JP4597105B2 - Speaker and power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker capable of suppressing reduction in sound reproducibility and sound pressure, with respect to the speaker in which a medium is enclosed and which generates sound by driving a piezoelectric/electrostriction element fixedly disposed on a driving plate. <P>SOLUTION: A speaker body comprises a driving plate 132, a piezoelectric/electrostriction element 141 fixedly disposed on the driving plate 132, a diaphragm 142 for radiating sonic waves to the outside, and a fixed part 133 for supporting the driving plate 132 and the diaphragm 142. A medium for transporting the vibration of the driving plate 132 to the diaphragm 142 is enclosed in a cavity formed so as to be demarcated by the driving plate 132, the diaphragm 142 and the fixed part 133. The driving plate 132 and the fixed part 133 are comprised of ceramic and the driving plate 132 and the piezoelectric/electrostriction element 141 are formed integrally by calcination. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

The present invention relates to a speaker, and in particular, transmits vibrations generated by an actuator to a diaphragm using a fluid or gel to emit sound waves. A piezoelectric / electrostrictive element or a giant magnetostrictive element is used as the actuator. About what will be done. The present invention also relates to an electric power generation apparatus using a fluid or gel as a pressure fluctuation medium having a structure related to the structure of the speaker.

  As one of this type of speaker, a sound (sound wave, sound pressure) is generated by vibration of a driving plate generated by driving a piezoelectric / electrostrictive element fixedly arranged on a driving plate (vibrating plate). There is. As described above, a speaker using a piezoelectric / electrostrictive element as an actuator does not require a voice coil or a magnet, and thus has a simple structure and is suitable for reduction in size and weight. Therefore, this type of speaker is widely used for mobile phones and the like.

Japanese Patent Application Laid-Open No. 2004-151561 discloses a speaker (casing) in which liquid (medium) is enclosed and a drive plate is in contact with the liquid, among these types of speakers. Thus, it is described that the resonance frequency of the drive plate can be lowered and the sound pressure in the low sound range can be increased.
JP 2002-247695 A

  By the way, in the speaker described in the above document, a piezoelectric / electrostrictive element is bonded to a metal driving plate. Accordingly, when such adhesion is insufficient, the displacement of the piezoelectric / electrostrictive element is not accurately and sufficiently transmitted to the drive plate (and thus the medium), resulting in a decrease in sound reproducibility, a decrease in sound pressure, and the like. There is a problem that can occur.

Accordingly, an object of the present invention is to reduce the reproducibility of sound in a speaker that generates sound by driving a piezoelectric / electrostrictive element in which a medium is enclosed and fixedly arranged on a drive plate. It is in providing the thing which can suppress the fall of a pressure. In addition, another object is to provide a speaker having excellent reproducibility and directivity in the low sound range. Note that the “second speaker according to the present invention” in the column of the disclosure of the invention is the speaker that is the subject of the present invention, whereas the “first speaker according to the present invention” in the column of the disclosure of the invention is the book. Although it is a speaker related to the invention, it is not a speaker which is a subject of the present invention.

  A first speaker according to the present invention includes a drive plate portion, a piezoelectric / electrostrictive element that is fixedly disposed on the drive plate portion and drives the drive plate portion, and a vibration plate portion for emitting sound waves to the outside. And a fixed portion that supports the drive plate portion and the vibration plate portion, and vibrations of the drive plate portion that are enclosed in a cavity defined by at least the drive plate portion, the vibration plate portion, and the fixed portion. For transmitting to the diaphragm part.

  According to the above configuration, the driving plate portion vibrates by driving (displacement) of the piezoelectric / electrostrictive element supplied with the audio signal as the driving signal, and the vibration is transmitted to the vibrating plate portion via the medium. Thereby, the diaphragm part vibrates, and the vibration is radiated to the outside as a sound wave. As a result, a sound corresponding to the pattern of the audio signal is generated.

  The first speaker according to the present invention is characterized in that at least the drive plate portion is made of ceramics, and the drive plate portion and the piezoelectric / electrostrictive element are integrated by firing. According to this, the drive plate part made of ceramics and the piezoelectric / electrostrictive element are reliably integrated by firing. In other words, the drive plate portion and the piezoelectric / electrostrictive element can be joined (integratedly fixed) over the entire boundary surface between the drive plate portion and the piezoelectric / electrostrictive element. As a result, the displacement of the piezoelectric / electrostrictive element can be accurately and sufficiently transmitted to the drive plate (and thus the medium), so that it is possible to suppress a decrease in sound reproducibility and a decrease in sound pressure. In addition, since the wave (pressure wave) generated from the drive plate portion uniformly hits the diaphragm portion via the medium, the reproducibility (particularly in the low frequency range) is high and directivity is high. High sound can be generated.

  In this case, it is preferable that the diaphragm portion has a structure in which at least a part of the edge portion of the diaphragm portion is more easily deformed than the central portion of the diaphragm portion. According to this, the diaphragm part vibrates by positively deforming at least a part of the edge part of the diaphragm part without almost deforming the center part of the diaphragm part. In other words, when the diaphragm part vibrates, a wide range of the central part of the diaphragm part can be greatly displaced in a direction perpendicular to the plane of the diaphragm part. Therefore, it is possible to increase the amount of air that is eliminated by the vibration of the diaphragm, and as a result, it is possible to increase the sound pressure.

  Thus, in order to obtain a structure in which at least a part of the edge of the diaphragm part is more easily deformed than the center part, for example, the thickness of at least a part of the edge part of the diaphragm part is set to the same diaphragm. What is necessary is just to make it thinner than the center part of a part. Alternatively, at least a part of the edge portion of the diaphragm portion may be bent in a bowl shape. Furthermore, at least a part of the edge portion of the diaphragm portion may be made of a material having a Young's modulus smaller than that of the central portion of the diaphragm portion.

  In the first speaker according to the present invention, the fixed portion has a structure in which a support portion that is a portion supporting the drive plate portion in the fixed portion is more easily deformed than other portions. Is preferred. According to this, the resonance frequency of the drive plate part can be lowered, and the sound pressure in the low sound range can be increased.

  Thus, in order to obtain a structure in which the support portion of the fixed portion is more easily deformed than other portions, for example, the cross-sectional area in the direction along the plane of the drive plate portion of the support portion of the fixed portion is the same. What is necessary is just to make it smaller than the said other part in a fixing | fixed part. Or what is necessary is just to comprise the said support part in the said fixing | fixed part from the material whose Young's modulus is smaller than the said other part. With these configurations, the stiffness of the support portion can be reduced, and the resonance frequency of the drive plate portion can be lowered.

  In the first speaker according to the present invention, it is more preferable that the piezoelectric / electrostrictive elements are fixedly arranged on a plurality of the driving plate portions. According to this, by supplying an audio signal having the same pattern to each of the plurality of piezoelectric / electrostrictive elements, vibration (amplitude) transmitted to the diaphragm portion via the medium can be increased. Therefore, the vibration (amplitude) of the diaphragm portion is increased, and the sound pressure can be increased. Also, by providing a plurality of piezoelectric / electrostrictive elements, it is possible to simultaneously generate vibrations having different frequencies.

  In the first speaker according to the present invention, it is preferable that the drive plate portion and the diaphragm portion exist on one plane. According to this, by using the sound wave radiated to the outside by the vibration of the vibration plate part and the sound wave radiated to the outside by the vibration of the drive plate part in the same direction and phase, Interference prevention means (housing, enclosure) for preventing the interference between the sound wave radiated to the outside and the sound wave radiated to the outside due to the vibration of the drive plate portion becomes unnecessary.

  In the first speaker according to the present invention, it is preferable that all of the fixed portion is made of ceramics. According to this, the fixed portion and the drive plate portion made of ceramics can be integrally formed by firing, and the manufacturing cost can be reduced. Furthermore, the diaphragm portion may be made of ceramics. In this case, not only the fixed portion and the drive plate portion but also the diaphragm portion can be integrally formed by firing, and the manufacturing cost can be further reduced.

  A second speaker according to the present invention includes a piezoelectric / electrostrictive element having a shape having an internal space on the inside, a diaphragm for radiating sound waves to the outside, and at least an internal space of the piezoelectric / electrostrictive element. And a medium enclosed in a cavity defined by the diaphragm and transmitting the vibration of the piezoelectric / electrostrictive element to the diaphragm.

  According to the above configuration, the vibration (pressure wave) of the piezoelectric / electrostrictive element supplied with the audio signal as the drive signal is directly transmitted to the medium and is also transmitted to the diaphragm portion via the medium. Thereby, the diaphragm part vibrates, and the vibration is radiated to the outside as a sound wave. As a result, a sound corresponding to the pattern of the audio signal is generated.

  According to this, since the vibration (displacement) of the piezoelectric / electrostrictive element can be accurately and sufficiently transmitted to the medium, the sound reproducibility is reduced and the sound is reduced as in the first speaker according to the present invention described above. A decrease in pressure can be suppressed.

  In this case, it is preferable that the internal space of the piezoelectric / electrostrictive element is partitioned into a plurality of spaces. According to this, the vibration (pressure wave) of the piezoelectric / electrostrictive element can be transmitted to the diaphragm portion more efficiently.

  In any of the loudspeakers according to the present invention, the medium is preferably a fluid, and a liquid is preferable among the fluids. Liquids have characteristics such as less sound attenuation, faster transmission speed, and lower compression ratio than gas. Accordingly, by using a liquid as the medium as in the above configuration, the efficiency of converting the pressure wave generated from the drive plate portion into the sound wave generated by the vibration plate portion can be increased. In addition, since the entire diaphragm is pressed by the pressure wave by the fluid, a highly directional sound is generated as compared with the case where the piezoelectric / electrostrictive element is directly arranged on the diaphragm and the diaphragm is directly vibrated. Can do.

  In any of the speakers according to the present invention, the medium is preferably a gel. Gel is a polymer that has the characteristics of both an elastic solid and a viscous liquid, and since it has the characteristics of both a solid and a liquid, it has a lower resistance (reaction force) than a solid and a compression ratio compared to a gas. Is small. Therefore, as described above, by using gel as the medium, the efficiency of converting the pressure wave generated from the drive plate portion into the sound wave generated by the vibration plate portion can be increased. It is also possible to fill the cavity with a gel precursor and then make it gel. Therefore, productivity can be increased. In addition, the seal structure for preventing leakage of the medium to the outside can be simplified as compared with the case where the medium is water or the like.

  Here, the gel used as the medium is preferably one having fluidity. The type of gel may be appropriately selected by changing the structure of the gel such as the crosslinking density according to the characteristics of the frequency used. For example, polymer gels such as polyethylene, polyurethane, silicon, and PVA can be applied. In addition, since the speaker is generally used at room temperature, a plasticizer for lowering Tg to room temperature or lower may be added to the gel in order to increase the fluidity of the gel at room temperature. Moreover, what contained water | moisture content (liquid) like swelling gel like agar, gelatin, and polyhydroxyethyl methacrylate (PHEMA) may be used. By using the swollen gel, the filling rate in the cavity can be increased.

  In any of the speakers according to the present invention, the piezoelectric / electrostrictive element may be supplied with an ultrasonic signal amplitude-modulated with an audio signal as a drive signal. According to this, the magnitude of the force that the diaphragm receives through the medium due to the vibration (displacement) of the piezoelectric / electrostrictive element generated by the supply of the ultrasonic signal is the modulation component (audio signal component). Will change accordingly. Accordingly, a sound wave corresponding to the modulation component is radiated from the diaphragm portion to the outside. As a result, a sound corresponding to the pattern of the audio signal is also generated.

  In any of the speakers according to the present invention, a giant magnetostrictive element using a giant magnetostrictive material may be used instead of the piezoelectric / electrostrictive element. The giant magnetostrictive element can obtain a larger displacement than the piezoelectric / electrostrictive element. Therefore, according to this, the sound pressure can be further increased.

Further, in the first speaker according to the present invention, an input plate portion that is deformed by receiving an external force by replacing the drive plate portion with an output plate portion and the diaphragm portion with an input plate portion, and An output plate portion, a piezoelectric / electrostrictive element that is fixedly disposed on the output plate portion and generates electric power according to deformation of the output plate portion, and a fixed portion that supports the input plate portion and the output plate portion And at least the input plate portion, the output plate portion, and the fixed portion enclosed in a cavity formed and transmitted to the output plate portion by transmitting pressure based on deformation of the input plate portion. A power generation device including a medium for deforming a portion, wherein at least the output plate portion is made of ceramics, and the output plate portion and the piezoelectric / electrostrictive element are integrated by firing. It may be provided the power generating apparatus characterized

That is, when a force (pressure) is applied to the input plate portion from the outside, the input plate portion is deformed according to the magnitude of this force. When the input plate portion is deformed, a medium pressure is generated in accordance with the deformation of the input plate portion. The output plate portion is deformed according to the pressure of the medium. When the output plate portion is deformed, the piezoelectric / electrostrictive element generates electric power according to the deformation of the output plate portion. As described above, when a force (pressure) is applied to the input plate portion from the outside, the piezoelectric / electrostrictive element generates electric power corresponding to the magnitude of this force. Therefore, this power generation device functions as a sensor that detects the magnitude of force (pressure) applied to the input plate portion in an analog manner, for example .

Moreover, in this electric power generator , since the input board part and the output board part are separated, the output board part is hard to be damaged. In addition, this sensor can be easily manufactured simply by enclosing a medium such as a liquid or gel in the cavity.

In this power generator , the size and number of input plate portions can be freely changed. Preferably, in the power generation device , a plurality of the input plate portions are provided, and the medium is preferably a liquid or a gel.

As an application of the power generation device , in addition to the above-described force (pressure) sensor, a three-dimensional sensor (microphone), a fingerprint sensor, a flow rate sensor, a fluid sensor such as a liquid amount sensor, a viscosity sensor, and the like can be cited. The power generation device can also be used for electronic portable devices such as mobile phones and personal computer input devices such as mice.

  Hereinafter, embodiments of a speaker according to the present invention will be described with reference to the drawings.

(First embodiment)
The speaker 100 according to the first embodiment of the present invention is shown in FIG. 1 representing the plan view thereof and FIG. 2 which is a cross-sectional view of the speaker 100 cut along a plane along line 1-1 of FIG. , An enclosure 110 and a speaker main body 120.

  The enclosure 110 has a bottomed circular cylindrical shape along the XY plane, and has a bottomed cylindrical shape erected in the positive Z-axis direction. A rectangular opening 111 is provided on the upper surface of the enclosure 110 (a plane along the XY plane in the positive direction of the Z axis).

  The speaker body 120 has a substantially rectangular parallelepiped shape that extends parallel to the X, Y, and Z axes whose sides are orthogonal to each other. The speaker main body 120 is exposed so that only an upper surface (a plane along the XY plane in the positive direction of the Z axis) corresponding to a diaphragm 142 (see FIG. 3 or the like) described later is exposed from the opening 111 to the outside. It is embedded in the enclosure 110 so that the air in the enclosure 110 is sealed.

  Thereby, the sound wave radiated from the diaphragm 142 of the speaker main body 120 and the drive plate portion 132 described later corresponding to the lower surface of the speaker main body 120 (a plane along the XY plane in the negative Z-axis direction) are emitted. The interference with the sound wave is prevented, and the sound wave radiated from the diaphragm 142 is transmitted to the outside through the opening 111 as a sound.

  Hereinafter, the speaker body 120 will be described in detail. In the following drawings used in this description, for convenience of description, the speaker body 120 is shown rotated 180 degrees around the X axis from the state shown in FIGS. 1 and 2 (upside down). (The same applies to the second and subsequent embodiments).

  The speaker main body 120 is a cross-sectional view of the speaker main body 120 cut along a plane p1 (a plane along the XZ plane corresponding to the center position in the Y-axis direction of the speaker main body 120) in FIGS. 4, FIG. 5 representing the plan view thereof, and FIG. 6 representing the bottom view thereof, each side has a substantially rectangular parallelepiped shape extending in parallel to the X, Y, and Z axes orthogonal to each other. A base portion 130 made of ceramics, a piezoelectric / electrostrictive element 141 fixedly arranged at a predetermined position on the upper surface of the base portion 130 (a plane along the XY plane in the negative Z-axis direction), and the lower surface of the base portion 130 ( And a metal diaphragm 142 fixedly disposed so as to cover the entire lower surface of the Z-axis positive direction along a plane along the XY plane.

  The base body part 130 is formed with a rectangular parallelepiped recess 131 that opens downward (in the positive Z-axis direction). As a result, the base plate portion 130 is formed with a drive plate portion 132 that forms the bottom plate of the recess 131 and a fixing portion 133 that forms the side surface of the recess 131 and the side surface of the base portion 130. As a result, the drive plate portion 132 and the vibration plate 142 are supported by the fixed portion 133.

  A pair of left and right grooves 134 and 134 that are recessed in a direction along the plane (XY plane) of the drive plate portion 132 are formed in the support portion 133a that is a portion that supports the drive plate portion 132 in the fixed portion 133. Yes. Thereby, the support part 133a in the fixed part 133 has a smaller cross-sectional area in the direction along the plane (XY plane) of the drive plate part 132 than the other part in the fixed part 133.

  The piezoelectric / electrostrictive element 141 has a plurality of layered electrodes and a plurality of piezoelectric / electrostrictive layers (in this example, four piezoelectric / electrostrictive layers), and the layered electrodes and the piezoelectric / electrostrictive layers are alternately arranged. It is a laminated body laminated in the vertical direction (Z-axis direction), and has a substantially rectangular parallelepiped shape in which each side extends parallel to the X, Y, and Z axes perpendicular to each other. The central portion of the piezoelectric / electrostrictive element 141 is fixedly disposed at a portion corresponding to the recess 131 on the upper surface of the drive plate portion 132 (a plane along the XY plane in the negative Z-axis direction). The portions (both ends in the X-axis direction) extend to portions corresponding to the support portions 133a on the upper surface of the drive plate portion 132.

  The diaphragm 142 constitutes the diaphragm section. Lower surfaces (planes along the XY plane in the positive direction of the Z axis) of both left and right end portions (both end portions in the X axis direction, at least a part of the edge portion of the diaphragm portion) in the portion corresponding to the recess 131 in the diaphragm 142 Is provided with a pair of grooves 142a, 142a having an arcuate cross section extending in the Y-axis direction. As a result, the portion of the diaphragm 142 corresponding to the grooves 142 a and 142 a (at least a part of the edge of the diaphragm portion) is thinner than the central portion of the diaphragm 142.

  The concave portion 131 of the base portion 130 is closed by the diaphragm 142. As a result, a cavity 135 is defined by the lower surface of the drive plate portion 132, the upper surface of the vibration plate 142 (vibration plate portion), and the side surface of the fixed portion 133. The fixed portion 133 is formed with passages 136 and 137 for injecting a medium that communicates the inside of the cavity 135 with the outside. The passages 136 and 137 are sealed with sealing plugs 143 and 144, respectively. As a result, the cavity 135 forms a sealed space, and a medium (gel in this example) made of a predetermined component is enclosed in the cavity 135.

  Next, a method for manufacturing the speaker body 120 will be described. The base portion 130 (that is, the drive plate portion 132 and the fixing portion 133) made of ceramics in the speaker main body 120 is preferably manufactured using a ceramic green sheet laminating method. According to the ceramic green sheet laminating method, it is possible to integrally form the base portion 130 having a complicated shape, and there is almost no change in the state of the joint portion between the sheets over time. This is because the reliability can be increased and the rigidity can be ensured. Therefore, in this example, the base portion 130 is manufactured using a ceramic green sheet lamination method.

  First, a slurry is prepared by adding a binder, a solvent, a dispersant, a plasticizer, etc. to a ceramic powder such as zirconia, alumina, silicon nitride, aluminum nitride, titania, magnesia, mullite, etc. A rectangular ceramic green sheet having a predetermined thickness is produced by a method such as a roll coater method or a doctor blade method. Here, the zirconia, in particular, the material mainly composed of stabilized zirconia and the material mainly composed of partially stabilized zirconia, are high in mechanical strength and toughness, and thus the base portion 130 (that is, the drive plate portion 132 and the fixed portion). 133) is preferable as a material.

  Next, as shown in FIG. 7, the ceramic green sheets are processed into various shapes by a method such as punching using a mold or laser processing as necessary, and a plurality of ceramic green sheets 151 to 156 are processed. Get. In addition, the length of each side of the plane of the ceramic green sheets 151 to 156 (length of vertical and horizontal sides of the rectangular plane) may be defined by cutting after stacking. Thereby, at the time of lamination | stacking, the ceramic green sheet which has the same rectangular external shape can be used, and a processing precision can be improved.

  In the example shown in FIG. 7, rectangular windows Wd <b> 1 to Wd <b> 5 that later constitute the cavity 135 are formed on the ceramic green sheets 152 to 156, respectively. The windows Wd1 to Wd5 have the same shape. The ceramic green sheet 152 is formed with notches K1 and K2 that will form the grooves 134 and 134 later. The ceramic green sheets 154 and 155 are respectively formed with grooves G1 and G2 that will later constitute the passages 136 and 137, respectively. The number of ceramic green sheets is only an example. In the illustrated example, the ceramic green sheets 153 and 156 may be a single green sheet having a predetermined thickness, or a plurality of ceramic green sheets are laminated or laminated to obtain the predetermined thickness. It may be what you did.

  Thereafter, as shown in FIG. 8, ceramic green sheets 151 to 156 are laminated and pressure-bonded to form a ceramic green sheet laminate 160. Next, the ceramic green sheet laminate is fired to form the ceramic laminate 170 shown in FIG.

  Next, as shown in FIG. 10, piezoelectric / electrical current is applied to the upper surface of the ceramic laminate 170 (a plane along the XY plane in the negative Z-axis direction), that is, the fired surface of the laminated ceramic green sheet 151. A strained layer stack 180 is formed. Here, electrodes are disposed on the upper and lower surfaces of each piezoelectric / electrostrictive layer as necessary. As the piezoelectric / electrostrictive layer, for example, lead zirconate titanate (PZT), barium titanate, or potassium sodium niobate can be used. As the electrode, gold, silver, platinum or the like is used as necessary. The piezoelectric / electrostrictive layer stack 180 and the electrodes can be formed by a thick film forming method such as a screen printing method, a dipping method, a coating method, and an electrophoresis method, an ion beam method, a sputtering method, a vacuum deposition method, an ion plate method, or the like. Thin film formation methods such as a plating method, chemical vapor deposition (CVD), and plating can be used.

  Next, the ceramic laminate 170 on which the piezoelectric / electrostrictive layer laminate 180 is formed is integrally fired to form the base portion 130 on which the piezoelectric / electrostrictive element 141 is formed. Thereby, the drive plate part 132 of the base | substrate part 130 and the piezoelectric / electrostrictive element 141 are integrated. Thus, by forming the piezoelectric / electrostrictive layer laminate 180 using a film formation method (particularly, a thick film formation method), the piezoelectric / electrostrictive layer laminate 180 and the ceramic laminate can be formed without using an adhesive. The body 170 (therefore, the piezoelectric / electrostrictive element 141 and the base portion 130) can be integrally joined (arranged).

  In addition, the piezoelectric / electrostrictive layer laminate 180 is formed on the upper surface of the ceramic green sheet laminate 160 (a plane along the XY plane in the negative Z-axis direction), that is, on the surface of the laminated ceramic green sheet 151 before firing. The ceramic green sheet laminate 160 and the piezoelectric / electrostrictive layer laminate 180 may be fired at the same time.

  Further, in manufacturing the “base portion 130 on which the piezoelectric / electrostrictive element 141 is formed”, a single sheet equivalent to a plurality of the ceramic laminates of FIG. 9 arranged vertically and horizontally is prepared. By forming a plurality of piezoelectric / electrostrictive layer stacks 180 (see FIG. 10), which will later become piezoelectric / electrostrictive elements 141, on a surface, a predetermined portion is continuously formed, and this sheet is cut. It is desirable to manufacture a large number of “base portions 130 on which the piezoelectric / electrostrictive elements 141 are formed” in the same process.

  Next, as shown in FIG. 11, it is prepared in advance on the lower surface of the base portion 130 (a plane along the XY plane in the Z-axis positive direction), that is, on the surface after firing of the laminated ceramic green sheets 156. A certain metal diaphragm 142 is bonded and fixed with an adhesive.

  Then, the gel is injected into the cavity 135 in the base portion 130 using the passages 136 and 137 of the base portion 130 to which the vibration plate 142 is bonded. Finally, the sealing plugs 143 and 144 are provided in the passages 136 and 137. The gel is sealed in the cavity 135 by fitting each. In this way, the speaker body 120 is manufactured.

  Next, the operation of the speaker 100 in which the speaker main body 120 is embedded according to the first embodiment of the present invention constructed and configured in this manner will be described. When an audio signal as a drive signal is supplied from a drive circuit (not shown) electrically connected to the piezoelectric / electrostrictive element 141 to the piezoelectric / electrostrictive element 141, the piezoelectric / electrostrictive element 141 responds to the audio signal. Thus, it expands and contracts along the X-axis direction.

  As a result, the drive plate portion 132 integrated with the piezoelectric / electrostrictive element 141 vibrates, and the vibration is transmitted to the vibration plate 142 via the gel enclosed in the cavity 135. Thereby, the diaphragm 142 vibrates. The vibration of the diaphragm 142 is radiated to the outside as a sound wave through the opening 111 of the enclosure 110. As a result, a sound corresponding to the pattern of the audio signal is generated from the speaker 100.

  By the way, in the first embodiment, as described above, the driving plate portion 132 made of ceramics and the piezoelectric / electrostrictive element 141 are reliably integrated by firing, and the driving plate portion 132 and the piezoelectric / electrostrictive element are integrated. The drive plate portion 132 and the piezoelectric / electrostrictive element 141 can be joined over the entire boundary surface with the 141. As a result, the expansion / contraction displacement of the piezoelectric / electrostrictive element 141 can be accurately and sufficiently transmitted to the drive plate portion 132 (and thus the gel in the cavity 135). Accordingly, it is possible to suppress a decrease in sound reproducibility and a decrease in sound pressure.

  In the first embodiment, as described above, the support portion 133a, which is the portion that supports the drive plate portion 132 in the fixed portion 133, is formed in the other portion of the fixed portion 133 by forming the pair of left and right grooves 134, 134. The sectional area in the direction along the plane (XY plane) of the drive plate portion 132 is smaller than that. Thereby, the fixing | fixed part 133 becomes a structure where the support part 133a is easy to deform | transform rather than another part. As a result, the resonance frequency of the drive plate portion 132 can be reduced, and the sound pressure in the low sound range can be increased.

  Further, in the first embodiment, as described above, the portion corresponding to the grooves 142a and 142a of the diaphragm 142 (at least part of the edge of the diaphragm portion) vibrates by forming the pair of left and right grooves 142a and 142a. The thickness is thinner than the central portion of the plate 142. Accordingly, the diaphragm 142 has a structure in which at least a part of the edge portion of the diaphragm portion is more easily deformed than the center portion of the diaphragm 142. Accordingly, the diaphragm 142 vibrates by positively deforming at least a part of the edge of the diaphragm part without almost deforming the central part of the diaphragm 142. In other words, when the diaphragm 142 vibrates, a wide range at the center of the diaphragm 142 can be greatly displaced in the direction perpendicular to the plane of the diaphragm 142. Accordingly, it is possible to increase the amount of air that is excluded by the vibration of the diaphragm 142, and as a result, it is possible to increase the sound pressure. In addition, a wide range in the central portion of the diaphragm 142 is greatly displaced in a direction perpendicular to the plane of the diaphragm 142, so that a highly directional sound can be emitted.

  In the first embodiment, the speaker body 120 is embedded in the enclosure 110 so that the plane of the diaphragm 142 is at a position lower than the upper surface of the enclosure 110 by a predetermined height (position in the negative Z-axis direction in FIG. 2). Has been. Thereby, the directivity can be increased and the sound pressure can be increased.

  In the first embodiment, a gel is used as a medium enclosed in the cavity. Thereby, the seal structure for preventing the leakage of the medium to the outside at the joint surface between the base portion 130 and the diaphragm 142 can be simplified.

  As described above, according to the speaker 100 according to the first embodiment of the present invention, it is possible to provide a speaker that can suppress a decrease in sound reproducibility and a decrease in sound pressure.

  The present invention is not limited to the first embodiment, and various modifications can be employed within the scope of the present invention. For example, in the first embodiment, in order to obtain a structure in which at least a part of the edge of the diaphragm part is more easily deformed than the center part of the diaphragm 142, a pair of left and right grooves 142a and 142a are used as the diaphragm part. As shown in FIG. 12, only the material corresponding to the pair of left and right grooves 142a and 142a is made of a material having a Young's modulus smaller than that of metal (as shown in FIG. 12). For example, a metal diaphragm 142 ′ changed to rubber or the like may be used. Note that a material having a low Young's modulus may be selected as appropriate by paying attention to characteristics (for example, a resonance frequency) depending on the frequency used. Moreover, you may use the same kind of material as the gel with which a cavity is filled.

  In the first embodiment, the area of the portion of the drive plate 132 that contacts the cavity 135 is equal to the area of the portion of the diaphragm 142 that contacts the cavity 135. However, as shown in FIG. By using the base portion 130 ′ having the cavity 135 ′ whose sectional area in the direction along the plane of the vibration plate 142 decreases as the distance from the surface of the vibration plate 142 approaches, the area of the portion in contact with the cavity 135 ′ in the vibration plate 142 can be reduced. The area of the portion in contact with the cavity 135 ′ in 132 ′ may be smaller. Such a base | substrate part 130 'can be formed by changing the number of sheets, shape, etc. of a ceramic green sheet. Thereby, the amplitude (in the Z-axis direction) of the diaphragm 142 can be increased, and an increase in sound pressure can be expected.

  In the first embodiment, the diaphragm 142 made of metal is used as the diaphragm, but the diaphragm is more easily deformed than the ceramics constituting the base 130 (the Young's modulus is small). ) You may use the diaphragm which consists of other materials (for example, resin film etc.). Further, the base portion and the diaphragm portion may be integrally formed using a ceramic green sheet lamination method.

(Second Embodiment)
Next, the speaker 200 according to the second embodiment of the present invention will be described. In order to obtain a structure in which the support portion that supports the drive plate portion in the fixed portion is more easily deformed than the other portions in the fixed portion, this speaker 200 is made of only the material of the portion corresponding to the support portion in the fixed portion made of ceramics. The only difference from the speaker 100 according to the first embodiment is that the material is changed to a material having a Young's modulus smaller than that of ceramic (in this example, rubber).

  That is, the speaker 200 has the same shape as the enclosure 110 shown in FIGS. 1 and 2 and the speaker main body 120 of the first embodiment, and is similar to the speaker main body 120 and is embedded in the enclosure 110 for the second embodiment. The speaker main body 220 is comprised.

  Hereinafter, the speaker main body 220 is cut along a plane p2 (a plane along the XZ plane corresponding to the center position in the Y-axis direction of the speaker main body 220) of FIG. 14 and FIG. Description will be made with reference to FIG. 15 which is a sectional view, FIG. 16 which shows a plan view thereof, and FIG. 17 which shows a bottom view thereof. As the reference numerals attached to the respective members, parts, etc. in the speaker main body 220 for the second embodiment, only the hundreds are different from the reference numerals of the corresponding members, parts, etc. in the speaker main body 120 for the first embodiment. By using each, it replaces with description of each member, a site | part, etc. in the speaker main body 220 (same also in embodiment after 3rd Embodiment mentioned later).

  As shown in FIGS. 14-17, in the speaker main body 220, the support part 233a which consists of rubber | gum is provided in the part corresponding to the support part 133a and the groove | channel 134 of 1st Embodiment in the fixing | fixed part 233 which consists of ceramics. . In other words, the drive plate portion 232 is supported by the support portion 233a made of rubber.

  Hereinafter, a method for manufacturing the speaker body 220 will be described. First, similarly to the first embodiment, a rectangular ceramic green sheet having a predetermined thickness is produced by a method such as a doctor blade method.

  Next, as shown in FIG. 18, the ceramic green sheets are processed into various shapes by a method such as punching using a mold or laser processing as necessary, and a plurality of ceramic green sheets 251 to 256 are processed. Get.

  In the example shown in FIG. 18, rectangular windows Wd11 to Wd14 that later form cavities 235 are formed on the ceramic green sheets 253 to 256, respectively. The windows Wd11 to Wd14 have the same shape. The ceramic green sheet 251 is formed with a window Wd15 for pouring rubber constituting the support portion 233a as will be described later. In the ceramic green sheet 252, a cavity 235 is formed later, and a window Wd16 for securing a space for holding the poured rubber is formed in a portion corresponding to the support portion 233a. In other words, the window Wd16 has a shape that is wider in the left-right direction than the windows Wd11 to Wd14 by an amount corresponding to the space for holding the poured rubber.

  The ceramic green sheets 254 and 255 are respectively formed with grooves G11 and G12 that constitute the passages 236 and 237, respectively. The number of ceramic green sheets is only an example. In the illustrated example, the ceramic green sheets 253 and 256 may be a single green sheet having a predetermined thickness, or a plurality of ceramic green sheets are stacked or stacked to obtain the predetermined thickness. It may be what you did.

  Thereafter, as shown in FIG. 19, ceramic green sheets 251 to 256 are laminated and pressure-bonded to form a ceramic green sheet laminate 260. Next, the ceramic green sheet laminate is fired to form the ceramic laminate 270 shown in FIG.

  Next, as shown in FIG. 21, piezoelectric / electrical current is applied to the upper surface of the ceramic laminate 270 (a plane along the XY plane in the negative Z-axis direction), that is, the fired surface of the laminated ceramic green sheet 251. A strained layer stack 280 is formed. As a method for forming the piezoelectric / electrostrictive layer stack 280, a screen printing method or the like can be used as in the first embodiment.

  Next, the ceramic laminate 270 on which the piezoelectric / electrostrictive layer laminate 280 is formed is integrally fired to form the piezoelectric / electrostrictive element 241. Thereby, similarly to the first embodiment, the piezoelectric / electrostrictive layer stack 280 and the ceramic stack 270 can be integrally bonded (arranged) without using an adhesive.

  Subsequently, high-temperature liquid rubber (rubber precursor) is poured from a pair of windows corresponding to the window Wd15 on the upper surface of the “ceramic laminate 270 on which the piezoelectric / electrostrictive element 241 is formed”. At that time, in order to prevent the liquid rubber from flowing into the space constituting the cavity 235 later, a jig having a convex portion having the same shape as the cavity 235 is prepared, and the cavity 235 is later constituted by the convex portion of the jig. It is preferable to pour the liquid rubber in a state of being fitted in the space. As a result, the liquid rubber is surely held and filled in the portion that will later constitute the support portion 233a.

  Next, after the liquid rubber is solidified by standing at room temperature for a predetermined time, the ceramic laminate 270 is cut along the cutting lines C1 and C2 shown in FIG. As a result, as shown in FIG. 22, the “base portion 230 on which the piezoelectric / electrostrictive element 241 is formed” is formed.

  Next, as shown in FIG. 23, it is prepared in advance on the lower surface of the base portion 230 (a plane along the XY plane in the positive Z-axis direction), that is, on the surface after firing of the laminated ceramic green sheets 256. A certain metallic diaphragm 242 is bonded and fixed with an adhesive.

  Then, gel is injected into the cavity 235 in the base member 230 using the passages 236 and 237 of the base member 230 to which the vibration plate 242 is bonded, and finally the sealing plugs 243 and 244 are provided in the passages 236 and 237. The gel is enclosed in the cavity 235 by fitting each. In this way, the speaker body 220 is manufactured.

  Thus, in 2nd Embodiment, in the fixing | fixed part 233 which consists of ceramics, only the support part 233a which supports the drive plate part 232 is comprised from the rubber | gum. Thereby, like 1st Embodiment, the fixing | fixed part 233 becomes a structure where the support part 233a tends to deform | transform rather than another part. As a result, the resonance frequency of the drive plate portion 232 can be reduced, and the sound pressure in the low sound range can be increased.

  The present invention is not limited to the second embodiment, and various modifications can be employed within the scope of the present invention. For example, in the second embodiment, as in the first embodiment, in order to obtain a structure in which at least a part of the edge of the diaphragm portion is more easily deformed than the center portion of the diaphragm 242, as the diaphragm portion, Although the diaphragm 242 having the pair of left and right grooves 242a and 242a is used, as shown in FIG. 12 described above, only the material of the portion corresponding to the pair of left and right grooves 242a and 242a is used as the diaphragm. You may use the diaphragm made from a metal changed into the material (for example, rubber | gum etc.) whose Young's modulus is smaller than a metal.

  In the second embodiment, the diaphragm 242 made of metal is used as the diaphragm. However, as in the first embodiment, the diaphragm is deformed more than the ceramic constituting the base body 230. A diaphragm made of another material (for example, a resin film or the like) that is easy to do (small Young's modulus) may be used. Further, the base portion and the diaphragm portion may be integrally formed using a ceramic green sheet lamination method.

(Third embodiment)
Next, a speaker 300 according to a third embodiment of the present invention will be described. The speaker 300 is provided with a plurality (three) of drive plate portions, and the piezoelectric / electrostrictive elements are fixedly arranged on the drive plate portions, respectively, with the speaker 100 according to the first embodiment. Mainly different.

  That is, the speaker 300 includes the enclosure 110 shown in FIGS. 1 and 2 and the speaker main body 320 for the third embodiment embedded in the enclosure 110.

  Hereinafter, the speaker main body 320 is cut along a plane p3 (a plane along the XZ plane corresponding to the center position in the Y-axis direction of the speaker main body 320) of FIGS. Description will be made with reference to FIG. 25 which is a sectional view, FIG. 26 which is a plan view thereof, and FIG. 27 which is a bottom view thereof. The medium injection passage and the sealing plug are not shown (the same applies to the fourth and subsequent embodiments described later).

  The base portion 330 of the speaker main body 320 shown in FIGS. 24 to 27 is formed by a ceramic green sheet laminating method as in the first and second embodiments. The cavity in which the gel in the base portion 330 is sealed is divided into four parts: a cavity 335a, a cavity 335b, a cavity 335c, and a cavity 335d. These four cavities communicate with each other through communication holes 338a, 338b, and 338c.

  Drive plate portions 332a, 332b, and 332c are provided at positions corresponding to the upper portions (Z-axis negative direction) of the cavities 335a, 335b, and 335c. Piezoelectric / electrostrictive elements 341a, 341b, and 341c are formed and integrated by firing on the upper surfaces (planes along the XY plane in the negative Z-axis direction) of the drive plate portions 332a, 332b, and 332c, respectively.

  A metal diaphragm 342 constituting the diaphragm section is bonded and fixed to the lower surface of the base section 330 (a plane along the XY plane in the positive Z-axis direction). The lower surfaces of both left and right end portions (both end portions in the X-axis direction; at least part of the edge portion of the vibration plate portion) in the portion corresponding to the cavity 335d in the vibration plate 342 (a plane along the XY plane in the positive Z-axis direction) Are provided with a pair of hook-shaped bent portions 342a and 342a extending in the Y-axis direction.

  As described above, in the third embodiment, the piezoelectric / electrostrictive elements are fixedly arranged on a plurality (three) of the drive plate portions. As a result, by supplying an audio signal having the same pattern to each of the plurality of piezoelectric / electrostrictive elements, compared to a case where one piezoelectric / electrostrictive element is fixedly arranged on one drive plate portion. In addition, the total sum of deformation amounts of the drive plate portion due to the expansion / contraction displacement of the piezoelectric / electrostrictive element can be increased. Therefore, vibration (amplitude) transmitted to the diaphragm 342 via the medium (gel) can be increased. Therefore, the vibration (amplitude) of the diaphragm 342 is increased, and the sound pressure can be increased.

  In the third embodiment, due to the formation of the pair of left and right bowl-shaped bent portions 342a and 342a, at least a part of the edge of the diaphragm portion of the diaphragm 342 is more easily deformed than the center portion of the diaphragm 342. It has a structure. As a result, the diaphragm 342 vibrates by positively deforming at least a part of the edge of the diaphragm without substantially deforming the center of the diaphragm 342. Accordingly, it is possible to increase the amount of air that is excluded by the vibration of the diaphragm 342, and as a result, it is possible to increase the sound pressure.

(Fourth embodiment)
Next, a speaker 400 according to a fourth embodiment of the present invention will be described. The speaker 400 is mainly different from the speaker 300 according to the third embodiment in that the drive plate portion and the diaphragm portion are on the same plane.

  In addition, by using the sound wave radiated to the outside by the vibration of the vibration plate part and the sound wave radiated to the outside by the vibration of the driving plate part in the same direction and phase, An enclosure for preventing the interference between the sound wave radiated to the outside and the sound wave radiated to the outside due to the vibration of the drive plate portion becomes unnecessary. That is, the speaker 400 includes only the speaker body 420 for the fourth embodiment.

  Hereinafter, the speaker main body 420 was cut along a plane p4 (a plane along the XZ plane corresponding to the center position in the Y-axis direction of the speaker main body 420) in FIG. 28 and FIG. Description will be made with reference to FIG. 29 which is a sectional view, FIG. 30 which shows a plan view thereof, and FIG. 31 which shows a bottom view thereof.

  The base portion 430 of the speaker main body 420 shown in FIGS. 28 to 31 is formed by a ceramic green sheet laminating method as in the first to third embodiments. The cavity in which the gel in the base body 430 is enclosed is divided into three of a cavity 335a, a cavity 335b, and a cavity 335c. These three cavities communicate with each other through a communication hole 438.

  A vibration plate portion 442a, a drive plate portion 432, and a vibration plate portion 442b are provided at positions corresponding to the upper portions (Z-axis negative direction) of the cavity 335a, the cavity 335b, and the cavity 335c. That is, in this example, not only the fixing portion 433 and the drive plate portion 432 but also the vibration plate portions 442a and 442b are integrally formed by the ceramic green sheet laminating method. The drive plate portion 432 and the vibration plate portions 442a and 442b exist on the same plane (the upper surface of the base body portion 430). A piezoelectric / electrostrictive element 441 is formed and integrated by firing on the upper surface of the drive plate portion 432 (a plane along the XY plane in the negative Z-axis direction).

  As described above, the speaker body 420 of the fourth embodiment is different from the speaker body 320 of the third embodiment (see FIG. 25) in the cavity 335d, the metal diaphragm 342, and the piezoelectric / electrostrictive element. This corresponds to a configuration in which the drive plates 332a and 332c are functioned as the vibration plate portions while removing 341a and 341c.

  As described above, in the fourth embodiment, the drive plate portion 432 and the vibration plate portions 442a and 442b exist on the same plane (the upper surface of the base body portion 430), so that no enclosure is required. Therefore, the entire speaker 400 can be made compact. In particular, the length in the direction (Z-axis direction) in which sound (sound wave) is emitted from the speaker 400 can be shortened.

(Fifth embodiment)
Finally, a speaker 500 according to a fifth embodiment of the present invention will be described. The speaker 500 is mainly different from the speaker 100 according to the first embodiment in that the drive plate portion is omitted and the internal space of the piezoelectric / electrostrictive element having the internal space inside is used as a part of the cavity.

  That is, the speaker 500 includes the enclosure 110 shown in FIGS. 1 and 2 and the speaker main body 520 for the fifth embodiment embedded in the enclosure 110.

  Hereinafter, the speaker body 520 was cut along a plane p5 (a plane along the XZ plane corresponding to the center position in the Y-axis direction of the speaker body 520) in FIGS. Description will be made with reference to FIG. 33 which is a cross-sectional view, FIG. 34 which is a plan view thereof, and FIG. 35 which is a bottom view thereof.

  As shown in FIGS. 32 to 35, the speaker body 520 includes a piezoelectric / electrostrictive element 541, a fixing portion 533, and a diaphragm 542 that is the same as the diaphragm 142 of the first embodiment. The piezoelectric / electrostrictive element 541 has a substantially rectangular parallelepiped shape having a rectangular parallelepiped internal space 541a that opens downward (Z-axis positive direction). The piezoelectric / electrostrictive element 541 includes a plurality of (for example, four) piezoelectric / electrostrictive layers and a plurality of piezoelectric / electrostrictive elements that are respectively provided on the upper and lower surfaces of each piezoelectric / electrostrictive layer. It is composed of a number of piezoelectric / electrostrictive layers formed by sequentially laminating strain elements (in the Z-axis direction).

  The fixing portion 533 is made of resin (plastic) and has a rectangular parallelepiped shape in which a window corresponding to the internal space 541a is formed at the center thereof. The fixing portion 533 is bonded and fixed to the lower surface of the piezoelectric / electrostrictive element 541 (a plane along the XY plane in the negative Z-axis direction).

  The diaphragm 542 is bonded and fixed to the lower surface of the fixing portion (a plane along the XY plane in the negative Z-axis direction). Thus, a cavity 535 that is a sealed space is formed from the internal space 541 a of the piezoelectric / electrostrictive element 541 and the space corresponding to the window of the fixing portion 533. A predetermined medium (gel) is enclosed in the cavity 535.

  Next, the operation of the speaker 500 in which the speaker body 520 according to the fifth embodiment configured as described above is embedded will be described. When an audio signal as a drive signal is supplied to the piezoelectric / electrostrictive element 541 from a drive circuit (not shown) electrically connected to the piezoelectric / electrostrictive element 541, the piezoelectric / electrostrictive element 541 responds to the audio signal. Thus, it expands and contracts along the X axis direction.

  As a result, the piezoelectric / electrostrictive element 541 itself vibrates, and the vibration is directly transmitted to the gel enclosed in the cavity 535 and also transmitted to the diaphragm 542 via the gel. Thereby, the diaphragm 542 vibrates. The vibration of the diaphragm 542 is radiated to the outside as a sound wave through the opening 111 of the enclosure 110. As a result, a sound corresponding to the pattern of the audio signal is generated from the speaker 500.

  As a result, the expansion / contraction displacement of the piezoelectric / electrostrictive element 541 can be accurately and sufficiently transmitted to the gel in the cavity 535. Accordingly, it is possible to suppress a decrease in sound reproducibility and a decrease in sound pressure.

  As described above, according to the loudspeaker according to each embodiment of the present invention, the expansion / contraction displacement of the piezoelectric / electrostrictive element can be accurately and sufficiently transmitted to the medium (and hence the diaphragm portion) in the cavity. Accordingly, it is possible to suppress a decrease in sound reproducibility and a decrease in sound pressure.

  The present invention is not limited to the above embodiments, and various modifications can be employed within the scope of the present invention. For example, in each of the above embodiments, a gel is used as a medium enclosed in the cavity, but a liquid such as a viscous liquid or water may be used. Further, a gas such as helium gas may be used.

  In each of the above embodiments, the medium is directly enclosed in the cavity. However, a medium wrapped with a thin film such as a polymer film may be enclosed in the cavity. In this case, first, a liquid which is a thin film precursor is injected into the cavity, and a bag-like thin film is formed so as to be in contact with all the inner wall surfaces of the cavity. Thereafter, the medium is injected into the internal space of the bag-like thin film in the cavity. Thereby, the medium wrapped with the thin film can be enclosed in the cavity. Moreover, you may solidify only the outer peripheral part (surface part) of a gel so that a fluidity may be given inside a gel, without preparing thin films, such as a polymer film.

  In the fifth embodiment, a piezoelectric / electrostrictive element having one internal space is used, but one having an internal space partitioned into a plurality of spaces may be used. In this case, specifically, for example, the internal space may be divided into a number of elongated rectangular parallelepiped spaces whose longitudinal direction is the Z-axis direction. The piezoelectric / electrostrictive element having such a shape is formed by, for example, forming a piezoelectric / electrostrictive layer of a piezoelectric / electrostrictive element by extruding a precursor (slurry) from a lattice-like slit (for details, for example, a special (See Kaihei 2-251406). Thereafter, sealing is performed as necessary, and a piezoelectric / electrostrictive layer is formed by firing. And thick film forming methods such as screen printing, dipping, coating, and electrophoresis, ion beam, sputtering, vacuum deposition, ion plating, chemical vapor deposition (CVD), and plating The electrode of the piezoelectric / electrostrictive element is formed on a predetermined surface of the formed piezoelectric / electrostrictive layer by a thin film forming method such as the above. Thereby, a piezoelectric / electrostrictive element having such a shape can be manufactured. According to this, the vibration (pressure wave) of the piezoelectric / electrostrictive element can be transmitted to the diaphragm portion more efficiently.

  In the first to fifth embodiments and the various modifications described above, a giant magnetostrictive element using a giant magnetostrictive material may be used instead of the piezoelectric / electrostrictive element. Since the giant magnetostrictive element can obtain a larger displacement than the piezoelectric / electrostrictive element, the sound pressure can be further increased. The super magnetostrictive material refers to a magnetostrictive material having a magnetostriction of several thousand ppm, such as a Tb-Dy-Fe alloy.

  Here, when a giant magnetostrictive element using a giant magnetostrictive material is used in place of the piezoelectric / electrostrictive element in the first to fourth embodiments and the modifications thereof, the giant magnetostrictive element is the driving plate portion. Fixedly placed on top. In this case, the giant magnetostrictive element may be integrated on the driving plate portion by firing, or may be fixed by an inorganic adhesive, thermocompression bonding, anodic bonding, diffusion bonding, or the like. Further, as the drive plate portion, a semiconductor substrate such as a glass substrate or a silicon substrate may be used in addition to ceramics.

  In the first to fifth embodiments and the various modifications described above, when a giant magnetostrictive element using a giant magnetostrictive material is used instead of the piezoelectric / electrostrictive element, a magnetic field for driving the giant magnetostrictive element is used. The magnets and coils necessary for forming the magnets and coils may be arranged directly and integrally around the giant magnetostrictive element (side surface), or around the giant magnetostrictive element by arranging them on the inner wall surface of the enclosure. And may be arranged to face each other with a predetermined gap.

  In each of the above embodiments, an audio signal is supplied to the piezoelectric / electrostrictive element as a drive signal from a drive circuit (not shown) electrically connected to the piezoelectric / electrostrictive element. The ultrasonic signal that has been amplitude-modulated in (5) may be supplied to the piezoelectric / electrostrictive element. According to this, the magnitude of the force that the diaphragm receives through the medium due to the vibration (displacement) of the piezoelectric / electrostrictive element caused by the supply of the ultrasonic signal depends on the modulation component (audio signal component). Change. Accordingly, a sound wave corresponding to the modulation component is radiated from the diaphragm portion to the outside. Accordingly, this also generates a sound corresponding to the pattern of the audio signal.

  In addition, even when a giant magnetostrictive element using a giant magnetostrictive material is used in place of the piezoelectric / electrostrictive element in the first to fifth embodiments and the various modifications described above, as a drive signal An ultrasonic signal amplitude-modulated with an audio signal may be supplied to the giant magnetostrictive element. Also in this case, as in the case of the piezoelectric / electrostrictive element, a sound corresponding to the audio signal pattern is generated.

  The speaker according to each of the above embodiments can also be used as a small ultrasonic transmitter. This small ultrasonic transmitter can also be used as a highly directional earphone.

  Furthermore, if a plurality of small ultrasonic transmitters are used, an earphone that emits a digital pulse wave can be produced. Here, the digital pulse wave means a pulse wave (longitudinal wave) obtained by modulating an analog signal or a digital signal so that a pulse interval has a wavelength. In this case, the volume can be controlled by the operating rate or amplitude of each transmitter.

  By the way, for example, in the speaker main body 120 shown in FIGS. 3 to 6, the sensor can be provided by using the drive plate portion 132 as an output plate portion and the diaphragm 142 as an input plate.

  More specifically, when an external force (pressure) is applied to the input plate, the input plate is deformed according to the magnitude of the force. When the input plate is deformed, the pressure of the medium (gel) in the cavity 135 is generated according to the deformation of the input plate. The output plate portion is deformed according to the pressure of the medium. When the output plate portion is deformed, the piezoelectric / electrostrictive element 141 generates electric power according to the deformation of the output plate portion.

  As described above, when a force (pressure) is applied to the input plate (for example, a plate functioning as a button) from the outside, the piezoelectric / electrostrictive element 141 generates electric power (voltage) corresponding to the magnitude of the force. Therefore, by detecting the electric power (voltage) generated by the piezoelectric / electrostrictive element 141, this sensor detects, for example, the magnitude of the force (pressure) applied to the input plate (eg, button) in an analog manner. Can be a force (pressure) sensor.

  As a usage form of this sensor, for example, a form in which a dial button of a cellular phone functions as the input board can be considered. In this case, since the magnitude of the force applied to the dial button can be detected in an analog manner, for example, the dial button can be used as an accelerator operation member in a car game using a mobile phone terminal.

  As another usage form of the sensor, for example, a form in which a mouse button for a personal computer functions as the input board is conceivable. In this case, since the magnitude of the force applied to the mouse button can be detected in an analog manner, for example, the moving speed of the pointer displayed on the display can be changed according to the magnitude of the force of pushing the mouse button. it can.

1 is a plan view of a speaker according to a first embodiment of the present invention. It is sectional drawing which cut | disconnected the speaker by the plane along the 1-1 line | wire of FIG. It is the perspective view which showed the speaker main body which concerns on 1st Embodiment of this invention. FIG. 4 is a cross-sectional view of the speaker body cut along a plane p1 in FIG. 3. It is a top view of the speaker main body shown in FIG. FIG. 4 is a bottom view of the speaker body shown in FIG. 3. It is a perspective view of the ceramic green sheet laminated | stacked in the manufacturing process of the speaker main body shown in FIG. It is a perspective view of the ceramic green sheet laminated body which laminated | stacked and crimped | bonded the ceramic green sheet shown in FIG. It is a perspective view of the ceramic laminated body formed by baking the ceramic green sheet laminated body shown in FIG. FIG. 10 is a perspective view of the ceramic laminate shown in FIG. 9 on which a piezoelectric / electrostrictive layer laminate is formed. It is a perspective view of the ceramic laminated body shown in FIG. 10 to which the diaphragm was bonded and fixed. It is sectional drawing of the speaker main body which concerns on the modification of 1st Embodiment of this invention. It is sectional drawing of the speaker main body which concerns on the other modification of 1st Embodiment of this invention. It is the perspective view which showed the speaker main body which concerns on 2nd Embodiment of this invention. It is sectional drawing which cut | disconnected the speaker main body in the plane p2 of FIG. It is a top view of the speaker main body shown in FIG. It is a bottom view of the speaker main body shown in FIG. It is a perspective view of the ceramic green sheet laminated | stacked in the manufacturing process of the speaker main body shown in FIG. It is a perspective view of the ceramic green sheet laminated body which laminated | stacked and crimped | bonded the ceramic green sheet shown in FIG. It is a perspective view of the ceramic laminated body formed by baking the ceramic green sheet laminated body shown in FIG. It is a perspective view of the ceramic laminated body shown in FIG. 20 with which the piezoelectric / electrostrictive layer laminated body was formed. It is a perspective view of the ceramic laminated body shown in FIG. 21 after a cutting process. It is a perspective view of the ceramic laminated body shown in FIG. 22 to which the diaphragm was bonded and fixed. It is the perspective view which showed the speaker main body which concerns on 3rd Embodiment of this invention. It is sectional drawing which cut | disconnected the speaker main body in the plane p3 of FIG. It is a top view of the speaker main body shown in FIG. It is a bottom view of the speaker main body shown in FIG. It is the perspective view which showed the speaker main body which concerns on 4th Embodiment of this invention. It is sectional drawing which cut | disconnected the speaker main body in the plane p4 of FIG. It is a top view of the speaker main body shown in FIG. It is a bottom view of the speaker main body shown in FIG. It is the perspective view which showed the speaker main body which concerns on 5th Embodiment of this invention. It is sectional drawing which cut | disconnected the speaker main body in the plane p5 of FIG. It is a top view of the speaker main body shown in FIG. It is a bottom view of the speaker main body shown in FIG.

Explanation of symbols

  110: Enclosure, 120, 220, 320, 420, 520 ... Speaker body, 132, 232, 332a, 332b, 332c, 432 ... Drive plate, 141, 241, 341a, 341b, 341c, 441, 541 ... Piezoelectric / electric Strain elements 142, 242, 342, 442a, 442b, 542 ... diaphragm (diaphragm part), 133, 233, 333, 433, 533 ... fixed part, 135, 235, 335a, 335b, 335c, 335d, 435a, 435b, 435c, 535 ... cavity

Claims (10)

A piezoelectric / electrostrictive element having a shape having an internal space inside;
A diaphragm for radiating sound waves to the outside;
A medium enclosed in a cavity defined by at least the internal space of the piezoelectric / electrostrictive element and the diaphragm, and transmitting the vibration of the piezoelectric / electrostrictive element to the diaphragm;
Speaker equipped with. The speaker according to claim 1 ,
The speaker according to claim 1, wherein an internal space of the piezoelectric / electrostrictive element is partitioned into a plurality of spaces. The speaker according to claim 1 or 2 ,
The speaker, wherein the medium is a liquid. The speaker according to claim 1 or 2 ,
The speaker, wherein the medium is a gel. The speaker according to any one of claims 1 to 4 ,
An ultrasonic signal amplitude-modulated with an audio signal as a drive signal is supplied to the piezoelectric / electrostrictive element. A giant magnetostrictive element using a giant magnetostrictive material having a shape having an internal space inside,
A diaphragm for radiating sound waves to the outside;
A medium enclosed in a cavity defined by at least an internal space of the giant magnetostrictive element and the diaphragm, and transmitting the vibration of the giant magnetostrictive element to the diaphragm;
Speaker equipped with. The speaker according to claim 6 , wherein
An internal space of the giant magnetostrictive element is partitioned into a plurality of spaces. The speaker according to claim 6 or 7 ,
The speaker, wherein the medium is a liquid. The speaker according to claim 6 or 7 ,
The speaker, wherein the medium is a gel. The speaker according to any one of claims 6 to 9 ,
The speaker according to claim 1, wherein an ultrasonic signal amplitude-modulated with an audio signal is supplied as a drive signal to the giant magnetostrictive element.

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