Acoustic device and electronic apparatus

Abstract

The application discloses an acoustic device and an electronic device, and relates to the technical field of acoustics. The acoustic device comprises a shell and a diaphragm, the shell is provided with a sound inlet, the diaphragm is arranged in a containing cavity of the shell, the diaphragm divides the containing cavity into a front cavity and a rear cavity, the front cavity is communicated with the sound inlet, an inner wall of the rear cavity is provided with a sound absorption chamber, the shell is provided with a conductive port, the shell can be electrically connected with the diaphragm, and the diaphragm vibrates under the condition that the conductive port is electrified.

Description

Technical Field

[0001] This application belongs to the field of acoustic technology, specifically relating to an acoustic device and an electronic device. Background Technology

[0002] Noise pollution has become an unavoidable environmental problem in the process of urbanization, including various types such as industrial noise, construction noise, traffic noise, and social noise. However, many noise sources include low-frequency noise, typically ranging from 100-150Hz. Compared to high-pitched high-frequency noise, low-frequency noise has the characteristics of traveling farther and penetrating objects more effectively. Therefore, how to block low-frequency noise has become an important issue.

[0003] Currently, the working principle of ultra-thin acoustic devices mainly involves forming a variable parallel-plate capacitor between a conductive composite film and a perforated metal frame. A bias voltage is then applied to the perforated metal frame, causing the conductive composite film to vibrate under electrostatic force. This vibration, in turn, drives the air to vibrate, thus generating sound. However, while this acoustic device features low power consumption, high energy efficiency, and a thin profile, it cannot achieve low-frequency noise reduction. Summary of the Invention

[0004] The purpose of this application is to provide an acoustic device and electronic device that can solve the problem of large low-frequency noise in current acoustic devices.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application provide an acoustic device, including a housing and a diaphragm. The housing has a sound transmission hole, and the diaphragm is disposed within a receiving cavity of the housing. The diaphragm divides the receiving cavity into a front cavity and a rear cavity. The front cavity is connected to the sound transmission hole, and the inner wall of the rear cavity has a sound-absorbing chamber. The housing has a conductive port, and the housing can be electrically connected to the diaphragm. When the conductive port is energized, the diaphragm vibrates.

[0007] Secondly, embodiments of this application also provide an electronic device, including a circuit board and the aforementioned acoustic device, wherein the circuit board is electrically connected to the conductive port of the acoustic device.

[0008] In this embodiment, the acoustic device includes a housing and a diaphragm. The housing has a sound transmission hole, and the diaphragm is disposed within a cavity of the housing, dividing the cavity into a front cavity and a rear cavity. The front cavity is connected to the sound transmission hole, and the inner wall of the rear cavity has a silencing chamber. The housing has a conductive port, which can be electrically connected to the diaphragm. When the conductive port is energized, a voltage is applied to the housing, causing the diaphragm to be subjected to electrostatic force. At this time, the diaphragm vibrates, thereby driving the air to vibrate and produce sound. The silencing chamber absorbs the sound waves incident on it, thereby reducing or even eliminating reflected sound waves, thus achieving a low-frequency noise reduction effect. Therefore, this embodiment can solve the problem of significant low-frequency noise in current acoustic devices. Attached Figure Description

[0009] Figures 1 to 2 All are exploded views of the acoustic devices disclosed in the embodiments of this application;

[0010] Figure 3 This is a partial cross-sectional view of the first fixing ring disclosed in an embodiment of this application;

[0011] Figure 4 for Figure 3 A magnified view of a portion of the image;

[0012] Figure 5 This is a schematic diagram of the distribution of air particles around the anechoic chamber disclosed in the embodiments of this application;

[0013] Figure 6 This is a schematic diagram of the structure of the noise reduction device and circuit board disclosed in the embodiments of this application.

[0014] Explanation of reference numerals in the attached figures:

[0015] 100-Outer shell, 110-Sound transmission hole, 120-Silence chamber, 121-Narrow tube, 122-Cavity, 123-First silence chamber, 124-Second silence chamber, 130-Conductive port, 131-First conductive port, 132-Second conductive port, 140-First outer shell, 141-First housing, 142-First retaining ring, 150-Second outer shell, 151-Second housing, 152-Second retaining ring, 160-Fastener;

[0016] 200 - Diaphragm, 210 - Supporting film layer, 220 - Conductive film layer;

[0017] 300 - Circuit board, 310 - Rigid body, 320 - Flexible connection part;

[0018] 400-Connector. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] The acoustic devices and electronic devices provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0022] refer to Figures 1 to 6 This application discloses an acoustic device, including a housing 100 and a diaphragm 200. The housing 100 has a sound transmission hole 110. The diaphragm 200 is disposed within a receiving cavity of the housing 100, dividing the receiving cavity into a front cavity and a rear cavity. The front cavity is connected to the sound transmission hole 110 to transmit the sound generated when the diaphragm 200 vibrates. The inner wall of the rear cavity has a sound-absorbing chamber 120. Since the rear cavity mainly affects the low-frequency part of the sound, the sound-absorbing chamber 120 is provided in the rear cavity to absorb low-frequency noise. The housing 100 has a conductive port 130 for electrical connection to an external power source. The housing 100 can be electrically connected to the diaphragm 200. When the conductive port 130 is energized, the housing 100 is electrically connected to the diaphragm 200, and the diaphragm 200 vibrates.

[0023] In this embodiment, when the conductive port 130 is energized, a voltage is applied to the housing 100, causing the diaphragm 200 to be subjected to electrostatic force. The diaphragm 200 vibrates, thereby driving air vibration to produce sound. The anechoic chamber 120 absorbs the sound waves incident upon it, thus reducing or even eliminating reflected sound waves, achieving low-frequency noise reduction. Therefore, this embodiment can solve the problem of significant low-frequency noise in current acoustic devices.

[0024] Optionally, the anechoic chamber 120 can be a cavity with a constant width throughout. In this case, when the sound wave reaches the inner surface of the outer shell 100, a portion enters the cavity and is scattered to dissipate the sound wave energy. However, the cavity needs to be deep enough to fully absorb low-frequency noise of 100 Hz. Based on this, in other embodiments, the anechoic chamber 120 is a Helmholtz resonant cavity. The anechoic chamber 120 includes a connected narrow tube 121 and a cavity 122. The width of the narrow tube 121 is smaller than the width of the cavity 122, and the end of the narrow tube 121 away from the cavity 122 is the opening of the anechoic chamber 120. In this scheme, when the incident sound wave frequency matches the natural frequency within the cavity 122, the air column inside the narrow tube 121 will vibrate violently, thereby generating heat energy through friction with the inner wall of the narrow tube 121. This converts sound energy into mechanical energy, and then into internal energy, thus achieving the purpose of dissipating sound energy.

[0025] Optionally, there may be one anechoic chamber 120; or, there may be at least two anechoic chambers 120, with each anechoic chamber 120 arranged sequentially at intervals along the circumference of the diaphragm 200 to expand the sound absorption range. In this case, the multiple anechoic chambers 120 form a metasurface, thereby converting the incident sound wave into nonradiative mode energy that matches the impedance of the metasurface, thus achieving the effect of absorbing the incident sound wave without generating reflected sound waves.

[0026] In one optional embodiment, the aforementioned at least two anechoic chambers 120 include a first anechoic chamber 123 and a second anechoic chamber 124 arranged adjacent to each other. The width of the narrow tube 121 of the first anechoic chamber 123 is greater than the width of the narrow tube 121 of the second anechoic chamber 124. In this scheme, since the anechoic chamber 120 is a Helmholtz resonator, when the incident sound wave enters the first anechoic chamber 123 and the second anechoic chamber 124 respectively, the two adjacent Helmholtz resonators are excited in an out-of-phase manner. At this time, the velocity field shows that the air particles near the metasurface vibrate parallel to the metasurface. Due to the resonance effect of the Helmholtz resonator, the air pressure amplitude inside the Helmholtz resonator is greater than the incident sound wave pressure. The total energy of the resonant vibration is proportional to the square of the pressure amplitude. Therefore, the strong vibration inside the Helmholtz resonator has a very small loss factor even in air, and can effectively consume energy, thereby achieving the effect of absorbing the incident sound wave without generating reflected sound waves. Of course, the width of the narrow tube 121 of the first anechoic chamber 123 can also be equal to the width of the narrow tube 121 of the second anechoic chamber 124, in which case the structure of each anechoic chamber 120 is the same.

[0027] The first anechoic chamber 123 and the second anechoic chamber 124 are two cavity structures with different resonant frequencies and a phase difference of 180° between them. They are coupled to allow the metasurface to impedance match the sound propagating in the air at a tunable frequency with a subwavelength scale unit. This achieves the effect of completely absorbing the deep subwavelength incident low-frequency sound waves generated by the vibration of the diaphragm 200 without producing reflected sound waves. Specifically, the width and length of the cavity 122 of the coupled first anechoic chamber 123 and the cavity 122 of the second anechoic chamber 124 are equal. The length of the narrow tube 121 of the first anechoic chamber 123 and the narrow tube 121 of the second anechoic chamber 124 are also equal. However, the width of the narrow tube 121 of the first anechoic chamber 123 is different from the width of the narrow tube 121 of the second anechoic chamber 124. That is, the width of the narrow tube 121 of the first anechoic chamber 123 is greater than the width of the narrow tube 121 of the second anechoic chamber 124. When an incident plane wave strikes the metasurface, by rationally designing the width of the narrow tube 121 of the adjacent first anechoic chamber 123 and the width of the narrow tube 121 of the second anechoic chamber 124, a strong response is generated at the resonant frequency between the two, thereby forming a combined resonant mode, which in turn achieves the effect of absorbing the incident sound wave without generating reflected sound waves.

[0028] In a further optional embodiment, the first anechoic chamber 123 and the second anechoic chamber 124 may be irregularly arranged along the circumference of the diaphragm 200, or the first anechoic chamber 123 and the second anechoic chamber 124 may be alternately arranged along the circumference of the diaphragm 200. In the latter embodiment, every two anechoic chambers 120 form a set of out-of-phase resonant cavities (combined resonant mode), that is, the first anechoic chamber 123 and the second anechoic chamber 124, with multiple sets of out-of-phase resonant cavities distributed along the circumference of the diaphragm 200, thereby further improving the noise reduction effect of the acoustic device.

[0029] In one optional embodiment, the outer casing 100 includes a detachably connected first outer casing 140 and a second outer casing 150. The first outer casing 140 includes a first housing 141, and the second outer casing 150 includes a second housing 151. Optionally, both the first housing 141 and the second housing 151 can be metal structures, or they can be non-metal structures; this embodiment does not impose specific limitations on this. Optionally, in the direction perpendicular to the vibration direction of the diaphragm 200, the cross-sectional shape of both the first housing 141 and the second housing 151 can be circular, rectangular, etc.; this is not specifically limited here. The first housing 141 and the second housing 151 form a receiving cavity. The diaphragm 200 is connected to the side wall of the first housing 141 or the side wall of the second housing 151. At this time, the connection area of ​​the diaphragm 200 is small and its stability is poor. The first housing 141 is provided with a sound-absorbing chamber 120. Since the sound-absorbing chamber 120 has a certain depth, the first housing 141 needs to be made thicker. The second housing 151 is provided with a sound transmission hole 110 and a conductive port 130. At this time, the second housing 151 is a conductive structure, and its safety is low. In view of this, optionally, the first housing 140 further includes a first fixing ring 142, which is disposed on the inner surface of the first housing 141 and has a sound-absorbing chamber 120. In this case, the first housing 141 can be made thinner. The second housing 150 further includes a second fixing ring 152, which is disposed on the inner surface of the second housing 151 and has a conductive port 130. In this case, the second housing 151 can be an insulating structure, thereby improving the safety of the entire acoustic device. The diaphragm 200 is connected between the first fixing ring 142 and the second fixing ring 152 to increase the connection area of ​​the diaphragm 200, thereby improving the stability of the diaphragm 200.

[0030] Optionally, the first fixing ring 142 and the second fixing ring 152 may be made of the same or different materials, and this application embodiment does not impose specific limitations on this; further optionally, the first fixing ring 142 and the second fixing ring 152 may both be quartz rings, which have good high temperature resistance and electrical insulation, and of course may also be other structures, and this application embodiment does not impose specific limitations on this.

[0031] Optionally, the first housing 141 and the second housing 151 can be connected by fasteners 160 to facilitate the assembly and disassembly of structures such as the diaphragm 200, the first fixing ring 142 and the second fixing ring 152; further optionally, the fasteners 160 can be screws, bolts, etc., and this application does not impose specific limitations on this.

[0032] The number of fasteners 160 is at least two, and each fastener 160 is arranged at intervals along the circumference of the first housing 141, thereby evenly distributing the force at the edges of the first housing 141 and the second housing 151 to improve the connection between the first housing 141 and the second housing 151.

[0033] Optionally, the second fixing ring 152 may include a ring body and a conductive layer. The conductive layer can be deposited on a local area of ​​the ring body through processes such as spraying or coating to form a conductive port 130, thereby ensuring the strong connection between the second fixing ring 152 and the diaphragm 200. Of course, the conductive layer can also be replaced with a conductive block. In this case, the connection area between the diaphragm 200 and the second fixing ring 152 is smaller, and the connection between the two is not as strong as when a conductive layer is used.

[0034] Alternatively, the conductive layer can be a metal structure layer, which has good conductivity and is beneficial to improving the current transmission efficiency.

[0035] In another embodiment, the number of conductive ports 130 is at least two, including a first conductive port 131 and a second conductive port 132 arranged at intervals. After the first conductive port 131 and the second conductive port 132 are energized, the fixed electrodes at both ends of the diaphragm 200 will generate an electrostatic field in the middle of the electrodes. The electrostatic field will generate an electric field force on the charged diaphragm 200, thereby driving the diaphragm 200 to vibrate.

[0036] Optionally, the inner circumferential surface of the first fixing ring 142 is provided with a silencing chamber 120 so that both the upper and outer circumferential surfaces of the first fixing ring 142 can be connected to the first housing 141, thereby increasing the connection area between the first fixing ring 142 and the first housing 141 and improving the stability of the first fixing ring 142. The lower surface of the first fixing ring 142 can be connected to the diaphragm 200. At this time, the distance between the diaphragm 200 and the silencing chamber 120 is relatively close, which is conducive to the sound waves generated by the vibration of the diaphragm 200 fully entering the silencing chamber 120, thereby improving the silencing effect of the silencing chamber 120. Furthermore, since the silencing chamber 120 is located on the inner circumferential surface of the first fixing ring 142, the thickness of the first fixing ring 142 can be reduced in the direction perpendicular to the diaphragm 200, thereby making the entire acoustic device thinner. Of course, the first fixing ring 142 can also be connected to the first housing 141 only on its outer peripheral surface. In this case, the silencing chamber 120 can be set on the upper surface of the first fixing ring 142. However, the distance between the silencing chamber 120 and the diaphragm 200 is relatively far, and its silencing effect is not as good as that of the silencing chamber 120 set on the inner peripheral surface of the first fixing ring 142.

[0037] In another optional embodiment, the diaphragm 200 includes a stacked support film layer 210 and a conductive film layer 220. The support film layer 210 supports the conductive film layer 220 and also reinforces it, thereby improving the vibration efficiency of the diaphragm 200. The conductive film layer 220 is used to conduct electricity, so that the diaphragm 200 generates an electrostatic field, which generates an electric force that drives the diaphragm 200 to vibrate, thereby causing the air to vibrate and produce sound. The support film layer 210 is connected to the first fixing ring 142, and the conductive film layer 220 is connected to the second fixing ring 152. Optionally, the support film layer 210 and the first fixing ring 142, as well as the conductive film layer 220 and the second fixing ring 152, can be connected by bonding or other means, without specific limitations. The conductive film layer 220 is electrically connected to the conductive port 130 of the second fixing ring 152, and power is supplied to the conductive film layer 220 through the conductive port 130.

[0038] Optionally, the supporting film layer 210 is a polymer film layer, which has good processing performance, toughness, and heat resistance, as well as being lightweight and high-strength. Further optionally, this polymer film layer can be made of materials such as polyimide, polyetherimide, and polyetheretherketone; of course, it can also be made of other polymer materials, without specific limitations. Optionally, the conductive film layer 220 is a graphene film layer, which has good strength, flexibility, electrical and thermal conductivity, and is lightweight. Further optionally, the graphene film layer is a single layer of graphene, which has highly uniform transport characteristics.

[0039] Optionally, only the second housing 151 may be provided with a sound transmission hole 110; or, both the first housing 141 and the second housing 151 may be provided with a sound transmission hole 110, so as to expand the sound transmission range of the acoustic device.

[0040] Optionally, the number of sound transmission holes 110 is at least two, and each sound transmission hole 110 faces the diaphragm 200, thereby improving the sound transmission efficiency of the sound transmission holes 110 and thus improving the acoustic performance of the acoustic device.

[0041] Optionally, the sound transmission hole 110 can be a circular hole, a triangular hole, a rectangular hole, etc., and the embodiments of this application do not impose specific limitations on it; further optionally, the sound transmission hole 110 is a circular hole for ease of setting.

[0042] Based on the acoustic device provided in the embodiments of this application, the embodiments of this application also provide an electronic device, including a circuit board 300 and the acoustic device described in any of the above embodiments. The circuit board 300 is electrically connected to the conductive port 130 of the acoustic device, thereby supplying power to the conductive port 130.

[0043] Optionally, the circuit board 300 includes a rigid body portion 310 and a flexible connection portion 320. The flexible connection portion 320 is electrically connected between the rigid body portion 310 and the conductive port 130, so as to facilitate the flexible connection between the circuit board 300 and the conductive port 130.

[0044] Optionally, the electronic device also includes a connector 400 and a control device. The connector 400 is connected between the circuit board 300 and the control device to facilitate the flexible arrangement of the circuit board 300. The control device is used to control the operation of the circuit board 300.

[0045] The electronic devices disclosed in this application can be smartphones, tablets, e-book readers, wearable devices (such as smartwatches), video game consoles, and other electronic devices. This application does not impose specific limitations on the types of electronic devices.

[0046] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An acoustic device, characterized in that, The device includes a housing (100) and a diaphragm (200). The housing (100) has a sound transmission hole (110). The diaphragm (200) is disposed within a receiving cavity of the housing (100), dividing the receiving cavity into a front cavity and a rear cavity. The front cavity is connected to the sound transmission hole (110). The inner wall of the rear cavity has an anechoic chamber (120). The anechoic chamber (120) includes a narrow tube (121) and a cavity (122) that are connected to each other. The width of the narrow tube (121) is smaller than the width of the cavity (122). The end of the narrow tube (121) away from the cavity (122) is the opening of the anechoic chamber (120). The number of anechoic chambers (120) is at least two, and the at least two anechoic chambers (120) include a first anechoic chamber (123) and a second anechoic chamber (124) arranged adjacent to each other. The width of the narrow tube (121) of the first anechoic chamber (123) is greater than the width of the narrow tube (121) of the second anechoic chamber (124), so that the two are coupled to each other to form a set of out-of-phase resonant cavities. The first anechoic chamber (123) and the second anechoic chamber (124) are alternately arranged along the circumference of the diaphragm (200) to form multiple sets of the out-of-phase resonant cavities; The housing (100) has a conductive port (130) that can be electrically connected to the diaphragm (200). When the conductive port (130) is energized, the diaphragm (200) vibrates.

2. The acoustic device according to claim 1, characterized in that, The anechoic chamber (120) is a Helmholtz resonant cavity.

3. The acoustic device according to claim 2, characterized in that, Each of the anechoic chambers (120) is arranged sequentially at intervals along the circumference of the diaphragm (200).

4. The acoustic device according to claim 1, characterized in that, The outer casing (100) includes a first outer casing (140) and a second outer casing (150) that are detachably connected. The first outer casing (140) includes a first housing (141) and a first fixing ring (142). The first fixing ring (142) is disposed on the inner surface of the first housing (141). The second outer casing (150) includes a second housing (151) and a second fixing ring (152). The second fixing ring (152) is disposed on the inner surface of the second housing (151). The first housing (141) and the second housing (151) form the receiving cavity. The second housing (151) is provided with the sound transmission hole (110). The first fixing ring (142) is provided with the silencing chamber (120). The second fixing ring (152) is provided with the conductive port (130). The diaphragm (200) is connected between the first fixing ring (142) and the second fixing ring (152).

5. The acoustic device according to claim 4, characterized in that, The inner circumferential surface of the first fixing ring (142) is provided with the silencing chamber (120).

6. The acoustic device according to claim 4, characterized in that, The diaphragm (200) includes a stacked support film layer (210) and a conductive film layer (220). The support film layer (210) is connected to the first fixing ring (142), and the conductive film layer (220) is connected to the second fixing ring (152). The support film layer (210) is a polymer film layer, and the conductive film layer (220) is a graphene film layer.

7. The acoustic device according to claim 4, characterized in that, Both the first housing (141) and the second housing (151) are provided with the sound transmission hole (110). The number of the sound transmission holes (110) is at least two, and each of the sound transmission holes (110) faces the diaphragm (200).

8. An electronic device, characterized in that, The device includes a circuit board (300) and an acoustic device according to any one of claims 1 to 7, wherein the circuit board (300) is electrically connected to the conductive port (130) of the acoustic device.

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