Back film and preparation method thereof, display panel and preparation method thereof, display device

Abstract

Embodiments of the present disclosure provide a back film and a preparation method thereof, a display panel and a preparation method thereof, and a display device. The back film comprises a protective film, a back film main body layer and a release film which are sequentially stacked, the back film main body layer comprises a first back film part and a second back film part, the first back film part comprises a first area and a second area surrounding the first area, the first area is provided with a through hole, and the second back film part is accommodated in the through hole and is peelable.

Description

Technical Field

[0001] This disclosure relates to, but is not limited to, the field of display technology, and particularly to a back film and its preparation method, a display panel and its preparation method, and a display device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are active-matrix display devices with advantages such as self-illumination, wide viewing angle, high contrast, low power consumption, and extremely fast response speed. With the continuous development of display technology, flexible display devices that use OLEDs as light-emitting devices and thin-film transistors (TFTs) for signal control have become the mainstream products in the display field. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0004] In a first aspect, embodiments of this disclosure provide a backing film, comprising: a protective film, a backing film main layer, and a release film stacked sequentially, wherein the backing film main layer comprises: a first backing film portion and a second backing film portion, wherein the first backing film portion comprises: a first region and a second region surrounding the first region, wherein the first region has a through hole, and the second backing film portion is accommodated in the through hole and is peelable.

[0005] Secondly, this disclosure provides a method for preparing a backing film, characterized in that the backing film is as described in the above embodiments, and the preparation method includes: forming a first backing film portion and a second backing film portion, the first backing film portion including: a first region and a second region surrounding the first region, the first region having a through hole; forming a protective film on one side of the first backing film portion; accommodating the second backing film portion in the through hole; and forming a release film on the other side of the first backing film portion.

[0006] Thirdly, this disclosure provides a method for manufacturing a display panel, comprising: providing a display substrate and a back film as described in the above embodiments, wherein the display substrate includes an under-display camera area and a non-camera area surrounding the under-display camera area; removing the release film of the back film; attaching the back film to the non-display side of the display substrate, wherein a first back film portion of the back film is aligned with the non-camera area, and a second back film portion of the back film is aligned with the under-display camera area; attaching a cover glass to the display side of the display substrate by rolling; removing the protective film and the second back film portion of the back film, so that a through-hole in the first back film portion of the back film exposes the under-display camera area of ​​the display panel.

[0007] Fourthly, this disclosure provides a display panel, which is prepared using the display panel preparation method described in the above embodiments.

[0008] Fifthly, this disclosure provides a display device, including: the display panel described in the above embodiments and a camera, wherein the camera corresponds to a through hole in the back film and an under-display camera area of ​​the display panel.

[0009] The back film and its preparation method, the display panel and its preparation method, and the display device provided in this disclosure have through holes in the first back film portion and the second back film portion located in the through holes can be peeled off. Therefore, when the back film in this disclosure is used to protect the display substrate, it can eliminate water ripple defects and avoid wrinkle problems, thereby improving the imaging quality of under-display cameras.

[0010] Other features and advantages of this disclosure will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the disclosure. Other advantages of this disclosure may be realized and obtained by means of the methods described in the description and the accompanying drawings.

[0011] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects will become clear. Attached Figure Description

[0012] The accompanying drawings are provided to illustrate the technical solutions of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the technical solutions of this disclosure and do not constitute a limitation on the technical solutions of this disclosure. The shapes and sizes of the components in the drawings do not reflect actual proportions and are only intended to illustrate the content of this disclosure.

[0013] Figure 1 This is a schematic diagram of the planar structure of the backsheet in an exemplary embodiment of this disclosure;

[0014] Figure 2 for Figure 1 The diagram shows a cross-sectional structure of the backsheet along the A-A' direction.

[0015] Figure 3 for Figure 1 The diagram shows another cross-sectional structure of the backsheet along the A-A' direction;

[0016] Figure 4A This is a schematic diagram of a structure after forming a backsheet to be treated in an exemplary embodiment of the present disclosure;

[0017] Figure 4B This is a schematic diagram of a structure after perforating the backsheet to be processed in an exemplary embodiment of the present disclosure;

[0018] Figure 4C This is a schematic diagram of a structure after the formation of a new protective film in an exemplary embodiment of the present disclosure;

[0019] Figure 4D This is a schematic diagram of a structure after the second adhesive layer is bonded to the new protective film in an exemplary embodiment of the present disclosure;

[0020] Figure 4E This is a schematic diagram of a structure after forming a new release film in an exemplary embodiment of the present disclosure;

[0021] Figure 5A This is a schematic diagram of another structure after forming the backsheet to be treated in an exemplary embodiment of the present disclosure;

[0022] Figure 5B This is a schematic diagram of another structure after perforating the back film to be processed in an exemplary embodiment of the present disclosure;

[0023] Figure 5C This is a schematic diagram of another structure after the formation of a new protective film in an exemplary embodiment of this disclosure;

[0024] Figure 5D This is a schematic diagram of another structure after the second adhesive layer is bonded to the new protective film in an exemplary embodiment of this disclosure;

[0025] Figure 5E This is a schematic diagram of another structure after forming a new release film in an exemplary embodiment of this disclosure;

[0026] Figure 6 This is a schematic diagram of the structure of the display panel in an exemplary embodiment of this disclosure;

[0027] Figure 7A Forming a display substrate and in an exemplary embodiment of this disclosure Figure 2 The diagram shows the structure behind the back membrane.

[0028] Figure 7B This is a schematic diagram of a structure after the display substrate and back film are bonded together in an exemplary embodiment of the present disclosure.

[0029] Figure 7C This is a schematic diagram of a structure after the cover glass is formed in an exemplary embodiment of the present disclosure;

[0030] Figure 8A Forming a display substrate and in an exemplary embodiment of this disclosure Figure 3 The diagram shows the structure behind the back membrane.

[0031] Figure 8B This is a schematic diagram of another structure after the display substrate and back film are bonded together in an exemplary embodiment of the present disclosure;

[0032] Figure 8C This is a schematic diagram of another structure after the cover glass is formed in an exemplary embodiment of this disclosure;

[0033] Figure 9 This is a schematic diagram of the structure of a display device in an exemplary embodiment of this disclosure. Detailed Implementation

[0034] This document describes several embodiments, but these descriptions are exemplary and not limiting. Many more embodiments and implementations are possible within the scope of the embodiments described herein. Although many possible combinations of features are shown in the accompanying drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in conjunction with, or may replace, any other feature or element of any other embodiment.

[0035] In describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that it does not depend on such a specific order. Other sequences of steps are possible, as will be understood by those skilled in the art. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation of the claims. Furthermore, the claims relating to the method and / or process should not be limited to the steps performed in the order written, and those skilled in the art will readily understand that these orders may be varied and still remain within the spirit and scope of the embodiments disclosed herein.

[0036] In the accompanying drawings, the size of each component, the thickness of a layer, or the area are sometimes exaggerated for clarity. Therefore, this disclosure is not necessarily limited to these dimensions, and the shape and size of each part in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate ideal examples, and this disclosure is not limited to the shapes or values ​​shown in the drawings.

[0037] In the exemplary embodiments disclosed herein, the terms "first," "second," "third," and similar terms are used to avoid confusion of constituent elements, rather than to limit them in terms of quantity, order, or importance.

[0038] In exemplary embodiments of this disclosure, the words “comprising” or “including” and similar terms mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0039] In the exemplary embodiments of this disclosure, for convenience, terms such as "middle," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," indicating orientation or positional relationship, are used to describe the positional relationship of constituent elements with reference to the accompanying drawings. This is solely for the purpose of facilitating the description of this specification and simplifying the description, and is not intended to indicate or imply that the device or element referred to has a specific orientation, or is constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this disclosure. The positional relationship of the constituent elements may be appropriately changed depending on the direction in which each constituent element is described. Therefore, the description is not limited to the terms used in the specification and may be appropriately replaced as appropriate.

[0040] In the exemplary embodiments disclosed herein, unless otherwise expressly specified and limited, the terms "connected," "linked," "installed," and similar words should be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection, an indirect connection via an intermediate component, or a connection within two components. Those skilled in the art will understand the meaning of the above terms in this disclosure as appropriate.

[0041] In exemplary embodiments of this disclosure, "electrical connection" includes the case where constituent elements are connected together by an element having some electrical function. There are no particular limitations on the "electrical function" as long as it enables the transmission and reception of electrical signals between the connected constituent elements. The "electrical function" can be, for example, an electrode or wiring, a switching element such as a transistor, or other functional elements such as a resistor, inductor, or capacitor.

[0042] In exemplary embodiments of this disclosure, a transistor is a device that includes at least three terminals: a gate electrode (gate or control electrode), a drain electrode (drain electrode terminal, drain region, or drain electrode), and a source electrode (source electrode terminal, source region, or source electrode). The transistor has a channel region between the drain electrode and the source electrode, and current can flow through the drain electrode, the channel region, and the source electrode. Note that in this specification, the channel region refers to the region through which current primarily flows.

[0043] In exemplary embodiments of this disclosure, to distinguish the two terminals of a transistor other than the gate electrode (gate or control electrode), one terminal is directly described as the first terminal and the other as the second terminal. The first terminal can be the drain electrode and the second terminal can be the source electrode, or vice versa. In cases where transistors with opposite polarities are used or where the current direction changes during circuit operation, the functions of the "source electrode" and "drain electrode" are sometimes interchanged. Therefore, in this specification, the "source electrode" and "drain electrode" can be interchanged.

[0044] In the exemplary embodiments of this disclosure, the transistor can be a thin film transistor (TFT), a field effect transistor (FET), or other devices with similar characteristics. For example, the thin film transistor used in the embodiments of this disclosure may include, but is not limited to, oxide TFTs or low-temperature poly-silicon TFTs (LTPS TFTs). This disclosure does not limit the scope of the application.

[0045] In the exemplary embodiments of this disclosure, "parallel" can refer to a state in which the angle formed by two straight lines is greater than or equal to -10° and less than 10°, and therefore may also include a state in which the angle is greater than or equal to -5° and less than 5°. In addition, "perpendicular" can refer to a state in which the angle formed by two straight lines is greater than or equal to 80° and less than 100°, and therefore may also include a state in which the angle is greater than or equal to 85° and less than 95°.

[0046] In exemplary embodiments of this disclosure, "about" may refer to a value that is not strictly limited and allows for process and measurement errors.

[0047] In the exemplary embodiments of this disclosure, the first direction DR1 may refer to the thickness direction of the back film or a direction perpendicular to the back film plane, etc. The second direction DR2 may refer to the extension direction of the scan signal line (also known as a gate line) in the display area or the row direction, etc., and the third direction DR3 may refer to the extension direction of the data signal line (also known as a data line) in the display area or the column direction, etc., wherein the first direction DR1 intersects the second direction DR2, and the second direction DR2 intersects the third direction DR3. For example, the first direction DR1 and the second direction DR2 may be perpendicular to each other, and the second direction DR2 and the third direction DR3 may be perpendicular to each other. Here, the embodiments of this disclosure do not limit this.

[0048] In under-display camera (FDC) technology, a back film (BF), also known as a back protector or rear protective film, is usually used to protect the display substrate. However, water ripple defects and wrinkle problems may occur, resulting in a decrease in the imaging quality of the under-display camera.

[0049] According to Fresnel's law of refraction (also known as the Fresnel Formula), the lens element (e.g., glass or acrylic) in a camera acts as a polarizer (e.g., an analyzer), polarizing unpolarized light as it passes through the glass. The inventors of this disclosure have discovered that in a sandwich structure formed by natural light passing through the polarizer (POL, equivalent to a polarizer) of an FDC (Fiber-Coupled Device), the back film, and the lens element (equivalent to an analyzer) in a camera, the polarized light is prone to interference at large field-of-view angles due to the phase difference between the polarizer and the back film. This interference results in water ripples when imaged on image sensors such as charge-coupled devices (CCDs) or complementary metal-oxide-semiconductor (CMOS). While partially hollowing out the portion of the back film corresponding to the under-display camera area on the display substrate can improve the water ripple effect, the pressure during cover glass (CG) roll bonding can deform the camera area, easily causing wrinkles on the display substrate. This reduces image resolution and degrades the image quality of the under-display camera.

[0050] This disclosure provides a backing membrane. Figure 1 This is a schematic diagram of the planar structure of the backsheet in an exemplary embodiment of the present disclosure. Figure 2 for Figure 1 The diagram shows a cross-sectional structure of the backsheet along the A-A' direction. Figure 3 for Figure 1 The diagram shows another cross-sectional structure of the backsheet along the A-A' direction. (See attached diagram.) Figures 1 to 3 As shown, in a plane perpendicular to the back film, the back film may include: a protective film 10, a back film main layer 20, and a release film 30 sequentially stacked along the first direction DR1. The back film main layer 20 may include: a first back film portion 21 and a second back film portion 22. In a plane parallel to the back film, the first back film portion 21 may include: a first region 211 and a second region 212 surrounding the first region 211. The first region 211 has a through hole, and the second back film portion 22 can be accommodated within the through hole and is peelable. Here, in Figures 1 to 3 The illustration is based on the example where the shape and size of the through hole are the same as the shape and size of the first region 211, but it is not limited to this. For example, the shape of the first region 211 may be different from the shape of the through hole, or the size of the first region 211 may be larger than the size of the through hole.

[0051] In one exemplary embodiment, the second back film portion is configured to provide support for the under-display camera area of ​​the display panel when the back film is attached to the display panel and the second back film portion is not peeled off; or, after the back film is attached to the display panel and the second back film portion is peeled off, to expose the under-display camera area of ​​the display panel through the via.

[0052] Thus, when the back film in this embodiment is used to protect the display substrate, since the first back film portion has a through hole and the second back film portion located in the through hole is peelable, on the one hand, during the roll-pressing and bonding process of the cover glass, the second back film portion can be left unpeeled. The second back film portion provides support for the under-display camera area in the display substrate, ensuring consistent stress on both the under-display camera area and non-camera areas. This improves the deformation problem of the under-display camera area, thereby avoiding wrinkles and reduced image resolution. On the other hand, after the cover glass is roll-pressed and bonded, the second back film portion can be peeled off, exposing the under-display camera area in the display substrate through the through hole. This avoids interference and eliminates water ripple defects. Furthermore, this improves the imaging quality of the under-display camera.

[0053] In one exemplary embodiment, such as Figure 2 As shown, the stacking order of the multilayer films in the second back film portion 22 can be the same as the stacking order of the multilayer films in the first back film portion 21.

[0054] In one exemplary embodiment, such as Figure 2 As shown, the first back film portion 21 may include: a first support layer 213 disposed on the side of the protective film 10 near the release film 30, and a first adhesive layer 214 disposed on the side of the first support layer 213 near the release film 30. The second back film portion 22 may include: a second support layer 221 disposed on the side of the protective film 10 near the release film 30, and a second adhesive layer 222 disposed on the side of the second support layer 221 near the release film 30. The adhesiveness of the second adhesive layer 222 is lower than that of the first adhesive layer 214; for example, the second adhesive layer 222 may be non-adhesive.

[0055] In one exemplary embodiment, such as Figure 3 As shown, the stacking order of the multilayer films in the second back film portion 22 is the opposite of the stacking order of the multilayer films in the first back film portion 21.

[0056] In one exemplary embodiment, such as Figure 3As shown, the first back film portion 21 may include: a first support layer 213 disposed on the side of the protective film 10 near the release film 30, and a first adhesive layer 214 disposed on the side of the first support layer 213 near the release film 30. The second back film portion 22 may include: a second adhesive layer 222 disposed on the side of the protective film 10 near the release film 30, and a second support layer 221 disposed on the side of the second adhesive layer 222 near the release film 30. The adhesiveness of the second adhesive layer 222 is the same as that of the first adhesive layer 214. Thus, after removing the release layer, when the back film is attached to the display substrate, the first back film portion 21 can be adhered to the display substrate by the adhesiveness of the first adhesive layer 214. The second back film portion 22 can be adhered to the protective film 10 by the adhesiveness of the second adhesive layer 222, so that the second back film portion 22 can be directly peeled off by removing the protective film 10.

[0057] In one exemplary embodiment, the first support layer and the second support layer may be formed, but are not limited to, using polyethylene terephthalate (PET) material. Of course, other materials capable of providing support may also be used. They may be single-layer, multi-layer, or composite layers. This disclosure does not limit the specific application of these methods.

[0058] In one exemplary embodiment, the first adhesive layer and the second adhesive layer may be formed using, but are not limited to, pressure-sensitive adhesive (PSA) materials. Of course, other materials capable of adhesive bonding may also be used. This disclosure does not limit the scope of the embodiments described herein.

[0059] In one exemplary embodiment, the shape of the through hole can be any one of a rectangle, a circle, and an ellipse. Of course, the shape of the through hole can be other polygons. Here, the embodiments of this disclosure do not limit it in this way.

[0060] In one exemplary embodiment, when the through-hole is circular, the diameter of the circle can be approximately 3mm to 5mm. Similarly, when the through-hole is rectangular, the side length of the rectangle can be approximately 3mm to 5mm. This disclosure does not limit the specific shape of the through-hole.

[0061] In one exemplary embodiment, the release film may be formed of materials such as polyimide (PI) or polyethylene terephthalate (PET). It may be a single layer, multiple layers, or a composite layer. This disclosure does not limit the specific type of release film.

[0062] In one exemplary embodiment, the protective film may be formed using a material such as polyimide (PI). It may be a single layer, multiple layers, or a composite layer. This disclosure does not limit the specific application of this method.

[0063] The following is based on Figure 2 Taking the backsheet structure shown as an example, the structure and preparation process of the backsheet provided in the exemplary embodiments of this disclosure will be described in conjunction with the accompanying drawings.

[0064] In one exemplary embodiment, the method for preparing the backsheet may include the following steps:

[0065] Step 41: As Figure 4A As shown, an initial protective film 401, a support layer 402 located on one side of the initial protective film 401, an adhesive layer 403 located on the side of the support layer 402 away from the initial protective film 401, and an initial release film 404 located on the side of the adhesive layer 403 away from the initial protective film 401 are formed sequentially along the first direction DR1, thus forming the back film 40 to be processed.

[0066] In one exemplary embodiment, the initial protective film may be formed using a material such as PI.

[0067] In one exemplary embodiment, the support layer may be formed of PET material.

[0068] In one exemplary embodiment, the adhesive layer may be formed using PSA material.

[0069] In one exemplary embodiment, the initial release film may be formed from materials such as PI or PET.

[0070] Step 42: As Figures 4A to 4B As shown, the back film 40 to be processed is perforated by laser cutting to obtain a first sub-back film 406 and a second sub-back film 405. The first sub-back film 406 has through holes and may include a first protective film 401-1, a first support layer 213, a first adhesive layer 214 and a first release film 404-1 stacked sequentially along the first direction DR1. The second sub-back film 405 may include a second protective film 401-2, a second support layer 221, a second adhesive layer 222 and a second release film 404-2 stacked sequentially along the first direction DR1.

[0071] Step 43: As Figure 4CAs shown, the first protective film 401-1 and the first release film 404-1 in the first sub-back film 406 are removed to form the first back film portion 21, wherein the first back film portion 21 may include: a first support layer 213 and a first adhesive layer 214 sequentially stacked along the first direction DR1; the second protective film 401-2 and the second release film 404-2 in the second sub-back film 405 are removed to form the second back film portion 22, wherein the second back film portion 22 may include: a second support layer 221 and a second adhesive layer 222 sequentially stacked along the first direction DR1; and a new protective film 407 is attached, wherein the new protective film 407 is attached to the first support layer 213 and the second support layer 221.

[0072] Here, the new protective film 407 serves as the protective film 10 in the final formed backing film.

[0073] Step 44: As Figure 4D As shown, the adhesiveness of the second adhesive layer 222 is reduced by laser ablation or chemical ablation, making the adhesiveness of the second adhesive layer 222 lower than that of the first adhesive layer 214; for example, the second adhesive layer 222 becomes non-adhesive. This facilitates the peeling off of the second back film portion 22 during subsequent display panel fabrication.

[0074] Step 45: As Figure 4E As shown, a new release film 408 is attached, wherein the new release film 408 is attached to the side of the first adhesive layer 214 and the second adhesive layer 222 after de-adhesion, away from the new protective film 407.

[0075] Here, the new release film 408 serves as the release film 30 in the final formed backing film.

[0076] This completes the task. Figure 2 Preparation of the backsheet shown.

[0077] The following is based on Figure 3 Taking the backsheet structure shown as an example, the structure and preparation process of the backsheet provided in the exemplary embodiments of this disclosure will be described in conjunction with the accompanying drawings.

[0078] In one exemplary embodiment, the method for preparing the backsheet may include the following steps:

[0079] Step 51: As Figure 5A As shown, an initial protective film 401, a support layer 402 located on one side of the initial protective film 401, an adhesive layer 403 located on the side of the support layer 402 away from the initial protective film 401, and an initial release film 404 located on the side of the adhesive layer 403 away from the initial protective film 401 are formed sequentially along the first direction DR1, thus forming the back film 40 to be processed.

[0080] Step 52: As Figures 5A to 5B As shown, the back film 40 to be processed is punched by punching to obtain a first sub-back film 406 and a second sub-back film 405. The first sub-back film 406 has through holes and may include a first protective film 401-1, a first support layer 213, a first adhesive layer 214 and a first release film 404-1 stacked sequentially along the first direction DR1. The second sub-back film 405 may include a second protective film 401-2, a second support layer 221, a second adhesive layer 222 and a second release film 404-2 stacked sequentially along the first direction DR1.

[0081] Step 53: As Figure 5C As shown, the first protective film 401-1 in the first sub-back film 406 is removed, and a new protective film 407 is attached. The new protective film 407 is attached to the side of the first support layer 213 away from the first release film 404-1. Here, the new protective film 407 serves as the protective film 10 in the final formed back film.

[0082] Step 54: As Figures 5C to 5D As shown, the second release film 404-2 in the second sub-back film 405 is removed, and the second sub-back film 405 is flipped over. The flipped second sub-back film 405 is then placed into the through hole and pressed, so that the second adhesive layer 222 in the second sub-back film 405 is fully bonded to the new protective film 407. The adhesiveness of the second adhesive layer 222 is the same as that of the first adhesive layer 214.

[0083] Step 55: As Figures 5D to 5E As shown, the first release film 404-1 in the first sub-back film 406 is removed, the second protective film 401-2 in the second sub-back film 405 is removed, and a complete new release film 408 is attached, wherein the new release film 408 is attached to the first adhesive layer 214 and the second support layer 221.

[0084] Here, the new release film 408 serves as the release film 30 in the final formed backing film.

[0085] This completes the task. Figure 3 Preparation of the backsheet shown.

[0086] This disclosure also provides a method for preparing a backsheet, wherein the backsheet is the backsheet described in one or more of the above embodiments. The method for preparing the backsheet may include:

[0087] Step 61: Form a first back film portion and a second back film portion. The first back film portion may include: a first region and a second region surrounding the first region. The first region has a through hole.

[0088] Step 62: Form a protective film on one side of the first back membrane portion;

[0089] Step 63: Place the second back membrane portion into the through hole;

[0090] Step 64: Form a release film on the other side of the first back film portion.

[0091] In an exemplary embodiment, step 61 may include: forming a back film to be processed, wherein the back film to be processed may include: a protective film, a support layer, an adhesive layer, and a release film stacked sequentially; punching holes in the back film to be processed by laser cutting or punching to obtain a first sub-back film and a second sub-back film, wherein the first sub-back film has through holes and may include: a first protective film, a first support layer, a first adhesive layer, and a first release film stacked sequentially; the second sub-back film may include: a second protective film, a second support layer, a second adhesive layer, and a second release film stacked sequentially; removing the first protective film and the first release film from the first sub-back film to form a first back film portion, the first back film portion may include: a first support layer and a first adhesive layer stacked sequentially; removing the second protective film and the second release film from the second sub-back film to form a second back film portion, the second back film portion may include: a second support layer and a second adhesive layer stacked sequentially.

[0092] In one exemplary embodiment, step 63 may include: attaching a second support layer to the protective film, or attaching a second adhesive layer to the protective film so that the second back film portion is accommodated in the through hole.

[0093] In one exemplary embodiment, step 64 may include: reducing the adhesiveness of the second adhesive layer by laser ablation or chemical reagent ablation, and forming a release film that adheres to the first adhesive layer and the second adhesive layer; or, forming a release film that adheres to the first adhesive layer and the second support layer.

[0094] The descriptions of the above preparation method embodiments are similar to those of the above back film embodiments, and have similar beneficial effects. For technical details not disclosed in the preparation method embodiments of this disclosure, those skilled in the art should refer to the descriptions in the back film embodiments of this disclosure for understanding, and will not be repeated here.

[0095] This disclosure provides a display panel, Figure 6 This is a schematic diagram of the structure of the display panel in an exemplary embodiment of this disclosure, as shown below. Figure 6As shown, the display panel may include: a display substrate 50, a cover glass 60 located on the display side of the display substrate 50, and a back film 70 located on the non-display side of the display substrate 50. The display substrate 50 may include: a display area and a peripheral area surrounding the display area. The display area may include: an under-display camera area 501 and a non-camera area 502 surrounding the under-display camera area 501. Both the under-display camera area 501 and the non-camera area 502 may include a plurality of pixels arranged in a regular pattern. The back film 70 may include: a first back film portion 21. The first back film portion 21 may include: a first support layer 213 and a first adhesive layer 214 sequentially stacked along a first direction DR1. The first back film portion 21 has a through hole 701, which may correspond to the under-display camera area 501.

[0096] In one exemplary embodiment, the resolution of the under-display camera area 501 may be lower than the resolution of the non-camera area 502. Resolution (Pixels Per Inch, PPI) refers to the number of pixels per unit area, also known as pixel density. The higher the PPI value, the higher the density at which the display substrate can display the image, and the richer the details of the image.

[0097] In one exemplary embodiment, the under-display camera area 501 may correspond to the position of an optical sensor such as a camera, a fingerprint recognition device, or a 3D imaging device, and has the function of displaying images and transmitting light, wherein the transmitted light can be received by the optical sensor.

[0098] In one exemplary embodiment, the shape of the under-display camera area 501 in a plane parallel to the display substrate can be any of the following: rectangular, polygonal, circular, and elliptical. For example, when the shape of the under-display camera area 501 is circular, the diameter of the circle can be approximately 3mm to 5mm. Similarly, when the shape of the under-display camera area 501 is rectangular, the side length of the rectangle can be approximately 3mm to 5mm.

[0099] In one exemplary embodiment, the cover glass can be attached to the display substrate using a solid OCA optical adhesive or a liquid OCR optical adhesive.

[0100] In one exemplary embodiment, on a plane perpendicular to the display substrate, the display substrate may include: a substrate, a driving circuit layer disposed on the substrate, a light-emitting structure layer disposed on the side of the driving circuit layer away from the substrate, and an encapsulation layer disposed on the side of the light-emitting structure layer away from the substrate.

[0101] In one exemplary embodiment, the cover glass may be disposed on the side of the encapsulation layer in the display substrate away from the substrate. The back film may be disposed on the side of the substrate of the display substrate away from the encapsulation layer.

[0102] In one exemplary embodiment, the encapsulation layer may include: a first encapsulation layer, a second encapsulation layer and a third encapsulation layer stacked together. The first encapsulation layer and the third encapsulation layer may be made of inorganic materials, while the second encapsulation layer 4 may be made of organic materials. The second encapsulation layer is disposed between the first encapsulation layer and the third encapsulation layer to ensure that external moisture cannot enter the light-emitting structure layer.

[0103] In one exemplary embodiment, the substrate may be a flexible substrate. For example, the flexible substrate may be formed using a PI material.

[0104] In one exemplary embodiment, the driving circuit layer for each sub-pixel may include a plurality of transistors and a storage capacitor constituting the pixel driving circuit.

[0105] In one exemplary embodiment, the light-emitting structure layer may include: an anode, a pixel definition layer, an organic light-emitting layer, and a cathode. The anode is connected to the drain electrode of the driving transistor through a via, the organic light-emitting layer is connected to the anode, and the cathode is connected to the organic light-emitting layer. The organic light-emitting layer emits light of a corresponding color under the driving of the anode and cathode. For example, the organic light-emitting layer may include a stacked hole injection layer (HIL), a hole transport layer (HTL), an electron block layer (EBL), an emitting layer (EML), a hole block layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL).

[0106] The following is based on Figure 2 Taking the back film structure shown as an example, the structure and fabrication process of the display panel provided in the exemplary embodiments of this disclosure will be described in conjunction with the accompanying drawings.

[0107] In one exemplary embodiment, the method for manufacturing a display panel may include the following steps:

[0108] Step 71: As Figure 7A As shown, a display substrate 50 is formed, and a back film 70 is formed through steps 41 to 45. The through holes and the second back film portion 22 in the back film 70 are aligned with the under-display camera area 501 in the display substrate 50, and the first back film portion 21 is aligned with the non-camera area 502 in the display substrate 50.

[0109] The display substrate 50 may include an under-display camera area 501 and a non-camera area 502 surrounding the under-display camera area 501. The back film 70 may include a protective film 10, a back film main layer 20, and a release film 30 sequentially stacked along a first direction DR1. The back film main layer 20 may include a first back film portion 21 and a second back film portion 22. The first back film portion 21 may include a first support layer 213 and a first adhesive layer 214 sequentially stacked along the first direction DR1. The first back film portion 21 has a through hole 701. The second back film portion 22 may include a second support layer 221 and a second adhesive layer 222 sequentially stacked along the first direction DR1. The second back film portion 22 is located in the through hole.

[0110] Step 72: As Figure 7B As shown, the release film 30 of the back film 70 is removed, and the back film 70 is attached to the non-display side of the display substrate 50.

[0111] Step 73: As Figure 7C As shown, the cover glass 60 is attached to the display side of the display substrate 50 by roll forming. Thus, during the roll forming process of the cover glass 60, since the under-display camera area 501 still has the support provided by the second back film portion 22, the force on the under-display camera area 501 and the non-camera area 502 is consistent. Therefore, wrinkling and deformation of the display substrate 50 during the roll forming of the cover glass 60 can be avoided, thereby preventing the problem of reduced image resolution.

[0112] Step 74: As Figure 6 As shown, the protective film 10 of the back film 70 is removed to peel off the second back film portion 22. Thus, since the second adhesive layer 222 in the second back film portion 22 corresponding to the under-display camera area 501 has undergone anti-adhesion treatment and is no longer adhesive, but the second support layer 221 and the protective film 10 are still adhesive, the second support layer 221 and the second adhesive layer 222 in the second back film portion 22 corresponding to the under-display camera area 501 are removed together with the protective film 10. Furthermore, in the completed display panel, the through-hole 701 of the first back film portion 21 can expose the under-display camera area 501, avoiding interference and eliminating water ripple defects.

[0113] Thus, through Figure 2 The backsheet preparation shown is complete. Figure 6 The display panel shown.

[0114] The following is based on Figure 3 Taking the back film structure shown as an example, the structure and fabrication process of the display panel provided in the exemplary embodiments of this disclosure will be described in conjunction with the accompanying drawings.

[0115] In one exemplary embodiment, the method for manufacturing a display panel may include the following steps:

[0116] Step 81: As Figure 8A As shown, a display substrate 50 is formed, and a back film 70 is formed through steps 41 to 45. The through holes and the second back film portion 22 in the back film 70 can be aligned with the under-display camera area 501 in the display substrate 50, and the first back film portion 21 is aligned with the non-camera area 502 in the display substrate 50.

[0117] The display substrate 50 may include an under-display camera area 501 and a non-camera area 502 surrounding the under-display camera area 501. The back film 70 may include a protective film 10, a back film main layer 20, and a release film 30 sequentially stacked along a first direction DR1. The back film main layer 20 may include a first back film portion 21 and a second back film portion 22. The first back film portion 21 may include a first support layer 213 and a first adhesive layer 214 sequentially stacked along the first direction DR1. The first back film portion 21 has a through hole 701. The second back film portion 22 may include a second adhesive layer 222 and a second support layer 221 sequentially stacked along the first direction DR1. The second back film portion 22 is located in the through hole.

[0118] Step 82: As Figure 8B As shown, the release film 30 of the back film 70 is removed, and the back film 70 is attached to the non-display side of the display substrate 50. The first adhesive layer 214 of the first back film portion 21 is fully bonded to the display substrate 50, while the second support layer 221 of the second back film portion 22 has no adhesive relationship with the display substrate 50 and only serves a supporting function.

[0119] Step 83: As Figure 8C As shown, the cover glass 60 is attached to the display side of the display substrate 50 by roll forming. Thus, during the roll forming process of the cover glass 60, since the under-display camera area 501 still has the support provided by the second back film portion 22, the force on the under-display camera area 501 and the non-camera area 502 is consistent. Therefore, wrinkling and deformation of the display substrate 50 during the roll forming of the cover glass 60 can be avoided, thereby preventing the problem of reduced image resolution.

[0120] Step 84: As Figure 6As shown, the protective film 10 of the back film 70 is removed to peel off the second back film portion 22. Thus, in the second back film portion 22 corresponding to the under-display camera area 501, due to the adhesiveness of the second adhesive layer 222, there is adhesion between the second adhesive layer 222 and the protective film 10, and also between the second adhesive layer 222 and the second support layer 221. Therefore, the second support layer 221 and the second adhesive layer 222 in the second back film portion 22, along with the protective film 10, are removed together. Furthermore, in the completed display panel, the through-hole 701 of the first back film portion 21 can expose the under-display camera area 501, avoiding interference and eliminating water ripple defects.

[0121] Thus, through Figure 3 The backsheet preparation shown is complete. Figure 6 The display panel shown.

[0122] This disclosure also provides a method for manufacturing a display panel, which may include: providing a display substrate and a back film as described in one or more of the above embodiments, wherein the display substrate may include an under-display camera area and a non-camera area surrounding the under-display camera area; removing the release film of the back film; attaching the back film to the non-display side of the display substrate, wherein a first back film portion of the back film is aligned with the non-camera area and a second back film portion of the back film is aligned with the under-display camera area; attaching a cover glass to the display side of the display substrate by rolling; and removing the protective film and the second back film portion of the back film to expose the under-display camera area of ​​the display panel through a through-hole in the first back film portion of the back film.

[0123] As can be seen from the above, when manufacturing a display panel using the method described in this embodiment, on the one hand, during the roll-pressing and bonding process of the cover glass, the second back film provides support for the under-display camera area in the display substrate, ensuring consistent stress on both the under-display camera area and the non-camera area. This improves the deformation problem of the under-display camera area, thereby avoiding wrinkles and reduced image resolution. On the other hand, after the cover glass is roll-pressed and bonded, the second back film is peeled off, exposing the under-display camera area in the display substrate through the vias. This avoids interference and eliminates water ripple defects. Furthermore, this improves the imaging quality of the under-display camera.

[0124] This disclosure also provides a display panel. The display panel is manufactured using the display panel manufacturing method described in one or more of the above embodiments.

[0125] In one exemplary embodiment, the display panel may be an OLED display panel.

[0126] Furthermore, in addition to the structures described above, the display panel in this embodiment may also include other necessary components and structures, such as scan signal lines or TFT substrates. Those skilled in the art can make corresponding designs and additions depending on the type of display panel, which will not be elaborated upon here and should not be construed as limiting this disclosure.

[0127] This disclosure also provides a display device. Figure 9 This is a schematic diagram of the structure of the display device in an exemplary embodiment of the present disclosure, such as... Figure 9 As shown, the display device may include: the display panel 901 in one or more of the above embodiments and the camera 902, the camera 902 corresponding to the through hole 701 and the under-screen camera area 501.

[0128] In one exemplary embodiment, the display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, or navigator. Here, this disclosure does not limit the type of display device. Other essential components of the display device are those that should be understood by those skilled in the art, and will not be described in detail here, nor should they be construed as limiting this disclosure.

[0129] In one exemplary embodiment, the display device is an electroluminescent display device. For example, the electroluminescent display device may be an OLED display device or a quantum dot electroluminescent display device (QLED).

[0130] The description of the above display device embodiments is similar to the description of the above back film and display panel embodiments, and has similar beneficial effects. For technical details not disclosed in the display device embodiments of this disclosure, please refer to the description of the back film and display panel embodiments of this disclosure for understanding. Further details will not be repeated here.

[0131] While the embodiments disclosed herein are as described above, the above content is merely for the purpose of facilitating understanding of this disclosure and is not intended to limit this disclosure. Any person skilled in the art to which this disclosure pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed herein, but the scope of patent protection of this disclosure shall still be determined by the scope defined in the appended claims.

Claims

1. A backsheet, characterized in that, include: A protective film, a backing film main layer, and a release film are stacked sequentially. The backing film main layer includes a first backing film portion and a second backing film portion. The first backing film portion includes a first region and a second region surrounding the first region. The first region has a through hole, and the second backing film portion is accommodated in the through hole and can be peeled off. The stacking order of the multilayer films in the second back film portion is the same as that in the first back film portion.

2. The backsheet according to claim 1, characterized in that, The second back film portion is configured to provide support for the under-display camera area of ​​the display panel when the back film is attached to the display panel and the second back film portion is not peeled off; or, after the back film is attached to the display panel and the second back film portion is peeled off, to expose the under-display camera area of ​​the display panel through the through hole.

3. The backsheet according to claim 1 or 2, characterized in that, The first back film portion includes: a first support layer disposed on the protective film near the release film side and a first adhesive layer disposed on the first support layer near the release film side; the second back film portion includes: a second support layer disposed on the protective film near the release film side and a second adhesive layer disposed on the second support layer near the release film side; the adhesiveness of the second adhesive layer is lower than that of the first adhesive layer.

4. The backsheet according to claim 3, characterized in that, The first support layer and the second support layer are formed of polyethylene terephthalate (PET) material.

5. The backsheet according to claim 3, characterized in that, The first adhesive layer and the second adhesive layer are formed using pressure-sensitive adhesive (PSA) material.

6. The backsheet according to claim 1, characterized in that, The shape of the through hole can be any one of rectangle, circle, or ellipse.

7. A backsheet, characterized in that, include: A protective film, a backing film main layer, and a release film are stacked sequentially. The backing film main layer includes a first backing film portion and a second backing film portion. The first backing film portion includes a first region and a second region surrounding the first region. The first region has a through hole, and the second backing film portion is accommodated in the through hole and can be peeled off. Wherein, the stacking order of the multilayer film in the second back film portion is the opposite of the stacking order of the multilayer film in the first back film portion; The first back film portion includes: a first support layer disposed on the protective film near the release film side and a first adhesive layer disposed on the first support layer near the release film side; the second back film portion includes: a second adhesive layer disposed on the protective film near the release film side and a second support layer disposed on the second adhesive layer near the release film side; the adhesiveness of the second adhesive layer is the same as that of the first adhesive layer. The first adhesive layer and the second adhesive layer have the same material and thickness.

8. A method for preparing a backsheet, characterized in that, The backsheet is the backsheet as described in any one of claims 1 to 7, and the preparation method includes: A first back film portion and a second back film portion are formed. The first back film portion includes: a first region and a second region surrounding the first region. The first region has a through hole. A protective film is formed on one side of the first back membrane portion; The second back film portion is accommodated in the through hole; A release film is formed on the other side of the first back film portion.

9. The method according to claim 8, characterized in that, The formation of the first back membrane portion and the second back membrane portion includes: A back film to be processed is formed, wherein the back film to be processed comprises: a protective film, a support layer, an adhesive layer and a release film stacked in sequence; The back film to be processed is perforated by laser cutting or punching to obtain a first sub-back film and a second sub-back film. The first sub-back film has through holes and includes a first protective film, a first support layer, a first adhesive layer and a first release film stacked in sequence. The second sub-back film includes a second protective film, a second support layer, a second adhesive layer and a second release film stacked in sequence. Remove the first protective film and the first release film from the first sub-back film to form the first back film portion, the first back film portion comprising: a first support layer and a first adhesive layer stacked together; The second protective film and the second release film in the second sub-back film are removed to form the second back film portion, which includes: a second support layer and a second adhesive layer stacked together.

10. The method according to claim 9, characterized in that, The step of accommodating the second back film portion within the through hole includes: The second support layer is attached to the protective film, or the second adhesive layer is attached to the protective film so that the second back film portion is accommodated in the through hole.

11. The method according to claim 9, characterized in that, The step of forming a release film on the other side of the first back film portion includes: The adhesiveness of the second adhesive layer is reduced by laser ablation or chemical ablation, and a release film is formed that adheres to the first adhesive layer and the second adhesive layer. Alternatively, a release film can be formed that adheres to the first adhesive layer and the second support layer.

12. A method for manufacturing a display panel, characterized in that, include: A display substrate and a back film as described in any one of claims 1 to 7 are provided, wherein the display substrate includes: an under-display camera area and a non-camera area surrounding the under-display camera area; Remove the release film from the backing film; The back film is attached to the non-display side of the display substrate, wherein the first back film portion of the back film is aligned with the non-camera area, and the second back film portion of the back film is aligned with the under-display camera area; The cover glass is attached to the display side of the display substrate by rolling. Remove the protective film and the second back film portion of the back film to expose the under-display camera area of ​​the display panel through the through-hole in the first back film portion of the back film.

13. A display panel, characterized in that, The display panel is manufactured using the method described in claim 12.

14. A display device, characterized in that, include: The display panel and camera as described in claim 13, wherein the camera corresponds to the through hole in the back film and the under-display camera area of ​​the display panel.

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