Electromagnetic shielding-free pure polymer ultrathin flexible vapor chamber and preparation method thereof

Abstract

The invention relates to a pure polymer ultrathin flexible vapor chamber without electromagnetic shielding and a preparation method thereof in the technical field of vapor chamber heat dissipation. The pure polymer ultrathin flexible vapor chamber comprises a first substrate; the plurality of unit bodies are arranged on one side of the first substrate in an array manner to form an array structure; the side, provided with the array structure, of the first substrate is covered with the second substrate, and a sealed cavity is formed by the second substrate, the first substrate and the array structure; partial space of the cavity is filled with the working medium; the first substrate and the second substrate are made of polymers, and the unit bodies are made of resin. According to the pure polymer ultrathin flexible vapor chamber without electromagnetic shielding and the preparation method thereof, the heat dissipation efficiency can be effectively improved, the temperature of equipment is reduced, electromagnetic shielding is avoided, and the performance and reliability of the equipment are remarkably enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of heat dissipation and particularly to a pure polymer ultra-thin flexible heat spreader without electromagnetic shielding and a preparation method thereof. Background Art

[0002] In recent years, the performance of the core components of electronic devices has been significantly improved. At the same time, the trend of miniaturization and thinness of equipment has become increasingly obvious, resulting in a sharp reduction in heat dissipation space and a significant increase in heat flux density, which in turn exacerbates the heat dissipation problem of electronic devices. Ultra-thin phase change heat dissipation technology has become an ideal solution to this challenge due to its efficient heat dissipation performance and has been widely used in thin and light electronic devices.

[0003] However, with the rapid development and popularization of foldable and flexible screen technologies, wearable electronic devices such as foldable mobile phones, curved bracelets, and head-mounted virtual reality (VR) devices have become the new favorites of the market, indicating that microelectronic devices are developing in a direction of being lighter, thinner, and more flexible. This not only requires electronic devices to be miniaturized and thinner in heat dissipation design, but also puts forward new requirements for the flexibility of heat dissipation materials.

[0004] Ultra-thin flexible vapor chambers can effectively solve heat dissipation problems in electronic products and improve product performance and stability. However, the heat sinks on the market currently mainly use metal materials as substrates, which may shield or interfere with the device's signals, especially in devices such as 5G base stations and FTTR optical modems that have extremely high requirements for signal quality. This effect may significantly reduce the overall performance of the device. Summary of the invention

[0005] In view of the problems existing in the background technology, the present application provides a pure polymer ultra-thin flexible heat sink without electromagnetic shielding and a preparation method thereof, which can effectively improve the heat dissipation efficiency, reduce the temperature of the equipment, and avoid electromagnetic shielding, thereby significantly enhancing the performance and reliability of the equipment.

[0006] According to one aspect of the present invention, there is provided a pure polymer ultra-thin flexible heat spreader without electromagnetic shielding, comprising: a first substrate; a plurality of unit bodies, wherein the plurality of unit bodies are arranged in an array on one side of the first substrate to form an array structure; a second substrate, wherein the second substrate covers the side of the first substrate with the array structure, and the second substrate forms a sealed cavity with the first substrate and the array structure; a working fluid, wherein the working fluid fills part of the space of the cavity; the material of the first substrate and the second substrate is selected from polymers, and the material of the unit bodies is selected from resins.

[0007] In some embodiments of the present invention, the polymer is selected from one or more of polyimide, polyethylene terephthalate, polyphenylene sulfide and polyurethane.

[0008] In some embodiments of the present invention, the thickness of the first substrate and the second substrate are independently 0.025 mm-0.075 mm.

[0009] In some embodiments of the present invention, the first substrate and / or the second substrate is made of transparent material.

[0010] In some embodiments of the present invention, the resin is doped with a substance having a hydrophilic group.

[0011] In some embodiments of the present invention, the substance is selected from one or more of a surfactant, a hydrophilic polymer, an aqueous additive, a hydrophilic nanomaterial and a modifier.

[0012] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned pure polymer ultra-thin flexible heat spreader without electromagnetic shielding, which is characterized in that it comprises the following steps: preparing a first substrate and a second substrate; performing integrated 3D printing on the first substrate to prepare a unit body and form an array structure; cutting and bonding the packaging edge of the first substrate, placing an injection tube and a sealing material at the tail thereof; using a heat sealer to perform hot-pressing sealing on the first substrate and the second substrate at the bonding edge; performing precise liquid injection, primary degassing, and secondary degassing on the sealed first and second substrates; heating and pressurizing the sealing material using a heat sealer, and cutting off the injection tube portion.

[0013] In some embodiments of the present invention, the sealing temperature of the heat sealer is 150° C.-290° C., and the pressure is 0.6 MPa-0.8 MPa.

[0014] In some embodiments of the present invention, the first substrate and the second substrate after injection are placed in a low-temperature environment so that the working medium is at a low temperature, and then degassing is performed.

[0015] In some embodiments of the present invention, after the secondary degassing, the pressure of the cavity is less than 100 Pa.

[0016] Compared with the prior art, the present invention achieves the following technical effects:

[0017] 1. The present invention uses a polymer film with excellent flexibility, such as a polyimide film, a polyethylene terephthalate film, a polyphenylene sulfide film or a polyurethane film as the first substrate and the second substrate of the ultra-thin flexible heat spreader. Compared with conventional metal or graphene substrates, it does not cause interference during the signal transmission process of the electronic device, significantly enhances the performance and reliability of the electronic device, and has the advantages of light weight and low cost.

[0018] 2. The present invention successfully manufactures a pure polymer ultra-thin flexible heat spreader through micro-scale 3D printing technology. The heat spreader is not only suitable for the heat dissipation needs of flexible electronic devices, but also can meet the use of various devices that require uniform heat dissipation.

[0019] 3. The pure polymer ultra-thin flexible heat spreader of the present invention can improve the efficiency of heat conduction, effectively reduce thermal resistance, avoid electromagnetic shielding, reduce energy consumption, and further help reduce the power consumption of the device during operation, thereby extending the battery life of the device and improving the overall performance and user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0021] Figure 1 It is a schematic diagram of the overall structure of the pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding of the present invention;

[0022] Figure 2 It is a schematic diagram of the assembly of the pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding of the present invention;

[0023] Figure 3 Schematic diagram of the array structure of the pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding of the present invention;

[0024] Figure 4 Schematic diagram of bending of the pure polymer ultra-thin flexible heat spreader without electromagnetic shielding of the present invention;

[0025] Figure 5 The present invention is a process flow chart for preparing a pure polymer ultra-thin flexible heat spreader without electromagnetic shielding.

[0026] The reference numerals in the accompanying drawings represent the following: 1. first substrate; 2. array structure; 3. second substrate; 4. liquid injection tube; 5. cavity. DETAILED DESCRIPTION

[0027] It should be clear that 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 ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0028] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0029] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0030] Ultra-thin flexible heat spreaders can effectively solve heat dissipation problems in electronic products and improve product performance and stability. However, current radiators mainly use metal materials as the substrate, which may shield or interfere with the device's signal. Especially in devices such as 5G base stations and FTTR photoelectric modems that have extremely high requirements for signal quality, this impact may significantly reduce the overall performance of the device.

[0031] Based on this, the present invention proposes a pure polymer ultra-thin flexible heat spreader without electromagnetic shielding and a preparation method thereof, using a first substrate and a second substrate made of pure polymer material, and an array structure formed by a unit body of resin material as a liquid absorbent core, and the liquid absorbent core also serves as a supporting column, which can not only effectively improve the heat dissipation efficiency and reduce the temperature of the equipment, but also avoid the generation of electromagnetic shielding, significantly enhancing the performance and reliability of the equipment.

[0032] The present application discloses a pure polymer ultra-thin flexible heat spreader without electromagnetic shielding. Figure 1-4 As shown, the pure polymer ultra-thin flexible heat spreader without electromagnetic shielding includes a first substrate 1, a plurality of unit bodies, a second substrate 3 and a working medium.

[0033] Wherein, a plurality of unit cells are arrayed on one side of the first substrate 1 to form an array structure 2;

[0034] The second substrate 3 covers the side of the first substrate 1 with the array structure 2 . The second substrate 3 , the first substrate 1 and the array structure 2 form a sealed cavity 5 , and the working fluid fills part of the space of the cavity 5 .

[0035] The materials of the first substrate 1 and the second substrate 3 are selected from polymers, and the material of the unit body is selected from resins.

[0036] By using the pure polymer ultra-thin flexible heat spreader without electromagnetic shielding in the technical solution, using the first substrate 1 and the second substrate 3 made of pure polymer material, and cooperating with the array structure 2 formed by the unit body of resin material as the liquid absorption core and the support column, without using any metal substrate, the generation of electromagnetic shielding is completely avoided, thereby significantly enhancing the performance and reliability of the equipment. Moreover, the array structure 2 is formed by the unit body of resin material, and the cavity 5 between the first substrate 1 and the second substrate 3 of the array structure 2 is arranged as the liquid absorption core and the support column, which can effectively improve the heat dissipation efficiency and reduce the temperature of the equipment, and can also ensure the structural strength and flexibility of the ultra-thin flexible heat spreader.

[0037] Avoiding electromagnetic shielding helps to reduce device power consumption and enhance device endurance without reducing user signal strength, thus providing users with a more efficient and lasting user experience. At the same time, the ultra-thin flexible heat spreader can be customized according to the specific shape and space requirements of the device. Its compact design does not take up extra space, which is conducive to optimizing product design and maximizing space utilization. Compared with traditional heat spreaders, the pure polymer ultra-thin flexible heat spreader of the present invention is lighter and thinner, which helps to reduce the overall weight of the device. It is suitable for electronic equipment, communication systems, aerospace and other fields, and can be widely used in various innovative fields, especially wearable devices and flexible displays, showing extraordinary adaptability and flexibility.

[0038] In some embodiments of the present invention, the polymer is selected from one or more of polyimide (PI), polyethylene terephthalate (PET), polyphenylene sulfide (PPS) and polyurethane (PU).

[0039] It should be understood that when the polymer is selected from one of polyimide, polyethylene terephthalate, polyphenylene sulfide and polyurethane, the first substrate 1 and the second substrate 3 can be independently polyimide film, polyethylene terephthalate film, polyphenylene sulfide film or polyurethane film.

[0040] Furthermore, when the polymer is a combination of multiple types of polyimide, polyethylene terephthalate, polyphenylene sulfide and polyurethane, the first substrate 1 and the second substrate 3 can be independent films of the corresponding compositions.

[0041] Polymers such as polyimide, polyethylene terephthalate, polyphenylene sulfide and polyurethane have excellent flexibility and good thermal conductivity, which can make ultra-thin flexible heat sinks better used in electronic products such as folding mobile phones, curved bracelets and head-mounted virtual reality devices and improve heat dissipation efficiency.

[0042] In some embodiments of the present invention, the thickness of the first substrate 1 and the second substrate 3 are independently 0.025 mm-0.075 mm.

[0043] The thickness of the first substrate 1 and the second substrate 3 is not particularly limited. Those skilled in the art can make reasonable choices based on actual needs. As some specific examples, the thickness of the first substrate 1 or the second substrate 3 can be 0.025 mm, 0.030 mm, 0.035 mm, 0.040 mm, 0.045 mm, 0.050 mm, 0.055 mm, 0.060 mm, 0.065 mm, 0.070 mm, 0.075 mm, etc.

[0044] In some embodiments of the present invention, the first substrate 1 and / or the second substrate 3 is made of transparent material.

[0045] It is worth mentioning that some pure polymer materials exhibit transparent and visual properties, and the ultra-thin flexible heat sinks made from them are also unique in visual aesthetics, which can bring an unprecedented perfect fusion of art and technology to product design, allowing it to show significant advantages while pursuing aesthetics and functionality, significantly improving the product's appearance appeal.

[0046] In some embodiments of the present invention, the resin is doped with a substance having a hydrophilic group.

[0047] Substances with hydrophilic groups can significantly improve the hydrophilicity of the array structure 2 (unit body), so that the array structure 2 has excellent water transmission ability, further improving the heat dissipation efficiency and heat dissipation effect of the ultra-thin flexible heat sink, and further enhancing the ability to control the temperature of the equipment. The pure polymer ultra-thin flexible heat sink of the present invention, as a new type of radiator, not only exhibits excellent thermal conductivity, but also meets the strict requirements of heat dissipation equipment for flexibility, effectively solves the electromagnetic signal shielding problem that may be caused by traditional metal radiators, and better realizes the dual optimization of heat dissipation and signal transmission.

[0048] In some embodiments of the present invention, the substance is selected from one or more of a surfactant, a hydrophilic polymer, an aqueous additive, a hydrophilic nanomaterial, and a modifier.

[0049] For example, the surfactant can be selected from emulsifiers, including but not limited to non-ionic emulsifiers (such as polyoxyethylene ethers, nonylphenol polyoxyethylene ethers, etc.), anionic emulsifiers (such as sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, etc.) or cationic emulsifiers (such as hexadecyltrimethylammonium chloride, etc.), etc.

[0050] In some embodiments of the present invention, the resin is selected from TOUGH resin, which has excellent flexibility. It can not only better combine between the first substrate 1 and the second substrate 3, but also cooperate with the formed array structure 2 to further enhance the flexibility of the ultra-thin flexible heat sink.

[0051] Furthermore, the substance with hydrophilic groups doped in the TOUGH resin is selected from the emulsifier, and 3%-8% of the emulsifier is added to the TOUGH resin, thereby significantly improving the surface energy of the unit body formed by the resin, making it exhibit excellent hydrophilic properties, and greatly improving the surface properties of the material.

[0052] This embodiment also proposes a preparation method, which is used to prepare the above-mentioned pure polymer ultra-thin flexible heat spreader without electromagnetic shielding, such as Figure 5 As shown, the preparation method comprises the following steps:

[0053] S1: Prepare the first substrate 1 and the second substrate 3.

[0054] In some embodiments of the present invention, the thickness of the first substrate 1 or the second substrate 3 is 0.025-0.075 mm.

[0055] In some embodiments of the present invention, the first substrate 1 or the second substrate 3 includes but is not limited to a polyimide film, a polyethylene terephthalate film, a polyphenylene sulfide film, a polyurethane film, a composite film of multiple films, or a composite film of multiple materials.

[0056] The first substrate 1 and the second substrate 3 may be made of the same material or different materials.

[0057] S2: Perform integrated 3D printing on the first substrate 1 to prepare a unit body and form an array structure 2.

[0058] In some embodiments of the present invention, ultra-high precision photo-curing 3D printing technology can be used in combination with micro-scale 3D printing additive manufacturing technology to perform fine processing on the array structure 2 to ensure high-strength and high-stability bonding between it and the first substrate 1.

[0059] This process not only fully utilizes the advantages of advanced manufacturing technology, but also optimizes the internal structure of the array structure 2 at the micro level, improving its overall performance and durability.

[0060] In some embodiments of the present invention, the array structure 2 includes but is not limited to linear, honeycomb, maze, three-dimensional, microchannel and mixed forms, all of which are manufactured on the first substrate 1 in an integrated manner through precise 3D printing microscale technology.

[0061] The array structure 2 is formed by a series of closely arranged units, showing a high degree of structural integration and functionality. In the application scenario of pure polymer ultra-thin flexible heat spreader, the array structure 2 not only serves as an efficient liquid wick to achieve efficient absorption and distribution of liquid, but also serves as a support column to provide the necessary mechanical support for the heat spreader, ensuring its stability and reliability during operation. This design cleverly combines functionality and structural stability, providing strong support for the high-performance application of pure polymer ultra-thin flexible heat spreader.

[0062] Furthermore, the array structure 2 can be designed to be homogeneous or heterogeneous, with a specific spacing, and can form a liquid wick and a support column (unit body) in the heat sink cavity 5.

[0063] In some embodiments of the present invention, the array structure 2 can be composed of unit bodies with a size of 500 μm-2000 μm in length, 500 μm-2000 μm in width, and 140 μm-2000 μm in height arranged in different numbers of arrays, and the unit body size is preferably 500 μm in length, 500 μm in width, and 140 μm in height, ensuring the high consistency of the structure. In the cavity 5, the liquid wick and the support column structure realize the layout of gas and liquid coplanarity, further optimizing the heat exchange efficiency.

[0064] In some embodiments of the present invention, the total volume of the cavity 5 after array processing is 800μ-90mm*500μm-90mm*140μm-2000μm, preferably 800μm*500μm*140μm. This design not only ensures the compactness of the structure, but also realizes the effective management and distribution of thermal energy on a microscopic scale, demonstrating its excellent performance and innovative value in the field of thermal management technology.

[0065] In some embodiments of the present invention, the array structure 2 is formed by using a photocurable resin slurry through a 3D printing device with precisely controlled printing parameters.

[0066] Photocurable resin slurry enables precise control of printing parameters, thereby shaping complex and precise 3D structures.

[0067] The present invention adopts a photocurable resin with good flexibility and adds 3%-8% emulsifier to the resin. Compared with the problems of low surface energy, insufficient hydrophilicity and insufficient flexibility of traditional photocurable resin slurry after curing, the present invention significantly improves the surface energy of the resin after curing, so that it exhibits excellent hydrophilicity, greatly improves the surface properties of the material, and has the advantages of high thermal conductivity, temperature resistance, good flexibility and the like.

[0068] The present invention achieves a firm bond between the array structure 2 and the first substrate 1 and the second substrate 3 and improves the hydrophilicity by precisely controlling printing parameters and selecting and optimizing resins, thereby ensuring its long-term stability and reliability in complex environments.

[0069] S3: cutting and gluing the packaging edge of the first substrate 1 , and placing the injection tube 4 and the sealing material at the tail thereof.

[0070] In some embodiments of the present invention, the designed array structure 2 is accurately printed on the first substrate 1 using photo-curing 3D printing technology, and the printed first substrate 1 and the second substrate 3 are bonded to form a composite board.

[0071] In order to ensure a tight connection between the first substrate 1 and the second substrate 3 , the present invention uses a specific heat-sealing adhesive and uses a heat-sealing device to perform heat-compression packaging.

[0072] In some embodiments of the present invention, the heat sealing adhesive includes but is not limited to 3M adhesive, polyethylene (PE), polypropylene (PP), polyimide (PI) heat sealing adhesive, nano adhesive, etc.

[0073] In some embodiments of the present invention, before gluing, ensure that the overlapping gluing area of ​​the first substrate 1 and the second substrate 3 is clean and dust-free, and reserve enough space at the tail to place the injection tube 4 and the final packaging edge after the injection tube 4 is cut off.

[0074] In some embodiments of the present invention, the thickness of the heat sealant is 0.02 mm-0.1 mm.

[0075] S4: using a heat sealer to heat-compress and seal the first substrate 1 and the second substrate 3 at the bonding edges.

[0076] In some embodiments of the present invention, after the first substrate 1 and the second substrate 3 are bonded together, it should be ensured that the two are tightly fitted. Next, the fitted edges are accurately placed in a heat sealer, which will implement a high-temperature and high-pressure hot-pressing packaging process by precisely controlling the temperature, pressure and packaging time to ensure that the formed package has sufficient strength and stability.

[0077] This series of operations is designed to achieve efficient and reliable substrate connection and meet high-quality packaging standards.

[0078] In some embodiments of the present invention, the temperature of heat-pressing sealing is 150° C.-290° C., and the pressure is 0.6 MPa-0.8 MPa.

[0079] Furthermore, the heat pressing sealing time is 30 minutes to 60 minutes.

[0080] The first substrate 1 and the second substrate 3 encapsulated with the injection tube 4 are called a composite substrate.

[0081] S5: Precisely inject liquid, perform primary degassing, and perform secondary degassing on the sealed first substrate 1 and the second substrate 3 .

[0082] In some embodiments of the present invention, the composite substrate is precisely injected with liquid through the injection pipe 4 at the rear by using a specific injection machine.

[0083] In some embodiments of the present invention, the amount of liquid injected into the cavity 5 accounts for 30%-90% of the volume of the cavity 5 .

[0084] In some embodiments of the present invention, the liquid (working fluid) injected through the injection tube 4 can be deionized water, ethanol, fluorinated liquid, acetone, etc.

[0085] In some embodiments of the present invention, the composite substrate after liquid injection is placed at a low temperature so that the working medium is at a low temperature, and the low-temperature liquid-injected composite substrate is degassed.

[0086] In some embodiments of the present invention, the degassing process may be designed to pump the gas pressure of the cavity 5 to below 100 Pa, which is beneficial to the gas-liquid phase change cycle in the cavity 5, thereby promoting efficient heat transfer.

[0087] S6: The sealing material is sealed by heating and pressurizing using a heat sealer, and the four parts of the liquid injection tube are cut off.

[0088] The composite substrate after injection and degassing is precisely pressed with the reserved final edge strip at high temperature and high pressure using a heat sealing device, so that the cavity 5 forms a closed space.

[0089] Then the liquid injection tube 4 is cut off to obtain a pure polymer ultra-thin flexible heat spreader without electromagnetic shielding.

[0090] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding, characterized in that: include: a first substrate; A plurality of unit bodies, wherein the plurality of unit bodies are arranged in an array on one side of the first substrate to form an array structure; a second substrate, the second substrate covering a side of the first substrate with the array structure, the second substrate, the first substrate and the array structure forming a sealed cavity; A working fluid, wherein the working fluid fills a portion of the cavity; The materials of the first substrate and the second substrate are selected from polymers, and the material of the unit body is selected from resins.

2. The pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding according to claim 1, characterized in that: The polymer is selected from one or more of polyimide, polyethylene terephthalate, polyphenylene sulfide and polyurethane.

3. The pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding according to claim 1, characterized in that: The thickness of the first substrate and the second substrate are independently 0.025 mm-0.075 mm.

4. The pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding according to claim 1, characterized in that: The first substrate and / or the second substrate is made of transparent material.

5. The pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding according to claim 1, characterized in that: The resin is doped with a substance having a hydrophilic group.

6. The pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding according to claim 5, characterized in that: The substance is selected from one or more of a surfactant, a hydrophilic polymer, an aqueous additive, a hydrophilic nanomaterial and a modifier.

7. A method for preparing a pure polymer ultra-thin flexible vapor chamber without electromagnetic shielding as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: preparing a first substrate and a second substrate; Performing integrated 3D printing on the first substrate to prepare a unit body and form an array structure; Cut and glue the packaging edge of the first substrate, and place the injection tube and sealing material at the tail; Using a heat sealer to heat-compress and seal the first substrate and the second substrate at the bonding edge; Precisely inject liquid, perform primary degassing, and perform secondary degassing on the sealed first substrate and the second substrate; The sealing material is sealed by heating and pressurizing using a heat sealer, and the injection tube portion is cut off.

8. The preparation method according to claim 7, characterized in that: The sealing temperature of the heat sealer is 150°C-290°C, and the pressure is 0.6MPa-0.8MPa.

9. The preparation method according to claim 7, characterized in that: The first substrate and the second substrate after injection are placed in a low temperature environment so that the working medium is at a low temperature, and then degassing is performed.

10. The preparation method according to claim 9, characterized in that: After the secondary degassing, the pressure of the cavity is less than 100Pa.

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