Rear cover auxiliary material of electronic equipment, preparation method of rear cover auxiliary material, electronic equipment and rear cover assembly of electronic equipment

Abstract

The invention provides a rear cover auxiliary material of electronic equipment and a preparation method thereof, the electronic equipment and a rear cover assembly of the electronic equipment, and the rear cover auxiliary material of the electronic equipment comprises a zeolite porous layer and a viscoelastic high polymer material barrier layer from inside to outside, the zeolite porous layer comprises a viscoelastic high polymer material matrix and zeolite particles dispersed in the viscoelastic high polymer material matrix, and the zeolite porous layer contains fiber pores. According to the auxiliary material combination for the rear cover of the electronic equipment, the viscoelastic high polymer material and the zeolite particles are used and arranged in the gap between the rear cover of the electronic equipment and the base body of the electronic equipment, a good vibration reduction effect is achieved, shell vibration of the electronic equipment is almost eliminated, and the acoustic low-frequency performance is improved to a certain extent.

Description

Technical Field

[0001] The present invention relates to a back cover auxiliary material of an electronic device and a preparation method thereof, the electronic device and a back cover assembly of the electronic device, belonging to the technical field of terminal equipment. Background Art

[0002] With the development of science and technology, people have higher and higher requirements for speakers, especially mobile phone speakers. The requirements are not only small in size and loud, but also need to provide good sound quality. The quality of sound is related to every aspect of speaker design and manufacturing process, especially the size of the speaker back cavity design. Generally speaking, the reduction of the speaker back cavity will significantly reduce the response of the low frequency band, resulting in poor sound quality, so it is difficult to provide good sound quality under the condition of a very small back cavity.

[0003] To resolve the above contradiction, those skilled in the art have proposed various methods, such as:

[0004] 1. Use gas with better acoustic compliance instead of air as the back cavity atmosphere;

[0005] 2. Fill the rear cavity with foam such as melamine to increase acoustic compliance;

[0006] 3. Filling with porous materials such as activated carbon, zeolite, and silica to increase the volume of the virtual back cavity and improve acoustic compliance;

[0007] 4. Adopt an open speaker design (see CN113364898A for details), which connects the rear cavity of the speaker to the gap in the mobile phone, and uses the slit of the mobile phone as a supplementary rear cavity to further improve the speaker performance, especially the low-frequency performance. However, doing so, on the one hand, puts forward relatively stringent requirements on the sound membrane material; on the other hand, the controllability of the sound field deteriorates significantly; and causes vibration of the mobile phone case. To this end, CN113364898A achieves a shock-absorbing effect by filling a three-layer structure of auxiliary materials (a weak bonding layer, a foam layer, and a strong bonding layer). Although the auxiliary materials filling the three-layer structure can reduce vibration, there is still obvious vibration (the amplitude fluctuation is about 1.5μm).

[0008] Therefore, providing a new type of rear cover auxiliary material and preparation method of an electronic device, an electronic device and a rear cover assembly of the electronic device has become a technical problem that urgently needs to be solved in the art. Summary of the invention

[0009] In order to solve the above-mentioned shortcomings and deficiencies, an object of the present invention is to provide a back cover auxiliary material for an electronic device.

[0010] Another object of the present invention is to provide a method for preparing the rear cover auxiliary material of the above-mentioned electronic device.

[0011] Another object of the present invention is to provide an electronic device, which includes the rear cover auxiliary material of the electronic device mentioned above.

[0012] Another object of the present invention is to provide a back cover assembly of an electronic device, which includes the back cover auxiliary material of the electronic device mentioned above.

[0013] In order to achieve the above objectives, on the one hand, the present invention provides a back cover auxiliary material for an electronic device, wherein the back cover auxiliary material for the electronic device includes two parts from the inside to the outside, a zeolite porous layer (inner layer) and a viscoelastic polymer barrier layer (outer layer), the zeolite porous layer includes a viscoelastic polymer matrix and zeolite particles dispersed in the viscoelastic polymer matrix, and the zeolite porous layer contains fiber pores.

[0014] In the present invention, "inside" and "outside" refer to the direction relative to the back cover of the electronic device, wherein the direction close to the back cover is "outside" and the direction away from the back cover is "inside".

[0015] As a specific embodiment of the back cover auxiliary material of the electronic device described above in the present invention, the diameter of at least one of the fiber holes is 15-50 μm. The fiber holes in the back cover auxiliary material of the electronic device provided by the present invention are formed by pore-forming agents such as soluble PVA fibers. The single fiber hole is similar in size to the soluble PVA fiber, but may be entangled in the structure. After the soluble PVA fiber is dissolved, a fiber hole with a diameter of 15-50 μm and a length of 3-5 mm may be left, or a fiber hole with a diameter and length greater than the aforementioned parameters may be left.

[0016] As a specific embodiment of the back cover auxiliary material of the electronic device described above in the present invention, the zeolite porous layer further comprises a plurality of through holes penetrating therethrough from the inside to the outside, and the plurality of through holes are connected to the fiber holes.

[0017] As a specific embodiment of the back cover auxiliary material of the electronic device mentioned above in the present invention, the particle size of the zeolite particles is 0.1-50 μm.

[0018] As a specific embodiment of the back cover auxiliary material of the electronic device described above in the present invention, the zeolite particles can be zeolite particles with acoustic enhancement commonly used in the art for preparing sound-absorbing particles, including but not limited to one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, MOR structure molecular sieve, FAU structure molecular sieve, BEA molecular sieve and LTA molecular sieve, etc. The zeolite particles used in the present invention can be directly synthesized zeolite raw powder, or they can be formed into micron particles of 5-50μm by molding.

[0019] As a specific embodiment of the back cover auxiliary material of the electronic device described above in the present invention, the viscoelastic polymer material includes various polymer materials with viscoelasticity such as thermoplastic polyurethane elastomer (TPU), thermoplastic polyester elastomer (TPEE), polydimethylsiloxane (PDMS), silicone rubber, polyisobutylene rubber, brominated butyl rubber or polybutadiene rubber, and a mixed polymer material formed by mixing at least two monomers corresponding to the above substances. For example, in a specific embodiment of the present invention, the material of the viscoelastic polymer matrix can be a mixed polymer material after polyisobutylene PIB45000 and brominated butyl rubber 2030 are vulcanized. Among them, the method of mixing at least two monomers to form a mixed polymer material is an existing conventional method.

[0020] In the present invention, the material of the viscoelastic polymer barrier layer can be the same as or different from the material of the viscoelastic polymer matrix. In addition, the silicone rubber, polyisobutylene rubber and polybutadiene rubber can be vulcanized silicone rubber, polyisobutylene rubber and polybutadiene rubber, or unvulcanized silicone rubber, polyisobutylene rubber and polybutadiene rubber.

[0021] As a specific embodiment of the back cover auxiliary material of the electronic device described above in the present invention, the shape of the back cover auxiliary material of the electronic device can be changed according to the cavity of the electronic device, and the thickness is 50-3000 μm.

[0022] In the back cover auxiliary material of the electronic device provided by the present invention, the respective proportions of the zeolite porous layer and the dense viscoelastic polymer material barrier layer can be adjusted, and different parts can be adjusted according to the differences in the installation cavity layout in the electronic device. It is preferred to increase the proportion of the zeolite porous layer on the basis of eliminating shell vibration.

[0023] As a specific embodiment of the back cover auxiliary material of the electronic device described above, the weight ratio of the zeolite porous layer to the viscoelastic polymer material barrier layer is 1:20-20:1, preferably 1:5 to 5:1.

[0024] On the other hand, the present invention also provides a method for preparing the above-mentioned rear cover auxiliary material of the electronic device, wherein the preparation method comprises:

[0025] Step (1): mixing zeolite particles, viscoelastic polymer material or its precursor, pore-forming agent and solvent to obtain a uniform blend slurry;

[0026] Step (2): curing the blended slurry to obtain a porous solid sheet;

[0027] Step (3): post-treating the porous solid sheet to remove residual solvent and pore-forming agent to obtain a zeolite porous layer;

[0028] Step (4): combining the zeolite porous layer and the viscoelastic polymer material barrier layer into one, thereby obtaining the rear cover auxiliary material of the electronic device.

[0029] As a specific embodiment of the preparation method described above in the present invention, the preparation method further comprises: pre-treating the zeolite particles before step (1), wherein the pre-treatment comprises surface modification and / or immersing the zeolite particles in an organic small molecule solvent.

[0030] As a specific embodiment of the preparation method described above of the present invention, the surface modification agent used for the surface modification includes trimethylchlorosilane and / or vinyltrimethoxysilane;

[0031] The organic small molecule solvent includes one or a combination of n-heptane, toluene, xylene, ethylbenzene, gasoline and petroleum ether.

[0032] Among them, the present invention does not make specific requirements for the surface modification and soaking operations and the process parameters involved, and can be reasonably adjusted and selected according to the actual needs of the on-site operation. The surface modification of the zeolite particles in the present invention can make the zeolite particles better mixed with the viscoelastic polymer material, thereby obtaining better acoustic performance; and soaking the zeolite particles in an organic small molecule solvent can make the pores of the zeolite particles (mainly micropores and mesopores, and may also include a small amount of macropores) occupied by organic small molecules in advance, preventing these pores from being blocked by the viscoelastic polymer material when the zeolite particles are mixed with the viscoelastic polymer material, thereby obtaining better acoustic performance.

[0033] As a specific embodiment of the preparation method described above, an auxiliary agent can be added to the blended slurry in step (1) according to the actual on-site operation needs, wherein the present invention does not make specific requirements on the specific substance, addition amount and addition order of the auxiliary agent, and can be reasonably selected and adjusted as needed. For example, in a specific embodiment of the present invention, the auxiliary agent includes n-heptane and a curing agent PDMS B component, and in another specific embodiment of the present invention, the auxiliary agent includes sulfur.

[0034] In step (2) of the preparation method described above, the purpose of curing and shaping is to make the viscoelastic polymer material undergo certain reaction crosslinking or curing, and finally make the blended slurry into an elastic and stable solid form, generally a thin porous form. The present invention does not make specific requirements on the specific operation of curing and shaping and the process parameters used, and the specific curing and shaping method and process parameters can be reasonably selected according to the actual needs of the on-site operation.

[0035] As a specific implementation of the above-mentioned preparation method of the present invention, the preparation method further comprises: drilling holes on the porous solid sheet to form a plurality of through holes.

[0036] As a specific embodiment of the preparation method described above in the present invention, the pore-forming agent includes soluble PVA fibers and the like.

[0037] In step (3) of the preparation method described above, the removal of residual solvent and pore-forming agent not only allows the pores of the zeolite particles to be fully exposed, but also forms a related through-porous structure in a stable solid form, which is convenient for sound waves to enter and exit. The present invention does not make specific requirements on the specific operation of post-treatment and the process parameters used. The specific method of post-treatment and the process parameters can be reasonably selected according to the actual needs of the on-site operation, as long as the purpose of removing the residual solvent and pore-forming agent can be achieved.

[0038] On the other hand, the present invention also provides an electronic device, wherein the electronic device includes a back cover, an electronic device base, an open speaker and the back cover auxiliary material of the electronic device mentioned above, the back cover is used to cover the electronic device base and form an installation cavity therewith, the open speaker and the back cover auxiliary material of the electronic device are both arranged in the installation cavity, and the viscoelastic polymer material barrier layer in the back cover auxiliary material of the electronic device is bonded to the inner layer of the back cover.

[0039] Before placing the back cover auxiliary material of the electronic device in the installation cavity, the back cover auxiliary material of the electronic device is first cut into a corresponding shape according to the specific structure of the installation cavity in the electronic device, and then placed in the installation cavity, and the viscoelastic polymer material barrier layer in the back cover auxiliary material of the electronic device is tightly fitted with the inner layer of the back cover, and the zeolite porous layer in the back cover auxiliary material of the electronic device can contact with the air inside the installation cavity, and can also contact with other hardware inside the installation cavity of the electronic device except the speaker (for example, when the electronic device is a mobile phone, the other hardware includes a circuit board, a battery and a lens module, etc.).

[0040] As a specific embodiment of the electronic device described above in the present invention, the electronic device includes a smart phone, TWS earphones, headphones, smart glasses, smart watches, VR devices, AR devices, tablet computers or thin and light laptops, etc.

[0041] On the other hand, the present invention also provides a back cover assembly of an electronic device, wherein the electronic device includes an electronic device base and an open speaker, wherein the back cover assembly includes a back cover and the back cover auxiliary material of the electronic device described above, the back cover is used to cover the electronic device base and form an installation cavity therewith, the open speaker and the back cover auxiliary material of the electronic device are both arranged in the installation cavity, and the viscoelastic polymer material barrier layer in the back cover auxiliary material of the electronic device is bonded to the inner layer of the back cover.

[0042] Compared with the prior art, the beneficial technical effects that can be achieved by the present invention include:

[0043] The back cover auxiliary material of the electronic device provided by the present invention uses a combination of viscoelastic polymer material and zeolite particles, wherein the zeolite particles themselves have a large number of micropores, which can absorb the energy of sound waves through adsorption and desorption; the viscoelastic polymer material itself also has a significant vibration damping effect, which can dissipate the energy of sound waves. Combining the two, on the one hand, the absorption of sound wave energy can be achieved, and on the other hand, the dissipation of sound wave energy can be achieved, and after the zeolite particles absorb the sound wave energy, the acoustic low frequency f0 can be significantly reduced, thereby obtaining a better acoustic low frequency effect.

[0044] The outer layer of the rear cover auxiliary material of the electronic device provided by the present invention is a viscoelastic polymer barrier layer, which is made of dense viscoelastic polymer material, can increase structural strength and sealing, prevent air and sound leakage, and absorb and eliminate shell vibration to the maximum extent.

[0045] In summary, the back cover auxiliary material of the electronic device provided by the present invention uses a combination of viscoelastic polymer materials and zeolite particles, which are arranged in the gap between the back cover of the electronic device and the electronic device substrate. It not only forms a good vibration reduction effect, almost eliminates the shell vibration of the electronic device, but also improves the acoustic low-frequency performance to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A schematic structural diagram of a rear cover auxiliary material for an electronic device provided by an embodiment of the present invention.

[0048] Figure 2 A schematic diagram of the fitting position of the rear cover auxiliary material of the electronic device provided in an embodiment of the present invention within the installation cavity of a mobile phone.

[0049] Description of main figures:

[0050] 1. MFI zeolite porous layer;

[0051] 11. Viscoelastic polymer material matrix;

[0052] 12. MFI zeolite particles;

[0053] 13. Fiber hole;

[0054] 14. Through hole;

[0055] 2. Viscoelastic polymer barrier layer;

[0056] 100. Auxiliary materials for back covers of electronic equipment;

[0057] 200, back cover;

[0058] 300, open 1115 speakers;

[0059] 400. Battery;

[0060] 500, screen;

[0061] 600. Other parts. DETAILED DESCRIPTION

[0062] It should be noted that the term "comprises" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0063] "Scope" disclosed in the present invention is given in the form of lower limit and upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, for a specific parameter, a range of 60-120 and 80-110 is listed, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4 and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

[0064] In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in the present invention, and "0-5" is just an abbreviation of these numerical combinations.

[0065] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0066] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0067] In the present invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0068] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the attached table, drawings and examples. The following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0069] Example 1

[0070] This embodiment provides a back cover auxiliary material for an electronic device, which is prepared by a preparation method comprising the following specific steps:

[0071] The first step: select MFI zeolite particles (specifically ZSM-5) with a Si / Al molar ratio of 250 and a particle size of 1.5 μm; mix and disperse 10 g of MFI zeolite particles with 50 g of toluene, add 0.2 g of trimethylchlorosilane, stir at 40°C for 4 hours, filter, and disperse and wash with toluene twice to obtain surface-modified MFI zeolite particles.

[0072] Step 2: Accurately weigh 10 parts by weight of the surface-modified MFI zeolite particles obtained in the first step (if containing solvent, calculate based on the dry weight without solvent), 8 parts by weight of polydimethylsiloxane PDMS A component (Dow Corning 184), and 10 parts by weight of n-heptane, stir and mix evenly at room temperature, then add 10 parts by weight of soluble PVA fibers (short fiber diameter is 15-50 μm, length is 3-5 mm), further mix evenly, and then add 0.8 parts by weight of curing agent PDMS B component (Dow Corning 184, B component) to obtain a uniform blended slurry.

[0073] Step 3: Pour the blended slurry into a metal sheet mold, seal it, and heat cure it for 6 hours to obtain a sheet with a thickness of 0.5 mm, and cut it into a rectangle with a width of 80.0 mm and a length of 100.0 mm. Then, drill a through hole with a diameter of 0.3 mm per square millimeter to obtain a porous sheet layer, that is, a porous solid sheet;

[0074] Step 4: Place the porous sheet in 90°C hot water and heat under reflux for 4 hours to dissolve the soluble PVA fibers, thereby obtaining a porous sheet with more complete pores, namely, a zeolite porous layer.

[0075] Step 5: Take a 0.3mm thick PDMS film (pre-cured at 80℃ for 3h), and place the porous sheet obtained in the fourth step flatly on it, apply a pressure of 50N, heat to 120℃ for further curing and cross-linking for 8h, so that the PDMS film and the porous sheet are combined into one to obtain the back cover auxiliary material of the electronic device.

[0076] The structural diagram of the rear cover auxiliary material of the electronic device obtained in this embodiment is as follows Figure 1 As shown, it includes an MFI zeolite porous layer 1 and a viscoelastic polymer barrier layer 2 from the inside to the outside, the MFI zeolite porous layer 1 includes a viscoelastic polymer matrix 11 and MFI zeolite particles 12 dispersed in the viscoelastic polymer matrix 11, the MFI zeolite porous layer 1 includes fiber holes 13 and a plurality of through holes 14 penetrating the MFI zeolite porous layer from the inside to the outside, and the plurality of through holes 14 are connected to the fiber holes 13;

[0077] Among them, the viscoelastic polymer material is PDMS, and the thickness of the back cover auxiliary material of the electronic device is 800μm.

[0078] Example 2

[0079] This embodiment provides a back cover auxiliary material for an electronic device, which is prepared by a preparation method comprising the following specific steps:

[0080] The first step: select MFI zeolite particles (specifically ZSM-5) with a Si / Al molar ratio of 450 and a particle size of 2.5 μm; mix and disperse 1000 g of MFI zeolite particles with 5000 g of toluene, add 20 g of vinyltrimethoxysilane, stir at 40°C for 4 hours, filter, and disperse and wash with toluene twice to obtain surface-modified MFI zeolite particles.

[0081] The second step: accurately weigh 10 parts by weight of the surface-modified MFI zeolite particles obtained in the first step, 12 parts by weight of soluble PVA fibers (short fiber diameter is 15-50 μm, length is 3-5 mm), add 12 parts by weight of polyisobutylene PIB45000, and mix them in an internal mixer for 30 minutes. The internal mixer conditions are: temperature 75°C, speed 50 r / min and filling factor 0.8; then add 0.1 parts by weight of sulfur in an open mixer to obtain a rubber mix; the conditions for vulcanization and sheeting of the rubber mix are: temperature 165°C, time 10 minutes, and the thickness of the vulcanized rubber obtained by sheeting is 0.3 to 1.5 mm.

[0082] Step 3: Take a vulcanized rubber with a thickness of 0.5 mm and cut it into a rectangle with a width of 80.0 mm and a length of 100.0 mm, and then drill a through hole with a diameter of 0.3 mm per square millimeter to obtain a porous sheet layer, that is, a porous solid sheet;

[0083] Step 4: Place the porous sheet in 90°C hot water and heat under reflux for 12 hours to dissolve the soluble PVA fibers, thereby obtaining a porous sheet with more complete pores, namely, a zeolite porous layer.

[0084] Step 5: Take a 0.3mm thick vulcanized polyisobutylene glue (lightly vulcanized to ensure that it has high viscoelasticity in a wide temperature range), and place the porous sheet obtained in the fourth step flatly on it. Press the two at 100°C to combine them into one, and obtain the auxiliary material for the back cover of the electronic device.

[0085] The structural diagram of the rear cover auxiliary material of the electronic device obtained in this embodiment is as follows Figure 1 As shown, it includes an MFI zeolite porous layer 1 and a viscoelastic polymer barrier layer 2 from the inside to the outside, the MFI zeolite porous layer 1 includes a viscoelastic polymer matrix 11 and MFI zeolite particles 12 dispersed in the viscoelastic polymer matrix 11, the MFI zeolite porous layer 1 includes fiber holes 13 and a plurality of through holes 14 penetrating the MFI zeolite porous layer from the inside to the outside, and the plurality of through holes 14 are connected to the fiber holes 13;

[0086] Among them, the viscoelastic polymer material is vulcanized polyisobutylene rubber, and the thickness of the back cover auxiliary material of the electronic device is 800μm.

[0087] Example 3

[0088] This embodiment provides a back cover auxiliary material for an electronic device, and the preparation method thereof is different from that of Embodiment 2 only in that:

[0089] The amount of polyisobutylene PIB45000 in Example 2 was reduced to 10 parts by weight.

[0090] Example 4

[0091] This embodiment provides a back cover auxiliary material for an electronic device, and the preparation method thereof is different from that of Embodiment 2 only in that:

[0092] The amount of polyisobutylene PIB45000 in Example 2 was reduced to 5 parts by weight, and 5 parts by weight of brominated butyl rubber 2030 were additionally added.

[0093] The structural diagram of the rear cover auxiliary material of the electronic device obtained in this embodiment is as follows Figure 1 As shown, it includes an MFI zeolite porous layer 1 and a viscoelastic polymer barrier layer 2 from the inside to the outside, the MFI zeolite porous layer 1 includes a viscoelastic polymer matrix 11 and MFI zeolite particles 12 dispersed in the viscoelastic polymer matrix 11, the MFI zeolite porous layer 1 includes fiber holes 13 and a plurality of through holes 14 penetrating the MFI zeolite porous layer from the inside to the outside, and the plurality of through holes 14 are connected to the fiber holes 13;

[0094] Among them, the material of the viscoelastic polymer barrier layer is vulcanized polyisobutylene rubber, the material of the viscoelastic polymer matrix is ​​a mixed polymer material of polyisobutylene PIB45000 and brominated butyl rubber 2030 vulcanized, and the thickness of the back cover auxiliary material of the electronic device is 800μm.

[0095] Comparative Example 1

[0096] This comparative example provides a back cover auxiliary material for an electronic device, which is a PDMS film with a thickness of 0.8 mm.

[0097] Comparative Example 2

[0098] This comparative example provides a back cover auxiliary material for an electronic device, which is a 0.8 mm thick foam.

[0099] Performance Test Example 1

[0100] This performance test example performs acoustic tests on the rear cover auxiliary materials of the electronic devices provided in Examples 1 to 4 and Comparative Examples 1 and 2 of the present invention, respectively, including:

[0101] Take a commercially available 1115 loudspeaker, remove the sealing film of the leakage port, and enlarge the leakage port to a rectangular opening with a size of 4.0 mm*10.0 mm to form an open 1115 loudspeaker.

[0102] In order to ensure the reliability of mobile phone assembly (to prevent repeated removal of the back cover of the mobile phone and the difference in sealant adhesion), the structural diagram is selected as follows Figure 2 The mobile phone mold shown is evaluated as a mobile phone tooling: the mobile phone tooling weighs 200g, and its dimensions are 17mm long*85mm wide*9mm thick. There are structures and screws for fixing the speaker inside to fix the open 1115 speaker mentioned above; the gap between the back cover and the body is 0.5-1.0mm (the narrowest part is 0.5mm, and the widest part is 1.0mm). According to the internal gap of the mobile phone, the excess parts of the back cover auxiliary materials of the electronic equipment provided in Examples 1 to 4 of the present invention and Comparative Examples 1 and 2 are cut off respectively, so that the back cover auxiliary materials are closely fitted to the back cover of the mobile phone, as shown in FIG. Figure 2 As shown, from Figure 2 It can be seen that the mobile phone tooling includes a body, a rear cover auxiliary material 100 of an electronic device, a rear cover 200, an open 1115 speaker 300, a battery 400, a screen 500 and other components 600. The rear cover 200 is used to cover the body and form an installation cavity with it. The open 1115 speaker 300, the battery 400, other components 600 and the rear cover auxiliary material 100 of the electronic device are all arranged in the installation cavity, and the viscoelastic polymer material barrier layer in the rear cover auxiliary material 100 of the electronic device is tightly attached to the inner layer of the rear cover 200, and the zeolite porous layer is in contact with the air inside the installation cavity;

[0103] The open-type 1115 speaker is matched with the back cover and fixed to the body by screws, and there are sealing rings around the body and the back cover for sealing.

[0104] The acoustic performance tests were conducted using conventional methods in the art on commercially available 1115 speaker units, 1115 speakers with added rear cavities, open-type 1115 speakers, mobile phone tooling equipped with open-type 1115 speakers and the back cover auxiliary materials of the electronic devices provided in Examples 1 to 4 and Comparative Examples 1 to 2 of the present invention, and a mobile phone tooling (blank) equipped with only an open-type 1115 speaker. The obtained f0 data are shown in Table 1 below.

[0105] Performance Test Example 2

[0106] This performance test example uses an amplitude measuring instrument (piezoelectric acceleration sensor) to perform amplitude tests on the mobile phone tooling obtained in performance test example 1, which is respectively equipped with an open 1115 speaker and the rear cover auxiliary materials of the electronic device provided by Examples 1 to 4 of the present invention and Comparative Examples 1 to 2, and the mobile phone tooling (blank) only equipped with an open 1115 speaker, including:

[0107] Use tape to tightly bond the bottom of the vibration sensor, i.e. the piezoelectric acceleration sensor, to the back cover of the mobile phone tooling; then place it on the sponge to prevent direct hard contact with the desktop from affecting the test results; there are two options for test signal input: one is to use the pink noise test signal of CF 2.2, and the pink noise voltage is 1.65V; the other is to directly use the test mobile phone, i.e. the mobile phone tooling to play, and adjust the volume of the test mobile phone to the maximum for testing;

[0108] Play the pink noise test signal in a loop and start the test using an amplitude meter. Do not read the test value for the first 3 seconds, then continue for 20 seconds. Read the maximum value of the test data within 20 seconds and record it as the value of the test point.

[0109] Change the fixed position of the back cover of the mobile phone mold and the vibration sensor, retest the next fixed position, and record the value of the test point; in this performance test example, the back cover of the mobile phone mold is divided into 9 grids, and the vibration amplitude of 9 points is measured; the maximum vibration distance range is recorded, as shown in Table 1 below.

[0110] Performance Test Example 3

[0111] This performance test example uses an amplitude measuring instrument (piezoelectric acceleration sensor) to perform a tactile test on the mobile phone tooling obtained in performance test example 1, which is equipped with an open 1115 speaker and the rear cover auxiliary materials of the electronic device provided by Examples 1 to 4 of the present invention and Comparative Examples 1 to 2, and the mobile phone tooling (blank) only equipped with an open 1115 speaker, including:

[0112] The mobile phone tooling was placed in the hands of ten testers, and then a pink noise test signal of CF 2.2 was given to the speaker. The testers made a qualitative evaluation based on their subjective touch. The evaluation results are shown in Table 1 below.

[0113] Table 1

[0114]

[0115]

[0116] It can be seen from Table 1 above that the f0 of the 1115 speaker unit itself is around 440Hz. After adding the back cavity, the f0 of the 1115 speaker increases to around 860Hz. After opening the leakage port of the 1115 speaker and drilling a larger leakage hole, its f0 is measured to be reduced to around 530Hz in an open environment.

[0117] The blank mobile phone tooling corresponds to a mobile phone tooling with only an open 1115 speaker installed. Its f0 is measured to be around 640Hz in a closed environment.

[0118] Compared with a blank mobile phone tooling, the mobile phone tooling to which the back cover auxiliary materials of the electronic device provided by Examples 1 to 4 of the present invention and the open 1115 speakers are respectively installed, not only the vibration of the mobile phone is greatly reduced, but also the acoustic f0 is significantly reduced. The reduction in f0 indicates that these mobile phone toolings have better low-frequency effects.

[0119] Compared with the blank mobile phone tooling, the vibration of the mobile phone tooling equipped with the back cover auxiliary material of the electronic device provided in Comparative Example 1 and the open 1115 speaker is also greatly reduced, but its acoustic f0 is significantly increased compared with the blank mobile phone tooling and the mobile phone tooling equipped with the back cover auxiliary material of the electronic device provided in Example 1 of the present invention and the open 1115 speaker. This is because the thickness of the PDMS film used as the back cover auxiliary material of the electronic device in Comparative Example 1 reaches 0.8 mm, which is equivalent to the thickness of the viscoelastic polymer barrier layer reaching 0.8 mm. The viscoelastic polymer barrier layer occupies a large amount of mobile phone gaps, causing the actual cavity volume to become smaller, thereby resulting in a significant increase in the acoustic f0; in addition, compared with Comparative Example 1, the back cover auxiliary material of the electronic device provided in Example 1 of the present invention also includes MFI zeolite particles, wherein the MFI zeolite particles themselves have a large number of micropores, which can absorb the sound wave energy through adsorption and desorption, thereby significantly reducing the acoustic low-frequency f0, thereby obtaining a better acoustic low-frequency effect.

[0120] Compared with the mobile phone tooling equipped with the back cover auxiliary materials of the electronic device provided in Examples 1 to 4 of the present invention and the open 1115 speakers, although the acoustic f0 of the mobile phone tooling equipped with 0.8 mm thick foam and the open 1115 speakers does not deteriorate significantly, its vibration reduction effect is extremely limited.

[0121] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other and with each other, and with each other.

Claims

1. A back cover auxiliary material for an electronic device, characterized in that: The rear cover auxiliary material of the electronic device includes a zeolite porous layer and a viscoelastic polymer barrier layer from the inside to the outside. The zeolite porous layer includes a viscoelastic polymer matrix and zeolite particles dispersed in the viscoelastic polymer matrix. The zeolite porous layer contains fiber pores.

2. The rear cover auxiliary material of the electronic device according to claim 1, characterized in that: The diameter of at least one of the fiber holes is 15-50 μm.

3. The rear cover auxiliary material of the electronic device according to claim 1, characterized in that: The zeolite porous layer further comprises a plurality of through holes penetrating therethrough from the inside to the outside, and the plurality of through holes are connected to the fiber holes.

4. The rear cover auxiliary material of the electronic device according to claim 1, characterized in that: The particle size of the zeolite particles is 0.1-50 μm.

5. The rear cover auxiliary material of an electronic device according to any one of claims 1 to 4, characterized in that: The zeolite particles include one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, MOR structure molecular sieve, FAU structure molecular sieve, BEA molecular sieve and LTA molecular sieve.

6. The rear cover auxiliary material of an electronic device according to any one of claims 1 to 4, characterized in that: The viscoelastic polymer material includes thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, polydimethylsiloxane, silicone rubber, polyisobutylene rubber, brominated butyl rubber or polybutadiene rubber, and a mixed polymer material formed by mixing at least two monomers corresponding to the above substances.

7. The rear cover auxiliary material of an electronic device according to any one of claims 1 to 4, characterized in that: The thickness of the rear cover auxiliary material of the electronic device is 50-3000 μm.

8. The rear cover auxiliary material of an electronic device according to any one of claims 1 to 4, characterized in that: The weight ratio of the zeolite porous layer to the viscoelastic polymer material barrier layer is 1:20-20:1, preferably 1:5 to 5:

1.

9. The method for preparing the auxiliary material for the back cover of an electronic device according to any one of claims 1 to 8, characterized in that: The preparation method comprises: Step (1): mixing zeolite particles, viscoelastic polymer material or its precursor, pore-forming agent and solvent to obtain a uniform blend slurry; Step (2): curing the blended slurry to obtain a porous solid sheet; Step (3): post-treating the porous solid sheet to remove residual solvent and pore-forming agent to obtain a zeolite porous layer; Step (4): combining the zeolite porous layer and the viscoelastic polymer material barrier layer into one, thereby obtaining the rear cover auxiliary material of the electronic device.

10. The preparation method according to claim 9, characterized in that: The preparation method further comprises: performing pretreatment on the zeolite particles before step (1), wherein the pretreatment comprises surface modification and / or immersing the zeolite particles in an organic small molecule solvent.

11. The preparation method according to claim 10, characterized in that: The surface modification agent used in the surface modification includes trimethylchlorosilane and / or vinyltrimethoxysilane; The organic small molecule solvent includes one or a combination of n-heptane, toluene, xylene, ethylbenzene, gasoline and petroleum ether.

12. The preparation method according to claim 9, characterized in that: The preparation method further comprises: drilling holes on the porous solid sheet to form a plurality of through holes.

13. The preparation method according to any one of claims 9 to 12, characterized in that: The pore former includes soluble PVA fibers.

14. An electronic device, characterized in that: The electronic device comprises a back cover, an electronic device base, an open speaker and the back cover auxiliary material of the electronic device as described in any one of claims 1-8, the back cover is used to cover the electronic device base and form an installation cavity therewith, the open speaker and the back cover auxiliary material of the electronic device are both arranged in the installation cavity, and the viscoelastic polymer material barrier layer in the back cover auxiliary material of the electronic device is bonded to the inner layer of the back cover.

15. The electronic device according to claim 14, characterized in that: The electronic device includes a smart phone, a TWS headset, a head-mounted headset, smart glasses, a smart watch, a VR device, an AR device, a tablet computer or a thin and light laptop computer.

16. A back cover assembly of an electronic device, the electronic device comprising an electronic device base and an open speaker, characterized in that: The back cover assembly includes a back cover and the back cover auxiliary material of the electronic device as described in any one of claims 1-8, the back cover is used to cover the electronic device base and form an installation cavity therewith, the open speaker and the back cover auxiliary material of the electronic device are both arranged in the installation cavity, and the viscoelastic polymer material barrier layer in the back cover auxiliary material of the electronic device is bonded to the inner layer of the back cover.

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