CN220393597U - Protective film, display module assembly and electronic equipment - Google Patents

Abstract

The application provides a protection film, display module assembly and electronic equipment relates to electronic product technical field, solves the unable problem that has impact resistance effect and reduces the resilience force simultaneously of protection film. Specifically, the protection film includes base film layer and printing opacity glue film, and the printing opacity glue film includes first printing opacity glue film, and first printing opacity glue film range upon range of setting is in the base film layer, and the shear modulus of first printing opacity glue film is less than or equal to 25 kilopascals. The first light-transmitting adhesive layer can reduce rebound stress generated by deformation of the protective film in the folding process, so that a user can fold the protective film more easily when folding or unfolding the electronic equipment, and the user can open and close the electronic equipment with smaller force, so that the use experience of the user is improved.

Description

Protective film, display module assembly and electronic equipment

Technical Field

The application relates to the technical field of electronic products, in particular to a protective film, a display module and electronic equipment.

Background

Currently, with the development of electronic device technology, users have a higher and higher demand for electronic devices with large screens and convenient to carry, and thus, electronic devices with foldable display screens have been receiving a great deal of attention. The folding screen can be unfolded when in use, so that a larger display area is provided, and the folding screen is folded to a folding state when not in use, so that the folding screen is convenient for a user to carry.

The folding screen protective film can protect the display module from being damaged by external stress impact and external foreign matters, and the existing folding protective film product mainly comprises two types, namely, a hard transparent base film surface is additionally provided with a hardening layer, the scratch resistance is improved, and then the folding screen protective film is attached to a light-transmitting cover plate through OCA optical cement.

On the basis of the protective film, an elastic body with a buffer effect is arranged on the other side of the OCA optical adhesive, and the elastic body is connected with the light-transmitting cover plate through the other layer of the OCA optical adhesive, so that the impact damage resistance effect can be realized, and the screen can be effectively protected. However, the overall thickness of the protective film is greatly increased, when the bending radius of the folding screen is smaller, the stress on the display module is greatly enhanced in the bending process, so that the screen module has larger resilience after being bent and closed, the shell of the electronic equipment needs to be matched with larger magnet attraction force to prevent the screen from rebounding, and otherwise, the whole machine cannot be normally closed. Therefore, when a user opens the screen, the user needs to overcome the larger magnet attraction force, and the opening and closing use experience of the electronic equipment is affected. In summary, at present, a folding screen protection film scheme with an impact resistance effect and a resilience force reduction cannot be provided at the same time.

Disclosure of Invention

The embodiment of the application provides a protection film, display module assembly and electronic equipment for solve the unable problem that has impact resistance effect and reduce the resilience force simultaneously of protection film.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

in a first aspect, the present application provides a protective film for protecting a display screen, the protective film including a base film layer and a light-transmitting adhesive layer, the light-transmitting adhesive layer including a first light-transmitting adhesive layer, the first light-transmitting adhesive layer being laminated on the base film layer, the shear modulus of the first light-transmitting adhesive layer being less than or equal to 25 kpa. Shear modulus is a property that characterizes a material's ability to resist shear strain, with a greater shear modulus indicating a greater stiffness of the material. When the shear modulus of the first light-transmitting adhesive layer is within the above range, the rigidity of the protective film can be controlled within a reasonable range. Therefore, when the user folds or opens the electronic equipment, the protective film can be folded more easily, and the user can open and close the electronic equipment with smaller force, so that the use experience of the user is improved.

And the first light-transmitting glue layer is OCR liquid optical glue, and the OCR liquid optical glue also has certain elasticity. Therefore, when the flexible display screen is impacted by external force, the first light-transmitting adhesive layer can buffer certain stress, so that the flexible display screen is prevented from being damaged under the impact, and the flexible display screen is comprehensively and effectively protected. In addition, the first light-transmitting adhesive layer can reduce rebound stress generated by deformation of the protective film in the folding process, and prevent the protective film from bouncing and warping in the folding process of the flexible display screen

In summary, the mechanical property and the stronger pencil hardness of the protective film can be ensured by the base film layer, so that the protective film is not easy to scratch in the use process, the mechanical property of the protective film is ensured, the use reliability of the protective film is improved, and the display screen is comprehensively and effectively protected. In addition, the first light-transmitting adhesive layer can also improve the impact resistance of the protective film and reduce the resilience force when the screen is opened. When the user folds or opens the electronic equipment, the protection film is easier to fold, and the user can open and close the electronic equipment with smaller force, so that the use experience of the user is improved.

In one possible implementation manner of the first aspect, the shear modulus of the first light-transmitting glue layer is greater than or equal to 5 kpa. The rigidity requirement of the protective film is met, the requirement of protecting the flexible display screen is further met, the protective film has certain compressive strength, tensile strength and shear strength, and when the electronic equipment is folded, the protective film can be obviously deformed but is not damaged. The protection of the flexible display screen by the protective film is further improved, and the service life of the electronic equipment is prolonged.

In one possible implementation of the first aspect, the peel strength of the first light transmissive adhesive layer is greater than or equal to 550 grams force/inch. The protection film can be adhered to the surface of the light-transmitting cover plate through the first light-transmitting adhesive layer.

In a possible implementation manner of the first aspect, the protective film further includes a hardened layer, and the hardened layer is disposed on a surface of the base film layer facing away from the first transparent adhesive layer. The hardening layer can be well attached to the surface of the base film layer, can be used as a functional layer to be formed on the priming layer of the surface of the base film layer, improves the adhesive force of the functional layer on the surface of the base film layer, avoids easy stripping between the functional layer and the base film layer, and improves the use reliability of the protective film. In this embodiment, the hardened layer is taken as an acrylic resin as an example, and the hardened layer made of the acrylic resin has higher hardness, and can also provide mechanical support for the functional layer located outside the hardened layer, so as to ensure the wear resistance of the protective film. Physical damage to the protective film, including scratch, abrasion, impact and the like, can be reduced when the protective film is used by consumers, and further the use experience of the users is improved.

In a possible implementation manner of the first aspect, the light-transmitting glue layer further includes a second light-transmitting glue layer, and the second light-transmitting glue layer is stacked on a surface of the first light-transmitting glue layer facing away from the base film layer; the second light-transmitting adhesive layer is OCA optical adhesive. The protective film is adhered to the surface of the light-transmitting cover plate through a second light-transmitting adhesive layer, the second light-transmitting adhesive layer is OCA optical adhesive, the OCA optical adhesive is prepared by making acrylic acid glue into a base material-free adhesive tape, and then a release film is respectively adhered to the upper bottom layer and the lower bottom layer to obtain the double-sided adhesive tape without a base material. The OCA optical adhesive has the advantages of high cleanliness, high light transmittance, low haze and the like, has higher adhesiveness, and can firmly adhere the protective film to the surface of the light-transmitting cover plate, so that the use reliability of the protective film is improved. The OCA optical adhesive is double-sided adhesive, the thickness is more uniform, the flatness is higher, and the protection film is adhered by the OCA optical adhesive, so that the flatness of the flexible display screen is improved.

In a possible implementation manner of the first aspect, the optical fiber further includes an elastic layer, and the elastic layer is stacked between the first light-transmitting adhesive layer and the second light-transmitting adhesive layer. The elastic layer has certain elasticity, when the flexible display screen is impacted by external force, the elastic layer can buffer the impact of the external force, so that the flexible display screen is protected, and the flexible display screen is prevented from being damaged under the impact of the external force. In some embodiments, the elastic layer is a thermoplastic polyurethane structure or a silicone structure. In this embodiment, an elastic layer is taken as an example of a thermoplastic polyurethane structure, and the thermoplastic polyurethane structure has good elasticity, low cost and good mechanical strength. The processing method can be used for processing the resin into solution through injection, extrusion, calendaring, dissolution and the like, and has good processing performance.

In one possible implementation manner of the first aspect, the elastic layer is a thermoplastic polyurethane structure or a silicone structure.

In a possible implementation manner of the first aspect, the light-transmitting layer further includes a functional layer, and the functional layer is stacked on a surface of the hardened layer, which is away from the first light-transmitting adhesive layer; the functional layer is one or more of an antireflection layer, an anti-dazzle layer and an anti-fingerprint layer. The anti-reflection layer can improve the transmittance of light on the surface of the protective film, reduce the reflectivity of the light on the surface of the protective film, ensure the anti-reflection effect of the protective film, reduce the influence of the protective film on the display definition of the flexible display screen and improve the use feeling of a user. The glare is a bad lighting phenomenon, when the brightness of the light source is extremely high or the brightness difference between the background and the center of the visual field is large, the glare is generated, and the anti-glare layer can reduce the bad influence caused by the glare. The anti-fingerprint layer can prevent the flexible display screen from being polluted by dust and grease, reduce the adhesion of fingerprints and improve the cleanliness of products. The antistatic layer has antistatic property, reduces the surface resistance of the protective film, prevents static electricity from generating, ensures the antistatic property of the protective film, avoids the adsorption of dust and impurities generated on the surface of the protective film, and improves the display quality of the display screen when the protective film is adhered to the flexible display screen.

In one possible implementation manner of the first aspect, the creep resilience of the first light-transmitting glue layer is greater than or equal to 85%.

In one possible implementation of the first aspect, the cohesive strength of the first light transmissive adhesive layer is greater than or equal to 1.5 n/cm.

In one possible implementation manner of the first aspect, the first light-transmitting glue layer is one or more of a silicone structure, a polyacrylate structure, an epoxy structure, and a polyurethane structure.

In one possible implementation of the first aspect, the protective film has a thickness of less than or equal to 160 micrometers. The thickness of the protective film is in the range, so that the light and thin flexible display screen can be ensured, the folding of the flexible display screen is facilitated, and the use experience of a user is improved.

In a second aspect, the application further provides a display module, the display module includes a display panel, a light-transmitting cover plate and the protective film, the display panel includes a display surface, and the light-transmitting cover plate is stacked on the display surface. The protection film lamination sets up in the light-transmitting apron and deviates from display panel's surface.

In a possible implementation manner of the second aspect, the display module is a flexible display module.

Because the display module provided by the embodiment of the application comprises the protective film according to any technical scheme, the display module and the protective film can solve the same technical problem and achieve the same effect.

In a third aspect, the application further provides an electronic device, which includes a housing and the display module, where the display module is disposed in the housing.

Because the electronic equipment provided by the embodiment of the application comprises the display module according to any technical scheme, the electronic equipment and the display module can solve the same technical problem and achieve the same effect.

Drawings

Fig. 1 is a perspective view of an electronic device provided in some embodiments of the present application;

FIG. 2 is a block diagram of a semi-folded state of an electronic device provided in some embodiments of the present application;

fig. 3 is a block diagram of a folded state of an electronic device according to some embodiments of the present application;

FIG. 4 is a schematic cross-sectional view of the flexible display screen of FIG. 1 taken along line A-A;

fig. 5 is a schematic structural diagram of a protective film according to some embodiments of the present disclosure;

fig. 6 is a block diagram of a semi-folded state of a protective film provided in some embodiments of the present application;

FIG. 7 is a graph comparing the rebound moment of a protective film provided in some embodiments of the present application with that of a conventional protective film when folded;

FIG. 8 is a schematic view of a protective film according to further embodiments of the present application;

FIG. 9 is a schematic view of a protective film according to further embodiments of the present application;

FIG. 10 is a schematic view of a protective film according to further embodiments of the present application;

fig. 11 is a schematic structural view of a protective film according to still other embodiments of the present application.

Reference numerals

100. An electronic device; 10. a flexible display screen; 11. a light-transmitting cover plate; 12. a display panel; 13. a support plate;

14. a protective film; 141. a base film layer; 142. a light-transmitting adhesive layer; 1421. a first light-transmitting adhesive layer; 1422. a second light-transmitting adhesive layer; 143. a hardening layer; 144. an elastic layer; 145. a functional layer;

101. a first display area; 102. a second display area; 103. a third display area;

20. a housing; 21. a first housing; 211. a first front case; 212. a first rear cover; 213. a driving chip;

22. a second housing; 221. a second front case; 222. a second rear cover; 23. and (5) a hinge.

Detailed Description

In some embodiments, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", "a third", and "a fourth" may explicitly or implicitly include one or more such feature.

In some embodiments, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

It is to be understood that the above orientation or positional relationship as indicated by the terms "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description and to simplify the description, and are not indicative or implying that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present utility model; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

The application provides an electronic device which is a type of electronic device with a folding display screen. The electronic device may be a User Equipment (UE) or a terminal device (terminal) or the like. For example, the electronic device may be a Personal Digital Assistant (PDA), a handheld device with wireless communication function, a computing device, an in-vehicle device, a wearable device, a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a terminal in industrial control (industrial control), a terminal in unmanned (self driving), a terminal in remote medical (remote), a terminal in smart grid (smart grid), a terminal in transportation security (transportation security), a terminal in smart city (smart city), a terminal in smart home (smart home). The large-screen display terminal includes, but is not limited to, devices such as a smart screen, a tablet Pc (PAD), a notebook computer, a desktop computer, a television, and a projector.

Referring to fig. 1, fig. 1 is a perspective view of an electronic device 100 according to some embodiments of the present application. The present embodiment and the following embodiments are exemplary illustrations using the electronic device 100 as a mobile phone. The electronic device 100 is approximately rectangular plate-like. On this basis, in order to facilitate the description of the embodiments below, an XYZ coordinate system is established, the width direction of the electronic apparatus 100 is defined as the X-axis direction, the length direction of the electronic apparatus 100 is defined as the Y-axis direction, and the thickness direction of the electronic apparatus 100 is defined as the Z-axis direction. It is to be understood that the coordinate system of the electronic device 100 may be flexibly set according to actual needs, which is not specifically limited herein. In other embodiments, the shape of the electronic device 100 may be a square flat plate, a round flat plate, an oval flat plate, or the like, which is not particularly limited herein.

With continued reference to fig. 1, the electronic device 100 includes a housing 20 and a flexible display 10, the flexible display 10 being coupled to the housing 20. The housing 20 may include a first housing 21, a second housing 22, and a hinge 23. The first housing 21 and the second housing 22 are located on both sides of the hinge 23, respectively. The first housing 21 and the second housing 22 are connected to a hinge 23, respectively. For example, the first housing 21 and the second housing 22 may be connected to the hinge 23 by welding or fastening, respectively.

Referring to fig. 2 and fig. 3, fig. 2 is a block diagram of a semi-folded state of the electronic device 100 according to some embodiments of the present application, and fig. 3 is a block diagram of a folded state of the electronic device 100 according to some embodiments of the present application. The first housing 21 and the second housing 22 are rotatable and foldable with respect to the hinge 23, respectively. When the first casing 21 and the second casing 22 are close to each other and stacked on each other, the electronic apparatus 100 is in a folded state. The first casing 21 and the second casing 22 are away from each other from the stacked state, and when the first casing 21 and the second casing 22 are rotated to be unable to rotate, the electronic apparatus 100 is in the unfolded state. The process of the first housing 21 and the second housing 22 from the folded state to the unfolded state is an unfolding process, and the process of the first housing from the unfolded state to the folded state is a folding process. Illustratively, the number of first housings 21 and second housings 22 may each be one. When the electronic apparatus 100 is in the folded state, the first casing 21 and the second casing 22 are laminated to take on a two-layer structure.

The flexible display screen 10 is used to display images, videos, and the like. The flexible display screen 10 includes a first display area 101, a second display area 102, and a third display area 103. The first display area 101 is provided corresponding to the first housing 21. The second display area 102 is disposed corresponding to the second housing 22. The third display area 103 is provided corresponding to the hinge 23. The flexible display screen 10 has bending property and can deform under the action of external force. When the first housing 21 and the second housing 22 are in the folded state, the flexible display screen 10 is in the folded state. The first display area 101 and the third display area 103 of the flexible display screen 10 are close to each other, and the third display area 103 may be bent into an arc state. When the first housing 21 and the second housing 22 are in the unfolded state, the flexible display screen 10 is in the unfolded state, so that the first display area 101, the second display area 102, and the third display area 103 take on a flat state.

When in the unfolded state shown in fig. 1, the electronic device 100 can realize large-screen display, so as to provide richer information for a user and bring better use experience for the user. When the electronic device 100 is in the folded state shown in fig. 3, the electronic device 100 is reduced in size and convenient to carry.

It should be noted that, the electronic device 100 shown in fig. 3 is an inwardly folded display device, that is, when the electronic device 100 is in a folded state, the housing 20 is protected outside the flexible display screen 10, and the flexible display screen 10 is not visible to the user, so that the flexible display screen 10 can be prevented from being scratched by a hard object. In other embodiments, the electronic device 100 may be an out-folded display device, that is, when the electronic device 100 is in a folded state, the flexible display screen 10 is located on the outer side of the housing 20, and the flexible display screen 10 is visible to a user, so that video and image display can be realized in the folded state. The following embodiments are descriptions based on the electronic device 100 being an invaginated display device, and this should not be construed as a particular limitation on the structural configuration of the electronic device 100.

Referring to fig. 4, fig. 4 is a schematic cross-sectional structure of the electronic device of fig. 1 along line A-A. The first housing 21 may include a first front case 211 and a first rear cover 212 coupled together. The second housing 22 may include a second front case 221 and a second rear cover 222 coupled together. The hinge 23 is connected between the first front case 211 and the second front case 221. A part of the flexible display screen 10 is carried on the first front case 211, a part is carried on the second front case 221, and the other part is carried on the hinge 23. The first rear cover 212 is located at a side of the first front case 211 away from the flexible display screen 10, and a first receiving space C1 is formed between the first rear cover 212 and the first front case 211. The second rear cover 222 is located at a side of the second front case 221 away from the flexible display screen 10, and a second receiving space C2 is formed between the second rear cover 222 and the second front case 221. The first accommodating space C1 and the second accommodating space C2 are used for accommodating electronic components such as a motherboard, a subplate, a speaker module, a camera module, a battery, and the like. In addition, referring to fig. 4, a driving chip 213 is further disposed on a surface of the first front case 211 facing the flexible display screen 10, and the driving chip 213 is used for driving the flexible display screen 10 to display. In other embodiments, the driving chip 213 may also be disposed on a surface of the second front case 221 facing the flexible display screen 10. In this embodiment, it should be noted that the first back cover 212 and the second back cover 222 may also be replaced by a display screen (such as a liquid crystal display screen), so that the foldable display device 100 still has the functions of displaying video and images in the folded state.

With continued reference to fig. 4, the structure of the flexible display 10 is described in detail below. The flexible display screen 10 includes a light-transmitting cover plate 11, a display panel 12, and a support plate 13, which are stacked.

It will be appreciated that fig. 4 schematically illustrates some of the film layers included in the flexible display screen 10, and the size and structure of the film layers are not limited by fig. 4, and the flexible display screen 10 may include other film layers besides those film layers, such as a polarizer, a buffer layer, a shielding layer, and the like, which are not specifically limited herein.

The transparent cover plate 11 is used for protecting the display panel 12 from water, dust and scratch. The material of the transparent cover plate 11 includes, but is not limited to, plastic. In other embodiments, the flexible display screen 10 may not be provided with the light-transmitting cover plate 11.

The display panel 12 is a main component for displaying images and videos. Specifically, the display panel 12 may be an organic light-emitting diode (OLED) display panel, a micro-organic light-emitting diode (micro organiclight-emitting diode) display panel, or a quantum dot light-emitting diode (quantumdotlight emittingdiode, QLED) display panel. The display panel 12 has a display side and a back side opposite the display side. The display side of the display panel 12 refers to the side of the display panel 12 that displays images or videos, from which a user can view the images or videos displayed by the display panel 12. The light-transmitting cover plate 11 is located on the display side.

The support plate 13, also called a "bamboo book", is located on the back side of the display panel 12. The support plate 13 plays a supporting role for the display panel 12. On this basis, the supporting plate 13 is made of metal such as stainless steel and titanium alloy, and the metal has a certain hardness and a large elastic modulus, so that the hardness and bending resilience of the flexible display screen 10 can be improved.

During use of the electronic device 100, the flexible display 10 may be subject to scratches, abrasion, or drop cracking. To avoid damage to the flexible display 10 during use, the flexible display 10 further includes a protective film 14, where the protective film 14 is stacked on a surface of the light-transmitting cover plate 11 facing away from the display panel 12, for protecting the flexible display 10. The size of the protective film 14 may be the same as the size of the light-transmitting cover plate 11 or slightly larger than the size of the light-transmitting cover plate 11. Here, the fact that the protective film 14 is slightly larger than the size of the light-transmitting cover plate 11 means that the length and width of the protective film 14 are not more than 1mm larger than the length and width of the light-transmitting cover plate 11. The part of the protective film 14 larger than the transparent cover plate 11 can be folded towards the transparent cover plate 11 to wrap the peripheral side wall of the transparent cover plate 11, so that the flexible display screen 10 is protected in all directions.

Referring to fig. 5, fig. 5 is a schematic structural diagram of a protective film 14 according to some embodiments of the present application. The protective film 14 includes a base film layer 141 and a light-transmitting adhesive layer 142. Specifically, the base film layer 141 is laminated on the surface of the transparent cover plate 11 facing away from the display panel 12, and the transparent adhesive layer 142 includes a first transparent adhesive layer 1421, where the first transparent adhesive layer 1421 is laminated on the surface of the base film layer 141 facing away from the transparent cover plate 11. The material of the base film layer 141 may be polyethylene terephthalate (polyethylene terephthalate, PET), polycarbonate (PC), or polymethyl methacrylate (PMMA). The base film layer 141 can improve the hardness and smoothness of the flexible protective film 14 and enhance the surface damage resistance. The material of the base film layer 141 is not limited to the above, and may be other materials suitable for a thin film having the above properties. In this embodiment and the following embodiments, the base film layer 141 is exemplified by a polyethylene terephthalate plastic, which is a base material layer of the protective film 14 for protecting the screen, and has a high hardness, and can provide the protective film 14 with high abrasion resistance and high scratch resistance. The further polyethylene terephthalate plastic selects the base film layer 141 with the transmittance of more than or equal to 90% and the haze of less than or equal to 1% in the 550nm wave band, so that the protective film 14 has good light transmittance.

The first light-transmitting glue layer 1421 may be an OCA optical glue, which has the characteristics of colorless transparency, light transmittance of more than 95%, good cementing strength, being curable at room temperature or medium temperature, small curing shrinkage, and the like. Referring to fig. 6, fig. 6 is a schematic diagram illustrating a half-folded state of the protective film 14 according to some embodiments of the present application. Because the OCA optical adhesive has a larger elastic modulus, when the electronic device 100 is folded, the stress that causes a certain elastic deformation of the flexible display screen 10 is also larger, that is, the rigidity of the flexible display screen 10 is larger. As described with reference to fig. 6, during folding of the electronic device 100, the user is required to apply the force F11 and the force F12 to the first case 21 and the second case 22 close to each other, and the opposing force F2 of the force F11 and the force F12 of the first light-transmitting adhesive layer 1421 is high due to the high elastic modulus of the OCA optical adhesive. Thus, the user needs to apply more force to fold the electronic device 100. After the electronic device 100 is folded, in order to avoid that the electronic device 100 bounces open under its own elasticity, magnets that attract each other are provided on the first display area 101 and the second display area 102, and the first display area 101 and the second display area 102 are stacked together by the attraction of the magnets. Because the OCA optical adhesive has a higher elastic modulus, the electronic device 100 needs to be provided with a magnet with a larger attraction force, so as to avoid the automatic opening of the flexible display screen 10. In this way, when the user uses the electronic device 100, a force greater than the attraction force of the magnet is also required to open the flexible display screen 10, which greatly reduces the user experience.

To address the above, some embodiments are also provided herein in which the OCA optical paste is replaced with an OCR liquid optical paste, that is, the first light transmissive adhesive layer 1421 is set to an OCR liquid optical paste, and the shear modulus of the OCR liquid optical paste is set to be less than or equal to 25 kpa. Shear modulus is a property that characterizes a material's ability to resist shear strain, with a greater shear modulus indicating a greater stiffness of the material. When the electronic device 100 is folded, the third display area 103 of the flexible display 10 receives a shearing force from the force F11 and the force F12, and the shearing force is a force applied to adjacent portions of the same object in two directions, so that the two portions are relatively displaced in respective directions of force. When the shear modulus of the first light-transmitting adhesive layer 1421 is within the above range, the rigidity of the protective film 14 can be controlled within a reasonable range. In this way, when the user folds or unfolds the electronic device 100, the protective film 14 can be folded more easily, and the user can open and close the electronic device 100 with less force, so as to improve the user experience.

The first light-transmitting adhesive layer 1421 is an OCR liquid optical adhesive, and the OCR liquid optical adhesive itself has a certain elasticity. Therefore, when the flexible display screen 10 is impacted by external force, the first transparent adhesive layer 1421 can also buffer certain stress, so that the flexible display screen 10 is prevented from being damaged under impact, and the flexible display screen 10 is comprehensively and effectively protected. In addition, the first transparent adhesive layer 1421 can reduce the rebound stress generated by the deformation of the protective film 14 during the folding process, and prevent the protective film 14 from bouncing and tilting during the folding process of the flexible display screen 10.

In summary, the base film 141 can ensure the mechanical properties and the relatively strong pencil hardness of the protective film 14, so that the protective film 14 is not easily scratched during use, the mechanical properties of the protective film 14 are ensured, and the use reliability of the protective film 14 is improved. The display screen is comprehensively and effectively protected. In addition, the first light-transmitting adhesive layer 1421 can also improve the impact resistance of the protective film 14 and can reduce the repulsive force at the time of screen opening. When the user folds or unfolds the electronic device 100, the protective film 14 is easier to fold, and the user can open and close the electronic device 100 with less force, thereby improving the user experience.

Referring to fig. 7, fig. 7 is a diagram showing a comparison of the rebound moment of the protective film 14 provided in some embodiments of the present application and the rebound moment of the conventional protective film when folded. The X-axis in the drawing shows the bending angle of the protective film 14, and the Y-axis shows the rebound moment of the protective film 14 with bending, the rebound moment being shown in units of cow/meter. The solid line in the figures represents the existing protective film's rebound torque curve and the dash-dot line represents the protective film 14's rebound torque curve provided by some embodiments of the present application. When the electronic device 100 is folded, the protective film 14 provided in some embodiments of the present application and the existing protective film are bent at the same angle, and the protective film 14 provided in some embodiments of the present application generates a smaller rebound moment than the existing protective film. Therefore, the user can open and close the electronic device 100 with less force, improving the user experience.

Further, based on the above embodiment, the shear modulus of the first transparent adhesive layer 1421 is greater than or equal to 5 kpa, so as to meet the rigidity requirement of the protective film 14, and further meet the requirement of protecting the flexible display screen 10, and the protective film 14 has a certain compressive strength, tensile strength and shear strength, and can be obviously deformed but not damaged when the electronic device 100 is folded. The protection of the flexible display 10 by the protective film 14 is further improved, and the service life of the electronic device 100 is prolonged.

In some embodiments, the thickness of the first light transmissive adhesive layer 1421 is greater than or equal to 5 microns and less than or equal to 75 microns. When the thickness of the first transparent adhesive layer 1421 is within the above range, the thickness of the flexible display screen 10 can be ensured to be light and thin, which is also beneficial to folding the flexible display screen 10, so as to improve the use experience of the user.

In some embodiments, the creep spring-back of the first light transmissive adhesive layer 1421 is greater than or equal to 85%. The creep resilience of the first light-transmitting adhesive layer 1421 was measured, and a creep test was performed using a rheometer, to prepare an original sheet-like sample having a diameter of 8mm and a thickness of 1mm, and after a constant shear stress of 20kpa was applied to the rheometer for 10 minutes, the creep deformation 1 was recorded, and then the shear stress was completely removed and left to stand for 10 minutes, and the residual creep deformation 2 was recorded, and the creep resilience= (creep deformation 1-creep deformation 2)/creep deformation 1x100%.

In some embodiments, the cohesive strength of the first light transmissive adhesive layer 1421 is greater than or equal to 1.5 n/cm. Cohesive force is the interconnecting force between atoms or molecules of a material, and the solid is not broken by being connected together, namely, the cohesive force. The cohesive strength refers to a strength that the first light-transmitting glue layer 1421 can withstand the maximum external force without damaging itself. When the cohesive strength of the first light-transmitting glue layer 1421 is within the above strength range, the first light-transmitting glue layer 1421 has better mechanical properties, so that the use reliability of the protective film 14 is improved, and the use experience of a user is further improved. The interlayer peel strength of the first light-transmitting adhesive layer 1421 after the double-sided adhesive of the 25 μm polyester film is defined as the cohesive strength of the first light-transmitting adhesive layer 1421, and the cohesive strength test method of the first light-transmitting adhesive layer 1421 is as follows: the 25-micrometer polyester film is coated with a first transparent optical glue after plasma treatment, another layer of completely consistent plasma-treated 25-micrometer polyester film is coated on the other surface after curing, one surface of the film is fixed on a standard steel plate by using a high-adhesion adhesive tape according to the test standard GB/T2792-2014, and 180-degree peeling test is carried out to measure the interlayer peeling strength.

In some embodiments, the material of the first light transmissive adhesive layer 1421 may include one or more of silicone, polyacrylate, epoxy, polyurethane. The first light-transmitting adhesive layer 1421 may be formed by a coating method or a deposition method. The coating method is to coat the liquid first transparent glue layer 1421 on the surface of the base film layer 141 by roller coating or spraying, and then cure and reinforce the hardness of the first transparent glue layer 1421 to form the solid first transparent glue layer 1421.

The deposition method includes physical deposition or chemical deposition, performing physical or chemical treatment on the gaseous substance, depositing a layer of first transparent glue layer 1421 in a liquid phase state on the surface of the base film layer 141, and then curing to form the first transparent glue layer 1421. In this embodiment, the first transparent adhesive layer 1421 is formed between the base film layer 141 and the transparent cover 11 by coating. The first light-transmitting glue layer 1421 is directly formed on the surface of the light-transmitting cover plate 11 in two ways, bonding and lamination are not needed by adopting modes such as optical glue, the base film layer 141 is bonded on the surface of the light-transmitting cover plate 11 through the first light-transmitting glue layer 1421, and the peeling strength of the first light-transmitting glue layer 1421 is greater than or equal to 550 gram force/inch. So that the OCA optical adhesive can be prevented from generating larger internal stress between the base film 141 and the first transparent adhesive layer 1421, and the adhesion of the base film 141 can be ensured.

The test method of the peel strength of the first light-transmitting adhesive layer is described in GB/T2792-2014 with reference to method 3: the test method of 180 DEG peel strength of the double-sided adhesive tape and the transfer adhesive tape with the stainless steel plate was performed.

Referring to fig. 8, fig. 8 is a schematic structural diagram of a protective film 14 according to still other embodiments of the present application. The protective film 14 further includes a cured layer 143, where the cured layer 143 is stacked on a surface of the base film 141 facing away from the first transparent adhesive layer 1421. The material of the hardening layer 143 includes an acrylate material, a PUA material, a silane modified acrylate material, or a silane modified PUA material. The hardened layer 143 can be well attached to the surface of the base film 141, and can also be used as a primer layer for forming the functional layer 145 on the surface of the base film 141, so as to improve the adhesion of the functional layer 145 on the surface of the base film 141, avoid easy peeling between the functional layer 145 and the base film 141, and improve the reliability of the protective film 14. In the present embodiment, the hardened layer 143 is exemplified by acrylic resin, and the hardened layer 143 made of acrylic resin has high hardness, and can also provide mechanical support for the functional layer 145 located outside the hardened layer 143, thereby ensuring the wear resistance of the protective film 14. Physical damage to the protective film 14 including scratch, abrasion, impact, etc. during use by the consumer can be reduced, thereby improving the use experience of the user.

Referring to fig. 9, fig. 9 is a schematic structural diagram of a protective film 14 according to still other embodiments of the present application. In some embodiments, the light-transmitting glue layer further includes a second light-transmitting glue layer 1422, where the second light-transmitting glue layer 1422 is stacked on the surface of the first light-transmitting glue layer 1421 facing away from the base film layer 141. The second light-transmitting adhesive layer 1422 is an OCA optical adhesive. In the present embodiment, compared with the above embodiment, the peel strength of the first transparent adhesive layer 1421 is not limited, that is, in the present embodiment, the first transparent adhesive layer 1421 may not have an adhesive effect, and only the requirement of buffering stress is satisfied. The protective film 14 is adhered to the surface of the transparent cover plate 11 through a second transparent adhesive layer 1422, the second transparent adhesive layer 1422 is OCA optical adhesive, the OCA optical adhesive is a double-sided adhesive tape without a matrix material, which is obtained by making acrylic glue into a base material-free material, and then respectively attaching a release film to the upper and lower bottom layers. The OCA optical adhesive has the advantages of high cleanliness, high light transmittance, low haze and the like, has higher adhesiveness, and can firmly adhere the protective film 14 to the surface of the light-transmitting cover plate 11, thereby improving the use reliability of the protective film 14. The OCA optical adhesive is a double-sided adhesive, has more uniform thickness and higher flatness, and is also beneficial to improving the flatness of the flexible display screen 10 by adhering the protective film 14 through the OCA optical adhesive.

Referring to fig. 10, fig. 10 is a schematic structural diagram of a protective film 14 according to still other embodiments of the present application. On the basis of the above embodiment, the protective film 14 further includes an elastic layer 144, where the elastic layer 144 is stacked between the first transparent adhesive layer 1421 and the second transparent adhesive layer 1422. The elastic layer 144 has certain elasticity, when the flexible display screen 10 is impacted by external force, the elastic layer 144 can buffer the impact of the external force, and then the flexible display screen 10 is protected, so that the flexible display screen 10 is prevented from being damaged under the impact of the external force. In some embodiments, the elastic layer 144 is a thermoplastic polyurethane structure or a silicone structure. In this embodiment, the elastic layer 144 is exemplified by a thermoplastic polyurethane structure, which has good elasticity, low cost, and good mechanical strength. The processing method can be used for processing the resin into solution through injection, extrusion, calendaring, dissolution and the like, and has good processing performance.

Referring to fig. 11, fig. 11 is a schematic structural diagram of a protective film 14 according to still other embodiments of the present application. The protective film 14 further includes a functional layer 145, where the functional layer 145 is stacked on a surface of the hardened layer 143 facing away from the first transparent adhesive layer 1421. In particular, the functional layer 145 may be one or more of an anti-reflection layer, an anti-glare layer, an anti-fingerprint layer, and an anti-static layer. The antireflection layer can improve the transmittance of light on the surface of the protective film 14, reduce the reflectivity of light on the surface of the protective film 14, ensure the antireflection effect of the protective film 14, reduce the influence of the protective film 14 on the display definition of the flexible display screen 10, and improve the use feeling of a user. The glare is a bad lighting phenomenon, when the brightness of the light source is extremely high or the brightness difference between the background and the center of the visual field is large, the glare is generated, and the anti-glare layer can reduce the bad influence caused by the glare. The fingerprint-resistant layer can prevent the flexible display screen 10 from being polluted by dust and grease, reduce the adhesion of fingerprints and improve the cleanliness of the product. The antistatic layer has antistatic property, reduces surface resistance of the protective film 14, prevents static electricity from being generated, ensures antistatic property of the protective film 14, prevents dust and impurities from being adsorbed on the surface of the protective film 14, and improves display quality of the display screen when the protective film 14 is adhered to the flexible display screen 10.

In some embodiments, the thickness of the protective film 14 is less than or equal to 160 micrometers, and the thickness of the protective film 14 is within the above range, so that the flexible display screen 10 can be ensured to be light and thin, and folding of the flexible display screen 10 is facilitated, so that the use experience of a user is improved.

In the description of the present specification, a particular feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments or examples.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims (14)

1. A protective film for protecting a display screen, comprising:

a base film layer;

the light-transmitting adhesive layer comprises a first light-transmitting adhesive layer, the first light-transmitting adhesive layer is arranged on the base film layer in a stacked mode, and the shear modulus of the first light-transmitting adhesive layer is less than or equal to 25 kilopascals;

the second light-transmitting adhesive layer is arranged on the surface, away from the base film layer, of the first light-transmitting adhesive layer in a stacked mode;

the elastic layer is arranged between the first light-transmitting adhesive layer and the second light-transmitting adhesive layer in a layer-by-layer mode.

2. The protective film of claim 1, wherein the first light transmissive adhesive layer has a shear modulus of greater than or equal to 5 kilopascals.

3. The protective film of claim 1 or 2, wherein the first light transmissive adhesive layer has a peel strength of greater than or equal to 550 grams force/inch.

4. The protective film according to claim 1 or 2, further comprising a stiffening layer disposed over a surface of the base film layer facing away from the first light transmissive adhesive layer.

5. The protective film according to claim 1 or 2, wherein the second light-transmitting adhesive layer is an OCA optical adhesive.

6. The protective film according to claim 1 or 2, wherein the elastic layer is a thermoplastic polyurethane structure or a silicone structure.

7. The protective film of claim 4, further comprising a functional layer disposed on a surface of the hardened layer facing away from the first light transmissive adhesive layer; the functional layer is one or more of an anti-reflection layer, an anti-dazzle layer and an anti-fingerprint layer.

8. The protective film of claim 1 or 2, wherein the first light transmissive adhesive layer has a creep spring-back of greater than or equal to 85%.

9. The protective film of claim 1 or 2, wherein the cohesive strength of the first light transmissive adhesive layer is greater than or equal to 1.5 n/cm.

10. The protective film according to claim 1 or 2, wherein the first light-transmitting adhesive layer is a silicone structure, a polyacrylate structure, an epoxy structure, or a polyurethane structure.

11. The protective film according to claim 1 or 2, wherein the protective film has a thickness of 160 micrometers or less.

12. A display module, comprising:

a display panel including a display surface;

the light-transmitting cover plate is arranged on the display surface in a stacked mode;

the protective film of any one of claims 1-11, wherein the protective film is disposed on a surface of the light-transmissive cover plate facing away from the display panel.

13. The display module of claim 12, wherein the display module is a flexible display module.

14. An electronic device, comprising:

a housing;

the display module of claim 12 or 13, disposed within the housing.