transducer

Abstract

The present invention provides a transducer, comprising: a piezoelectric element (10), which has a piezoelectric film (13) sandwiched by a pair of electrodes (11, 12); a film body (15), which has a vibration film (16) capable of displacement in the film thickness direction, and the piezoelectric element is stacked on the vibration film (16); a packaging body (60), which has an internal space (90) for accommodating the piezoelectric element (10) and the film body (15); and an abutment pad (80), which is arranged in the internal space (90) and, when the vibration film (16) is displaced in the film thickness direction, limits the displacement of the vibration film (16) by abutting against the piezoelectric element (10) or the vibration film (16).

Description

Technical Field

[0001] The present invention relates to transducers. Background Art

[0002] Transducers that transmit or receive sound waves or ultrasonic waves are well known. For example, transducers can be used as speakers that transmit sound waves and can be installed in headphones or wearable devices.

[0003] For example, a sound generating device suitable for headphones is disclosed in Patent Document 1. The sound generating device includes a coil that generates a magnetic field and a magnet that interacts with the magnetic field generated by the coil to vibrate a diaphragm.

[0004] Speakers using coils and magnets require high drive voltages, resulting in increased power consumption. Consequently, speakers utilizing piezoelectric elements, consisting of a piezoelectric film sandwiched between a pair of electrodes, have also attracted attention (see, for example, Patent Document 2). These speakers are manufactured using MEMS (Micro Electro Mechanical Systems), a semiconductor manufacturing technology that enables fine processing.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-170592.

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2012-105170. Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, MEMS speakers have a delicate shape and are therefore prone to being fragile, potentially breaking due to external impacts.

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a transducer capable of suppressing the occurrence of damage.

[0012] Technical means to solve the problem

[0013] In order to solve such problems, the present invention provides a piezoelectric element, which includes: a piezoelectric element having a pair of electrodes and a piezoelectric film sandwiched by the pair of electrodes; a film body having a vibration film capable of displacement in the film thickness direction, and the piezoelectric element stacked on the vibration film; a packaging body having an internal space for accommodating the piezoelectric element and the film body; and an abutment component, which is arranged in the internal space and, when the vibration film is displaced in the film thickness direction, limits the displacement of the vibration film by abutting against the piezoelectric element or the vibration film.

[0014] In addition, the present invention provides a transducer, which includes: a membrane supporting portion, which has a cylindrical inner circumferential surface forming a hollow portion; a vibrating membrane, which is connected to the inner circumferential surface over the entire circumference of the inner circumferential surface and can be displaced in the membrane thickness direction; a piezoelectric element, which is stacked on the vibrating membrane and has a pair of electrodes and a piezoelectric membrane sandwiched between the pair of electrodes; and a dividing gap, which penetrates the vibrating body formed by stacking the vibrating membrane and the piezoelectric element in the thickness direction, and divides the vibrating body into multiple vibration areas, the inner circumferential surface has a polygonal shape connecting multiple planar portions via chamfered corners, and the dividing gap has: a main gap portion extending from the center of the vibrating membrane to the corner; and a sub-gap portion extending from the connecting portion connecting the corner and the planar portion to the end portion on the corner side of the main gap portion.

[0015] In addition, the present invention provides a transducer, which includes: a membrane support portion, which has a cylindrical inner circumferential surface forming a hollow portion; a vibrating membrane, which is connected to the inner circumferential surface over the entire circumference of the inner circumferential surface and can be displaced in the membrane thickness direction; a piezoelectric element, which is stacked on the vibrating membrane and has a pair of electrodes and a piezoelectric membrane sandwiched between the pair of electrodes; and a dividing gap, which penetrates the vibrating body formed by stacking the vibrating membrane and the piezoelectric element in the thickness direction, dividing the vibrating body into multiple vibration areas, the inner circumferential surface has a polygonal shape connecting multiple planar portions via corners, the dividing gap extends from the center of the vibrating membrane to the corners, the piezoelectric element has a piezoelectric gap, the piezoelectric gap penetrates the piezoelectric element in the thickness direction, and extends from the planar portion to the dividing gap along the perpendicular direction of the planar portion.

[0016] Effects of the Invention

[0017] According to the present invention, a transducer capable of suppressing the occurrence of damage can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view showing the transducer according to the first embodiment.

[0019] Figure 2 It is a plan view showing the transducer according to the first embodiment.

[0020] Figure 3 It is a cross-sectional view showing the acoustic chip according to the first embodiment.

[0021] Figure 4 It is a plan view showing the acoustic chip according to the first embodiment.

[0022] Figure 5A It is a cross-sectional view illustrating the configuration of module electrodes.

[0023] Figure 5B It is a cross-sectional view illustrating the configuration of module electrodes.

[0024] Figure 6A It is a cross-sectional view illustrating the mounting form of electronic components.

[0025] Figure 6B It is a cross-sectional view illustrating the mounting form of electronic components.

[0026] Figure 6C It is a cross-sectional view illustrating the mounting form of electronic components.

[0027] Figure 7A It is a cross-sectional view illustrating the form of the package.

[0028] Figure 7B It is a cross-sectional view illustrating the form of the package.

[0029] Figure 7C It is a cross-sectional view illustrating the form of the package.

[0030] Figure 8A It is a cross-sectional view illustrating the sealing structure between the package and the acoustic chip.

[0031] Figure 8B It is a cross-sectional view illustrating a sheet member that closes the first through-hole and the second through-hole.

[0032] Figure 8C It is a cross-sectional view illustrating the form of the first through hole.

[0033] Figure 9A It is a cross-sectional view illustrating a groove portion formed in a package.

[0034] Figure 9B It is a cross-sectional view illustrating a groove portion formed in a package.

[0035] Figure 9C It is a cross-sectional view illustrating a groove portion formed in a package.

[0036] Figure 10 It is a cross-sectional view illustrating a protrusion formed on a package.

[0037] Figure 11A It is a cross-sectional view showing the manufacturing process of the transducer.

[0038] Figure 11B It is a cross-sectional view showing the manufacturing process of the transducer.

[0039] Figure 12 It is a top view of the transducer according to the second embodiment.

[0040] Figure 13 yes Figure 12 Cross-sectional view in the direction of the arrow.

[0041] Figure 14A This is a plan view showing an enlarged structure of a dividing slit located at a corner of the inner peripheral surface.

[0042] Figure 14B It is an explanation Figure 14A A diagram showing a modified example of the structure shown.

[0043] Figure 15 It is a top view of the transducer according to the third embodiment.

[0044] Figure 16 It is a top view of the transducer according to the fourth embodiment.

[0045] Figure 17 4 is a top view of a transducer according to a first modification.

[0046] Figure 18 4 is a top view of a transducer according to a second modification.

[0047] Figure 19 4 is a top view of a transducer according to a third modification.

[0048] Figure 20A Yes Figure 19 An enlarged view of the main parts of the transducer is shown.

[0049] Figure 20B It is an explanation Figure 20A A diagram showing a modified example of the structure shown.

[0050] Figure 21 is a cross-sectional view of a transducer according to a fourth modification.

[0051] Figure 22A Yes Figure 21 An enlarged view of the main parts of the transducer is shown.

[0052] Figure 22B It is an explanation Figure 22A A diagram showing a modified example of the structure shown.

[0053] Figure 22C It is an explanation Figure 22A A diagram showing a modified example of the structure shown.

[0054] Figure 23A This is an enlarged cross-sectional view showing a main portion of a transducer according to a fifth modification.

[0055] Figure 23B It is an explanation Figure 23A A diagram showing a modified example of the structure shown.

[0056] Figure 23C It is an explanation Figure 23A A diagram showing a modified example of the structure shown.

[0057] Figure 24 It is a plan view showing an enlarged view of the main part of the transducer according to the sixth modification.

[0058] Figure 25 It is a top view of the transducer according to the fifth embodiment.

[0059] Figure 26 yes Figure 25 Cross-sectional view in the direction of the arrow.

[0060] Figure 27 yes Figure 26 Cross-sectional view in the direction of the arrow.

[0061] Figure 28A It is an explanation Figure 27 A diagram showing a modified example of the structure shown.

[0062] Figure 28B It is an explanation Figure 27 A diagram showing a modified example of the structure shown.

[0063] Figure 29 It is a top view of the transducer according to the sixth embodiment.

[0064] Figure 30 yes Figure 29 Cross-sectional view in the direction of the arrow.

[0065] Figure 31 It is a top view of the transducer according to the seventh embodiment.

[0066] Figure 32 yes Figure 31 Cross-sectional view in the direction of the arrow.

[0067] Figure 33 It will Figure 31 A top view showing an enlarged view of the area surrounded by the dotted line.

[0068] Figure 34 It is a top view of a transducer according to an eighth embodiment.

[0069] Figure 35 yes Figure 34 Cross-sectional view in the direction of the arrow. DETAILED DESCRIPTION

[0070] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are given to the same parts, and description thereof will be omitted.

[0071] (First embodiment)

[0072] Reference Figure 1 and Figure 2 The structure of the transducer 1 of this embodiment is described. The transducer 1 of this embodiment is composed of an acoustic chip 5, a package 60, an external electrode 70 and a contact pad 80 in its main body. Figure 1 The illustrated position of the transducer 1 defines an up and down direction as a reference, but does not define an absolute direction relative to the transducer 1 .

[0073] exist Figure 3 and Figure 4 In FIG, the acoustic chip 5 is composed of a piezoelectric element 10 and a film body 15 .

[0074] The piezoelectric element 10 is composed of a pair of electrodes 11 and 12 and a piezoelectric film 13 sandwiched between the pair of electrodes 11 and 12. The pair of electrodes 11 and 12 and the piezoelectric film 13 have shapes corresponding to the shape of the vibration film 16 described later. Figure 3 and Figure 4 The example shown has a circular shape.

[0075] Each of the electrodes 11 and 12 is formed of a thin film of a conductive metal such as aluminum or copper. The electrode 11 on one side is located on the upper side of the piezoelectric film 13 and is connected to a pair of electrode pads 11a for applying a driving voltage to the electrode 11. The electrode 12 on the other side is located on the lower side of the piezoelectric film 13 and is connected to a pair of electrode pads 12a for applying a driving voltage to the electrode 12. The piezoelectric film 13 is composed of, for example, a lead zirconate titanate (PZT) film. In addition to lead zirconate titanate, the piezoelectric film 13 can also use aluminum nitride (AlZ), zinc oxide (ZnO) or lead titanate (PbTiO3).

[0076] The membrane body 15 is composed of a vibration membrane 16 and a membrane support portion 17. The membrane body 15 is made of, for example, silicon (Si), and the vibration membrane 16 and the membrane support portion 17 are integrally formed by etching the lower surface side of the membrane body 15.

[0077] The vibration film 16 is made of a thin film and is configured to be able to move in the film thickness direction, that is, in the direction of the normal line relative to the vibration film 16 ( Figure 3 The up and down directions on the paper, Figure 4 The diaphragm 16 is displaced in a direction perpendicular to the paper surface. When viewed in a plane perpendicular to the thickness of the diaphragm, the diaphragm 16 has a generally circular shape. Alternatively, the diaphragm 16 may be structured such that a plurality of slits extending radially from the center of the diaphragm 16 are divided into a plurality of regions.

[0078] The membrane support portion 17 is connected to the diaphragm 16 over the entire circumference of the diaphragm 16 to support the diaphragm 16. Below the diaphragm 16, a cylindrical space (cavity) is formed.

[0079] In the acoustic chip 5 thus constructed, a piezoelectric element 10 is provided on the diaphragm 16 of the membrane body 15. Specifically, the diaphragm 16 is stacked in this order with a lower electrode 12, a piezoelectric film 13, and an upper electrode 11. When a driving voltage is applied to each of the pair of electrodes 11 and 12, an electric field is generated between the pair of electrodes 11 and 12. This electric field causes the diaphragm 16 to displace. By repeatedly varying the driving voltage across the pair of electrodes 11 and 12, the diaphragm 16 can be vibrated.

[0080] exist Figure 1 and Figure 2 In FIG. 6 , the package 60 is formed by laminating a plurality of substrates, for example, four substrates 61 to 63. The four substrates 61 to 63 constituting the package 60 are laminated along the film thickness direction of the vibrating membrane 16.

[0081] Specifically, the package 60 is composed of a substrate (upper substrate) 61 constituting the upper surface of the package 60, a substrate (lower substrate) 62 constituting the lower surface of the package 60, and two substrates (middle substrates) 63 stacked between the upper substrate 61 and the lower substrate 62. The outer peripheral shapes of the upper substrate 61, the lower substrate 62, and the middle substrate 63 are substantially the same shape and size as each other. Figure 2 In the example shown, the upper substrate 61, the lower substrate 62, and the intermediate substrate 63 have a quadrilateral shape. However, the outer peripheries of the upper substrate 61, the lower substrate 62, and the intermediate substrate 63 may have different shapes or sizes.

[0082] In the example shown in this figure, upper substrate 61 and lower substrate 62 are each composed of a single substrate, but they may also be composed of two or more substrates. Furthermore, intermediate substrate 63 is composed of two substrates, but it may also be composed of a single substrate, or three or more substrates. Furthermore, the four corners of each substrate 61-63 are rectangular, but they may also be chamfered to a circular arc or tapered shape.

[0083] Each intermediate substrate 63 has a through-hole formed therein that extends through the intermediate substrate 63 in the thickness direction. The through-holes formed in the two intermediate substrates 63 communicate with each other, and these through-holes form an internal space 90 within the package 60. The acoustic chip 5 is housed in the internal space 90 of the package 60 and mounted in the package 60.

[0084] The internal space 90 is divided into an upper space portion 91 located above the vibrating membrane 16 and a lower space portion 92 located below the vibrating membrane 16, with the vibrating membrane 16 as the boundary. In order to connect the upper space portion 91 with the external space located outside the package 60, an upper through-hole 61a is formed on the upper substrate 61, which passes through the upper substrate 61 in the plate thickness direction. The upper through-hole 61a is opposite to the piezoelectric element 10 and the vibrating membrane 16 across the upper space portion 91. In addition, in order to connect the lower space portion 92 with the external space of the package 60, a lower through-hole 62a is formed on the lower substrate 62, which passes through the lower substrate 62 in the plate thickness direction. The lower through-hole 62a is opposite to the vibrating membrane 16 across the lower space portion 92.

[0085] When the driving voltage applied to the pair of electrodes 11 and 12 is repeatedly changed, the vibrating membrane 16 is displaced in the membrane thickness direction. Specifically, the vibrating membrane 16 alternately and repeatedly displaces toward the upper space portion 91 and toward the lower space portion 92, causing the air in the upper space portion 91 to vibrate. The vibration of the air (sound waves) is output to the outside of the package 60 through the upper through-hole 61a. At this time, the lower through-hole 62a ensures the circulation of air in the lower space portion 92, thereby allowing the vibration of the vibrating membrane 16.

[0086] The external electrode 70 is composed of a chip electrode 71, a module electrode 72 and an electrode wiring 73. The chip electrode 71 is connected to the electrode pads 11a and 12a of the acoustic chip 5. The chip electrode 71 is formed on the upper surface of the internal space 90, specifically on the lower surface of the intermediate substrate 63 located on the upper side of the two intermediate substrates 63, in a manner opposite to the electrode pads 11a and 12a of the acoustic chip 5 accommodated in the internal space 90. The module electrode 72 is an electrode for connecting to the electrodes 11 and 12 via the chip electrode 71 and the electrode wiring 73. The module electrode 72 is formed on the upper surface of the package 60, specifically on the upper surface of the upper substrate 61. The electrode wiring 73 connects the chip electrode 71 and the module electrode 72. Through holes that are connected to each other are provided in the upper substrate 61 and the intermediate substrate 63 adjacent to the upper substrate 61, and the electrode wiring 73 is provided in the through holes. In addition, in Figure 1 and Figure 2 Only a portion of the external electrodes is representatively depicted.

[0087] The contact pads 80 are provided in the upper space portion 91 and the lower space portion 92, respectively, and are arranged to face the diaphragm 16. The contact pads 80 function to limit the displacement of the diaphragm 16. Specifically, when the diaphragm 16 displaces toward the upper space portion 91 or the lower space portion 92, the diaphragm 16 or the piezoelectric element 10 on the diaphragm 16 abuts against the contact pads 80, thereby limiting the displacement of the diaphragm 16.

[0088] The distance between the contact surface 80a of the contact pad 80, which contacts the diaphragm 16, and the diaphragm 16 is set based on the displacement of the diaphragm 16 (hereinafter referred to as the "maximum displacement") when the rated voltage is applied to the piezoelectric element 10. Specifically, the contact surface 80a of the contact pad 80 is set so that when a displacement greater than the maximum displacement occurs, the diaphragm 16 or the piezoelectric element 10 contacts the contact surface 80a. This prevents normal displacement of the diaphragm 16 by the piezoelectric element 10 from being obstructed, and only when the piezoelectric film 13 experiences a significant displacement exceeding the maximum displacement due to an impact or the like does the diaphragm 16 contact the contact surface 80a.

[0089] The shape of the abutting surface 80a is formed based on the displacement shape of the vibration membrane 16 when it is displaced. Therefore, when the vibration membrane 16 abuts against the abutting surface 80a, the abutting surface 80a supports the vibration membrane 16 with its surface. For example, the abutting surface 80a of the abutting pad 80 arranged in the upper space portion 91 has a hemispherical shape that is bent upward. Similarly, the abutting surface 80a of the abutting pad 80 arranged in the lower space portion 92 has a hemispherical shape that is bent downward. In addition, a through hole communicating with the upper through hole 61a is formed in the center of the abutting pad 80 provided in the upper space portion 91, and a through hole communicating with the lower through hole 62a is formed in the center of the abutting pad 80 provided in the lower space portion 92.

[0090] As described above, in this embodiment, the transducer 1 includes the contact pad (contact member) 80 that restricts displacement of the vibrating membrane 16 by contacting the piezoelectric element 10 or the vibrating membrane 16 when the vibrating membrane 16 is displaced in the membrane thickness direction.

[0091] According to this structure, the displacement of the diaphragm 16 can be restricted by the contact spacer 80, thereby suppressing excessive displacement of the diaphragm 16 due to shock. This can suppress the occurrence of damage, thereby providing the transducer 1 with resistance to shock.

[0092] In the present embodiment, the package 60 is composed of four substrates 61 to 63 stacked along the film thickness direction of the vibrating membrane 16 .

[0093] According to this structure, by forming each of the substrates 61 to 63 into a predetermined shape and stacking these substrates 61 to 63 , it is possible to easily form the package 60 in a desired shape.

[0094] The transducer 1 of this embodiment is not limited to the above-mentioned structure, and various modifications can be made. Figures 5A to 10 A modification of the transducer 1 of this embodiment will be described. Figures 5A to 10 Although the description of the contact pad 80 is omitted, the contact pad 80 can also be applied to these modified examples.

[0095] (First Modification)

[0096] First, in the above embodiment, the module electrode 72 is provided on the upper surface of the package body 60. However, the module electrode 72 may also be provided on the outer surface of the package body 60. Figure 5A As shown in FIG. 1 , the module electrode 72 is formed on the lower surface side of the lower substrate 62, thereby enabling the module electrode 72 to be provided on the lower surface of the package body 60. Figure 5B As shown, the side surface of the package 60 is formed by arranging the end surfaces of four substrates 61 to 63 in an up-and-down manner. Therefore, the module electrodes 72 are formed on the end surfaces of the four substrates 61 to 63 , thereby enabling the module electrodes 72 to be provided on the side surface of the package 60 .

[0097] Since the package 60 is formed by stacking the four substrates 61 to 63 in this manner, the degree of freedom in the layout of the module electrodes 72 can be increased.

[0098] (Second Modification)

[0099] In the above embodiment, the driving voltage applied to the pair of electrodes 11 and 12 is changed by the electronic components electrically connected to the module electrodes. In this case, the electronic components may also be provided in the package 60.

[0100] exist Figure 6A In the embodiment, the electronic component 200 is mounted on the upper surface of the upper substrate 61 and is provided on the upper surface of the package body 60. Figure 6B In the embodiment, the electronic component 200 is mounted on the lower surface of the lower substrate 62 and is provided on the lower surface of the package body 60. Figure 6C In the example shown, the electronic component 200 is mounted on the upper surface of the lower substrate 62 and is disposed within the internal space 90 .

[0101] Furthermore, when the electronic component 200 is provided in the package 60, power wiring (not shown) for supplying power to the electronic component 200 and signal wiring (not shown) for supplying signals can be formed in the package 60. Furthermore, when the electronic component 200 is mounted on the upper surface or the lower surface of the package 60, it is preferable to form the upper through-hole 61a or the lower through-hole 62a in consideration of the mounting space for the electronic component 200.

[0102] Since the package 60 is formed by stacking the four substrates 61 to 63, the electronic component 200 can be mounted on the package 60. Thus, the transducer 1 provided with the acoustic chip 5 and the electronic component 200 can be provided.

[0103] (Third Modification)

[0104] In the above embodiment, the four substrates 61 to 63 are set to have the same shape and the same size. However, the four substrates 61 to 63 may have different shapes and sizes.

[0105] exist Figure 7A Of the four substrates 61 to 63, the upper substrates 61 and 63 (the upper substrate 61 and the intermediate substrate 63 adjacent to the lower side of the upper substrate 61) are larger in size (area) than the lower substrates 62 and 63 (the lower substrate 62 and the intermediate substrate 63 adjacent to the upper side of the lower substrate 62). Due to this size difference, the peripheral edges of the upper substrates 61 and 63 protrude outward from the peripheral edges of the lower substrates 62 and 63. In other words, the protruding areas of the upper substrates 61 and 63 are formed into a flange shape that surrounds the side surface of the package 60.

[0106] With this structure, when package 60 is mounted on a product housing that accommodates it, the protruding areas of the upper substrates 61 and 63 can be used to secure the package 60 to the product housing. This allows for efficient securing of package 60 to the product housing. In this case, the product housing preferably has a structure that receives the protruding areas of the upper substrates 61 and 63.

[0107] Furthermore, this structure allows the protruding areas of the upper substrates 61 and 63 to extend around the entire periphery of the package 60, thereby sealing the gap between the product housing and the package 60. This allows the airflow around the package 60 to be controlled, stabilizing the acoustic wave output characteristics.

[0108] In addition, since the intermediate substrate 63 adjacent to the lower side of the upper substrate 61 protrudes outward, the lower surface of the intermediate substrate 63 is also exposed to the outside of the package body 60. Figure 7B As shown, the module electrodes 72 may also be formed on the lower surface of the intermediate substrate 63. This allows the chip electrodes 71 and the module electrodes 72 to be directly connected, so that the external electrodes 70 can be formed simply.

[0109] In addition, if Figure 7C As shown in FIG. 1 , the electronic component 200 may also be mounted on the lower surface of the intermediate substrate 63. Figure 7C As shown, the substrate formed to have a larger size can be selected from one or more substrates among the four substrates 61 to 63.

[0110] (Fourth Modification)

[0111] exist Figure 8AIn FIG, the transducer 1 further includes a sealing member 210. The sealing member 210 is disposed in a gap formed between the package 60 and the film body 15. The sealing member 210 is formed in an annular shape and functions to seal the gap between the package 60 and the film body 15.

[0112] This structure can seal the gap between the package 60 and the film 15. This restricts the air flowing through the gap between the package 60 and the film 15, allowing a desired air flow to be achieved. Consequently, the acoustic wave output characteristics can be stabilized.

[0113] (Fifth Modification)

[0114] exist Figure 8B In the embodiment, transducer 1 further includes a sheet member 215. Sheet member 215 is provided on the lower surface of upper substrate 61 so as to close upper through-hole 61a. Furthermore, sheet member 215 is provided on the upper surface of lower substrate 62 so as to close lower through-hole 62a. Sheet member 215 is formed in a sheet shape and made of a material that allows air to pass through. Nonwoven fabric or waterproof, breathable fabric such as GORE-TEX (registered trademark) can be used as sheet member 215.

[0115] According to this structure, since the upper through hole 61a and the lower through hole 62a are closed by the sheet member 215, it is possible to suppress the entry of dust or liquid into the internal space 90. On the other hand, the sheet member 215 is formed of a material that allows air to pass through, so the circulation of air formed by the upper through hole 61a and the lower through hole 62a can be maintained. Figure 8B In the illustrated example, the transducer 1 includes the sealing member 210 , but the sheet member 215 can also be applied to a configuration that does not include the sealing member 210 .

[0116] (Sixth Modification)

[0117] exist Figure 1 and Figure 2 In the illustrated embodiment, the upper through-hole 61a is formed in a linear shape along the thickness direction of the upper substrate 61. However, the upper through-hole 61a may be formed in a shape other than a linear shape.

[0118] exist Figure 8CIn the figure, the upper through hole 61a is composed of a first opening 610, a second opening 611 and a connecting portion 612. The first opening 610 is an opening located on the external space side of the package body 60. The second opening 611 is an opening located on the internal space 90 (upper space portion 91) side. The connecting portion 612 connects the first opening 610 with the second opening 611. When viewed in a plane parallel to the vibrating membrane 16, the position of the first opening 610 is different from the position of the second opening 611. Therefore, it is not possible to go straight from the first opening 610 to the second opening 611, and therefore the connecting portion 612 becomes a shape accompanied by twists and turns. Therefore, the upper through hole 61a as a whole is formed into a non-linear shape.

[0119] According to such a structure, since the upper through hole 61a is not formed in a straight line, it is possible to suppress the entry of dust and the like into the internal space 90. On the other hand, since the upper through hole 61a is connected, the circulation of air can be maintained. Figure 8C In the example shown, the transducer 1 has a sealing member 210, but the structure without the sealing member 210 can also be applied. Figure 8C In addition, not only the upper through hole 61a, but also the lower through hole 62a can be applied. Figure 8C The structure shown.

[0120] (Seventh Modification)

[0121] exist Figure 9A In the embodiment, an inwardly recessed groove 61b is formed on the upper surface of the package 60, that is, on the peripheral edge of the upper substrate 61. The groove 61b is formed along the entire peripheral edge of the upper substrate 61 so as to surround the package 60.

[0122] With this structure, when attaching package 60 to a product housing that houses it, the product housing fits into groove 61b, securing package 60 to the product housing. This allows efficient securing of package 60 to the product housing. In this case, it is preferable to pre-prepare a protrusion structure on the product housing that fits into groove 61b.

[0123] Furthermore, according to this structure, the groove 61b fits into the product case, thereby closing the gap between the product case and the package 60. This allows the airflow around the package 60 to be controlled, stabilizing the output characteristics of the sound wave.

[0124] In addition, Figure 9A In the example shown in FIG, the groove portion 61b is provided on the peripheral edge portion of the upper surface of the package body 60. However, the groove portion 61b may also be provided on the peripheral edge portion of the lower surface of the package body 60. Figure 9BAs shown in FIG. 1 , a groove portion 61 b ​​may be provided around the upper through hole 61 a in the upper surface of the package body 60. Of course, a groove portion 61 b ​​may also be provided around the lower through hole 62 a in the lower surface of the package body 60. Figure 9C As shown, a groove portion 63 a may also be formed on the side surface of the package body 60 .

[0125] In addition, if Figure 10 As shown, instead of groove 61b, a protrusion 64 can be provided on the upper surface of package 60. By utilizing this protrusion 64, package 60 can be attached to a product housing. In this case, the location of protrusion 64 is not limited to the upper surface of package 60; it can also be provided on the lower surface of package 60.

[0126] Below, refer to Figure 11A and Figure 11B The manufacturing method of the transducer 1 of this embodiment is described below, specifically, the method of packaging the acoustic chip 5 with the packaging body 60 is described. The transducer 1 adopts Figure 1 and Figure 2 The structure shown in .

[0127] First, upper substrates 61 and 63 are prepared, each comprising an upper substrate 61 and an intermediate substrate 63 stacked on the lower side of the upper substrate 61. Abutment pads 80 are provided in the upper space 91 formed by the upper substrates 61 and 63. Furthermore, external electrodes 70 are formed on the upper substrates 61 and 63.

[0128] The acoustic chip 5 is mounted on the upper substrates 61 and 63. The acoustic chip 5 is arranged with the electrode pads 11a and 12a facing upward, and the acoustic chip 5 is mounted on the upper substrates 61 and 63.

[0129] Next, lower substrates 62 and 63 are prepared, which include a lower substrate 62 and an intermediate substrate 63 stacked on the lower substrate 62. A contact pad 80 is provided in a lower space 92 formed by the lower substrates 62 and 63.

[0130] Then, the lower substrates 62 and 63 are bonded to the upper substrates 61 and 63 so as to sandwich the acoustic chip 5. Thus, the acoustic chip 5 is packaged in the package 60, and the transducer 1 is completed.

[0131] The substrates 61 to 63 are large-sized substrates, and a plurality of units, each consisting of an acoustic chip 5, an external electrode 70, and a contact pad, are mounted on these substrates 61 to 63. Finally, the acoustic chips 5 are singulated by cutting the substrates 61 to 63, thereby completing the Figure 1 and Figure 2 The transducer 1 is shown.

[0132] Even if an impact is applied to the transducer 1 during singulation, the contact pad 80 can limit the displacement of the diaphragm 16. As a result, it is possible to suppress excessive displacement of the diaphragm 16 due to the impact. This can prevent damage, thereby providing a transducer 1 that is resistant to impact.

[0133] (Second embodiment)

[0134] Reference Figures 12 to 14B The structure of the transducer 1 of this embodiment is described below. The transducer 1 of this embodiment comprises a piezoelectric element 10 and a film 15 in its main body. Figure 13 The illustrated state of the transducer 1 is used as a reference to define the up and down directions, but does not limit the direction in which the transducer 1 is used.

[0135] The piezoelectric element 10 is composed of a pair of electrodes 11 and 12 and a piezoelectric film 13 sandwiched between the pair of electrodes 11 and 12. The pair of electrodes 11 and 12 and the piezoelectric film 13 have shapes corresponding to the shape of the vibration film 16 described later. Figures 12 to 13 The example shown has a quadrilateral shape.

[0136] Each of the pair of electrodes 11 and 12 is formed of a thin film of a conductive metal such as aluminum or copper. One electrode 11 is located on the upper side of the piezoelectric film 13 and is connected to an electrode pad 11a, which is a circuit pattern for applying a driving voltage to the electrode 11. The other electrode 12 is located on the lower side of the piezoelectric film 13 and is connected to an electrode pad 12a, which is a circuit pattern for applying a driving voltage to the electrode 12.

[0137] The piezoelectric film 13 is composed of, for example, a lead zirconate titanate (PZT) film. Aluminum nitride (AlZ), zinc oxide (ZnO), or lead titanate (PbTiO 3 ) can also be used as the piezoelectric film 13 in addition to lead zirconate titanate.

[0138] The membrane body 15 is composed of a vibration membrane 16 and a membrane support portion 17. The membrane body 15 is made of, for example, silicon (Si). The vibration membrane 16 and the membrane support portion 17 are formed integrally by etching the lower surface side of the membrane body 15.

[0139] The diaphragm 16 is made of a thin film and is configured to be able to move in the film thickness direction, that is, in the direction of the normal line relative to the diaphragm 16 ( Figure 12 In the vertical direction of the paper, Figure 13 The diaphragm 16 is displaced in the vertical direction of the paper (in the vertical direction of the paper). When viewed in a plane parallel to the diaphragm 16, the diaphragm 16 has a substantially quadrilateral shape.

[0140] The membrane support portion 17 has a quadrilateral cylindrical inner circumferential surface that forms a cavity (hollow portion) 18. The diaphragm 16 is connected to the inner circumferential surface of the membrane support portion 17 so as to be inscribed within the diaphragm 16, thereby supporting the diaphragm 16 around the membrane support portion 17. The diaphragm 16 is connected to the upper end of the membrane support portion 17, and the upper side of the cavity 18 is sealed by the diaphragm 16.

[0141] The inner peripheral surface is composed of four plane portions 17a and four corner portions 17b that connect adjacent plane portions 17a to each other. Each corner portion 17b is not a shape corresponding to the inner angle of a quadrilateral, but has a chamfered shape. The chamfered shape of the corner portion 17b is formed into a straight line shape when viewed in a plane parallel to the vibrating membrane 16, and the end of the chamfered corner portion 17b is connected to the end of the plane portion 17a. Adjacent plane portions 17a are connected via the chamfered corner portion 17b, thereby connecting the plane portion 17a and the corner portion 17b at an angle (obtuse angle) larger than the angle formed by the adjacent plane portions 17a (the inner angle of the quadrilateral). In addition, when viewed in a plane parallel to the vibrating membrane 16, in addition to being formed by one straight line, the corner portion 17b can also be formed by combining multiple straight lines or by a curve.

[0142] The transducer 1 also has a dividing slit 2. The dividing slit 2 is a cut that penetrates the vibrating body in the thickness direction, in which the piezoelectric element 10 and the vibrating membrane 16 are stacked. The dividing slit 2 divides the vibrating body into a plurality of vibration regions 300.

[0143] The dividing slit 2 includes a main slit portion 2a extending from the center of the vibrating membrane 16 toward the corner 17b. In this embodiment, the inner peripheral surface is quadrilateral, so the dividing slit 2 includes four main slit portions 2a. The four main slit portions 2a divide the vibrating body, which is a laminate of the piezoelectric element 10 and the vibrating membrane 16, into four vibration regions 300.

[0144] Each of the divided diaphragms 16 has a cantilever shape protruding from the diaphragm support portion 17 toward the center of the diaphragm 16. The front end portion of each diaphragm 16 is configured as a free end.

[0145] In addition, if Figure 14A As shown, the dividing slit 2 includes a sub-slit portion 2b. The sub-slit portion 2b extends from the junction between the corner portion 17b and the flat portion 17a, that is, the corner (angle) between the corner portion 17b and the flat portion 17a, to the end of the main slit portion 2a on the corner portion 17b side. Since the corners exist on both sides of the corner portion 17b, two sub-slit portions 2b are provided for each main slit portion 2a.

[0146] For example, when the end of the main slit portion 2a reaches the corner portion 17b, as shown in FIG. Figure 14AAs shown, the auxiliary slit portion 2b is formed in a straight line and connected to the main slit portion 2a in a T-shaped manner. However, the main slit portion 2a does not need to reach the corner portion 17b. In this case, as shown in FIG. Figure 14B As shown, the sub-slit portion 2b is connected to the main slit portion 2a in a Y-shape. Furthermore, the sub-slit portion 2b may be formed in a shape other than a straight line. For example, when viewed in a plane parallel to the diaphragm 16, the corner portion 17b may be formed by combining multiple straight lines. If the corner portion 17b is formed by a curved line, the sub-slit portion 2b may be formed in a shape that follows the corner portion 17b.

[0147] Furthermore, in order to prevent the electrodes 11 and 12 from being divided by the dividing slit 2 , a wiring portion for connecting the electrodes 11 and 12 located in adjacent vibration regions 300 is provided at a position corresponding to the corner portion 17 b .

[0148] In the transducer 1 having such a structure, a piezoelectric element 10 is provided on a vibrating membrane 16 of a membrane body 15. Specifically, a lower electrode 12, a piezoelectric film 13, and an upper electrode 11 are stacked in this order on the vibrating membrane 16. When a driving voltage is applied to each of the pair of electrodes 11 and 12, a potential difference is generated between the pair of electrodes 11 and 12. This potential difference causes the vibrating membrane 16 to displace. Specifically, the front end of the segmented vibrating membrane 16 displaces, tilting upward.

[0149] The diaphragm 16 is alternately displaced upward and downward by repeatedly applying a driving voltage to the pair of electrodes 11 and 12. The vibration of the diaphragm 16 vibrates the air around the diaphragm 16, and the vibration of the air is output as sound waves.

[0150] As described above, in this embodiment, the inner peripheral surface forming the cavity 18 has a quadrilateral shape with four planar portions 17a connected via chamfered corner portions 17b. The dividing slit 2 includes a main slit portion 2a extending from the center of the diaphragm 16 toward the corner portion 17b, and a sub-slit portion 2b extending from the connecting portion (corner) connecting the corner portion 17b and the planar portion 17a to the end of the main slit portion 2a on the corner 17b side.

[0151] According to this structure, because the inner peripheral surface corner 17b is chamfered, the angle at which the flat surface 17a is connected to the corner 17b is increased. This can alleviate the stress concentrated on the corner 17b, thereby improving the strength of the membrane support portion 17.

[0152] When corner portion 17b is chamfered, the connection between the divided diaphragm 16 and the diaphragm support portion 17 is formed into a zigzag shape consisting of a straight line along one flat surface portion 17a and a straight line along corner portion 17b. Because there is a zigzag point (corner) between flat surface portion 17a and corner portion 17b, if the divided diaphragm 16 is displaced, stress will concentrate at the zigzag point, potentially causing cracking.

[0153] Therefore, in this embodiment, the secondary slit portion 2b extends from the end of the main slit portion 2a to the corner. This ensures that the connection between the divided diaphragm 16 and the membrane support portion 17 is formed solely by the linear region corresponding to the flat surface portion 17a. Even if the diaphragm 16 is displaced, stress concentration on specific locations can be suppressed. As a result, the strength of the diaphragm 16 and the membrane support portion 17 can be increased, thereby preventing damage.

[0154] In the above embodiment, the inner peripheral surface forming the cavity 18 is configured as a quadrilateral. However, the inner peripheral surface may be configured as a polygon, for example, a hexagon, an octagon, a pentagon, or a heptagon.

[0155] (Third embodiment)

[0156] Reference Figure 15 The transducer 1 of this embodiment will be described. The transducer 1 of this embodiment differs from the transducer 1 of the second embodiment in the structure of the piezoelectric element 10. The description of the contents overlapping with the second embodiment will be omitted, and the following description will focus on the differences.

[0157] The piezoelectric element 10 includes a piezoelectric slit 14 extending through the piezoelectric element 10 in the thickness direction. Each piezoelectric slit 14 is provided for each vibration region 300. Specifically, the piezoelectric slit 14 extends perpendicularly from the planar portion 17a to the dividing slit 2 (main slit portion 2a). Each vibration region 300 is divided into a plurality of small regions by the piezoelectric slit 14. Furthermore, each small region is discontinuous in a direction parallel to the planar portion 17a (lateral direction).

[0158] The displacement of the diaphragm 16, which is divided by the dividing slit 2, increases from the flat surface 17a toward the front end. Ideally, the displacement of the diaphragm 16 is the same at all positions when viewed in the lateral direction. However, as the diaphragm 16 repeatedly vibrates, it may warp in the lateral direction, causing deformation of the diaphragm 16.

[0159] In this embodiment, the piezoelectric element 10 is divided in the lateral direction by the piezoelectric slits 14, thereby suppressing lateral warping of the diaphragm 16. This suppresses deformation of the diaphragm 16 and allows the diaphragm 16 to vibrate appropriately.

[0160] Furthermore, although four piezoelectric gaps 14 are provided for one vibration region 300 , one or more piezoelectric gaps 14 may be provided. Furthermore, the number of piezoelectric gaps 14 may be different for each vibration region 300 .

[0161] (Fourth embodiment)

[0162] Reference Figure 16 , the transducer 1 of this embodiment will be described. The transducer 1 of this embodiment differs from the transducer 1 of the second embodiment in the connection configuration between the electrodes 11 and 12 and the electrode pads 11a and 12a. The connection configuration between the electrode 11 and the electrode pad 11a will be described below; the connection configuration between the electrode 12 and the electrode pad 12a is also the same. The description of the content that overlaps with the second embodiment will be omitted, and the description will focus on the differences.

[0163] Electrode pads 11a are provided for each vibration region 300 divided by the dividing slits 2. Specifically, four electrode pads 11a are provided, each connected to the upper electrode 11. One electrode pad 11a is provided for each vibration region 300, and each electrode pad 11a is connected to the electrode 11 of the corresponding vibration region 300.

[0164] When external forces act and membrane 15 deforms, cracks may form at the ends of dividing slit 2, and these cracks may spread to electrode 11. For example, if cracks form at opposing corners 17b, electrode 11 may be split into two, blocking the current path and rendering transducer 1 inoperable.

[0165] In this regard, according to this embodiment, an electrode pad 11a is provided for each of the four divided regions 300. Therefore, the electrode 11 can be connected to the electrode pad 11a in each of the four vibration regions 300. Even if the electrode 11 is divided into two, the driving voltage can continue to be applied to each of the divided regions. This allows the transducer 1 to continue operating.

[0166] Furthermore, in this embodiment, one electrode pad 11 a is provided for each vibration region 300. However, a pair of electrode pads 11 a may be provided for each vibration region 300. Thus, the electrode 11 is connected to the pair of electrode pads 11 a in each vibration region 300. Therefore, even if the electrode 11 is separated by cracks, the diaphragm 16 can be vibrated in each independent vibration region 300.

[0167] Hereinafter, modifications applicable to the second to fourth embodiments will be described. The modifications described below are applicable to any of the second to fourth embodiments unless otherwise specified.

[0168] (First Modification)

[0169] Reference Figure 17 , a transducer 1 according to a first modification is described. In this first modification, the piezoelectric element 10 has an opening 20 penetrating the piezoelectric element 10 in the thickness direction in a central region corresponding to the center of the vibrating membrane 16. Figure 17 In FIG, the opening 20 is formed into a quadrilateral shape similar to the vibration membrane 16 . That is, the piezoelectric element 10 is not provided in the central region of the vibration membrane 16 , but is provided only in the outer region outside the opening 20 .

[0170] The warping of the free ends of the divided diaphragm 16 creates a gap in the thickness direction of the diaphragm 16. Air moves through this gap, causing air leakage when the air is vibrated. The structure of the first variant suppresses the warping of the free ends of the diaphragm 16. This suppresses the movement of air caused by the warping of the diaphragm 16, allowing the air to be vibrated efficiently.

[0171] (Second Modification)

[0172] Reference Figure 18 , explaining the transducer 1 of the second modified example. In this second modified example, the dividing slit 2 further includes a third slit portion 2d that divides the vibrating body having the vibrating membrane 16 and the piezoelectric element 10 stacked thereon. The third slit portion 2d extends from the center of the vibrating membrane 16 toward the center of the flat portion 17a. The third slit portion 2d is not provided on all of the four flat portions 17a. Figure 18 In the example shown, only two planar portions 17 a facing each other are provided.

[0173] In this manner, the vibrating body, in which the vibrating membrane 16 and the piezoelectric element 10 are stacked, is divided into six vibration regions by the main slits 2a and the third slits 2d. Specifically, the six vibration regions include a first vibration region 301 located between the pair of main slits 2a, and a second vibration region 302 located between the main slits 2a and the third slits 2d. The second vibration region 302 is divided into a shape different from that of the first vibration region 301, specifically, into a triangular shape with a smaller angle toward the front end than the first vibration region 301.

[0174] According to this structure, since the first vibration region 301 and the second vibration region 302 have different shapes, the resonance frequencies of the vibration regions 301 and 302 are shifted. This can achieve a wider output characteristic than when all vibration regions have the same shape.

[0175] In the present embodiment, the plurality of vibration regions are configured with two shapes, but may be configured with three or more shapes. In addition, all of the plurality of vibration regions may have different shapes.

[0176] (Third Modification)

[0177] Reference Figure 19 、 Figure 20A and Figure 20B , describing a transducer 1 according to a third modified example. In this third modified example, the transducer 1 includes a film protective layer 30 stacked on the piezoelectric element 10. The film protective layer 30 serves to protect the connection between the vibrating membrane 16 and the inner peripheral surface. The film protective layer 30 is a thin film formed of a soft elastic material, such as a resin. The film protective layer 30 is provided with a predetermined width along the inner peripheral surface (the flat surface 17a and the corner portion 17b) of the membrane support portion 17 forming the cavity 18, and may also be provided so as to cover the entire surface of the piezoelectric element 10.

[0178] When a large displacement is applied to the diaphragm 16 or an impact is applied to the membrane 15, cracks may occur at the connection between the diaphragm 16 and the inner peripheral surface. However, according to this embodiment, the membrane protection layer 30 covers the connection portion, thereby protecting the membrane 15 from damage.

[0179] Furthermore, the membrane protection layer 30 is a structure that includes the connection portion between the vibration membrane 16 and the inner peripheral surface, so it is sufficient to provide protection at least in the connection portion. Therefore, the membrane protection layer 30 can be formed into a shape in which a portion of the membrane protection layer 30 is removed as it moves inward from the inner peripheral surface. For example, Figure 20B In the example shown, the film protective layer 30 has triangular slits continuously provided in the circumferential direction.

[0180] (Fourth Modification)

[0181] Reference Figure 21 、 Figures 22A to 22C The transducer 1 of the fourth modification is described. In the fourth modification, the transducer 1 has a covering layer 40 stacked on the piezoelectric element 10. The covering layer 40 is provided, for example, to cover the entire area of ​​the piezoelectric element 10, but may also exist in a range that covers at least the dividing gap 2. The covering layer 40 is made of a soft material that expands and contracts according to the displacement of the vibrating membrane 16, such as a thin film formed of resin. Figure 22A In the embodiment, the cover layer 40 located on the dividing slit 2 is provided in a planar manner so as to close the upper portion of the dividing slit 2 .

[0182] According to this structure, since the dividing slit 2 is covered by the covering layer 40, the movement of air from one side of the vibrating membrane 16 to the opposite side can be suppressed. As a result, the movement of air through the dividing slit 2 can be suppressed, so the air can be vibrated efficiently. In addition, since the front end portions of the cantilever shape are connected to each other, the sudden displacement of the front end portions can be suppressed when a strong external impact is input. This can prevent damage such as breakage of the vibrating membrane 16.

[0183] Here, if Figure 22B As shown, the covering layer 40 can be provided along the longitudinal grooves of the dividing slit 2. In the case of this structure, when the vibration membrane 16 is displaced, the covering layer 40 is peeled off from the longitudinal grooves of the dividing slit 2, thereby allowing the displacement of the vibration membrane 16. The covering layer 40 is formed by stacking the covering layer 40 in a thin film on the basis of the vibration body in which the vibration membrane 16 and the piezoelectric element 10 are stacked to form the dividing slit 2. In addition, as Figure 22B As shown, the front end side of the vibration region 300 may be chamfered so that the thickness decreases toward the center of the vibration membrane 16 .

[0184] (Fifth Modification)

[0185] Reference Figures 23A to 23C A transducer 1 according to a fifth modified example will be described. Figure 23A , the front end sides of a pair of vibration regions 300 facing each other are shown. In this fifth modification, the front end of each of the four vibration regions 300 is chamfered so that the thickness decreases as it goes toward the center of the vibration membrane 16. Figure 23A In the illustrated example, the upper surface side of the front end portion of the vibration region 300 is chamfered.

[0186] When the pair of opposing vibration regions 300 displace, the tips of the vibration regions 300 may collide with each other. Therefore, by chamfering the tips of the vibration regions 300, a gap is created for the tips to escape, thereby suppressing such collisions. This also helps prevent damage to the diaphragm 16.

[0187] Furthermore, the chamfered portion is not limited to the upper surface side of the front end portion of the vibration region 300, but may be both the upper surface side and the lower surface side of the front end portion (see Figure 23B ). Alternatively, the chamfering method of the front end portion may be a method of continuously chamfering from the upper surface to the lower surface (see Figure 23C ).

[0188] (Sixth Modification)

[0189] Reference Figure 24 A sixth modified example of the transducer 1 will be described. The sixth modified example is characterized in the shape of the tip of the vibration region 300 .

[0190] In the sixth modification, a circular protrusion 300a extending to the center of the diaphragm 16 is provided at the tip of any one of the four vibration regions 300. Meanwhile, arc-shaped notches 300b are formed at the tip of the remaining four vibration regions 300 to surround the protrusion 300a.

[0191] Because the notch 300b is provided to match the shape of the protrusion 300a, collision between the front ends of the vibration region 300 can be suppressed. This prevents damage to the diaphragm 16. Furthermore, the protrusion 300a seals the gap in the center of the diaphragm 16. As a result, the movement of air from one side of the diaphragm 16 to the other side can be suppressed, allowing the diaphragm 16 to effectively vibrate the air.

[0192] The first to sixth modified examples have been described above. However, the first to sixth modified examples can also be utilized by combining the technical features described in the respective modified examples.

[0193] (Fifth embodiment)

[0194] Below, refer to Figures 25 to 27 The transducer 1 of this embodiment is described. The transducer 1 of this embodiment differs from the transducer 1 of the second embodiment in the structure of the membrane support portion 17. The description of the contents overlapping with the second embodiment is omitted, and the following description focuses on the differences.

[0195] In this embodiment, the corners 17b forming the cavities 18 are shaped to correspond to the interior angles of a quadrilateral. That is, adjacent planar portions 17a are connected at 90° angles via the corners 17b. In this membrane support portion 17, three small cavities 17c, or hollow portions, extending in the thickness direction of the diaphragm 16 are provided around the corners 17b. Each small cavity 17c is independent and located at a position not connected to the cavity 18.

[0196] Small cavity 17c extends from the lower surface to the upper surface of membrane support portion 17 and is formed to a height (depth) not penetrating membrane support portion 17. When viewed in a plane parallel to diaphragm 16, small cavity 17c has a circular or elliptical shape.

[0197] When the inner circumference is polygonal, stress generated in the membrane body 15 is concentrated at the corners 17b. Therefore, in this embodiment, small cavities 17c are provided around the corners 17b to alleviate the stress concentrated at the corners 17b. Furthermore, even if cracks develop at the corners 17b, the presence of the small cavities 17c formed by the curved surface around the corners 17b can prevent the cracks from developing. This prevents significant damage to the membrane support portion 17.

[0198] In addition, if Figure 28A and Figure 28B As shown, it can also be formed in a manner that the small cavity 17c is connected to the cavity 18. Figure 28A In the example shown, the small cavity 17c is directly connected to the cavity 18. Figure 28B In the example shown, the small cavity 17 c communicates with the cavity 18 via a slit-shaped communicating portion 17 c 1 .

[0199] (Sixth embodiment)

[0200] Below, refer to Figure 29 and Figure 30 , explaining the transducer 1 of this embodiment. The difference between the transducer 1 of this embodiment and the transducer 1 of the second embodiment lies in the structure of the membrane support portion 17. The description of the contents repeated in the second embodiment is omitted, and the following description focuses on the differences. Figure 29 In the figure, a part of the electrode pads 11a and 12a is omitted.

[0201] In this embodiment, the membrane support portion 17 has an inner circumferential surface that forms a cavity 18. This inner circumferential surface is formed of a single curved surface portion 17d and has a circular shape. Furthermore, a groove portion 17e having a depth that does not penetrate the membrane support portion 17 is formed on the upper surface side. The groove portion 17e is located outside the curved surface portion 17d and is formed so as to surround the curved surface portion 17d.

[0202] Furthermore, in order to protect the wiring connecting the electrodes 11 and 12 and the electrode pads 11a and 12a, the grooves 17e are not formed in the wiring area. Instead, the grooves 17e are provided on the outer periphery of the wiring area, and the grooves 17e are doubled.

[0203] With this structure, a groove 17e is formed on the upper surface of the membrane support portion 17, surrounding the diaphragm 16. This allows the region of the membrane support portion 17 located inward of the groove 17e to bend inward. As a result, the region located inward of the groove 17e can be displaced inward in response to the displacement of the diaphragm 16, thereby increasing the amount of deflection of the diaphragm 16. This allows the diaphragm 16 to be displaced more significantly, effectively vibrating the air.

[0204] (Seventh embodiment)

[0205] the following, Figures 31 to 33 The transducer 1 of this embodiment is described below. The transducer 1 of this embodiment differs from the transducer 1 of the second embodiment in the structure of the dividing slit 2. The description of the contents overlapping with the second embodiment is omitted, and the following description focuses on the differences.

[0206] In this embodiment, the membrane support portion 17 has an inner peripheral surface that forms a cavity 18. The inner peripheral surface is formed by a single curved surface portion 17d and has a circular shape. Furthermore, the transducer 1 has a dividing slit 2 that divides the vibrating body formed by stacking the piezoelectric element 10 and the vibrating membrane 16 into a plurality of vibration regions 300.

[0207] The dividing gap 2 includes four main gaps 2a extending from the center of the vibrating membrane 16 to the curved surface portion 17d. The four main gaps 2a are distributed in a radial shape, thereby dividing the vibrating body in which the piezoelectric element 10 and the vibrating membrane 16 are stacked into four vibration regions 300. Figure 33 As shown, the end portion of the main slit portion 2a on the curved surface portion 17d side is formed in a curved shape.

[0208] In addition, if Figure 33 As shown, a gap protection layer 50 is provided at the end of the main gap portion 2a on the curved surface portion 17d side. The gap protection layer 50 is large enough to surround the end of the main gap portion 2a. The gap protection layer 50 is a thin film formed of a soft material. Alternatively, the gap protection layer 50 can be formed of the same material as any of the electrodes 11, 12, and the piezoelectric film 13. In this case, there is no need to prepare a unique material for the gap protection layer 50, thereby reducing the complexity of the manufacturing process of the transducer 1.

[0209] If the ends of the main slit 2a are formed at right angles, there is a concern that stress may concentrate at the corners. However, according to this embodiment, the ends of the main slit 2a are formed into a curved shape. This can prevent stress from concentrating at specific locations at the ends of the main slit 2a. This can also prevent cracks from occurring at the ends of the main slit 2a.

[0210] Furthermore, the end of the main slit portion 2a may have a shape other than a curved shape. For example, it may have a polygonal shape formed by combining three or more straight lines. Furthermore, it may have a shape that combines a curved shape with a polygonal shape, such as a combination of two or more curved lines and one or more straight lines, or a combination of one or more curved lines and two or more straight lines.

[0211] In addition, in this embodiment, a gap protection layer 50 is disposed at the end of the main gap portion 2a. The end of the main gap portion 2a is protected by the gap protection layer 50. This can suppress the occurrence of cracks at the end of the main gap portion 2a.

[0212] Furthermore, in the method shown in this embodiment, the inner peripheral surface forming the cavity 18 is formed into a circular shape, but the shape of the inner peripheral surface may also be a polygonal shape.

[0213] (Eighth Embodiment)

[0214] Below, refer to Figures 34 to 35 The transducer 1 of this embodiment is described. The difference between the transducer 1 of this embodiment and the transducer 1 of the second embodiment lies in the operation structure of the vibrating membrane 16. The description of the contents repeated in this embodiment is omitted, and the following description focuses on the differences. Figure 34 In FIG. 1 , a part of the electrode pads 11 a and 12 a is omitted.

[0215] In this embodiment, the membrane body 15 is composed of a cantilever-type vibrating membrane 16 and a membrane support portion 17. The vibrating membrane 16 has a roughly quadrilateral shape when viewed in a plane parallel to the vibrating membrane 16. The membrane support portion 17 surrounds the vibrating membrane 16 and is connected to one side of the vibrating membrane 16. A gap 19 is set between the remaining three sides of the vibrating membrane 16 and the membrane support portion 17. In other words, the vibrating membrane 16 is supported in a cantilever shape.

[0216] The piezoelectric element 10 is not provided on the free end side of the vibrating membrane 16, but is arranged on the base end side connected to the membrane support portion 17. When a driving voltage is applied to the pair of electrodes 11 and 12, a potential difference is generated between the pair of electrodes 11 and 12. Due to this potential difference, the free end side of the vibrating membrane 16 is displaced in the membrane thickness direction. By repeatedly applying a driving voltage to the pair of electrodes 11 and 12, the vibrating membrane 16 alternately and repeatedly displaces upward and downward. The vibration of the vibrating membrane 16 causes the air around the vibrating membrane 16 to vibrate, and the vibration of the air is output as sound waves.

[0217] As one of the features of this embodiment, shielding members 16b are provided on three sides of the vibrating membrane 16, which is separated from the membrane support portion 17 by a gap 19. The shielding members 16b are provided on the surface opposite to the piezoelectric element 10 and extend toward the cavity 18. The shielding members 16b provided on the side located on the free end side are formed continuously along the side. On the other hand, the shielding members 16b provided on the two sides connecting the free end side and the base end side are provided intermittently at predetermined intervals (gaps).

[0218] Furthermore, a space portion 17f is formed on the surface of the membrane support portion 17 that faces the free end side of the vibration membrane 16. The space portion 17f is formed so that the upper portion of the membrane support portion 17 remains.

[0219] The warping of the free end of the diaphragm 16 creates a gap in the thickness direction of the diaphragm 16. Air moves through this gap, increasing air leakage during air vibration. However, according to this embodiment, a shielding member 16b is provided on the lower surface of the diaphragm 16. This shielding member 16b suppresses the formation of the gap, thereby preventing air leakage.

[0220] Furthermore, shielding members 16b are intermittently formed on the raised sides of the diaphragm 16. Thus, the shielding members 16b do not hinder the displacement of the diaphragm 16. As a result, the diaphragm 16 can be allowed to vibrate.

[0221] Furthermore, by providing space 17f in membrane support 17, interference between shield 16b provided on the free end and membrane support 17 can be prevented. This allows for free displacement of diaphragm 16. Furthermore, space 17f is formed so as to leave the upper portion of membrane support 17 free, thereby preventing the gap 19 between diaphragm 16 and membrane support 17 from increasing in size. This also suppresses the flow of air through gap 19.

[0222] The fifth to eighth embodiments have been described above, and the fifth to eighth embodiments can also utilize the technical features shown in each embodiment in combination with each other. In addition, the fifth to eighth embodiments can utilize the technical features shown in the first to fourth embodiments and the modified examples of each embodiment in combination with each other.

[0223] The embodiments of the present invention are described above, and the description and drawings constituting a part of the present invention should not be understood as limiting the content of the present invention. According to the present invention, those skilled in the art will understand alternative embodiments, examples, and application technologies.

[0224] For example, the transducer can be used not only for transmitting sound waves but also for receiving sound waves. In addition, the transducer is not limited to being used for sound waves, but can also be used for transmitting or receiving ultrasonic waves.

[0225] Description of Reference Signs

[0226] 1 transducer

[0227] 2 split gaps

[0228] 2a Main gap

[0229] 2b auxiliary gap

[0230] 5 audio chip

[0231] 10 piezoelectric elements

[0232] 11, 12 electrodes

[0233] 13 Piezoelectric film

[0234] 14 Piezoelectric gap

[0235] 15 membrane

[0236] 16 vibration membranes

[0237] 16b shielding piece

[0238] 17 membrane support part

[0239] 17a plane part

[0240] 17b Corner

[0241] 17c small cavity

[0242] 17d curved face

[0243] 17e groove

[0244] 18 cavities

[0245] 19 gap

[0246] 20 opening

[0247] 30 membrane protective layer

[0248] 40 covering layers

[0249] 50 gap protection layer

[0250] 60 package

[0251] 61 upper substrate

[0252] 62 lower substrate

[0253] 63 intermediate substrate

[0254] 70 external electrodes

[0255] 71 chip electrodes

[0256] 72 module electrodes

[0257] 73 electrode wiring

[0258] 80 abutment pad

[0259] 80a contact surface

[0260] 90 interior space

[0261] 91 Upper Space Department

[0262] 92 Lower Space Department

[0263] 300 vibration zones

Claims

1. A transducer, characterized in that: include: a membrane support portion having a cylindrical inner peripheral surface forming a hollow portion; a vibrating membrane connected to the inner peripheral surface over the entire circumference thereof and capable of displacement in a membrane thickness direction; a piezoelectric element stacked on the vibration film and having a pair of electrodes and a piezoelectric film sandwiched between the pair of electrodes; and a dividing slit which penetrates the vibrating body formed by laminating the vibrating film and the piezoelectric element in the thickness direction and divides the vibrating body into a plurality of vibration regions; The inner peripheral surface has a polygonal shape in which a plurality of planar portions are connected via chamfered corner portions. The dividing gap has: a main slit portion extending from the center of the diaphragm toward the corner; and A sub-slit portion extends from a connecting portion connecting the corner portion and the flat portion to an end portion of the main slit portion on the corner portion side.

2. The transducer according to claim 1, wherein: The piezoelectric element has a piezoelectric slit that penetrates the piezoelectric element in a thickness direction and extends from the planar portion to the dividing slit along a direction perpendicular to the planar portion.

3. The transducer according to claim 1 or 2, characterized in that: Each of the pair of electrodes is connected to a circuit pattern for applying a driving voltage to the electrode for each of the plurality of vibration regions.

4. The transducer according to claim 1 or 2, characterized in that: The piezoelectric element has an opening portion penetrating the piezoelectric element in a thickness direction in a region corresponding to a center of the vibration membrane.

5. The transducer according to claim 1 or 2, characterized in that: The plurality of vibration regions include: a first vibration region; and The second vibration region is divided into a shape different from that of the first vibration region.

6. The transducer according to claim 1 or 2, characterized in that: A film protection layer is further provided on the piezoelectric element along the inner peripheral surface to protect a connection portion between the vibration film and the inner peripheral surface.

7. The transducer according to claim 1 or 2, characterized in that: A cover layer is further provided on the piezoelectric element so as to cover the dividing slits and expands and contracts in response to the displacement of the vibration membrane.

8. The transducer according to claim 1 or 2, characterized in that: Each of the plurality of vibration regions is chamfered so that a thickness of a front end portion located on a center side of the vibration membrane decreases toward the center of the vibration membrane.

9. The transducer according to claim 1 or 2, characterized in that: A circular protrusion extending to the center of the vibration membrane is provided at the front end of any one of the plurality of vibration regions. A notch portion formed in an arc shape so as to surround the protrusion is provided at a front end portion of each of the plurality of vibration regions except the vibration region provided with the protrusion.

Images