of the electroacoustic transducer which concerns on Embodiment 3 of this invention, (B) It is sectional drawing between YY '.

[Embodiment 1]
An electroacoustic transducer according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view taken along the line XX ′ in FIG. 2 schematically showing the configuration of the electroacoustic transducer according to Embodiment 1 of the present invention. FIG. 2 is a developed perspective view schematically showing the configuration of the electroacoustic transducer according to Embodiment 1 of the present invention.

  The electroacoustic transducer 1 is a piezoelectric electroacoustic transducer that generates vibration amplitude using the electrostrictive effect of piezoelectricity (see FIGS. 1 and 2). The electroacoustic transducer 1 is mounted on a portable electronic device such as a mobile phone or a smartphone, for example. In the electroacoustic transducer 1, the metal plate 17 and the metal plate 11 are mounted in the through hole 10a of the frame 10 at a predetermined interval, and between the metal plate 17 and the metal plate 11 in the through hole 10a. Piezoelectric films 16, 14, 12 and metal films 15, 13 are alternately laminated, and a laminate 2 having at least two piezoelectric films (three layers in FIG. 1) is interposed. The electroacoustic transducer 1 includes, as main components, a metal plate 11, a piezoelectric film 12, a metal film 13, a piezoelectric film 14, a metal film 15, a piezoelectric film 16, a metal plate 17, and a lead wire. 18a, 18b, 18c, 18d.

  The frame 10 is a member that holds end portions (peripheral portions may be acceptable) of the metal plates 11 and 17. The frame 10 is formed in an annular shape when viewed from above (upper side in FIG. 1; above the plate surface of the metal plate 11), and has a through hole 10a penetrating the frame 10 at the center. The through-hole 10a is formed in a circular shape (may be elliptical) as viewed from above. The frame 10 is joined to the outer peripheral end portion of the metal plate 17 on the inner wall surface in the through-hole 10a (adhesion, press-fitting, etc. are possible). The frame 10 is joined to the outer peripheral end portion of each convex portion 11a of the metal plate 11 spaced from the metal plate 17 on the inner wall surface in the through-hole 10a (adhesion, press-fitting, etc. are also possible). For the frame 10, for example, a resin material, brass, stainless steel, or the like can be used.

  The metal plate 11 is a plate-like member made of metal. The metal plate 11 is formed in a circular shape (may be an oval shape) as viewed from above except for the convex portion 11a. The metal plate 11 has a plurality of convex portions 11a extending outward from the outer peripheral end portion. The metal plate 11 is joined to the inner wall surface of the through-hole 10a of the frame 10 at the outer peripheral end portion of the convex portion 11a (adhesion, press-fitting or the like is also possible). The metal plate 11 is joined to the frame 10 so as to be insulated from the frame 10 when a conductive material is used for the frame 10. The metal plate 11 is joined (adhered or the like) to the piezoelectric film 12 on the surface on the metal plate 17 side. The metal plate 11 has a notch portion 11b in which a part of the metal plate 11 is notched between the convex portions 11a. The cutout portion 11 b becomes a sound hole and is formed in a region that does not overlap the piezoelectric film 12. The metal plate 11 is a support member that supports the laminated body 2 in which the piezoelectric films 16, 14, and 12 and the metal films 15 and 13 are alternately laminated, and at the same time, since the electric conduction is possible, the electrode of the piezoelectric film 12 Can also be used. The metal plate 11 is electrically connected to the lead wire 18 a and has a role of applying an electric signal from the lead wire 18 a to the piezoelectric film 12. The metal plate 11 is made of a metal material (including a metal material such as an alloy) that has conductivity and functions as a vibration plate. For example, phosphor bronze, a stainless material, or the like can be used. The thickness of the metal plate 11 is not particularly limited, but is preferably thinner than the thickness of the piezoelectric film 12 in order to relax the constraint on the piezoelectric film 12.

  The piezoelectric film 12 is a film made of a piezoelectric material interposed between the metal plate 11 and the metal film 13. The piezoelectric film 12 is joined to the metal plate 11 and the metal film 13 (adhesion, bonding, etc. are also possible). The piezoelectric film 12 is formed in a circular shape (may be an oval shape) when viewed from above. The piezoelectric film 12 is separated from the inner wall surface of the through hole 10 a of the frame 10. When an electric signal is applied to the metal plate 11 and the metal film 13, the piezoelectric film 12 generates vibration due to an electrostrictive effect, generates an amplitude motion, and emits a sound wave. The piezoelectric film 12 is made of a piezoelectric resin material having a rigidity lower than that of piezoelectric ceramics and having a drop impact resistance. ) Can be used. The thickness of the piezoelectric film 12 is preferably in the range of 50 μm or more and 500 μm or less. When the thickness is less than 50 μm, a sufficient piezoelectric effect cannot be obtained. When the thickness exceeds 500 μm, the rigidity of the piezoelectric film increases and the vibration amplitude is attenuated. When the piezoelectric film 12 is a unit with a metal film (similar to the metal film 13), a metal film may be present between the piezoelectric film 12 and the metal plate 11.

  The metal film 13 is a film-like member made of metal interposed between the piezoelectric film 12 and the piezoelectric film 14. The metal film 13 is bonded to the piezoelectric film 12 and the piezoelectric film 14 (adhesion, bonding, or the like is also possible). The metal film 13 is formed in a circular shape (or oval shape) when viewed from above. The metal film 13 is separated from the inner wall surface of the through hole 10 a of the frame 10. Since the metal film 13 can conduct electricity, it can also be used as an electrode for the piezoelectric films 12 and 14. The metal film 13 is electrically connected to the lead wire 18 b and has a role of applying an electric signal from the lead wire 18 b to the piezoelectric films 12 and 14. For the metal film 13, a conductive metal material (including a metal material such as an alloy) is used. For example, a silver foil can be used, and phosphor bronze, stainless material, etc., similar to the material of the metal plate 11 can be used. Can be used. The thickness of the metal film 13 is not particularly limited, but is preferably thinner than the thickness of the piezoelectric films 12, 14, 16 in order to relax the constraint on the piezoelectric films 12, 14, 16. The metal film 13 may have a configuration in which two metal films are bonded together.

  The piezoelectric film 14 is a film made of a piezoelectric body interposed between the metal film 13 and the metal film 15. The piezoelectric film 14 is bonded to the metal film 13 and the metal film 15 (adhesion, bonding, or the like is also possible). The piezoelectric film 14 is formed in a circular shape (may be an oval shape) when viewed from above. The piezoelectric film 14 is separated from the inner wall surface of the through hole 10 a of the frame 10. When an electric signal is applied to the metal film 13 and the metal film 15, the piezoelectric film 14 generates vibration due to an electrostrictive effect, generates an amplitude motion, and emits a sound wave. The material and thickness of the piezoelectric film 14 are the same as the material and thickness of the piezoelectric film 12.

  The metal film 15 is a film-like member made of metal interposed between the piezoelectric film 14 and the piezoelectric film 16. The metal film 15 is bonded to the piezoelectric film 14 and the piezoelectric film 16 (adhesion, bonding, or the like is also possible). The metal film 15 is formed in a circular shape (may be elliptical) as viewed from above. The metal film 15 is separated from the inner wall surface of the through hole 10 a of the frame 10. Since the metal film 15 can conduct electricity, it can also be used as an electrode for the piezoelectric films 14 and 16. The metal film 15 is electrically connected to the lead wire 18 c and has a role of applying an electric signal from the lead wire 18 c to the piezoelectric films 14 and 16. The material and thickness of the metal film 15 are the same as the material and thickness of the metal film 13. The metal film 15 may have a configuration in which two metal films are bonded together.

  The piezoelectric film 16 is a film made of a piezoelectric body interposed between the metal film 15 and the metal plate 17. The piezoelectric film 16 is joined (adhered or bonded) to the metal film 15 and the metal plate 17. The piezoelectric film 16 is formed in a circular shape (may be elliptical) as viewed from above. The piezoelectric film 16 is separated from the inner wall surface of the through hole 10 a of the frame 10. When an electric signal is applied to the metal film 15 and the metal plate 17, the piezoelectric film 16 generates vibration due to the electrostrictive effect, generates an amplitude motion, and emits a sound wave. The material and thickness of the piezoelectric film 16 are the same as the material and thickness of the piezoelectric film 12. When the piezoelectric film 16 is a unit with a metal film (similar to the metal film 15), there may be a metal film between the piezoelectric film 16 and the metal plate 17.

  The metal plate 17 is a plate-like member made of metal. The metal plate 17 is formed in a circular shape (or oval shape) as viewed from above. The metal plate 17 is joined to the inner wall surface of the through-hole 10a of the frame 10 (adhesion, press-fitting, or the like is possible) on the entire circumference of the outer peripheral end portion. The metal plate 17 is joined to the frame 10 so as to be insulated from the frame 10 when a conductive material is used for the frame 10. The metal plate 17 is joined (adhered or the like) to the piezoelectric film 16 on the surface on the metal plate 11 side. The metal plate 17 is a support member that supports the laminated body 2 in which the piezoelectric films 16, 14, and 12 and the metal films 15 and 13 are alternately laminated, and at the same time, is capable of electrical conduction. Can also be used. The metal plate 17 is electrically connected to the lead wire 18d, and has a role of applying an electric signal from the lead wire 18d to the piezoelectric film 16. The material and thickness of the metal plate 17 are the same as the material and thickness of the metal plate 11.

  The lead wires 18 a, 18 b, 18 c, and 18 d are wirings for supplying electrical signals to the corresponding metal plate 11, metal film 13, metal film 15, and metal plate 17. The lead wires 18a, 18b, 18c, and 18d are electrically connected to a controller, an amplifier circuit, and the like. For the lead wires 18a, 18b, 18c, and 18d, not only a conductive wire (eg, copper wire) but also a metal foil (eg, copper foil) may be used.

  The above electroacoustic transducer 1 has a metal plate 11, a piezoelectric film 12, a metal film 13, a piezoelectric film 14, a metal film 15, a piezoelectric film 16, and a metal plate 17 that are formed in a predetermined shape in advance. It can manufacture by laminating | stacking and mounting these laminated bodies 2 in the through-opening 10a of the flame | frame 10. FIG.

  Next, the frequency sound pressure characteristics of the electroacoustic transducer according to Embodiment 1 of the present invention will be described with reference to the drawings while comparing with a comparative example. FIG. 3 is a cross-sectional view schematically showing a configuration of an electroacoustic transducer according to a comparative example. FIG. 4 is a diagram schematically illustrating frequency sound pressure characteristics of the electroacoustic transducer according to Embodiment 1 of the present invention. FIG. 5 is a diagram schematically showing frequency sound pressure characteristics in the ultrasonic band of the electroacoustic transducer according to Embodiment 1 of the present invention.

  First, the configuration of the electroacoustic transducer 101 according to the comparative example will be described. Referring to FIG. 3, an electroacoustic transducer 101 according to a comparative example includes a metal plate (11 in FIG. 1), a piezoelectric film (12 in FIG. 1), a metal film (13 in FIG. 1), and a piezoelectric film. (14 in FIG. 1) is eliminated, and in the electroacoustic transducer 101, the piezoelectric body is only one layer of the piezoelectric film 16.

  Referring to the frequency sound pressure characteristic (showing the sound demodulated as a parametric speaker) in FIG. 4, the electroacoustic transducer according to the comparative example (101 in FIG. 3) has a peak sound frequency characteristic. On the other hand, in the electroacoustic transducer according to the first embodiment (1 in FIG. 1), the frequency sound pressure characteristic is flat.

  Referring to the frequency sound pressure characteristics in the ultrasonic band of FIG. 5, in the first embodiment, the sound pressure level is high at a specific frequency in the ultrasonic band, which is suitable as a vibrator (ultrasonic vibrator) of a parametric speaker. . That is, the first embodiment is suitable for oscillating ultrasonic waves of 20000 Hz (20 kHz) or higher. On the other hand, in the comparative example, the sound pressure level is lower than that in the first embodiment at a specific frequency in the ultrasonic band, and is not suitable as a vibrator of a parametric speaker.

  According to the first embodiment, it is possible to contribute to improving the drop impact resistance while being thin, small, high sound quality and high reliability. Detailed effects of the first embodiment are as follows.

  According to the first embodiment, since the piezoelectric film 12, 14, 16 and the metal films 13, 15 are alternately stacked, it can be reproduced with high efficiency and large volume. That is, taking advantage of the thickness advantage of the piezoelectric films 12, 14, and 16 to form a laminated structure in which the piezoelectric films 12, 14, and 16 and the metal films 13 and 15 are alternately laminated, the vibration amplitude is increased. Therefore, it is possible to reproduce a high sound pressure level and sound quality.

  Moreover, according to Embodiment 1, since the piezoelectric films 12, 14, and 16 are comprised from an organic piezoelectric material (resin material), rigidity is low and a fundamental resonant frequency can be reduced.

  In addition, according to the first embodiment, there is an advantage that the thickness of the metal films 13 and 15 or the metal plates 11 and 17 can be easily adjusted to a desired resonance frequency.

  Moreover, according to Embodiment 1, since the piezoelectric films 12, 14, and 16 are organic piezoelectric materials (resin materials), internal loss is high compared with ceramics, and a mechanical quality factor can be reduced.

  Moreover, according to Embodiment 1, since the piezoelectric films 12, 14, and 16 which are rich in flexibility are used as a driving source, the drop impact resistance can be improved. That is, since the impact at the time of dropping can be absorbed by the piezoelectric films 12, 14, and 16 which are organic piezoelectric materials (resin materials), the stability at the time of dropping is improved.

  Further, according to the first embodiment, an FM (Frequency Modulation) or AM (amplitude modulation) modulated ultrasonic wave is oscillated, and a modulated wave is demodulated using an air nonlinear state (dense / dense state) to generate an audible sound. Sound reproduction based on the principle of so-called parametric speaker that reproduces can be used to propagate sound waves using the high directivity that is characteristic of ultrasonic waves, and it is possible to realize a privacy sound source that only the user can hear It becomes. Since the first embodiment is also useful as a highly efficient ultrasonic transducer, it can be applied to a transducer of a parametric speaker. Therefore, the application range is wide and the industrial value is great.

  As described above, since the electroacoustic transducer according to Embodiment 1 has a large amplitude, a low mechanical quality factor, a low fundamental resonance frequency, and a drop impact resistance, it is small and thin and can reproduce high-quality sound. It is.

[Embodiment 2]
An electroacoustic transducer according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 6 is a cross-sectional view schematically showing the configuration of the electroacoustic transducer according to Embodiment 2 of the present invention.

  The second embodiment is a modification of the first embodiment, and the shape of the frame 10 viewed from above the through hole 10a (upper side in FIG. 6) is rectangular, and accordingly, the metal plate 11, the piezoelectric film 12, The metal film 13, the piezoelectric film 14, the metal film 15, the piezoelectric film 16, and the shape of the metal plate 17 viewed from above are rectangular. The convex portion 11a of the metal plate 11 is configured to extend outward from an end portion of an intermediate (center) portion of each side of the rectangular main body portion. In addition, the convex part 11a is good also as a structure extended outside from the edge part of each corner | angular part of a rectangular main-body part. Other configurations are the same as those of the first embodiment.

  According to the second embodiment, the same effects as those of the first embodiment are obtained.

[Embodiment 3]
An electroacoustic transducer according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 7: is the (A) top view which showed the structure of the electroacoustic transducer based on Embodiment 3 of this invention typically, (B) It is sectional drawing between YY '.

  The third embodiment is a modification of the first embodiment, and a plurality of rectangular through holes 10a arranged in a predetermined direction in the frame 10 are provided, and each of the through holes 10a has a rectangular metal plate 11 and a piezoelectric film. 12, a laminate 2 of a metal film 13, a piezoelectric film 14, a metal film 15, a piezoelectric film 16, and a metal plate 17 is provided to form an array structure. The metal plate 11 is joined to the inner wall surface of the through-hole 10a of the frame 10 (adhesion, press-fitting, or the like is possible) on the entire circumference of the outer peripheral end portion. The metal plate 11 is provided with a plurality of notches 11c serving as sound holes. The notch 11 c is formed in the middle (center) of the peripheral edge of each side of the rectangular metal plate 11. Although the notch 11c is not connected to the outer peripheral end face of the metal plate 11 in FIG. 7 but is a through hole, it may be connected to the outer peripheral end face. The distance between adjacent notches 11c (center portion) is preferably within a quarter wavelength of the ultrasonic wave (frequency) to be oscillated in order to prevent interference between sound waves. If the distance between the adjacent notches 11c (center portion) is ¼ wavelength, the notches 11c may not be provided at the peripheral edge of each side of the metal plate 11. Other configurations are the same as those of the first embodiment.

  According to the third embodiment, the same effects as those of the first embodiment can be obtained, and the radiation efficiency of ultrasonic waves can be improved as compared with the first embodiment by using an array structure.

  Note that, in the present application, where reference numerals are attached to the drawings, these are only for the purpose of helping understanding, and are not intended to be limited to the illustrated embodiments.

  Further, within the scope of the entire disclosure (including claims and drawings) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are included within the scope of the claims of the present invention. Is possible. That is, the present invention naturally includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the drawings, and the technical idea.

(Appendix)
According to a first aspect of the present invention, in the electroacoustic transducer, a frame having a through hole, a first metal plate bonded to the frame in the through hole, and the frame bonded to the frame in the through hole. And a second metal plate having a plurality of notches penetrating in a predetermined region from the first metal plate, the first metal plate and the second in the through hole. A laminate having piezoelectric films and metal films alternately stacked and having at least two piezoelectric films, the piezoelectric film being made of a piezoelectric resin material. Features.

  In the electroacoustic transducer of the present invention, it is preferable that each of the first metal plate, the second metal plate, and the metal film is thinner than the piezoelectric film.

  In the electroacoustic transducer of the present invention, the piezoelectric film preferably has a thickness of 50 μm or more and 500 μm or less.

  In the electroacoustic transducer according to the aspect of the invention, it is preferable that the through hole is formed in a circular shape or a rectangular shape when viewed from above the plate surface of the second metal plate.

  In the electroacoustic transducer of the present invention, a plurality of the through holes are formed side by side in a predetermined direction in the frame, and the first metal plate, the second metal plate, and the laminate are arranged in each through hole. It is preferable that

  In the electroacoustic transducer according to the present invention, an end portion of the first metal plate is joined to the frame over the entire circumference, and the second metal plate extends outward between the adjacent cutout portions. It has a convex part, and it is preferable that the edge part of the said convex part is joined to the said flame | frame.

  In the electroacoustic transducer of the present invention, an end of the first metal plate is joined to the frame over the entire circumference, and an end of the second metal plate is joined to the frame over the entire circumference. Preferably, the cutout portion is formed so as not to include an end portion of the second metal plate.

  In the electroacoustic transducer according to the aspect of the invention, the stacked body is disposed away from the frame, and the notch is formed in a region other than the region where the stacked body is disposed in the second metal plate. Is preferred.

  In the electroacoustic transducer of the present invention, it is preferable that each of the first metal plate, the second metal plate, and the metal film is electrically connected to a corresponding lead wire.

  According to a second aspect of the present invention, in the electronic device, the electroacoustic transducer is mounted.

DESCRIPTION OF SYMBOLS 1,101 Electroacoustic transducer 2 Laminated body 10 Frame 10a Through-hole 11 Metal plate (2nd metal plate)
11a Convex part 11b Notch part 11c Notch part 12 Piezoelectric film 13 Metal film 14 Piezoelectric film 15 Metal film 16 Piezoelectric film 17 Metal plate (first metal plate)
18a, 18b, 18c, 18d Lead wire

Claims (10)

A frame having a through hole;
A first metal plate joined to the frame in the through hole;
A second metal plate that is joined to the frame in the through-hole and is arranged at a predetermined interval from the first metal plate and having a plurality of notches penetrating in a predetermined region;
A laminate that is interposed between the first metal plate and the second metal plate in the through-hole, and alternately laminated with piezoelectric films and metal films, and has at least two piezoelectric films;
With
The electroacoustic transducer, wherein the piezoelectric film is made of a piezoelectric resin material.   The electroacoustic transducer according to claim 1, wherein each of the first metal plate, the second metal plate, and the metal film is thinner than the piezoelectric film.   The electroacoustic transducer according to claim 1 or 2, wherein the piezoelectric film has a thickness of 50 µm or more and 500 µm or less.   The electroacoustic transducer according to any one of claims 1 to 3, wherein the through hole is formed in a circular shape or a rectangular shape when viewed from above the plate surface of the second metal plate. A plurality of the through holes are formed side by side in a predetermined direction in the frame,
5. The electroacoustic transducer according to claim 1, wherein the first metal plate, the second metal plate, and the laminated body are disposed in each through-hole. The end of the first metal plate is joined to the frame over the entire circumference,
The second metal plate has a convex portion extending outward between the adjacent cutout portions,
The electroacoustic transducer according to claim 1, wherein an end portion of the convex portion is joined to the frame. The end of the first metal plate is joined to the frame over the entire circumference,
The end of the second metal plate is joined to the frame over the entire circumference,
The electroacoustic transducer according to claim 1, wherein the notch is formed so as not to include an end of the second metal plate. The laminate is disposed away from the frame,
The electroacoustic transducer according to any one of claims 1 to 7, wherein the notch is formed in a region other than a region where the stacked body is disposed in the second metal plate.   The electroacoustic conversion according to any one of claims 1 to 8, wherein each of the first metal plate, the second metal plate, and the metal film is electrically connected to a corresponding lead terminal. vessel.   10. An electronic device, wherein the electroacoustic transducer according to claim 1 is mounted.

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