Foam structure and preparation method thereof, display module and display device

Abstract

The invention discloses a foam structure and a preparation method thereof, a display module and a display device. The preparation method comprises the steps that a foam mold is provided, and the foam mold comprises a plurality of polygonal holes arranged in an array; the polygonal holes are filled with foam slurry; the foam slurry is subjected to foaming curing treatment, demolding treatment is conducted after foaming curing treatment is completed, and the foam structure in the polygonal column shape is formed. According to the foam structure and the preparation method thereof, the display module and the display device provided by the embodiment of the invention, the foam structure is uniform in gap, stable in structure and uniform in morphology, has a lower heat conductivity coefficient, can achieve a better heat insulation effect, and can also have a better supporting effect. When the foam structure is used for a foam layer in the display module, the effects of uniform thickness and uniform heat insulation can be achieved, so that better heat insulation and extrusion resistance effects are achieved on the display module, and the problem that display is poor due to the fact that a display panel in the display module is heated is solved.

Description

Technical Field

[0001] The present invention relates to the field of display technologies, and in particular, to a foam structure, a preparation method thereof, a display module, and a display device. Background Art

[0002] With the increasing maturity of organic light-emitting diode (OLED) display technology, there are more and more flexible OLED display products. The curved screen design brought by flexible OLEDs has qualitatively improved the screen-to-body ratio, meeting consumers' pursuit of more beautiful electronic products.

[0003] In existing display modules, a driving chip (IC) may generate a relatively high temperature during operation. If not properly handled, display defects such as color deviation and brightness unevenness are likely to occur, affecting the display effect. Summary of the Invention

[0004] The present invention provides a foam structure, a preparation method thereof, a display module, and a display device to improve the display effect.

[0005] According to one aspect of the present invention, a preparation method of a foam structure is provided, including:

[0006] Providing a foam mold, the foam mold including a plurality of polygon holes arranged in an array;

[0007] Filling a foam slurry into the polygon holes;

[0008] Performing a foaming and curing treatment on the foam slurry, and performing a demolding treatment after the foaming and curing treatment is completed to form the foam structure having a polygon column shape.

[0009] According to another aspect of the present invention, a foam structure is provided, the foam structure being prepared by the above preparation method.

[0010] According to another aspect of the present invention, a display module is provided, including a display panel and a foam layer;

[0011] The foam layer is located on the backlight side of the display panel;

[0012] The foam layer includes at least one sub-foam layer;

[0013] The sub-foam layer includes a plurality of foam structures, the foam structure including the above foam structure.

[0014] According to another aspect of the present invention, a display device is provided, including the above display module.

[0015] In the technical solution of the embodiment of the present invention, during the foaming process of the foam slurry in the polygonal holes, it can expand fully and uniformly. The voids of the formed foam structure are uniform, the structure is stable, and the morphology is uniform. While retaining the buffering effect of the foam structure, it has a lower thermal conductivity, can achieve a better heat insulation effect, and can also have a better supporting effect. When this foam structure is used as the foam layer in the display module, it can achieve the effect of uniform thickness and uniform heat insulation, thereby playing a better role in heat insulation and anti-extrusion for the display module, and solving the problem of poor display caused by the heating of the display panel in the display module.

[0016] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a display module provided by an embodiment of the present invention;

[0019] Figure 2 It is a schematic flow structure diagram of a preparation method of a foam structure in the related art;

[0020] Figure 3 It is a schematic diagram of the heating expansion of a microsphere structure in the related art;

[0021] Figure 4 It is a schematic flow structure diagram of another preparation method of a foam structure in the related art;

[0022] Figure 5 It is a sliced image of a foam structure with closed-cell foaming in the related art;

[0023] Figure 6 It is a sliced image of a foam structure with open-cell foaming in the related art;

[0024] Figure 7 It is a schematic flow diagram of a preparation method of a foam structure provided by an embodiment of the present invention;

[0025] Figure 8 It is a schematic flow diagram of another preparation method of a foam structure provided by an embodiment of the present invention;

[0026] Figure 9 Schematic structural diagram of a foam mold provided by an embodiment of the present invention;

[0027] Figure 10 Enlarged schematic structural diagram of a foam mold provided by an embodiment of the present invention;

[0028] Figure 11 Schematic structural diagram of a structure for foaming and curing a foam slurry provided by an embodiment of the present invention;

[0029] Figure 12 Schematic structural diagram of a foam structure provided by an embodiment of the present invention;

[0030] Figure 13 Internal schematic structural diagram of a foam structure provided by an embodiment of the present invention;

[0031] Figure 14 Another internal schematic structural diagram of a foam structure provided by an embodiment of the present invention;

[0032] Figure 15 Schematic structural diagram of a foam slurry in a foam mold provided by an embodiment of the present invention;

[0033] Figure 16 Flow schematic diagram of a preparation method of yet another foam structure provided by an embodiment of the present invention;

[0034] Figure 17 Flow schematic diagram of a preparation method of still another foam structure provided by an embodiment of the present invention;

[0035] Figure 18 Schematic structural diagram of another display module provided by an embodiment of the present invention;

[0036] Figure 19 Schematic structural diagram of a foam layer provided by an embodiment of the present invention;

[0037] Figure 20 Enlarged schematic structural diagram of a foam layer provided by an embodiment of the present invention;

[0038] Figure 21 Schematic structural diagram of a force-bearing structure of a foam layer provided by an embodiment of the present invention;

[0039] Figure 22 Schematic structural diagram of a sub-foam layer provided by an embodiment of the present invention;

[0040] Figure 23 Schematic structural diagram of yet another display module provided by an embodiment of the present invention;

[0041] Figure 24 Schematic structural diagram of another foam layer provided by an embodiment of the present invention;

[0042] Figure 25 This is a schematic structural diagram of a display device provided by an embodiment of the present invention. Detailed implementation manners

[0043] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0045] Without departing from the spirit or scope of the present invention, various modifications and variations can be made to the present invention, which are obvious to those skilled in the art. Therefore, the present invention is intended to cover the modifications and variations of the present invention that fall within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the implementation manners provided by the embodiments of the present invention can be combined with each other without conflict.

[0046] Figure 1 This is a schematic structural diagram of a display module provided by an embodiment of the present invention. As Figure 1 shown, the display module includes a display panel 14, a foam layer 11 disposed on the backlight side of the display panel 14, and a driving chip 16.

[0047] In the related art, the foam structure of the foam layer 11 adopts a closed-cell foaming or open-cell foaming technology. Among them, closed-cell foaming means that the bubbles inside the foam structure are independent and closed and do not communicate with other bubbles; open-cell foaming means that the bubbles inside the foam structure can be connected, thereby forming an open network structure.

[0048] Specifically, Figure 2Schematic flow structure diagram of a preparation method of a foam structure in the related art, as Figure 2 shown, in the closed-cell foaming technology, wet glue 21 is coated on the gasket 20. The gasket 20 can be a polyethylene terephthalate (PET) gasket, but is not limited thereto. The wet glue 21 is dried to form dry glue 22, and foam slurry 23 is coated on the dry glue 22. The foam slurry 23 can be made of acrylate polymer, but is not limited thereto. Among them, the foam slurry 23 contains microsphere structures 24, and the foam slurry 23 is heated to foam the foam slurry 23.

[0049] Furthermore, Figure 3 Schematic diagram of the heating expansion of a microsphere structure in the related art, as Figure 3 shown, the microsphere structure 24 includes a core 241 and a shell 242 that wraps the core 241. The core 241 can be composed of liquid hydrocarbon, which is liquid at room temperature and can be vaporized when heated; the shell 242 can be composed of acrylonitrile co-polymers, which is solid at room temperature and can be softened when heated.

[0050] As Figure 2 and Figure 3 shown, when the foam slurry 23 is heated, the core 241 (liquid hydrocarbon) is vaporized by heat, the internal pressure of the microsphere structure 24 increases, the shell 242 is softened by heat, so that the volume of the microsphere structure 24 expands and the shell 242 becomes thinner, forming a closed-cell foamed foam structure 25.

[0051] In another related art, Figure 4 Schematic flow structure diagram of another preparation method of a foam structure in the related art, as Figure 4 shown, in the open-cell foaming technology, wet glue 21 is coated on the gasket 20, the wet glue 21 is dried to form dry glue 22, and foam slurry 23 is coated on the dry glue 22. The foam slurry 23 is further heated to foam the foam slurry 23. Among them, the foam slurry 23 can be made of acrylate polymer. During the heating process, the foam slurry 23 releases gas to form microcavities 27 of an open-cell foamed foam structure 26.

[0052] Continuing to refer to Figure 1 , when the display module works, the temperature at the driving chip 16 rises, and the heat will be transmitted upward along the foam layer 11.

[0053] Figure 5It is a sliced image of a foam structure with closed-cell foaming in the related art. Figure 6 It is a sliced image of a foam structure with open-cell foaming in the related art, as Figure 5 and Figure 6 shown. The inventor has found through research that the foam structure formed by using closed-cell foaming or open-cell foaming technology has the problem of uneven internal voids. This will lead to the problem of uneven thickness of the foam layer 11 in different regions. In the regions with thinner thickness, the heat insulation effect of the foam layer 11 is not good, which will cause the temperature to be transmitted to the display panel 14 too quickly, and then cause the display panel 14 to have an instant high temperature and display defects. At the same time, the uneven internal voids will also cause the foam layer 11 to have areas where foaming is not sufficient. Thus, when the display module is working, the areas where foaming is not sufficient will undergo secondary foaming under the influence of heat, changing the structure of the foam layer 11 and affecting its heat insulation in different regions, which may lead to large temperature differences in different regions of the display panel 14, causing display defects such as color deviation and brightness unevenness.

[0054] Based on the above technical problems, Figure 7 It is a schematic flow chart of a preparation method of a foam structure provided by an embodiment of the present invention. Figure 8 It is a schematic flow chart of another preparation method of a foam structure provided by an embodiment of the present invention, as Figure 7 and Figure 8 shown. The preparation method includes:

[0055] S11. Provide a foam mold, where the foam mold includes a plurality of polygon holes arranged in an array.

[0056] Among them, the foam mold is a tool for manufacturing a foam structure with a specific shape.

[0057] Figure 9 It is a schematic structural diagram of a foam mold provided by an embodiment of the present invention. Figure 10 It is an enlarged schematic structural diagram of a foam mold provided by an embodiment of the present invention, as Figure 9 and Figure 10 shown. The foam mold includes a plurality of polygon holes 30. The polygon holes 30 can be triangular holes, square holes, rectangular holes, hexagonal holes or other geometric shapes. Figure 9 Only the case where the polygon hole 30 is a hexagonal hole is taken as an example for illustration in , but it is not limited thereto.

[0058] Furthermore, arranging a plurality of polygon holes 30 in an array helps to improve the uniformity of subsequent foaming of the foam slurry and the structural stability of the formed foam structure.

[0059] Exemplarily, as Figure 9 and Figure 10As shown, taking the polygon hole 30 as a hexagonal hole as an example for illustration, the polygon holes 30 are closely arranged to form a structure similar to a honeycomb. This layout can maximize the utilization of space, which helps to improve the uniformity during the subsequent foaming of the foam slurry and the structural stability of the formed foam structure.

[0060] In other embodiments, the polygon holes 30 can also adopt other arrangement methods. For example, when the polygon holes 30 are square holes or rectangular holes, the polygon holes 30 can be arranged at right angles to form a regular grid pattern, but it is not limited thereto.

[0061] S12. Fill the polygon holes with the foam slurry.

[0062] Specifically, first, a suitable foam slurry is formulated according to the performance requirements of the foam structure. The foam slurry can include a foaming polymer system such as polymers (e.g., acrylate, polyurethane, polyethylene, etc.), and functional additives such as a foaming agent, a crosslinking agent, and a flame retardant can be added as needed.

[0063] For example, the foam slurry includes an acrylate polymer. The acrylate polymer has good elasticity and flexibility. The foam structure made from it can quickly return to its original state after being compressed and can withstand repeated compression and stretching without damage. At the same time, the acrylate polymer also has excellent adhesion performance and can firmly adhere to various surfaces, which is crucial for ensuring the connection between individual foam structures to form a foam layer and the tight fit with the display panel or other components.

[0064] Furthermore, the uniformly stirred foam slurry is injected into the polygon holes of the foam mold. Among them, for a regularly arranged polygon hole array, an appropriate amount of foam slurry can be directly poured onto the foam mold, and the slurry can be made to flow naturally into each polygon hole by tilting the foam mold, but it is not limited thereto.

[0065] In other embodiments, the foam slurry can also be injected in a vacuum environment to achieve uniform distribution of the foam slurry inside each polygon hole, avoiding the occurrence of bubbles or voids, which is beneficial to ensuring the consistency and integrity of the final foam structure. The embodiments of the present invention do not make specific limitations on this.

[0066] S13. Perform foaming and curing treatment on the foam slurry, and perform demolding treatment after the foaming and curing treatment is completed to form a foam structure with a polygon column shape.

[0067] Specifically, Figure 11 is a schematic structural diagram of a foaming and curing treatment of a foam slurry provided by an embodiment of the present invention. As Figure 11As shown, the foam mold filled with the foam slurry 31 can be placed in a heating device for foaming and curing. During this process, the foam slurry 31 releases gas under the action of heating or chemical initiators, forming a large number of tiny bubbles inside the foam slurry 31, so that the material expands and fills the polygonal holes 30 in the foam mold. Each polygonal hole 30 can be regarded as a "micro reaction chamber" for accommodating the foam slurry 31 and guiding its foaming and molding.

[0068] After the foaming and curing process is completed, cooling and demoulding are performed to take out the solidified foam structure. Since the foam slurry 31 expands and takes shape in the polygonal hole 30 of the foam mold, the formed foam structure presents a polygonal column shape matching the polygonal hole.

[0069] Furthermore, multiple foam structures (polygonal column shape) can be closely arranged to form a foam layer for use in a display module. In the process of arranging multiple foam structures, adjacent foam structures are in contact with each other, and the adjacent foam structures can be connected by an adhesive. For example, when the material of the foam structure is an acrylate polymer, since the acrylate polymer has good surface energy and adhesiveness, an acrylate-based or other compatible adhesive can be used to bond the multiple foam structures to form a foam layer, but it is not limited thereto.

[0070] Optionally, the temperature of the foaming and curing treatment is 80° C. to 100° C. Within this temperature range, the reaction of the foam slurry can be fully carried out to ensure that the formed foam structure has sufficient strength and stability and avoid local collapse or insufficient foaming.

[0071] Optionally, the foaming and curing treatment time is set to 2 hours or more. Long-term heating helps to evenly diffuse the released gas throughout the foam slurry to form a stable pore structure, while a shorter time may result in incomplete foaming, leaving more unfoamed areas, affecting the thermal insulation performance of the foam structure.

[0072] Optionally, the foaming and curing treatment of the foam slurry in the foam mold may adopt closed-cell foaming or open-cell foaming technology, which will not be described in detail here.

[0073] Figure 12 A schematic diagram of a foam structure provided by an embodiment of the present invention, Figure 13 A schematic diagram of the internal structure of a foam structure provided by an embodiment of the present invention, such as Figure 12 and Figure 13As shown, compared with the foam structure not formed by a foam mold in the related art, the foam structure prepared by the above preparation method can expand fully and uniformly during the foaming process in the polygonal holes 30. The voids of the formed foam structure are uniform, the structure is stable, and the morphology is uniform. While retaining the buffering effect of the foam structure, it has a lower thermal conductivity, can achieve a better heat insulation effect, and can also have a better supporting effect. When this foam structure is used as the foam layer in a display module, it can achieve a uniform thickness and a uniform heat insulation effect, thereby playing a better heat insulation and anti-extrusion role for the display module, and solving the problem of poor display caused by the display panel being heated in the display module.

[0074] Figure 14 The following is an internal structure schematic diagram of another foam structure provided by an embodiment of the present invention. As Figure 14 shown, optionally, the foam slurry includes cellulose fibers 32.

[0075] Among them, cellulose fiber 32 is a natural polymer material derived from plant cell walls, and its main component is cellulose. Cellulose fibers can be extracted from a variety of plant resources, including but not limited to cotton, wood, bamboo, and hemp plants, etc.

[0076] As Figure 14 shown, in this embodiment, adding cellulose fiber 32 to the foam slurry, cellulose fiber 32 can form a three-dimensional network structure in the foam slurry, improving the overall tensile strength and tear resistance of the formed foam structure. At the same time, cellulose fiber 32 helps to maintain the integrity of the foam structure, can better return to its original state after the foam structure is squeezed, and provides a better anti-extrusion effect. When the foam structure is used as the foam layer in a display module, it helps to ensure the thickness uniformity of the foam layer, thereby achieving a better heat insulation performance, being beneficial to adjusting the temperature distribution, preventing local overheating, and solving the problem of poor display caused by the display panel being heated in the display module.

[0077] Optionally, the weight percentage of cellulose fiber in the foam slurry is a, where 1% ≤ a ≤ 5%.

[0078] Among them, adding a small amount of cellulose fiber (1% to 5%) to the foam slurry can effectively improve its tensile strength, compressive resistance, and elastic modulus without significantly changing the original foam structure.

[0079] Meanwhile, when the foam slurry foams, it needs to have good fluidity and foaming ability to ensure that it can smoothly fill the polygonal holes of the foam mold and form a uniform pore structure. In this embodiment, when the cellulose fibers added adopt the above weight ratio range, the cellulose fibers can be evenly dispersed in the foam slurry to form an effective reinforcing network structure, avoiding problems such as agglomeration or decreased fluidity caused by excessive addition, which hinders gas release and results in poor foaming or uneven porosity.

[0080] Optionally, the cellulose fiber is nano-cellulose, which refers to cellulose fibers with diameters ranging from dozens to hundreds of nanometers and lengths ranging from hundreds of nanometers to several micrometers. When nano-cellulose is introduced into the foam structure and forms a network structure inside the foam structure, it can significantly improve the overall tensile strength and tear resistance of the foam structure, and help maintain the integrity of the foam structure. The foam structure can better return to its original state after being compressed, providing a better buffering effect. At the same time, nano-cellulose itself also has certain heat insulation properties. When the foam structure is used as the foam layer in the display module, it is beneficial to help regulate the temperature distribution, prevent local overheating, and solve the problem of poor display caused by the heating of the display panel in the display module.

[0081] Optionally, the foam slurry includes conductive particles.

[0082] Among them, adding conductive particles with good thermal conductivity to the foam slurry can significantly improve the thermal conductivity of the foam structure, so as to help the heat quickly spread out from the hot spot area.

[0083] Specifically, when the foam structure is used as the foam layer in the display module, the high thermal conductivity of the conductive particles enables the heat to be transferred more effectively inside the foam layer, reducing the occurrence of local overheating, thereby improving the thermal stability of the entire display module, being beneficial to help regulate the temperature distribution, prevent local overheating, and solve the problem of poor display caused by the heating of the display panel in the display module.

[0084] Optionally, the conductive particles include materials such as carbon powder, graphite, polythiophene, nano-silver, etc., but are not limited thereto. Among them, carbon powder has low cost and is easy to obtain, and carbon powder has good dispersibility and stability; graphite is a good thermal conductive material and can significantly improve the thermal conductivity of the foam structure; the polythiophene material itself has certain mechanical strength and elasticity, which can provide certain structural support for the foam structure. At the same time, polythiophene has good flexibility and processability, and is suitable for use in flexible display modules; nano-silver is a material with very good thermal conductivity among metals. Due to its large specific surface area, it can form a continuous thermal conduction network at a low concentration, significantly improving the thermal conductivity of the foam structure.

[0085] Optionally, the weight percentage of the conductive particles in the foam slurry is b, where 0.5% ≤ b ≤ 1.5%.

[0086] Among them, adding a small amount of conductive particles (0.5% to 1.5%) to the foam slurry can effectively improve its thermal conductivity without significantly affecting the density, flexibility, and buffering performance of the original foam structure, and avoid problems such as hardening and brittleness of the foam caused by excessive conductive particles.

[0087] In addition, conductive particles (especially metal-based or high-performance carbon-based particles) are usually relatively expensive, and adding conductive particles in a low proportion also helps to control the overall material cost.

[0088] Figure 15 The following is a schematic structural diagram of a foam slurry in a foam mold provided by an embodiment of the present invention, as Figure 15 shown. Optionally, the filling height of the foam slurry 31 in the polygonal hole 30 is H1, and the depth of the polygonal hole 30 is H2, where (3 / 4)*H2 ≤ H1 ≤ H2.

[0089] Among them, if the filling height H1 of the foam slurry 31 in the polygonal hole 30 is less than 75% of the depth H2 of the polygonal hole 30, it may cause the foam slurry 31 to not completely fill the polygonal hole 30 after foaming, wasting the capacity of the foam mold, and easily causing local collapse of the foam structure, affecting the strength consistency of the foam structure.

[0090] In this embodiment, the filling height H1 of the foam slurry 31 in the polygonal hole 30 is not less than 75% of the depth H2 of the polygonal hole 30, which can effectively utilize the space of the foam mold, improve the yield rate of a single production, and is beneficial to ensuring that the foam slurry 31 is fully filled and evenly foamed in the polygonal hole 30, avoiding defects such as collapse.

[0091] Furthermore, the foam slurry 31 will expand and foam during the heating or chemical reaction process. Reserving a certain amount of top space (i.e., H1 ≤ H2) can prevent the foam slurry 31 from overflowing and causing material waste or problems such as uneven surfaces.

[0092] Optionally, the material of the foam mold includes at least one of polydimethylsiloxane, metal, and polymethyl methacrylate.

[0093] Among them, due to its flexibility and low surface energy, polydimethylsiloxane (PDMS) can make the foam structure easily demold from the foam mold with a complex three-dimensional structure, reducing the risk of damage. At the same time, PDMS can accurately replicate fine structures at the micron and even nanometer levels, making it suitable for high-precision mold manufacturing. In addition, the price of PDMS is relatively low, and foam molds can be prepared by simple methods such as spin coating and casting, reducing the production cost.

[0094] Metallic materials (such as stainless steel, aluminum, copper, etc.) have extremely high mechanical strength and hardness, and can withstand large stresses and wear. The foam molds made of metallic materials have a long service life and are suitable for mass production and repeated use. Moreover, metallic materials usually have a high melting point and thermal stability, enabling the foam mold to maintain its structural integrity in high-temperature environments.

[0095] The foam mold made of polymethyl methacrylate (PMMA) material has good dimensional stability after molding and is not easily deformed, making it suitable for high-precision mold manufacturing. At the same time, the cost of PMMA is relatively low and the processing difficulty is small.

[0096] Figure 16 It is a schematic flowchart of another preparation method for the foam structure provided by the embodiment of the present invention. Figure 17 It is a schematic flowchart of yet another preparation method for the foam structure provided by the embodiment of the present invention, as Figure 16 and Figure 17 shown. Optionally, before providing the foam mold, it further includes:

[0097] S101: Coating a photoresist layer on the substrate.

[0098] Specifically, select a suitable substrate (such as a glass substrate, a silicon wafer, etc.), and spin coat a layer of photoresist on its surface to form a photoresist layer.

[0099] Among them, the photoresist can be a positive photoresist or a negative photoresist, and those skilled in the art can select according to actual needs. For example, if a higher resolution (such as sub-micron level) needs to be achieved, a positive photoresist can be selected to enable a more delicate pattern; the negative photoresist is relatively easier to operate.

[0100] S102: Performing exposure and development operations on the photoresist layer to form a photoresist template, and the photoresist template includes a plurality of polygonal columns arranged in an array.

[0101] In this embodiment, 3D lithography technology can be used to design a corresponding mask pattern according to the specific size and arrangement of the required polygon array, so as to prepare the polygon array pattern on the photoresist layer. Through exposure and development operations, a photoresist template including a plurality of polygon columns arranged in an array is formed.

[0102] Specifically, during the exposure process, a mask can be used to irradiate the photoresist layer with ultraviolet light (or electron beam exposure), causing chemical changes in the photoresist layer. During the development process, according to the type of photoresist used (positive or negative), a suitable developer is selected to remove the unexposed or exposed parts to obtain the required polygon column structure.

[0103] Among them, for a positive photoresist layer, in the unexposed state, the positive photoresist is insoluble in the developer. After ultraviolet light or electron beam exposure, the photosensitizer in the positive photoresist undergoes chemical changes, making the exposed area soluble in the developer. During the development process, the exposed area is dissolved, leaving the unexposed part to form the required polygon column structure.

[0104] For a negative photoresist layer, in the unexposed state, the negative photoresist is soluble in the developer. After ultraviolet light or electron beam exposure, the polymer in the negative photoresist undergoes a cross-linking reaction, making the exposed area insoluble in the developer. During the development process, the unexposed area is dissolved, leaving the exposed part to form the required polygon column structure.

[0105] S103. Cover the polygon columns of the photoresist template with the foam mold material.

[0106] Specifically, the foam mold material (such as polydimethylsiloxane, etc.) can be evenly covered on the photoresist template by means of spin coating, spraying or pouring, etc., to ensure that the gaps between all polygon columns are filled with the foam mold material, so as to use the photoresist template as a negative mold to replicate the corresponding positive mold structure.

[0107] S104. Cure the foam mold material at the first temperature to form a foam mold.

[0108] Specifically, according to the different selected foam mold materials, the corresponding first temperature and time are set, and the foam mold material is heated and cured. After curing is completed, the cured foam mold material is peeled off to obtain a foam mold with a reverse polygon hole array for subsequent perfusion and molding of the foam slurry.

[0109] It can be understood that the thickness of the photoresist layer can determine the height of the polygonal columns in the photoresist template. The height of the polygonal columns in the photoresist template can determine the depth of the polygonal holes in the foam mold. The depth of the polygonal holes in the foam mold can directly determine the height of the finally formed foam structure. Therefore, the thickness of the photoresist layer can be set according to the height of the finally required foam structure.

[0110] Among them, through lithography technology, it is possible to achieve fine pattern transfer at the micron and even nanometer levels, ensuring that the polygonal holes in the foam mold have extremely high dimensional accuracy and position accuracy. At the same time, each lithography process can produce the same pattern, making the batch-produced foam molds highly consistent and reproducible. Further, according to different application requirements, the mask pattern can be quickly adjusted, so as to easily realize polygonal hole structures with various complex shapes and arrangements. It can be understood that once the foam mold is made, the subsequent steps of filling the foam slurry and foaming and curing become simpler and more direct, which can reduce the complexity of the overall production process.

[0111] Optionally, the foam mold material includes a polydimethylsiloxane main agent and a curing agent, and the weight ratio between the polydimethylsiloxane main agent and the curing agent is c, where 8 ≤ c ≤ 10.

[0112] Among them, the polydimethylsiloxane main agent is mainly composed of long-chain polydimethylsiloxane and has good flexibility and elasticity.

[0113] The curing agent contains a cross-linking agent and can chemically react with the polydimethylsiloxane main agent to promote the transformation of polydimethylsiloxane from a liquid state to a solid state.

[0114] The foam mold material including the polydimethylsiloxane main agent and the curing agent can make the foam mold material have good fluidity to fill in details, and at the same time have sufficient mechanical strength to support subsequent demolding operations.

[0115] In this embodiment, setting the weight ratio between the polydimethylsiloxane main agent and the curing agent within the range of 8:1 to 10:1 can balance the softness and mechanical strength of the formed foam mold. At the same time, an appropriate cross-linking density is achieved, which helps to reduce the adhesion on the surface of the cured foam mold and facilitates demolding from complex structures, reducing the risk of damage.

[0116] Among them, the specific weight ratio between the polydimethylsiloxane main agent and the curing agent can be set according to actual needs. For example, setting the specific weight ratio between the polydimethylsiloxane main agent and the curing agent to 10:1, when using the photoresist template for mold replication, the foam mold material can better conform to the details of the photoresist template and achieve higher-fidelity replication. At the same time, it is easy to demold and reduces the risk of damage, but it is not limited to this.

[0117] Optionally, the polydimethylsiloxane base agent and the curing agent are mixed and stirred at room temperature to form a foam mold material. Among them, the stirring time can be greater than or equal to 30 min to ensure the full mixing of the polydimethylsiloxane base agent and the curing agent, and avoid local strength differences or structural defects in the foam mold caused by incomplete curing or over-curing in local areas.

[0118] Optionally, after the polydimethylsiloxane base agent and the curing agent are mixed and stirred at room temperature, a vacuum device is used to remove the bubbles brought by the stirring. Among them, by reducing the pressure (vacuum pumping), the gas dissolved in the foam mold material can expand rapidly and escape from the foam mold material, so as to achieve the purpose of removing bubbles, ensure the smooth surface and complete structure of the formed foam mold, and improve the overall quality and precision of the foam mold.

[0119] Optionally, the first temperature is d, where 80°C ≤ d ≤ 100°C.

[0120] Among them, a lower first temperature will make the curing speed of the foam mold material relatively slow, which can reduce the thermal stress caused by rapid heating or cooling, thereby reducing the risk of cracks or deformation of the foam mold. A higher first temperature will significantly accelerate the cross-linking reaction speed of the foam mold material, and the curing process can be completed in a shorter time, improving production efficiency. However, if the first temperature is too high, it may cause the surface of the foam mold to turn yellow or produce other defects.

[0121] In this embodiment, by setting the first temperature in the range of 80°C to 100°C, it helps to reduce the thermal stress caused by the temperature difference while ensuring production efficiency, and avoid defects such as cracks or deformation of the foam mold.

[0122] Optionally, the heating and curing time of the foam mold material is greater than or equal to 2 h. Among them, sufficient curing time can ensure the complete cross-linking reaction between the polydimethylsiloxane base agent and the curing agent, and avoid insufficient strength in some areas of the foam mold caused by unreacted areas. At the same time, certain thermal stress and shrinkage stress will be generated during the curing process of the foam mold material. A longer curing time helps the slow release of these stresses and reduces the risk of deformation and cracking of the foam mold.

[0123] Continue to refer to Figure 8 and Figure 17 , optionally, a foam mold is provided, including:

[0124] The surface of the foam mold is subjected to silanization treatment.

[0125] Among them, the silanization treatment refers to introducing a low surface energy silane molecular layer (such as perfluorosilane, trimethylchlorosilane, etc.) on the surface of the foam mold, and changing the surface properties of the material through chemical bonding or physical adsorption, which is a surface modification technology.

[0126] After the silanization treatment, the surface of the foam mold has extremely low surface energy, making it difficult for the foam structure to adhere, easier to demold, and reducing the damage rate of the foam structure.

[0127] At the same time, the surface of the foam mold after silanization treatment is smoother, which helps the foam slurry to flow evenly and fill the microstructures precisely, improving the fidelity of the foam structure.

[0128] Optionally, the polygonal column includes a regular hexagonal prism.

[0129] Among them, when the foam structure adopts the shape of a regular hexagonal prism, it can achieve close packing of the foam structure on a two-dimensional plane, forming a foam layer with a honeycomb structure. The honeycomb structure foam layer can effectively block heat transfer, so that the foam layer has better heat insulation effect.

[0130] At the same time, due to its symmetry and regularity, the shape of the regular hexagonal prism can disperse the externally applied pressure more evenly, reduce the phenomenon of local stress concentration, and improve the stability of the foam structure. The foam layer formed by arranging the foam structure in a honeycomb pattern can effectively resist compression deformation and enhance its support strength.

[0131] Optionally, the height of the polygonal column is H3, and 50μm ≤ H3 ≤ 200μm.

[0132] Among them, the height H3 of the polygonal column can be understood as the vertical distance between one bottom surface (polygon) and another parallel bottom surface. The polygonal column with a lower height can provide better mechanical support and compressive resistance, while the polygonal column with a higher height is relatively easier to manufacture, reducing the requirement for processing accuracy.

[0133] In this embodiment, setting the height H3 of the polygonal column of the foam structure in the range of 50μm to 200μm can provide better mechanical support and compressive resistance while achieving good foaming expansion control and being relatively easy to manufacture.

[0134] Optionally, the polygonal width of the polygonal column is e, and 1μm ≤ e ≤ 5μm.

[0135] Among them, the polygonal width e can be understood as the diameter of the circumscribed circle of its polygonal surface, or understood as the maximum width of the polygonal surface, that is, the longest distance between any two points of the polygon. For a regular polygon, the polygonal width e can be the distance between opposite vertices; for an irregular polygon, it can be the maximum distance between any two points.

[0136] It is understandable that a polygon column with a smaller width can provide better mechanical support and compressive resistance, while a polygon column with a larger width is relatively easy to manufacture, reducing the requirements for processing accuracy.

[0137] In this embodiment, the polygon width e of the polygon column provided with the foam structure ranges from 1 μm to 5 μm, which can provide better mechanical support and compressive resistance while achieving good foam expansion control and being relatively easy to manufacture.

[0138] Based on the same inventive concept, the embodiments of the present invention also provide a foam structure, which is prepared by the preparation method described in any embodiment of the present invention. Therefore, the foam structure provided by the embodiments of the present invention has the technical effects of the technical solutions in any of the above embodiments, and the explanations of the same or corresponding structures and terms as those in the above embodiments will not be repeated here.

[0139] Based on the same inventive concept, the embodiments of the present invention also provide a display module. Figure 18 It is a schematic structural diagram of another display module provided by the embodiment of the present invention. As Figure 18 shown, the display module includes a display panel 14 and a foam layer 11, and the foam layer 11 is located on the backlight side of the display panel 14. The foam layer 11 includes at least one sub-foam layer 110, and the sub-foam layer 110 includes a plurality of foam structures 40, and the foam structure 40 includes the foam structure described in any embodiment of the present invention.

[0140] Among them, as Figure 18 shown, the display panel 14 may include a liquid crystal display panel (LCD), an organic light-emitting diode (OLED) display panel, a light-emitting diode (LED) display panel, a mini light-emitting diode (Mini LED) display panel, or a micro light-emitting diode (Micro LED) display panel, etc. The embodiments of the present invention do not specifically limit the type of the display panel 14.

[0141] The foam layer 11 is disposed on the backlight side of the display panel 14 and can perform functions such as buffering, heat insulation, and shock absorption. The foam layer 11 may be stacked by one or more sub-foam layers 110, and each sub-foam layer 110 may have the same or different functional characteristics.

[0142] Each sub-foam layer 110 contains a plurality of foam structures 40, and the foam structure 40 is designed based on the polygon column structure (such as a regular hexagonal column) described above in the present invention.

[0143] Among them, the foam structure 40 is prepared by using the preparation method described in any embodiment of the present invention, so that the internal voids of the foam structure 40 are uniform, the structure is stable and the morphology is uniform, and it has a lower thermal conductivity, which can achieve a better heat insulation effect. Moreover, its polygonal column structure has good compressive deformation resistance, can absorb energy and quickly return to its original state when subjected to external force impact, and has a better support effect. When the foam structures 40 are stacked to form the foam layer 110 in the display module, a uniform thickness and uniform heat insulation effect can be achieved, thereby playing a better heat insulation and anti-extrusion role for the display module, and solving the problem of poor display caused by the heating of the display panel in the display module.

[0144] Optionally, as Figure 18 shown, the thickness of the foam layer 11 is H4, and 100μm ≤ H4 ≤ 200μm.

[0145] Among them, since the foam structure 40 in the foam layer 11 has a better heat insulation effect and support effect, setting the thickness H4 of the foam layer 11 to be between 100μm and 200μm can reduce the impact of the foam layer 11 on the overall thickness of the display module while meeting the required heat insulation effect and support effect, which is beneficial to realizing a thin and light design.

[0146] Optionally, as Figure 18 shown, the shape of the foam structure 40 includes a regular hexagonal prism.

[0147] Among them, the foam structure 40 adopts the shape of a regular hexagonal prism, which can realize the close packing of the foam structure 40 on a two-dimensional plane to form a foam layer 11 with a honeycomb structure. The honeycomb-structured foam layer 11 can effectively block heat transfer, so that the foam layer 11 has a better heat insulation effect.

[0148] At the same time, due to its symmetry and regularity, the shape of the regular hexagonal prism can disperse the externally applied pressure more evenly, reduce the phenomenon of local stress concentration, and improve the stability of the foam structure 40. The foam layer 11 formed by arranging the foam structures 40 in a honeycomb arrangement can effectively resist compression deformation and enhance its support strength.

[0149] It should be noted that in other embodiments, the foam structure 40 can also adopt other shapes, and the embodiments of the present invention do not make specific limitations in this regard.

[0150] Figure 19 is a schematic structural diagram of a foam layer provided by an embodiment of the present invention, Figure 20 is an enlarged schematic structural diagram of a foam layer provided by an embodiment of the present invention, Figure 21 is a schematic stress structure diagram of a foam layer provided by an embodiment of the present invention, as Figures 18 - 21As shown, optionally, in the sub-foam layer 110, the regular hexagonal face of the foam structure 40 is parallel to the thickness direction of the sub-foam layer 110.

[0151] Among them, as Figures 18 - 21 shown, the cross-section of the foam structure 40 is a regular hexagonal face.

[0152] In this embodiment, the regular hexagonal faces of the foam structures 40 are all parallel to the thickness direction of the sub-foam layer 110, which can achieve the close packing of the foam structures 40 in the thickness direction of the sub-foam layer 110, and then form a foam layer 11 with a honeycomb structure. At this time, the polygonal width of the foam structure 40 is consistent with the thickness of the sub-foam layer 110. Among them, the foam layer 11 with a honeycomb structure can effectively block heat transfer, so that the foam layer 11 has better heat insulation effect.

[0153] At the same time, the close packing of the foam structures 40 in the thickness direction of the sub-foam layer 110 can more evenly disperse the externally applied pressure, reduce the local stress concentration phenomenon, effectively resist compression deformation, and enhance its support strength.

[0154] Figure 22 The figure is a schematic structural diagram of a sub-foam layer provided by an embodiment of the present invention. As Figure 22 shown, optionally, in the sub-foam layer 110, the regular hexagonal face of the foam structure 40 is perpendicular to the thickness direction of the sub-foam layer 110.

[0155] Among them, as Figure 22 shown, in the sub-foam layer 110, the regular hexagonal faces of the foam structures 40 are all perpendicular to the thickness direction of the sub-foam layer 110 (such as the X direction), which can achieve the close packing of the foam structures 40 in the plane direction of the sub-foam layer 110, and then form a sub-foam layer 110 with a honeycomb structure. At this time, the height of the foam structure 40 is consistent with the thickness of the sub-foam layer 110. Among them, the sub-foam layer 110 with a honeycomb structure can effectively block heat transfer, so that the sub-foam layer 110 has better heat insulation effect.

[0156] At the same time, the close packing of the foam structures 40 in the plane direction of the sub-foam layer 110 can more evenly disperse the externally applied pressure, reduce the local stress concentration phenomenon, effectively resist compression deformation, and enhance its support strength.

[0157] Optionally, the foam structure 40 in at least one sub-foam layer 110 includes cellulose fibers.

[0158] Among them, the cellulose fibers have high tensile strength and toughness, which can improve the overall tensile strength and tear resistance of the foam structure 40; at the same time, the cellulose fibers can form a three-dimensional network structure in the foam structure 40, which helps to maintain the integrity of the foam structure 40.

[0159] In this embodiment, by setting that the foam structure 40 in at least one sub-foam layer 110 includes cellulose fibers, the compressive strength and resilience performance of at least one sub-foam layer 110 can be enhanced, enabling it to better absorb energy and quickly return to its original state when subjected to external impact, protecting the display panel 14 from damage. Meanwhile, it helps to ensure the thickness uniformity of the sub-foam layer 110, thereby achieving better heat insulation performance, facilitating the regulation of temperature distribution, preventing local overheating, and solving the problem of poor display caused by the heating of the display panel 14 in the display module.

[0160] It should be noted that the foam structure 40 of some sub-foam layers 110 in the foam layer 11 can be set to include cellulose fibers, or the foam structure 40 of all sub-foam layers 110 in the foam layer 11 can be set to include cellulose fibers. The embodiments of the present invention do not make specific limitations on this.

[0161] Figure 23 It is a schematic structural diagram of another display module provided by the embodiment of the present invention. Figure 24 It is a schematic structural diagram of another foam layer provided by the embodiment of the present invention. As Figure 23 and Figure 24 shown, optionally, at least one sub-foam layer 110 includes at least one first sub-foam layer 110A, and the foam structure 40 of the first sub-foam layer 110A includes conductive particles 33.

[0162] Among them, the foam structure 40 includes conductive particles 33 with good thermal conductivity, which can significantly improve the thermal conductivity of the foam structure 40, thereby enabling heat to quickly diffuse from the hot spot area.

[0163] In this embodiment, by setting that the foam structure 40 in at least one sub-foam layer 110 (such as the first sub-foam layer 110A) includes conductive particles 33, heat can be more effectively transferred inside the sub-foam layer 110, reducing the occurrence of local overheating, thereby improving the thermal stability of the entire display module, facilitating the regulation of temperature distribution, preventing local overheating, and solving the problem of poor display caused by the heating of the display panel in the display module.

[0164] It should be noted that the foam structure 40 of some sub-foam layers 110 in the foam layer 11 can be set to include conductive particles 33, or the foam structure 40 of all sub-foam layers 110 in the foam layer 11 can be set to include conductive particles 33. The embodiments of the present invention do not make specific limitations on this.

[0165] Continue to refer to Figure 23 and Figure 24Optionally, the display panel 14 includes a display sub-section 141, and the display module further includes a driver chip 16, which is electrically connected to the display panel 14 and is located on a side of the foam layer 11 away from the display sub-section 141. The at least one sub-foam layer 110 includes at least one second sub-foam layer 110B, and the second sub-foam layer 110B is an insulating layer. The first sub-foam layer 110A is located on a side of the second sub-foam layer 110B close to the driver chip 16.

[0166] Specifically, Figure 1 , Figure 18 and Figure 23 As shown, the display panel 14 includes a display sub-section 141 provided with a display area, and a plurality of sub-pixels arranged in an array are provided in the display area to realize an image display function.

[0167] The driver chip 16 is electrically connected to the display panel 14 and is responsible for driving the display panel 14 to display images. The foam layer 11 is located between the driver chip 16 and the display section 141. When the display module is working, the temperature of the driver chip 16 rises, and the heat is transferred along the foam layer 11 to the display section 141.

[0168] In this embodiment, if Figure 23 As shown, the foam layer 11 includes a first sub-foam layer 110A and a second sub-foam layer 110B. The foam structure 40 of the first sub-foam layer 110A includes conductive particles 33, so that the first sub-foam layer 110A has good thermal conductivity; the foam structure 40 of the second sub-foam layer 110B does not include conductive particles 33, so that the second sub-foam layer 110B has good thermal insulation.

[0169] Among them, the first sub-foam layer 110A is arranged on the side close to the driving chip 16, and the second sub-foam layer 110B is arranged on the side of the sheet 16 close to the display panel 14, so that the first sub-foam layer 110A can quickly conduct the heat generated by the driving chip 16, and the second sub-foam layer 110B can prevent the remaining heat from being transmitted to the display panel 14, thereby solving the poor display problem caused by the heating of the display panel 14.

[0170] Meanwhile, the second sub-foam layer 110B is an insulating layer, which can prevent the conductive particles 33 from affecting the display area circuit and prevent short circuit or leakage current problems.

[0171] Optional, such as Figure 1 , Figure 18 and Figure 23As shown, the display panel 14 further includes a rear folding portion 142 connected to the display section 141. The rear folding portion 142 can be used to bind the driving chip 16. For example, connection traces are provided on the rear folding portion 142 to connect the sub-pixels in the display area to the driving chip 16 through the connection traces. Among them, the rear folding portion 142 can be bent toward the backlight side of the display panel 14 so that the driving chip 16 is bent to the backlight side of the display panel 14, thereby reducing the width of the border and improving the visual effect of the display module.

[0172] Optionally, as Figure 1 、 Figure 18 and Figure 23 shown, the display module further includes an adhesive layer 18. The adhesive layer 18 can be used to attach the rear folding portion 142 to the backlight side of the display panel 14 to ensure the stability and reliability of the overall structure.

[0173] Optionally, as Figure 1 、 Figure 18 and Figure 23 shown, the display module further includes a conductive cloth 17. The conductive cloth 17 is located on the side of the driving chip 16 facing away from the foam layer 11, and the conductive cloth 17 is attached to the driving chip 16. The conductive cloth 17 has good electrical conductivity and can quickly dissipate static charges, reducing the risk of electrostatic discharge (ESD) and protecting the driving chip 16 from damage.

[0174] Optionally, as Figure 1 、 Figure 18 and Figure 23 shown, the display module further includes a copper layer 10. The copper layer 10 is located between the adhesive layer 18 and the foam layer 11. Copper has a relatively high thermal conductivity and can serve as an effective heat conduction path to quickly conduct the heat generated by the driving chip 16.

[0175] Optionally, as Figure 1 、 Figure 18 and Figure 23 shown, the display module further includes an embossed adhesive (Embo) layer 12. The embossed adhesive layer 12 is located between the foam layer 11 and the display section 141 and can strengthen the tightness of the attachment between the foam layer 11 and the display section 141. Among them, the embossed adhesive layer 12 can be printed with vertical and horizontal reticulations on the adhesive surface by applying pressure through a grid, thereby preventing the curling phenomenon caused by the shrinkage of the adhesive layer.

[0176] Optionally, as Figure 1 、 Figure 18 and Figure 23 shown, the display module further includes a polarizer 15. The polarizer 15 can be attached to the light-emitting side of the display panel 14 through an optical adhesive. The polarizer 15 can be used to filter polarized light in a specific direction in the incident light or the outgoing light, thereby improving the display quality.

[0177] Optionally, as Figure 1 , Figure 18 and Figure 23 shown, the display module further includes a cover plate 19, which is located on the side of the polarizer 15 away from the display panel 14 and can be used to prevent the display panel 14 from being scratched, impacted, and other physical damages. Among them, the material of the cover plate 19 may include glass, plastic, or other composite materials, etc., and the embodiments of the present invention do not make specific limitations on this.

[0178] Based on the same inventive concept, the embodiments of the present invention also provide a display device. Figure 25 is a schematic structural diagram of a display device provided by an embodiment of the present invention. As Figure 25 shown, the display device 50 includes the display module 51 described in any embodiment of the present invention. Therefore, the display device 50 provided by the embodiments of the present invention has the technical effects of the technical solutions in any of the above embodiments, and the same or corresponding structures and explanations of terms as those in the above embodiments will not be repeated here.

[0179] It should be understood that various forms of the processes shown above can be used, reordering, adding, or deleting steps. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions of the present invention can be achieved, and this is not limited herein.

[0180] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a foam structure, characterized in that Comprising: Providing a foam mold, the foam mold including a plurality of polygon holes arranged in an array; Filling foam slurry into the polygon holes; Performing foaming and curing treatment on the foam slurry, and performing demolding treatment after the foaming and curing treatment is completed to form the foam structure having a polygon column shape.

2. The preparation method according to claim 1, wherein The foam slurry includes cellulose fibers.

3. The preparation method according to claim 2, wherein The weight proportion of the cellulose fibers in the foam slurry is a, wherein 1% ≤ a ≤ 5%.

4. The preparation method according to claim 1, wherein The foam slurry includes conductive particles.

5. The preparation method according to claim 4, wherein The weight proportion of the conductive particles in the foam slurry is b, wherein 0.5% ≤ b ≤ 1.5%.

6. The preparation method according to claim 1, wherein The filling height of the foam slurry in the polygon holes is H1, the depth of the polygon holes is H2, and (3 / 4)*H2 ≤ H1 ≤ H2.

7. The preparation method according to claim 1, wherein The material of the foam mold includes at least one of polydimethylsiloxane, metal, and polymethyl methacrylate.

8. The preparation method according to claim 1, wherein Before providing the foam mold, it includes: Coating a photoresist layer on a substrate; Performing exposure and development operations on the photoresist layer to form a photoresist template, the photoresist template including a plurality of polygon columns arranged in an array; Covering a foam mold material on the polygon columns of the photoresist template; Curing the foam mold material at a first temperature to form the foam mold.

9. The preparation method according to claim 8, wherein The foam mold material includes a polydimethylsiloxane main agent and a curing agent; The weight ratio between the polydimethylsiloxane main agent and the curing agent is c, and 8 ≤ c ≤ 10.

10. The preparation method according to claim 8, wherein The first temperature is d, and 80°C ≤ d ≤ 100°C.

11. The preparation method according to claim 1, wherein The providing of the foam mold includes: Performing silanization treatment on the surface of the foam mold.

12. The preparation method according to claim 1, wherein The polygon column includes a regular hexagonal prism.

13. The preparation method according to claim 1, wherein The height of the polygon column is H3, and 50μm ≤ H3 ≤ 200μm.

14. The preparation method according to claim 1, wherein The polygon width of the polygon column is e, and 1μm ≤ e ≤ 5μm.

15. A foam structure, characterized in that, The foam structure is prepared by the preparation method according to any one of claims 1 - 14.

16. A display module, characterized in that, Comprising a display panel and a foam layer; The foam layer is located on the backlight side of the display panel; The foam layer includes at least one sub - foam layer; The sub-foam layer includes a plurality of foam structures, and the foam structure includes the foam structure described in claim 15.

17. The display module according to claim 16, wherein the thickness of the foam layer is H4, and 100 μm ≤ H4 ≤ 200 μm.

18. The display module according to claim 16, wherein the shape of the foam structure includes a regular hexagonal prism.

19. The display module according to claim 18, wherein in the sub-foam layer, the regular hexagonal face of the foam structure is parallel to the thickness direction of the sub-foam layer.

20. The display module according to claim 18, wherein in the sub-foam layer, the regular hexagonal face of the foam structure is perpendicular to the thickness direction of the sub-foam layer.

21. The display module according to claim 16, wherein the foam structure of at least one layer of the sub-foam layer includes cellulose fibers.

22. The display module according to claim 16, wherein at least one layer of the sub-foam layer includes at least one first sub-foam layer; the foam structure of the first sub-foam layer includes conductive particles.

23. The display module according to claim 22, wherein the display panel includes a display section; the display module further includes a driving chip, the driving chip is electrically connected to the display panel, and the driving chip is located on a side of the foam layer away from the display section; at least one layer of the sub-foam layer includes at least one second sub-foam layer; the second sub-foam layer is an insulating layer; the first sub-foam layer is located on a side of the second sub-foam layer close to the driving chip.

24. A display device, characterized in that, A display module including any one of claims 16-23.

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