Display substrate, preparation method thereof and display device

Abstract

A display substrate, a manufacturing method thereof, and a display device. The display substrate includes a base structure layer; the base structure layer includes a base material layer, a sacrificial layer, and an optical film layer located between the base material layer and the sacrificial layer, which are stacked; and a reflectivity of the optical film layer is greater than a transmittance of the optical film layer.

Description

Technical Field

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

[0002] Flexible materials such as PI (polyimide) substrates are widely used in high-end OLED (Organic Light-Emitting Diode) and Mini-LED display products. During manufacturing, the PI substrate needs to be produced in conjunction with a rigid substrate. A lift-off process, such as LLO (Laser Lift Off), is used to peel off the PI substrate, which carries the driving circuitry and display chip, from the surface of the rigid substrate for subsequent assembly. As users demand increasingly stringent thickness requirements for the overall device, the required thickness of the PI substrate has decreased from 100 micrometers to 50 micrometers, or even less. 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] This disclosure provides a display substrate. The display substrate includes a substrate structure layer; the substrate structure layer includes a substrate material layer, a sacrificial layer, and an optical film layer located between the substrate material layer and the sacrificial layer; the reflectivity of the optical film layer is greater than the transmittance of the optical film layer.

[0005] In an exemplary embodiment, the optical film layer includes at least one first dielectric layer and at least one second dielectric layer, wherein the refractive index of the first dielectric layer is less than the refractive index of the second dielectric layer; the first dielectric layer and the second dielectric layer are disposed overlapping along a direction away from the sacrificial layer.

[0006] In an exemplary embodiment, the optical film layer adjacent to the substrate material layer is a first dielectric layer, and the optical film layer adjacent to the sacrificial layer is also a first dielectric layer.

[0007] In an exemplary embodiment, the optical film layer adjacent to the substrate material layer is a second dielectric layer, and the optical film layer adjacent to the sacrificial layer is also a second dielectric layer.

[0008] In one exemplary embodiment, both the first dielectric layer and the second dielectric layer are made of inorganic materials.

[0009] In an exemplary embodiment, the refractive index of the optical film layer adjacent to the substrate material layer is greater than the refractive index of the substrate material layer.

[0010] In an exemplary embodiment, the refractive index of the film layer adjacent to the sacrificial layer in the optical film layer is greater than the refractive index of the sacrificial layer.

[0011] In one exemplary embodiment, the thickness of the sacrificial layer is 2.0 micrometers to 5.0 micrometers.

[0012] In one exemplary embodiment, the material of the sacrificial layer is a photosensitive organic material or a photoresist material.

[0013] In one exemplary embodiment, the material of the sacrificial layer is the same as the material of the base material layer.

[0014] In one exemplary embodiment, the display substrate further includes a circuit structure layer disposed on the side of the substrate material layer away from the sacrificial layer.

[0015] In an exemplary embodiment, the display substrate further includes a light-emitting element disposed on the side of the circuit structure layer away from the substrate structure layer, and the light-emitting element is connected to the circuit structure layer.

[0016] In one exemplary embodiment, the light-emitting element is a micro light-emitting diode or a sub-millimeter light-emitting diode.

[0017] A display device comprising the display substrate described in any of the above embodiments.

[0018] A method for preparing a display substrate, comprising:

[0019] A sacrificial layer is formed on the carrier substrate;

[0020] An optical film layer is formed on the sacrificial layer;

[0021] A substrate material layer is formed on the optical film layer;

[0022] The sacrificial layer is irradiated from the side of the carrier substrate away from the sacrificial layer using a stripping ray, so as to cause the sacrificial layer to peel off from the carrier substrate; wherein the reflectivity of the optical film layer is greater than the transmittance of the optical film layer.

[0023] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0024] The accompanying drawings are provided to further 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.

[0025] Figure 1 This is a schematic diagram illustrating the laser lift-off technique used to display substrates in related technologies.

[0026] Figure 2 This is a schematic diagram of the structure of the display substrate according to an embodiment of the present disclosure;

[0027] Figure 3A This is a schematic diagram of the optical path of the stripped light rays in the display substrate according to an embodiment of the present disclosure;

[0028] Figure 3B This is a partially enlarged view of the stripping light path in the substrate according to an embodiment of this disclosure;

[0029] Figure 4A This is a schematic diagram of the structure of the optical film layer in the display substrate according to an embodiment of the present disclosure. Figure 1 ;

[0030] Figure 4B This is a schematic diagram of the structure of the optical film layer in the display substrate according to an embodiment of the present disclosure. Figure 2 ;

[0031] Figure 5 This is a laser reflection curve obtained by simulating an optical film layer in a substrate according to an embodiment of the present disclosure. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The implementation can be carried out in many different forms. Those skilled in the art will readily understand that the methods and content can be transformed into one or more forms without departing from the spirit and scope of this disclosure. Therefore, this disclosure should not be construed as limited to the content described in the following embodiments. Without conflict, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0033] In the accompanying drawings, the size of one or more constituent elements, the thickness of layers, or areas are sometimes exaggerated for clarity. Therefore, this disclosure is not necessarily limited to these dimensions, and the shapes and sizes of the components 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.

[0034] The ordinal numbers such as "first," "second," and "third" in this disclosure are used to avoid confusion among the constituent elements, not to limit the quantity. "Multiple" in this disclosure includes two or more quantities.

[0035] In this disclosure, for convenience, terms such as "middle," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships in conjunction with the accompanying drawings. This is solely for the purpose of facilitating the description and simplification of the specification, and does not imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this disclosure. The positional relationships of the constituent elements may be appropriately changed depending on the direction in which the constituent elements are described. Therefore, the description is not limited to the terms used in the specification and may be appropriately replaced as appropriate.

[0036] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a link; they can 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 these terms in this disclosure as appropriate.

[0037] In this disclosure, a transistor is a device that includes at least three terminals: a gate electrode, a drain electrode, and a source electrode. A transistor has a channel region between the drain electrode (drain electrode terminal, drain region, or drain) and the source electrode (source electrode terminal, source region, or source), and current can flow through the drain electrode, the channel region, and the source electrode. In this disclosure, the channel region refers to the region through which current primarily flows.

[0038] In this disclosure, the first electrode can be the drain electrode and the second electrode can be the source electrode, or vice versa. In cases where transistors with opposite polarities are used or the current direction changes during circuit operation, the functions of the "source electrode" and the "drain electrode" are sometimes interchanged. Therefore, in this disclosure, the "source electrode" and the "drain electrode" can be interchanged.

[0039] In this disclosure, "connection" includes the situation where constituent elements are connected together by a component having some electrical function. There are no particular limitations on the "component having some electrical function," as long as it enables the transmission and reception of electrical signals between the connected constituent elements. Examples of "component having some electrical function" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other components having one or more functions.

[0040] In this disclosure, "parallel" refers to a state in which two straight lines form an angle of -10° or more and less than 10°, and therefore can include a state in which the angle is -5° or more and less than 5°. Furthermore, "perpendicular" refers to a state in which two straight lines form an angle of 80° or more and less than 10°, and therefore can include a state in which the angle is 85° or more and less than 95°.

[0041] In this disclosure, the terms "film" and "layer" can be interchanged. For example, sometimes "conductive layer" can be replaced with "conductive film". Similarly, sometimes "insulating film" can be replaced with "insulating layer".

[0042] In this disclosure, “about” means a value that is not strictly limited and allows for process and measurement errors.

[0043] Figure 1 This is a schematic diagram of a laser-based lift-off process for a display substrate in a related technology. The display substrate includes a carrier substrate 10 and a flexible substrate 20 disposed on the carrier substrate 10. ， and set on flexible substrate 20 ， The circuit structure layer 301 is located on the substrate. During the process of peeling off the related technology display substrate using a laser, the laser moves away from the carrier substrate 10 and away from the flexible substrate 20. ， On one side, the flexible substrate 20 is injected through the carrier substrate 10. ， ,like Figure 1 As shown by the middle arrow, the laser causes the flexible substrate 20 ， The substrate 10 and the substrate 10 are separated.

[0044] The inventors discovered through their research that, on a flexible substrate 20 ， During the peeling process from the carrier substrate 10, the laser will remove part of the flexible substrate 20 within the relevant display substrate structure. ， Vaporization, forming pores, or flexible substrate 20 ， The overall thickness was reduced, allowing most of the laser to penetrate the flexible substrate. ， Irradiation on a flexible substrate 20 ， The circuit structure layer 301 is damaged, resulting in damage to the circuitry within it. The circuit structure layer 301 is typically used to connect to functional components, such as light-emitting elements or driver chips. Damage to the circuitry within the circuit structure layer 301 will reduce the overall display performance of the display product.

[0045] If the laser irradiation energy is reduced during the peeling process, a flexible substrate of 20 will remain. ， The problem of difficulty in separating the flexible substrate 20 from the carrier substrate 10 and low peeling efficiency exists. During the peeling process, as the flexible substrate 20... ， With the reduction in thickness, when small molecule foreign matter precipitates on the surface of the substrate 10, the flexible substrate 20...， Bubbling can easily occur, reducing the airtightness of the display substrate. This can cause the display substrate to fail the reliability evaluation test, increasing the product defect rate.

[0046] This disclosure provides a display substrate, including a substrate structure layer; the substrate structure layer includes a substrate material layer, a sacrificial layer, and an optical film layer located between the substrate material layer and the sacrificial layer; the reflectivity of the optical film layer is greater than the transmittance of the optical film layer.

[0047] The disclosed display substrate can be separated from the substrate structure layer by laser lift-off process. The display substrate is configured with an optical film layer whose reflectivity is greater than its transmittance, which reduces the proportion of lift-off light penetrating the substrate material layer. This avoids damage to the circuit structure layers within the display substrate caused by the lift-off light, improves the product yield, and reduces the overall manufacturing cost of the display product.

[0048] The technical solutions of the embodiments of this disclosure are described in detail below through examples.

[0049] Figure 2 This is a schematic diagram of the structure of the display substrate in an embodiment of this disclosure. Figure 2 As shown, two directions are defined for the purpose of illustrating the technical solution, with the first direction labeled X and the second direction labeled Z. The first and second directions intersect. In the embodiments of this disclosure, the first and second directions are perpendicular to each other. The second direction (Z) is the thickness direction of the display substrate.

[0050] In the example implementation, such as Figure 2 As shown, the display substrate of this disclosure includes a substrate structure layer. The substrate structure layer includes a substrate material layer 20, a sacrificial layer 50, and an optical film layer 40 located between the substrate material layer 20 and the sacrificial layer 50, all stacked together. The optical film layer 40 is configured to have a reflectivity greater than its transmittance. For example, the reflectivity of the optical film layer 40 can be 60% to 90%, and the transmittance can be 10% to 40%. For example, the reflectivity of the optical film layer 40 can be 70% to 80%, and the transmittance can be 20% to 30%. The optical film layer 40 can reduce the proportion of stripping light entering the substrate material layer 20, thus preventing damage to the circuit structure layer 301 and the like within the display substrate. The stripping light can be a laser or the like. The reflectivity and transmittance of the optical film layer 40 can be selected according to the needs of the display panel, as long as the reflectivity of the optical film layer 40 is greater than its transmittance.

[0051] In this embodiment of the disclosure, the technical solution is described using a laser as an example to illustrate the stripping light.

[0052] In the example embodiment, the side of the sacrificial layer 50 furthest from the optical film layer 40 is the laser peel surface. The laser peel surface is the surface of the display substrate after it has been peeled from the carrier substrate 10 by laser irradiation. The laser peel surface may have peel holes left after laser irradiation, or it may be uneven, or it may be essentially flat. Different laser peel surfaces can be obtained depending on the laser configuration. For example, the laser can be set in a point, a line, or a surface, thus forming a point light source, a line light source, or a surface light source. During the laser peeling process of the display substrate, the sacrificial layer 50 can absorb laser energy, causing partial decomposition of the sacrificial layer 50 to form the laser peel surface, thereby achieving the peeling of the display substrate from the carrier substrate 10.

[0053] In the example embodiment, the sacrificial layer 50 may be made of a photosensitive organic material, such as a photosensitive resin material. Alternatively, the sacrificial layer 50 may be made of a photosensitive photoresist material. The sacrificial layer 50 may be fabricated using an inkjet-printing process.

[0054] In an exemplary embodiment, the sacrificial layer 50 may include one or a mixture of polymers such as polyimide (PI), polyacrylate, polyphenylene sulfide, polyarylate, cellulose acetate propionate, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethersulfone resin (PES), polycarbonate (PC), polyetherimide (PEI), cyclic olefin polymer (COP), silicone resin, polyaryl compound (PAR), or glass fiber reinforced plastic (FRP). When a laser irradiates a polymer such as polyimide, the polyimide will carbonize and decompose due to light absorption, thereby achieving the separation of the display substrate from the carrier substrate 10.

[0055] In one exemplary embodiment, the thickness of the sacrificial layer 50 may be set from 2.0 micrometers (μm) to 5.0 micrometers (μm).

[0056] In one exemplary embodiment, the refractive index of the sacrificial layer 50 may be set in the range of 1.65 to 1.80.

[0057] In one exemplary embodiment, the reflectivity of the optical film layer 40 is greater than its transmittance. The display substrate can utilize the semi-transparent and semi-reflective nature of the optical film layer 40 to reflect stripping light to the sacrificial layer 50, thereby improving the overall utilization efficiency of the stripping light.

[0058] Figure 3A This is a schematic diagram of the optical path of the stripped light in the display substrate according to an embodiment of the present disclosure. The optical film layer 40 can be a multi-layer structure. Figure 3A The structure of the optical film 40 is simplified and illustrated as a single-layer film. Figure 3BThis is a partially enlarged view of the stripping light path in the substrate according to an embodiment of this disclosure. For clarity, [the image is shown in the image]. Figure 3A , Figure 3B The display substrate is not filled with color; it is displayed with white frames.

[0059] In the example implementation, such as Figure 3A As shown, taking a laser beam as an example, the laser beam enters the sacrificial layer 50 from the side of the substrate 10 away from the sacrificial layer 50. Part of the laser beam passes through the optical film layer 40 and the substrate material layer 20 and is then reflected back to the sacrificial layer 50.

[0060] In the example implementation, such as Figure 3B As shown, the optical film layer 40 includes at least one first dielectric layer 401 and at least one second dielectric layer 402, and the refractive indices of the first dielectric layer 401 and the second dielectric layer 402 are different. In this embodiment, the refractive index of the first dielectric layer 401 is defined as being less than the refractive index of the second dielectric layer 402. The first dielectric layer 401 and the second dielectric layer 402 within the optical film layer 40 may be arranged in an overlapping manner along a direction away from the sacrificial layer 50. For example, along a direction away from the sacrificial layer 50, the first dielectric layer 401, the second dielectric layer 402, and the first dielectric layer 401 are arranged in an overlapping manner, such as... Figure 3B As shown. Alternatively, along the direction away from the sacrificial layer 50, the second dielectric layer, the first dielectric layer, the second dielectric layer, and the first dielectric layer are arranged in an overlapping manner.

[0061] like Figure 3B As shown, taking the optical film layer 40 as an example, which includes three layers, the layers are, in sequence, a first dielectric layer 401, a second dielectric layer 402, and a third dielectric layer 401, along the direction away from the sacrificial layer 50. By utilizing the difference in refractive index between the layers within the optical film layer 40, a semi-transparent and semi-reflective technical effect is achieved, thereby improving the utilization efficiency of stripped light.

[0062] According to optical principles, when light travels from one refractive index material to another, its path changes. At the interface between the two materials, refraction, reflection, or total internal reflection can occur. For example, when light travels from a material with a high refractive index to a material with a low refractive index, total internal reflection will occur at the interface if the angle of incidence exceeds the critical angle; otherwise, refraction will occur. By utilizing the different refractive indices of the various dielectric layers in the optical film 40, the proportion of laser light incident on the substrate material layer 20 can be reduced, and the proportion of light whose path changes can be increased, as well as the proportion of laser light reflected back to the sacrificial layer 50. This includes reflected light, refracted and then reflected light, or refracted, reflected, and then refracted light.

[0063] like Figure 3BAs shown, reflection of light is represented by solid arrows, and refraction of light is represented by dashed arrows. The refractive index of the first dielectric layer 401 is set to n1, and the refractive index of the second dielectric layer 402 is set to n2, where n2 is greater than n1. The refractive index of the medium through which the incident light passes is N1, and the refractive index of the medium through which the refracted light passes is N2. The angle of incidence is θ1, and the angle of refraction is θ2, satisfying the law of refraction N1sinθ1=N2sinθ2. During light transmission, N1, N2, θ1, and θ2 all change each time the light passes through the interface between the two materials with different refractive indices.

[0064] like Figure 3B As shown, taking a laser beam as an example: When light ray ① passes through the interface between the first dielectric layer 401 and the second dielectric layer 402, part of the light is reflected to form light ray ②. Light ray ② can perform a secondary etching on the sacrificial layer 50. Another part of light ray ① is refracted to form light ray ③. When refraction occurs, the law of refraction is satisfied: n1sinα1=n2sinα2. When light ray ③ passes through the interface between the second dielectric layer 402 and the first dielectric layer 401, part of the light is reflected to form light ray ④. Light ray ④ then passes through the interface between the second dielectric layer 402 and the first dielectric layer 401 again and is refracted to form light ray ⑥. Light ray ⑥ can perform a secondary etching on the sacrificial layer 50. Another part of light ray ③ is refracted to form light ray ⑤. When refraction occurs, the law of refraction is satisfied: n2sinα2=n1sinα3. When light ray ⑤ passes through the interface between the first dielectric layer 401 and the substrate material layer 20, part of the light is reflected to form light ray ⑦. When light ray ⑦ passes through the interface between the first dielectric layer 401 and the second dielectric layer 402, a portion of the light is refracted to form light ray ⑧. The refraction follows the law of refraction, n1sinα4=n2sinα5. When light ray ⑧ passes through the interface between the second dielectric layer 402 and the first dielectric layer 401, a portion of the light is refracted to form light ray ⑨. The refraction follows the law of refraction, n2sinα5=n1sinα6. Light ray ⑨ can perform a secondary etching on the sacrificial layer 50. The principle of multiple light rays is the same and will not be elaborated further here.

[0065] In some embodiments, the optical film layer 40 may include a plurality of first dielectric layers 401 and a plurality of second dielectric layers 402, the plurality of first dielectric layers 401 and the plurality of second dielectric layers 402 being arranged in an overlapping manner along a direction away from the sacrificial layer 50, the film layer adjacent to the substrate material layer 20 in the optical film layer 40 being the second dielectric layer 402, and the film layer adjacent to the sacrificial layer 50 in the optical film layer 40 being the second dielectric layer 402.

[0066] In an exemplary embodiment, the optical film layer 40 may include a plurality of first dielectric layers 401 and a plurality of second dielectric layers 402, the plurality of first dielectric layers 401 and the plurality of second dielectric layers 402 being arranged in an overlapping manner along a direction away from the sacrificial layer 50, the film layer adjacent to the substrate material layer 20 in the optical film layer 40 is the first dielectric layer 401, and the film layer adjacent to the sacrificial layer 50 in the optical film layer 40 is the first dielectric layer 401.

[0067] Figure 4A This is a schematic diagram of the structure of the optical film layer in the display substrate according to an embodiment of the present disclosure. Figure 1 In one exemplary embodiment, such as Figure 4A As shown, the optical film layer 40 may include three sublayers: a second dielectric layer 402 (taking an Nb2O5 layer as an example), a first dielectric layer 401 (taking a SiO2 layer as an example), and another second dielectric layer 402 (taking an Nb2O5 layer as an example), arranged sequentially. Along the direction away from the sacrificial layer 50, the second dielectric layer 402, the first dielectric layer 401, and the second dielectric layer 402 are arranged in an overlapping manner. The refractive index of the first dielectric layer 401 is less than the refractive index of the second dielectric layer 402.

[0068] In an exemplary embodiment, the optical film layer 40 adjacent to the substrate material layer 20 is a first dielectric layer 401, and the optical film layer 40 adjacent to the sacrificial layer 50 is also a first dielectric layer 401.

[0069] Figure 4B This is a schematic diagram of the structure of the optical film layer in the display substrate according to an embodiment of the present disclosure. Figure 2 In one exemplary embodiment, such as Figure 4B As shown, the optical film layer 40 may include seven sublayers, namely, a first dielectric layer 401 (taking SiO2 layer as an example), a second dielectric layer 402 (taking Nb2O5 layer as an example), a first dielectric layer 401, a second dielectric layer 402, a first dielectric layer 401, a second dielectric layer 402, and a first dielectric layer 401 arranged sequentially. Along the direction away from the sacrificial layer 50, the second dielectric layer 402, the first dielectric layer 401, the second dielectric layer 402, the second dielectric layer 402, the first dielectric layer 401, the second dielectric layer 402, and the first dielectric layer 401 are arranged in an overlapping manner. The refractive index of the first dielectric layer 401 is less than the refractive index of the second dielectric layer 402.

[0070] In some embodiments, the optical film layer may further include other numbers of first dielectric layers and second dielectric layers, provided that the refractive indices of the first dielectric layer and the second dielectric layer are different, and the first dielectric layer and the second dielectric layer are arranged in an overlapping manner along the direction away from the sacrificial layer. Further details of the embodiments disclosed herein will not be elaborated upon.

[0071] In this embodiment, the display substrate has an optical film layer 40 with a multi-layer structure. This structure can be achieved by alternating layers with different refractive indices, such as a first dielectric layer 401 and a second dielectric layer 402. This allows the optical film layer 40 to reflect laser light of different wavelengths, enhancing the versatility of display products. For example, in actual production, the efficiency of laser stripping of the display substrate can be improved by changing the material combination of multiple layers within the optical film layer 40 without adjusting existing production equipment.

[0072] Table 1 illustrates the structure of the optical film layer to be simulated. The substrate can be glass. Along the direction away from the substrate 10, the optical film layer to be simulated includes a second dielectric layer (Nb2O5), a first dielectric layer (SiO2), and a second dielectric layer (Nb2O5) arranged sequentially along this direction. The thicknesses in Table 1 represent the thicknesses of the corresponding film layers. A thickness of "0" indicates that the thickness of that layer is set to 0 in the simulation software, meaning that the actual optical film layer does not contain that layer.

[0073] Table 1

[0074]

[0075] Figure 5 The image shows a laser reflection curve obtained by simulating an optical film layer in the substrate according to an embodiment of this disclosure. Laser reflection simulation experiments were performed on the optical films shown in Table 1 above, and the simulation results are as follows. Figure 5 As shown. Among them, Figure 5 The horizontal axis represents the wavelength of the laser in the simulation experiment; Figure 5 The vertical axis represents the reflectance of the optical film to the laser in the simulation experiment.

[0076] The experimental results above show that different reflectivities can be obtained based on the same optical film layer 40 due to different laser wavelengths. For example, when the laser wavelength is 400 nanometers (nm), the reflectivity of the optical film layer can reach 60%. In actual production, the number and material of the dielectric layers inside the optical film layer 40 can be adjusted according to the laser wavelength and the reflectivity required by the design.

[0077] In the actual production of display substrates, different lasers can be selected to obtain the required laser wavelength. The wavelength range of lasers is from 375 nanometers to 1650 nanometers. For example, blue-violet lasers have wavelengths of 375 nanometers and 405 nanometers. Blue lasers have wavelengths of 450 nanometers, 457 nanometers, and 473 nanometers. Green lasers have a wavelength of 532 nanometers. Yellow lasers have a wavelength of 589 nanometers. Red lasers have wavelengths of 635 nanometers and 660 nanometers, etc.

[0078] Excimer lasers can also be selected. An excimer laser is a laser emitted when molecules in a mixture of inert and halogen gases excited by an electron beam transition to their ground state. Excimer lasers emit ultraviolet light with a wavelength range of 157 nm to 353 nm. Common excimer laser wavelengths are 157 nm, 193 nm, 248 nm, and 308 nm.

[0079] In the example embodiment, both the first dielectric layer 401 and the second dielectric layer 402 can be made of inorganic materials. For example, the material of the first dielectric layer 401 may include silicon oxynitride (SiO2). x N y The material of the second dielectric layer 402 may be any one of silicon oxynitride (SiN), silicon oxide (SiO), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium dioxide (TiO2), niobium pentoxide (Nb2O5), etc. x N y The dielectric material can be any one of the following: silicon nitride (SiN), silicon oxide (SiO), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium dioxide (TiO2), or niobium pentoxide (Nb2O5). The only requirement is that the refractive index of the second dielectric layer 402 is greater than that of the first dielectric layer 401.

[0080] In an exemplary embodiment, the refractive index of the first dielectric layer 401 can be set to a range of 1.4 to 1.6, and the refractive index of the second dielectric layer 402 can be set to a range of 2.0 to 2.3. The combined use of these two dielectric layers with different refractive indices can achieve semi-transparent and semi-reflective optical properties, thereby improving the reflectivity of stripped light and increasing light utilization.

[0081] In an exemplary embodiment, other layers may be disposed between adjacent first dielectric layers 401 and second dielectric layers 402 in the optical film layer 40. For example, a third dielectric layer may be disposed between adjacent first dielectric layers 401 and second dielectric layers 402 in the optical film layer 40. The refractive index of the third dielectric layer is greater than that of the first dielectric layer and less than that of the second dielectric layer. The material of the third dielectric layer may include silicon oxynitride (SiO2). x N y Any one of the following: silicon nitride (SiN), silicon oxide (SiO), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium dioxide (TiO2), niobium pentoxide (Nb2O5).

[0082] In some embodiments, a fourth or fifth dielectric layer may be provided between adjacent first dielectric layers 401 and second dielectric layers 402. The refractive indices of the first, second, third, fourth, and fifth dielectric layers are all different, and the arrangement of the multiple dielectric layers is not limited here.

[0083] In an exemplary embodiment, the refractive index of the film layer 40 adjacent to the substrate material layer 20 is greater than the refractive index of the substrate material layer 20, which can increase the rate at which light returns to the optical film layer 40.

[0084] In an exemplary embodiment, the refractive index of the film layer 40 adjacent to the sacrificial layer 50 is greater than the refractive index of the sacrificial layer 50, which can improve the light return rate.

[0085] In an exemplary embodiment, the thickness of the optical film layer 40 can be set from 2.0 micrometers (μm) to 5.0 micrometers (μm). The thickness of the optical film layer 40 can be adjusted according to different incident light energies.

[0086] In an exemplary embodiment, the optical film layer 40 has higher stiffness than the sacrificial layer 50, that is, the stiffness of the optical film layer 40 is greater than that of the sacrificial layer 50. This allows the optical film layer 40 to provide stable support for the substrate material layer 20 and also to act as a protective layer. When small molecule foreign matter is deposited on the surface of the substrate 10, the optical film layer 40 can effectively isolate the adverse effects of the foreign matter on the substrate material layer 20. For example, the optical film layer 40 can reduce the probability of defects such as blistering in the substrate material layer 20 and improve the overall pass rate of the display product.

[0087] In an example embodiment, the substrate material layer 20 may include one or a mixture of polymers such as polyimide (PI), polyacrylate, polyphenylene sulfide, polyarylate, cellulose acetate propionate, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethersulfone resin (PES), polycarbonate (PC), polyetherimide (PEI), cyclic olefin polymer (COP), silicone resin, polyaryl compound (PAR), or glass fiber reinforced plastic (FRP). The substrate material layer 20 may be made of the same material as the sacrificial layer 50.

[0088] In an exemplary embodiment, the thickness of the substrate material layer 20 may be set from 6.0 micrometers (μm) to 50 micrometers (μm).

[0089] In one exemplary embodiment, such as Figure 2As shown, the display substrate in this embodiment further includes a circuit structure layer 301, a conductive layer 302, and a light-emitting element 60. The circuit structure layer 301 is disposed on the substrate structure layer. The circuit structure layer 301 may be disposed on the side of the substrate material layer 20 away from the sacrificial layer 50. The circuit structure layer 301 includes a driving transistor (TFT). The driving transistor may include a gate electrode, a gate insulating layer, a semiconductor layer, a source electrode, and a drain electrode. The circuit structure layer 301 is used to drive the light-emitting element 60 to emit light.

[0090] In one exemplary embodiment, the semiconductor layer driving the transistor may include silicon, such as amorphous silicon (a-Si), polycrystalline silicon (poly-Si), or low-temperature polycrystalline silicon, or may include oxides, such as indium gallium zinc oxide (IGZO), but the embodiments of this disclosure are not limited thereto.

[0091] In an exemplary embodiment, the conductive layer 302 includes a first electrode and a second electrode. One end of the first electrode and the second electrode are electrically connected to the circuit structure layer 301, and the other end of the first electrode and the second electrode are electrically connected to the light-emitting element 60. The light-emitting element 60 is electrically connected to the circuit structure layer 301 through the first electrode and the second electrode, thereby enabling the circuit structure layer 301 to drive the light-emitting element 60 to emit light.

[0092] like Figure 2 As shown in the embodiment of this disclosure, the substrate further includes an insulating layer 303 located between the circuit structure layer 301 and the conductive layer 302. An opening 304 is provided on the insulating layer 303, penetrating the thickness of the insulating layer 303 (along the Z direction). The opening 304 exposes a portion of the circuit structure layer 301. A first electrode or a second electrode is electrically connected to the circuit structure layer 301 through the opening 304.

[0093] In an exemplary embodiment, the insulating layer 303 may be made of organic materials, such as polyamide, polyurethane, phenolic resin, polysiloxane, etc. Using organic materials for the insulating layer 303 not only provides better insulation but also better flexibility.

[0094] In one exemplary embodiment, such as Figure 2 As shown, the light-emitting element 60 can be a micro-LED or a sub-millimeter light-emitting diode.

[0095] In one exemplary embodiment, such as Figure 2As shown in the embodiment of this disclosure, the substrate further includes a protective layer 305 located on the side of the conductive layer 302 away from the circuit structure layer 301. A via 306 is provided in the protective layer 305, through which the light-emitting element 60 is connected to the first electrode and the second electrode. The protective layer 305 can be made of organic materials, such as polymers like acrylates, epoxy resins, and polyurethanes. Alternatively, the protective layer 305 can be made of inorganic materials, such as silicon oxynitride (SiOxNy), silicon nitride (SiN), silicon oxide (SiO), or silicon dioxide (SiO2). The protective layer 305 prevents the metal material contained in the conductive layer 302 from being oxidized.

[0096] The "patterning process" mentioned in the embodiments of this disclosure includes processes such as depositing a film layer, coating photoresist, mask exposure, development, etching, and photoresist stripping, which are mature fabrication processes in related technologies. Deposition can be performed using known processes such as sputtering and chemical vapor deposition, coating can be performed using known coating processes, and etching can be performed using known methods; no specific limitations are made here.

[0097] The method for preparing a display substrate may include the following steps:

[0098] (1) Provide a substrate.

[0099] Providing a carrier substrate may include operations such as cleaning and drying the carrier substrate. The carrier substrate can be made of a rigid material, which allows it to provide stable support for the display substrate while also having high laser transmittance, thereby improving the peeling efficiency between the display substrate and the carrier substrate.

[0100] For example, quartz glass can be used as the substrate. Quartz glass is an amorphous material with a single SiO2 component. Its microstructure is a simple network composed of SiO2 tetrahedral structural units. Due to the large Si-O chemical bond energy and the relatively compact microstructure of quartz glass, it has excellent optical properties and high transmittance in a continuous wavelength range from ultraviolet to infrared.

[0101] (2) Prepare the sacrificial layer.

[0102] The preparation of the sacrificial layer includes forming the sacrificial layer using methods such as coating. The sacrificial layer can be obtained through a single coating operation or through multiple coating operations.

[0103] Coating processes include blade coating, roller coating, ultrasonic spraying, and slot coating.

[0104] Alternatively, the sacrificial layer can be formed using methods such as inkjet printing, screen printing, flash evaporation, or plasma-enhanced chemical vapor deposition (PECVD).

[0105] (3) Prepare optical film.

[0106] The preparation of optical films includes forming optical films using methods such as PECVD, atomic layer deposition (PEALD), or magnetron sputtering.

[0107] (4) Prepare the substrate material layer.

[0108] Preparation of the substrate material layer: The substrate material layer is formed by coating processes and other methods.

[0109] Alternatively, the substrate material layer can be formed using methods such as inkjet printing, screen printing, flash evaporation, or PECVD.

[0110] The process for preparing the substrate material layer can be set to be the same as the process for preparing the sacrificial layer, so as to reduce the switching between different processes and reduce manufacturing input.

[0111] Alternatively, the sacrificial layer, optical film layer, and substrate material layer can be manufactured using the same process to reduce the switching between different processes and thus reduce manufacturing costs.

[0112] (5) Fabricate the circuit structure layer.

[0113] The fabrication of the circuit structure layer includes forming the circuit structure layer using methods such as magnetron sputtering.

[0114] (6) Prepare the insulating layer.

[0115] The preparation of the insulating layer includes forming the insulating layer using methods such as PECVD, atomic layer deposition, or magnetron sputtering. The insulating layer contains openings that expose the circuit structure layers.

[0116] (7) Prepare a conductive layer.

[0117] The fabrication of the conductive layer includes forming the conductive layer using methods such as magnetron sputtering. The conductive layer includes a first electrode and a second electrode, which are electrically connected to the circuit structure layer through openings.

[0118] (8) Prepare a protective layer.

[0119] The preparation of the protective layer includes forming the protective layer using methods such as PECVD, atomic layer deposition, or magnetron sputtering. The protective layer contains vias.

[0120] (9) Install the light-emitting element.

[0121] Mounting the light-emitting element includes: using a die bond process to electrically connect the light-emitting element to the first and second electrodes through vias. The die bond process is also known as die bonding or die mounting. Die bond involves using an adhesive, typically conductive or insulating adhesive for LEDs, to bond the chip to a designated area on a support, forming a thermal or electrical path and providing the necessary conditions for subsequent wire bonding.

[0122] Alternatively, a soldering process can be used to electrically connect the light-emitting element to the first and second electrodes through vias. For example, solder metal can be printed onto the connection pattern location using a printing method (e.g., as shown in the image). Figure 2 As shown, the welding metal is printed at the via 306, and then the light-emitting element is welded to the corresponding connection pattern position.

[0123] (10) Peel off the display substrate.

[0124] The process of peeling off the display substrate includes: using a laser to irradiate the sacrificial layer from the side of the carrier substrate away from the sacrificial layer, that is, allowing the laser to pass through the carrier substrate and then irradiate the sacrificial layer, thereby peeling the sacrificial layer off from the carrier substrate to obtain the display substrate.

[0125] This disclosure also provides a method for fabricating a display substrate. The method includes:

[0126] A sacrificial layer is formed on the carrier substrate;

[0127] An optical film layer is formed on the sacrificial layer;

[0128] A substrate material layer is formed on the optical film layer;

[0129] The sacrificial layer is irradiated from the side of the carrier substrate away from the sacrificial layer using a stripping ray, so as to cause the sacrificial layer to peel off from the carrier substrate; wherein the reflectivity of the optical film layer is greater than the transmittance of the optical film layer.

[0130] As can be seen from the above technical solution and its preparation process, the display substrate provided in this embodiment can be laser-peeled from the carrier substrate using a laser lift-off process. The display substrate is configured with an optical film layer whose reflectivity is greater than its transmittance, which reduces the proportion of lift-off light penetrating the substrate material layer. This avoids damage to the circuit structure layers within the display substrate, improves the product yield, and reduces the overall manufacturing cost of the display product. Furthermore, the preparation method of the display substrate in this embodiment can be achieved using existing mature preparation equipment, requiring minimal modification to existing processes. The preparation process is simple, with low manufacturing cost and high precision, showing promising application prospects.

[0131] This disclosure also provides a display device. The display device includes the display substrate described in any of the above embodiments. The display device can be any product or component with display functionality, such as a mobile phone, tablet computer, television, laptop computer, digital photo frame, or navigator.

[0132] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A display substrate, comprising a substrate structure layer; the substrate structure layer comprising a substrate material layer, a sacrificial layer, and an optical film layer disposed between the substrate material layer and the sacrificial layer; the reflectivity of the optical film layer is greater than the transmittance of the optical film layer; The optical film layer includes at least one first dielectric layer and at least one second dielectric layer, wherein the refractive index of the first dielectric layer is less than the refractive index of the second dielectric layer; the first dielectric layer and the second dielectric layer are overlapped along a direction away from the sacrificial layer; the material of the first dielectric layer is Nb2O5, and the material of the second dielectric layer is SiO2, or the refractive index of the first dielectric layer is in the range of 1.4 to 1.6, and the refractive index of the second dielectric layer is in the range of 2.0 to 2.3; The refractive index of the optical film layer adjacent to the substrate material layer is greater than the refractive index of the substrate material layer, and the refractive index of the optical film layer adjacent to the sacrificial layer is greater than the refractive index of the sacrificial layer. The base material layer includes one or a mixture of multiple of the following: polyimide, polyacrylate, polyphenylene sulfide, polyarylate, cellulose acetate propionate, polyethylene naphthalate, polyethylene terephthalate, polyethersulfone resin, polycarbonate, polyetherimide, cyclic olefin polymer, silicone resin, polyaryl compound, or glass fiber reinforced plastic. The refractive index of the sacrificial layer is in the range of 1.65 to 1.

80.

2. The display substrate as claimed in claim 1, wherein, The optical film layer adjacent to the substrate material layer is the first dielectric layer, and the optical film layer adjacent to the sacrificial layer is also the first dielectric layer.

3. The display substrate as described in claim 1, wherein, The optical film layer adjacent to the substrate material layer is the second dielectric layer, and the optical film layer adjacent to the sacrificial layer is the second dielectric layer.

4. The display substrate as described in any one of claims 1 to 3, wherein, Both the first dielectric layer and the second dielectric layer are made of inorganic materials.

5. The display substrate as described in any one of claims 1 to 3, wherein, The thickness of the sacrificial layer is 2.0 micrometers to 5.0 micrometers.

6. The display substrate as described in any one of claims 1 to 3, wherein, The sacrificial layer is made of photosensitive organic material or photoresist material.

7. The display substrate as described in any one of claims 1 to 3, wherein, The material of the sacrificial layer is the same as the material of the base material layer.

8. The display substrate as described in any one of claims 1 to 3, wherein, The display substrate further includes a circuit structure layer disposed on the side of the substrate material layer away from the sacrificial layer.

9. The display substrate as claimed in claim 8, wherein, The display substrate further includes a light-emitting element disposed on the side of the circuit structure layer away from the substrate structure layer, and the light-emitting element is connected to the circuit structure layer.

10. The display substrate as claimed in claim 9, wherein, The light-emitting element is a miniature light-emitting diode or a sub-millimeter light-emitting diode.

11. A display device comprising a display substrate as described in any one of claims 1 to 10.

12. A method for preparing a display substrate, comprising: A sacrificial layer is formed on a carrier substrate; the refractive index of the sacrificial layer is in the range of 1.65 to 1.

80. An optical film layer is formed on the sacrificial layer; The optical film layer includes at least one first dielectric layer and at least one second dielectric layer, wherein the refractive index of the first dielectric layer is less than the refractive index of the second dielectric layer; the first dielectric layer and the second dielectric layer are overlapped along a direction away from the sacrificial layer; the material of the first dielectric layer is Nb2O5, and the material of the second dielectric layer is SiO2, or the refractive index of the first dielectric layer is in the range of 1.4 to 1.6, and the refractive index of the second dielectric layer is in the range of 2.0 to 2.3; A substrate material layer is formed on the optical film layer; the refractive index of the film layer adjacent to the substrate material layer in the optical film layer is greater than the refractive index of the substrate material layer, and the refractive index of the film layer adjacent to the sacrificial layer in the optical film layer is greater than the refractive index of the sacrificial layer; the substrate material layer includes one or a mixture of multiple of the following: polyimide, polyacrylate, polyphenylene sulfide, polyarylate, cellulose acetate propionate, polyethylene naphthalate, polyethylene terephthalate, polyethersulfone resin, polycarbonate, polyetherimide, cyclic olefin polymer, silicone resin, polyaryl compound, or glass fiber reinforced plastic; The sacrificial layer is irradiated from the side of the carrier substrate away from the sacrificial layer using a stripping ray, so as to cause the sacrificial layer to peel off from the carrier substrate; wherein the reflectivity of the optical film layer is greater than the transmittance of the optical film layer.

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