JP2017118424A - Acoustic generator, acoustic generation device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic generator capable of improving a sound pressure in a reproduction frequency band, especially, a sound pressure at a lower side of the reproduction frequency band, an acoustic generation device and an electronic apparatus.SOLUTION: An acoustic generator 10 comprises: a diaphragm 2 in a shape having a length direction and a width direction; multiple piezoelectric elements 1 which are arrayed on the diaphragm 2 in the length direction; a frame member 3 which supports an outer peripheral part of the diaphragm 2; and a wiring member 5 for electrically connecting terminals 4 that are provided on a principal plane of the frame member 3, with the multiple piezoelectric elements 1. Each of the multiple piezoelectric elements 1 is formed to have a length direction and the width direction and arrayed in such a manner that the length direction of the multiple piezoelectric elements 1 is turned in the length direction of the diaphragm 2, and the wiring member 5 is disposed over the multiple piezoelectric elements 1 and the terminals 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sound generator, a sound generator, and an electronic device.

  An acoustic generator is known that includes a diaphragm, a piezoelectric element attached on the diaphragm, and a frame member that supports the outer periphery of the diaphragm (see, for example, Patent Document 1). This sound generator vibrates a diaphragm by applying a voltage to a piezoelectric element to vibrate, and outputs sound by actively utilizing resonance of such vibration. For example, such a sound generator is housed in a housing and used as a sound generator, and is used by being incorporated in a small electronic device such as a mobile computing device.

International Publication No. 2011/162002

  Such a sound generator is required to further increase the sound pressure in the reproduction frequency band, and in particular, to further increase the sound pressure on the low frequency side of the reproduction frequency band.

  The present invention has been made in view of the above circumstances, and provides a sound generator, a sound generator, and an electronic device that can improve sound pressure in a reproduction frequency band, particularly sound pressure in a low frequency side of the reproduction frequency band. For the purpose.

  The acoustic generator according to the present invention supports a diaphragm having a longitudinal direction and a transverse direction, a plurality of piezoelectric elements arranged on the diaphragm along the longitudinal direction, and an outer peripheral portion of the diaphragm. And a wiring member that electrically connects the terminals provided on the main surface of the frame member and the plurality of piezoelectric elements, the plurality of piezoelectric elements having a longitudinal direction and a short direction. The wiring elements are arranged such that the longitudinal direction of the plurality of piezoelectric elements faces the longitudinal direction of the diaphragm, and the wiring member extends over the plurality of piezoelectric elements and the terminals. It is arranged.

  According to another aspect of the present invention, there is provided a sound generation apparatus including the above-described sound generator and a housing that houses the sound generator.

  According to another aspect of the invention, there is provided an electronic apparatus comprising: the above-described acoustic generator; an electronic circuit connected to the piezoelectric element that constitutes the acoustic generator; and a housing that houses the acoustic generator and the electronic circuit. It is characterized by being.

  According to the sound generator of the present invention, the sound pressure in the reproduction frequency band can be improved, and in particular, the sound pressure on the low frequency side of the reproduction frequency band can be improved.

  Moreover, according to the sound generator and the electronic device of the present invention, the sound generator and the electronic device having excellent acoustic performance can be realized because the sound generator has an improved sound pressure.

(A) is a schematic plan view which shows an example of the acoustic generator of this embodiment, (b) is the schematic sectional drawing which cut | disconnected the piezoelectric element shown to (a) by the AA line. (A) is a schematic plan view which shows the other example of the sound generator of this embodiment, (b) is a schematic sectional drawing cut | disconnected by the BB line shown to (a), (c) shows to (a). It is the schematic sectional drawing cut | disconnected by CC line. It is a schematic plan view which shows the other example of the acoustic generator of this embodiment. It is a schematic plan view which shows the other example of the acoustic generator of this embodiment. It is a schematic plan view which shows the other example of the acoustic generator of this embodiment. It is a schematic plan view which shows the other example of the acoustic generator of this embodiment. It is a block diagram which shows the structure of an example of the sound generator of this embodiment. It is a block diagram which shows the structure of an example of the electronic device of this embodiment.

  Hereinafter, an example of the sound generator of the present embodiment will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

  FIG. 1A is a schematic plan view showing an example of the acoustic generator of this embodiment, and FIG. 1B is a schematic cross-sectional view of the piezoelectric element shown in FIG. 1A taken along line AA. An acoustic generator 10 shown in FIG. 1 includes a diaphragm 2 having a longitudinal direction and a transverse direction, a plurality of piezoelectric elements 1 arranged on the diaphragm 2 along the longitudinal direction, and an outer periphery of the diaphragm 2. And a wiring member 5 that electrically connects the terminals 4 provided on the main surface of the frame member 3 and the plurality of piezoelectric elements 1, and the plurality of piezoelectric elements 1 are long in length. The wiring member 5 is arranged so that the longitudinal direction of the plurality of piezoelectric elements 1 faces the longitudinal direction of the diaphragm 2, and the wiring member 5 is connected to the plurality of piezoelectric elements 1 and terminals. 4 is arranged so as to straddle 4.

  A plurality of piezoelectric elements 1 are used as an exciter constituting the acoustic generator 10. Each of the plurality of piezoelectric elements 1 has a shape having a longitudinal direction and a short direction, and is rectangular in the example shown in the figure. For example, as shown in FIG. 1B, the piezoelectric element 1 includes a laminated body 13 in which piezoelectric layers 11 and internal electrode layers 12 are alternately laminated, and surface electrodes provided on the upper and lower surfaces of the laminated body 13. 14 and an external electrode 15 provided on the side surface from which the internal electrode layer 12 is derived.

  The piezoelectric layer 11 constituting the piezoelectric element 1 is provided with ceramics having piezoelectric characteristics. Conventionally used piezoelectric materials such as lead zirconate titanate, lithium niobate, lithium tantalate, bismuth layered compounds, tungsten bronze structure compounds, etc. as such ceramics Ceramics can be used. The thickness of one layer of the piezoelectric layer 11 is preferably set to, for example, 0.01 to 0.1 mm in order to drive at a low voltage. In order to obtain a large bending vibration, it is preferable to have a piezoelectric constant d31 of 200 pm / V or more.

Further, as shown in FIG. 1B, the internal electrode layer 12 constituting the piezoelectric element 1 is provided by simultaneous firing with the ceramic constituting the piezoelectric layer 11, and the first internal electrode layer 121 and It consists of the second internal electrode layer 122. The piezoelectric layers 11 are alternately stacked to sandwich the piezoelectric layers 11 from above and below, and the first internal electrode layer 121 and the second internal electrode layer 122 are arranged in the stacking order, so that they are sandwiched between them. A drive voltage is applied to the piezoelectric layer 11 thus formed. In FIG. 1A, the first internal electrode layer 121 is led out to the side surface of the multilayer body 13 located on the lower side of the multilayer body 13, and the second internal electrode layer 122 is the paper plane of the multilayer body 13. It is derived | led-out by the side surface located in an upper side.

  As a material constituting the internal electrode layer 12, various metal materials can be used. For example, a conductor containing silver or silver-palladium as a main component that can be fired at a low temperature, or a conductor containing copper, platinum, or the like can be used. However, a ceramic component or a glass component may be contained therein. When the internal electrode layer 12 is formed of a material containing a metal component composed of silver and palladium and a ceramic component that forms the piezoelectric layer 11, the piezoelectric layer 11 and the internal electrode layer 12 can be fired at the time of firing. Since the stress due to the shrinkage difference can be reduced, the piezoelectric element 1 having no stacking failure can be obtained.

  The piezoelectric element 1 shown in FIG. 1 has a unimorph structure, but may have a bimorph structure. That is, as a piezoelectric element, the direction of polarization with respect to the direction of an electric field applied at a certain moment is reversed between one side (first main surface side) and the other side (second main surface side) in the thickness direction. It may be a polarized bimorph structure. Thereby, while contributing to thickness reduction, the diaphragm 2 can be vibrated efficiently with little energy.

  The diaphragm 2 is made of various materials such as resin and metal, and has a shape having a longitudinal direction and a transverse direction, and has a rectangular shape in the example shown in the figure. For example, a rectangular diaphragm 2 made of a resin film such as polyethylene or polyimide having a thickness of 10 to 200 μm and having a main surface of 8 to 28 mm in the vertical direction (short direction) and 28 to 60 mm in the horizontal direction (longitudinal direction). Can be used.

  The plurality of piezoelectric elements 1 are arranged on a diaphragm 2 having a longitudinal direction and a short-side direction so as to face the longitudinal direction of the diaphragm 2 and are attached with an adhesive or the like. The plurality of piezoelectric elements 1 vibrate upon application of voltage to vibrate the diaphragm 2. Specifically, each main surface of the plurality of piezoelectric elements 1 is bonded to the main surface of the diaphragm 2 with an adhesive such as an epoxy resin. The vibration plate 2 vibrates together with the plurality of piezoelectric elements 1 by the vibration of the plurality of piezoelectric elements 1.

  At this time, although not shown in FIG. 1, a wiring member 5 to be described later is electrically connected to the surface electrode 14 of the piezoelectric element 1 using solder or a conductive adhesive, and the wiring member 5 is interposed via the wiring member 5. An electric signal is input to the piezoelectric element 1. When a voltage is applied to the piezoelectric element 1, at a certain moment, the piezoelectric layer 11 on the lower surface side of the piezoelectric element 1 that is bonded to the diaphragm 2 contracts in an in-plane direction perpendicular to the stacking direction, and the piezoelectric element The piezoelectric layer 11 on the upper surface side of 1 is deformed so as to extend in an in-plane direction perpendicular to the stacking direction, and the whole is bent. Therefore, by applying an AC signal to the piezoelectric element 1, the piezoelectric element 1 can bend and vibrate, and the diaphragm 2 can be bent.

  A frame member 3 is provided so as to support the outer peripheral portion of the diaphragm 2. The frame member 3 is bonded to the outer peripheral portion of the diaphragm 2 with an adhesive, for example. The diaphragm 2 is supported by the frame member 3 in a state where tension is applied in the frame of the frame member 3, and a portion not supported by the frame member 3 can freely vibrate.

  Here, the thickness and material of the frame member 3 are not particularly limited, and various materials such as metal, resin, and glass can be used. For example, a stainless steel member having a thickness of 0.1 to 5.0 mm can be suitably used as the frame member 3 because of its excellent mechanical strength and corrosion resistance. Moreover, as a width | variety of the frame member 3, the thing of 1.2-10.0 mm is used, for example.

A terminal 4 is provided on the main surface of the frame member 3 (an upper surface located on the side opposite to the side facing the diaphragm 2). The terminal 4 is a so-called electrode terminal serving as a connection point with an external circuit, and is provided in accordance with the number of wiring members 5. FIG. 1 illustrates a case where a plurality (two in this case) of terminals 4 are provided on the frame member 3. In FIG. 1, the wiring member 5 is made of a metal plate, and the end of the wiring member 5 is wide, and the end 4 of the wiring member 5 serves as a connection point with an external circuit. Doubles as In other words, the wiring member 5 and the terminal 4 are integrally formed. Therefore, the end of the wiring member 5 can be used as the terminal 4, and the terminal 4 does not have to be provided separately. As described above, the wiring member 5 and the terminal 4 may be electrically connected to each other by the configuration in which the wiring member 5 and the terminal 4 are integrally formed.

  Here, when the frame member 3 and the terminal 4 are made of a metal material, the terminal 4 is preferably provided on the main surface of the frame member 3 via an intermediate layer or substrate made of an insulating material. When the terminal 4 is made of a metal material and the frame member 3 is made of an insulating material, the intermediate layer or the substrate may not be interposed. The intermediate layer may be an adhesive layer made of a resin that is thick enough to ensure insulation. The intermediate layer may have a structure composed of a plurality of layers. Further, a glass epoxy substrate or the like can be used as the substrate.

  The wiring member 5 is electrically connected to the plurality of piezoelectric elements 1 and is also electrically connected to the terminals 4. Here, the wiring member 5 is disposed so as to straddle the plurality of piezoelectric elements 1 and the terminals 4. In other words, one wiring member 5 is connected to each of the piezoelectric elements 1 and the terminals 4 of the plurality of piezoelectric elements 1. Note that the wiring member 5 is disposed so as to straddle the plurality of piezoelectric elements 1 and the terminals 4 as described above includes a configuration in which the wiring members 5 and the terminals 4 are integrally formed. I mean.

  As the wiring member 5, a lead wire in which the outer periphery of the side surface of the conductor is covered with an insulating material, a flexible substrate (FPC), a thin metal plate, or the like can be used. In addition, in the case of a lead wire and a flexible substrate, it is comprised so that a conductor may be partially exposed so that electrical connection with the desired surface electrode 14 in each piezoelectric element 1 can be taken.

  According to the acoustic generator 10 of the present embodiment, the plurality of piezoelectric elements 1 have a shape having a longitudinal direction and a short direction, and the longitudinal direction of the plurality of piezoelectric elements 1 faces the longitudinal direction of the diaphragm 2. Thus, the lowest resonance frequency of the acoustic generator 10 can be lowered. Therefore, the reproduction frequency band can be expanded to the low frequency side, and the sound pressure on the low frequency side of the reproduction frequency band can be improved. Further, since the wiring member 5 is disposed so as to extend over the plurality of piezoelectric elements 1 and the terminals 4, it is possible to improve the sound quality of the sound generator 10 by suppressing peaks and dip due to the damper effect. In addition, since the number of wiring members 5 and the number of connection points (terminals 4) with the frame member 3 can be minimized, variations in frequency characteristics among products can be suppressed, and the sound quality of the sound generator 10 can be improved.

  2A is a schematic plan view showing another example of the sound generator of the present embodiment, FIG. 2B is a schematic cross-sectional view taken along line BB shown in FIG. 2A, and FIG. FIG. 3C is a schematic cross-sectional view taken along line CC shown in FIG.

  Although not specifically shown, the piezoelectric element 1 ′ shown in FIG. 2 is a bimorph piezoelectric element. The laminated body 13 constituting the piezoelectric element 1 ′ has a region on one main surface side and a region on the other main surface side. The region on the one main surface side and the region on the other main surface side in the multilayer body 13 have, for example, behaviors in which the polarization directions of the piezoelectric layer 11 included in these regions are symmetric, and the expansion / contraction state during driving is different. It is in the relationship which shows. Usually, the boundary between the region on the one main surface side and the region on the other main surface side is located in the central portion in the thickness direction.

In FIG. 2, the first internal electrode layer 121 is led out to the side surface of the multilayer body 13 located on the right side of the multilayer body 13 and the second internal electrode layer 122 is disposed on the side surface of the multilayer body 13 located on the left side of the paper surface. Has been derived. Of the plurality of surface electrodes 14, the first surface electrode 141 having a relatively large area is electrically connected to the second internal electrode layer 122. The second surface electrode 142 having a relatively small area is electrically connected to the first internal electrode layer 121. In addition, in the manufacturing process, the second surface electrode 142 includes an electrode electrically connected to the first internal electrode layer 121 in the region on the one main surface side, and a first electrode in the region on the other main surface side. The internal electrode layer 121 and the electrode electrically connected to each other can be obtained by joining the electrodes after polarization of the piezoelectric layer 11. Thereby, it can be set as the bimorph structure which has the area | region of the one main surface side, and the area | region of the other main surface side.

  One of the pair of wiring members 5 is electrically connected to the second surface electrode 142 of each piezoelectric element 1 ′ via a conductive bonding material 6 such as solder or conductive adhesive, and the pair of wiring members The other of the members 5 is electrically connected to the first surface electrode 141 of each piezoelectric element 1 ′.

  As shown in FIG. 2, a plurality of surface electrodes 14 (first surface electrode 141, second surface electrode 142) are provided on the respective surfaces of the plurality of piezoelectric elements 1 ′, and the plurality of the plurality of surface electrodes 14 are provided. It is preferable that the coating layer 7 made of an insulating resin is provided so as to cover at least one of the surface electrodes 14 (the first surface electrode 141 and the second surface electrode 142). As the coating layer 7, an insulating resin such as a silicon resin or an epoxy resin can be used.

  Here, to cover at least one surface electrode 14 of the plurality of surface electrodes 14 (first surface electrode 141, second surface electrode 142), the coating layer 7 includes at least one surface electrode 14. It also includes being provided so as to cover at least a part. In the example shown in FIG. 2, the covering layer 7 is provided so as to cover a part other than the portion joined to the wiring member 5 by the conductive bonding material 6 of the second surface electrode 142 in each piezoelectric element 1 ′. And a covering layer so as to cover a part other than the portion bonded to the wiring member 5 with the conductive bonding material 6 of the first surface electrode 141 in one of the two piezoelectric elements 1 ′. 7 is provided. The covering layer 7 is, for example, approximately the same thickness as the conductive bonding material 6 and is preferably in contact with the wiring member 5.

  By setting it as such a structure, since the coating layer 7 can suppress the vibration of the wiring member 5 and can suppress the fall of the sound quality which arises by the vibration of the wiring member 5, a sound quality can be improved.

  The example shown in FIG. 2 is a configuration in which the coating layer 7 covers a part of the surface electrode 14 other than the portion bonded to the wiring member 5 by the conductive bonding material 6. The configuration is not limited thereto, and the covering layer 7 may cover the entire region other than the portion of the surface electrode 14 that is bonded to the wiring member 5 by the conductive bonding material 6. Thereby, the effect which suppresses the vibration of the wiring member 5 can be heightened.

  Here, as shown in FIG. 3, the wiring member 5 preferably has a shape that expands and contracts in the longitudinal direction. With such a configuration, the wiring member 5 expands and contracts due to vibration of the piezoelectric element 1 ′. Therefore, the vibration of the piezoelectric element 1 ′ is hardly inhibited. Thereby, the sound pressure of the sound generator 10 can be further improved.

  Specifically, as shown in FIG. 3, the wiring member 5 is made of a metal plate, and slits 51 that are alternately provided from both side surfaces in the longitudinal direction toward the width direction, and slits 51 and slits that are adjacent in the longitudinal direction. It is good to have a structure having a hole 52 provided so as to extend in the width direction. Such a wiring member 5 can be easily obtained by processing a metal plate, has sufficient stretchability, is difficult to twist, and has good durability.

  The plurality of piezoelectric elements 1, 1 ′ are arranged so that the longitudinal direction of the plurality of piezoelectric elements 1, 1 ′ faces the longitudinal direction of the diaphragm 2, as shown in FIG. 4. The plurality of piezoelectric elements 1, 1 ′ are not necessarily parallel to the longitudinal direction of the diaphragm 2, and the longitudinal direction of the piezoelectric elements 1, 1 ′ is within a range of plus or minus 15 degrees with respect to the longitudinal direction of the diaphragm 2. It may be tilted at.

  The plurality of piezoelectric elements 1, 1 ′ are arranged along the longitudinal direction of the diaphragm 2, but as shown in FIG. 5, the adjacent piezoelectric elements 1, 1 ′ are the piezoelectric element 1, It may be arranged so as to be shifted by a distance within a range of 20% of the width of 1 ′.

  Moreover, although the example shown in FIGS. 1-5 has shown the structure which has arrange | positioned the two piezoelectric elements 1 in a line along a longitudinal direction, as shown in FIG. Each may be arranged in two rows along the longitudinal direction, or more piezoelectric elements 1 may be arranged along the longitudinal direction, or more rows may be arranged.

  The sound generator 10 may further include a resin layer (not shown) provided so as to cover the surfaces of the piezoelectric element 1 and the diaphragm 2 within the frame of the frame member 3. This resin layer is preferably provided using, for example, an acrylic resin so that the Young's modulus is in the range of 1 MPa to 1 GPa, for example. This resin layer is not necessarily provided until the surface of the piezoelectric element 1 is covered, but is provided until the surface of the piezoelectric element 1 is covered, and further, the piezoelectric element 1 is embedded in the resin layer, A moderate damping effect can be induced. Therefore, the resonance phenomenon can be suppressed and the peak or dip in the frequency characteristic of the sound pressure can be suppressed to a small value.

  Further, in this example, a case where a plurality of piezoelectric elements 1 are provided on one main surface of the diaphragm 2 is shown, but a plurality of piezoelectric elements 1 may be provided on both main surfaces of the diaphragm 2.

  Next, an example of the manufacturing method of the acoustic generator 10 of this embodiment is demonstrated.

  First, the piezoelectric elements 1 and 1 'are prepared.

  A binder, a dispersant, a plasticizer, and a solvent are kneaded with the piezoelectric material powder constituting the piezoelectric layer 11 to produce a slurry. As the piezoelectric material, any of lead-based and non-lead-based materials can be used.

  Next, the obtained slurry can be formed into a sheet to obtain a green sheet, and an internal electrode layer pattern is formed by printing an internal electrode layer conductive paste on the green sheet. For example, four formed green sheets are laminated, and only the green sheet is laminated on the uppermost layer to produce a laminated molded body.

  Next, the laminate 13 can be obtained by degreasing, firing, and cutting the laminate compact to a predetermined size. The laminated body 13 processes an outer peripheral part as needed, prints the paste of the surface electrode 14 on the main surface of the piezoelectric layer 11 of the laminated body 13 in the laminating direction, and then continues to both sides of the laminated body 13 in the longitudinal direction. The paste of the external electrode 15 is printed on the electrode, and the electrode is baked at a predetermined temperature.

  Finally, in order to impart piezoelectricity to the piezoelectric element, a DC voltage is applied through the surface electrode 14 or the external electrode 15 to polarize the piezoelectric layer 11 of the piezoelectric elements 1, 1 ′, so that a stacked piezoelectric element is obtained. Elements 1, 1 'can be obtained.

Next, a film to be the diaphragm 2 is prepared, and the outer peripheral portion of the film is fixed to the frame member 3 in a state where tension is applied to the film. At this time, an adhesive is provided between the frame member 3 and the diaphragm 2. For example, after applying an adhesive made of a UV curable resin to the main surface of the diaphragm in a tensioned state using a method such as printing or a dispenser in the shape of the frame member, the frame member 3 is pressed and UV (ultraviolet light) is applied. ) To cure.

  Next, a predetermined number of piezoelectric elements 1, 1 ′ are bonded to the diaphragm 2 provided with the frame member 3 on the outer peripheral portion by the method described above. Specifically, an adhesive is applied to the diaphragm 2 (resin film), the piezoelectric elements 1 and 1 ′ are pressed so as to sandwich the adhesive, and then the adhesive is irradiated with heat or ultraviolet rays. To cure. The thickness of the adhesive layer between the piezoelectric elements 1, 1 ′ and the diaphragm 2 is 20 μm or less, preferably 10 μm or less. Thus, when the thickness of the adhesive layer 21 is 20 μm or less, the vibration of the piezoelectric element is easily transmitted to the film. As the adhesive, known materials such as an epoxy resin, a silicon resin, and a polyester resin can be used. As a method for curing the resin used for the adhesive, the vibrating body can be produced by using any of thermosetting, photocuring, anaerobic curing, and the like.

  Further, the wiring member 5 is joined to the plurality of piezoelectric elements 1, 1 ′ and the terminals 4 provided on the frame member 3. Examples of the bonding method include a method in which a conductive bonding material 6 adhesive is applied to the surface electrode 14 of the piezoelectric elements 1, 1 ′, the wiring member 5 is pressed, and cured by heat.

  Here, when the wiring member 5 is made of a metal plate, the end portion can be used as the terminal 4, and the terminal 4 does not have to be provided separately. At this time, in order to use the end of the wiring member 5 as a terminal, the frame member 3 may be bonded with an adhesive or a double-sided tape. In addition, the end of the wiring member 5 is widened so that it can be easily used as the terminal 4, or the slits 51 that are alternately provided from both side surfaces in the longitudinal direction toward the width direction, and slits 51 that are adjacent in the longitudinal direction In order to have a structure having a hole 52 provided so as to extend in the width direction between the slit 51 and the slit 51, press working or etching may be used.

  Then, if necessary, the acoustic generator 10 of this embodiment can be obtained by pouring resin inside the frame member 3, completely embedding the piezoelectric elements 1, 1 ', and curing the resin layer.

  Next, an example of the sound generator of this embodiment will be described.

  The sound generation device 100 is a sound generation device such as a so-called speaker. As shown in FIG. 7, the sound generation device 100 of this example includes a sound generator 10 and a housing 20 that houses the sound generator 10. Note that a part of the housing 20 may be the diaphragm 2 constituting the acoustic generator 10, and that the housing 20 accommodates the acoustic generator 10 means that a part of the acoustic generator 10 (piezoelectric element 1). ) Is also included.

  The housing 20 resonates the sound generated by the sound generator 10 inside, and radiates sound to the outside from an opening (not shown) formed in the housing 20. The housing 20 can be formed using various materials such as metals such as aluminum and magnesium alloys, resins such as polycarbonate, and wood. By having such a housing | casing 20, the sound pressure in a low frequency band can be raised, for example.

  Such a sound generator 100 can be used alone as a speaker, and can be suitably incorporated into a portable terminal, a thin television, a tablet terminal, or the like, as will be described later. Moreover, it can also be incorporated into home appliances that have not been prioritized in terms of sound quality, such as refrigerators, microwave ovens, vacuum cleaners, and washing machines.

  Since the sound generator of this embodiment described above is configured using a sound generator with improved sound pressure in the reproduction frequency band, a sound generator excellent in sound performance can be realized.

  Next, an example of the electronic apparatus of this embodiment will be described.

  As shown in FIG. 8, the electronic device 50 of the present embodiment includes an acoustic generator 10, an electronic circuit 60 connected to the acoustic generator 10, and a housing 70 that houses the electronic circuit 60 and the acoustic generator 10. And has a function of generating sound from the sound generator 10. In addition, as the electronic device 50, not only the acoustic generator 10 is accommodated in the casing 70 as it is, but also the acoustic generator 100 that accommodates the acoustic generator 10 (consisting of the acoustic generator 10 and the casing 5). Is included in the housing 70. Further, a part of the housing 70 may be the diaphragm 2 constituting the sound generator 10.

  The electronic device 50 includes an electronic circuit 60. Examples of the electronic circuit 60 include a circuit for processing image information to be displayed on a display and audio information transmitted by a portable terminal, a communication circuit, and the like. At least one of these circuits may be included, or all the circuits may be included. Further, it may be a circuit having other functions. Furthermore, you may have a some electronic circuit. The electronic circuit 60 shown in the figure includes a controller 60a, a transmission / reception unit 60b, a key input unit 60c, and a microphone input unit 60d. The electronic circuit 60 is connected to the sound generator 10 and has a function of outputting an audio signal to the sound generator 10. The sound generator 10 generates sound based on the sound signal input from the electronic circuit 60.

  Further, the electronic device 50 includes a display unit 50a, an antenna 50b, and the sound generator 10, and includes a housing 70 that accommodates these devices. Although FIG. 8 shows a state in which each device including the controller 60a is accommodated in one casing, the accommodation form of each device is not limited. In the present embodiment, it is only necessary that at least the electronic circuit 60 and the sound generator 10 are accommodated in one housing 70.

  The controller 60 a is a control unit of the electronic device 50. The transmission / reception unit 60b transmits / receives data via the antenna 50b based on the control of the controller 60a. The key input unit 60c is an input device of the electronic device 50 and accepts a key input operation by an operator. The key input unit 60 c may be a button-like key or a touch panel integrated with the display unit 50. The microphone input unit 60d is also an input device of the electronic device 50, and receives a voice input operation by an operator. The display unit 50a is a display output device of the electronic device 50, and outputs display information based on the control of the controller 60a.

  The sound generator 10 operates as a sound output device in the electronic device 60. The sound generator 10 is connected to the controller 60a of the electronic circuit 60, and emits sound upon application of a voltage controlled by the controller 60a.

  In FIG. 8, the electronic device is described as a portable terminal device. However, the electronic device is not limited to the type of the electronic device, and may be applied to various consumer devices having a function of emitting sound. For example, flat-screen televisions and car audio devices can of course be used for products having a function of generating sound, for example, various products such as vacuum cleaners, washing machines, refrigerators, microwave ovens, and the like.

Since the electronic device of the present embodiment described above is configured using an acoustic generator with improved sound pressure in the reproduction frequency band, an electronic device with excellent acoustic performance can be realized.

DESCRIPTION OF SYMBOLS 10 Sound generator 1, 1 'Piezoelectric element 11 Piezoelectric layer 12 Internal electrode layer 13 Laminated body 14 Surface electrode 15 External electrode 2 Diaphragm 3 Frame member 4 Terminal 5 Wiring member 6 Conductive joining material 7 Covering layer 100 Sound generator 50 Electronic equipment 60 Electronic circuit 20, 70 Housing

Claims (6)

  A diaphragm having a shape having a longitudinal direction and a short direction, a plurality of piezoelectric elements arranged on the diaphragm along the longitudinal direction, a frame member that supports an outer peripheral portion of the diaphragm, and the frame member And a wiring member for electrically connecting the plurality of piezoelectric elements to each other, the plurality of piezoelectric elements having a longitudinal direction and a short direction, The piezoelectric elements are arranged so that the longitudinal direction of the piezoelectric elements faces the longitudinal direction of the diaphragm, and the wiring member is disposed so as to straddle the plurality of piezoelectric elements and the terminals. Sound generator.   A plurality of surface electrodes are provided on the respective surfaces of the plurality of piezoelectric elements, and a coating layer made of an insulating resin is provided so as to cover at least one of the plurality of surface electrodes. The sound generator according to claim 1.   The acoustic generator according to claim 1, wherein the wiring member has a shape that expands and contracts in the longitudinal direction.   The wiring member includes slits alternately provided from both side surfaces in the longitudinal direction toward the width direction, and holes provided so as to extend in the width direction between the slits adjacent to each other in the longitudinal direction. The sound generator according to claim 3, comprising:   An acoustic generator comprising: the acoustic generator according to any one of claims 1 to 4; and a housing that accommodates the acoustic generator. The sound generator according to any one of claims 1 to 4,
An electronic circuit connected to the acoustic generator;
An electronic device comprising the electronic circuit and a housing for housing the acoustic generator.

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