A protective film and its application method

Abstract

This invention discloses a protective film and a method for applying the protective film. The protective film includes a first release film, a UV film, and a second release film. The UV film is disposed on the first release film, and the second release film is disposed on the UV film. The second release film has a light-transmitting area and a light-shielding area. In the process of applying the protective film to the display screen according to this embodiment of the invention, during the curing of the UV film under the light-transmitting area of ​​the second release film in a vacuum environment, the deformed optical adhesive layer corresponding to the light-shielding area will not cure due to the obstruction of the light-shielding area. This allows the deformed optical adhesive layer to recover, thereby effectively avoiding top-printing problems and improving product shipment quality and user experience.

Description

Technical Field

[0001] This invention relates to the field of protective film bonding technology, and more specifically to a protective film and its bonding method. Background Technology

[0002] With the widespread adoption of flexible AMOLED screen smartphones, the thinner, lighter, and more energy-efficient form factor has led to the increasingly widespread use of displays. However, this application presents challenges for hot-bending films, as issues such as lifting and air bubbles can occur when bonding the film to the curved areas on the left and right sides of the display. To address this, UV-cured films have replaced hot-bending films as the shipping film for curved smartphones. UV films offer advantages such as resistance to lifting, air bubbles, and bacterial residue, and both UV films and their application methods are widely used. However, the UV film application process in these technologies is prone to poor top-printing, affecting product quality and user experience. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the above-mentioned technical problems.

[0004] Therefore, embodiments of the present invention propose a protective film to solve the technical problem of poor top printing during the UV film application process.

[0005] Embodiments of the present invention also propose a protective film application method to solve the technical problem of poor top printing during the UV film application process.

[0006] The protective film of the present invention includes:

[0007] First release film,

[0008] UV film; the UV film is disposed on the first release film; and

[0009] A second release film is disposed on the UV film, and the second release film includes a light-transmitting area and a light-blocking area.

[0010] In some embodiments, the light-shielding area corresponds to a non-flat area under the display screen in the thickness direction of the display screen.

[0011] In some embodiments, the protective film includes a planar region and a curved region, and the light-shielding area is disposed on the planar region of the second release film so as to completely block the planar region of the second release film; wherein, the planar region corresponds to the planar display area on the display screen, and the curved region corresponds to the curved display area on the display screen.

[0012] In some embodiments, the light-shielding area is formed by blackening the second release film; and / or, the second release film is formed by splicing a light-shielding release film and a light-transmitting release film, wherein the position of the light-shielding release film corresponds to the position of the light-shielding area.

[0013] In some embodiments, the blackening process includes at least one of lamination, printing, and spraying methods on the second release film.

[0014] In some embodiments, the non-flat area includes the mid-frame junction step and / or the device avoidance step.

[0015] In some embodiments, the non-flat area includes the gold-plated foam auxiliary material area under the display screen.

[0016] The protective film application method of this invention uses the protective film described in any of the above embodiments of this invention, and the protective film application method includes the following steps:

[0017] Remove the first release film and attach the UV film to the display screen;

[0018] The UV film under the light-transmitting area on the second release film is cured in a vacuum environment;

[0019] Remove the vacuum environment and remove the second release film.

[0020] In some embodiments, after removing the second release film, the UV film under the light-shielding area on the second release film is cured.

[0021] In some embodiments, before curing the UV film under the light-shielding area on the second release film, the display screen is left to stand for a preset time. If the optical adhesive layer in the display screen does not deform, the vacuum environment is then removed and the second release film is taken off.

[0022] According to the protective film of the present invention, by setting a light-shielding area that is not transparent to UV light on the second release film, the structure of the protective film is optimized. During the application of the protective film, a protective film application method that selectively cures part of the UV film or applies segmented coating to all of the UV film can be used. Both methods can eliminate top printing on the front of the 3D display screen during the film application process. Without increasing production costs, the occurrence of top printing defects in mobile terminals is reduced, and product quality and user satisfaction are improved. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a UV film in related technologies;

[0024] Figure 2 This is a structural diagram of the display screen in related technologies;

[0025] Figure 3 This is a schematic diagram of the structure of the protective film according to an embodiment of the present invention.

[0026] Figure label:

[0027] Second release film 1; UV film 2; First release film 3;

[0028] 5. Cover plate; 6. Optical adhesive layer; 7. Screen body; 8. Non-flat area;

[0029] Protective film 100;

[0030] Second release film 10; light-transmitting area 101; light-shielding area 102; UV film 20; first release film 30. Detailed Implementation

[0031] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0032] The following is for reference. Figure 1 The structure of the pre-application UV film (protective film) in related technologies is described. The protective film includes a second release film 1, a UV film 2, and a first release film 3. For example... Figure 2 As shown, the display screen to which the protective film is to be attached is a flexible curved screen including a flat display area and a curved display area. The display screen includes a screen body 7, an optical adhesive layer 6, and a cover plate 5. The cover plate 5 is attached to the screen body 7 by the optical adhesive layer. There is a non-flat area 8 under the display screen. The non-flat area 8 includes the middle frame step difference, the component step difference, and the auxiliary materials such as gold-plated foam.

[0033] The method for attaching the protective film to the display screen is as follows: First, remove the first release film 3 and attach the UV film 2 to the cover plate 5 of the display screen; in a vacuum environment, attach the UV film 2 completely to the curved display area of ​​the display screen, and then cure the UV film 2 by UV light irradiation to ensure that the UV film 2 fully adheres to the curved display area of ​​the 3D display screen; finally, remove the second release film 1.

[0034] During the UV film 2 lamination process, the front of the cover plate 5 is subjected to a pressure of 70-100 kPa. Due to the characteristics of the flexible curved screen, visible top marks will be generated in the non-flat area 8 and in the areas of auxiliary materials such as gold-plated foam. When the UV film 2 is cured by UV light, the optical adhesive layer 6 under the cover plate 5 is cured in a deformed state (e.g., Figure 2 As shown in the image, the visible top print on the front of the display screen will remain, posing a significant risk to the aftermarket.

[0035] Conventional optimization methods involve rounding the corners in uneven areas and using mildly elastic auxiliary materials, but the improvement achieved by this approach is limited. Therefore, how to effectively improve the obvious top-printing defects on the front of curved displays in existing technologies is a technical problem that urgently needs to be solved by those skilled in the art.

[0036] Examples of the invention are described in detail below, illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The examples described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0037] like Figure 3 As shown, an embodiment of the present invention proposes a protective film 100 including a first release film 30, a UV film 20, and a second release film 10. The UV film 20 is disposed on the first release film 30, and the second release film 10 is disposed on the UV film 20. The second release film 10 has a light-transmitting area 101 and a light-blocking area 102.

[0038] To make the technical solution of this application easier to understand, the following description uses the example of the protective film having the thickness direction aligned with the top and bottom directions, where the top and bottom directions are as follows: Figure 3 As shown.

[0039] UV film 20 is disposed above first release film 30, and second release film 10 is disposed above UV film 20. In other words, UV film 20 has an upper surface and a lower surface opposite to each other in the vertical direction, first release film 30 is disposed below the lower surface of UV film 20, and second release film 10 is disposed above the upper surface of UV film 20.

[0040] Those skilled in the art will understand that the light-transmitting area 101 allows UV light to pass through, while the light-shielding area 102 prevents UV light from passing through. Therefore, during the process of attaching the UV film 20 to the display screen, when the second release film 10 is irradiated with UV light to cure the UV film 20, the UV light can only pass through the second release film 10 from the light-transmitting area 101 to cure the area of ​​the UV film 20 corresponding to the light-transmitting area 101. Figure 2 As shown, the optical adhesive layer 6 deformed under the cover plate 5 corresponding to the light-shielding area 102 (e.g.) Figure 2 As shown, the light-blocking area 102 will not cure the light.

[0041] In this embodiment, the display screen can be understood as a display screen of a mobile terminal such as a mobile phone display screen or a computer display screen, specifically a flexible curved screen. The protective film in this embodiment is the shipping UV film 20 for the flexible curved display screen, wherein the first release film 30 can be a light release film, and the second release film 10 can be a heavy release film.

[0042] In some embodiments, the light-shielding area 102 corresponds to the non-flat area 8 under the display screen in the thickness direction of the display screen.

[0043] The thickness direction of the display screen is consistent with the thickness direction of the protective film 100, that is, the thickness direction of the display screen is consistent with... Figure 3 The vertical direction is consistent. Among them, the light-shielding area 102 corresponds to the uneven area 8 under the display screen in the vertical direction so that the uneven area 8 can be blocked by the light-shielding area 101.

[0044] The protective film application method of this embodiment of the invention includes the following steps: First, remove the first release film 30 and apply the UV film 20 to the display screen; then, in a vacuum environment, cure the UV film 20 under the light-transmitting area 101 of the second release film 10; after that, remove the vacuum environment and remove the second release film 10.

[0045] Therefore, during the process of attaching the protective film 100 of this embodiment of the invention to the display screen, when the UV film 20 under the light-transmitting area 101 of the second release film 10 is cured in a vacuum environment, the deformed optical adhesive layer 6 (such as...) corresponding to the light-shielding area 102... Figure 2 As shown, because the light-shielding area 102 does not cure, the deformed optical adhesive layer 6 can be restored, thereby effectively avoiding the occurrence of top printing problems and improving the product's shipping quality and user experience.

[0046] In some embodiments, the non-flat area 8 includes the mid-frame junction step and / or the device avoidance step.

[0047] The non-flat area 8, including the mid-frame junction and / or the component avoidance junction, can be understood as: the non-flat area 8 only includes the mid-frame junction; or, the non-flat area 8 only includes the component avoidance junction; or, the non-flat area 8 includes both the mid-frame junction and the component avoidance junction.

[0048] Among them, the mid-frame junction is the junction between the VC tube and the mid-frame under the display screen 7. The device avoidance junction can be understood as the mid-frame under the display screen being treated with a reduction in surface area to avoid devices (e.g., the display screen's FPC). The device avoidance junction is formed between the area on the mid-frame with the reduction in surface area and the area without the reduction in surface area.

[0049] When the UV film 20 under the light-transmitting area 101 on the second release film 10 is cured, the optical adhesive layer 6 corresponding to the junction of the middle frame and the component avoidance section is prone to deformation. Therefore, by using the light-shielding area 102 to block the optical adhesive layer 6 corresponding to the junction of the middle frame and the component avoidance section, the top printing problem can be effectively avoided, and the product shipment quality and user experience can be improved.

[0050] Optionally, the optical adhesive layer 6 is an OCA adhesive layer (e.g., Momentive TUV-C). The UV film 20 can be cured and bonded to the display screen by UV light irradiation.

[0051] In some embodiments, the non-flat area 8 includes a gold-plated foam auxiliary material area under the display screen.

[0052] The gold-plated foam auxiliary material area is located at the edge of the display screen. Specifically, gold-plated foam is distributed along the edge of the display screen to prevent static electricity. This gold-plated foam auxiliary material area includes at least the gold-plated foam area corresponding to the position of the front-facing camera.

[0053] When the UV film 20 under the light-transmitting area 101 on the second release film 10 is cured, the optical adhesive layer 6 corresponding to the gold-plated foam auxiliary material area is prone to deformation. Therefore, by using the light-shielding area 102 to block the optical adhesive layer 6 corresponding to the gold-plated foam auxiliary material area, the top printing problem can be effectively avoided, and the product shipment quality and user experience can be improved.

[0054] Of course, in other embodiments, the uneven area 8 also includes other areas that may cause top imprint problems on the front of the display screen, which will not be listed here. However, in order to eliminate top imprint defects in the process of applying the screen film, the light-shielding area 102 in this embodiment can be provided on the second release film 10.

[0055] In some embodiments, the protective film 100 includes a planar region and a curved region, and the light-shielding region 102 is disposed on the planar region of the second release film 10 so as to completely block the planar region of the second release film 10; wherein, the planar region corresponds to the planar display area on the display screen, and the curved region corresponds to the curved display area on the display screen.

[0056] In actual application, it was found that the flat display area of ​​the screen is most prone to top-printing problems. The flat area of ​​the protective film 100 corresponds to the flat display area of ​​the screen in the vertical direction, and the curved area of ​​the protective film 100 corresponds to the curved display area of ​​the screen in the vertical direction. Therefore, the light-blocking area 102 is set on the flat area of ​​the second release film 10 and completely blocks the flat area of ​​the second release film 10, which can more effectively avoid the occurrence of top-printing problems and improve the product's shipping quality and user experience.

[0057] In some embodiments, the light-shielding area 102 is formed by blackening the second release film 10; and / or the second release film 10 is formed by splicing a light-shielding release film and a light-transmitting release film, wherein the position of the light-shielding release film corresponds to the position of the light-shielding area 102.

[0058] For example, a light-shielding area can be formed on the second release film 10 simply by blackening it; or the second release film 10 can be formed by splicing a light-shielding release film and a light-transmitting release film together, and the light-shielding release film can be used to form a light-shielding area on the second release film 10; or a portion of the light-shielding area can be formed on the second release film 10 by blackening it, and another portion of the light-shielding area can be formed on the second release film 10 by splicing a light-shielding release film and a light-transmitting release film together.

[0059] The second release film 10 is formed by splicing a light-shielding release film and a light-transmitting release film. This can be understood as the second release film 10 consisting of a first part and a second part. The first part is a light-shielding release film, and the second part is a light-transmitting release film. The first part and the second part are spliced ​​together to form the second release film 10. The light-shielding release film is made of a material that prevents UV light from passing through, while the light-transmitting release film is made of a material that allows UV light to pass through.

[0060] In some embodiments, the blackening process includes at least one of the following methods: coating, printing, or spraying on the second release film 10.

[0061] The blackening treatment includes at least one of the following methods: lamination, printing, or spraying on the second release film 10. This can be understood as: the blackening treatment includes only one of the following methods: lamination, printing, and spraying on the second release film 10; or, the blackening treatment includes two of the following methods: lamination, printing, and spraying on the second release film 10; or, the blackening treatment includes all of the following methods: lamination, printing, and spraying on the second release film 10.

[0062] For example, the second release film 10 is coated with a film corresponding to the uneven area 8 under the display screen so as to form a light-shielding area 102 on the second release film 10.

[0063] Of course, in other embodiments, based on the second release film 10 being formed by splicing a light-shielding release film and a light-transmitting release film, at least one of the following methods—coating, printing, and spraying—can be used on the light-shielding release film to further optimize the light-shielding effect of the light-shielding area. It is understood that other methods of setting up the second release film 10 to block UV light are all within the protection scope of this invention.

[0064] The protective film application method in this embodiment includes the following steps:

[0065] Remove the first release film 30 and attach the UV film 20 to the display screen;

[0066] In a vacuum environment, the UV film 20 under the light-transmitting area 101 on the second release film 10 is cured;

[0067] Remove the vacuum environment and remove the second release film 10.

[0068] The protective film application method proposed in this embodiment of the invention can selectively cure a portion of the UV film 20, that is, only the UV film 20 under the light-transmitting area 101 on the second release film 10 is cured before the second release film 10 is removed. For example, for Figure 2 At least one of the following locations in the uneven area 8 shown is blocked: the mid-frame junction, the component avoidance section, or the gold-plated foam auxiliary material area. Only the UV film 20 under the light-transmitting area 101 on the second release film 10 is cured. After the UV film 20 under the light-transmitting area 101 is cured, the vacuum environment is removed to remove the second release film 10, thereby achieving the purpose of eliminating the front top imprint during the screen film application process.

[0069] Optionally, the UV film 20 adopts a segmented coating protective film application method, that is, the UV film 20 under the light-transmitting area 101 and the UV film 20 under the light-shielding area on the second release film 10 are cured separately in different areas and at different times.

[0070] Optionally, after removing the second release film 10, the UV film 20 under the light-shielding area 102 on the second release film 10 is cured.

[0071] The UV film 20 under the light-shielding area 102 of the second release film 10 is not cured. During user use, fingerprints are easily formed when the user slides their fingers on the screen 7. Therefore, by curing the UV film 20 under the light-shielding area 102 of the second release film 10, the defect of fingerprints forming when sliding on the display screen can be avoided, and customer satisfaction can be further improved.

[0072] Optionally, the UV film 20 under the light-transmitting area 101 on the second release film 10 is first cured. At this time, the optical adhesive layer 6 in the display screen may be deformed, but it will not be cured because the deformed area is blocked. The display screen is left to stand for a preset time. If the optical adhesive layer 6 in the display screen is not deformed (i.e. the deformation is restored), the vacuum environment is removed and the second release film 10 is removed. Then the UV film 20 under the light-shielding area 102 is cured.

[0073] This method not only overcomes the technical defect of obvious top printing on the front caused by the simultaneous curing of UV film in different areas during the same period in the existing technology, but also overcomes the technical defect of fingerprints easily formed when sliding on the display screen, reducing the occurrence of top printing defects in mobile terminals and improving product quality and user satisfaction.

[0074] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0076] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0077] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "embodiment," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for applying a protective film, characterized in that, The protective film includes: First release film; A UV film, wherein the UV film is disposed on the first release film; and A second release film is disposed on the UV film. The second release film has a light-transmitting area and a light-shielding area, wherein the light-shielding area corresponds to the non-flat area under the display screen in the thickness direction of the display screen; the protective film application method includes the following steps: Remove the first release film and attach the UV film to the display screen; The UV film under the light-transmitting area on the second release film is cured in a vacuum environment; Remove the vacuum environment and remove the second release film; after removing the second release film, cure the UV film under the light-shielding area on the second release film.

2. The protective film application method according to claim 1, characterized in that, The protective film includes a planar area and a curved area. The light-shielding area is disposed on the planar area of ​​the second release film so as to completely block the planar area of ​​the second release film. The planar area corresponds to the planar display area on the display screen, and the curved area corresponds to the curved display area on the display screen.

3. The protective film application method according to claim 1 or 2, characterized in that, The light-shielding area is formed by blackening the second release film; and / or, the second release film is formed by splicing a light-shielding release film and a light-transmitting release film, wherein the position of the light-shielding release film corresponds to the position of the light-shielding area.

4. The protective film application method according to claim 3, characterized in that, The blackening process includes at least one of the following methods: lamination, printing, and spraying on the second release film.

5. The protective film application method according to claim 1, characterized in that, The non-flat area includes the joint step difference between the middle frame and / or the step difference where the device avoids obstacles.

6. The protective film application method according to claim 1, characterized in that, The uneven area includes the gold-plated foam auxiliary material area under the display screen.

7. The protective film application method according to claim 1, characterized in that, Before curing the UV film under the light-shielding area on the second release film, the display screen is left to stand for a preset time. If the optical adhesive layer in the display screen does not deform, the vacuum environment is then removed and the second release film is taken off.

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