Audio devices

Abstract

To provide a coil component that suppresses the reduction in a self-resonant frequency.SOLUTION: An acoustic device 1 includes a piezoelectric transducer 2, a vibration panel 3 that is vibrated by the piezoelectric transducer 2, an enclosure 4 that defines an interior space 80 together with the vibration panel 3, and a partition 6 that is arranged opposing the vibration panel 3 and divides the interior space 80 into a plurality of spaces (a first space 81 and a second space 82). The partition 6 is formed with at least one through-hole 67 that connects the plurality of spaces (the first space 81 and the second space 82) to each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This disclosure relates to an acoustic device. [Background technology]

[0002] Acoustic devices comprising a piezoelectric vibrator and a vibrating panel that vibrates by the piezoelectric vibrator are known (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 04-70100 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] One aspect of the present invention aims to provide an acoustic device capable of adjusting the sound pressure of sound generated from a vibrating panel. [Means for solving the problem]

[0005] An acoustic device according to one aspect of the present invention comprises a piezoelectric vibrator, a vibrating panel that vibrates by the piezoelectric vibrator, a housing that defines an internal space together with the vibrating panel, and a partition that is positioned opposite the vibrating panel and divides the internal space into a plurality of spaces. The partition has at least one through-hole that connects the plurality of spaces.

[0006] In the acoustic device according to the above embodiment, the internal space is divided into multiple spaces by a partition. The multiple divided spaces are connected by at least one through-hole formed in the partition. Therefore, sound generated from the vibrating panel enters the spaces divided by the partition through at least one through-hole. The at least one through-hole through which sound enters and the space connected to the through-hole constitute a Helmholtz resonator, which can increase or decrease sound pressure. Thus, the acoustic device according to this embodiment can adjust the sound pressure of the sound generated from the vibrating panel.

[0007] In one of the above embodiments, the piezoelectric vibrator may be placed on a vibrating panel. The partition has a region in which at least one through hole is formed, and this region may face the piezoelectric vibrator. When a region with at least one through-hole faces a piezoelectric vibrator, sound generated from the vibrating panel can easily enter the Helmholtz resonator, which is formed by the at least one through-hole in that region and the space connected to the through-hole. Therefore, the sound pressure can be efficiently adjusted by the Helmholtz resonator.

[0008] In one of the above embodiments, the partition may have a plurality of through holes, each containing at least one through hole. When multiple through-holes are formed in a partition, it becomes possible to adjust the shape and position of each of the through-holes. This can facilitate the design of acoustic devices to achieve a desired Helmholtz resonance frequency.

[0009] In one of the above embodiments, the vibration panel may have an inner main surface facing the internal space. The piezoelectric vibrator may be arranged on the inner main surface. When the piezoelectric vibrator is positioned on the inner main surface, the piezoelectric vibrator is located in the internal space. Therefore, the piezoelectric vibrator is protected from external shocks, such as those from the acoustic device, by the vibration panel and housing.

[0010] In one of the above embodiments, the partition may divide the internal space into two spaces. The housing may have a frame that defines one of the two spaces together with the vibration panel, and a base that defines the other of the two spaces. The base may include a bottom wall and side walls that extend in a direction intersecting the bottom wall. The partition may have a flat plate shape and may be placed on the end face of the side wall. The frame may be placed on the partition so as to sandwich the partition between its end face and the frame. The fact that the frame and base, which are positioned to sandwich the partition, are separate components makes it easier to manufacture the acoustic device.

[0011] In one of the above embodiments, the frame may have through holes through which wiring electrically connected to the piezoelectric vibrator is inserted. When through-holes are formed in the frame, even if the piezoelectric vibrator to which the wiring is connected is located in the internal space, the wiring is positioned from the internal space to the external space of the acoustic device through the through-holes. Therefore, the degree of freedom in positioning the piezoelectric vibrator and wiring is improved. [Effects of the Invention]

[0012] One aspect of the present invention provides an acoustic device capable of adjusting the sound pressure of sound generated from a vibrating panel. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a perspective view showing an acoustic device according to this embodiment. [Figure 2] Figure 2 is an exploded perspective view showing the acoustic device according to this embodiment. [Figure 3] Figure 3 shows the cross-sectional configuration of the acoustic device according to this embodiment. [Figure 4] Figure 4 is a plan view showing the acoustic device according to this embodiment. [Figure 5] Figure 5 is a magnified view showing the gap between the vibration panel and the frame. [Figure 6]FIG. 6 is a diagram showing a cross-sectional configuration of an acoustic device according to a first modification. [Figure 7] FIG. 7 is a diagram showing a cross-sectional configuration of an acoustic device according to a second modification. MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant descriptions are omitted.

[0015] Referring to FIGS. 1 to 4, the configuration of the acoustic device 1 according to the present embodiment will be described. FIG. 1 is a perspective view showing the acoustic device 1 according to the present embodiment. FIG. 2 is an exploded perspective view showing the acoustic device 1 according to the present embodiment. FIG. 3 is a diagram showing a cross-sectional configuration of the acoustic device 1 according to the present embodiment. The cross-section shown in FIG. 3 is a cross-section when the acoustic device 1 according to the present embodiment is cut along line III-III shown in FIG. 1. FIG. 4 is a plan view showing the acoustic device 1 according to the present embodiment. FIG. 4 is a view when the acoustic device 1 is viewed from the piezoelectric vibrator 2 side, and a plurality of through holes 67 located inside the acoustic device 1 are shown by broken lines. Actually, the plurality of through holes 67 cannot be visually recognized from the outside of the acoustic device 1. The acoustic device 1 includes a piezoelectric vibrator 2, a vibration panel 3, a housing 4 that defines an internal space 80 together with the vibration panel 3, and a partition 6 that divides the internal space 80 into a plurality of spaces. The piezoelectric vibrator 2 is disposed on the vibration panel 3.

[0016] The acoustic device 1 functions, for example, as a speaker. The acoustic device 1 has a roughly rectangular parallelepiped shape. In this embodiment, the "rectangular parallelepiped shape" includes a rectangular parallelepiped shape with chamfered corners and edges, and a rectangular parallelepiped shape with rounded corners and edges. Hereinafter, the longitudinal direction of the acoustic device 1 will be referred to as direction X, the short direction of the acoustic device 1 as direction Y, and the thickness direction of the acoustic device 1 as direction Z. In this embodiment, directions X, Y, and Z are orthogonal to each other. In direction Z, the direction from the partition 6 toward the piezoelectric vibrator 2 will be referred to as the upward direction, and the opposite direction will be referred to as the downward direction. As an example, the width of the acoustic device 1 in direction X may be 100 mm, the width in direction Y may be 50 mm, and the thickness in direction Z may be 40 mm.

[0017] The piezoelectric vibrator 2 vibrates when a voltage is applied. In this embodiment, the piezoelectric vibrator 2 is a multilayer piezoelectric element. The piezoelectric vibrator 2 may also be a bimorph piezoelectric element. The piezoelectric vibrator 2 has a substantially rectangular parallelepiped shape. As shown in Figure 3, the piezoelectric vibrator 2 has a pair of main surfaces 21 and 22 that face each other in direction Z. Main surface 21 is located above main surface 22 in direction Z. The piezoelectric vibrator 2 is arranged on the outer main surface 31 of the vibration panel 3, which will be described later. In this embodiment, when it is stated that one element is arranged on another element, that element may be directly arranged on the other element or indirectly arranged on the other element. When an element is directly arranged on another element, it means that there is no intervening element between the element and the other element. When an element is indirectly arranged on another element, it means that there is an intervening element between the element and the other element. The piezoelectric vibrator 2 is bonded to the vibration panel 3 via an adhesive layer.

[0018] Each main surface 21, 22 has a rectangular shape when viewed from direction Z. In this embodiment, "rectangular shape" includes rectangular shapes with chamfered corners and rectangular shapes with rounded corners. Each main surface 21, 22 has a pair of long sides and a pair of short sides. The piezoelectric vibrator 2 is arranged on the vibration panel 3 such that the long sides of each main surface 21, 22 are aligned with direction X and the short sides of each main surface 21, 22 are aligned with direction Y. The arrangement direction of the piezoelectric vibrator 2 is not limited. For example, the piezoelectric vibrator 2 may be arranged on the vibration panel 3 such that the long sides of each main surface 21, 22 are aligned with direction Y and the short sides of each main surface 21, 22 are aligned with direction X.

[0019] The piezoelectric vibrator 2 includes a plurality of piezoelectric layers (not shown) stacked in the Z direction, and a plurality of internal electrodes (not shown) located between each piezoelectric layer. In this embodiment, the surface of the uppermost piezoelectric layer in the Z direction constitutes the main surface 21, and the surface of the lowermost piezoelectric layer constitutes the main surface 22. The piezoelectric vibrator 2 has external electrodes (not shown) electrically connected to the plurality of internal electrodes on the main surface 21. A piezoelectric vibrator comprising a plurality of piezoelectric layers, a plurality of internal electrodes, and a plurality of external electrodes is well known to those skilled in the art, and a detailed description of the configuration of such a piezoelectric vibrator is omitted.

[0020] Each piezoelectric layer is made of a piezoelectric material. In this embodiment, each piezoelectric layer is made of a piezoelectric ceramic material. Examples of piezoelectric ceramic materials include PZT[Pb(Zr,Ti)O3], PT(PbTiO3), PLZT[(Pb,La)(Zr,Ti)O3], or barium titanate (BaTiO3). Each piezoelectric layer is made of, for example, a sintered body of a ceramic green sheet containing the piezoelectric ceramic material described above. In the actual piezoelectric oscillator 2, each piezoelectric layer is integrated to such an extent that the boundaries between each piezoelectric layer are not recognizable.

[0021] Each internal electrode and each external electrode is made of a conductive material. Examples of conductive materials include Ag, Pd, Pt, or Ag-Pd alloys. Each internal electrode and each external electrode is constructed, for example, as a sintered body of a conductive paste containing the above-mentioned conductive material.

[0022] The acoustic device 1 has a wiring member 25 and a pair of lead wires 26. The wiring member 25 is, for example, a flexible printed circuit board (FPC) or a flexible flat cable (FFC). The wiring member 25 extends along directions X and Y. One end of the wiring member 25 in direction X is electrically connected to each external electrode of the piezoelectric vibrator 2. The other end of the wiring member 25 in direction X is electrically connected to one end of each lead wire 26. Each lead wire 26 is a wire that is electrically connected to the piezoelectric vibrator 2 via the wiring member 25. The other end of each lead wire 26 is electrically connected to, for example, a control unit (not shown) of the acoustic device 1. The control unit sends a voltage signal to the piezoelectric vibrator 2 via the lead wires 26 and the wiring member 25. Based on the voltage signal, a voltage is applied to the external electrodes, and the piezoelectric vibrator 2 vibrates.

[0023] The vibration panel 3 is a plate member that vibrates when the vibration of the piezoelectric vibrator 2, that is, the repeated displacement of the piezoelectric vibrator 2, is transmitted to it. The vibration panel 3 extends along directions X and Y. As shown in Figure 2, the vibration panel 3 has an outer main surface 31, an inner main surface 32, and end surfaces 33, 34, 35, and 35. The outer main surface 31 and the inner main surface 32 face each other in direction Z. The outer main surface 31 is located above the inner main surface 32 in direction Z. The outer main surface 31 faces the external space of the acoustic device 1. The inner main surface 32 faces the internal space 80. The outer main surface 31 and the inner main surface 32 have a rectangular shape when viewed from direction Z. The outer main surface 31 and the inner main surface 32 each have a pair of long sides and a pair of short sides. The vibration panel 3 is positioned on the end face 46 of the frame 40, which will be described later, such that the long sides of the outer main surface 31 and the inner main surface 32 are aligned with direction X, and the short sides of the outer main surface 31 and the inner main surface 32 are aligned with direction Y. End faces 33 and 34 are surfaces that extend along direction X. End faces 35 and 36 are surfaces that extend along direction Y.

[0024] The width of the vibration panel 3 in direction X may be 86 mm or more and 200 mm or less. The width of the vibration panel 3 in direction Y may be 50 mm or more and 100 mm or less. The thickness of the vibration panel 3 in direction Z may be 0.2 mm or more and 1 mm or less. The thickness of the vibration panel 3 in direction Z may be uniform throughout the vibration panel 3. The vibration panel 3 may be made of resin or metal. The resin making up the vibration panel 3 may be polycarbonate resin or PEEK (polyetheretherketone) resin. The metal making up the vibration panel 3 may be stainless steel (e.g., SUS304) or Ni-Fe alloy (e.g., 42 alloy). The elastic modulus of the material making up the vibration panel 3 may be smaller than the elastic modulus of the material making up the housing 4. That is, the vibration panel 3 may be more elastically deformable than the housing 4.

[0025] In this embodiment, both ends of the vibration panel 3 in direction X are fixed to the frame 40. In this embodiment, as shown in Figure 3, the regions 32a and 32b of the inner main surface 32 that overlap with the end surface 46 in direction Z are fixed to the end surface 46, for example, by adhesive. As a result, the vibration panel 3 vibrates up and down along direction Z with both ends in direction X fixed to the housing 4. In direction Y, both ends of the vibration panel 3 may or may not be fixed to the frame 40. In this embodiment, both ends of the vibration panel 3 in direction Y are not fixed to the frame 40, and a gap 85 is formed between these ends and the frame 40.

[0026] Here, the gap 85 will be described with reference to Figure 5. Figure 5 is an enlarged view showing the gap 85 between the vibration panel 3 and the frame 40. In Figure 5, the gap 85 is shown between the end face 33 side of the vibration panel 3 in direction Y and the wall portion 42 of the frame 40, which will be described later. As shown in Figure 5, the end face 33 is located inside the acoustic device 1 from the wall portion 42 so as not to overlap with the wall portion 42 when viewed from direction Z. As a result, a gap 85 is formed between the end face 33 side of the vibration panel 3 and the wall portion 42. The gap 85 connects the internal space 80 and the external space of the acoustic device 1. The distance from the end face 33 to the wall portion 42 in direction Y, i.e., the width W1 of the gap 85, may be 0.2 mm or more and 10 mm or less. A gap similar to the gap 85 is also formed between the end face 34 side of the vibration panel 3 and the wall portion 43 in direction Y. The configuration of the gap 85 is not limited to the configuration described above. For example, a step may be formed on the end face 46 of the wall portion 42, 43, and the vibration panel 3 may be placed on the step. When a step is formed on the end face 46, a gap having a width in direction Z is formed between the end face 46 and the vibration panel 3 on the end face 46.

[0027] The sound generated from the vibration panel 3 can also be transmitted inside the housing 4. The sound transmitted inside the housing 4 is reflected within the housing 4. The reflected sound traveling from inside the housing 4 to the vibration panel 3 escapes to the outside of the acoustic device 1 through the gap 85. Therefore, the vibrations of the reflected sound are less likely to affect the vibration of the vibration panel 3.

[0028] The housing 4 defines an internal space 80 together with the vibration panel 3. The housing 4 has a frame 40 and a base 50. The frame 40 defines a first space 81 together with the vibration panel 3. The frame 40 is positioned on the partition 6 so as to sandwich the partition 6 between the base 50. The frame 40 is fixed to the partition 6, for example, by adhesive. As shown in Figure 2, the frame 40 has a frame wall 41. The frame wall 41 is positioned so as to surround the piezoelectric vibrator 2 when viewed from direction Z. The outer contour of the frame wall 41 is rectangular when viewed from direction Z. The frame 40 is positioned such that the long side of the outer contour of the frame wall 41 is along direction X and the short side is along direction Y.

[0029] The frame wall 41 has a plurality of wall sections 42, 43, 44, and 45. In this embodiment, the frame wall 41 has four wall sections 42, 43, 44, and 45. Wall sections 42 and 43 each extend along direction X. Wall sections 42 and 43 are spaced apart in direction Y and face each other. Wall sections 44 and 45 each extend along direction Y. Wall sections 44 and 45 are spaced apart in direction X and face each other. The frame body 40 has a pair of end faces 46 and 47 that face each other in direction Z. Each end face 46 and 47 is composed of the end faces of the four wall sections 42, 43, 44, and 45 in direction Z. End face 46 is located above end face 47 in direction Z.

[0030] The base portion 50 defines the second space 82. The base portion 50 is a box member having an opening on its upper side. As shown in Figure 2, the base portion 50 has a bottom wall 51 and side walls 52. The bottom wall 51 extends along directions X and Y. The bottom wall 51 has a rectangular shape when viewed from direction Z. The base portion 50 is arranged such that the longer side of the bottom wall 51 is along direction X and the shorter side is along direction Y. The side wall 52 extends in direction Z, intersecting the bottom wall 51. The bottom wall 51 and the side wall 52 are formed integrally.

[0031] The side wall 52 has a plurality of wall portions 53, 54, 55, and 56. In this embodiment, the side wall 52 has four wall portions 53, 54, 55, and 56. Wall portions 53 and 54 each extend along direction X. Wall portions 53 and 54 are spaced apart in direction Y and face each other. Each wall portion 55 and 56 extends along direction Y. Wall portions 55 and 56 are spaced apart in direction X and face each other. The side wall 52 has an end face 57 located on the upper part of the base portion 50 in direction Z. The end face 57 is composed of the end faces of the four wall portions 53, 54, 55, and 56 in direction Z.

[0032] The partition 6 divides the internal space 80 into multiple spaces. In this embodiment, the partition 6 divides the internal space 80 into a first space 81 and a second space located further away from the vibration panel 3 than the first space 81. The partition 6 faces the vibration panel 3 directly or indirectly in direction Z. When the partition 6 faces the vibration panel 3, it means that at least a part of the partition 6 faces the vibration panel 3, and the entire partition 6 does not have to face the vibration panel 3. When the partition 6 faces the vibration panel 3 directly, it means that there are no intervening elements other than air between the partition 6 and the vibration panel 3. When the partition 6 faces the vibration panel 3 indirectly, it means that there are intervening elements other than air between the partition 6 and the vibration panel 3. In this embodiment, since there are no intervening elements other than air between the partition 6 and the vibration panel 3 in the internal space 80, the partition 6 faces the vibration panel 3 directly in the internal space 80.

[0033] The partition 6 extends along directions X and Y. The partition 6 is a member that divides the internal space 80 into multiple spaces, and the entire partition 6 does not have to extend along directions X and Y. For example, the partition 6 may have a wall portion that extends along direction Z and is in contact with the bottom wall 51. The partition 6 has a pair of main surfaces 61, 62 and end surfaces 63, 64, 65, 66. The pair of main surfaces 61, 62 face each other in direction Z. Main surface 61 is located above main surface 62 in direction Z. Each main surface 61, 62 has a rectangular shape when viewed from direction Z. Each main surface 61, 62 has a pair of long sides and a pair of short sides. The partition 6 is positioned on the end surface 57 such that the long sides of each main surface 61, 62 are along direction X and the short sides of each main surface 61, 62 are along direction Y. End faces 63 and 64 are surfaces that extend along direction X. End faces 65 and 66 are surfaces that extend along direction Y.

[0034] The width of partition 6 in direction X may be 106 mm or more and 220 mm or less. The width of partition 6 in direction Y may be 70 mm or more and 120 mm or less. The thickness of partition 6 in direction Z may be 0.5 mm or more and 2 mm or less. The thickness of partition 6 in direction Z may be uniform throughout partition 6. Partition 6 may be made of resin or metal. The resin making up partition 6 may be polycarbonate resin or PEEK (polyetheretherketone) resin. The metal making up partition 6 may be stainless steel (e.g., SUS304) or aluminum. Partition 6 may be made of the same or different material as the vibration panel 3. The elastic modulus of the material making up partition 6 may be greater than the elastic modulus of the material making up vibration panel 3. That is, partition 6 may be less elastically deformable than vibration panel 3. The ends of partition 6 in directions X and Y are fixed to the base portion 50. In this embodiment, the portion of the main surface 62 that overlaps with the end surface 57 in direction Z is fixed to the end surface 57, for example, by an adhesive.

[0035] The partition 6 has a region A in which at least one through-hole 67 is formed. In this embodiment, multiple through-holes 67 are formed. Region A is shown by a dashed line in Figures 2 and 4. Each through-hole 67 connects multiple spaces partitioned by the partition 6. In this embodiment, each through-hole 67 is formed from the main surface 61 toward the main surface 62 and connects the first space 81 and the second space 82. In this embodiment, each through-hole 67 has a circular shape when viewed from direction Z. The radius of the circle may be 1 mm or more and 5 mm or less. The shape of each through-hole 67 is not limited and may be elliptical, rectangular or polygonal when viewed from direction Z.

[0036] In this embodiment, the partition 6 has three rows in the direction Y, each consisting of five through-holes 67 arranged along the direction X. The partition 6 has a total of 15 through-holes 67, but the number of through-holes 67 is not limited. In the following, each row of through-holes 67 will be described as the 1st row, 2nd row, and 3rd row, in order from the row closest to the end face 63 in the direction Y. That is, the row closest to the end face 64 in the direction Y is the 3rd row.

[0037] In this embodiment, the multiple through holes 67 are located towards the center of the partition 6. The multiple through holes 67 are positioned such that the distance between adjacent through holes 67 is equal in directions X and Y. The positions of the multiple through holes 67 are not limited. For example, the multiple through holes 67 may be scattered at irregular positions throughout the partition 6, or they may be located closer to the end faces 63, 64, 65, and 66 than the center of the partition 6.

[0038] Region A is a region in which multiple through holes 67 are formed. Region A faces the piezoelectric vibrator 2, as shown in Figure 4. As a result, at least one of the multiple through holes 67 may overlap with the piezoelectric vibrator 2 in direction Z. In this embodiment, each through hole 67 in the second row overlaps with the piezoelectric vibrator 2 as a whole. Each through hole 67 in the first and third rows overlaps with the piezoelectric vibrator 2 in part.

[0039] Next, the method for adjusting the sound pressure of the sound generated from the vibration panel 3 and the effect of the acoustic device 1 will be explained. As shown in Figure 3, the internal space 80 is divided into a first space 81 and a second space 82 by a partition 6. The first space 81 is surrounded by the vibration panel 3, the frame 40, and the partition 6. The second space 82 is surrounded by the partition 6 and the base 50. As described above, the second space 82 is located further away from the vibration panel 3 than the first space 81, and is in communication with the first space 81 through a plurality of through holes 67. Therefore, the sound generated from the vibration panel 3 is transmitted to the second space 82 through the first space 81 and the plurality of through holes 67.

[0040] The multiple through holes 67 and the second space 82 constitute a Helmholtz resonator. The Helmholtz resonance frequency f of this Helmholtz resonator H This is expressed by the following equation (1).

[0041]

number

[0042] In equation (1), ν is the speed of sound. S is the sum of the areas of each through-hole 67 as viewed from direction Z. V is the volume of the second space 82. In this embodiment, volume V is the volume of the space enclosed by the bottom wall 51, the side walls 52 and the partition 6. L is the length of each through-hole 67 in direction Z. In this embodiment, length L is the thickness of the partition 6 in direction Z. R is the radius of the circle with area S. That is, radius R is obtained by the square root of S / π. Radius R is the opening end correction value.

[0043] The sound pressure of the sound generated from the vibrating panel 3 can be increased or decreased by a Helmholtz resonator composed of multiple through holes 67 and a second space 82. Specifically, the vibration frequency f0 of the sound generated from the vibrating panel 3 can be increased or decreased by the Helmholtz resonance frequency f H When this is the case, the sound pressure of the sound generated from the vibrating panel 3 is increased by the Helmholtz resonator described above. Therefore, when the vibration frequency f0 matches the Helmholtz resonance frequency fH By designing the acoustic device 1 to match this, the sound pressure of the sound generated from the acoustic device 1 can be increased. In this embodiment, the sound pressure, which has been increased in the internal space 80, is released to the outside of the acoustic device 1 through the gap 85.

[0044] The vibration frequency f0 is the Helmholtz resonance frequency f H If it is smaller than the Helmholtz resonance frequency f, the sound pressure of the sound generated from the vibrating panel 3 is reduced by the Helmholtz resonator described above. Therefore, when the vibration frequency f0 is smaller than the Helmholtz resonance frequency f H By designing acoustic device 1 to be smaller than this, the sound pressure of the sound generated from acoustic device 1 can be reduced.

[0045] Helmholtz resonance frequency f H As described above using equation (1), the Helmholtz resonance frequency f changes depending on the volume V of the second space 82, the sum of the areas S of each through-hole 67, and the length L of each through-hole 67 in direction Z. Therefore, by designing the acoustic device 1 by appropriately adjusting the volume V, the sum S, and the length L, the desired Helmholtz resonance frequency f can be achieved. H This can be achieved. The volume V can be adjusted, for example, by changing the size of the base portion 50. The total value S can be adjusted by changing the number or size of the through holes 67. The length L can be adjusted by changing the thickness of the partition 6.

[0046] In the acoustic device 1 according to this embodiment, the internal space 80 is divided into multiple spaces by a partition 6. The divided spaces are connected by at least one through-hole 67. Therefore, sound generated from the vibrating panel 3 enters the spaces divided by the partition 6 through at least one through-hole 67. The at least one through-hole 67 into which sound enters and the spaces connected to the through-hole 67 constitute a Helmholtz resonator, which can increase or decrease sound pressure. Thus, the acoustic device 1 according to this embodiment can adjust the sound pressure of the sound generated from the vibrating panel 3.

[0047] The piezoelectric vibrator 2 is positioned on the vibration panel 3. The partition 6 has a region A in which at least one through hole 67 is formed. Region A faces the piezoelectric vibrator 2. When region A faces the piezoelectric vibrator 2, sound generated from the vibrating panel 3 can easily enter the Helmholtz resonator, which is formed by at least one through-hole 67 in region A and the space connected to the through-hole 67. Therefore, the sound pressure can be efficiently adjusted by the Helmholtz resonator.

[0048] The partition 6 has multiple through holes 67, each containing at least one through hole 67. If multiple through holes 67 are formed in the partition 6, it becomes possible to adjust the shape and position of each of the multiple through holes 67. Therefore, the desired Helmholtz resonance frequency f H This could facilitate the design of the acoustic device 1 needed to achieve this.

[0049] The partition 6 divides the internal space 80 into two spaces. The housing 4 has a frame 40 that defines one of the two spaces (first space 81) together with the vibration panel 3, and a base portion 50 that defines the other of the two spaces (second space 82). The base portion 50 includes a bottom wall 51 and a side wall 52 that extends in a direction Z intersecting the bottom wall 51. The partition 6 has a flat plate shape and is positioned on the end face 57 of the side wall 52. The frame 40 is positioned on the partition 6 so as to sandwich the partition 6 between its end face 57. The fact that the frame 40 and the base 50, which are positioned to sandwich the partition 6, are separate components makes it easier to manufacture the acoustic device 1.

[0050] <First variation> Referring to FIG. 6, the acoustic device 100 according to the first modification will be described. FIG. 6 is a diagram showing a cross-sectional configuration of the acoustic device 100 according to the first modification. The cross-section shown in FIG. 6 is a cross-section when the acoustic device 100 is cut along the planes in the directions X and Z. In the description of the acoustic device 100, mainly the differences from the above-described acoustic device 1 will be described, and the common points may be omitted from the description.

[0051] The acoustic device 100 is different from the acoustic device 1 in that it includes a sound-absorbing member 70. The sound-absorbing member 70 absorbs the sound transmitted from the vibration panel 3 to the internal space 80. In this modification, the sound-absorbing member 70 is disposed on the inner surface of the bottom wall 51 and the inner surface of the side wall 52. The inner surface of the bottom wall 51 refers to the portion of the surface of the bottom wall 51 facing the internal space 80. The inner surface of the side wall 52 refers to the portion of the surface of the side wall 52 facing the internal space 80. In the present embodiment, the sound-absorbing member 70 is disposed over the entire inner surface of the bottom wall 51 and the inner surface of the side wall 52. The sound-absorbing member 70 does not have to be disposed over the entire inner surface of the bottom wall 51 and the inner surface of the side wall 52. For example, the sound-absorbing member 70 may be disposed only in the region of the inner surface of the bottom wall 51 that overlaps with the piezoelectric vibrator 2 in the direction Z. The sound-absorbing member 70 is fixed to the inner surface of the bottom wall 51 and the inner surface of the side wall 52 by, for example, an adhesive. The sound-absorbing member 70 may be disposed on the inner surface of the frame wall 41. The inner surface of the frame wall 41 refers to the portion of the surface of the frame wall 41 facing the internal space 80.

[0052] The sound-absorbing member 70 may be a porous sound-absorbing material. A porous sound-absorbing material is a sound-absorbing material in which a large number of holes are formed inside the base member. The material constituting the sound-absorbing member 70 may be a urethane resin or ethylene-propylene-diene rubber (EPDM). The thickness of the sound-absorbing member 70 may be 5 mm or more and 10 mm or less.

[0053] The Helmholtz resonance frequency f in the acoustic device 100 HThe volume V used to determine this volume may be the volume of the second space 82 minus the volume of the sound-absorbing member 70. In other words, the volume V may be the volume of the space enclosed by the bottom wall 51, the side walls 52, and the partition 6 minus the volume of the sound-absorbing member 70.

[0054] <Second variation> Referring to Figure 7, the acoustic device 200 according to the second modified example will be described. Figure 7 is a diagram showing the cross-sectional configuration of the acoustic device 200 according to the second modified example. The cross-section shown in Figure 7 is a cross-section obtained when the acoustic device 200 is cut by planes along directions X and Z. In describing the acoustic device 200, the differences from the acoustic device 1 described above will be mainly explained, and common points may be omitted from the explanation.

[0055] The acoustic device 200 differs from the acoustic device 1 mainly in that the piezoelectric vibrator 2 is positioned on the inner main surface 32 and located in the internal space 80. The orientation of the piezoelectric vibrator 2 in the acoustic device 200 is different from that of the piezoelectric vibrator 2 in the acoustic device 1. Specifically, the piezoelectric vibrator 2 is inverted, and the main surface 21 is located below the main surface 22 in direction Z. The main surface 21 faces the partition 6 in direction Z.

[0056] The frame 40 has a pair of through holes 49 through which a pair of lead wires 26 are inserted. In Figure 7, only one of the pair of through holes 49 is shown, but the other through hole 49 is located at the back of the page. Each through hole 49 extends along direction X and connects the internal space 80 with the external space of the acoustic device 200. The number and shape of the through holes 49 are not limited. The frame 40 may have a single through hole through which multiple lead wires 26 are inserted together, or it may have multiple through holes through which multiple lead wires 26 are inserted, as in this modified example.

[0057] In this modified example, each through-hole 49 is formed in the wall portion 45. The position of each through-hole 49 is not limited. Each through-hole 49 may be formed in the wall portions 42, 43, and 44. Each through-hole 49 may also be a notch formed in the end face 46. If each through-hole 49 is a notch formed in the end face 46, each lead wire 26 inserted through each through-hole 49 is positioned between the frame wall 41 and the vibration panel 3. In this case, the size of each through-hole 49 may be made larger than the diameter of each lead wire 26 so that the vibration of the vibration panel 3 is not hindered by each lead wire 26 contacting the vibration panel 3, and each lead wire 26 does not come into contact with the vibration panel 3. Each through-hole 49 may also be a notch formed in the end face 47. If each through-hole 49 is a notch formed in the end face 47, each lead wire 26 inserted through each through-hole 49 is positioned between the frame wall 41 and the partition 6.

[0058] In the second modified example, the vibration panel 3 has an inner main surface 32 facing the internal space 80. The piezoelectric vibrator 2 is arranged on the inner main surface 32. When the piezoelectric vibrator 2 is positioned on the inner main surface 32, the piezoelectric vibrator 2 is located in the internal space 80. Therefore, the piezoelectric vibrator 2 is protected from external shocks to the acoustic device 200, for example, by the vibration panel 3 and the housing 4.

[0059] The frame 40 has through holes 49 through which wiring (lead wires 26) electrically connected to the piezoelectric vibrator 2 is inserted. If the through-hole 49 is formed in the frame 40, even if the piezoelectric vibrator 2 to which the wiring is connected is located in the internal space 80, the wiring is positioned from the internal space 80 to the external space of the acoustic device 200 through the through-hole 49. Therefore, the degree of freedom in positioning the piezoelectric vibrator 2 and the wiring is improved.

[0060] While embodiments of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0061] For example, the shape of the acoustic device 1 may be cubic or cylindrical. If the shape of the acoustic device 1 is cubic or cylindrical, the shapes of the vibration panel 3 and the partition 6 may be square or circular when viewed from direction Z.

[0062] In the above embodiments and modifications, the frame 40 is formed separately from the base portion 50, but the frame 40 may be formed integrally with the base portion 50. In the above embodiments and modifications, the partition 6 is formed separately from the frame 40 and the base portion 50, but the partition 6 may be formed integrally with at least one of the frame 40 and the base portion 50.

[0063] In the above embodiments and modifications, the partition 6 is arranged parallel to the XY plane, but it may also be arranged at an angle to the XY plane.

[0064] In the second modified example described above, each lead wire 26 is inserted through each through hole 49, but it may also be arranged so as to be sandwiched between the vibration panel 3 and the frame 40 without being inserted through each through hole 49, or it may be arranged so as to be sandwiched between the frame 40 and the partition 6. Each lead wire 26 may also be arranged to pass through the gap 85. [Explanation of Symbols]

[0065] 1,100,200...Acoustic device, 2...Piezoelectric vibrator, 3...Vibration panel, 4...Housing, 6...Partition, 21,22...Main surface, 25...Wiring member, 26...Lead wire, 31...Outer main surface, 32...Inner main surface, 33,34,35,36...End surface, 40...Frame, 41...Frame wall, 42,43,44,45...Wall section, 46,47...End surface, 49...Through hole, 50...Base section, 51...Bottom wall, 52...Side wall, 53,54,55,56...Wall section, 57...End surface, 61,62...Main surface, 63,64,65,66...End surface, 67...Through hole, 70...Sound absorbing member, 80...Internal space, 81...First space, 82...Second space, 85...Gap, A...Area.

Claims

1. Piezoelectric vibrator and A vibrating panel that vibrates using a piezoelectric vibrator, A housing is configured to define an internal space together with the vibration panel, and to form a gap between it and the end of the vibration panel, An acoustic device comprising a partition positioned opposite the vibration panel, which divides the internal space into multiple spaces, The partition has at least one through-hole that connects the multiple spaces, The vibration panel has an outer main surface and an inner main surface that face each other, The aforementioned outer main surface faces the external space of the acoustic device, The aforementioned inner main surface faces the aforementioned internal space. Audio device.

2. The piezoelectric vibrator is arranged on the vibration panel, The partition has a region in which at least one through hole is formed, and this region faces the piezoelectric vibrator. The acoustic device according to claim 1.

3. The partition has a plurality of through holes, including at least one through hole. The acoustic device according to claim 1 or 2.

4. The piezoelectric vibrator is arranged on the inner main surface, The acoustic device according to any one of claims 1 to 3.

5. The partition divides the internal space into two spaces. The housing comprises a frame that defines one of the two spaces together with the vibration panel, and a base that defines the other of the two spaces. The base portion includes a bottom wall and side walls extending in a direction intersecting the bottom wall. The partition has a flat plate shape and is positioned on the end face of the side wall. The frame is positioned on the partition such that it sandwiches the partition between its end face and the partition. The acoustic device according to any one of claims 1 to 4.

6. The frame has through holes through which wiring electrically connected to the piezoelectric vibrator is inserted. The acoustic device according to claim 5.

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