Loudspeaker

Abstract

The present invention relates to the field of electroacoustic conversion, and in particular to a loudspeaker. Compared with the prior art, the loudspeaker of the present invention comprises one or more ultrasonic units connected to each other. Each ultrasonic unit comprises a bottom ultrasonic device and a plurality of displacement assemblies fixed to the bottom ultrasonic device and arranged along the periphery of the bottom ultrasonic device, and the plurality of displacement assemblies and the bottom ultrasonic device together define a sound output channel communicated with the outside. Each displacement assembly comprises a displacement device fixed to the bottom ultrasonic device and a resonant device fixed to the side of the displacement device away from the bottom ultrasonic device, and the resonant device is provided with at least one Helmholtz resonance cavity communicated with the sound output channel. The displacement devices vibrate to drive the resonant devices to resonate, thereby causing a change in the volume of the Helmholtz resonance cavity. An ultrasonic signal emitted by each bottom ultrasonic device is demodulated in the corresponding Helmholtz resonance cavity to form a low-frequency signal, and the low-frequency signal is transmitted to the outside by means of the sound output channel. The loudspeaker has a smaller size and high electroacoustic conversion efficiency.

Description

A loudspeaker TECHNICAL FIELD

[0001] The present application relates to the field of electro-acoustic conversion, and in particular to a loudspeaker. BACKGROUND

[0002] The loudspeaker includes various types, and a directional loudspeaker is a kind of loudspeaker based on the principle of parametric array, which modulates audio signals onto ultrasonic carriers, generates audible sound with high directivity through self-decomposition under the action of nonlinearity. TECHNICAL PROBLEM

[0003] The loudspeaker in the prior art has low electro-acoustic conversion efficiency and large size, the ultrasonic device cannot directly generate audible sound, a specific modulation signal needs to be used, and audible sound is obtained by demodulation using the nonlinearity of ultrasonic propagation in air, and due to the low demodulation efficiency, the loudspeaker has a large module volume and cannot be applied to electronic portable mobile terminals.

[0004] Therefore, it is necessary to provide a new loudspeaker to solve the above technical problems. TECHNICAL SOLUTION

[0005] The present application provides a loudspeaker, which uses a Helmholtz resonant cavity to realize ultrasonic demodulation, has small size and high conversion efficiency.

[0006] In order to achieve the above purpose, the present application provides a loudspeaker, which comprises one or more ultrasonic units connected to each other, the ultrasonic unit comprises a bottom ultrasonic device and a plurality of displacement components fixed to the bottom ultrasonic device and arranged along the periphery of the bottom ultrasonic device, and the plurality of displacement components and the bottom ultrasonic device jointly enclose a sound outlet channel in communication with the outside.

[0007] The displacement component comprises a displacement device fixed to the bottom ultrasonic device and a resonant device fixed to the displacement device away from the bottom ultrasonic device, the resonant device is provided with at least one Helmholtz resonant cavity in communication with the sound outlet channel; the displacement device vibrates to drive the resonant device to resonate, so that the volume of the Helmholtz resonant cavity changes; the ultrasonic signal emitted by the bottom ultrasonic device is demodulated in the Helmholtz resonant cavity to form a low-frequency signal, and the low-frequency signal is transmitted to the outside through the sound outlet channel.

[0008] Preferably, the resonant frequency of the displacement device is the same as the resonant frequency of the air in the Helmholtz resonant cavity.

[0009] Preferably, the resonant frequency of the displacement device is the same as the resonant frequency of the bottom ultrasonic device.

[0010] Preferably, the displacement device is made of piezoelectric material.

[0011] Preferably, the carrier frequency of the ultrasonic signal emitted by the bottom ultrasonic device is greater than or equal to 100 kHz.

[0012] Preferably, the bottom ultrasonic device is rectangular; the displacement assembly includes four and is arranged along the four edges of the bottom ultrasonic device respectively.

[0013] Preferably, three said Helmholtz resonators are arranged on each said displacement device, and the three said Helmholtz resonators are arranged along the sound emission direction of the sound emission channel.

[0014] Preferably, the bottom ultrasonic device includes a device body and a boss formed by extending the device body towards the sound emission channel, and the displacement device is fixed to the boss.

[0015] Preferably, the boss includes a boss body and a groove formed by recessing the boss body away from the sound emission channel, and the displacement device is fixed to the boss body. Advantages

[0016] Compared with the prior art, the loudspeaker of the present application includes one or more ultrasonic units connected with each other, the ultrasonic unit includes a bottom ultrasonic device and a plurality of displacement assemblies fixed to the bottom ultrasonic device and arranged along the periphery of the bottom ultrasonic device, the plurality of displacement assemblies and the bottom ultrasonic device together enclose a sound emission channel in communication with the outside; the displacement assembly includes a displacement device fixed to the bottom ultrasonic device and a resonator fixed to the displacement device away from the bottom ultrasonic device, the resonator is provided with at least one Helmholtz resonator in communication with the sound emission channel; the displacement device vibrates to drive the resonator to resonate, so that the volume of the Helmholtz resonator changes; the ultrasonic signal emitted by the bottom ultrasonic device is demodulated in the Helmholtz resonator to form a low-frequency signal, and the low-frequency signal is transmitted to the outside through the sound emission channel. The loudspeaker is smaller in size and higher in electro-acoustic conversion efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0018] Fig. 1 is a perspective structural schematic view of the loudspeaker provided by the embodiment of the present application;

[0019] Fig. 2 is a schematic view of the ultrasonic unit of the loudspeaker provided by the embodiment of the present application;

[0020] Fig. 3 is a schematic diagram of an ultrasonic unit structure of a loudspeaker according to an embodiment of the present application;

[0021] Fig. 4 is a sectional view along line A-A in Fig. 2. Embodiments of the present application

[0022] The technical solutions in the embodiments of the present application will be apparently and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0023] With reference to Figs. 1 to 3, the present application provides a loudspeaker 100, which comprises one or more ultrasonic units 10 connected to each other. The ultrasonic unit 10 comprises a bottom ultrasonic device 1 and a plurality of displacement assemblies 2 fixed to the bottom ultrasonic device 1 and arranged along the periphery of the bottom ultrasonic device 1. The plurality of displacement assemblies 2 and the bottom ultrasonic device 1 jointly enclose a sound outlet channel 3 in communication with the outside.

[0024] The displacement assembly 2 comprises a displacement device 21 fixed to the bottom ultrasonic device 1 and a resonance device 22 fixed to the displacement device 21 away from the bottom ultrasonic device 1. The resonance device 22 is provided with at least one Helmholtz resonance cavity 23 in communication with the sound outlet channel 3. The displacement device 21 vibrates to drive the resonance device 22 to resonate, so that the volume of the Helmholtz resonance cavity 23 changes. The ultrasonic signal emitted by the bottom ultrasonic device 1 is demodulated in the Helmholtz resonance cavity 23 to form a low-frequency signal, which is transmitted to the outside through the sound outlet channel 3.

[0025] An excitation signal is applied to the displacement device 21 to drive the displacement device 21 to vibrate, thereby harmonically exciting the resonance device 22. The resonance device 22 resonates to produce contraction under the influence of the harmonic force excitation, thereby causing the volume of the Helmholtz resonance cavity 23 to change. The closer the resonance device 22 is to the displacement device 21, the greater the displacement produced.

[0026] Further, due to the volume change of the Helmholtz resonator 23, the air in the Helmholtz resonator 23 also vibrates at the same resonant frequency as the resonant device 22. Therefore, the ultrasonic signal emitted by the bottom ultrasonic device 11 and transmitted to the displacement device 21 is demodulated into a low-frequency signal in the Helmholtz resonator 23, and then transmitted to the outside through the sound outlet channel 3. Specifically, by adjusting the size of the Helmholtz resonator 23, the harmonic change of the sound pressure amplitude of the ultrasonic signal is caused, that is, the sound pressure amplitude is increased or decreased, so as to demodulate the low-frequency information contained in the ultrasonic signal to form the low-frequency signal.

[0027] In the embodiment, the resonant frequency of the displacement device 21 is equal to the resonant frequency of the bottom ultrasonic device 1.

[0028] Specifically, the ultrasonic signal is an ultrasonic modulated signal. Optionally, the ultrasonic signal emitted by the bottom ultrasonic device 1 can be obtained by various modulation methods, such as DSB (Double Sideband Signal) / DSB-SC (Double Sideband with Suppressed Carrier) / SARM / SSB (Single Sideband Signal), etc. The excitation signal driving the displacement device 21 is an ultrasonic single-frequency signal with the same frequency as the ultrasonic signal, and the displacement device 21 is driven to vibrate by the ultrasonic single-frequency signal. As described above, the resonant frequency of the air in the Helmholtz resonator 23 is the same as the resonant frequency of the displacement device 21. According to the modulation and demodulation mechanism of the signal, the ultrasonic modulated signal emitted by the bottom ultrasonic device 1 is multiplied by the ultrasonic single-frequency signal, so as to demodulate the low-frequency information in the ultrasonic signal emitted by the bottom ultrasonic device 1. Finally, the low-frequency signal transmitted to the outside through the sound outlet channel 3 is obtained, and the low-frequency signal can be acquired by the human ear.

[0029] Specifically, the resonant frequency of the air in the Helmholtz resonator 23 can be adjusted according to actual conditions, and the size of the Helmholtz resonator 23 can also be set according to actual requirements, as long as the sound pressure amplitude of the ultrasonic signal emitted by the bottom ultrasonic device 1 can be changed for demodulation. It should be noted that in other embodiments, the resonant frequency of the displacement device 21 does not necessarily need to be equal to the resonant frequency of the bottom ultrasonic device 1, and it can also be similar.

[0030] In the embodiment, the displacement device 21 is made of piezoelectric material. When the displacement device 21 receives an excitation signal, it vibrates along the extension direction of the sound outlet channel 3 to generate displacement, thereby driving the resonator 22 to resonate. It can be understood that in other embodiments, the displacement device 21 can be other devices that can vibrate to generate displacement.

[0031] In the embodiment, the carrier frequency of the ultrasonic signal emitted by the bottom ultrasonic device 1 is greater than or equal to 100 kHz. The bottom ultrasonic device 1 can employ a MEMS ultrasonic device, which can include a diaphragm made of piezoelectric material, which can be the same as the piezoelectric material used to make the displacement device 21.

[0032] The bottom ultrasonic device 1 can be rectangular, circular, or other shapes. As shown in FIG. 2, in the embodiment, the bottom ultrasonic device 1 is rectangular, and the displacement assembly 2 is four, and the four displacement assemblies 2 are arranged along the four edges of the bottom ultrasonic device 1, respectively.

[0033] In the embodiment, each displacement device 21 is provided with three spaced-apart Helmholtz resonators 23, and the three Helmholtz resonators 23 are arranged in the sound outlet direction of the sound outlet channel 3. It should be noted that other numbers of Helmholtz resonators are also possible, which can be set according to actual conditions.

[0034] Specifically, the bottom ultrasonic device 1 includes a device body 11 and a boss 12 extending from the device body 11 to the sound outlet channel 3, and the displacement device 21 is fixed to the boss 12. Specifically, the boss 12 includes a boss body 121 and a groove 122 recessed from the boss body 121 away from the sound outlet channel 33, and the displacement device 21 is fixed to the boss body 121. The groove 122 corresponds to the sound outlet channel 3.

[0035] Compared with the prior art, the loudspeaker of the present application comprises one or more ultrasonic units connected to each other, the ultrasonic unit comprising a bottom ultrasonic device and a plurality of displacement assemblies fixed to the bottom ultrasonic device and arranged along the periphery of the bottom ultrasonic device, the plurality of displacement assemblies and the bottom ultrasonic device together enclosing a sound outlet channel in communication with the outside; the displacement assembly comprising a displacement device fixed to the bottom ultrasonic device and a resonator fixed to the displacement device away from the bottom ultrasonic device, the resonator being provided with at least one Helmholtz resonator in communication with the sound outlet channel; the displacement device vibrates to drive the resonator to resonate, so that the volume of the Helmholtz resonator changes; the ultrasonic signal emitted by the bottom ultrasonic device is demodulated in the Helmholtz resonator to form a low-frequency signal, which is transmitted to the outside through the sound outlet channel. The loudspeaker is smaller in size and higher in electro-acoustic conversion efficiency.

[0036] The above merely describes the embodiments of the present application, and it should be pointed out that those of ordinary skill in the art can make improvements without departing from the inventive concept, and these improvements shall fall within the protection scope of the present application.

Claims

1. A loudspeaker, characterized in that, The loudspeaker includes one or more interconnected ultrasonic units. Each ultrasonic unit includes a bottom ultrasonic device and a plurality of displacement components fixed to the bottom ultrasonic device and arranged along the periphery of the bottom ultrasonic device. The plurality of displacement components and the bottom ultrasonic device together form a sound outlet channel communicating with the outside. The displacement assembly includes a displacement device fixed to the bottom ultrasonic device and a resonant device fixed to the displacement device on the side away from the bottom ultrasonic device. The resonant device is provided with at least one Helmholtz resonant cavity communicating with the sound output channel. The displacement device vibrates to drive the resonant device to resonate, so as to change the volume of the Helmholtz resonant cavity. The ultrasonic signal emitted by the bottom ultrasonic device is demodulated in the Helmholtz resonant cavity to form a low-frequency signal, and the low-frequency signal is transmitted to the outside through the sound output channel.

2. The loudspeaker as claimed in claim 1, characterized in that, The resonant frequency of the displacement device is the same as the resonant frequency of the air inside the Helmholtz resonant cavity.

3. The loudspeaker as claimed in claim 1, characterized in that, The resonant frequency of the displacement device is the same as the resonant frequency of the bottom ultrasonic device.

4. The loudspeaker as claimed in claim 1, characterized in that, The displacement device is made of piezoelectric material.

5. The loudspeaker as claimed in claim 1, characterized in that, The carrier frequency of the ultrasonic signal emitted by the bottom ultrasonic device is greater than or equal to 100kHz.

6. The loudspeaker as claimed in claim 1, characterized in that, The bottom ultrasonic device is rectangular; the displacement assembly includes four components, which are respectively arranged along the four sides of the bottom ultrasonic device.

7. The loudspeaker as claimed in claim 1, characterized in that, Each displacement device is provided with three spaced-apart Helmholtz resonant cavities, and the three Helmholtz resonant cavities are arranged at intervals along the sound output direction of the sound output channel.

8. The loudspeaker as claimed in claim 1, characterized in that, The bottom ultrasonic device includes a device body and a boss extending from the device body toward the sound outlet channel, and the displacement device is fixed to the boss.

9. The loudspeaker as claimed in claim 8, characterized in that, The boss includes a boss body and a groove formed by the boss body recessing in a direction away from the sound outlet channel, and the displacement device is fixed to the boss body.

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