Acoustic device

Abstract

An acoustic device (1) is provided with a matching part (100) provided to an inner wall surface of a housing (90), the matching part (100) matching acoustic impedances in order to propagate sound from a sound source (50) provided inside the housing (90) to the outside of the housing (90). The matching part (100) has a support frame (20) provided to the inner wall surface of the housing (90), and a vibration membrane (10) supported by the support frame (20). The support frame (20) is disposed away from the sound source (50).

Description

sound equipment

[0001] The present invention relates to an acoustic device.

[0002] An acoustic device is a device that propagates sound from a sound source. For example, an acoustic device includes a sound source and a housing that houses the sound source. The housing obstructs the propagation of sound. For this reason, acoustic devices require a method for propagating sound through the housing.

[0003] For example, Patent Document 1 discloses an ultrasonic transducer including a first acoustic transducer, a second acoustic transducer, and a cylindrical housing with a bottom. The second acoustic transducer has a second membrane portion, an annular portion that supports the second membrane portion, and an acoustic matching plate that faces the second membrane portion with a gap therebetween and forms a sealed space between the second membrane portion and the housing.

[0004] International Publication No. 2021 / 192417

[0005] As a measure to increase the sound propagating to the outside, for example, increasing the drive voltage of the sound source, drilling holes in the housing to serve as a sound propagation path, etc. However, increasing the drive voltage of the sound source may reduce reliability, and drilling holes in the housing may affect the appearance, making it look unattractive, or reducing waterproof and dustproof functions.

[0006] According to the ultrasonic transducer described in Patent Document 1, the second acoustic transducer matches the acoustic impedance of the ultrasonic waves emitted from the first acoustic transducer with that of the external medium. This allows for increased sound propagation to the outside without causing a decrease in reliability due to an increase in drive voltage or a decrease in waterproof or dustproof functionality due to holes in the housing. However, the ultrasonic transducer described in Patent Document 1 integrates a sound source and a matching section that matches the acoustic impedance of the sound emitted by the sound source, which can limit the design freedom of an acoustic device including the ultrasonic transducer. Furthermore, the ultrasonic transducer must be attached exposed to the acoustic device, which can limit the installation freedom.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide an acoustic device with improved freedom in design and installation.

[0008] An acoustic device according to one aspect of the present invention includes a matching section provided on an inner wall surface of a housing, which matches acoustic impedance so that sound from a sound source provided inside the housing is propagated to the outside of the housing, and the matching section has a support frame provided on the inner wall surface of the housing and a vibration membrane supported by the support frame, and the support frame is positioned away from the sound source.

[0009] Another aspect of the present invention provides an acoustic device comprising a sound source provided inside a housing, and a matching unit provided on an inner wall surface of the housing that matches acoustic impedance to propagate sound from the sound source to the outside of the housing, the matching unit having a support frame provided on the inner wall surface of the housing and a vibration membrane supported by the support frame, the support frame being positioned away from the sound source.

[0010] Another aspect of the present invention provides an acoustic device comprising a housing, a sound source provided inside the housing, and a matching unit provided on the inner wall surface of the housing that matches acoustic impedance to propagate sound from the sound source to the outside of the housing, the matching unit having a support frame provided on the inner wall surface of the housing and a vibration membrane supported by the support frame, the support frame being positioned away from the sound source.

[0011] According to the present invention, it is possible to provide an acoustic device with improved freedom in design and installation.

[0012] FIG. 1 is an exploded perspective view of an acoustic device according to a first embodiment; FIG. 2 is a cross-sectional view of an acoustic device according to the first embodiment; FIG. 3 is a graph showing the results of a simulation in the first embodiment; FIG. 4 is a cross-sectional view of an acoustic device according to a second embodiment; FIG. 5 is a graph showing the results of a simulation in the second embodiment; FIG. 6 is a cross-sectional view of an acoustic device according to a third embodiment; FIG. 7 is a cross-sectional view of an acoustic device according to a fourth embodiment; FIG. 8 is a cross-sectional view of an acoustic device according to a fifth embodiment; and FIG. 9 is a cross-sectional view of an acoustic device according to a sixth embodiment.

[0013] Hereinafter, embodiments of the present invention will be described. In the following description of the drawings, the same or similar components are denoted by the same or similar reference numerals. The drawings are illustrative, and the dimensions and shapes of each part are schematic. The technical scope of the present invention should not be interpreted as being limited to the embodiments.

[0014] First Embodiment First, the configuration of an acoustic device according to a first embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is an exploded perspective view of the acoustic device according to the first embodiment. Fig. 2 is a cross-sectional view of the acoustic device according to the first embodiment.

[0015] The acoustic device 1 includes a housing 90 , a matching section 100 , and a sound-generating component 200 .

[0016] The housing 90 is a container that houses the matching unit 100 and the sound-generating component 200 in its internal space, and is specifically a housing for a sound-emitting product, such as a home appliance or a mobile device. The housing 90 seals the internal space. The shape of the housing 90 is, for example, cylindrical. The materials of the main wall portions 91, 92 and the side wall portion 93 are not particularly limited and may be appropriately selected from metal, ceramic, semiconductor, resin, etc. The materials of the main wall portions 91, 92 and the side wall portion 93 are, for example, the same, but may also be different from each other.

[0017] The housing 90 has main wall portions 91 and 92 and a side wall portion 93. The main wall portion 91 and the main wall portion 92 face each other. The main wall portions 91 and 92 are disk-shaped. One end of the side wall portion 93 is connected to an end of the main wall portion 91, and the other end of the side wall portion 93 is connected to an end of the main wall portion 92. In other words, the side wall portion 93 connects the end of the main wall portion 91 and the end of the main wall portion 92. The side wall portion 93 is cylindrical in shape.

[0018] The main wall portion 91 has an inner wall surface 91A provided on the side facing the main wall portion 92 and the side wall portion 93, and an outer wall surface 91B provided on the opposite side from the inner wall surface 91A. The main wall portion 92 has an inner wall surface 92A provided on the side facing the main wall portion 91 and the side wall portion 93, and an outer wall surface 92B provided on the opposite side from the inner wall surface 92A. The side wall portion 93 has an inner wall surface 93A provided on the side facing the main wall portions 91 and 92, and an outer wall surface 93B provided on the opposite side from the inner wall surface 93A. The inner wall surfaces 91A, 92A, and 93A are inner surfaces of the housing 90 that surround the internal space in which the matching portion 100 and the sound-producing component 200 are housed. The outer wall surfaces 91B, 92B, and 93B are outer surfaces of the housing 90 that are exposed to the external space.

[0019] The housing is not limited to a configuration in which the internal space is sealed. The housing does not have to be sealed, i.e., the internal space of the housing may be connected to the external space. In this case, a cylindrical or slit-shaped hole may be formed in the main wall or side wall of the housing. The shape of the housing is not limited to a cylindrical shape as long as it can accommodate the matching section and the sound-generating components, and may be, for example, a polygonal cylinder, an elliptical cylinder, a polygonal truncated pyramid, a circular truncated cone, an elliptical truncated cone, a sphere, an elliptical sphere, or a combination thereof.

[0020] The matching unit 100 propagates sound from a sound source 50 (described later) included in the sound-generating component 200 through the housing 90. The matching unit 100 is provided on an inner wall surface 91A of the main wall 91. The matching unit 100 matches the acoustic impedance of a gas filling the internal space of the housing 90 with the acoustic impedance of the main wall 91 of the housing 90 at the acoustic frequency of the sound source 50. The gas in the internal space of the housing 90 is, for example, air, and the acoustic impedance of air is significantly different from the acoustic impedance of the main wall 91 of the housing 90. Sound is reflected at the boundary between media with significantly different acoustic impedances, but because the matching unit 100 matches the acoustic impedances, reflection of sound at the inner wall surface 91A of the main wall 91 is suppressed. In other words, the matching unit 100 efficiently propagates sound emitted from the sound source 50 in the internal space of the housing 90 to the external space of the housing 90.

[0021] The internal space of housing 90 is filled with, for example, air, but is not limited to this as long as it is filled with a fluid that can propagate the sound emitted by sound-generating component 200. The fluid filling the internal space of housing 90 may be an inert gas such as a rare gas or nitrogen gas, a mixed gas containing air, or a liquid such as water.

[0022] The matching section 100 includes a support frame 20 and a vibration membrane 10 .

[0023] The support frame 20 is provided on an inner wall surface 91A of the main wall portion 91 of the housing 90. The support frame 20 supports the vibration membrane 10. The support frame 20 has a tubular shape, for example, a cylindrical shape. The material of the support frame 20 is not particularly limited, and may be appropriately selected from metal, ceramic, semiconductor, resin, etc.

[0024] The support frame 20 has end faces 21 and 22, an inner surface 20A, and an outer surface 20B.

[0025] The end face 21 is a surface that connects the inner surface 20A and the outer surface 20B on the side facing the main wall portion 91, and is provided in a frame shape. The end face 22 is a surface that connects the inner surface 20A and the outer surface 20B on the side facing the main wall portion 92, and is provided in a frame shape. The end face 21 is connected to the inner wall surface 91A of the main wall portion 91 of the housing 90. In other words, the end of the support frame 20 on the end face 21 side is a closed end closed by the inner wall surface 91A. The end face 22 is provided away from the housing 90 and the sound-generating component 200, and is exposed to the internal space of the housing 90. In other words, the end of the support frame 20 on the end face 22 side is an open end that is open to the internal space of the housing 90. The end of the support frame 20 on the end face 21 side corresponds to an example of "one end of the support frame," and the end of the support frame 20 on the end face 22 side corresponds to an example of "the other end of the support frame."

[0026] The inner surface 20A is a side surface provided on the opposite side to the outer surface 20B. The outer surface 20B is a side surface provided on the side facing the side wall portion 93 of the housing 90. The vibration membrane 10 is connected to a position away from both the end surface 21 and the end surface 22 of the inner surface 20A. Although not shown, an adhesive for fixing the support frame 20 to the housing 90 may be provided on the outer surface 20B. In this case, the adhesive is provided in a fillet shape along the outer surface 20B of the support frame 20 and the inner wall surface 91A of the main wall portion 91 of the housing 90. The adhesive may be provided between the inner wall surface 91A of the main wall portion 91 of the housing 90 and the end surface 21 of the support frame 20. Note that the outer surface 20B may be provided with an attachment portion for attaching the support frame 20 to the housing 90. In this case, the matching portion may be attached to the inner wall surface of the housing via the attachment portion by engagement, fitting, screwing, or the like.

[0027] The diaphragm 10 is supported by the support frame 20. Specifically, the diaphragm 10 is connected to the inner surface 20A of the support frame 20 around the entire periphery. The diaphragm 10 is provided at a predetermined distance from the inner wall surface 91A of the main wall portion 91 of the housing 90. The diaphragm 10 divides the space surrounded by the inner surface 20A of the support frame 20 into a space on the end surface 21 side and a space on the end surface 22 side. The space surrounded by the main wall portion 91 of the housing 90, the support frame 20, and the diaphragm 10 is sealed. When viewed from above in the direction in which the main wall portion 91 and the main wall portion 92 overlap (hereinafter simply referred to as "planar view"), the center of the diaphragm 10 overlaps with the centers of the main wall portions 91 and 92 of the housing 90, for example, but is not limited thereto. In the planar view, the center of the diaphragm 10 may be spaced apart from the centers of the main wall portions 91 and 92.

[0028] The diaphragm 10 has a thickness along the direction in which the main wall portions 91 and 92 face each other, and has a main surface extending along the inner wall surfaces 91A and 92A of the main wall portions 91 and 92. When the direction in which the diaphragm 10 has a thickness is defined as the "thickness direction," the diaphragm 10 is held by the support frame 20 so as to be vibrable in the thickness direction. When the diaphragm 10 is vibrated by sound propagated from the sound-producing component 200, the matching unit 100 matches the acoustic impedance of the internal space of the housing 90 with the acoustic impedance of the main wall portion 91 of the housing 90. The material of the diaphragm 10 is not particularly limited and may be appropriately selected from metal, ceramic, semiconductor, resin, and the like. The material, mass, position, and the like of the diaphragm 10 are appropriately designed depending on the acoustic frequency of the sound-producing component 200 whose acoustic impedance is to be matched, the acoustic impedance of the gas in the internal space of the housing 90, the acoustic impedance of the main wall portion 91 of the housing 90, and the like.

[0029] The sound-generating component 200 generates sound. The sound-generating component 200 is provided, for example, on the inner wall surface 92A that faces the inner wall surface 91A on which the matching portion 100 is provided.

[0030] The arrangement of the sound-making component 200 is not limited to the above. The sound-making component 200 may be provided on the inner wall surface 93A or the inner wall surface 91A.

[0031] The sound-producing component 200 includes a sound source 50 and a substrate 60 .

[0032] The sound source 50 is a piezoelectric vibration element having, for example, quartz crystal, PZT, AlN, lithium niobate, or lithium tantalate as a piezoelectric material. The sound source 50 is provided, for example, on the side of the substrate 60 facing the matching unit 100. The sound source 50 is disposed away from the support frame 20. When viewed from above in the thickness direction of the vibration membrane 10, the sound source 50 overlaps with the matching unit 100. In other words, the sound source 50 is provided at a distance from the support frame 20 in the thickness direction of the vibration membrane 10. When viewed from above, the center of the sound source 50 overlaps with the center of the main wall portions 91, 92 of the housing 90.

[0033] The sound source is not limited to the above. When the sound source is a vibration element, the driving force that vibrates the sound source may be electrostatic force or electromagnetic force. The sound source may be a buzzer with a case or a speaker. The position of the sound source is not limited to the above as long as it is placed away from the matching part. When viewed in a plan view, the center of the sound source may be placed away from the center of the main wall part of the housing. The sound source may be placed in any position relative to the matching part as long as it is placed in the internal space of the housing.

[0034] The substrate 60 is a mounting substrate on which the sound source 50 is mounted. The substrate 60 includes electrodes for applying electric signals to the sound source 50. Although not shown, wiring for connecting the sound source 50 to an external circuit is connected to the substrate 60. The substrate 60 is provided on the inner wall surface 91A, 92A, or 93A, and the sound source 50 is provided on the inner wall surface 91A, 92A, or 93A via the substrate 60.

[0035] The substrate may be omitted. In this case, the sound source is provided directly on the inner wall surface of the housing and connected to the wiring, for example.

[0036] Next, referring to FIG. 3 , the acoustic propagation efficiency in the first embodiment will be described. FIG. 3 is a graph showing the results of a simulation in the first embodiment. The horizontal axis of the graph shown in FIG. 3 , "Gap dimension [mm]," indicates the distance in the thickness direction between the support frame 20 and the sound source 50. The vertical axis of the graph shown in FIG. 3 , "Acoustic energy transmission rate," indicates the proportion of acoustic energy propagated to the external space of the housing 90 via the matching unit 100. This vertical axis is a numerical value calculated with the acoustic energy propagated to the external space of the housing 90 as a reference, i.e., 100%, in a configuration in which the sound source 50 is in contact with the support frame 20 of the matching unit 100. In the graph shown in FIG. 3 , the "Open" plot shows the simulation results when the side wall portion 93 of the housing 90 is omitted, and the "Sealed" plot shows the simulation results when the housing 90 is sealed.

[0037] (Simulation conditions) When viewed in a plan view, the diaphragm 10, sound source 50, and main wall portions 91, 92 are circular, with their centers overlapping. The matching portion 100 is provided on the main wall portion 91. The substrate 60 is omitted, and the sound source 50 is provided directly on the main wall portion 92. When simulating the "sealed" plot in which the housing 90 is sealed, the internal space of the housing 90 is filled with air. Radius of the diaphragm 10 in a plan view: 5 mm Distance between the diaphragm 10 and the main wall portion 91: 0.172 mm Mass of the diaphragm 10: 0.0958 g Radius of the area surrounded by the inner surface 20A of the support frame 20: 5 mm Radius of the area surrounded by the outer surface 20B of the support frame 20: 5.1 mm Dimension in the thickness direction of the internal space of the housing 90: 10 mm Radius of the internal space of the housing 90 in a plan view: 20 mm Density of the main wall portion 91 of the housing 90: 1050 kg / m ３ Speed ​​of sound in the main wall 91 of the housing 90: 2300 m / s Density of gas in the internal space of the housing 90: 1.144 kg / m ３ Speed ​​of sound of gas in the internal space of the housing 90: 340 m / s Acoustic frequency of the sound source 50: 4000 Hz Radius of the sound source 50 in a plan view: 5 mm Output of the sound source 50: 1 Pa Gap dimension between the support frame 20 and the sound source 50 in the thickness direction: 0 mm, 1 mm, 2 mm, 4 mm, 8 mm

[0038] As the "sealed" plot shows, when the internal space of the housing 90 is sealed, the acoustic energy transmission rate is maintained at approximately 100% and does not decrease even if the gap dimension increases. This is because even sound that does not propagate directly from the sound source 50 to the diaphragm 10 of the matching unit 100 is reflected by the inner wall surfaces 91A, 92A, and 93A of the housing 90 and propagates indirectly to the diaphragm 10 of the matching unit 100.

[0039] As the "open" plot shows, when the side wall 93 of the housing 90 is omitted, the acoustic energy transmissibility decreases as the gap dimension increases. This is because sound that does not propagate directly from the sound source 50 to the diaphragm 10 of the matching unit 100 dissipates without propagating to the diaphragm 10 of the matching unit 100. Even when the side wall 93 is omitted, the decrease in the acoustic energy transmissibility is suppressed when the gap dimension is small. Note that in this simulation, the simulation was performed with all of the side wall 93 of the housing 90 omitted, so the decrease in the acoustic energy transmissibility is large. However, when the hole opened in the housing 90 is small, the decrease in the acoustic energy transmissibility can be suppressed.

[0040] As described above, according to this embodiment, the acoustic device 1 includes a matching unit 100 provided on the inner wall surface 91A of the housing 90. The matching unit 100 matches acoustic impedance so that sound from the sound source 50 propagates through the housing 90. The matching unit 100 includes a support frame 20 provided on the inner wall surface 91A of the housing 90, and a diaphragm 10 supported by the support frame 20. The support frame 20 is disposed away from the sound source 50.

[0041] With this, the matching unit 100 does not require a wiring connection like the sound source 50, so the matching unit 100 can be positioned in the desired direction in which sound is to be propagated. Since the matching unit 100 can be freely positioned relative to the sound source 50, the degree of freedom in designing the acoustic device 1 is improved. Furthermore, the matching unit 100 can be attached to the inner wall surface 91A of the housing 90, and there is no need to drill a hole in the housing and expose a portion of it through the hole. This improves the degree of freedom in mounting the acoustic device 1. Furthermore, if the acoustic device does not have the matching unit 100, or if the acoustic device has the matching unit 100 but the sound pressure is insufficient, it is possible to install an additional matching unit 100 later and increase the sound pressure of the acoustic device.

[0042] In one aspect of this embodiment, the housing 90 seals the internal space.

[0043] This makes it possible to improve the rate of acoustic energy propagation from the acoustic device 1 to the external space.

[0044] Other embodiments will be described below. Note that components that are the same as or similar to those in the first embodiment are denoted by the same or similar reference numerals, and descriptions thereof will be omitted as appropriate. Furthermore, similar effects resulting from similar components will not be mentioned one after another.

[0045] Second Embodiment Next, the configuration of an acoustic device 2 according to a second embodiment will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view of the acoustic device according to the second embodiment.

[0046] In a plan view, the center of the sound source 50 is spaced apart from the center of the diaphragm 10. For example, in a plan view, part of the sound source 50 overlaps with the diaphragm 10, part of the sound source 50 overlaps with the support frame 20, and part of the sound source 50 is located outside the matching section 100. Note that the position of the sound source 50 is not limited to the above, and for example, the entire sound source 50 may be spaced apart from the diaphragm 10, or the entire sound source 50 may be spaced apart from the support frame 20.

[0047] Next, the acoustic propagation efficiency in the second embodiment will be described with reference to FIG. 5 . FIG. 5 is a graph showing the results of a simulation in the second embodiment. The horizontal axis "shift amount [mm]" of the graph shown in FIG. 5 represents the distance between the center of the diaphragm 10 and the center of the sound source 50 in a planar view. The vertical axis "acoustic energy transmissibility" of the graph shown in FIG. 5 represents the proportion of acoustic energy propagated into the external space of the housing 90 via the matching unit 100. This vertical axis represents a value calculated by setting the acoustic energy propagated into the external space of the housing 90 as a reference, i.e., 100%, in a configuration in which the center of the sound source 50 overlaps the center of the diaphragm 10 in a planar view.

[0048] (Simulation conditions) When viewed in a plan view, the vibration membrane 10, sound source 50, and main wall portions 91, 92 are circular, and the internal space of the housing 90 is assumed to be sealed. The matching section 100 is assumed to be provided on the main wall portion 91. The substrate 60 is assumed to be omitted, and the sound source 50 is assumed to be provided directly on the main wall portion 92. The internal space of the housing 90 is assumed to be filled with air. Radius of the vibration membrane 10 in a plan view: 5 mm Distance between the vibration membrane 10 and the main wall portion 91: 0.172 mm Mass of the vibration membrane 10: 0.0958 g Radius of the area surrounded by the inner surface 20A of the support frame 20: 5 mm Radius of the area surrounded by the outer surface 20B of the support frame 20: 5.1 mm Dimension in the thickness direction of the internal space of the housing 90: 10 mm Radius of the internal space of the housing 90 in a plan view: 20 mm Density of the main wall portion 91 of the housing 90: 1050 kg / m ３ Speed ​​of sound in the main wall 91 of the housing 90: 2300 m / s Density of gas in the internal space of the housing 90: 1.144 kg / m ３ Speed ​​of sound of gas in the internal space of the housing 90: 340 m / s Acoustic frequency of the sound source 50: 4000 Hz Radius of the sound source 50 in a planar view: 5 mm Output of the sound source 50: 1 Pa Distance (deviation amount) between the center of the diaphragm 10 and the center of the sound source 50 in a planar view: 0 mm, 10 mm, 14.8 mm

[0049] The acoustic energy transmission rate is maintained at approximately 100% and does not decrease even if the amount of deviation increases. This indicates that the position of the matching unit 100 is not limited to a position facing the sound source 50 in a plan view, and the matching unit 100 can be freely positioned within the housing 90. Even if the matching unit 100 cannot be positioned facing the sound source 50 due to the shape of the substrate 60 or the components around the sound source 50, sound can still be sufficiently propagated outside the housing 90.

[0050] Third Embodiment Next, the configuration of an acoustic device 3 according to a third embodiment will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view of the acoustic device according to the third embodiment.

[0051] The sound source 50 is aligned with the support frame 20 at a distance in a direction parallel to the inner wall surfaces 91A, 92A of the main wall portions 91, 92 of the housing 90. The sound source 50 may be aligned with the diaphragm 10 in the same direction.

[0052] This prevents interference between the matching section 100 and the sound source 50 in the thickness direction of the diaphragm 10, allowing the acoustic device 3 to be made low-profile.

[0053] Fourth Embodiment Next, the configuration of an acoustic device 4 according to a fourth embodiment will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view of the acoustic device according to the fourth embodiment.

[0054] The matching section 100 is provided on the main wall section 92 of the housing 90, and the diaphragm 10 is disposed facing the substrate 60. The substrate 60 is provided on one of the inner wall surfaces 91A, 92A, and 93A, and the main surface of the substrate 60 extends along the inner wall surfaces 91A and 92A of the main wall sections 91 and 92. The diaphragm 10 is provided on the main wall section 92 side of the substrate 60. The sound source 50 is provided on the main wall section 91 side of the substrate 60. In other words, the sound source 50 is provided on the side of the substrate 60 opposite the side facing the matching section 100. The sound emitted from the sound source 50 does not directly reach the diaphragm 10, but is reflected at least once by the inner wall surfaces 91A, 92A, and 93A of the housing 90 before reaching the diaphragm 10. Even with this arrangement, sound can be sufficiently propagated outside the housing 90.

[0055] Fifth Embodiment Next, the configuration of an acoustic device 5 according to a fifth embodiment will be described with reference to Fig. 8. Fig. 8 is a cross-sectional view of the acoustic device according to the fifth embodiment.

[0056] The substrate 60 is provided on one of the inner wall surfaces 91A, 92A, and 93A, and the main surface of the substrate 60 extends along the inner wall surfaces 91A and 92A of the main wall portions 91 and 92. The sound source 50 is provided on the side of the substrate 60 facing the main wall portion 91. The matching unit 100 is provided on the side wall portion 93. The matching unit 100 is provided on an inner wall surface 93A different from the inner wall surface 91A facing the main surface of the sound source 50. The vibration direction of the sound source 50 is a direction intersecting the inner wall surfaces 91A and 92A of the main wall portions 91 and 92, and the vibration direction of the diaphragm 10 is a direction intersecting the inner wall surface 93A of the side wall portion 93. In other words, the vibration direction of the sound source 50 and the vibration direction of the diaphragm 10 intersect each other, for example, are perpendicular to each other. Even with this arrangement, sound can be sufficiently propagated outside the housing 90.

[0057] Sixth Embodiment Next, the configuration of an acoustic device 6 according to a sixth embodiment will be described with reference to Fig. 9. Fig. 9 is a cross-sectional view of the acoustic device according to the sixth embodiment.

[0058] The matching unit 100 and the sound-producing component 200 are provided on an inner wall surface 91A of a main wall portion 91 of the housing 90. The matching unit 100 and the sound-producing component 200 are lined up along the inner wall surface 91A. The substrate 60 is provided on the inner wall surface 91A of the main wall portion 91, and the sound source 50 is provided on the main wall portion 92 side of the substrate 60. The sound emitted from the sound source 50 does not reach the diaphragm 10 directly, but is reflected at least once by the inner wall surfaces 91A, 92A, and 93A of the housing 90 or the support frame 20 before reaching the diaphragm 10. Even with this arrangement, the sound can be sufficiently propagated outside the housing 90.

[0059] Some or all of the embodiments of the present invention will be described below, but the present invention is not limited to the following descriptions.

[0060] <1> An acoustic device comprising: a matching section provided on an inner wall surface of a housing, the matching section matching acoustic impedance in order to propagate sound from a sound source provided inside the housing to the outside of the housing; the matching section having a support frame provided on the inner wall surface of the housing and a diaphragm supported by the support frame; and the support frame being positioned away from the sound source.

[0061] <2> The acoustic device according to <1>, further comprising a sound source provided inside the housing.

[0062] <3> An acoustic device comprising: a sound source provided inside a housing; and a matching unit provided on an inner wall surface of the housing, the matching unit matching acoustic impedance to propagate sound from the sound source to the outside of the housing, wherein the matching unit has a support frame provided on the inner wall surface of the housing and a vibration membrane supported by the support frame, and the support frame is disposed away from the sound source.

[0063] <4> The acoustic device according to any one of <1> to <3>, wherein the support frame is provided in a cylindrical shape, one end of the support frame is a closed end that is closed by the inner wall surface of the housing, and the other end of the support frame is an open end that is open to the internal space of the housing.

[0064] <5> The acoustic device according to any one of <1> to <4>, wherein the housing seals the internal space.

[0065] <6> The acoustic device according to any one of <1> to <5>, wherein, in a plan view of the inner wall surface on which the support frame is provided, the center of the diaphragm is spaced apart from the center of the sound source.

[0066] <7> The acoustic device according to any one of <1> to <6>, wherein the support frame is arranged adjacent to the sound source with a gap in a direction parallel to an inner wall surface on which the support frame is provided.

[0067] <8> The acoustic device according to any one of <1> to <7>, wherein sound emitted from the sound source is reflected at least once by an inner wall surface of the housing before reaching the diaphragm.

[0068] <9> The acoustic device according to any one of <1> to <8>, wherein the matching section is provided on an inner wall surface of the housing that is different from an inner wall surface that faces a main surface of the sound source.

[0069] <10> An acoustic device comprising: a housing; a sound source provided inside the housing; and a matching unit provided on an inner wall surface of the housing, the matching unit matching acoustic impedance to propagate sound from the sound source to the outside of the housing, the matching unit having a support frame provided on the inner wall surface of the housing and a vibration membrane supported by the support frame, the support frame being disposed away from the sound source.

[0070] As described above, it is possible to provide an acoustic device with improved freedom in design and installation.

[0071] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. The present invention may be modified or improved without departing from its spirit, and equivalents are also included within the scope of the present invention. In other words, designs modified by those skilled in the art as appropriate to the embodiments and / or modifications are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention. For example, the elements and their arrangements, materials, conditions, shapes, sizes, etc. of the embodiments and / or modifications are not limited to those illustrated and can be modified as appropriate. Furthermore, the embodiments and modifications are merely examples, and it goes without saying that partial substitutions or combinations of the components shown in different embodiments and / or modifications are possible. These are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention.

[0072] DESCRIPTION OF SYMBOLS 1 Acoustic device 100 Matching portion 200 Sound-generating component 10 Vibration membrane 20 Support frame 21, 22 End surface 20A Inner surface 20B Outer surface 50 Sound source 60 Substrate 90 Housing 91, 92 Main wall portion 93 Side wall portion 91A, 92A, 93A Inner wall surface 91B, 92B, 93B Outer wall surface

Claims

1. An acoustic device comprising a matching portion provided on the inner wall surface of a housing, the matching portion matching acoustic impedance to propagate sound from a sound source provided inside the housing to the outside of the housing, the matching portion having a support frame provided on the inner wall surface of the housing and a diaphragm supported by the support frame, the support frame being arranged away from the sound source.

2. The acoustic device according to claim 1, further comprising a sound source provided inside the housing.

3. An acoustic device comprising a sound source provided inside a housing and a matching portion provided on the inner wall surface of the housing, the matching portion matching acoustic impedance to propagate sound from the sound source to the outside of the housing, the matching portion having a support frame provided on the inner wall surface of the housing and a diaphragm supported by the support frame, the support frame being arranged away from the sound source.

4. The acoustic device according to any one of claims 1 to 3, wherein the support frame is provided in a cylindrical shape, one end of the support frame is a closed end closed by the inner wall surface of the housing, and the other end of the support frame is an open end open to the internal space of the housing.

5. The acoustic device according to any one of claims 1 to 4, wherein the housing seals the internal space.

6. The acoustic device according to any one of claims 1 to 5, wherein when the inner wall surface on which the support frame is provided is viewed in plan, the central portion of the diaphragm is away from the central portion of the sound source.

7. The acoustic device according to any one of claims 1 to 6, wherein in a direction parallel to the inner wall surface on which the support frame is provided, the support frame is arranged side by side with a space from the sound source.

8. The acoustic device according to any one of claims 1 to 7, wherein the sound emitted from the sound source reaches the diaphragm after being reflected at least once by the inner wall surface of the housing.

9. The acoustic device according to any one of claims 1 to 8, wherein the matching portion is provided on an inner wall surface different from the inner wall surface of the housing facing the main surface of the sound source.

10. An acoustic device comprising a housing, a sound source provided inside the housing, and a matching portion provided on an inner wall surface of the housing for matching acoustic impedance to propagate sound from the sound source to the outside of the housing, the matching portion having a support frame provided on the inner wall surface of the housing and a diaphragm supported by the support frame, the support frame being arranged away from the sound source.

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