Vibrating diaphragm and thermoacoustic film loudspeaker

Abstract

The utility model provides a vibrating diaphragm and a thermoacoustic film loudspeaker, and belongs to the technical field of loudspeakers. The vibrating diaphragm comprises a poly-p-xylylene substrate, a polylysine bonding layer and an MXene surface layer which are sequentially stacked. Compared with a vibrating diaphragm in the prior art, the vibrating diaphragm provided by the utility model is better in sound performance.

Description

Technical Field

[0001] The utility model belongs to the technical field of loudspeakers, and in particular relates to a diaphragm and a thermoacoustic film loudspeaker. Background Art

[0002] Traditional piezoelectric film speakers typically use a thin layer of polyvinylidene fluoride (PVDF) piezoelectric film on a lightweight, porous polyethylene terephthalate (PET) plastic substrate. However, these thin films often lack the necessary thickness, resulting in low volume and poor sound quality.

[0003] A thermoacoustic film speaker generates sound using the thermoacoustic effect of a diaphragm. The principle is that when an alternating current passes through a diaphragm composed of a conductive film, the film generates intermittent Joule heating. Heat exchange between the film and the surrounding medium (such as air) causes the medium's temperature to oscillate, and this thermal expansion and contraction excites sound waves. Thermoacoustic film speakers can be made with micron-nanoscale thicknesses, making them suitable for lightweight speakers in wearable electronics and end devices.

[0004] The diaphragm of current thermoacoustic film speakers typically consists of a nanometer-thick graphene or carbon nanotube conductive film deposited on a substrate. However, due to material and structural limitations, the performance of these thermoacoustic film speakers cannot match that of piezoelectric film speakers. Therefore, it is necessary to design a diaphragm and thermoacoustic film speaker with better acoustic performance. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiment of the present invention provides a diaphragm and a thermoacoustic film loudspeaker.

[0006] An embodiment of the present invention provides a diaphragm, characterized in that it includes a parylene substrate, a polylysine adhesive layer, and a MXene surface layer stacked in sequence.

[0007] The advantages and technical effects brought by the diaphragm of the embodiment of the utility model are:

[0008] (1) The MXenen surface layer has extremely low heat capacity and can be prepared into nano-thin films, which can fully exert the acoustic performance of thin film thermoacoustic speakers.

[0009] (2) There is strong electrostatic interaction and adhesion between the MXene surface layer and the polylysine adhesive layer, which enables the polylysine adhesive layer to maintain a stable surface resistance.

[0010] (3) The polyparaxylene substrate has low thermal permeability and can efficiently radiate heat to the surrounding air while minimizing heat loss from the substrate.

[0011] (4) Compared with the diaphragms in the prior art, the diaphragms of the embodiments of the present invention have good acoustic performance.

[0012] In some embodiments, the parylene substrate has a thickness of 0.1 μm to 50 μm.

[0013] In some embodiments, the parylene substrate has a thickness of 1.5 μm to 2.5 μm.

[0014] In some embodiments, the thickness of the MXene surface layer is 200 nm to 500 nm.

[0015] In some embodiments, the thickness of the MXene surface layer is 250 nm to 350 nm.

[0016] In some embodiments, the total thickness of the diaphragm is 2 μm to 55 μm.

[0017] In some embodiments, the total thickness of the diaphragm is 4 μm to 6 μm.

[0018] In addition, an embodiment of the present invention further provides a thermoacoustic film loudspeaker, comprising the diaphragm described above.

[0019] The advantages and technical effects brought by the thermoacoustic film loudspeaker of the embodiment of the utility model are:

[0020] Compared with the thermoacoustic film loudspeaker in the prior art, the thermoacoustic film loudspeaker in the embodiment of the present invention has good acoustic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the diaphragm of the utility model;

[0022] Figure 2 This is a schematic diagram of an application scenario of the thermoacoustic film loudspeaker of the present invention.

[0023] Description of reference numerals:

[0024] 101-Parylene substrate; 102-Polylysine adhesive layer; 103-MXene surface layer; 1-Thermoacoustic film speaker. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0026] The present invention provides a diaphragm, such as Figure 1As shown, it includes a polyparaxylene substrate 101, a polylysine adhesive layer 102 and a MXene surface layer 103 stacked in sequence.

[0027] The present invention uses MXene film as the surface layer 3 mainly because MXene film (Ti3C2Tx, T is a functional group such as ─OH, ─O or ─F carried on the surface) has an extremely low heat capacity and can be prepared into a nano-scale film, which can fully exert the acoustic performance of the thin film thermoacoustic speaker.

[0028] In addition, the present invention uses a polylysine adhesive layer 102 because the surface functional groups hydroxyl (─OH) and fluorine (─F) of MXene promote strong electrostatic interaction and adhesion between the negatively charged MXene nanosheets and the positively charged amine functional groups of polylysine (zeta potentials of -28.3 mV and +29.6 mV, respectively), allowing the polylysine adhesive layer 102 to maintain a stable surface resistance.

[0029] Furthermore, the low thermal permeability of the parylene substrate 101 is crucial, as it allows for efficient heat radiation to the surrounding air while minimizing heat loss from the substrate.

[0030] The combined effects of these three factors create a periodic thermal radiation pattern when an AC voltage is applied to the highly conductive MXene surface layer 103. This radiation is then conducted into the air via the polylysine adhesive layer 102 and the MXene surface layer 103, generating acoustic radiation due to air pressure oscillations. This generates sound through the thermoacoustic effect. Compared to conventional diaphragms, the diaphragm of this invention offers superior performance.

[0031] In some embodiments, the thickness of the parylene substrate 101 is 0.1 μm to 50 μm, such as 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc. Preferably, the thickness of the parylene substrate 101 is 1.5 μm to 2.5 μm. If the thickness of the parylene substrate 101 is too small, the mechanical strength of the thermal high diaphragm is not improved. If the thickness of the parylene substrate 101 is too large, it is not conducive to reducing heat loss of the substrate.

[0032] In some embodiments, the thickness of the MXene surface layer 103 is 200-500 nm, such as 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, etc. Preferably, the thickness of the MXene surface layer 103 is 250-350 nm. When the thickness of the MXene surface layer 103 is too small, it is not conducive to exerting the thermoacoustic effect. When the thickness of the MXene surface layer 103 is too large, it is not conducive to improving the thermoacoustic efficiency.

[0033] In some embodiments, the total thickness of the diaphragm is 2-55 μm, such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 55 μm, etc. Preferably, the total thickness of the diaphragm is 4-6 μm. When the total thickness of the diaphragm is too small, it is not conducive to exerting the thermoacoustic effect. When the total thickness of the diaphragm is too large, it is not conducive to improving the thermoacoustic efficiency.

[0034] In addition, the utility model embodiment further provides a kind of thermoacoustic diaphragm loudspeaker 1, including the diaphragm described above.

[0035] Since the above-mentioned diaphragm is used, the sound performance of the thermoacoustic diaphragm loudspeaker of the utility model embodiment is good.

[0036] The thermoacoustic diaphragm loudspeaker of the utility model embodiment can be used in wearable electronic products, terminal devices, etc., including but not limited to Figure 2 The ultrathin back shell type loudspeaker shown in the above.

[0037] The utility model will be described in detail below in conjunction with embodiments and drawings.

[0038] Embodiment 1

[0039] A diaphragm includes a parylene substrate 101, a multi-polylysine adhesive layer 102 and a MXene surface layer 103 which are sequentially stacked, the thickness of the parylene substrate 101 is 2 μm, the thickness of the MXene surface layer 103 is 300 nm, and the total thickness of the diaphragm is 5 μm.

[0040] The preparation process of the diaphragm is as follows:

[0041] (1) A layer of sacrificial layer (Micro-90) is coated on a clean glass substrate.

[0042] (2) The parylene substrate 101 with a target thickness is deposited on the sacrificial layer by chemical vapor deposition.

[0043] (3) A poly-lysine (PLL) solution (0.1 w / v% in H2O, Sigma-Aldrich, USA) was spin-coated on the parylene substrate 101 at a speed of 2000 rpm for 60 s to obtain a poly-lysine adhesive layer 102.

[0044] (4) A MXene solution with a concentration of 25 mg / mL was spin-coated on the poly-lysine adhesive layer 102 at a speed of 4000 rpm for 60 s, and annealed at 110° C. for 10 minutes to evaporate the residual solvent, thereby obtaining a MXene surface layer 103 .

[0045] (5) The thin film obtained in step (4) is placed on a silicon wafer, and the sacrificial layer is dissolved in deionized water to obtain a diaphragm.

[0046] Example 2

[0047] This embodiment is the same as embodiment 1, except that the thickness of the parylene substrate 101 is 0.1 μm, the thickness of the MXene surface layer 103 is 200 nm, and the total thickness of the diaphragm is 3.1 μm.

[0048] Example 3

[0049] This embodiment is the same as embodiment 1, except that the thickness of the parylene substrate 101 is 1.5 μm, the thickness of the MXene surface layer 103 is 250 nm, and the total thickness of the diaphragm is 4.5 μm.

[0050] Example 4

[0051] This embodiment is the same as the embodiment 1, except that the thickness of the parylene substrate 101 is 2.5 μm, the thickness of the MXene surface layer 103 is 350 nm, and the total thickness of the diaphragm is 5.5 μm.

[0052] Example 5

[0053] This embodiment is the same as embodiment 1, except that the thickness of the parylene substrate 101 is 50 μm, the thickness of the MXene surface layer 103 is 500 nm, and the total thickness of the diaphragm is 53 μm.

[0054] Objective test of acoustic performance:

[0055] A circular diaphragm with a radius of 2 cm, obtained in Examples 1-5 above, was used as the test sample. Two gold-wire-coated Ni / Cu electrodes were connected and annealed at 70°C for 1.5 hours to produce a thermoacoustic thin-film loudspeaker, ready for use. A signal generator applied an AC voltage of a fixed frequency to the electrodes. Sound pressure levels were measured in an anechoic chamber using a GRAS pistonphone at a point 10 cm from the center of the diaphragm.

[0056] Table 1. Acoustic performance of thermoacoustic film loudspeakers assembled with diaphragms of Examples 1 to 5

[0057] Output frequency / kHz Sound pressure level / dB Example 1 1 75.6 Example 2 1 74.6 Example 3 1 75.9 Example 4 1 75.1 Example 5 1 75.7

[0058] The measurement results of Examples 1 to 5 show that the sound pressure level of the thermoacoustic film loudspeaker can reach 74.6 to 75.9 dB at an output frequency of 1 kHz, indicating that the thermoacoustic film loudspeaker assembled with the diaphragms of Examples 1 to 5 has good acoustic performance.

[0059] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0060] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A diaphragm, characterized in that: It includes a polyparaxylene substrate, a polylysine adhesive layer and a MXene surface layer which are stacked in sequence.

2. The diaphragm according to claim 1, wherein The thickness of the parylene substrate is 0.1 μm to 50 μm.

3. The diaphragm according to claim 2, characterized in that The thickness of the parylene substrate is 1.5 μm to 2.5 μm.

4. The diaphragm according to claim 1, wherein The thickness of the MXene surface layer is 200 nm to 500 nm.

5. The diaphragm according to claim 4, characterized in that The thickness of the MXene surface layer is 250 nm to 350 nm.

6. The diaphragm according to claim 1, wherein: The total thickness of the diaphragm is 2 μm to 55 μm.

7. The diaphragm according to claim 6, characterized in that The total thickness of the diaphragm is 4 μm to 6 μm.

8. A thermoacoustic film loudspeaker, characterized in that: The diaphragm comprises the diaphragm according to any one of claims 1 to 7.

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