Composite support layer, flexible screen module and manufacturing method of composite support layer

Abstract

The present application relates to flexible screen body technology, and in particular to a composite support layer, a flexible screen module, and a manufacturing method of the composite support layer. The composite support layer comprises a mixed foil, a buffer adhesive material, and a first adhesive layer for bonding the mixed foil and the buffer adhesive material. The mixed foil comprises a first metal foil and a second metal foil, and the first metal foil is spliced around the four peripheral edges of the second metal foil. The bending performance of the first metal foil is better than that of the second metal foil, and the tensile strength of the second metal foil is greater than that of the first metal foil. In some embodiments, the first metal foil is a copper foil, and the second metal foil is an aluminum foil. The present application can solve the technical problem that the tensile force of the FPC is transmitted to the flexible screen body, causing physical indentation of the screen body, during the process of detecting the lit flexible screen body.

Description

TECHNICAL FIELD

[0001] The present application relates to flexible screen body technology, in particular to a composite support layer, a flexible screen module and a manufacturing method of the composite support layer. BACKGROUND

[0002] Most of the current flexible screens choose flexible substrates with bendable performance. In order to ensure the reliability of the flexible substrate, the flexible substrate is packaged by using a polymer cover plate in combination with a special film during production, which forms part of the flexible screen module and enables the screen to maintain bending ability and folding characteristics.

[0003] As shown in Figure 1 , the support film 4 and the composite foam 1 (the foam and the copper foil are usually compounded together through a first adhesive layer, which is called a composite foam) of the current flexible screen module in the industry are designed with full-face adhesive, and the flexible screen body 5 is laminated and adhered with the support film 4 and the composite foam 1. In the production process, the flexible circuit board 2 (Flexible Printed Circuit, FPC for short) needs to be attached and fixed on the copper foil using double-sided adhesive, and the double-sided adhesive forms a multilayer second adhesive layer 3. After the FPC is attached to the copper foil, the flexible screen module needs to be plugged in and out during the subsequent manufacturing process to light up the flexible screen body for detection. During the plugging process, the FPC will be pulled, and the pulling force of the FPC will be transmitted to the composite foam through the double-sided adhesive. Since the copper foil in the composite foam has weak tensile strength and is prone to deformation, the concentrated pulling force at the deformation site will eventually be transmitted to the flexible screen body through the double-sided adhesive. Based on the physical characteristics of the flexible screen body, the flexible screen body is prone to physical indentation after being subjected to the pulling force, as shown in Figure 2 、 Figure 3 , and the severity of the indentation is related to the pulling force of the FPC and the concentration of the pulling force.

[0004] Some manufacturers in the industry may replace the copper foil with an alloy material having higher tensile strength to improve the strength of the foil layer, but due to the limitation of physical characteristics, the bending performance is not as good as that of the copper foil, which may result in a less effective curved bending process for the subsequent flexible screen module compared to the module using the copper foil. SUMMARY

[0005] The composite support layer provided by the embodiments of the present application is composed of a mixed foil and a buffer adhesive material, wherein a metal material with good bending performance is used at the edge of the mixed foil, and a metal material with high tensile strength is used in the middle of the mixed foil, thereby solving the technical problem that the existing flexible screen module is locally pulled up and appears physical indentation during the process of plugging in and out the FPC for lighting up the flexible screen body for detection due to the insufficient tensile strength of the copper foil.

[0006] The embodiment of the present application also provides a flexible screen module, which is provided with the composite support layer.

[0007] The embodiment of the present application also provides a manufacturing method of the composite support layer, which is used for producing and processing the composite support layer.

[0008] The composite support layer provided by the embodiment of the present application comprises a mixed foil, a buffer adhesive material, and a first adhesive layer for bonding the mixed foil and the buffer adhesive material.

[0009] The mixed foil comprises a first metal foil and a second metal foil, and the first metal foil is spliced around the four edges of the second metal foil.

[0010] In some embodiments, the first metal foil is a copper foil, and the second metal foil is an aluminum foil.

[0011] In a further preferred embodiment, the edges of the first metal foil and the edges of the second metal foil are matched with inclined surfaces at the splicing position of the first metal foil and the second metal foil.

[0012] In a further preferred embodiment, the edges of the first metal foil and the edges of the second metal foil are provided with interlocking protrusions at the splicing position of the first metal foil and the second metal foil.

[0013] In a further preferred embodiment, the first adhesive layer is arranged around the edges of the mixed foil and located on the position of the first metal foil.

[0014] In a further preferred embodiment, the composite support layer is used for supporting a flexible screen module, wherein the flexible screen module comprises a flexible circuit board; and the tensile strength of the second metal foil is greater than the tensile force acting on the mixed foil when the flexible circuit board in the flexible screen module is pulled and inserted.

[0015] The flexible screen module provided by the embodiment of the present application comprises the composite support layer provided by the embodiment of the present application, a flexible circuit board, a support film, and a flexible screen body.

[0016] The support film is bonded to the back of the flexible screen body through a second adhesive layer; the composite support layer is located on the side of the support film away from the flexible screen body, and the composite support layer and the support film are bonded through the second adhesive layer; the flexible circuit board is located on the side of the composite support layer away from the support film, and the flexible circuit board and the composite support layer are bonded through the second adhesive layer.

[0017] Preferably, the flexible screen body comprises a bending area and a non-bending area, wherein the orthographic projection area of the bending area on the composite support layer is less than or equal to the area of the first metal foil; and the orthographic projection area of the non-bending area on the composite support layer is greater than or equal to the area of the second metal foil.

[0018] In a further preferred embodiment, the second adhesive layer between the flexible circuit board and the hybrid foil is arranged at the position of the second metal foil of the hybrid foil.

[0019] The manufacturing method of the composite support layer provided by the embodiments of the present application comprises the following steps:

[0020] S1. rolling the first metal foil into a first metal foil;

[0021] S2. performing hole opening on the first metal foil;

[0022] S3. performing sheet processing on the second metal foil according to the shape corresponding to the hole opening of the first metal foil;

[0023] S4. placing the sheet-processed second metal foil according to the hole opening position of the first metal foil;

[0024] S5. splicing the first metal foil and the second metal foil to obtain a composite blank;

[0025] S6. performing foil rolling on the composite blank to manufacture a hybrid foil;

[0026] S7. bonding the hybrid foil with the buffer adhesive material to manufacture a composite support layer;

[0027] Preferably, the bending performance of the first metal foil is better than the bending performance of the second metal foil, and the tensile strength of the second metal foil is greater than the tensile strength of the first metal foil.

[0028] Preferably, the edge of the hole opening position of the first metal foil is provided with a protrusion for engaging with the edge of the second metal foil, and the protrusion is in the shape of a sawtooth, a triangle, a pattern or a wave.

[0029] Compared with the prior art, the composite support layer, the flexible screen module and the manufacturing method of the composite support layer provided by the embodiments of the present application use two materials to manufacture a hybrid foil to replace the traditional copper foil, the edge of the hybrid foil uses copper material and has good toughness, which is a commonly used bending material for the flexible display module at present; the middle of the hybrid foil is a metal material with high tensile strength, and the tensile strength is greater than the pulling force of the FPC, so that the hybrid foil will not be deformed, and the flexible screen body can be prevented from being pulled up locally. In addition, the edge of the hybrid foil can also be provided with an adhesive, which can decompose the pulling force of the FPC applied to the front surface of the hybrid foil to the edge position of the hybrid foil, so as to avoid the pulling force of the FPC being concentrated and transmitted to the middle position of the flexible screen body, and further prevent the flexible screen body from being pulled up locally. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0031] Figure 1 is a schematic diagram of the flexible screen module in the prior art before and after the FPC is pulled;

[0032] Figure 2 is a schematic diagram of the deformed part of the module when the FPC is pulled in the prior art flexible screen module;

[0033] Figure 3 is a partial enlarged view of the copper foil A part in the prior art flexible screen module when the FPC is pulled;

[0034] Figure 4 is a structural schematic diagram of the composite support layer provided by an embodiment of the present application;

[0035] Figure 5 is a splicing structure schematic diagram of the mixed foil in the composite support layer provided by an embodiment of the present application;

[0036] Figure 6 is a top view of the composite support layer provided by an embodiment of the present application;

[0037] Figure 7 is a bottom view of the composite support layer provided by an embodiment of the present application;

[0038] Figure 8 is a structural schematic diagram of the screen module with the composite support layer in the pulled state provided by an embodiment of the present application;

[0039] Figure 9 is a schematic diagram of the second metal foil hollowing in the composite support manufacturing method provided by an embodiment of the present application.

[0040] BRIEF DESCRIPTION OF DRAWINGS: 1, composite foam, 11, mixed foil, 111, first metal foil, 112, second metal foil, 12, first adhesive layer, 13, foam, 2, FPC, 3, second adhesive layer, 4, support film, 5, flexible screen body, 6, copper foil. DETAILED DESCRIPTION

[0041] The features and exemplary embodiments of the various aspects of the present application will be described in detail below with reference to the drawings. To make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, but not to limit the present application. The present application can be implemented without some of the specific details by those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0042] It should be noted that, in this paper, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0043] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The embodiments will be described in detail below with reference to the drawings.

[0044] Embodiment 1

[0045] The present embodiment provides a composite support layer capable of improving film printing of a flexible screen body. In the present embodiment, the composite support layer comprises a mixed foil and a buffer adhesive material, wherein the buffer adhesive material is a foam, and thus the composite support layer is also called a composite foam. The foam is a commonly used material for the flexible screen module at present, and has a certain deformation buffer performance, which can bear the buffer stress for the flexible screen module.

[0046] More specifically, as shown in Figure 4 The composite foam 1 capable of improving film printing of a flexible screen body in the present embodiment comprises a mixed foil 11, a foam 13, and a first adhesive layer 12 for bonding the mixed foil 11 and the foam 13. It should be noted that the first adhesive layer in the present embodiment is a double-sided adhesive, and in actual application, the first adhesive layer can also be a single-sided grid adhesive or a double-sided grid adhesive.

[0047] In the embodiment, the mixed foil comprises a first metal foil 111 and a second metal foil 112, the first metal foil constitutes the four peripheral edges of the mixed foil, the second metal foil constitutes the body of the mixed foil, and the first metal foil is spliced to the four peripheral edges of the second metal foil to form the mixed foil; preferably, at the splicing position, the edges of the first metal foil 111 and the edges of the second metal foil 112 are matching inclined surfaces, and the matching inclined surfaces are provided with interlocking serrations, triangles, patterns, or waves, etc., as shown in Figure 5 The mixed foil is spliced more firmly. Further preferably, the first metal foil and the second metal foil are welded and then rolled to form the mixed foil. The first metal foil is a metal with better bending performance than the second metal foil, and in the embodiment, a copper foil is used because the copper foil has better bending performance and is a commonly used supporting material in the curved bending process of the flexible display module; the second metal foil is a metal with high tensile strength, and the tensile strength of the second metal foil is greater than the preset tensile force, that is, greater than the tensile force acting on the second metal foil when the FPC is pulled out. In the embodiment, the second metal foil preferably uses a high-strength aluminum foil, and the tensile strength of the high-strength aluminum foil is greater than that of the first metal foil. According to the physical properties of the material, the tensile strength of the high-strength aluminum is about 500 MPa, which is twice that of the ordinary copper foil. The above mixed foil design can make the mixed foil have high tensile strength in the center and good bending performance at the edge position, which is more advantageous than the foil layer scheme using an alloy material as a whole in the prior art.

[0048] Further preferably, the first adhesive layer in the composite supporting layer is only arranged at the four peripheral edges of the mixed foil and located at the position of the first metal foil (i.e., the copper foil), as shown in Figure 4 Figure 6 Figure 7 The above arrangement of the first adhesive layer can decompose the tensile force of the FPC to the edge of the mixed foil, and then transmit the decomposed tensile force downward through the buffer adhesive material (i.e., the foam), thereby avoiding the final concentration of the tensile force in the middle position of the flexible screen body. It should be noted that the adhesive force of the first adhesive layer is greater than the pulling force of the FPC, so that the mixed foil will not be separated from the foam due to the reduction of the area of the adhesive layer.

[0049] Embodiment 2

[0050] The flexible screen module provided in the embodiment comprises the composite supporting layer provided in Embodiment 1.

[0051] As shown in Figure 8 ​​As shown, the flexible screen module of the embodiment includes a composite foam 1 (i.e., a composite support layer), a flexible circuit board (FPC) 2, a support film 4, and a flexible screen body 5. The back of the flexible screen body is a non-light-emitting surface. The support film 4 is adhered to the back of the flexible screen body through a second adhesive layer. The composite foam 1 is located on the side of the support film away from the flexible screen body, and the composite foam and the support film are adhered through a second adhesive layer. The flexible circuit board 2 is located on the side of the composite foam away from the support film, and the flexible circuit board and the composite foam are adhered through a second adhesive layer. The support film is a commonly used component of the flexible screen module, which can maintain the bending ability and folding characteristics of the screen. The flexible circuit board FPC is also a commonly used component of the flexible screen module.

[0052] In a preferred embodiment, the flexible screen body includes a bending area and a non-bending area. The orthographic projection area of the bending area on the composite support layer is less than or equal to the area of the first metal foil in the mixed foil of the composite foam. The orthographic projection area of the non-bending area on the composite support layer is greater than or equal to the area of the second metal foil in the mixed foil of the composite foam. The first metal foil is arranged in the bending area corresponding to the edge of the flexible screen body. The second metal foil is arranged in the non-bending area of the flexible screen body.

[0053] In the embodiment, the second adhesive layer between the flexible circuit board and the mixed foil, and the second adhesive layer between the support film and the buffer adhesive material (i.e., the foam) can be implemented by double-sided adhesive tape.

[0054] In the embodiment, the flexible circuit board FPC and the composite support layer are adhered through the edge position of the mixed foil, i.e., the second adhesive layer between the flexible circuit board and the mixed foil is arranged at the position of the second metal foil of the mixed foil, so that the tensile force transmitted by the flexible circuit board FPC to the composite support layer acts on the second metal foil with greater tensile strength, further avoiding the flexible screen body from being partially pulled up.

[0055] Embodiment 3

[0056] Based on the same inventive concept as the composite support layer provided in Embodiment 1, the present application also provides a manufacturing method of the composite support layer for improving the film printing of the flexible screen body. It should be noted that the manufacturing method takes the combination of copper foil and aluminum foil as an example. When the aluminum foil is replaced by other metal foil combinations, similar mixed foils can be obtained by adjusting the common welding process parameters and rolling process parameters. The adjustment of the process parameters is based on the prior art, and those skilled in the art can operate according to the physical properties of the materials.

[0057] The manufacturing method of the composite support layer of the embodiment includes the following steps:

[0058] S1. Roll the thick copper foil to a thickness of 0.15 mm, and make a copper foil 6, as shown in Figure 9 .

[0059] S2. Take a copper foil, and make holes on the copper foil according to the size requirement. The operation of making holes can be completed by punching or laser cutting.

[0060] S3. Slice the 0.15mm aluminum foil according to the shape corresponding to the hole of the copper foil, and the operation of slicing can be completed by punching or laser cutting.

[0061] It is worth noting that the size of the slicing is in a tolerance fit with the size of the hollowed-out position in the copper foil; the tolerance fit can be an interference fit, that is, the size of the aluminum foil after slicing is greater than or equal to the size of the hollowed-out position in the copper foil, and the relative difference is between 0mm-0.5mm; the tolerance fit can also be a clearance fit, that is, the size of the aluminum foil after slicing is less than or equal to the size of the hollowed-out position in the copper foil, and the relative difference is between -0.1mm-0mm; after the subsequent hot melting, the two metal layers of the aluminum foil and the copper foil can be fused together, or they can be integrated by foil bonding, forming a lap joint or a splice structure.

[0062] S4. Place the aluminum foil after slicing according to the hole position of the copper foil, and the filling process can be completed by a conventional positioning fixture or manual operation. If a positioning fixture is used, the accurate positioning of the aluminum foil can optimize the subsequent laser welding effect, but the relative cost is higher.

[0063] S5. Use laser welding process to weld and splice the copper foil and the aluminum foil to obtain a composite plate blank.

[0064] S6. Foil bonding is performed on the composite plate blank, and the foil bonding process includes multiple rolling, and finally a mixed foil with a thickness of 4 to 100 microns is manufactured, and the specific thickness is determined according to the requirement of the flexible screen module.

[0065] S7. The mixed foil is bonded with a buffer bonding material to manufacture a composite support layer. In this embodiment, the buffer bonding material is foam, and therefore the composite foam is manufactured in this step.

[0066] S8. Finally, the composite support layer is punched according to the actual required size.

[0067] It is worth noting that after step S7, the mixed foil can be annealed to effectively ensure the performance of the mixed foil; and then the annealed mixed foil is flattened under a flattening machine to improve the flatness of the mixed foil.

[0068] wherein the bending performance of the first metal foil is better than the bending performance of the second metal foil, and the tensile strength of the second metal foil is greater than the tensile strength of the first metal foil;

[0069] In the preferred embodiment, the edge of the opening position of the first metal foil is provided with a protrusion for engaging with the edge of the second metal foil, which is in the shape of a sawtooth, a triangle, a pattern or a wave, etc. The above processing shape is used to ensure that the aluminum foil and the copper foil are closely engaged after the subsequent aluminum foil and copper foil welding and re-foil binding process, and cracks are not easily generated.

[0070] It should be noted that the present application is not limited to the specific configurations and processes described above and shown in the drawings. For the sake of brevity, detailed descriptions of well-known methods are omitted. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between steps, after understanding the spirit of the present application.

[0071] It should also be noted that the exemplary embodiments mentioned in the present application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiments, or in an order different from the embodiments, or several steps can be performed simultaneously.

[0072] The above describes the aspects of the present application with reference to the flowcharts and / or block diagrams of the methods, devices and computer program products according to the embodiments of the present application. It should be understood that each block in the flowchart and / or block diagram, and the combination of blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the functions / actions specified in one or more blocks of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It should also be understood that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can also be implemented by special hardware that performs the specified functions or actions, or can be implemented by a combination of special hardware and computer instructions.

[0073] The above is only a specific embodiment of the present application, and those skilled in the art can clearly understand that, for the sake of convenience and brevity of description, the specific working process of the above-described system, module and unit can refer to the corresponding process in the foregoing method embodiments, which will not be described here. It should be understood that the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A composite support layer characterized in that, The composite support layer comprises a mixed foil, a buffer adhesive material, and a first adhesive layer for bonding the mixed foil and the buffer adhesive material; The mixed foil comprises a first metal foil and a second metal foil, and the first metal foil is spliced around the four edges of the second metal foil; The bending performance of the first metal foil is better than that of the second metal foil, and the tensile strength of the second metal foil is greater than that of the first metal foil; The composite support layer is used for supporting a flexible screen module, wherein the flexible screen module comprises a flexible circuit board; the tensile strength of the second metal foil is greater than the tensile force acting on the mixed foil when the flexible circuit board in the flexible screen module is pulled and plugged; The first adhesive layer is only arranged on the four edges of the mixed foil and is located on the first metal foil, and the orthographic projection of the first adhesive layer on the mixed foil is located in the first metal foil; the adhesive force of the first adhesive layer is greater than the pulling force when the flexible circuit board in the flexible screen module is pulled and plugged; The buffer adhesive material is foam, and there is a gap between the foam and the second metal foil.

2. The composite support layer of claim 1, wherein, At the splicing position of the first metal foil and the second metal foil, the edge of the first metal foil and the edge of the second metal foil are matching inclined surfaces.

3. The composite support layer according to claim 1 or 2, characterized in that At the splicing position of the first metal foil and the second metal foil, a protrusion is arranged on the edge of the first metal foil and the edge of the second metal foil.

4. The composite support layer of claim 3, wherein, The protrusion is sawtooth-shaped, triangular, patterned or wavy.

5. The composite support layer of claim 1, wherein, The first metal foil is a copper foil, and the second metal foil is an aluminum foil.

6. A flexible screen module, characterized in that, The composite support layer comprises a mixed foil, a buffer adhesive material, and a first adhesive layer for bonding the mixed foil and the buffer adhesive material; The composite support layer is used for supporting a flexible screen module, wherein the flexible screen module comprises a flexible circuit board; the tensile strength of the second metal foil is greater than the tensile force acting on the mixed foil when the flexible circuit board in the flexible screen module is pulled and plugged; 7. The flexible screen module of claim 6, wherein, The flexible screen body comprises a bending area and a non-bending area, wherein the orthographic projection area of the bending area on the composite support layer is less than or equal to the area of the first metal foil; and the orthographic projection area of the non-bending area on the composite support layer is greater than or equal to the area of the second metal foil. 8.The flexible screen module of claim 6, wherein, The second adhesive layer between the flexible circuit board and the mixed foil is arranged at the position of the second metal foil of the mixed foil.

9. A method of manufacturing the composite support layer of any one of claims 1-5, wherein, The manufacturing method comprises the following steps: S1. rolling a first metal foil from a first metal strip; S2. performing hole opening on the first metal foil; S3. performing sheet processing on a second metal foil according to the shape corresponding to the hole opening of the first metal foil; S4. placing the sheet-processed second metal foil according to the hole opening position of the first metal foil; S5. splicing the first metal foil and the second metal foil to obtain a composite blank; S6. rolling the composite blank to obtain a mixed foil; S7. bonding the mixed foil and the buffer adhesive material to obtain a composite support layer; The bending performance of the first metal foil is better than that of the second metal foil, and the tensile strength of the second metal foil is greater than that of the first metal foil; The composite support layer is used for supporting a flexible screen module, wherein the flexible screen module comprises a flexible circuit board; the tensile strength of the second metal foil is greater than the tensile force acting on the mixed foil when the flexible circuit board in the flexible screen module is pulled and plugged.

10. The manufacturing method according to claim 9, wherein The edge of the opening position of the first metal foil is provided with a protrusion for engaging with the edge of the second metal foil, and the protrusion is in the shape of a sawtooth, a triangle, a pattern or a wave.

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