Display screen, display module and electronic equipment

Abstract

The invention discloses a display screen, a display module and electronic equipment, and relates to the technical field of display modules, the display screen comprises a display panel and a back film which are connected in a stacked mode, the back film is made of a thermoplastic material, the glass transition temperature of the thermoplastic material ranges from 60 DEG C to 120 DEG C, and the glass transition temperature of the thermoplastic material ranges from 60 DEG C to 120 DEG C. The Young modulus of the thermoplastic material for preparing the back film in the elastic state is smaller than or equal to 800 MPa, and the Young modulus of the thermoplastic material for preparing the back film in the glassy state is larger than 1000 MPa. The material of the back film is limited to be the thermoplastic material, so that the Young modulus of the back film can be reduced in the side edge hot bending process of the display screen, the display screen can be better bent, the surface layer and the back film cannot strongly extrude the display panel, and the display screen is prevented from being damaged in the hot bending process.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a display screen, a display module, and an electronic device. Background Art

[0002] In order to improve the delicacy and grip feeling of the display screen, the display screens of electronic devices increasingly adopt a design with a curved edge. By applying a downward pressure on the edge, the edge area is bent to form a curved-edge curved screen. Currently, curved-screen electronic devices mostly adopt flexible organic light-emitting diode (OLED) display modules. Generally, a flat display screen is first prepared, including a stacked cover glass (CG), optically clear adhesive (OCA), polarizer (POL), display and touch layer (PANEL), back film (BF), silica gel (SEPA), and the support structure at the bottom layer.

[0003] When preparing the curved screen, usually the flat cover glass, optically clear adhesive, polarizer, display and touch layer, back film, silica gel, and the support structure at the bottom layer are connected, and a certain pressure is applied to the edge of the cover glass for bending. During this process, due to the certain hardness of the back film, it will squeeze the display and touch layer together with the cover glass, and the display and touch layer is prone to wrinkles in the bending area, and these wrinkles are particularly obvious in the corner bending area. Summary of the Invention

[0004] This application provides a display screen, a display module, and an electronic device. By defining that the back film in the display screen is made of a thermoplastic material, it is beneficial to the bending preparation of the display screen and improves the yield rate of the curved display screen.

[0005] In a first aspect, this application provides a display screen, including a display panel and a back film connected in a stacked manner. The material of the back film includes a thermoplastic material. The glass transition temperature of the thermoplastic material is in the range of 60 degrees Celsius to 120 degrees Celsius. The Young's modulus of the thermoplastic material in the elastic state is less than or equal to 800 MPa, and the Young's modulus of the thermoplastic material in the glass state is greater than 1000 MPa.

[0006] In the embodiments of this application, by defining that the material of the back film is a thermoplastic material, during the hot bending process of the display screen, the transition from the glass state to the elastic state can be completed. At the same time, due to the decrease in the Young's modulus of the back film during the transition process, plastic deformation can easily occur, reducing the force on the display panel, so that the display screen can be bent better, avoiding wrinkles on the display panel in the corners, and preventing the display screen from being damaged during the hot bending process.

[0007] In some feasible implementation manners, the thermoplastic material includes at least one of polycarbonate, polyvinyl butyral, polypropylene, polyethylene, and polymethyl methacrylate. The above materials can reduce their glass transition temperatures by changing the molecular weight, so that the glass transition temperatures of the above materials are in the range of 60 °C to 120 °C, and have a relatively small Young's modulus during the thermoforming process of the display screen, which is beneficial to the thermoforming of the display screen.

[0008] In some feasible implementation manners, the back film includes at least two layers of back films arranged in a stack, and the at least two layers of back films include a first back film, and the material of the first back film is the thermoplastic material; the back film can have multiple layers and form a multi-layer stack structure. While reducing the Young's modulus of the back film during the thermoforming process of the display screen, shear slip can also occur between the multiple layers of back films, which is beneficial to reducing the stress on the display panel. The material of any one of the at least two layers of back films can be the thermoplastic material. The multiple layers of back films are all supported by the thermoplastic material, which is convenient for increasing the shear slip of the thermoplastic material layers during thermoforming and is beneficial to reducing the stress on the display panel.

[0009] In some feasible implementation manners, the at least two layers of back films include a second back film, and the materials of the first back film and the second back film are different thermoplastic materials. The back film can be a composite layer composed of multiple different types of thermoplastic materials. For example, the back film can be a composite layer formed by stacking three layers of back films made of acrylate + polycarbonate + polyurethane.

[0010] In some feasible implementation manners, the display screen further includes a first connection layer, and the material of the first connection layer includes a pressure-sensitive material. The first connection layer is located between the display panel and the back film and fixedly connects the display panel and the back film. The Young's modulus of the pressure-sensitive adhesive material is about 25 kPa at the thermoforming temperature and about 160 kPa at the room temperature after cooling. Under the high-temperature conditions during thermoforming, the Young's modulus is small to reduce the bonding stress between the first connection layer and the display panel and the back film respectively, which is convenient for pressing and deforming. The Young's modulus of the pressure-sensitive adhesive increases after deformation and at room temperature after cooling, ensuring that it does not rebound after bending.

[0011] In some feasible implementation manners, the display screen further includes a surface layer, a second connection layer, and an optical film layer that are stacked in sequence. The second connection layer fixedly connects the surface layer and the optical film layer. The display panel is fixed between the optical film layer and the back film. The material of the second connection layer includes a thermoplastic material. The glass transition temperature of the second connection layer is in the range of 60 degrees Celsius to 120 degrees Celsius. The Young's modulus of the thermoplastic material for preparing the second connection layer in the elastic state is less than or equal to 100 kPa, and the Young's modulus of the thermoplastic material for preparing the second connection layer in the glass state is greater than 200 kPa.

[0012] In the embodiments of the present application, a certain bending force and temperature are applied to the areas that need to be bent, such as the edges and corners of the display screen. Since the second connection layer made of a thermoplastic material is in the elastic state, it can follow the surface layer to bend. Moreover, considering that the back film is also made of a thermoplastic material and is in the elastic state at this temperature, and the polarizer layer and the display panel itself do not have high hardness, the second connection layer, the polarizer layer, the display panel, and the back film can all be bent well under the extrusion of the surface layer, and the layers are closely attached to each other. After bending to the set degree, the temperature is lowered, and the second connection layer formed by the thermoplastic resin gradually cures and fixedly connects the surface layer and the polarizer layer, and the back film also cures to support the back side of the display panel. During the entire bending process, the display panel will not be subjected to too much squeezing force on both sides, reducing the degree of wrinkles, and even completely eliminating the wrinkles, improving the display effect of the display panel.

[0013] In some feasible implementation manners, the 180-degree peel force of the second connection layer is greater than or equal to 1200 g / inch, and / or the vertical pull-out strength of the second connection layer is greater than or equal to 0.05 MPa. A larger 180-degree peel force can prevent the display screen from separating during the thermoforming process, ensuring that the layers inside the display screen are closely attached. A larger vertical pull-out strength can prevent the layers inside the display screen from moving along the extension direction of the connection interface under the lateral impact force in scenarios such as when the display screen drops, preventing the layers inside the display screen from being misaligned when the display screen drops during use and improving the anti-collision strength of the display screen.

[0014] In some feasible implementation manners, the thermoplastic material includes at least one of silicone resin, silicone rubber, polyvinyl butyral, and acrylate. The materials in the embodiments of the present application have good light transmittance, improving the transmittance of light passing through the second connection layer of the display panel, and the glass transition temperature can be reduced by changing the molecular weight, so that the glass transition temperature of the second connection layer prepared from the materials in the embodiments of the present application is in the range of 60 degrees Celsius to 120 degrees Celsius, and has a relatively small Young's modulus during the thermoforming process of the display screen, which is beneficial to the thermoforming of the display screen.

[0015] In some feasible implementation manners, the second connection layer includes at least two connection layers arranged in a stacked manner, the at least two connection layers include a third connection layer, and the material of the third connection layer is the thermoplastic material. The second connection layer can have multiple layers and form a multi-layer stacked structure. While the Young's modulus of the second connection layer decreases during the thermo-bending process of the display screen, shear slip can also occur between the multiple second connection layers, which is beneficial to reducing the force on the display panel. The material of any one of the at least two connection layers can be the thermoplastic material. The multiple second connection layers are all supported by the thermoplastic material, which is convenient for increasing the shear slip of the thermoplastic material layers during thermo-bending forming, and is beneficial to reducing the force on the display panel.

[0016] In some feasible implementation manners, the at least two connection layers include a fourth connection layer, and the materials of the third connection layer and the fourth connection layer are different thermoplastic materials. The second connection layer can be a composite layer composed of multiple different types of thermoplastic materials. For example, the second connection layer can be a composite layer formed by stacking three second connection layers made of silicone resin, acrylate, and polyvinyl butyral.

[0017] In a second aspect, the present application provides a display screen, including a surface layer, a second connection layer, and an optical film layer that are sequentially stacked. The second connection layer fixedly connects the surface layer and the optical film layer. The material of the second connection layer includes a thermoplastic material. The glass transition temperature of the second connection layer is in the range of 60 degrees Celsius to 120 degrees Celsius. The Young's modulus of the thermoplastic material for preparing the second connection layer in the elastic state is less than or equal to 100 kPa, and the Young's modulus of the thermoplastic material for preparing the second connection layer in the glass state is greater than 200 kPa.

[0018] When preparing the display screen, the thermoplastic resin heated to the elastic state can be first applied between the flat surface layer and the polarizer, and a certain clamping force is applied to the surface layer and the polarizer. A certain bending force is applied to the areas that need to be bent, such as the edges and corners of the display screen. Since the thermoplastic resin is in the elastic state, it can follow the surface layer to bend. And since the back film is also made of thermoplastic material and is in the elastic state at this temperature, and the polarizer and the display panel itself do not have high hardness, the second connection layer, the polarizer, the display panel, and the back film can all be bent well under the extrusion of the surface layer, and the layers are closely attached to each other. After bending to the set degree, the temperature is lowered, and the second connection layer formed by the thermoplastic resin gradually solidifies and fixedly connects the surface layer and the polarizer, and the back film also solidifies to support the back side of the display panel. During the entire bending process, the display panel will not be subjected to too much squeezing force on both sides, reducing the degree of wrinkles, and even completely eliminating the wrinkles, improving the display effect of the display panel.

[0019] In some feasible implementation manners, the 180-degree peel force of the second connection layer is greater than or equal to 1200 grams-force per inch, and / or the vertical pull-out strength of the second connection layer is greater than or equal to 0.05 MPa. The larger 180-degree peel force can prevent the display screen from separating during the thermoforming process, ensuring that the layers inside the display screen are closely attached. The larger vertical pull-out strength can prevent the layers inside the display screen from experiencing lateral impact forces and causing creep along the extension direction of the connection interface in scenarios such as dropping the display screen, preventing the layers inside the display screen from being misaligned when the display screen is dropped during use, and improving the anti-collision strength of the display screen.

[0020] In some feasible implementation manners, the manufacturing material of the second connection layer includes at least one of silicone resin, silicone rubber, polyvinyl butyral, and acrylate. The materials described in the embodiments of the present application have good light transmittance, improving the light transmittance rate of the light passing through the second connection layer of the display panel, and can reduce its glass transition temperature by changing the molecular weight, so that the glass transition temperature of the second connection layer prepared from the materials described in the embodiments of the present application is in the range of 60 degrees Celsius to 120 degrees Celsius, having a relatively small Young's modulus during the thermoforming process of the display screen, which is beneficial to the thermoforming of the display screen.

[0021] In some feasible implementation manners, the second connection layer includes at least two connection layers stacked, and the at least two connection layers include a third connection layer, and the material of the third connection layer is the thermoplastic material. The second connection layer can have multiple layers and form a multi-layer stacked structure. While reducing the Young's modulus of the second connection layer during the thermoforming process of the display screen, shear slip can also occur between the multiple second connection layers, which is beneficial to reducing the force on the display panel. The material of any one of the at least two connection layers can be the thermoplastic material. The multiple second connection layers are all supported by the thermoplastic material, facilitating the increase of shear slip between the thermoplastic material layers during thermoforming, which is beneficial to reducing the force on the display panel.

[0022] In some feasible implementation manners, the at least two connection layers include a fourth connection layer, and the materials of the third connection layer and the fourth connection layer are different thermoplastic materials. The second connection layer can be a composite layer composed of multiple different types of thermoplastic materials. For example, the second connection layer can be a composite layer formed by stacking three second connection layers made of silicone resin, acrylate, and polyvinyl butyral.

[0023] In a third aspect, the present application provides a display module, including the display screen described in any one of the above and a support member, and the support member is located inside the display screen to support the display screen. The beneficial effects of the display module are similar to those of any one of the above display screens, and will not be elaborated here.

[0024] Fourthly, the present application provides an electronic device, which includes the display module described in any one of the above, and further includes a housing, and the housing is fixedly connected to the peripheral edge of the display module. Description of the Drawings

[0025] Figure 1 is a schematic diagram of the electronic device provided by the embodiment of the present application;

[0026] Figure 2 is a front view of the electronic device provided by the embodiment of the present application;

[0027] Figure 3 is a schematic diagram of a 2.5D and 3D curved display screen provided by the embodiment of the present application;

[0028] Figure 4 is an exploded schematic diagram of the surface layer, the screen stack and the housing provided by the embodiment of the present application;

[0029] Figure 5 is an assembly schematic diagram of the surface layer, the screen stack and the housing provided by the embodiment of the present application;

[0030] Figure 6 is a schematic diagram of a stack of the display module provided by the embodiment of the present application;

[0031] Figure 7 is another schematic diagram of a stack of the display module provided by the embodiment of the present application;

[0032] Figure 8 is a schematic diagram of a double-layer structure of a support structure provided by the embodiment of the present application;

[0033] Figure 9 is another schematic diagram of a double-layer structure of a support structure provided by the embodiment of the present application;

[0034] Figure 10 is a schematic diagram of the back film structure in a double-curved display screen provided by the embodiment of the present application;

[0035] Figure 11 is a schematic diagram of the back film structure in a four-curved display screen provided by the embodiment of the present application;

[0036] Figure 12 is a schematic diagram of a structure of a double-layer back film provided by the embodiment of the present application;

[0037] Figure 13 is another schematic diagram of a structure of a double-layer back film provided by the embodiment of the present application;

[0038] Figure 14 is another schematic diagram of a structure of a double-layer back film provided by the embodiment of the present application;

[0039] Figure 15It is a schematic diagram of the lamination of the back film and the second connection layer made of thermoplastic materials provided by the embodiment of the present application;

[0040] Figure 16 It is a schematic diagram of a structure of a double-layer second connection layer provided by the embodiment of the present application;

[0041] Figure 17 It is a schematic diagram of another structure of a double-layer second connection layer provided by the embodiment of the present application;

[0042] Figure 18 It is a schematic diagram of another structure of a double-layer second connection layer provided by the embodiment of the present application;

[0043] Figure 19 It is a schematic diagram of the lamination of the second connection layer made of thermoplastic materials provided by the embodiment of the present application;

[0044] Figure 20 It is a schematic diagram of a structure of a double-layer second connection layer provided by the embodiment of the present application;

[0045] Figure 21 It is a schematic diagram of another structure of a double-layer second connection layer provided by the embodiment of the present application;

[0046] Figure 22 It is a schematic diagram of another structure of a double-layer second connection layer provided by the embodiment of the present application. Detailed implementation manners

[0047] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0048] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of the present application will be explained and described below.

[0049] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0050] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0051] It should be understood that the term "and / or" used herein is merely a description of the same field of related objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " herein generally represents an "or" relationship between the related objects before and after.

[0052] Depending on the context, as used herein, the word "if" can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detected (stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)".

[0053] It should be understood that the "first", "second", etc. used in this application are only for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0054] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or a contact connection or an integral connection; for those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] For the "within... range" used in this application, unless it is separately stated that the end values are not included, it is default to include the two end values of the range. For example, within the range of 1 to 5, the two values of 1 and 5 are included.

[0056] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or a contact connection or an integral connection; for those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] In recent years, the display panel preparation technology of electronic devices has developed rapidly, and among them, flexible screens that can be bent are widely used as curved screens in electronic devices. Currently, four-curved display screens with better full-screen display effects are widely used. The four sides and four corner positions of the four-curved display screen have bending arcs. During the manufacturing process, especially at the connection between two adjacent curved surfaces, that is, at the four corner positions, stress that cannot be released is easily generated due to extrusion between the materials, resulting in wrinkles and affecting the display effect of the display screen.

[0058] This application provides an electronic device 100, which may include, but is not limited to, products with display interfaces such as mobile phones, tablet computers, laptop computers, ultra-mobile personal computers, handheld computers, walkie-talkies, Internet TVs, wearable devices, vehicle-mounted devices, dash cams, and security devices. The embodiments of this application do not impose special restrictions on the form of the above-mentioned electronic devices.

[0059] Exemplarily, please refer to Figure 1 , in the embodiments of this application, the electronic device 100 is described by taking a curved-screen mobile phone as an example. Figure 1 FIG. is a three-dimensional schematic diagram of the electronic device 100 provided by the embodiments of this application. Figure 2 FIG. is a formal schematic diagram of the electronic device 100 provided by the embodiments of this application. The electronic device 100 includes a display module 10 and a housing 20. The display module 10 is connected to the housing 20. Specifically, it can be fixedly connected to the outer periphery of the housing and the display module. The housing 20 may include a middle frame and a rear cover. The middle frame and the rear cover may be a split structure or an integrated structure. The embodiments of this application do not make specific limitations.

[0060] The display module 10 is installed on the housing 20. Among them, the housing 20 has a receiving cavity, and components such as the circuit board, electronic components, camera module, processor, and battery of the electronic device 100 can all be installed in the receiving cavity of the housing 20. The display module 10 covers the opening of the receiving cavity of the housing 20. The display module 10 and the housing 20 are hermetically connected to form a sealed receiving cavity to protect the components in the receiving cavity from water, dust, etc. The housing 20 can be made of materials such as metal (such as aluminum alloy, titanium alloy, and stainless steel), plastic (such as acrylonitrile-butadiene-styrene, polycarbonate, and polypropylene), or glass (such as anti-glare glass). The housing 20 made of materials such as metal, plastic, or glass can meet the requirements of wear resistance, impact resistance, corrosion resistance, and aesthetics of the appearance of the electronic device 100.

[0061] In some possible implementation manners, the display module 10 may be a four-curved screen, such as Figure 1 and Figure 2As shown, the side edges of the display module 10 in four directions, namely the X direction, the opposite direction of X, the Z direction, and the opposite direction of Z, are all bent towards the side of the opposite direction of Y to form a four-curved surface screen. The four corners of the display module 10 are also bent towards the side of the opposite direction of Y to form a curved surface display module 10 with all outer edges bent. In one embodiment, the display module 10 can also be a double-curved surface screen (not shown in the figure). The double-curved surface screen can refer to Figure 2 , only the side edges of the display module 10 in the X direction and the opposite direction of X are bent towards the side of the opposite direction of Y, and the side edges in the Z direction and the opposite direction of Z are not bent.

[0062] Among them, the curved surface screen can be a 2.5D curved surface screen or a 3D curved surface screen. Refer to Figure 3 As shown, in the 2.5D curved surface screen, the edges on both sides of the display screen in the X direction and the opposite direction of X are only curved on one side in the Y direction and are flat on the side of the opposite direction of Y. In the 2.5D screen, only the outer surface edges of the surface layer (which can be a glass cover plate) can be made into a curved surface, while the inner side of the surface layer is flat. In this structure, each layer such as the polarizing layer, the display panel, and the back film can be a flat structure. Refer to Figure 3 As shown, in the 3D curved surface screen, the edges on both sides of the display screen in the X direction and the opposite direction of X in this application are bent towards the side of the opposite direction of Y. The outer surface on one side in the Y direction is in a protruding curved shape, and the inner surface on the side of the opposite direction of Y is in a concave curved shape. For the 3D curved surface screen, the embodiment of this application takes the four-curved surface screen as an example. When the side is bent, especially in the bending area at the corner position of the four-curved surface screen, the side bending will cause the display panel in the display screen to be subjected to a squeezing force in the transverse direction (perpendicular or inclined to the thickness direction, which can be the extending direction on the extending surface of the display panel), resulting in wrinkles. The wrinkles will cause the thickness of the display panel in the thickness direction to be uneven, resulting in unclear display imaging in the corner area of the display screen. The wrinkle phenomenon is particularly obvious in the corner area.

[0063] This application provides a display module 10, which can be applied to the electronic device in the above-mentioned embodiment. The four sides of the display module 10 are bent to form a four-curved surface screen. Refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown. The display module 10 includes a display screen 11 and a support structure 12. Both the display screen 11 and the support structure 12 are in a plate shape, and the display screen 11 and the support structure 12 are stacked.

[0064] The display screen 11 at least includes a surface layer 111, a second connection layer 112, a polarizing layer 113, a display panel 114, and a back film 115. The surface layer 111, the second connection layer 112, the polarizing layer 113, the display panel 114, and the back film 115 are stacked in sequence. Refer to Figure 4 and Figure 5As shown, the surface layer 111 is located on the outermost surface and can be a glass cover plate, which can be a transparent glass cover plate so that the display panel 114 can display through the glass cover plate. Laminated structures such as the second connection layer, polarizing layer, display panel, and back film form the screen stack 11a. The screen stack 11a is located inside the surface layer 111. The surface layer 111 can protect the screen stack 11a from water, dust, and other debris, and prevent the screen stack 11a from being damaged by extrusion. The side edges of the surface layer 111 can be connected to the housing 20. For example, the screen stack 11a is located in the cavity formed by the surface layer 111 and the housing 20.

[0065] The second connection layer 112 can be an optically clear adhesive (OCA) layer, which can connect the surface layer 111 and the polarizing layer 113 to form an integral structure and facilitate the light emitted by the display panel 114 to pass through for display. The polarizing layer 113 can be a polarizer (POL), which can eliminate the reflection of the metal traces on the display panel 114 to improve the visibility of the display screen. The display panel 114 can be a display touch layer (PANEL). For example, a display layer and a touch layer are sequentially formed on a substrate to form a display panel with touch and display functions. At the same time, the display touch layer can also obtain the actions of the user on the display screen, realize the acquisition of user actions, and convert them into electrical signals for processing to achieve the interaction between the electronic device and the user. The back film 115 can be a back film provided on one side of the display panel 114. The display touch layer is mostly a flexible layer, and the display panel 114 is attached to the back film 115, and the back film 115 provides support for the display panel 114.

[0066] In one embodiment, the surface layer 111 can be located on the display surface side of the display screen 11. In this way, when the display module 10 is installed on the electronic device 100, the surface layer 111 can protect the other layer structures of the display screen 11 and allow the light emitted by the display panel 114 to pass through. The surface layer 111 can be the cover plate on the surface of the display screen. The materials of the surface layer 111 include but are not limited to glass and transparent polyimide. The present application does not specifically limit the materials of the surface layer 111.

[0067] With the rapid development of the display panel preparation technology of electronic devices, flexible screens that can be bent are widely used as curved screens in electronic devices. Currently, the flexible screen support structure is mainly the support structure 12 disposed below the display screen 11. In one embodiment, the support structure 12 includes a fifth connection layer 121 and a support member 122. The fifth connection layer 121 can be an adhesive layer for fixedly connecting the support member 122 and the display screen 11. Among them, the support member 122 is usually a copper foil to enhance the support and bending properties of the screen. The support structure 12 has a certain structural strength to meet the support strength requirements for the display screen 11. However, for a curved screen, when preparing the curved part, usually the flat display screen 11 and the support structure 12 are laminated and fixed first, and then the surface layer 111 of the display screen 11 is bent to form a curved screen structure. During the bending process of the surface layer 111, the surface layer 111 presses down on the polarizer layer 113 and the display panel 114, and the support structure 12 provides support on the other side of the polarizer layer 113 and the display panel 114. Under the mutual extrusion of the surface layer 111 and the support structure 12, the polarizer layer 113 and the display panel 114 are prone to damage, especially the display panel 114 is prone to damage, resulting in structural dead pixels in the display module 10 and affecting the display effect of the display module 10. Moreover, at the corner positions of the display module 10, the flat display module 10 is bent to form an arc-shaped curved corner in the corner area. During the bending process, the surface layer 111 and the back film 115 above and below the display panel 114 will press the display panel 114 along the direction of the extension plane, resulting in multiple wrinkles on the display panel 114 and reducing the display effect of the display panel 114.

[0068] In the embodiment of the present application, the display screen of the display module 10 is improved, which will be described below with reference to the accompanying drawings.

[0069] The present application provides a display screen 11, which includes a surface layer 111, a second connection layer 112, a polarizer layer 113, a display panel 114, and a back film 115 that are laminated and connected. The material of the surface layer 111 can include but is not limited to glass and transparent polyimide. It can be prepared into a flat shape first, and then the sides and corners are bent by heating and softening to prepare a double-curved screen or a four-curved screen with bent sides and corners.

[0070] During the heating and bending process, the hardness of the surface layer 111 will be correspondingly reduced to facilitate bending more. This temperature can be in the range of 60 degrees Celsius to 80 degrees Celsius. For example, it can be about 70 degrees Celsius. At this temperature, each layer in the display screen 11 can be appropriately softened to facilitate bending more, and to avoid damage to the structure and performance caused by too high a temperature. At this temperature, the back film 115 still has a relatively high hardness and relatively poor bendability. After hot bending, obvious wrinkles will appear in the corner area of the display panel 114. If a material with a lower hardness is selected for the back film 115, the back film 115 will not exert a strong extrusion on the display panel 114 during hot bending, and the wrinkling situation in the corner area of the display panel 114 after hot bending will be improved. However, after the hot bending is completed and cooled, the strength of the back film 115 is correspondingly lower and cannot meet the requirement for the support strength of the display panel 114.

[0071] In the embodiment of the present application, the material of the back film 115 includes a thermoplastic material. A thermoplastic material refers to a material that can be plastic at a certain temperature when heated and will solidify to increase hardness after the temperature decreases. When the thermoplastic material is heated to a certain temperature, its corresponding hardness will be reduced to be plastic, and it will return to a solid state to maintain a relatively high hardness after the temperature decreases. Moreover, the thermoplastic material is in an elastic state with plasticity at high temperature and in a glass state with relatively high hardness at low temperature, and the elastic state and the glass state can be switched with the change of temperature.

[0072] In the embodiment of the present application, the material of the back film 115 can include a thermoplastic material. Among them, the glass transition temperature (Tg) of the back film 115 can be in the range of 60 degrees Celsius to 120 degrees Celsius. The Young's modulus of the thermoplastic material for preparing the back film 115 in the elastic state is less than or equal to 800 MPa, and the Young's modulus of the thermoplastic material for preparing the back film 115 in the glass state is greater than 1000 MPa.

[0073] In the embodiment of the present application, by defining the material of the back film 115 as a thermoplastic material, during the side hot bending process of the display screen 11, the Young's modulus of the material for preparing the back film 115 can be reduced, so that the display screen 11 can be bent better, and it will not cause the surface layer 111 and the back film 115 to strongly extrude the display panel 114, preventing the display screen 11 from being damaged during the hot bending process.

[0074] Refer to Figure 10 As shown, for a hyperbolic display screen, the shape of the back film 115 is as Figure 10As shown, the back film 115 includes a middle planar region 115a and a curved region 115b located on the side of the planar region 115a. The back film 115 is made of a thermoplastic material. The back film 115 can be first prepared in a flat plate shape, then heated to the thermoforming temperature, and bent by applying force at the edge to form the planar region 115a and the curved region 115b. During the process of heating to the thermoforming temperature, the material of the back film 115 changes from the glassy state to the elastic state, and the Young's modulus decreases, which is beneficial to the bending and forming of the curved region 115b.

[0075] Refer to Figure 11 As shown, for the display screen of the four-curved surface screen, the shape of the back film 115 is as Figure 11 As shown, the back film 115 includes a middle planar region 115a and a curved region 115b located on the side of the planar region 115a. The curved region 115b undergoes a large bending deformation in the four corner regions. The back film 115 is made of a thermoplastic material. The back film 115 can be first prepared in a flat plate shape, then heated to the thermoforming temperature, and bent by applying force at the edge to form the planar region 115a and the curved region 115b. During the process of heating to the thermoforming temperature, the material of the back film 115 changes from the glassy state to the elastic state, and the Young's modulus decreases, which is beneficial to the bending and forming of the curved region 115b.

[0076] In a feasible implementation manner, the thermoplastic material used for the back film 115 can be at least one of polycarbonate (PC), polyvinyl butyral (TPU), polypropylene (PP), polyethylene (PE), and polymethyl methacrylate (PMMA).

[0077] The above materials can reduce their glass transition temperature by changing the molecular weight, so that the glass transition temperature Tg of the above materials is in the range of 60 °C to 120 °C, and has a relatively small Young's modulus during the thermoforming process of the display screen, which is beneficial to the thermoforming of the display screen.

[0078] In the embodiments of the present application, the material of the back film 115 is designed to include a thermoplastic material, and the glass transition temperature Tg of the thermoplastic material is in the range of 60 °C to 120 °C. Specifically, it can be selected according to the thermoforming temperature of the surface layer 111, so that the glass transition temperature Tg of the back film 115 is less than the thermoforming temperature of the surface layer 111. When the display module 10 is prepared into a curved screen, both the surface layer 111 and the back film 115 are softened to a certain extent by heating. In one embodiment, the Young's modulus of the thermoplastic material for preparing the back film 115 in the elastic state (when the temperature of the back film 115 is greater than its glass transition temperature Tg, the back film 115 softens and becomes elastic) is less than or equal to 800 MPa. At this strength, when the back film 115 is bent, it will not cause a relatively strong extrusion to the display panel 114. The surface layer 111 bends and squeezes the display panel 114 and the back film 115, and the clamping force of the surface layer 111 and the back film 115 on the display panel 114 is small, reducing or even preventing the display panel 114 from wrinkling.

[0079] And the glass transition temperature Tg of the back film 115 is greater than or equal to 60 °C, so that the glass transition temperature of the back film 115 is greater than the ambient temperature when the display module 10 is in use. During the use process of the display module 10 after bending and forming, both the surface layer 111 and the back film 115 have a certain hardness to protect the display panel 114 clamped in the middle. In one embodiment, the Young's modulus of the thermoplastic material for preparing the back film 115 in the glass state (when the temperature of the back film 115 is less than its glass transition temperature Tg, the back film 115 hardens and becomes glassy) is greater than 1000 MPa. At this hardness, the back film 115 can better support the display panel 114 when the display module 10 is in use, preventing the display panel 114 from deforming or even being damaged due to force.

[0080] In one embodiment, the glass transition temperature Tg of thermoplastic materials such as polycarbonate is related to the size of its own molecular weight. In order to prepare a thermoplastic material with a glass transition temperature Tg in the range of 60 °C to 120 °C, it is necessary to reduce the molecular weight of the material. The present application can obtain a thermoplastic material with a glass transition temperature Tg in the range of 60 °C to 120 °C by reducing the molecular weight of the thermoplastic material. Considering the mechanical property strength of the thermoplastic material, preventing the material from becoming brittle, and ensuring that the material has a certain creep (force application and rebound) performance to prevent the reduction of the mechanical properties of the thermoplastic material from causing greater damage to the display panel. And when the thermoplastic material in the present application is applied to the back film 115, a lower modulus needs to be designed. On the one hand, it can reduce the large extrusion of the back film 115 on the display panel during thermoforming, and on the other hand, the reduction of the Young's modulus can accelerate the thermoforming speed of the display screen and improve the production efficiency of the display screen.

[0081] In some possible embodiments, refer to Figure 12 As shown, the number of the back films 115 can be at least two layers, at least two layers of the back films 115 are stacked, and the material of at least one of the at least two layers of the back films 115 is the thermoplastic material. The back film includes at least two layers of back films arranged in a stacked manner, so as to Figure 12 Taking the double-layer back film 115 structure shown in

[0082] In one embodiment, refer to Figure 13 As shown, the number of the back films 115 can be at least two layers, at least two layers of the back films 115 are stacked, and the material of any one of the at least two layers of back films is the thermoplastic material. Taking Figure 12 the double-layer back film 115 structure shown in

[0083] In one embodiment, refer to Figure 14 As shown, when the number of the back films 115 is at least two layers, and the materials of two or more of the at least two layers of back films 115 are thermoplastic materials. For example, Figure 14 in

[0084] In some possible embodiments, the material of the back film 115 can be plastic or the like. For example, it is made of polyethylene terephthalate (PET) material. The glass transition temperature Tg of the PET material is greater than or equal to 150 degrees Celsius. When the hot bending temperature is above 150 degrees Celsius, a back film 115 made of plastic or the like can be used. Moreover, the production cost is low, the optical performance is good, the transmittance is high, which is beneficial to the recognition of optical fingerprints.

[0085] In some possible embodiments, referring to Figure 7 As shown, the display screen described in the embodiment of the present application further includes a first connection layer 116. The first connection layer 116 is located between the display panel 114 and the back film 115 to fixedly connect the display panel 114 and the back film 115. The material of the first connection layer includes a pressure-sensitive material, specifically, it can be a pressure-sensitive adhesive tape (PSA). A pressure-sensitive adhesive tape is a tape with an adhesive applied on a strip-shaped substrate. The adhesive can be a pressure-sensitive adhesive, which has the characteristic of being sensitive to pressure. The pressure-sensitive adhesive tape can be pasted between the display panel 114 and the back film 115, and a certain pressure is applied to the display panel 114 and the back film 115 through a clamping mechanism, so that the pressure-sensitive adhesive tape tightly bonds the display panel 114 and the back film 115. Moreover, by applying pressure for a short time, the pressure-sensitive adhesive tape can have a good bonding effect and has a certain heat resistance. Among them, the Young's modulus of the pressure-sensitive adhesive material is about 25 kPa at the hot bending temperature, and the Young's modulus at room temperature after cooling is about 160 kPa. Under the high-temperature conditions during hot bending forming, the Young's modulus is small to reduce the fitting stress between the first connection layer and the display panel 114 and the back film 115 respectively, facilitating the pressing deformation. The Young's modulus of the pressure-sensitive adhesive increases after deformation and at room temperature after cooling, ensuring that it does not rebound after bending.

[0086] When preparing the display module 10, the surface layer 111, the second connection layer 112, the polarizing layer 113, the display panel 114 and the back film 115 which are flat and laminated can be prepared first. The display panel 114 and the back film 115 are fixedly connected as a whole through the first connection layer 116 composed of a pressure-sensitive adhesive tape. The edge and corner areas of the display module 10 that need to be bent are heated to a certain temperature by a heating device, for example, heated to 100 degrees Celsius. At this temperature, the surface layer 111 and the back film 115 are softened to facilitate bending, while the first connection layer 116 has heat resistance and can maintain good adhesiveness in the temperature range of 0 degrees Celsius to 200 degrees Celsius, so as to better bond the display panel 114 and the back film 115, prevent the display panel 114 and the back film 115 from separating during bending, and ensure that the display panel 114 and the back film 115 are always in fit.

[0087] In some possible embodiments, referring to Figure 15As shown in the figure, this embodiment provides a display screen 11, which includes a surface layer 111, a second connection layer 112, a polarizing layer 113, a display panel 114, and a back film 115 that are stacked and connected. Among them, the second connection layer 112 can be an optically clear adhesive layer (OCA), which can connect the surface layer 111 and the polarizing layer 113 to form an integral structure.

[0088] The material of the second connection layer 112 includes a thermoplastic material, which refers to a material that can be plasticized when heated to a certain temperature and will solidify to increase hardness after the temperature decreases. The thermoplastic material will have a corresponding decrease in hardness to become plastic when heated to a certain temperature and will return to a solid state to maintain a high hardness after the temperature decreases. Moreover, the thermoplastic material is in an elastic state with plasticity at high temperatures and in a glass state with high hardness at low temperatures, and the elastic state and the glass state can be switched following the change of temperature.

[0089] In the embodiment of the present application, the material of the second connection layer 112 may include a thermoplastic material, specifically a thermoplastic resin. The glass transition temperature Tg of the second connection layer 112 may be in the range of 60 degrees Celsius to 120 degrees Celsius. The Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the elastic state is less than or equal to 100 MPa, and the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the glass state is greater than 200 MPa.

[0090] In one embodiment, when preparing the display screen 11, the thermoplastic resin heated to the elastic state can be first applied between the flat surface layer 111 and the polarizing layer 113, and a certain clamping force is applied to the surface layer 111 and the polarizing layer 113. A certain bending force is applied to the areas that need to be bent, such as the edges and corners of the display screen 11. Since the thermoplastic resin is in the elastic state, it can bend following the surface layer 111. Also, considering that the back film 115 is also a thermoplastic material and is in the elastic state at this temperature, and the polarizing layer 113 and the display panel 114 themselves do not have high hardness, the second connection layer 112, the polarizing layer 113, the display panel 114, and the back film 115 can all be bent well under the extrusion of the surface layer 111, and the layers are closely attached to each other. After bending to the set degree, the temperature is lowered, and the second connection layer 112 formed by the thermoplastic resin gradually solidifies and fixedly connects the surface layer 111 and the polarizing layer 113, and the back film 115 also solidifies to support the back side of the display panel 114. During the entire bending process, the display panel 114 will not be subjected to too much squeezing force on both sides, thereby reducing the degree of wrinkles, and even completely eliminating the wrinkles, improving the display effect of the display panel 114.

[0091] In one embodiment, the thermoplastic material used for the second connection layer 112 may be at least one of silicone resin, silicone rubber, polyvinyl butyral (TPU), and acrylic ester.

[0092] The materials described in the embodiments of the present application have good light transmittance, which can improve the light transmission rate of the display panel through the second connection layer. Moreover, by changing the molecular weight, the glass transition temperature can be reduced so that the glass transition temperature Tg of the second connection layer prepared from the materials described in the embodiments of the present application is in the range of 60 °C to 120 °C. During the thermoforming process of the display screen, it has a relatively small Young's modulus, which is beneficial to the thermoforming of the display screen.

[0093] In the embodiments of the present application, by designing the material of the second connection layer 112 to include a thermoplastic material, and the glass transition temperature Tg of the thermoplastic material is in the range of 60 °C to 120 °C, which can be specifically selected according to the thermoforming temperature of the surface layer 111, so that the glass transition temperature Tg of the second connection layer 112 is less than the thermoforming temperature of the surface layer 111. When the display module 10 is prepared into a curved screen, the surface layer 111 and the second connection layer 112 are softened to a certain extent by heating. In one embodiment, the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the elastic state (when the temperature of the second connection layer 112 is higher than its glass transition temperature Tg, the second connection layer 112 softens and becomes elastic) is less than or equal to 100 MPa. At this strength, when the second connection layer 112 bends, it will not cause a strong extrusion to the display panel 114. Considering that the back film 115 is also a thermoplastic material and is in the elastic state at this temperature, and the polarizer 113 and the display panel 114 itself do not have high hardness, the second connection layer 112, the polarizer 113, the display panel 114, and the back film 115 can all be bent well under the extrusion of the surface layer 111. The surface layer 111 bends and extrudes the second connection layer 112, the display panel 114, and the back film 115, and the layers are closely attached to each other. The clamping force of the surface layer 111 and the back film 115 on the display panel 114 is small, reducing or even preventing the display panel 114 from wrinkling.

[0094] Moreover, the glass transition temperature Tg of the second connection layer 112 is greater than or equal to 60 °C, such that the glass transition temperature of the second connection layer 112 is greater than the ambient temperature during the use of the display module 10. During the use of the display module 10 after bending and forming, both the surface layer 111 and the second connection layer 112 have a certain hardness to protect the adhered display panel 114. In one embodiment, the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the glass state (when the temperature of the second connection layer 112 is less than its glass transition temperature Tg, the second connection layer 112 hardens into the glass state) is greater than 200 MPa. At this hardness, the second connection layer 112 can better protect the display panel 114 during the use of the display module 10, and the pressure transmitted from the surface layer 111 (when pressing the screen during personnel operation) can be accurately and quickly transmitted into the display panel 114, ensuring the sensitivity of the touch function of the display module 10.

[0095] In one embodiment, for example, the glass transition temperature Tg of a thermoplastic material such as silicone resin is related to the size of its own molecular weight. In order to prepare a thermoplastic material with a glass transition temperature Tg in the range of 60 °C to 120 °C, it is necessary to reduce the molecular weight of the material. In this application, a thermoplastic material with a glass transition temperature Tg in the range of 60 °C to 120 °C can be obtained by reducing the molecular weight of the thermoplastic material. Considering the mechanical property strength of the thermoplastic material, preventing the material from becoming brittle, and ensuring that the material has a certain creep (force application and rebound) property to prevent a large damage to the display panel caused by the reduction of the mechanical properties of the thermoplastic material. Moreover, when the thermoplastic material is applied to the second connection layer 112 in this application, a lower modulus needs to be designed. On the one hand, it can reduce the large extrusion of the second connection layer 112 on the display panel during thermoforming, and on the other hand, the reduction of the Young's modulus can accelerate the thermoforming speed of the display screen and improve the manufacturing efficiency of the display screen.

[0096] In one possible implementation, the 180° peel force of the second connection layer 112 is greater than or equal to 1200 g / inch, and the peel force of the second connection layer 112 can be measured by a 180° peel force tester. As the connection layer between the surface layer 111 and the polarizer layer 113, through testing, it can be measured that the 180° peel force of the second connection layer 112 is greater than or equal to 1200 g / inch, so that the second connection layer 112 can better connect the surface layer 111 and the polarizer layer 113, and will not peel off during the process of bending preparation, forming and subsequent use, improving the connection strength and integrity of the display module 10.

[0097] In one embodiment, the vertical pulling strength of the second connection layer 112 is greater than or equal to 0.05 MPa. Herein, the vertical pulling strength refers to the stress required when both sides of the laminate are bonded with a steel plate of 40*40 area and a strong adhesive, and then a pulling force is applied in the direction perpendicular to the bonding surface until the connection interface is damaged. Specifically, the force of vertical pulling is perpendicular to the connection interface to correspond to the scenario of the entire screen bending deformation. The force of 180-degree peel strength is parallel to the connection interface, corresponding to the scenario where the adjacent two layers inside the screen move along the direction extending along the connection interface when the entire screen drops. A larger 180-degree peel strength can prevent the display screen from separating during the thermoforming process to ensure that the layers inside the display screen are closely attached. A larger vertical pulling strength can prevent the layers inside the display screen from moving along the direction extending along the connection interface due to the lateral impact force in scenarios such as when the display screen drops, and prevent the layers inside the display screen from being misaligned when the display screen is dropped during use, thereby improving the anti-collision strength of the display screen.

[0098] In some possible implementation manners, referring to Figure 16 as shown, the number of the second connection layers 112 can be at least two layers, at least two of the second connection layers 112 are stacked, and the material of at least one of the at least two second connection layers 112 is the thermoplastic material. The second connection layer can include at least two connection layers arranged in a stacked manner to Figure 16 taking the double-layer second connection layer 112 structure shown in

[0099] In one embodiment, referring to Figure 17 as shown, the number of the second connection layers 112 can be at least two layers, at least two of the second connection layers 112 are stacked, and the material of any one of the at least two second connection layers 112 is the thermoplastic material. Taking Figure 17 the double-layer second connection layer 112 structure shown in

[0100] In one embodiment, referring to Figure 18As shown, when the number of the second connection layers 112 is at least two layers, and among at least two layers of the second connection layers 112, two or more of the second connection layers 112 are made of thermoplastic materials. For example, Figure 18 in Figure 18 , the materials of the third connection layer 1121 and the fourth connection layer 1122 can both be thermoplastic materials, and the materials of the third connection layer 1121 and the second back film 1152 are different thermoplastic materials. In one embodiment, the material of the third connection layer 1121 can be silicone resin, and the material of the fourth connection layer 1122 can be acrylate. In one embodiment, when three layers of the second connection layers 112 are made of thermoplastic materials, the materials of the three second connection layers 112 can be silicone resin, acrylate, and polyvinyl butyral respectively.

[0101] In one embodiment, the number of the back films 115 is at least two layers, and the number of the second connection layers 112 is at least two layers. Among the multiple back films 115, the materials of some layers can be thermoplastic materials, or the materials of all layers can be thermoplastic materials, and the two or more thermoplastic material back films 115 can be made of different thermoplastic materials. Similarly, among the multiple second connection layers 112, the materials of some layers can be thermoplastic materials, or the materials of all layers can be thermoplastic materials, and the two or more thermoplastic material second connection layers 112 can be made of different thermoplastic materials. Under different application requirements, the above embodiments can be adaptively adjusted and combined.

[0102] The present application also provides a specific implementation manner of a display screen. Refer to Figure 19 As shown, this implementation manner provides a display screen 11, and the display screen 11 includes a surface layer 111, a second connection layer 112, a polarizing layer 113, a display panel 114, and a back film 115 that are stacked and connected. Among them, the second connection layer 112 can be a transparent optical adhesive layer (Optically Clear Adhesive, OCA), which can connect the surface layer 111 and the polarizing layer 113 to form an integral structure.

[0103] The material of the second connection layer 112 includes thermoplastic materials. Thermoplastic materials refer to a kind of material that can be plasticized when heated to a certain temperature and will solidify to increase hardness after the temperature decreases. The hardness of thermoplastic materials will decrease to be plasticizable after being heated to a certain temperature, and will return to a solid state to maintain a high hardness after the temperature decreases. Moreover, thermoplastic materials are in an elastic state with plasticity at high temperature and in a glass state with high hardness at low temperature, and the elastic state and the glass state can be switched following the change of temperature.

[0104] In the embodiments of the present application, the material of the second connection layer 112 may include a thermoplastic material, specifically a thermoplastic resin. The glass transition temperature Tg of the second connection layer 112 may be in the range of 60 °C to 120 °C. The Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the elastic state is less than or equal to 100 MPa, and the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the glassy state is greater than 200 MPa.

[0105] In one embodiment, when preparing the display screen 11, the thermoplastic resin heated to the elastic state may be first applied between the flat surface layer 111 and the polarizing layer 113, and a certain clamping force may be applied to the surface layer 111 and the polarizing layer 113. A certain bending force is applied to the areas that need to be bent, such as the edges and corners of the display screen 11. Since the thermoplastic resin is in the elastic state, it can bend along with the surface layer 111. And since the back film 115 is also made of a thermoplastic material and is in the elastic state at this temperature, and the polarizing layer 113 and the display panel 114 themselves do not have high hardness, the second connection layer 112, the polarizing layer 113, the display panel 114 and the back film 115 can all be bent well under the extrusion of the surface layer 111, and the layers are closely attached to each other. After bending to the set degree, the temperature is lowered, and the second connection layer 112 formed by the thermoplastic resin gradually solidifies and fixedly connects the surface layer 111 and the polarizing layer 113, and the back film 115 also solidifies to support the back side of the display panel 114. During the entire bending process, the display panel 114 will not be subjected to too much extrusion force on both sides, thus reducing the degree of wrinkles, and even completely eliminating the wrinkles, improving the display effect of the display panel 114.

[0106] In some possible implementation manners, the material of the back film 115 may be plastic, etc., for example, it is made of polyethylene terephthalate (PET) material. The glass transition temperature Tg of the PET material is greater than or equal to 150 °C. When the hot bending temperature is above 150 °C, the back film 115 made of materials such as plastic can be used, and it has low manufacturing cost, good optical properties, high transmittance, and is beneficial to the recognition of optical fingerprints.

[0107] In some possible embodiments, the material of the back film 115 may be a thermoplastic material, including at least one of polycarbonate, polyvinyl butyral, polypropylene, polyethylene, and polymethyl methacrylate. And the glass transition temperature of the thermoplastic material for preparing the back film 115 is in the range of 60 °C to 120 °C, the Young's modulus of the thermoplastic material for preparing the back film 115 in the elastic state is less than or equal to 800 MPa, and the Young's modulus of the thermoplastic material for preparing the back film 115 in the glassy state is greater than 1000 MPa. It can complete the transition from the glassy state to the elastic state during the thermo-bending process of the display screen. At the same time, due to the decrease in the Young's modulus of the back film during the transition process, plastic deformation can easily occur, reducing the stress on the display panel, so that the display screen can be bent better, avoiding wrinkles at the corners of the display panel and preventing damage to the display screen during the thermo-bending process.

[0108] In one embodiment, the thermoplastic material used for the second connection layer 112 may be at least one of silicone resin, silicone rubber, polyvinyl butyral (TPU), and acrylic ester.

[0109] The materials described in the embodiments of the present application have good light transmittance, which can improve the light transmittance of the display panel through the second connection layer. And the glass transition temperature can be reduced by changing the molecular weight, so that the glass transition temperature Tg of the second connection layer prepared from the materials described in the embodiments of the present application is in the range of 60 °C to 120 °C, and has a relatively small Young's modulus during the thermo-bending process of the display screen, which is beneficial to the thermo-bending forming of the display screen.

[0110] In an embodiment of the present application, the material of the second connection layer 112 is designed to include a thermoplastic material, and the glass transition temperature Tg of the thermoplastic material ranges from 60 °C to 120 °C. Specifically, it can be selected according to the thermoforming temperature of the surface layer 111, such that the glass transition temperature Tg of the second connection layer 112 is less than the thermoforming temperature of the surface layer 111. When the display module 10 is prepared into a curved screen, the surface layer 111 and the second connection layer 112 are softened to a certain extent by heating. In one embodiment, the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the elastic state (when the temperature of the second connection layer 112 is greater than its glass transition temperature Tg, the second connection layer 112 is softened and becomes the elastic state) is less than or equal to 100 MPa. At this strength, when the second connection layer 112 is bent, it will not cause a relatively strong extrusion to the display panel 114. The surface layer 111 bends and extrudes the second connection layer 112 and the display panel 114, and the layers are closely attached to each other. The extrusion force of the second connection layer 112 on the display panel 114 is small, reducing or even preventing the display panel 114 from wrinkling.

[0111] The glass transition temperature Tg of the second connection layer 112 is greater than or equal to 60 °C, such that the glass transition temperature of the second connection layer 112 is higher than the ambient temperature during the use of the display module 10. During the use of the display module 10 after bending and forming, both the surface layer 111 and the second connection layer 112 have a certain hardness to protect the attached display panel 114. In one embodiment, the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the glass state (when the temperature of the second connection layer 112 is less than its glass transition temperature Tg, the second connection layer 112 is hardened and becomes the glass state) is greater than 200 MPa. At this hardness, the second connection layer 112 can better protect the display panel 114 during the use of the display module 10. The pressure transmitted from the surface layer 111 (when pressing the screen during personnel operation) can be accurately and quickly transmitted to the display panel 114, ensuring the sensitivity of the touch function of the display module 10.

[0112] In a possible implementation manner, the 180-degree peel force of the second connection layer 112 is greater than or equal to 1200 g / inch. The peel force of the second connection layer 112 can be measured by a 180-degree peel force tester. As the connection layer between the surface layer 111 and the polarizer layer 113, through testing, it can be measured that the 180-degree peel force of the second connection layer 112 is greater than or equal to 1200 g / inch, so that the second connection layer 112 can better connect the surface layer 111 and the polarizer layer 113, and will not peel off during the process of bending preparation and post-forming use, improving the connection strength and integrity of the display module 10.

[0113] In one embodiment, the vertical pulling strength of the second connection layer 112 is greater than or equal to 0.05 MPa. Here, the vertical pulling strength refers to the stress required when the two sides of the laminate are bonded with a steel plate of 40*40 area and a strong adhesive, and then a pulling force is applied in the direction perpendicular to the bonding surface until the connection interface is damaged. Specifically, the force of the vertical pull is perpendicular to the connection interface to correspond to the scenario of the entire screen bending deformation. The force of the 180-degree peel is parallel to the connection interface, corresponding to the scenario where the internal adjacent layers of the entire screen move along the direction extending along the connection interface when the screen drops. A larger 180-degree peel force can prevent the display screen from separating during the thermoforming process to ensure that the layers inside the display screen are closely adhered. A larger vertical pulling strength can prevent the layers inside the display screen from moving along the direction extending along the connection interface due to the lateral impact force in scenarios such as when the display screen drops, prevent the layers inside the display screen from being misaligned when the display screen is dropped during use, and improve the anti-collision strength of the display screen.

[0114] In some possible implementation manners, referring to Figure 20 as shown, the number of the second connection layers 112 can be at least two layers. At least two layers of the second connection layers 112 are stacked, and the material of at least one of the at least two layers of the second connection layers 112 is the thermoplastic material. The second connection layer 112 includes at least two connection layers to Figure 20 taking the double-layer second connection layer 112 structure shown in

[0115] In one embodiment, referring to Figure 21 as shown, the number of the second connection layers 112 can be at least two layers. At least two layers of the second connection layers 112 are stacked, and the material of any one of the at least two layers of the second connection layers 112 is the thermoplastic material. Taking Figure 21 the double-layer second connection layer 112 structure shown in

[0116] In one embodiment, referring to Figure 22 as shown, when the number of the second connection layers 112 is at least two layers, and the material of two or more of the at least two layers of the second connection layers 112 is the thermoplastic material. For example,Figure 22 Among them, the materials of the third connection layer 1121 and the fourth connection layer 1122 can both be thermoplastic materials, and the materials of the third connection layer 1121 and the second back film 1152 are different thermoplastic materials. In one embodiment, the material of the third connection layer 1121 can be silicone resin, and the material of the fourth connection layer 1122 can be acrylate. In one embodiment, when three layers of the second connection layer 112 are made of thermoplastic materials, the materials of the three layers of the second connection layer 112 can be silicone resin, acrylate, and polyvinyl butyral respectively.

[0117] The present application also provides a specific implementation manner of a display module. Refer to Figure 7 As shown, the display module includes the display screen 11 described in any of the above embodiments, and further includes a support structure 12. Both the display screen 11 and the support structure 12 are in a plate shape, and the display screen 11 and the support structure 12 are stacked. The display screen 11 includes a surface layer 111, a polarizing layer 113, a display panel 114, and a back film 115 that are stacked and connected, and the support structure 12 is attached to the side of the back film 115 facing away from the display panel 114. The support structure 12 may include a fifth connection layer 121 and a support member 122, and the fifth connection layer 121 may fixedly attach the support member 122 to the back side of the display screen 11.

[0118] Refer to Figure 8 As shown, the support member 122 can be at least one layer, for example Figure 8 As shown in the double-layer structure. The support member 122 is composed of a layer of copper plate and a layer of steel plate stacked. Among them, the copper plate can be attached and fixed to the back film 115 through the fifth connection layer 121, and the back film 115, the fifth connection layer 121, the copper plate, and the steel plate are stacked in sequence. The double-layer structure of the support member 122 that communicates can form a connection interface between the copper plate and the steel plate. When the display screen is bent and prepared, the double-layer structure inside the support member 122 can undergo a certain degree of shear slip along the connection interface, which is beneficial to reducing the force on the display panel.

[0119] In one embodiment, refer to Figure 9 As shown, the positions of the steel plate and the copper plate can be interchanged. The steel plate can be attached and fixed to the back film 115 through the fifth connection layer 121, and the back film 115, the fifth connection layer 121, the steel plate, and the copper plate are stacked in sequence.

[0120] In one embodiment, the material of the back film 115 in the display screen 11 includes a thermoplastic material, which refers to a material that can be plasticized when heated to a certain temperature and solidified to increase hardness after the temperature decreases. The hardness of the thermoplastic material will decrease to be plasticizable after being heated to a certain temperature and will return to a solid state to maintain a high hardness after the temperature decreases. Moreover, the thermoplastic material is in an elastic state with plasticity at high temperature and in a glassy state with high hardness at low temperature, and the elastic state and the glassy state can be switched following the change of temperature.

[0121] In the embodiment of the present application, by designing the material of the back film 115 to include a thermoplastic material, and the glass transition temperature Tg of the thermoplastic material is in the range of 60 °C to 120 °C, and specifically can be selected according to the thermoforming temperature of the surface layer 111, so that the glass transition temperature Tg of the back film 115 is less than the thermoforming temperature of the surface layer 111. When the curved screen of the display module 10 is prepared, both the surface layer 111 and the back film 115 are softened to a certain extent by heating. In one embodiment, the Young's modulus of the thermoplastic material for preparing the back film 115 in the elastic state (when the temperature of the back film 115 is higher than its glass transition temperature Tg, the back film 115 is softened and becomes in the elastic state) is less than or equal to 800 MPa. At this strength, when the back film 115 is bent, it will not cause a relatively strong extrusion to the display panel 114. The surface layer 111 is bent and extrudes the display panel 114 and the back film 115, and the clamping force of the surface layer 111 and the back film 115 on the display panel 114 is small, reducing or even preventing the display panel 114 from wrinkling.

[0122] Moreover, the glass transition temperature Tg of the back film 115 is greater than or equal to 60 °C, so that the glass transition temperature of the back film 115 is higher than the ambient temperature when the display module 10 is in use. During the use process of the display module 10 after being bent and formed, both the surface layer 111 and the back film 115 have a certain hardness to protect the display panel 114 clamped in the middle. In one embodiment, the Young's modulus of the thermoplastic material for preparing the back film 115 in the glassy state (when the temperature of the back film 115 is lower than its glass transition temperature Tg, the back film 115 is hardened and becomes in the glassy state) is greater than 1000 MPa. At this hardness, the back film 115 can better support the display panel 114 when the display module 10 is in use, preventing the display panel 114 from deforming or even being damaged due to force.

[0123] In one embodiment, the material of the second connection layer 112 may include a thermoplastic material, specifically a thermoplastic resin. The glass transition temperature Tg of the second connection layer 112 may be in the range of 60 degrees Celsius to 120 degrees Celsius. The Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the elastic state is less than or equal to 100 MPa, and the Young's modulus of the thermoplastic material for preparing the second connection layer 112 in the glassy state is greater than 200 MPa.

[0124] In one embodiment, when preparing the display module 10, the thermoplastic resin heated to the elastic state may be first applied between the flat surface layer 111 and the polarizer layer 113, and a certain clamping force may be applied to the surface layer 111 and the polarizer layer 113. A certain bending force is applied to the areas that need to be bent, such as the edges and corners of the display module 10. Since the thermoplastic resin is in the elastic state, it can bend following the surface layer 111. Also, since the back film 115 is also a thermoplastic material and is in the elastic state at this temperature, and the polarizer layer 113 and the display panel 114 themselves do not have high hardness, the second connection layer 112, the polarizer layer 113, the display panel 114, and the back film 115 can all be bent well under the extrusion of the surface layer 111, and the layers are closely attached to each other. After bending to the set degree, the temperature is lowered, and the second connection layer 112 formed by the thermoplastic resin gradually cures and fixedly connects the surface layer 111 and the polarizer layer 113, and the back film 115 also cures to support the back side of the display panel 114. During the entire bending process, the display panel 114 will not be subjected to too much squeezing force on both sides, thereby reducing the degree of wrinkles, and even completely eliminating the wrinkles, improving the display effect of the display panel 114.

[0125] This application provides an electronic device 100. Refer to Figure 1 and Figure 2 As shown, it includes the display module 10 described in the above embodiment, and further includes a housing 20, and the housing 20 is connected to the display module 10. In this application, at least one of the back film 115 and the second connection layer 112 in the display screen 11 can be made of a thermoplastic material. When preparing the bent part of the display module 10 of the electronic device 100, one of the back film 115 and the second connection layer 112 can be in the elastic state with a smaller Young's modulus during bending, so as to reduce the extrusion on the display panel 114, reduce or even eliminate the wrinkles appearing on the display panel 114, and improve the display clarity of the electronic device 100.

[0126] The electronic device in this application may include, but is not limited to, products with a display interface such as mobile phones, tablet computers, laptop computers, ultra-mobile personal computers, handheld computers, walkie-talkies, Internet TVs, wearable devices, vehicle-mounted devices, dash cams, and security devices. The embodiments of this application do not make special restrictions on the form of the above electronic devices.

[0127] Exemplarily, please refer to Figure 1 , in the embodiment of the present application, the electronic device 100 is described by taking a curved screen mobile phone as an example. Figure 1 FIG. 4 is a three-dimensional schematic diagram of the electronic device 100 provided by the embodiment of the present application. Figure 2 FIG. 5 is a formal schematic diagram of the electronic device 100 provided by the embodiment of the present application. The electronic device 100 includes a display module 10 and a housing 20. The display module 10 is connected to the housing 20. The housing 20 may include a middle frame and a rear cover. The middle frame and the rear cover may be a split structure or an integral structure. The embodiments of the present application do not make specific limitations.

[0128] The display module 10 is installed on the housing 20. Among them, the housing 20 has a receiving cavity. Components such as the circuit board, electronic components, camera module, processor, and battery of the electronic device 100 can all be installed in the receiving cavity of the housing 20. The display module 10 covers the opening of the receiving cavity of the housing 20. The display module 10 and the housing 20 are hermetically connected to form a sealed receiving cavity to protect the components in the receiving cavity from water, dust, etc. The housing 20 can be made of materials such as metal (such as aluminum alloy, titanium alloy, and stainless steel), plastic (such as acrylonitrile-butadiene-styrene, polycarbonate, and polypropylene), or glass (such as anti-glare glass). The housing 20 made of materials such as metal, plastic, or glass can meet the requirements of wear resistance, impact resistance, corrosion resistance, and aesthetics of the appearance of the electronic device 100.

[0129] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A display screen, characterized in that, It includes a display panel and a back film connected in a stacked manner. The material of the back film includes a thermoplastic material. The glass transition temperature of the thermoplastic material is in the range of 60 °C to 120 °C. The Young's modulus of the thermoplastic material in the elastic state is less than or equal to 800 MPa, and the Young's modulus of the thermoplastic material in the glassy state is greater than 1000 MPa.

2. The display screen according to claim 1, characterized in that, The thermoplastic material includes at least one of polycarbonate, polyvinyl butyral, polypropylene, polyethylene, and polymethyl methacrylate.

3. The display screen according to claim 1 or 2, characterized in that, The back film includes at least two layers of back films stacked. The at least two layers of back films include a first back film, and the material of the first back film is the thermoplastic material.

4. The display layer according to claim 3, wherein, The at least two layers of back films include a second back film, and the materials of the first back film and the second back film are different thermoplastic materials.

5. The display screen according to any one of claims 1-4, characterized in that, The display screen further includes a first connection layer. The material of the first connection layer includes a pressure-sensitive material. The first connection layer is located between the display panel and the back film and fixedly connects the display panel and the back film.

6. The display screen according to any one of claims 1-5, characterized in that, The display screen further includes a stacked surface layer, a second connection layer, and an optical film layer. The second connection layer fixedly connects the surface layer and the optical film layer. The display panel is fixed between the optical film layer and the back film. The material of the second connection layer includes a thermoplastic material. The glass transition temperature of the thermoplastic material used to prepare the second connection layer is in the range of 60 °C to 120 °C. The Young's modulus of the thermoplastic material used to prepare the second connection layer in the elastic state is less than or equal to 100 kPa, and the Young's modulus of the thermoplastic material used to prepare the second connection layer in the glassy state is greater than 200 kPa.

7. The display screen according to claim 6, characterized in that, The 180-degree peel force of the second connection layer is greater than or equal to 1200 g / inch, and / or the vertical pull-out strength of the second connection layer is greater than or equal to 0.05 MPa.

8. The display screen according to claim 6 or 7, characterized in that, The thermoplastic material includes at least one of silicone resin, silicone rubber, polyvinyl butyral, and acrylate.

9. The display screen according to any one of claims 6-8, characterized in that, The second connection layer includes at least two layers of connection layers stacked. The at least two layers of connection layers include a third connection layer, and the material of the third connection layer is the thermoplastic material.

10. The display layer according to claim 9, wherein The at least two layers of connection layers include a fourth connection layer, and the materials of the third connection layer and the fourth connection layer are different thermoplastic materials.

11. A display screen, characterized in that, It includes a surface layer, a second connection layer, and an optical film layer stacked in sequence. The second connection layer fixedly connects the surface layer and the optical film layer. The material of the second connection layer includes a thermoplastic material. The glass transition temperature of the thermoplastic material is in the range of 60 °C to 120 °C. The Young's modulus of the thermoplastic material used to prepare the second connection layer in the elastic state is less than or equal to 100 kPa, and the Young's modulus of the thermoplastic material used to prepare the second connection layer in the glassy state is greater than 200 kPa.

12. The display screen according to claim 11, characterized in that, The 180-degree peel force of the second connection layer is greater than or equal to 1200 g / inch, and / or the vertical pull-out strength of the second connection layer is greater than or equal to 0.05 MPa.

13. The display screen according to claim 11 or 12, characterized in that, The manufacturing material of the second connection layer includes at least one of silicone resin, silicone rubber, polyvinyl butyral, and acrylate.

14. The display screen according to any one of claims 11-13, characterized in that, The second connection layer includes at least two connection layers arranged in a stacked manner, the at least two connection layers include a third connection layer, and the material of the third connection layer is the thermoplastic material.

15. The display layer according to claim 14, wherein, The at least two connection layers include a fourth connection layer, and the materials of the third connection layer and the fourth connection layer are different thermoplastic materials.

16. A display module, characterized in that, It includes the display screen and the support member according to any one of claims 1-15, and the support member is located inside the display screen to support the display screen.

17. An electronic device, characterized in that, It includes the display module according to claim 16, and further includes a housing, and the housing is fixedly connected to the outer peripheral edge of the display module.

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