Screen laminated structure, display module and electronic equipment

Abstract

The invention relates to a screen cover plate, a folding screen module and electronic equipment, the screen cover plate is used for covering a flexible screen, the screen cover plate comprises a buffer layer, a first film layer and a second film layer, and the buffer layer absorbs impact stress through elastic deformation; the first film layer covers the side, away from the flexible screen, of the buffer layer, the modulus of the first film layer is larger than that of the buffer layer, and the first film layer and the buffer layer are bonded through a first adhesive layer; the second film layer covers the side, close to the flexible screen, of the buffer layer, the modulus of the second film layer is larger than that of the buffer layer, and the second film layer and the buffer layer are bonded through a second adhesive layer. The impact resistance of the folding screen module can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a screen stacking structure, a display module and an electronic equipment. Background Art

[0002] The new mobile phone form factor of flexible folding screen has brought users a brand new user experience. However, due to the need to use a large amount of flexible polymer materials in the laminated design of the folding screen module (especially the design of the screen cover), its rigidity and strength are far inferior to the inorganic materials (such as cover glass) used in straight-screen and curved-screen mobile phones. For example, in Huawei's first-generation external folding display module, the cover uses an 80μm thick transparent polyimide film. Compared with the 500μm cover glass in the straight-screen phone, its rigidity is less than 1 / 2000 of the cover glass of the straight-screen phone, resulting in its weak ability to resist impact and deformation. The ensuing reliability problem of the folding screen module has greatly reduced the user experience. Summary of the invention

[0003] The present application provides a screen cover, a folding screen module and an electronic device to improve the impact resistance of the folding screen module.

[0004] A first aspect of the present application provides a screen cover for covering a flexible screen, the screen cover comprising:

[0005] A buffer layer, wherein the buffer layer absorbs impact stress through elastic deformation;

[0006] A first film layer, covering a side of the buffer layer away from the flexible screen, the modulus of the first film layer is greater than the modulus of the buffer layer, and the first film layer and the buffer layer are bonded by a first adhesive layer;

[0007] The second film layer covers a side of the buffer layer close to the flexible screen, the modulus of the second film layer is greater than the modulus of the buffer layer, and the second film layer is bonded to the buffer layer through a second adhesive layer.

[0008] The above-mentioned screen cover is used to cover the flexible screen and can be folded together with the flexible screen. The screen cover includes a buffer layer, a first film layer and a second film layer; the buffer layer absorbs impact stress through elastic deformation, thereby reducing the tensile strain inside the flexible screen; the first film layer covers the side of the buffer layer away from the flexible screen, that is, the first film layer forms the outer surface of the screen cover, and the modulus of the first film layer is greater than the modulus of the buffer layer to increase the strength of the outer surface of the screen cover and prevent the outer surface of the screen cover from being damaged by scratches, etc. The first film layer and the buffer layer are bonded by a first adhesive layer, and the deformation of the first film layer and the buffer layer is separated from each other by setting the first adhesive layer. One adhesive layer can produce shear deformation to alleviate the transmission of tensile strain on the lower surface of the first film layer to the buffer layer; the second film layer covers the side of the buffer layer close to the flexible screen, that is, the second film layer is used to connect the surface of the flexible screen, and the modulus of the second film layer is greater than that of the buffer layer to increase the strength of the inner surface of the screen cover to prevent the inner surface of the screen cover from undergoing large deformation, thereby causing impact damage to the flexible screen. The second film layer and the buffer layer are bonded to each other through the second adhesive layer, and the deformation of the second film layer and the buffer layer are separated from each other by the provision of the second adhesive layer. The second adhesive layer can produce shear deformation to alleviate the transmission of tensile strain on the lower surface of the buffer layer to the second film layer.

[0009] Optionally, the thickness of the second film layer is 25 μm to 150 μm, which can not only make the screen cover have better impact resistance, but also ensure that the screen cover has higher folding performance.

[0010] Optionally, the thickness of the second film layer is 25 μm to 75 μm, which can not only make the screen cover have better impact resistance, but also ensure that the screen cover has excellent folding performance.

[0011] Optionally, the modulus of the second film layer is not less than 1 GPa to ensure that the second film layer does not undergo significant deformation after the screen cover is impacted.

[0012] Optionally, the material of the second film layer is transparent polyimide, polyester, epoxy resin or ultra-thin glass.

[0013] Optionally, the second film layer and the first film layer are made of the same material, which simplifies the processing technology of the screen cover and reduces the production cost of the screen cover.

[0014] The second aspect of the present application provides a folding screen module, which includes:

[0015] Flexible screen;

[0016] A screen cover plate covers the surface of the flexible screen, and the screen cover plate is any one of the above-mentioned screen cover plates.

[0017] The third aspect of the present application provides a folding screen module, which includes:

[0018] Flexible screen;

[0019] A screen cover plate, covering the surface of the flexible screen, the screen cover plate comprising:

[0020] A buffer layer, wherein the buffer layer absorbs impact stress through elastic deformation;

[0021] A first film layer, covering a side of the buffer layer away from the flexible screen, the modulus of the first film layer is greater than the modulus of the buffer layer, and the first film layer and the buffer layer are bonded by a first adhesive layer;

[0022] The buffer layer is bonded to the surface of the flexible screen via a third adhesive layer, and the thickness of the third adhesive layer is not less than half of the thickness of the buffer layer.

[0023] The above-mentioned folding screen module includes a flexible screen and a screen cover, the screen cover covers the surface of the flexible screen, and the screen cover includes a buffer layer and a first film layer; the buffer layer absorbs impact stress through elastic deformation, thereby reducing the tensile strain inside the flexible screen; the first film layer covers the side of the buffer layer away from the flexible screen, that is, the first film layer forms the outer surface of the screen cover, and the modulus of the first film layer is greater than the modulus of the buffer layer, so as to increase the strength of the outer surface of the screen cover and prevent the outer surface of the screen cover from being damaged such as scratches. The first film layer and the buffer layer are bonded by a first adhesive layer, and the deformation of the first film layer and the buffer layer are separated from each other by setting the first adhesive layer, so as to avoid the strain of the buffer layer being transmitted to the first film layer; the buffer layer is bonded to the surface of the flexible screen through a third adhesive layer, and the thickness of the third adhesive layer is not less than half of the thickness of the buffer layer. The third adhesive layer with a larger thickness plays an isolation role between the buffer layer and the flexible screen, thereby alleviating the transmission of the strain of the buffer layer to the flexible screen.

[0024] Optionally, the thickness of the buffer layer is not greater than 50 μm, and the thickness of the third adhesive layer is 15 μm to 75 μm.

[0025] Optionally, the buffer layer has a thickness of 50 μm to 100 μm, and the third adhesive layer has a thickness of 25 μm to 100 μm.

[0026] Optionally, the buffer layer has a thickness of 100 μm to 150 μm, and the third adhesive layer has a thickness of 50 μm to 125 μm.

[0027] Optionally, the buffer layer has a thickness of 150 μm to 200 μm, and the third adhesive layer has a thickness of 50 μm to 150 μm.

[0028] Optionally, the thickness of the buffer layer is not less than 200 μm, and the thickness of the third adhesive layer is not less than 75 μm.

[0029] A fourth aspect of the present application provides an electronic device comprising any one of the above-mentioned folding screen modules.

[0030] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of a folding screen module in the prior art;

[0032] Figure 2 It is a structural schematic diagram of another folding screen module in the prior art;

[0033] Figure 3 This is a schematic diagram of a falling ball impact test;

[0034] Figure 4 A schematic diagram of the structure of the first folding screen module provided in an embodiment of the present application;

[0035] Figure 5 This is a state diagram of the folding screen module being deformed in an impact scenario;

[0036] Figure 6 for Figure 5 Stress analysis of lateral deformation occurring in the process;

[0037] Figure 7 for Figure 5 Schematic diagram of the bending deformation that occurs in the

[0038] Figure 8 A schematic diagram of the structure of a second folding screen module provided in an embodiment of the present application;

[0039] Fig. 9 A schematic diagram of the structure of the third folding screen module provided in an embodiment of the present application.

[0040] Reference numerals:

[0041] 01- plane area;

[0042] 02-Bending area;

[0043] 03-Flexible filler;

[0044] 1-Screen cover;

[0045] 11- buffer layer;

[0046] 12- first film layer;

[0047] 13- first adhesive layer;

[0048] 14- second film layer;

[0049] 15- second adhesive layer;

[0050] 16- third adhesive layer;

[0051] 2- Flexible screen;

[0052] 21- Polarizer;

[0053] 22- Panel;

[0054] 3- Support assembly.

[0055] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0056] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0057] In a specific embodiment, the present application is further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0058] An embodiment of the present application provides an electronic device, which includes a folding screen module. The electronic device can be a common mobile terminal such as a mobile phone or a tablet computer, and the electronic device has a folded state and an unfolded state; in the folded state, the folding screen module bends together with the electronic device; in the unfolded state, the folding screen module unfolds into a plane together with the electronic device.

[0059] The folding screen module provided in the embodiment of the present application includes a screen cover 1, a flexible screen 2 and a support component 3. The flexible screen 2 can be an integrated flexible display screen, or a spliced ​​display screen consisting of two rigid screens and a flexible screen located between the two rigid screens; the support component 3 supports the flexible screen 2, and the screen cover 1 covers the side of the flexible screen 2 away from the support component 3, that is, the screen cover 1 is attached to the outer surface of the flexible screen 2, and the screen cover 1 protects the flexible screen 2 and improves the flatness of the surface of the flexible screen 2. The screen cover 1 is light-transmissive, and the image displayed on the flexible screen 2 can be seen through the screen cover 1, and the screen cover 1 can be bent or flattened synchronously with the flexible screen 2 to adapt to the switching of the folding screen module between the unfolded state and the folded state.

[0060] Among them, the screen cover, as the protective layer of the screen, plays the most critical role in the impact resistance of the module. Therefore, the structural optimization of the screen cover is naturally one of the important improvement directions for improving the impact resistance of the folding screen module. Figure 1 and Figure 2The screen cover mainly includes a flat area 01 and a bending area 02. The bending area 02 is located in the center, and the flat area 01 is distributed on both sides of the bending area 02; the flat area 01 does not need to bend and deform, that is, the flat area 01 always maintains a flat state; the bending area 02 is bent and flattened, so that the screen cover can be folded and unfolded together with the flexible screen.

[0061] like Figure 1 As shown, the plane area 01 uses a relatively thick cover glass (100μm to 200μm), and the thickness of the bending area 02 is less than that of the plane area 01, that is, the bending area 02 is locally thinned, and the locally thinned part is filled with a flexible filler 03, which is a low modulus polymer material. In order to achieve the bending characteristics of the glass, the thickness of the general glass needs to be controlled within 70μm, that is, the thickness of the bending area 02 does not exceed 70μm; according to the existing local thinning process, the thick glass used is generally 100μm to 200μm, that is, the thickness of the plane area 01 is 100μm to 200μm, which is still much different from the 500μm thick cover glass of the straight-screen machine in terms of stiffness. Therefore, the plane area 01 cannot guarantee the same impact resistance as the straight-screen machine, and the bending area 02 has a weaker impact resistance due to the thinner glass. Therefore, the screen cover of this structure is difficult to meet the impact resistance requirements.

[0062] like Figure 2 As shown, the flat area 01 uses a thicker cover glass (100μm to 500μm), and the bending area 02 is provided with a hole area, that is, the bending area 02 is partially etched (it can be etched into a through hole or a blind hole), and the etched hole area is filled with a flexible filler 03, and the flexible filler 03 is a low modulus polymer material. Since the solution performs local etching in the bending area 02, there is a local step difference in the hole area position in the bending area 02, which will generate a stress concentration point on the screen when an impact occurs, resulting in poor impact resistance reliability of the bending area.

[0063] The screen cover plates of the above two structures are not reliable enough in impact resistance, which makes the folding screen module prone to bright spots. According to the second failure criterion of brittle materials, the main reason for the bright spots is that when the folding screen module is impacted by the outside world, the thin film transistor (TFT) in the panel structure is subjected to impact compressive stress, which causes local bending deformation, causing the tensile strain of the TFT to exceed its limit strain, resulting in short circuit or open circuit in the relevant area, resulting in display abnormalities such as bright spots. Figure 3The impact resistance of the folding screen module can be evaluated through a drop ball impact test, that is, a steel ball of a specified weight (for example, 32g) is dropped freely from a specified drop height onto the product to impact the product, and then the product appearance and various performances are checked; under the current laminated structure scheme, the folding screen module performs extremely poorly in the drop ball impact test. For example, the current Mate Xs module has a drop ball impact resistance of only 4.5cm in the flat area and only 2.8cm in the bending area, which is completely unable to meet the basic requirements of users for anti-impact performance during daily use.

[0064] In addition, both of the above structures require filling flexible filler 03 on the cover glass. If optical traces are to be left, the refractive index between the glass and the polymer material must be highly matched (generally, the refractive indices of the two materials must remain consistent to 6 decimal places). However, since the molecular weight of the polymer material is generally in the form of a normal distribution, precise control of the refractive index cannot be achieved. Therefore, the optical requirement of no light and shadow cannot be achieved, which affects the appearance of the folding screen module.

[0065] The folding screen module provided in the first embodiment of the present application can be referred to Figure 4 , which includes a screen cover 1, a flexible screen 2 and a supporting component 3. The flexible screen 2 includes a polarizer 21 and a panel 22. The polarizer 21 (i.e., Polarizer, abbreviated as POL) is arranged on the side of the panel 22 facing the screen cover 1, and a TFT is arranged in the panel 22; the screen cover 1 is used to cover the flexible screen 2 and can be folded together with the flexible screen 2. The screen cover 1 is bonded to the surface of the flexible screen 2 through a third adhesive layer 16 (such as OCA); the screen cover 1 includes at least two layers, and each layer is stacked in sequence to form a laminated structure design, so that the screen cover 1 forms a continuous surface structure, thereby improving the appearance of the folding screen module; the screen cover 1 includes at least one buffer layer 11. For example, the screen cover 1 may include a buffer layer 11 and a first film layer 12. The first film layer 12 covers a side of the buffer layer 11 away from the flexible screen 2. side, that is, the first film layer 12 forms the outer surface of the screen cover 1; the buffer layer 11 selects a transparent buffer layer 11 with a suitable modulus, that is, the buffer layer 11 absorbs impact stress through elastic deformation, thereby protecting the screen and greatly improving the impact resistance of the module stack; the modulus of the first film layer 12 is greater than the modulus of the buffer layer 11, so as to increase the strength of the outer surface of the screen cover 1 and prevent the outer surface of the screen cover 1 from being damaged by scratches, etc. The first film layer 12 and the buffer layer 11 are bonded by the first adhesive layer 13. The deformation of the first film layer 12 and the buffer layer 11 are separated from each other by the provision of the first adhesive layer 13. The first adhesive layer 13 can produce shear deformation to alleviate the transmission of the tensile strain on the lower surface of the first film layer 12 to the buffer layer 11.

[0066] Among them, the buffer layer 11 is made of a transparent material with a modulus of 10Mpa to 200Mpa. For example, the modulus of the buffer layer 11 can be 10Mpa, 30Mpa, 50Mpa, 60Mpa, 80Mpa, 100Mpa, 110Mpa, 130Mpa, 150Mpa, 160Mpa, 180Mpa or 200Mpa, etc. In an optional embodiment, the buffer layer 11 is made of polyurethane (ThermoplasticPU, abbreviated as TPU) material.

[0067] The first film layer 12 is made of a transparent material with a high modulus. The modulus of the first film layer 12 is much greater than that of the buffer layer 11. The first film layer 12 needs to be bendable and have a high surface strength. For example, the first film layer 12 can be made of a polyester (Polyethylene terephthalate, abbreviated as PET) material. The first adhesive layer 13 can be made of an optical clear adhesive (OCA). The modulus of the first adhesive layer 13 is much smaller than that of the buffer layer 11. When the buffer layer 11 is deformed by impact, shear deformation can occur in the first adhesive layer 13 to store energy, so that the buffer layer 11 and the first film layer 12 can form their own neutral layers to prevent the deformation of the buffer layer 11 from affecting the first film layer 12.

[0068] In order to illustrate the impact resistance of the screen cover 1 provided in this embodiment, a comparative experiment is conducted on the impact resistance of a common folding screen module and a folding screen module using the screen cover provided in this embodiment. The comparative experimental results are shown in Table 1. The specific experimental method is a falling ball impact test (reference Figure 3 ); The folding screen modules in each group of embodiments have the same parameters except for the structure of the screen cover 1, and the other experimental conditions are also the same. Each experimental group represents a group of sample folding screen modules, and the experimental results are the average values ​​of the experimental results of the sample folding screen modules in the group.

[0069] Table 1

[0070]

[0071] According to the experimental data in Table 1, it can be seen that the control group 1 uses a PET layer without buffering performance, and the module's anti-falling ball impact height is 2 cm; the experimental groups 1 to 3 use a TPU layer with a buffering effect, and the module's anti-falling ball impact heights are 14 cm, 16 cm and 18 cm, respectively; therefore, the screen cover 1 provided in the embodiment of the present application can effectively reduce impact stress and reduce the tensile strain of the TFT layer caused by impact stress by setting a buffer layer 11, thereby improving the impact resistance of the folding screen module, and as the thickness of the buffer layer 11 increases, the impact resistance of the screen cover 1 gradually increases. However, through the comparison of experimental group 1 and experimental group 3, it can be seen that when the thickness of the buffer layer (TPU) increases from 100μm to 200μm, the thickness of the buffer layer doubles, but the impact resistance of the folding screen module has not been improved accordingly. For example, when a 100μm buffer layer is used, the module's resistance to falling ball impact height is 14cm, but when the thickness of the buffer layer is increased from 100μm to 200μm, the module's resistance to falling ball impact height is 18cm, and the resistance to falling ball impact height is only increased by 4cm.

[0072] refer to Figure 5-Figure 7 ,Further analysis shows that in the impact scenario, there are two sources of tensile strain in the TFT layer: one of which is Figure 6 As shown in Figure 1, the TFT layer undergoes lateral deformation under the longitudinal impact compressive stress; the other one is as shown in Figure 1. Figure 7 As shown, tensile strain is generated due to local bending of the laminated structure of the folding screen module during the impact, wherein the dotted line is the neutral layer of the buffer layer 11.

[0073] from Figure 6 It can be seen from the figure that the buffer layer 11 can reduce the longitudinal impact stress and reduce the lateral deformation of the TFT layer under the impact stress, so that the impact resistance of the screen cover 1 can be improved by setting the buffer layer 11; Figure 7 It can be seen that the thickness of the buffer layer 11 gradually increases along the direction indicated by the arrow, and the farther the lower surface of the buffer layer 11 is from the neutral layer of the buffer layer 11, the greater the tensile strain occurring on the lower surface of the buffer layer 11. Since the lower surface of the buffer layer 11 is closer to the panel TFT layer, the tensile strain on the lower surface of the buffer layer 11 will be transmitted to the TFT layer of the panel, resulting in an increase in the tensile strain of the TFT layer of the panel; therefore, the thickening of the buffer layer 11 also results in an increase in the tensile stress on the lower surface of the buffer layer 11. When the buffer layer 11 is closer to the panel, it will be affected by the tensile strain on the lower surface of the buffer layer 11, causing the tensile strain of the TFT layer to increase, so that the increase in the thickness of the buffer layer 11 cannot significantly improve the impact resistance of the screen cover 1.

[0074] The folding screen module provided in the second embodiment of the present application can be referred to Figure 8, which includes a screen cover 1, a flexible screen 2 and a supporting assembly 3. The screen cover 1 covers the surface of the flexible screen 2, and includes a buffer layer 11 and a first film layer 12; the buffer layer 11 absorbs impact stress through elastic deformation, thereby reducing the tensile strain inside the flexible screen 2; the first film layer 12 covers the side of the buffer layer 11 away from the flexible screen 2, that is, the first film layer 12 forms the outer surface of the screen cover 1, and the modulus of the first film layer 12 is greater than the modulus of the buffer layer 11, so as to increase the strength of the outer surface of the screen cover 1 and prevent the outer surface of the screen cover 1 from being scratched or damaged. The first film layer 12 and the buffer layer 11 are connected by a first adhesive layer 13 Bonding: By setting the first adhesive layer 13, the deformation of the first film layer 12 and the buffer layer 11 are separated from each other. The first adhesive layer 13 can produce shear deformation, thereby alleviating the transmission of the tensile strain on the lower surface of the first film layer 12 to the buffer layer 11; the buffer layer 11 is bonded to the surface of the flexible screen 2 through the third adhesive layer 16. The thickness of the third adhesive layer 16 is not less than half the thickness of the buffer layer 11. The third adhesive layer 16 with a larger thickness plays an isolation role between the buffer layer 11 and the flexible screen 2. The third adhesive layer 16 can produce shear deformation, thereby effectively alleviating the transmission of the strain of the buffer layer 11 to the flexible screen 2.

[0075] Specifically, the modulus of the third adhesive layer 16 is much smaller than the modulus of the buffer layer 11. When the thickness of the buffer layer 11 increases, the thickness of the third adhesive layer 16 (such as OCA) on the lower surface of the buffer layer 11 increases synchronously, that is, the thickness of the OCA on the lower surface of the buffer layer 11 must match the thickness of the buffer layer 11. On the one hand, by increasing the thickness of the third adhesive layer 16, the distance between the lower surface of the buffer layer 11 and the flexible screen 2 can be increased, so that the strain of the buffer layer 11 is difficult to transfer to the TFT layer; on the other hand, since the modulus of OCA is generally 10Kpa~100Kpa, which is much lower than the modulus of the buffer layer 11 (10Mpa~200Mpa), when the module is locally bent during the impact process, the OCA can undergo shear deformation, and the strain on the lower surface of the buffer layer 11 is stored in the form of shear strain energy, thereby reducing the downward conduction of the strain. The specific scheme is as follows:

[0076] (1) The thickness of the buffer layer 11 is not greater than 50 μm, and the thickness of the third adhesive layer 16 is 15 μm to 75 μm. That is, when the thickness of the buffer layer 11 is ≤50 μm, the thickness of the OCA is preferably 15 μm to 75 μm. Typically but not restrictively, when the thickness of the buffer layer 11 is 25 μm, the thickness of the OCA is preferably 15 μm to 25 μm, for example, the thickness of the OCA is 15 μm or 25 μm. When the thickness of the buffer layer 11 is 50 μm, the thickness of the OCA is preferably 25 μm to 50 μm, for example, the thickness of the OCA is 25 μm or 50 μm.

[0077] (2) The thickness of the buffer layer 11 is 50 μm to 100 μm, and the thickness of the third adhesive layer 16 is 25 μm to 100 μm. That is, when the thickness of the buffer layer 11 is between 50 μm and 100 μm, the thickness of the OCA is preferably 25 μm to 100 μm. Typically but not restrictively, when the thickness of the buffer layer 11 is 100 μm, the thickness of the OCA is preferably 50 μm to 75 μm, for example, the thickness of the OCA is 50 μm or 75 μm.

[0078] (3) The thickness of the buffer layer 11 is 100 μm to 150 μm, and the thickness of the third adhesive layer 16 is 50 μm to 125 μm. That is, when the thickness of the buffer layer 11 is between 100 μm and 150 μm, the thickness of the OCA is preferably 50 μm to 125 μm. Typically but not restrictively, when the thickness of the buffer layer 11 is 150 μm, the thickness of the OCA is preferably 75 μm to 100 μm, for example, the thickness of the OCA is 75 μm or 100 μm.

[0079] (4) The thickness of the buffer layer 11 is 150 μm to 200 μm, and the thickness of the third adhesive layer 16 is 50 μm to 150 μm. That is, when the thickness of the buffer layer 11 is between 150 and 200 μm, the thickness of the OCA is preferably 50 to 150 μm. Typically but not restrictively, when the thickness of the buffer layer 11 is 175 μm, the thickness of the OCA is preferably 75 μm to 125 μm, for example, the thickness of the OCA is 75 μm, 100 μm or 125 μm.

[0080] (5) The thickness of the buffer layer 11 is not less than 200 μm, and the thickness of the third adhesive layer 16 is not less than 75 μm. That is, when the thickness of the buffer layer 11 is ≥ 200 μm, the thickness of the OCA is preferably ≥ 75 μm.

[0081] In order to illustrate the impact resistance of the screen cover 1 provided in this embodiment, a comparative experiment is conducted on the impact resistance of the folding screen modules with different thicknesses of the third adhesive layer 16. The comparative experimental results are shown in Table 2. The specific experimental method is a falling ball impact test (reference Figure 3 ); The folding screen modules in each group of embodiments have the same parameters except for the structure of the screen cover 1, and the other experimental conditions are also the same. Each experimental group represents a group of sample folding screen modules, and the experimental results are the average values ​​of the experimental results of the sample folding screen modules in the group.

[0082] Table 2

[0083]

[0084]

[0085] It can be seen from the experimental data in Table 2 that by increasing the thickness of the third adhesive layer 16, the impact resistance of the folding screen module can be effectively improved.

[0086] The folding screen module provided in the third embodiment of the present application can be referred to Fig. 9 , which includes a screen cover 1, a flexible screen 2 and a supporting assembly 3. The screen cover 1 is used to cover the flexible screen 2 and can be folded together with the flexible screen 2. The screen cover 1 includes a buffer layer 11, a first film layer 12 and a second film layer 14; the buffer layer 11 absorbs impact stress through elastic deformation, thereby reducing the tensile strain inside the flexible screen 2; the first film layer 12 covers the side of the buffer layer 11 away from the flexible screen 2, that is, the first film layer 12 forms the outer surface of the screen cover 1, and the modulus of the first film layer 12 is greater than the modulus of the buffer layer 11, so as to increase the strength of the outer surface of the screen cover 1 and prevent the outer surface of the screen cover 1 from being damaged by scratches, etc. The first film layer 12 and the buffer layer 11 are bonded by a first adhesive layer 13, and the deformation of the first film layer 12 and the buffer layer 11 are separated from each other by setting the first adhesive layer 13. A glue layer 13 can produce shear deformation to alleviate the transmission of tensile strain on the lower surface of the first film layer 12 to the buffer layer 11; the second film layer 14 covers the side of the buffer layer 11 close to the flexible screen 2, that is, the second film layer 14 is used to connect the surface of the flexible screen 2, and the modulus of the second film layer 14 is greater than that of the buffer layer 11, so as to increase the strength of the inner surface of the screen cover 1 to prevent the inner surface of the screen cover 1 from undergoing large deformation, thereby causing impact damage to the flexible screen 2. The second film layer 14 and the buffer layer 11 are bonded to each other through a second glue layer 15. The second glue layer 15 is arranged to separate the deformation of the second film layer 14 and the buffer layer 11 from each other. The second glue layer 15 can produce shear deformation to alleviate the transmission of tensile strain on the lower surface of the buffer layer 11 to the second film layer 14.

[0087] The second film layer 14 is made of a transparent material with a high modulus. The modulus of the second film layer 14 is much greater than that of the buffer layer 11. The second film layer 14 needs to be bendable and have a high surface strength. The modulus and thickness of the second film layer 14 are controlled to prevent the strain from being transmitted downward. The second adhesive layer 15 can be made of an optical clear adhesive (OCA). The modulus of the first adhesive layer 13 is much smaller than that of the buffer layer 11. When the buffer layer 11 is deformed by impact, shear deformation can occur in the first adhesive layer 13 to store energy, so that the buffer layer 11 and the second film layer 14 can form their own neutral layers, preventing the deformation of the buffer layer 11 from affecting the second film layer 14.

[0088] Furthermore, the thickness of the second film layer 14 is 25μm to 150μm. For example, the thickness of the second film layer 14 can be 25μm, 35μm, 45μm, 55μm, 60μm, 65μm, 75μm, 85μm, 95μm, 100μm, 110μm, 120μm, 130μm, 140μm or 150μm, etc., which can not only make the screen cover 1 have good impact resistance, but also ensure that the screen cover 1 has high folding performance. When the thickness of the second film layer 14 is less than 25 μm, the thickness of the second film layer 14 is too thin, resulting in the deformation of the buffer layer 11 still being able to be transmitted to the flexible screen 2, making it difficult for the impact resistance of the folding screen module to meet the use requirements; when the thickness of the second film layer 14 is greater than 150 μm, the thickness of the second film layer 14 is too thick. Since the second film layer 14 itself is a high modulus material, it is not convenient to fold, and an excessively thick second film layer 14 will also cause the overall thickness of the folding screen module to increase, thereby affecting the folding performance of the folding screen module.

[0089] Preferably, the thickness of the second film layer 14 is 25μm to 75μm. For example, the thickness of the second film layer 14 can be 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm or 75μm, etc., which can not only make the screen cover 1 have good impact resistance, but also ensure that the screen cover 1 has excellent folding performance.

[0090] Furthermore, the modulus of the second film layer 14 should be no less than 1 GPa to ensure that the second film layer 14 does not produce a large deformation after the screen cover 1 is impacted, thereby preventing the deformation of the buffer layer 11 from being transmitted to the flexible screen 2.

[0091] Furthermore, the material of the second film layer 14 can be transparent polyimide (Colorless polyimide, abbreviated as CPI), polyester (Polyethylene terephthalate, abbreviated as PET), epoxy resin (Epoxy resin, abbreviated as EP) or ultra thin glass (Ultra thin glass, abbreviated as UTG) and the like.

[0092] Furthermore, the second film layer 14 and the first film layer 12 are made of the same material, which simplifies the processing technology of the screen cover 1 and reduces the production cost of the screen cover 1.

[0093] In order to illustrate the impact resistance of the screen cover 1 provided in this embodiment, a comparative experiment is conducted on the impact resistance of the folding screen module with screen cover plates of different structures. The comparative experimental results are shown in Table 3. The specific experimental method is a falling ball impact test (reference Figure 3); The folding screen modules in each group of embodiments have the same parameters except for the structure of the screen cover 1, and the other experimental conditions are also the same. Each experimental group represents a group of sample folding screen modules, and the experimental results are the average values ​​of the experimental results of the sample folding screen modules in the group. Table 3

[0094]

[0095] According to the experimental data in Table 3, it can be seen that the control group 21 uses a PET layer without buffering performance, and the module's anti-falling ball impact height is 2cm; the experimental group 21 uses a TPU layer with a buffering effect, and the module's anti-falling ball impact height is 16cm; the experimental groups 22 and 23 add a high modulus PET (i.e., the second film layer 14) between the TPU (i.e., the buffer layer) and the flexible screen, and the module's anti-falling ball impact heights are 30cm and 26cm, respectively. Therefore, the screen cover 1 provided in the embodiment of the present application can effectively reduce impact stress and reduce the tensile strain of the TFT layer caused by impact stress by setting the buffer layer 11, thereby improving the impact resistance of the folding screen module; the impact resistance of the folding screen module can be further increased by adding the second film layer 14 between the buffer layer 11 and the flexible screen 2.

[0096] Note: A portion of this patent application document contains material which is subject to copyright protection. The copyright owner reserves all rights reserved except for the production of copies of the material in the patent file or patent record in the Patent Office.

Claims

1. A screen laminate structure for covering a flexible screen, characterized in that: The screen laminate structure includes a first film layer, a first glue layer, a buffer layer, a second glue layer, and a second film layer, wherein: a first film layer, located on a side of the buffer layer away from the flexible screen, the modulus of the first film layer being greater than the modulus of the buffer layer, the first film layer being bonded to the buffer layer via the first adhesive layer, the modulus of the first adhesive layer being less than the modulus of the buffer layer, and the modulus of the buffer layer being 10 MPa to 200 MPa; The second film layer is located on a side of the buffer layer close to the flexible screen, the modulus of the second film layer is greater than the modulus of the buffer layer, the second film layer is bonded to the buffer layer through the second adhesive layer, and the modulus of the second adhesive layer is smaller than the modulus of the buffer layer.

2. The screen stacking structure according to claim 1, characterized in that: The buffer layer includes polyurethane material.

3. The screen laminate structure according to claim 1 or 2, characterized in that: The thickness of the buffer layer is greater than or equal to 50 μm.

4. The screen laminate structure according to any one of claims 1 to 3, characterized in that: The modulus of the first adhesive layer is 10Kpa-100Kpa, and the modulus of the second adhesive layer is 10Kpa-100Kpa.

5. The screen laminate structure according to any one of claims 1 to 4, characterized in that: The thickness of the second film layer is 25 μm to 150 μm.

6. The screen laminate structure according to any one of claims 1 to 4, characterized in that: The thickness of the second film layer is 25 μm to 75 μm.

7. The screen laminate structure according to any one of claims 1 to 4, characterized in that: The modulus of the second film layer is not less than 1 GPa.

8. The screen laminate structure according to any one of claims 1 to 4, characterized in that: The material of the second film layer is transparent polyimide, polyester, epoxy resin or ultra-thin glass.

9. The screen laminate structure according to any one of claims 1 to 8, characterized in that: The second film layer and the first film layer are made of the same material.

10. A display module, characterized in that: include: Flexible screen; A screen laminate structure covers the surface of the flexible screen, and the screen laminate structure is the screen laminate structure described in any one of claims 1-9.

11. A display module, characterized in that: include: Flexible screen; The screen laminate structure is located on the surface of the flexible screen, and the screen laminate structure includes a first film layer, a first adhesive layer, a buffer layer, and a third adhesive layer, wherein: A first film layer is located on a side of the buffer layer away from the flexible screen, the modulus of the first film layer is greater than the modulus of the buffer layer, the first film layer and the buffer layer are bonded by a first adhesive layer, the modulus of the first adhesive layer is less than the modulus of the buffer layer, and the modulus of the buffer layer is 10Mpa to 200Mpa; The buffer layer is bonded to the surface of the flexible screen through a third adhesive layer, the thickness of the third adhesive layer is not less than half of the thickness of the buffer layer, and the modulus of the third adhesive layer is less than the modulus of the buffer layer.

12. The display module according to claim 11, characterized in that: The buffer layer includes polyurethane material.

13. The display module according to claim 11 or 12, characterized in that: The modulus of the first adhesive layer is 10Kpa-100Kpa, and the modulus of the second adhesive layer is 10Kpa-100Kpa.

14. The display module according to any one of claims 11 to 13, characterized in that: The thickness of the buffer layer is not greater than 50 μm, and the thickness of the third adhesive layer is 15 μm to 75 μm.

15. The display module according to any one of claims 11 to 13, characterized in that: The thickness of the buffer layer is 50 μm to 100 μm, and the thickness of the third adhesive layer is 25 μm to 100 μm.

16. The display module according to any one of claims 11 to 13, characterized in that: The thickness of the buffer layer is 100 μm to 150 μm, and the thickness of the third adhesive layer is 50 μm to 125 μm.

17. The display module according to any one of claims 11 to 13, characterized in that: The thickness of the buffer layer is 150 μm to 200 μm, and the thickness of the third adhesive layer is 50 μm to 150 μm.

18. The display module according to any one of claims 11 to 13, characterized in that: The thickness of the buffer layer is not less than 200 μm, and the thickness of the third adhesive layer is not less than 75 μm.

19. An electronic device, characterized in that: A display module comprising any one of claims 11-18.

Images