DISPLAY PLATFORMS, DISPLAY PLATFORM MANUFACTURING METHODS, AND DISPLAY DEVICES

Abstract

The invention relates to a display substrate, a method for constructing a display substrate, and a display device. The display substrate consists of a rigid substrate, as well as a flexible film and a display functional layer which are continuously stacked on the rigid substrate. The rigid substrate has an opening at the flexural region to expose the flexible film located at the flexural region. The display substrate also includes a primary photoabsorber which is located within the display region and on one side of the display region near the flexural region. The primary photoabsorber is located on one side of the rigid substrate facing away from the flexible film or between the rigid substrate and the flexible film. According to the invention, because the primary photoabsorber is positioned on one side of the display region near the flexural region, laser light is used by laser lifting without alignment with high precision, and even if a portion of the laser light energy exceeds the flexural region, this energy will be absorbed by the primary photoabsorber, thereby preventing the rigid substrate of the display region from separating from the flexible film.

Description

Display substrate, preparation method thereof, and display device Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display substrate, a preparation method thereof, and a display device. Background Art

[0002] Micro / Mini-LED (Micro / Mini-LED) display technology, as a next-generation display technology, offers advantages such as high brightness, excellent luminous efficiency, and low power consumption. Micro / Mini-LED chips are typically transferred to display substrates through transfer printing. However, due to limitations in transfer printing technology, large-scale LED display substrates cannot be directly produced. Therefore, multiple small-scale LED display substrates are typically spliced ​​together to form a large-scale LED display substrate.

[0003] Small-sized LED display substrates generally include a display area and a bonding area. The display area is used for display, and the bonding area is used to bond with a flexible circuit board so that external signals can be written to the display substrate through the flexible circuit board. In related art, a bending area is also provided between the display area and the bonding area on the small-sized LED display substrate, so that the bonding area can be partially bent to the back of the display substrate. When splicing, the spacing between the display areas in adjacent small-sized LED display substrates can be greatly reduced, thereby reducing the splicing gap. However, the existing LED display substrates are not easy to bend due to the complex film layer structure and thick thickness in the bending area.

[0004] Summary of the Invention

[0005] In view of this, the embodiments of the present application provide a display substrate, a method for preparing the same, and a display device. The specific solutions are as follows:

[0006] In a first aspect, an embodiment of the present application provides a display substrate, wherein the display substrate comprises: a display area, a bending area, and a binding area, the display substrate being bent along the bending area so that the bending area is folded on the backlight side of the display area of ​​the display substrate; the display substrate comprises: a rigid substrate, a flexible film layer and a display function layer sequentially stacked on the rigid substrate;

[0007] The rigid substrate has an opening in the bending area to expose the flexible film layer in the bending area;

[0008] The display substrate further includes: a first light absorbing portion located in the display area and located on a side of the display area close to the bending area;

[0009] The first light absorbing portion is located on a side of the rigid substrate facing away from the flexible film layer or on a side of the rigid substrate facing the flexible film layer.

[0010] Optionally, in the present application, it further includes: a second light absorbing portion located in the binding area and located on a side of the binding area close to the bending area;

[0011] The second light absorbing portion is located on a side of the rigid substrate facing away from the flexible film layer or on a side of the rigid substrate facing the flexible film layer.

[0012] Optionally, in the present application, the material of the first light absorbing part includes an inorganic material; and / or the material of the second light absorbing part includes an inorganic material.

[0013] Optionally, in the present application, there is a preset distance between a boundary of the first light absorbing portion close to the bending area and a boundary of the display area close to the bending area.

[0014] Optionally, in the present application, the width of the light absorbing layer is greater than or equal to 1 mm.

[0015] Optionally, in the present application, the inorganic material includes a semiconductor material, and the band gap Eg of the semiconductor material satisfies the following conditions:

[0016] Eg≤hkc / λ;

[0017] λ is the wavelength of the laser used when the opening is formed by the laser lift-off technology, h is the Planck constant, k is a constant, and c is the speed of light.

[0018] Optionally, in the present application, the semiconductor material includes a metal oxide semiconductor or a silicon semiconductor.

[0019] Optionally, in the present application, the silicon semiconductor includes polycrystalline silicon or single crystal silicon.

[0020] Optionally, in the present application, the thickness of the first light absorbing portion is 300 angstroms to 3000 angstroms;

[0021] The thickness of the second light absorbing portion is 300 angstroms to 3000 angstroms.

[0022] Optionally, in the present application, the first light absorbing portion and the second light absorbing portion are configured to be in the same layer and made of the same material.

[0023] Optionally, in the present application, the first light absorbing portion and the second light absorbing portion are both arranged on a side of the rigid substrate facing the flexible film layer.

[0024] Optionally, in the present application, the rigid substrate includes a first sub-rigid substrate and a second sub-rigid substrate, wherein the first sub-rigid substrate is located in the display area, and the second sub-rigid substrate is located in the binding area; the display substrate further includes:

[0025] A first buffer glue covers the side wall of the first sub-rigid substrate facing the opening.

[0026] Optionally, in the present application, the display substrate further includes:

[0027] A second buffer glue covers the side wall of the second sub-rigid substrate facing the opening.

[0028] Optionally, in the present application, the display function layer includes:

[0029] a buffer layer located on a side of the flexible film layer away from the rigid substrate;

[0030] a plurality of first traces located on a side of the buffer layer away from the flexible membrane layer;

[0031] a first insulating layer located on a side of the first trace away from the flexible membrane layer;

[0032] a plurality of second traces located on a side of the first insulating layer away from the flexible membrane layer, each of the first traces being connected to at least one of the second traces via a first via hole penetrating the first insulating layer;

[0033] a second insulating layer located on a side of the second trace away from the flexible film layer;

[0034] The light emitting diode is located on a side of the second insulating layer away from the flexible film layer, and is connected to the second trace through a second via hole penetrating the second insulating layer.

[0035] In a second aspect, the present application further provides a display device comprising a plurality of display substrates provided by embodiments of the present application spliced ​​together.

[0036] In a third aspect, the present application further provides a method for preparing a display substrate, wherein the display substrate comprises: a display area, a bending area, and a binding area, wherein the bending area is located between the display area and the binding area; the preparation method comprises:

[0037] forming a flexible film layer on the first surface of the rigid substrate;

[0038] forming a display function layer on a side of the flexible film layer away from the rigid substrate;

[0039] From one side of the second surface of the rigid substrate, removing the rigid substrate in the bending area by a laser lift-off process;

[0040] bending the display substrate at the bending area so that the display function layer in the binding area and the display function layer in the display area are located on different surfaces of the display substrate;

[0041] The preparation method further comprises: before forming the flexible film layer on the first surface of the rigid substrate, forming a first light absorbing portion on the first surface of the rigid substrate;

[0042] Alternatively, before forming the flexible film layer on the first surface of the rigid substrate, forming a first light absorbing portion on the second surface of the rigid substrate;

[0043] Alternatively, after forming the display function layer and before removing the rigid substrate in the bending area by a laser lift-off process, a first light absorbing portion is formed on the second surface of the rigid substrate;

[0044] The first light absorbing portion is located in the display area and on a side of the display area close to the bending area. The first light absorbing portion is used to absorb light in a wavelength band including the laser.

[0045] In one possible implementation, the preparation method further includes:

[0046] The preparation method further includes: before forming the flexible film layer on the first surface of the rigid substrate, forming a second light absorbing portion on the first surface of the rigid substrate;

[0047] Alternatively, before forming the flexible film layer on the first surface of the rigid substrate, forming a second light absorbing portion on the second surface of the rigid substrate;

[0048] Alternatively, after forming the display function layer and before removing the rigid substrate in the bending area by a laser lift-off process, a second light absorbing portion is formed on the second surface of the rigid substrate;

[0049] The second light absorbing portion is located in the binding area and on a side of the binding area close to the bending area. The second light absorbing portion is used to absorb light in a wavelength band including the laser.

[0050] In a possible implementation manner, the first light absorbing portion and the second light absorbing portion are formed simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG1 is a schematic structural diagram of a display substrate in the related art;

[0052] FIG2 is a schematic structural diagram of a display substrate in the related art showing display abnormality;

[0053] FIG3 is a schematic diagram of a structure of a display substrate before being bent according to an embodiment of the present application;

[0054] FIG4 is a schematic diagram of another structure of a display substrate before being bent according to an embodiment of the present application;

[0055] FIG5 is a schematic diagram of laser lift-off of a display substrate according to an embodiment of the present application;

[0056] FIG6 is a schematic diagram of another structure of a display substrate before being bent according to an embodiment of the present application;

[0057] FIG7 is a schematic diagram of another structure of a display substrate before being bent according to an embodiment of the present application;

[0058] FIG8 is a schematic diagram of a partial structure of a display substrate provided in an embodiment of the present application;

[0059] FIG9 is a schematic diagram of a partial structure of a display substrate provided in an embodiment of the present application;

[0060] FIG10 is a schematic diagram of a structure of a display substrate after being bent according to an embodiment of the present application;

[0061] FIG11 is a schematic diagram of another structure of a display substrate after being bent according to an embodiment of the present application;

[0062] FIG12 is a schematic diagram of another structure of a display substrate before being bent according to an embodiment of the present application;

[0063] FIG13 is a schematic diagram of another structure of a display substrate after being bent according to an embodiment of the present application;

[0064] FIG14 is a schematic flow chart of a method for preparing a display substrate according to an embodiment of the present application;

[0065] FIG15 is a schematic flow chart of another method for preparing a display substrate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0066] In the related technical solution, when making a display substrate for splicing, it is necessary to remove the rigid substrate in the bending area of ​​the display substrate so as to bend the area outside the display area to the back of the display substrate. When removing the rigid substrate in the bending area, LLO (laser lift-off) is first performed to destroy the chemical bond between the rigid substrate and the flexible substrate by laser, so that the rigid substrate in the bending area is separated from the flexible substrate, and then the rigid substrate is cut to remove the rigid substrate in the bending area. Since general LLO equipment does not have a precise alignment function, the peeling position is uncontrollable in the actual process. In order to ensure that the rigid substrate in the bending area can be completely peeled off, the laser action area can only be expanded, so that the laser action area will exceed the bending area. As shown in Figure 1, S1 is the bending zone. The rigid substrate 1' and flexible substrate 2' in S1 need to be separated using LLO technology. However, due to the poor precision of the laser, the flexible substrate 2' in S2 will also separate from the rigid substrate 1'. As can be seen in Figure 1, the area of ​​S2 is larger than that of S1. That is, the flexible substrate 2' at the junction of the display area and the bending zone, and at the junction of the binding area and the bending zone, will separate from the rigid substrate 1'. As shown in Figure 2, when the display substrate is bent in the bending zone, the buffer glue between the rigid substrate 1' and the flexible substrate 2' in S3 will overflow, resulting in a significant height difference between this area and the rest of the display area. This will increase the height of S3 by 70-80μm, affecting the appearance of the display substrate and the wide-viewing angle display effect.

[0067] In order to solve the above problems, embodiments of the present application provide a display substrate, a preparation method thereof, and a display device, which can avoid display anomalies.

[0068] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments set forth herein; on the contrary, these embodiments are provided to make the present application more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and their repeated descriptions will be omitted. The words expressing position and direction described in this application are all explained using the accompanying drawings as examples, but changes can be made as needed, and all changes are included in the scope of protection of this application. The drawings in this application are only used to illustrate relative position relationships and do not represent true proportions.

[0069] It should be noted that specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in a variety of ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application and is not intended to limit the scope of the present application. The scope of protection of the present application shall be determined by the appended claims.

[0070] The display substrate, its preparation method and display device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0071] Referring to Figures 3 and 4, Figures 3 and 4 are schematic diagrams of the structure of a display substrate provided in an embodiment of the present application. The display substrate provided in an embodiment of the present application includes: a display area A1, a bending area A2, and a binding area A3, wherein the bending area A2 is located between the display area A1 and the binding area A3; the display substrate is bent along the bending area A2, so that the bending area A2 is folded onto the backlight side of the display area A1 of the display substrate. Figures 3 and 4 are schematic diagrams of the structure of the display substrate before it is bent.

[0072] Continuing with Figures 3 and 4 , the display substrate comprises a rigid substrate 1, a flexible film layer 2, and a display function layer 3, sequentially stacked on the rigid substrate. Rigid substrate 1 has an opening 10 formed using a laser lift-off process in bending region A2, exposing the flexible film layer 22 located in bending region A2. Rigid substrate 1 can be a glass substrate or a quartz substrate. The flexible film layer 2 can be made of polyimide with a thickness not exceeding 6 μm, which improves its bending properties.

[0073] The display substrate may further include: a first light absorbing portion 41 located within the display area A1 and located on the side of the display area A1 close to the bending area A2; as shown in FIG3 , the first light absorbing portion 41 may be located on the side of the rigid substrate 1 facing away from the flexible film layer 2; or, as shown in FIG4 , the first light absorbing portion 41 may be located on the side of the rigid substrate 1 facing the flexible film layer 2.

[0074] In the display substrate provided in the embodiment of the present application, the opening 10 of the rigid substrate 1 is formed using a laser lift-off process. Referring to FIG5 , when the rigid substrate 1 and the flexible film layer 2 are lift-offed using an LLO device, the laser action area is larger than the bending area A2 to ensure that the rigid substrate 1 in the bending area A2 can be completely lift-offed. The rigid substrate 1 in the bending area A2 is then cut to form the opening. In the present application, a first light absorbing portion 41 is provided on the side of the display area A1 near the bending area A2. The first light absorbing portion 41 can absorb the laser acting on the display area A1, thereby preventing the rigid substrate 1 in the display area A1 from separating from the flexible film layer 2.

[0075] In the embodiment of the present application, since the first light absorbing portion is provided, the laser used for LLO does not need to be aligned with high precision. Even if part of the laser energy exceeds the bending zone, it will be absorbed by the first light absorbing portion.

[0076] It should be noted that in this application, due to the diffraction phenomenon, there will be a peeling zone of about 10μm at the boundary of the first light absorbing part near the bending zone. Of course, when the wavelength of ultraviolet light is different, the boundary deviation caused by this diffraction will be slightly different. Specifically, combined with the boundary alignment accuracy of the first light absorbing part (±20μm), theoretically, the maximum deviation of the peeling zone from the bending zone does not exceed 20μm.

[0077] During implementation, the line width of the first light absorber needs to be set to be larger than the alignment accuracy of the LLO device, taking into account the alignment accuracy of the LLO device. Since conventional LLOs do not have an alignment function and only have a mechanical positioning accuracy of ~1mm during placement, the line width of the first light absorber can be larger than 1mm. The first light absorber is located at the junction of the display area and the bending area, and the edge of the first light absorber can overlap with the edge of the bending area.

[0078] In the present application, since the first light absorbing portion is located on the backlight side of the display functional layer and will not affect the display, the first light absorbing portion can be arranged to cover the display area.

[0079] In this application, to achieve the bending of the display substrate, the flexible film layer can be located only in the bending area. Of course, the flexible film layer can also be provided as an entire layer, that is, the flexible film layer covers the rigid substrate and the opening of the rigid substrate, without limitation. The following embodiments of this application are described using the entire flexible film layer as an example.

[0080] In specific implementation, when film layers are formed on both sides of the rigid substrate, the rigid substrate needs to be flipped during preparation, which increases the difficulty of the process. Therefore, in this application, the first light absorbing portion is preferably located between the rigid substrate and the flexible film layer.

[0081] For example, the material of the first light absorbing portion in this application may include either an inorganic material or an organic material. When the material of the first light absorbing portion is an organic material, the organic material may harden when strongly absorbing light during laser lift-off. Furthermore, a decomposition reaction may occur, causing the first light absorbing portion to overflow toward the bending region, thereby affecting the boundary definition accuracy of the first light absorbing portion. Therefore, this application preferably uses an inorganic material as the material of the first light absorbing portion.

[0082] In a specific implementation, the wavelength of the laser used in the laser lift-off process may be 280-308 nm, and the material of the first light absorbing portion may be an inorganic material that can absorb the laser in this wavelength range.

[0083] Optionally, in the present application, the material of the first light absorbing portion may include a semiconductor material, and the band gap Eg of the semiconductor material satisfies the following conditions:

[0084] Eg≤hkc / λ;

[0085] λ is the wavelength of the laser used to form the opening of the rigid substrate using the laser lift-off technology, and h is the Planck constant, which is 6.626*10 -34 J·s, k is a constant, its value is 1.6*10 -19 J / eV, c is the speed of light, and its value is 3*10 8 m / s=3*10 17 nm / s.

[0086] Therefore, in this application, the bandgap width Eg of the semiconductor material must meet the following requirements: Eg ≤ 1240 / λeV. Semiconductor materials within this bandgap width can absorb laser light through their own electron excitation transitions. For example, for a laser wavelength of λ = 308nm, the bandgap width Eg of the semiconductor material is ≤ 4.02eV.

[0087] Illustratively, in the present application, the semiconductor material may include a metal oxide semiconductor or a silicon semiconductor.

[0088] For example, metal oxide semiconductors satisfying Eg≤4.02eV may include zinc oxide (ZnO), titanium oxide (TiO2), copper oxide (CuO), iron oxide (Fe2O3), indium oxide (In2O3) or vanadium oxide (V2O5), etc., which are not limited here.

[0089] In a specific implementation, since the band gap Eg of polycrystalline silicon (p-Si) and single crystal silicon (a-Si) is ≤ 2 eV, in this application, the silicon semiconductor may include polycrystalline silicon (p-Si) or single crystal silicon (a-Si).

[0090] In addition, when the material of the first light absorbing portion is p-Si or a-Si, p-Si or a-Si is a commonly used material in the display field, so it can be formed using existing equipment during preparation. In specific implementation, using existing equipment and processes, the thickness of the p-Si or a-Si film can reach Therefore, in this application, the thickness of the first light absorbing portion can be controlled to be Between, for example etc., not limited here.

[0091] Furthermore, in the present application, the binding area is close to the bending area. Since the laser action area exceeds the binding area, the rigid substrate and the flexible film layer may also peel off in the binding area, which will subsequently reduce the mechanical rigidity of the binding area. Therefore, in the present application, as shown in Figures 6 and 7, the display substrate further includes: a second light absorbing portion 42 located in the display area A1 and located on the side of the binding area close to the bending area A2. The second light absorbing portion 42 is used to absorb light in the wavelength band including the laser;

[0092] As shown in Figure 6, the second light absorbing portion is located on the side of the rigid substrate 1 away from the flexible film layer 2, or, as shown in Figure 7, the second light absorbing portion is located between the rigid substrate 1 and the flexible film layer 2. This can prevent the rigid substrate 1 and the flexible film layer 2 from peeling off in the bending area.

[0093] It should be noted that in this application, due to the diffraction phenomenon, there will be a peeling zone of about 10μm at the boundary of the second light absorbing portion near the bending zone. Of course, when the wavelength of ultraviolet light is different, the boundary deviation caused by this diffraction will be slightly different. Specifically, combined with the boundary alignment accuracy of the second light absorbing portion (±20μm), theoretically, the maximum deviation of the peeling zone from the bending zone does not exceed 20μm.

[0094] During implementation, the line width of the second light absorbing portion needs to be set to be greater than the alignment accuracy of the LLO device, taking into account the alignment accuracy of the LLO device. Since conventional LLOs do not have an alignment function and only have a mechanical position accuracy of ±1mm during placement, the line width of the second light absorbing portion can be greater than 1mm. The second light absorbing portion is located at the junction of the binding area and the bending area, and the edge of the second light absorbing portion can overlap with the edge of the bending area.

[0095] In the present application, since the second light absorbing portion is located on the backlight side of the display functional layer and will not affect the display, the second light absorbing portion can be arranged to cover the display area.

[0096] In specific implementation, when film layers are formed on both sides of the rigid substrate, the rigid substrate needs to be flipped during preparation, which increases the process difficulty. Therefore, in this application, the second light absorbing portion is preferably located between the rigid substrate and the flexible film layer.

[0097] For example, the material of the second light absorbing portion in this application may include either an inorganic material or an organic material. When the material of the second light absorbing portion is an organic material, the organic material may harden when strongly absorbing light during laser lift-off. On the other hand, a decomposition reaction may occur, causing the second light absorbing portion to overflow toward the bending region, thereby affecting the boundary definition accuracy of the second light absorbing portion. Therefore, this application preferably uses an inorganic material as the material of the first light absorbing portion.

[0098] In a specific implementation, the wavelength of the laser used in the laser lift-off process may be 280-308 nm, and the material of the second light absorbing portion may be an inorganic material that can absorb the laser in this wavelength range.

[0099] Optionally, in the present application, the material of the second light absorbing portion may include a semiconductor material, and the band gap Eg of the semiconductor material satisfies the following conditions:

[0100] Eg≤hkc / λ;

[0101] λ is the wavelength of the laser, and h is the Planck constant, which is 6.626*10 -34 J·s, k is a constant, its value is 1.6*10 -19 J / eV, c is the speed of light, and its value is 3*10 8 m / s=3*10 17 nm / s.

[0102] Illustratively, in the present application, the semiconductor material may include a metal oxide semiconductor or a silicon semiconductor.

[0103] For example, metal oxide semiconductors satisfying Eg≤4.02eV may include zinc oxide (ZnO), titanium oxide (TiO2), copper oxide (CuO), iron oxide (Fe2O3), indium oxide (In2O3) or vanadium oxide (V2O5), etc., which are not limited here.

[0104] In a specific implementation, since the band gap width Eg of polycrystalline silicon (p-Si) and single crystal silicon (a-Si) is ≤ 2eV, in this application, the silicon semiconductor may include polycrystalline silicon (p-Si) or single crystal silicon (a-Si).

[0105] In addition, when the material of the second light absorbing portion is p-Si or a-Si, p-Si or a-Si is a commonly used material in the display field, so it can be formed by using the following equipment during preparation. In specific implementation, using existing equipment and process, the thickness of the p-Si or a-Si film can reach Therefore, in this application, the thickness of the second light absorbing portion can be controlled to Between, for example etc., not limited here.

[0106] To simplify the process, the first light absorbing portion and the second light absorbing portion are provided in the same layer and the same material, so that the patterns of the first light absorbing portion and the second light absorbing portion can be formed simultaneously using a single patterning process, thereby reducing costs.

[0107] As shown in Figure 8 , the rigid substrate 1 includes a first sub-rigid substrate 1a and a second sub-rigid substrate 1b. The first sub-rigid substrate 1a is located in the display area A1, and the second sub-rigid substrate 1b is located in the binding area A3. The display substrate also includes a first adhesive 11 covering the sidewall of the first sub-rigid substrate 1a facing the opening. The adhesive buffer 11 prevents the flexible film layer 2 from bending at excessive angles, which could lead to fracture.

[0108] Furthermore, the display substrate of the present application further includes: a second buffer glue covering the side wall of the second sub-rigid substrate facing the opening.

[0109] In the present application, when the buffer glue 11 is set at the opening 10 of the rigid substrate 1, the position of the buffer glue 11 is at the position shown by the circle, and then as the bending process proceeds, the buffer glue 11 slowly overflows until it wraps the backlight side of the rigid substrate 1. If the first light absorption portion 41 located on the side of the rigid substrate 1 away from the flexible film layer 2 is too thick, it will prevent the buffer glue 11 from flowing to the bottom side of the rigid substrate 1, causing the buffer glue 11 to be blocked and unable to remain after bending.

[0110] Therefore, optionally, in the present application, both the first light absorbing portion 41 and the second light absorbing portion 42 are located between the flexible film layer 2 and the rigid substrate 1. Alternatively, when both the first light absorbing portion 41 and the second light absorbing portion 42 are located on the rigid substrate 1 away from the flexible film layer 2, the thickness of the first light absorbing portion 41 and the second light absorbing portion 42 should not be too thick.

[0111] Furthermore, in the present application, in order to effectively protect the buffer glue at the corners of the bending zone, the buffer glue can overflow into the display area. This requires that the peeling area of ​​the rigid substrate and the flexible film layer can extend into the display area. This requires that the first light absorbing part be retracted into the display area by a preset distance, that is, there is a preset distance between the boundary of the first light absorbing part close to the bending zone and the boundary of the display area close to the bending zone.

[0112] Considering the alignment accuracy of the first light absorber's boundary (±20μm), the theoretical maximum deviation of the peeling zone from the bending zone is no more than 20μm. Taking into account the diffraction effect at the boundary of the first light absorber, the distance the first light absorber retracts into the display area is less than 20μm. Referring to Figure 9 , for example, if the diffraction effect at the boundary of the first ultraviolet light absorber 41 can result in a 10μm peeling zone, then the distance S1 of the first light absorber 41 retracted into the display area A1 can be set to 10μm.

[0113] Specifically, in the present application, after the display substrate is bent, referring to Figures 10 and 11, when the display substrate is bent, the display function layer 3 of the display area A1 and the display function layer 3 of the binding area A3 are respectively located on different surfaces of the display substrate, the display function layer 3 of the display area A1 is located on the light-emitting side of the display substrate, and the display function layer 3 of the binding area A3 is located on the backlight side of the display substrate.

[0114] In a specific implementation, in this application, referring to FIG12 , the display function layer may include:

[0115] The buffer layer 31 is located on the side of the flexible film layer 2 away from the rigid substrate 1 . The buffer layer 31 may be made of one or more insulating materials selected from silicon nitride, silicon oxide, and silicon oxynitride.

[0116] The plurality of first traces 32 are located on a side of the buffer layer 31 away from the flexible film layer 2 . The first traces 32 may be made of Cu with a thickness of 0.6-1.8 μm.

[0117] The first insulating layer 33, located on the side of the first trace 32 away from the flexible film layer 2, may include a first planarizing layer. The first planarizing layer may be made of a thick organic insulating material, such as an organic resin, to fill the gaps between the first traces 7, providing a smooth surface for subsequent processing and preventing large step differences. This prevents LED displacement during LED bonding. The thickness of the first planarizing layer should be greater than or equal to the thickness of the first trace, and may range from 2 to 3.5 μm. In addition to the first planarizing layer, the first insulating layer may also include an inorganic insulating layer. The inorganic insulating layer may be made of an inorganic insulating material, such as silicon nitride, silicon oxide, or silicon oxynitride, to protect the first trace from oxidation during subsequent high-temperature processing. The thickness of the inorganic insulating layer may range from 500 to 3000 angstroms.

[0118] Multiple second traces 34 are located on the side of the first insulating layer 33 away from the flexible film layer 2. Each first trace 32 is connected to at least one second trace 34 via a first via hole penetrating the first insulating layer 33. The second trace 34 can be made of Cu with a thickness of 0.6-1.2 μm.

[0119] A second insulating layer is located on the side of the second trace 34 away from the flexible film layer 2. The second insulating layer may include a passivation layer 35 and a second planarization layer 36. Passivation layer 35 may be made of an inorganic insulating material such as silicon nitride, silicon oxide, or silicon oxynitride to protect the second trace from oxidation during subsequent high-temperature processes. The thickness of passivation layer 35 may be 500-3000 angstroms. Second planarization layer 36 may be made of a thicker organic insulating material, such as an organic resin, to fill the gaps between the second traces, providing a smooth surface for subsequent processing and preventing large step differences. This prevents LED displacement during LED bonding. The thickness of second planarization layer 36 should be greater than or equal to the thickness of the second trace.

[0120] A light-emitting diode (LED) 38 is located on a side of the second insulating layer away from the flexible film layer 2. LED 38 is connected to the second trace 34 via a second via hole penetrating the second insulating layer. Specifically, LED 38 can be formed on the display substrate through processes such as solder printing, die bonding, reflow soldering, and packaging. LED 38 includes an N pad and a P pad. The N pad and P pad of the LED are each connected to the second trace 34 at different locations via a second via hole penetrating the second planar layer 36 and the passivation layer 35.

[0121] In a specific implementation, as shown in FIG12 , in order to protect the exposed second traces 34 from being oxidized, a conductive protection layer 37 may be formed on the second traces 34 . The conductive protection layer 37 may be made of ITO.

[0122] In specific implementation, the boundary between the bending area A2 and the display area A1 in the display substrate is generally defined by the boundary of the second bit line. As shown in Figure 12, the boundary B of the second bit line 34 is the boundary of the display area A1, wherein point A is the left boundary of the second trace 34 directly above the first light absorption portion 41, point B is the right boundary of the second trace 34 directly above the first light absorption portion 41, and point C is the boundary of the outer contour of the LED chip close to the bending area.

[0123] In a specific implementation, as shown in FIG13 , a flexible circuit board 5 is also bound to the binding area A3 .

[0124] Based on the same inventive concept, the present application also provides a method for preparing any of the above-mentioned display substrates, wherein the display substrate comprises: a display area, a bending area and a binding area, and the bending area is located between the display area and the binding area.

[0125] As shown in FIG14 , the preparation method includes:

[0126] S101, forming a first light absorbing portion on the first surface of the rigid substrate, wherein the first light absorbing portion is located in the display area and on a side of the display area close to the bending area;

[0127] S102, forming a flexible film layer on the first surface of the rigid substrate;

[0128] S103, forming a display function layer on a side of the flexible film layer away from the rigid substrate;

[0129] S104, removing the rigid substrate in the bending area from one side of the second surface of the rigid substrate using a laser lift-off process;

[0130] S105 , bending the display substrate at the bending area so that the display function layer in the binding area and the display function layer in the display area are located on different surfaces of the display substrate.

[0131] Alternatively, as shown in FIG15 , the preparation method includes:

[0132] S201, forming a flexible film layer on a first surface of a rigid substrate;

[0133] S202, forming a display function layer on a side of the flexible film layer away from the rigid substrate;

[0134] S203, forming a first light absorbing portion on the second surface of the rigid substrate, wherein the first light absorbing portion is located in the display area and on a side of the display area close to the bending area;

[0135] S204, removing the rigid substrate in the bending area from one side of the second surface of the rigid substrate using a laser lift-off process;

[0136] S205 , bending the display substrate at the bending area so that the display function layer in the binding area and the display function layer in the display area are located on different surfaces of the display substrate.

[0137] In the preparation method provided in the embodiments of the present application, the rigid substrate in the bend region is removed using a laser lift-off process during formation. When using an LLO device to lift the rigid substrate and flexible film layer, the laser action area is larger than the bend region to ensure that the rigid substrate in the bend region can be completely lifted off. The rigid substrate 1 in the bend region is then cut to form an opening. In this application, a first light absorbing portion is provided on the side of the display region near the bend region A2. This first light absorbing portion can absorb the laser light acting on the display region, thereby preventing separation of the rigid substrate and flexible film layer in the display region.

[0138] In a feasible embodiment, the preparation method further includes: before forming the flexible film layer on the first surface of the rigid substrate, forming a second light absorbing portion on the first surface of the rigid substrate; wherein the second light absorbing portion is located in the binding area and is located on the side of the binding area close to the bending area, and the second light absorbing portion is used to absorb light in a wavelength band including laser.

[0139] Alternatively, in a feasible embodiment, the preparation method further includes: after forming the display function layer, before using a laser lift-off process to remove the rigid substrate in the bending area, forming a second light absorbing portion on the second surface of the rigid substrate; wherein the second light absorbing portion is located in the binding area, and is located on the side of the binding area close to the bending area, and the second light absorbing portion is used to absorb light in a wavelength band including laser.

[0140] In order to simplify the process and reduce costs, in the preparation method of the present application, the first light absorbing portion and the second light absorbing portion are formed simultaneously.

[0141] Based on the same inventive concept, the present application also provides a display device, comprising a plurality of LED display substrates of any one of the above-mentioned types provided in the embodiments of the present application, which are spliced ​​together.

[0142] The display device includes but is not limited to components such as a radio frequency unit, a network module, an audio output unit, an input unit, a sensor, a display unit, a user input unit, an interface unit, a memory, a processor, and a power supply. Those skilled in the art will understand that the structure of the above-mentioned display device does not constitute a limitation on the display device, and the display device may include more or fewer of the above-mentioned components, or a combination of certain components, or different component arrangements. In the embodiments of the present application, the display device includes but is not limited to a display, a mobile phone, a tablet computer, a television, a wearable electronic device, a navigation display device, etc. The implementation of the display device can refer to the embodiments of the above-mentioned display substrate, and the repeated parts will not be repeated.

[0143] The display device can be any product or component with a display function, such as a television, a monitor, a digital photo frame, a mobile phone, a tablet computer, etc., wherein the display device also includes a flexible circuit board, a printed circuit board and a backplane.

[0144] It should be noted that the various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences from other embodiments. In particular, since the embodiments are generally similar to the product embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the product embodiments.

[0145] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0146] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “under” another element, it can be “directly on” or “under” the other element or intervening elements may be present.

[0147] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0148] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A display substrate, wherein, the display substrate includes a display area, a bending area, and a bonding area, and the display substrate is bent along the bending area so that the bending area is folded on the backlight side of the display area of the display substrate; the display substrate includes a rigid substrate, a flexible film layer, and a display functional layer that are sequentially stacked on the rigid substrate; the rigid substrate has an opening in the bending area to expose the flexible film layer located in the bending area; the display substrate further includes a first light absorption portion located in the display area and on the side of the display area close to the bending area; the first light absorption portion is located on the side of the rigid substrate facing away from the flexible film layer or on the side of the rigid substrate facing the flexible film layer.

2. The display substrate according to claim 1, wherein, it further includes: a second light absorption portion located in the bonding area and on the side of the bonding area close to the bending area; the second light absorption portion is located on the side of the rigid substrate facing away from the flexible film layer or on the side of the rigid substrate facing the flexible film layer.

3. The display substrate according to claim 2, wherein, the material of the first light absorption portion includes an inorganic material; and / or the material of the second light absorption portion includes an inorganic material.

4. The display substrate according to any one of claims 1-3, wherein, there is a preset distance between the boundary of the first light absorption portion on the side close to the bending area and the boundary of the display area on the side close to the bending area.

5. The display substrate according to any one of claims 1-3, wherein, the width of the light absorption layer is greater than or equal to 1 mm.

6. The display substrate according to claim 3, wherein, the inorganic material includes a semiconductor material, and the band gap Eg of the semiconductor material satisfies the following conditions: Eg ≤ hkc / λ; λ is the wavelength of the laser used when forming the opening by laser lift-off technology, h is Planck's constant, k is a constant, and c is the speed of light.

7. The display substrate according to claim 6, wherein, the semiconductor material includes a metal oxide semiconductor or a silicon semiconductor.

8. The display substrate according to claim 7, wherein, the silicon semiconductor includes polysilicon or monocrystalline silicon.

9. The display substrate according to claim 8, wherein, the thickness of the first light absorption portion is 300 Å to 3000 Å; the thickness of the second light absorption portion is 300 Å to 3000 Å.

10. The display substrate according to claim 3, wherein, the first light absorption portion and the second light absorption portion are arranged to be of the same layer and the same material.

11. The display substrate according to claim 10, wherein, both the first light absorption portion and the second light absorption portion are arranged on the side of the rigid substrate facing the flexible film layer.

12. The display substrate according to any one of claims 1-3, wherein, the rigid substrate includes a first sub-rigid substrate and a second sub-rigid substrate, wherein the first sub-rigid substrate is located in the display area and the second sub-rigid substrate is located in the bonding area; the display substrate further includes: a first buffer adhesive coating the side wall of the first sub-rigid substrate facing the opening.

13. The display substrate according to claim 12, wherein, the display substrate further comprises: a second buffer adhesive coating the side wall of the second sub-rigid substrate facing the opening.

14. The display substrate according to any one of claims 1-3, wherein, the display functional layer comprises: a buffer layer located on a side of the flexible film layer away from the rigid substrate; a plurality of first traces located on a side of the buffer layer away from the flexible film layer; a first insulating layer located on a side of the first traces away from the flexible film layer; a plurality of second traces located on a side of the first insulating layer away from the flexible film layer, each of the first traces being connected to at least one of the second traces through a first via hole penetrating the first insulating layer; a second insulating layer located on a side of the second traces away from the flexible film layer; a light-emitting diode located on a side of the second insulating layer away from the flexible film layer, the light-emitting diode being connected to the second traces through a second via hole penetrating the second insulating layer.

15. A display device, wherein, it includes a plurality of display substrates according to any one of claims 1-14 spliced together.

16. A method for manufacturing a display substrate, wherein, the display substrate includes a display area, a bending area, and a bonding area, and the bending area is located between the display area and the bonding area; the manufacturing method includes: forming a flexible film layer on a first surface of the rigid substrate; forming a display functional layer on a side of the flexible film layer away from the rigid substrate; removing the rigid substrate in the bending area from a side of the second surface of the rigid substrate by using a laser lift-off process; bending the display substrate in the bending area so that the display functional layer in the bonding area and the display functional layer in the display area are located on different surfaces of the display substrate; the manufacturing method further includes: forming a first light absorption part on the first surface of the rigid substrate before forming the flexible film layer on the first surface of the rigid substrate; or, forming a first light absorption part on the second surface of the rigid substrate before forming the flexible film layer on the first surface of the rigid substrate; or, forming a first light absorption part on the second surface of the rigid substrate after forming the display functional layer and before removing the rigid substrate in the bending area by using the laser lift-off process; the first light absorption part is located in the display area and on a side of the display area close to the bending area, and the first light absorption part is used for absorbing light in a band including the laser.

17. The manufacturing method according to claim 16, wherein, the manufacturing method further includes: the manufacturing method further includes: forming a second light absorption part on the first surface of the rigid substrate before forming the flexible film layer on the first surface of the rigid substrate; or, forming a second light absorption part on the second surface of the rigid substrate before forming the flexible film layer on the first surface of the rigid substrate; or, forming a second light absorption part on the second surface of the rigid substrate after forming the display functional layer and before removing the rigid substrate in the bending area by using the laser lift-off process; The second light absorption part is located within the bonding area and on a side of the bonding area close to the bending area, and the second light absorption part is configured to absorb light in a wavelength band including the laser light.

18. The manufacturing method according to claim 17, wherein, the first light absorption part and the second light absorption part are formed simultaneously.

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