Sound absorption glue for surface acoustic wave filter, preparation method of sound absorption glue and surface acoustic wave filter

Abstract

The present invention relates to a surface acoustic wave filter sound absorption adhesive and a preparation method thereof, and a surface acoustic wave filter, the surface acoustic wave filter sound absorption adhesive comprises, by weight, 400-600 parts of polydimethylsiloxane, 40-60 parts of a curing agent and 1 part of silicon oxide nanoparticles, and the silicon oxide nanoparticles and the curing agent are uniformly dispersed in the polydimethylsiloxane. The sound absorption glue for the surface acoustic wave filter has excellent sound absorption performance, good stability and good compatibility.

Description

Technical Field

[0001] The present invention relates to the technical field of surface acoustic wave filters, in particular to a surface acoustic wave filter sound-absorbing adhesive and a preparation method thereof, and a surface acoustic wave filter. Background Art

[0002] Surface acoustic wave (SAW) filters are widely used in communications, radar, and sensor systems. Their core components require extremely high acoustic wave absorption and transmission efficiency. Existing acoustic-absorbing adhesives used in SAW filters suffer from the following drawbacks: 1. Insufficient temperature stability: Traditional materials are prone to deformation or hardening in high or low temperature environments, resulting in unstable device performance. 2. A poor balance between mechanical strength and flexibility: Some materials become more brittle and prone to cracking at low temperatures, while softening at high temperatures, leading to device failure. Summary of the Invention

[0003] In order to solve one or more technical problems existing in the prior art, the present invention provides a surface acoustic wave filter sound-absorbing glue and a preparation method thereof and a surface acoustic wave filter, which are used to improve the acoustic performance and stability of the surface acoustic wave filter at working and storage temperatures.

[0004] The technical solution of the present invention to solve the above technical problems is as follows: the surface acoustic wave filter sound-absorbing adhesive includes, by weight, 400 to 600 parts of polydimethylsiloxane, 40 to 60 parts of a curing agent and 1 part of silicon oxide nanoparticles, wherein the silicon oxide nanoparticles and the curing agent are uniformly dispersed in the polydimethylsiloxane.

[0005] The beneficial effects of the present invention are as follows: the surface acoustic wave filter sound-absorbing adhesive of the present invention has excellent sound absorption performance. The silicon oxide nanoparticles are evenly dispersed in the polydimethylsiloxane matrix, forming a large number of sound scattering and absorption centers, which can effectively absorb the energy of the surface acoustic wave, significantly reduce the fluctuation within the passband of the surface acoustic wave filter, and improve the out-of-band suppression. The surface acoustic wave filter sound-absorbing adhesive of the present invention has good stability. The polydimethylsiloxane itself is stable at the operating and storage temperatures of the surface acoustic wave filter. After the addition of silicon oxide nanoparticles, the stability of the adhesive is not affected, ensuring the long-term reliability of the surface acoustic wave filter. The surface acoustic wave filter sound-absorbing adhesive of the present invention has good compatibility. The silicon oxide nanoparticles have good compatibility with the polydimethylsiloxane. At the same time, the sound-absorbing adhesive also has good bonding properties with the piezoelectric substrate and other components of the surface acoustic wave filter, and can firmly adhere to the surface of the component, reducing interfacial stress, preventing the sound-absorbing adhesive from falling off, and ensuring the normal operation of the filter. By adding a curing agent to the sound-absorbing adhesive, it can be cured on the surface of the surface acoustic wave filter, avoiding flow and affecting the performance of the surface acoustic wave filter.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, based on parts by weight, the composition includes 500 parts of polydimethylsiloxane, 50 parts of a curing agent, and 1 part of silicon oxide nanoparticles.

[0008] The beneficial effect of adopting the above further solution is that the sound absorption effect of the sound-absorbing adhesive can be maximized by reasonably limiting the weight ratio of polydimethylsiloxane and silicon oxide nanoparticles.

[0009] Furthermore, the particle size of the silicon oxide nanoparticles is 20 nm to 80 nm.

[0010] Furthermore, the particle size of the silicon oxide nanoparticles is 40 nm.

[0011] The beneficial effect of adopting the above further solution is that the use of silicon oxide nanoparticles with a particle size of 40 nm can achieve the best sound absorption effect of the sound-absorbing glue.

[0012] The method for preparing a sound-absorbing adhesive for a surface acoustic wave filter comprises the following steps:

[0013] S1, adding silicon oxide nanoparticles to polydimethylsiloxane according to a ratio, and thoroughly mixing using a stirrer to uniformly disperse the silicon oxide nanoparticles in the polydimethylsiloxane to obtain a first mixture;

[0014] S2, adding a curing agent to the first mixture and stirring again to obtain a second mixture;

[0015] S3, pouring the second mixture into a mold, and then placing it in a vacuum environment for degassing to remove bubbles in the second mixture, thereby obtaining the surface acoustic wave filter sound-absorbing adhesive.

[0016] The beneficial effects of the present invention are as follows: the preparation method of the present invention can obtain a uniform and stable sound-absorbing adhesive, which can be applied to surface acoustic wave filters and has a good sound absorption effect. Polydimethylsiloxane (PDMS) as a matrix material has good chemical stability, flexibility and low-temperature characteristics, and can maintain stable physical and chemical properties within the operating and storage temperature range of the surface acoustic wave filter. Silicon oxide nanoparticles have a high specific surface area, good acoustic properties and chemical stability, and are uniformly dispersed in the polydimethylsiloxane (PDMS) matrix, which can effectively improve the absorption capacity of the sound-absorbing adhesive for surface acoustic waves. The prepared sound-absorbing adhesive material has excellent mechanical strength and flexibility, and can extend the service life of the filter.

[0017] Furthermore, in S3, the degassing treatment time is 10 to 20 minutes.

[0018] A surface acoustic wave filter, wherein the portion of the surface acoustic wave filter requiring sound absorption is coated with the surface acoustic wave filter sound-absorbing glue.

[0019] The beneficial effects of the present invention are: the surface acoustic wave filter of the present invention has good sound absorption performance, thereby ensuring the long-term reliability of the surface acoustic wave filter.

[0020] Furthermore, the parts requiring sound absorption are the reflection gratings at the edges of both sides of the surface acoustic wave filter.

[0021] Furthermore, the method for coating the surface acoustic wave filter sound-absorbing glue on the part of the surface acoustic wave filter that needs sound absorption includes the following steps: dipping the surface acoustic wave filter sound-absorbing glue with the tip of a brush, evenly coating it on the part that needs sound absorption, and then placing the surface acoustic wave filter coated with the surface acoustic wave filter sound-absorbing glue in an oven for curing.

[0022] Furthermore, the curing temperature is 70 to 85° C., and the curing time is 1 to 3 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a surface acoustic wave filter coated with sound-absorbing adhesive according to the present invention;

[0024] Figure 2 The performance test curve of the surface acoustic wave filter of the present invention is Figure 1 ;

[0025] Figure 3 The performance test curve of the surface acoustic wave filter of the present invention is Figure 2 ;

[0026] Figure 4 The performance test curve of the surface acoustic wave filter of the present invention is Figure 3 ;

[0027] Figure 5 The performance test curve of the surface acoustic wave filter of the present invention is Figure 4 ;

[0028] Figure 6 The performance test curve of the surface acoustic wave filter of the present invention is Figure 5 ;

[0029] Figure 7 The performance test curve of the surface acoustic wave filter of the present invention is Figure 6 ;

[0030] Figure 8 A comprehensive comparison of the performance test curves of the surface acoustic wave filter of the present invention Figure 1 ;

[0031] Figure 9A comprehensive comparison of the performance test curves of the surface acoustic wave filter of the present invention Figure 2 .

[0032] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0033] 1. Piezoelectric substrate; 2. Interdigital electrodes; 3. Reflection grating; 4. Surface acoustic wave filter sound-absorbing glue. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] Example 1

[0036] The surface acoustic wave filter sound-absorbing adhesive of this embodiment includes, by weight, 500 parts of polydimethylsiloxane, 50 parts of a curing agent, and 1 part of silicon oxide nanoparticles, wherein the silicon oxide nanoparticles are uniformly dispersed in the polydimethylsiloxane.

[0037] In this embodiment, the particle size of the silicon oxide nanoparticles is 20 nm.

[0038] The surface acoustic wave filter sound-absorbing adhesive of this embodiment has excellent sound absorption performance. The silicon oxide nanoparticles are evenly dispersed in the polydimethylsiloxane matrix, forming a large number of sound scattering and absorption centers, which can effectively absorb the energy of the surface acoustic wave, significantly reduce the fluctuation within the passband of the surface acoustic wave filter, and improve the out-of-band suppression. The surface acoustic wave filter sound-absorbing adhesive of this embodiment has good stability. The polydimethylsiloxane itself is stable at the operating and storage temperature of the surface acoustic wave filter. After the addition of silicon oxide nanoparticles, the stability of the adhesive is not affected, ensuring the long-term reliability of the surface acoustic wave filter. The surface acoustic wave filter sound-absorbing adhesive of this embodiment has good compatibility. It utilizes the good compatibility between silicon oxide nanoparticles and polydimethylsiloxane. At the same time, the sound-absorbing adhesive also has good bonding properties with the piezoelectric substrate and other components of the surface acoustic wave filter, and can be firmly attached to the surface of the component, reducing interfacial stress, preventing the sound-absorbing adhesive from falling off, and ensuring the normal operation of the filter.

[0039] The method for preparing the surface acoustic wave filter sound-absorbing adhesive of this embodiment includes the following steps:

[0040] S1, adding silicon oxide nanoparticles to polydimethylsiloxane according to the above ratio, stirring for 10 minutes using a high-speed stirrer to fully mix, so that the silicon oxide nanoparticles are evenly dispersed in the polydimethylsiloxane, to obtain a first mixture;

[0041] S2, adding a curing agent to the first mixture and stirring again to obtain a second mixture;

[0042] S3, pouring the second mixture into a mold, and then placing it in a vacuum environment for degassing treatment. The degassing time is 15 minutes to remove bubbles in the second mixture to ensure the quality and performance of the sound-absorbing adhesive, thereby obtaining the surface acoustic wave filter sound-absorbing adhesive.

[0043] The preparation method of this embodiment can obtain uniform and stable sound-absorbing glue, which can be applied to surface acoustic wave filters and has good sound absorption effect.

[0044] This embodiment also provides a surface acoustic wave filter, wherein the portion of the surface acoustic wave filter that needs to absorb sound is coated with the above-mentioned surface acoustic wave filter sound-absorbing glue. Figure 1 As shown, the surface acoustic wave filter includes a piezoelectric substrate 1, interdigital electrodes 2 and a reflection grating 3. The interdigital electrodes 2 and the reflection grating 3 are on the surface of the piezoelectric substrate 1, and the reflection grating 3 is on both sides of the interdigital electrodes 2. A portion of the reflection grating 3 is coated with a surface acoustic wave filter sound-absorbing glue 4.

[0045] Furthermore, the locations requiring sound absorption are the reflection gratings at the edges of both sides of the surface acoustic wave filter.

[0046] Furthermore, the method of coating the surface acoustic wave filter sound-absorbing glue on the part of the surface acoustic wave filter that needs sound absorption includes dipping the surface acoustic wave filter sound-absorbing glue 4 with the tip of a brush and evenly coating it on the part that needs sound absorption (the reflection grating 3 at the edge positions on both sides of the surface acoustic wave filter), such as Figure 1 As shown, the SAW filter coated with the SAW filter sound-absorbing adhesive 4 is then placed in an oven and cured at 80°C for 2 hours. The adhesive must be applied evenly and burr-free, with no stringing or residual adhesive left in other areas. Subsequently, the adhesive is cured under appropriate temperature and time conditions to form a sound-absorbing adhesive with a certain degree of hardness and elasticity. Curing conditions are optimized based on the type and formulation of PDMS. This creates a good bonding interface between the adhesive and the piezoelectric substrate, effectively absorbing the energy of the SAW waves.

[0047] The surface acoustic wave filter of this embodiment has good sound absorption performance, ensuring the long-term reliability of the surface acoustic wave filter.

[0048] Example 2

[0049] Unlike Example 1, the surface acoustic wave filter sound-absorbing adhesive of this embodiment includes, by weight, 400 parts of polydimethylsiloxane, 40 parts of a curing agent, and 1 part of silicon oxide nanoparticles, wherein the silicon oxide nanoparticles are uniformly dispersed in the polydimethylsiloxane. The remaining steps are the same as in Example 1.

[0050] Example 3

[0051] Unlike Example 1, the surface acoustic wave filter sound-absorbing adhesive of this embodiment includes, by weight, 600 parts of polydimethylsiloxane, 60 parts of a curing agent, and 1 part of silicon oxide nanoparticles, wherein the silicon oxide nanoparticles are uniformly dispersed in the polydimethylsiloxane. The remaining components are the same as in Example 1.

[0052] Example 4

[0053] The difference from Example 1 is that in the method for preparing the sound-absorbing adhesive for the surface acoustic wave filter of this embodiment, the degassing treatment time in S3 is 10 minutes. The rest is the same as Example 1.

[0054] Example 5

[0055] The difference from Example 1 is that in the method for preparing the sound-absorbing adhesive for the surface acoustic wave filter of this embodiment, the degassing treatment time in S3 is 20 minutes. The rest is the same as Example 1.

[0056] Example 6

[0057] Different from Example 1, in this example, the surface acoustic wave filter coated with the surface acoustic wave filter sound-absorbing adhesive is placed in an oven and cured at 70° C. for 3 hours.

[0058] Example 7

[0059] Different from Example 1, in this example, the surface acoustic wave filter coated with the surface acoustic wave filter sound-absorbing adhesive is placed in an oven and cured at 85° C. for 1 hour. The rest is the same as in Example 1.

[0060] Example 8

[0061] The difference from Example 1 is that the particle size of the silicon oxide nanoparticles in this example is 40 nm. The rest is the same as Example 1.

[0062] Example 9

[0063] The difference from Example 1 is that the particle size of the silicon oxide nanoparticles in this example is 60 nm. The rest is the same as Example 1.

[0064] Example 10

[0065] The difference from Example 1 is that the particle size of the silicon oxide nanoparticles in this example is 80 nm. The rest is the same as Example 1.

[0066] The surface acoustic wave filters without sound-absorbing adhesive, the surface acoustic wave filters coated only with polydimethylsiloxane, and the surface acoustic wave filters coated with the corresponding sound-absorbing adhesives in Examples 1, 8, 9, and 10 (the coating amount, coating area, and coating position are all the same) were tested using a vector network analyzer to test their sound absorption performance at different frequencies, the effects of silicon oxide particles of different sizes on the passband fluctuations and out-of-band suppression, and the S21 curves of the surface acoustic wave filters were obtained. The test results are shown in FIG. Figures 2 to 7 As shown. The comprehensive comparison of each test result is as follows: Figure 8 and Figure 9 As shown, the vertical axis is the amplitude (dB) and the horizontal axis is the frequency. Figure 8 and Figure 9 It can be seen that the fluctuation amplitude of the surface acoustic wave filter coated with only polydimethylsiloxane is smaller than that of the surface acoustic wave filter not coated with sound-absorbing glue, and the fluctuation amplitude of the sound-absorbing glue coated with added silicon oxide nanoparticles with a particle size of 20nm is smaller than the fluctuation amplitude of the surface acoustic wave filter coated with only polydimethylsiloxane. It can be found that the device performance has been improved to a certain extent after adding the sound-absorbing glue. After the silicon oxide particles are doped into the polydimethylsiloxane, the passband fluctuation of the device is further reduced. As the particle size of the silicon oxide nanoparticles added in the sound-absorbing glue gradually increases, the fluctuation amplitude first decreases and then increases. When the particle size of the added silicon oxide nanoparticles is 40nm, the passband fluctuation amplitude is the smallest, and the surface acoustic wave filter device performance is the best. This may be because the 40nm particle size of silicon oxide has better dispersion in the polydimethylsiloxane matrix than smaller particles (reduced agglomeration), and the interface density is higher than that of larger particles, forming a uniform microstructure and achieving the best balance between interface area and dispersion.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0068] In the present invention, unless otherwise specified or limited, the terms "adhesion" and "fixation" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; direct connection, indirect connection through an intermediate medium, internal communication between two elements, or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0069] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0070] In the description of this specification, the reference 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 representations 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 features of different embodiments or examples without contradiction.

[0071] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. Surface acoustic wave filter sound-absorbing glue, characterized in that: The invention comprises, by weight, 400 to 600 parts of polydimethylsiloxane, 40 to 60 parts of a curing agent and 1 part of silicon oxide nanoparticles, wherein the silicon oxide nanoparticles and the curing agent are uniformly dispersed in the polydimethylsiloxane.

2. The surface acoustic wave filter sound-absorbing adhesive according to claim 1, characterized in that: In parts by weight, it comprises 500 parts of polydimethylsiloxane, 50 parts of curing agent and 1 part of silicon oxide nanoparticles.

3. The surface acoustic wave filter sound-absorbing adhesive according to claim 1 or 2, characterized in that: The particle size of the silicon oxide nanoparticles is 20 nm to 80 nm.

4. The sound-absorbing adhesive for surface acoustic wave filters according to claim 3, characterized in that: The particle size of the silicon oxide nanoparticles is 40 nm.

5. A method for preparing the sound-absorbing adhesive for surface acoustic wave filters according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, adding silicon oxide nanoparticles to polydimethylsiloxane according to a ratio, and thoroughly mixing using a stirrer to uniformly disperse the silicon oxide nanoparticles in the polydimethylsiloxane to obtain a first mixture; S2, adding a curing agent to the first mixture and stirring again to obtain a second mixture; S3, pouring the second mixture into a mold, and then placing it in a vacuum environment for degassing to remove bubbles in the second mixture, thereby obtaining the surface acoustic wave filter sound-absorbing adhesive.

6. The preparation method according to claim 5, characterized in that: In S3, the degassing treatment time is 10 to 20 minutes.

7. A surface acoustic wave filter, characterized in that The portion of the surface acoustic wave filter that requires sound absorption is coated with the surface acoustic wave filter sound-absorbing adhesive according to any one of claims 1 to 4.

8. The surface acoustic wave filter according to claim 7, wherein: The parts requiring sound absorption are the reflection gratings at the edges of both sides of the surface acoustic wave filter.

9. The surface acoustic wave filter according to claim 7, wherein: The method for coating the surface acoustic wave filter sound-absorbing glue on the part of the surface acoustic wave filter that needs sound absorption comprises the following steps: dipping the surface acoustic wave filter sound-absorbing glue with the tip of a writing brush, evenly coating the glue on the part that needs sound absorption, and then placing the surface acoustic wave filter coated with the sound-absorbing glue in an oven for curing.

10. The surface acoustic wave filter according to claim 9, wherein: The curing temperature is 70-85° C., and the curing time is 1-3 hours.

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