Protective film and electronic device

Abstract

The invention provides a protective film and electronic equipment, the protective film is used for protecting a flexible display screen, the protective film comprises a first protective layer, an anti-impact layer, a second protective layer and an outer bonding layer, the first protective layer, the anti-impact layer and the second protective layer are sequentially stacked, the first protective layer is fixedly connected with the anti-impact layer, and the second protective layer is fixedly connected with the outer bonding layer. And the outer bonding layer is laminated and connected to the surface, back to the first protection layer, of the second protection layer. The first protective layer and the second protective layer are arranged to be matched with the anti-impact layer in a sandwich mode, so that the problem of adhesive residue of the anti-impact layer and the problem that the stripping force is reduced due to the fact that silicon of the anti-impact layer migrates and permeates into the bonding layer can be avoided. The protective film further comprises a buffer layer which is laminated on the second outer surface of the second protective layer, so that the impact resistance of the protective film is further improved.

Description

Protective films and electronic devices

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on March 22, 2023, with application number 202320648193.6, and priority to the Chinese patent application with the invention name “Protective Film and Electronic Device”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The utility model relates to the technical field of electronic equipment, in particular to a protective film and electronic equipment. Background Art

[0003] With the advancement of technology, some mobile phones and tablets on the market now feature foldable screens. These devices offer a large flexible display when unfolded, and their overall size is reduced when folded, allowing for both portability and a larger flexible display. While the display is in use, it is often covered with a protective film to protect it from bumps and scratches during use and transportation. Foldable flexible displays, in particular, require sufficient impact and compression resistance while also meeting foldability requirements. However, existing screen protectors are either too thick or lack sufficient protection, compromising their performance.

[0004] Utility Model Content

[0005] The utility model provides a protective film and an electronic device, so as to solve the technical problems in the prior art that the protective film has a large thickness or a weak protective capability.

[0006] A protective film for a flexible display screen, comprising a first protective layer, an impact-resistant layer, a second protective layer and an external adhesive layer. The first protective layer, the impact-resistant layer and the second protective layer are stacked in sequence, the first protective layer is fixedly connected to the impact-resistant layer, and the external adhesive layer is stacked and connected to the surface of the second protective layer facing away from the first protective layer.

[0007] The base layer of the protective film in this embodiment is divided into a first protective layer and a second protective layer, and the impact-resistant layer is clamped between the first protective layer and the second protective layer. The thickness of the protective film is not increased, the impact resistance is increased (high strain rate scenario), and the anti-extrusion ability (low strain rate scenario) is also increased, thereby improving the relevant performance of the protective film.

[0008] In one embodiment, the first protective layer includes a first outer surface and a first inner surface arranged opposite to the first outer surface; the second protective layer includes a second outer surface and a second inner surface arranged opposite to the second outer surface, and the two opposite surfaces of the impact-resistant layer are respectively connected and fixed to the first inner surface and the second inner surface.

[0009] In one embodiment, the protective film further includes an adhesive layer, which is stacked between the impact-resistant layer and the second protective layer, and the adhesive layer bonds the surface of the impact-resistant base layer toward the second protective layer surface and the surface of the second protective layer toward the first protective layer.

[0010] In one embodiment, the protective film further includes a buffer layer. The second protective layer includes a second outer surface and a second inner surface opposite the second outer surface. The adhesive layer is bonded to the second inner surface. The buffer layer is laminated on the second outer surface and fixedly connected to the second protective layer via a transparent adhesive layer. The adhesive layer is laminated and connected to the surface of the buffer layer opposite the second protective layer. The provision of the buffer layer further enhances the impact resistance of the protective film.

[0011] In one embodiment, the thickness of the first protective layer is 50 um, and the thickness of the second protective layer is 12 um.

[0012] In one embodiment, the material of the first protective layer can be one or a combination of two of PI (Polyimide), PET (Polyethylene terephthalate), UTG (Ultra Thin Glass), PEEK (polyetheretherketone), PEN (polyethylene naphthalate) and TPU (Thermoplastic polyurethane).

[0013] In one embodiment, the hardness of the first protective layer and the second protective layer is greater than the hardness of the impact-resistant layer, ensuring that the protective film has sufficient strength.

[0014] In one embodiment, the thickness of the first protective layer is greater than the thickness of the second protective layer.

[0015] The present application provides a flexible display screen comprising a display surface and a protective film, the protective film being laminated on and covering the display surface, and the adhesive layer being bonded and fixed to the display surface. The first and second protective layers provide overall rigidity to the protective film, reducing overall deformation and enhancing screen protection. For high strain rate scenarios, the first protective layer, the impact-resistant layer, and the second protective layer form a hard-soft-hard laminated combination, while the impact-resistant material layer utilizes its energy-absorbing properties to reduce the transmission of impact stress to the screen.

[0016] The present application provides an electronic device, which includes the protective film and a flexible display screen. The flexible display screen includes a display surface. The protective film is stacked on and covers the display surface. The adhesive layer is bonded and fixed to the display surface.

[0017] In summary, the present application can avoid the problem of residual glue in the impact-resistant layer and the problem of reduced peeling force caused by the migration and penetration of silicon in the impact-resistant layer into the adhesive layer by arranging the first protective layer and the second protective layer to form a sandwich with the impact-resistant layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be described below.

[0019] FIG1 is a schematic structural diagram of an electronic device provided by the present application;

[0020] FIG2 is a schematic cross-sectional view of a first embodiment of a protective film of the present application;

[0021] FIG3 is an exploded schematic diagram of the protective film shown in FIG2 ;

[0022] FIG4 is a cross-sectional schematic diagram of a second embodiment of a protective film provided by the present application;

[0023] FIG5 is a schematic cross-sectional view of a third embodiment of the protective film provided in the present application. DETAILED DESCRIPTION

[0024] The embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0025] Please refer to Figure 1, which is a schematic diagram of the structure of an electronic device 1000 provided in this application. This utility model provides an electronic device 1000. Specifically, electronic device 1000 includes, but is not limited to, electronic products such as a foldable mobile phone, a tablet computer, and a laptop computer. In the embodiments of this utility model, the electronic device 1000 is described as a foldable mobile phone.

[0026] Electronic device 1000 includes a flexible display 100 and a main body 200. Flexible display 100 is attached to one side of main body 200 along the thickness of the electronic device. The electronic device in this embodiment is a foldable mobile phone. Main body 200 is equipped with a hinge mechanism that enables rotation of main body 200, driving flexible display 100 to fold, thereby achieving the foldability of the electronic device. Main body 200 includes a housing and other electronic device components, such as a circuit board, battery, and functional components. These functional components may include sockets, speakers, sensors, and the like.

[0027] Please refer to Figures 2 and 3. Figure 2 is a schematic diagram of the cross-sectional structure of the first embodiment of the protective film of the present application, and Figure 3 is a schematic diagram of the decomposition of the protective film shown in Figure 2, which is applied to the electronic device 1000 shown, specifically attached to and covering the surface of the flexible display screen 100, for protecting the flexible display screen 100.

[0028] The protective film 10 of this embodiment includes a first protective layer 11, an impact-resistant layer 12, a second protective layer 13 and an outer bonding layer 14. Along the thickness direction of the protective film 10, the first protective layer 11, the impact-resistant layer 12, the second protective layer 13 and the outer bonding layer 14 are stacked and connected in sequence. The first protective layer 11 includes a first outer surface 111 and a first inner surface 112, and the first outer surface 111 and the first inner surface 112 are arranged opposite to each other. The impact-resistant layer 12 includes a first surface 121 and a second surface 122, and the first surface 121 and the second surface 122 are arranged opposite to each other. The second protective layer 13 includes a second outer surface 131 and a second inner surface 132, and the second outer surface 131 and the second inner surface 132 are arranged opposite to each other. The first inner surface 112 of the first protective layer 11 is stacked and connected to the first surface 121 of the impact-resistant layer 12, and the second surface 122 of the impact-resistant layer 12 is stacked and connected to the second inner surface 132 of the second protective layer 13. The outer adhesive layer 14 is laminated on the second outer surface 131 of the second protective layer 13 .

[0029] In this embodiment, the outer adhesive layer 14 is an optically clear adhesive (OCA). The materials of OCA can include, but are not limited to, silicone, acrylic resin, unsaturated polyester, polyurethane, epoxy resin, etc. Since the transmittance of OCA is generally above 95%, using OCA for the outer adhesive layer 14 can ensure a higher transmittance for the protective film 10. In other embodiments, the outer adhesive layer 14 can also be made of other double-sided adhesives.

[0030] It should be noted that when the protective film 10 is attached to the flexible display screen 100, the external adhesive layer 14 contacts the display surface of the flexible display screen 100; when the protective film 10 is not in use, the surface of the external adhesive layer 14 can also be covered with a retaining film to maintain the stickiness of the external adhesive layer 14.

[0031] The impact-resistant layer 12 is used to improve the impact and extrusion resistance of the protective film 10. Specifically, the impact-resistant layer 12 is made of a silicone material that is resistant to compression deformation. Silicone has good elasticity and excellent shockproof properties, which can effectively improve the impact and extrusion resistance of the protective film 10.

[0032] The first protective layer 11 is the supporting body of the protective film 10. In order to ensure that the protective film 10 does not affect the user's visual experience and has a certain rigidity, the first protective layer 11 uses a rigid film material with a higher modulus. The material type can be PI (Polyimide), PET (Polyethylene terephthalate), UTG (Ultra Thin Glass), PEEK (polyetheretherketone), PEN (polyethylene naphthalate) and TPU (Thermoplastic polyurethane), etc., which can be one or a combination of two. Specifically, the material of the first protective layer 11 can be PET, PI (Polyimide). The first protective layer 11 needs to have a transmittance of 80%, or a transmittance of more than 80%. At the same time, the selection of the above materials for the first protective layer 11 can make the protective film 10 have better supporting strength and flexibility. In other embodiments, the transmittance of the first protective layer 11 can also be at least 70%.

[0033] The second protective layer 13 is the supporting body of the protective film 10. In order to ensure that the protective film 10 does not affect the user's visual experience and has a certain rigidity, the second protective layer 13 uses a rigid film material with a higher modulus. The material type can be PI (Polyimide), PET (Polyethylene terephthalate), UTG (Ultra Thin Glass), PEEK (polyetheretherketone), PEN (polyethylene naphthalate) and TPU (Thermoplastic polyurethane), etc., which can be one or a combination of two. Specifically, the material of the second protective layer 13 can be PET, PI (Polyimide). The first protective layer 11 needs to have a transmittance of 80%, or a transmittance of more than 80%. At the same time, the selection of the above materials for the second protective layer 13 can give the protective film 10 better supporting strength and flexibility. The materials of the second protective layer 13 and the first protective layer 11 can be the same or different. In this embodiment, the second protective layer 13 is made of the same material as the first protective layer 11. In other embodiments, the transmittance of the second protective layer 13 may also be at least 70%.

[0034] The thickness of the first protective layer 11 can be 5 μm to 200 μm. In this embodiment, the thickness of the first protective layer 11 is 50 μm. The thickness of the second protective layer 13 can be 5 μm to 200 μm. In this embodiment, the thickness of the second protective layer 13 is 12 μm. It is understood that the thickness of the second protective layer 13 and the first protective layer 11 can be the same or different. The thickness of the second protective layer 13 is less than or equal to the thickness of the first protective layer 11. Of course, the thickness of the second protective layer 13 can also be greater than the thickness of the first protective layer 11.

[0035] The protective film 10 provided in the first embodiment of the present invention was subjected to pointed impact and pointed extrusion tests. Specifically, the test results are shown in Table 1. A comparative protective film is provided. Compared with the protective film 10 of the first embodiment, the comparative protective film is different in that the comparative protective film includes a protective layer and an adhesive layer. It should be noted that the pointed impact test is to attach the protective film 10 to the flexible display screen 100, and use a stainless steel pointed tip to squeeze the surface of the protective film 10 away from the flexible display screen 100 to test the strain of the flexible display screen 100. Specifically, the pointed impact test is to attach the protective film 10 to the flexible display screen 100, and let the stainless steel pointed tip fall freely from a certain height onto the surface of the protective film 10 away from the flexible display screen 100 to test the strain of the flexible display screen 100.

[0036] The test height starts at 1 cm and is increased in increments of 0.5 cm until the display screen is damaged (such as the appearance of broken bright spots, black spots, bright lines, flowery screen, and other functional malfunctions), and the failure height of the flexible display screen 100 is recorded when it is damaged. The conditions for the pointed extrusion test are similar. Unlike the pointed impact test, the test is to squeeze the protective film and the flexible display screen 100 with a certain pressure. The squeezing force starts at 0.5 kg and increases in increments of 0.5 kg until the display screen fails. In the present utility model, the test conditions for the protective film of the first embodiment and the comparative example are the same, including the diameter of the pointed tip, the squeezing force, and the height of the free fall.

[0037] Table 1: Mechanical properties of the protective films of the first embodiment and the comparative example

[0038] Comparing the mechanical indicators of the protective films of the first embodiment and the comparative example, it can be found that: after the second protective layer 13 and the first protective layer 11 are used in this embodiment, and the impact resistance layer 12 is provided, the impact resistance of the protective film of the present technical solution is improved by 36% compared with the existing solution 1 and 13% compared with the existing solution 2, while the thickness of the protective film of the previous solution is the same as that of the previous solution. The anti-extrusion ability is comparable to that of the existing solution 1 and is improved by 15% compared with the existing solution 2. The rebound force is reduced by 5% compared with the existing solution 1. In other words, without increasing the thickness of the protective film, the impact resistance (high strain rate scenario) can also be improved to meet the anti-extrusion ability (low strain rate scenario), thereby improving the relevant performance of the protective film.

[0039] Furthermore, the first protective layer 11 and the second protective layer 13 in this embodiment serve as the base layer of the protective film, providing primary protection. The stacking of the first and second protective layers 11, 13 enhances the flexibility of adjusting the protective layers. The thicknesses of the first and second protective layers 11, 13 can be flexibly adjusted based on design requirements, offering greater adjustability than the single-base film solution of existing technologies.

[0040] The manufacturing method of the protective film 10 provided in the first embodiment of the present application is as follows:

[0041] Step 1: Coating the impact-resistant layer 12 on the first inner surface 112 of the first protective layer 11;

[0042] Step 2: Laminating the second protective layer 13 and the impact-resistant layer 12 so that the second surface 122 of the impact-resistant layer 12 contacts the second inner surface 132 of the second protective layer 13. Specifically, the impact-resistant layer 12 and the second protective layer 13 are directly connected by plasma treatment on the surface of the second protective layer 13, thereby rolling the two together.

[0043] Step 3: forming an outer adhesive layer 14 on the second outer surface 131 of the second protective layer 13 to obtain the protective film 10 provided in the first embodiment.

[0044] Compared with the protective film of the existing solution, the protective film of this embodiment does not need to increase the total thickness of the first protective layer 11 and the second protective layer 13 as the base layer, and can also achieve the protective strength of the protective film, avoiding increasing the base layer thickness and significantly increasing the laminated rebound force as in the existing technology, thereby reducing the cost of the protective layer film.

[0045] Please refer to FIG. 4 , which is a cross-sectional schematic diagram of a second embodiment of the protective film 20 provided in this application.

[0046] The protective film 20 of this embodiment includes a first protective layer 21, an impact-resistant layer 22, a second protective layer 23, an adhesive layer 24 and an outer adhesive layer 25. Along the thickness direction of the protective film 20, the first protective layer 21, the impact-resistant layer 22, the adhesive layer 24, the second protective layer 23 and the outer adhesive layer 25 are stacked and connected in sequence. The first protective layer 21 includes a first outer surface 211 and a first inner surface 212, and the first outer surface 211 and the first inner surface 212 are arranged relative to each other. The impact-resistant layer 22 includes a first surface (not marked in the figure) and a second surface (not marked in the figure), and the first surface and the second surface are arranged relative to each other. The second protective layer 23 includes a second outer surface 232 and a second inner surface 231, and the second outer surface 232 and the second inner surface 231 are arranged relative to each other.

[0047] The first inner surface 212 of the first protective layer 21 is laminated and connected to the first surface of the impact-resistant layer 22. The adhesive layer 24 is laminated between the second surface of the impact-resistant layer 22 and the second inner surface 231 of the second protective layer 23. The adhesive layer 24 bonds the impact-resistant layer 22 and the second protective layer 23. In other words, the first protective layer 21 and the second protective layer 23 are fixedly connected by the adhesive layer 24.

[0048] The outer adhesive layer 25 is laminated on the second outer surface 232 of the second protective layer 23 and is used to bond the protective film 20 to the flexible display screen of the electronic device.

[0049] In this embodiment, the adhesive layer 24 and the outer adhesive layer 25 are made of optically clear adhesive (OCA). The material of OCA can be, but is not limited to, silicone, acrylic resin, unsaturated polyester, polyurethane, epoxy resin, etc. Since the transmittance of OCA is generally above 95%, using OCA for the adhesive layer 24 and the outer adhesive layer 25 can ensure a higher transmittance of the protective film 20.

[0050] It should be noted that when the protective film 20 is attached to the flexible display screen 100, the external adhesive layer 25 contacts the display surface of the flexible display screen 100; when the protective film 20 is not in use, the surface of the external adhesive layer 25 can also be covered with a retaining film to maintain the stickiness of the external adhesive layer 25.

[0051] The material of the impact-resistant layer 22 may be the same as that of the first embodiment. The material of the first protective layer 21 and the second protective layer 23 may be the same as that of the first protective layer 11 and the second protective layer 13 of the first embodiment. The first protective layer 21 and the second protective layer 23 use a rigid film material with a higher modulus. The material type may be PI (Polyimide), PET (Polyethylene terephthalate), UTG (Ultra Thin Glass), PEEK (polyetheretherketone), PEN (polyethylene naphthalate) and TPU (Thermoplastic polyurethane), etc., and may be one or a combination of two thereof. The material of the second protective layer 23 and the first protective layer 21 may be the same or different. In this embodiment, the material of the second protective layer 23 and the first protective layer 21 is the same.

[0052] The thickness of the first protective layer 21 can be 5 μm-200 μm, and in this embodiment, the thickness of the first protective layer 21 is 50 μm. The thickness of the second protective layer 23 can be 5 μm-200 μm, and in this embodiment, the thickness of the second protective layer 23 is 12 μm.

[0053] In addition, for a comparison of the silicon migration phenomenon of the protective films of the second embodiment and the comparative example, please refer to the table below.

[0054] Table 2: Comparison of silicon migration phenomenon of the protective film of the second embodiment and the comparative example

[0055] It is clear that the design of the stacking scheme of the first protective layer 21 and the second protective layer 23 is adopted, and the impact-resistant layer 22 is set between the first protective layer 21 and the second protective layer 23, which can avoid the problem of residual glue in the impact-resistant material layer of the impact-resistant layer 22 (because the internal strength of the silicone system material of the impact-resistant layer 22 is relatively poor, it will be delaminated from the impact-resistant material layer when the film is torn off and reworked, resulting in residual glue). In addition, because the material of the silicone system has the phenomenon of small molecule silicon migration, under long-term storage conditions, the small molecule silicon of the silicone impact-resistant layer will migrate to the use bonding surface of the outer bonding layer 25, resulting in reduced viscosity of the outer bonding layer 25 and it will fall off from the display screen; in this embodiment, a second protective layer 23 is placed between the outer bonding layer 25 and the silicone impact-resistant layer 22. Since the material of the second protective layer 23 is not silicone, it can prevent the diffusion of small silicone molecules to the outer bonding layer 25, and can ensure a relatively stable bonding force of the outer bonding layer.

[0056] Please refer to Figure 5, which is a cross-sectional schematic diagram of a third embodiment of the protective film provided by this application. Unlike the second embodiment described above, this embodiment further comprises at least one buffer layer 26, which is secured to the second protective layer 23 via an adhesive layer 27 (transparent adhesive layer). An external adhesive layer 25 is provided on the outer surface of the buffer layer 26. The buffer layer 26 is formed from an elastomeric film such as TPU, providing the protective film 20 with enhanced impact resistance.

[0057] In the protective film described in the above embodiments of the present application, the first protective layer and the second protective layer provide overall rigidity of the protective film, reduce overall deformation of the protective film, and enhance the protection capability of the flexible display screen 100; for high strain rate scenarios, the first protective layer, the impact-resistant layer, and the second protective layer form a hard-soft-hard laminated combination, while the impact-resistant material layer exerts its energy-absorbing properties to reduce the impact stress transferred to the flexible display screen 100.

[0058] The above are only some of the embodiments and implementations of the present invention. The scope of protection of the present invention is not limited to these. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this utility model should be included in the scope of protection of the present utility model. Therefore, the scope of protection of the present utility model should be based on the scope of protection of the claims.

Claims

1. A protective film for a flexible display screen, characterized in that: The protective film includes a first protective layer, an impact-resistant layer, a second protective layer and an external bonding layer. The first protective layer, the impact-resistant layer and the second protective layer are stacked in sequence. The first protective layer is fixedly connected to the impact-resistant layer. The external bonding layer is stacked and connected to the surface of the second protective layer facing away from the first protective layer.

2. The protective film according to claim 1, characterized in that: The first protective layer includes a first outer surface and a first inner surface arranged opposite to the first outer surface; the second protective layer includes a second outer surface and a second inner surface arranged opposite to the second outer surface, and the two opposite surfaces of the impact-resistant layer are respectively connected and fixed to the first inner surface and the second inner surface.

3. The protective film according to claim 1, characterized in that: The protective film further includes a bonding layer, which is stacked between the impact-resistant layer and the second protective layer, and bonds a surface of the impact-resistant base layer facing the second protective layer and a surface of the second protective layer facing the first protective layer.

4. The protective film according to claim 3, characterized in that: The protective film also includes a buffer layer, the second protective layer includes a second outer surface and a second inner surface arranged opposite to the second outer surface, the adhesive layer is bonded to the second inner surface, the buffer layer is stacked on the second outer surface and fixedly connected to the second protective layer through a transparent adhesive layer, and the adhesive layer is stacked and connected to the surface of the buffer layer opposite to the second protective layer.

5. The protective film according to any one of claims 1 to 4, characterized in that: The thickness of the first protective layer is 50 um, and the thickness of the second protective layer is 12 um.

6. The protective film according to any one of claims 1 to 4, characterized in that: The material of the first protective layer can be one or a combination of two of PI (Polyimide), PET (Polyethylene terephthalate), UTG (Ultra Thin Glass), PEEK (polyetheretherketone), PEN (polyethylene naphthalate) and TPU (Thermoplastic polyurethane).

7. The protective film according to any one of claims 1 to 4, characterized in that: The hardness of the first protective layer and the second protective layer is greater than the hardness of the impact-resistant layer.

8. The protective film according to any one of claims 1 to 4, characterized in that: The thickness of the first protective layer is greater than the thickness of the second protective layer.

9. A flexible display screen, characterized in that: The flexible display screen comprises a display surface and the protective film according to any one of claims 1 to 8, wherein the protective film is stacked on and covers the display surface, and the adhesive layer is bonded and fixed to the display surface.

10. An electronic device, characterized in that: It comprises a protective film and a flexible display screen as claimed in any one of claims 1 to 8, wherein the flexible display screen comprises a display surface, the protective film is stacked on and covers the display surface, and the adhesive layer is bonded and fixed to the display surface.

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