Display substrate, preparation method thereof and display device

Abstract

The invention provides a display substrate, a preparation method thereof and a display device, belongs to the technical field of display, and can solve the problem that the front light emitting efficiency of an existing display substrate is low. The display substrate comprises a substrate body, a plurality of light-emitting devices located on the substrate body, an optical coupling layer located on the sides, away from the substrate body, of the light-emitting devices, and a packaging layer located on the side, away from the substrate body, of the optical coupling layer. The display substrate further comprises a photorefractive crystal layer located between the optical coupling layer and the packaging layer. The refractive index of the photorefractive crystal layer is adjustable and is between the refractive index of the optical coupling layer and the refractive index of the packaging layer.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of display, and particularly relates to a display substrate, a preparation method thereof, and a display device. Background Art

[0002] An organic light-emitting diode (OLED) is a light-emitting device that uses an organic solid semiconductor as a light-emitting material. Due to its advantages such as simple preparation process, low cost, low power consumption, high luminous brightness, and wide working temperature range, it has broad application prospects.

[0003] Currently, in an OLED display substrate, since the light emitted by the OLED device has a certain degree of divergence, the light with a larger emission angle is likely to exit from the side of the display substrate, affecting the front light extraction efficiency of the OLED device and causing light waste. Therefore, how to improve the front light extraction efficiency of the OLED device has always been a problem that researchers in various fields strive to solve. Summary of the Invention

[0004] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a display substrate, a preparation method thereof, and a display device.

[0005] In a first aspect, an embodiment of the present disclosure provides a display substrate, which includes: a substrate, a plurality of light-emitting devices located on the substrate, an optical coupling layer located on a side of the light-emitting devices away from the substrate, and a packaging layer located on a side of the optical coupling layer away from the substrate; the display substrate further includes: a photorefractive crystal layer located between the optical coupling layer and the packaging layer;

[0006] The refractive index of the photorefractive crystal layer is adjustable and is between the refractive index of the optical coupling layer and the refractive index of the packaging layer.

[0007] In some embodiments, the display substrate further includes: a first electrode and a second electrode;

[0008] The first electrode and the second electrode are arranged at intervals and are both located on a side of the photorefractive crystal layer close to the optical coupling layer.

[0009] In some embodiments, the display substrate further includes: a first electrode and a second electrode;

[0010] The first electrode is located on a side of the photorefractive crystal layer close to the optical coupling layer;

[0011] The second electrode is located on a side of the photorefractive crystal layer close to the packaging layer.

[0012] In some embodiments, the display substrate further includes: a temperature adjustment layer;

[0013] The temperature adjustment layer is located on a side of the photorefractive crystal layer close to the optical coupling layer.

[0014] In some embodiments, the material of the photorefractive crystal layer includes at least one of: lithium niobate crystal, potassium dihydrogen phosphate crystal, low-temperature phase barium metaborate crystal, rubidium titanyl phosphate crystal, and lanthanum gallium silicate crystal.

[0015] In some embodiments, the photorefractive crystal layer includes: a plurality of nanoparticles arranged in an array;

[0016] The orthographic projection of the nanoparticles on the substrate substantially overlaps with the orthographic projection of the light-emitting device on the substrate.

[0017] In some embodiments, the light-emitting device includes: a red light-emitting device, a green light-emitting device, and a blue light-emitting device.

[0018] In a second aspect, an embodiment of the present disclosure provides a display device, and the display device includes the display substrate provided in the first aspect above.

[0019] In a third aspect, an embodiment of the present disclosure provides a method for manufacturing a display substrate, for manufacturing the display substrate provided in the first aspect above, and the method for manufacturing the display substrate includes:

[0020] Forming a plurality of light-emitting devices and an optical coupling layer on a substrate in sequence;

[0021] Mounting a photorefractive crystal on a support substrate and processing the photorefractive crystal to form a photorefractive crystal layer;

[0022] Peeling the photorefractive crystal layer from the support substrate;

[0023] Attaching the photorefractive crystal layer to the optical coupling layer;

[0024] Forming a packaging layer on the photorefractive crystal layer.

[0025] In some embodiments, before peeling the photorefractive crystal layer from the support substrate, it further includes:

[0026] Inducing the photorefractive crystal layer through a specific chemical reaction in a physical process, or performing a chemical reaction under the conditions in a physical process, such that the photorefractive crystal layer forms a plurality of nanoparticles arranged in an array. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of an exemplary display substrate.

[0028] Figure 2 This is a schematic structural diagram of a display substrate provided by an embodiment of the present disclosure.

[0029] Figure 3 This is another schematic structural diagram of a display substrate provided by an embodiment of the present disclosure.

[0030] Figure 4 This is yet another schematic structural diagram of a display substrate provided by an embodiment of the present disclosure.

[0031] Figure 5 This is still another schematic structural diagram of a display substrate provided by an embodiment of the present disclosure.

[0032] Figure 6 This is a structural diagram of a photorefractive crystal layer under an electron microscope.

[0033] Figure 7 This is a schematic flow diagram of a method for manufacturing a display substrate provided by an embodiment of the present disclosure. Detailed implementation manners

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present disclosure. Components of the embodiments of the present disclosure described and illustrated herein generally may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the present disclosure claimed, but is merely representative of selected embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts fall within the scope of protection of the present disclosure. Without conflict, the various embodiments of the present disclosure and the features in the embodiments may be combined with each other.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. Similarly, terms such as "a", "an", or "the" do not denote a limitation of quantity, but mean that there is at least one. The terms "including" or "comprising" and the like mean that the elements or items appearing before the term cover the elements or items listed after the term and their equivalents, without excluding other elements or items.

[0036] As used in this disclosure, "a plurality of" or "several" means two or more. "And / or" describes the relationship between related objects and indicates that there can be three relationships. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the related objects before and after are in an "or" relationship.

[0037] Figure 1 FIG. is a schematic structural diagram of an exemplary display substrate, as Figure 1 shown, the display substrate includes: a substrate 101, a plurality of light-emitting devices 102 located on the substrate 101, an optical coupling layer 103 located on the side of the light-emitting devices 102 facing away from the substrate 101, and a packaging layer 104 located on the side of the optical coupling layer 103 facing away from the substrate 101.

[0038] The substrate 101 can support other film layers and devices thereon. The light-emitting device 102 can specifically be an OLED device, such as a red OLED device, a green OLED device, and a blue OLED device, etc. Each light-emitting device can emit light of different colors to achieve color display. The optical coupling layer 103 can improve the light extraction efficiency of the light-emitting device 103. The packaging layer 104 can package the light-emitting device 102 to prevent the intrusion of gases such as water and oxygen.

[0039] Currently, since the light emitted by the OLED device has a certain degree of divergence, the light with a larger emission angle is likely to emit from the side of the display substrate, affecting the front light emission efficiency of the OLED device and causing light waste. And generally, a sealing glue or other structures are provided on the side of the display substrate, and its color is generally black, which can absorb the light emitted from the side of the display substrate, further reducing the front light emission efficiency of the OLED device, affecting the display effect, and reducing the user experience.

[0040] In order to solve at least one of the above technical problems, embodiments of the present disclosure provide a display substrate, a preparation method thereof, and a display device. Below, in conjunction with the drawings and specific embodiments, the display substrate, the preparation method thereof, and the display device provided by the embodiments of the present disclosure will be further described in detail.

[0041] In a first aspect, embodiments of the present disclosure provide a display substrate, Figure 2 FIG. is a schematic structural diagram of a display substrate provided by an embodiment of the present disclosure, as Figure 2As shown in the figure, the display substrate includes: a substrate 101, a plurality of light-emitting devices 102 located on the substrate 101, an optical coupling layer 103 located on the side of the light-emitting devices 102 facing away from the substrate 101, and a packaging layer 104 located on the side of the optical coupling layer 103 facing away from the substrate 101; the display substrate further includes: a photorefractive crystal layer 105 located between the optical coupling layer 103 and the packaging layer 104; the refractive index of the photorefractive crystal layer 105 is adjustable and is between the refractive index of the optical coupling layer 103 and the refractive index of the packaging layer 104.

[0042] The substrate 101 can be made of a rigid material such as glass, which can improve the bearing capacity of the substrate 101 for other film layers thereon. Of course, the substrate 101 can also be made of a flexible material such as polyimide (PI), which can improve the anti-bending and anti-stretching performance of the entire display substrate, and avoid the substrate 101 being broken due to stress generated during bending, stretching, and twisting, resulting in an open-circuit defect. In practical applications, the material of the substrate 101 can be reasonably selected according to actual needs to ensure that the display substrate has good performance.

[0043] The light-emitting device 102 can specifically be an organic light-emitting diode (OLED), a light-emitting diode (LED), a quantum dot light-emitting diode (QLED), a mini light-emitting diode (Mini LED), a micro light-emitting diode (Micro LED), etc., which will not be limited here. In the embodiments of the present disclosure, the light-emitting device 102 will be described by taking the OLED device as an example. A pixel driving circuit (not shown in the figure) is also provided in the display substrate to drive each light-emitting device 102 to emit light. The pixel driving circuit can specifically be a 4T2C (i.e., 4 transistors and 2 capacitors) structure, a 3T1C (i.e., 3 transistors and 1 capacitor) structure, a 7T1C (i.e., 7 transistors and 1 capacitor) structure, a 5T1C (i.e., 5 transistors and 1 capacitor) structure, an 8T1C (i.e., 8 transistors and 1 capacitor) structure, or an 8T2C (i.e., 8 transistors and 2 capacitors) structure, etc. The specific connection manner of the pixel driving circuit can refer to the connection manner in the related art and will not be limited here.

[0044] Specifically, the light-emitting device 102 may include: an anode 1021 and a cathode 1022 which are oppositely arranged, and an organic light-emitting layer 1023 located between the anode 1021 and the cathode 1022. Further, the light-emitting device 102 further includes: a hole transport layer 1024, an electron blocking layer 1025 and other film layers located between the anode 1021 and the organic light-emitting layer 1023, and an electron transport layer 1026 and a hole blocking layer 1027 located between the cathode 1022 and the organic light-emitting layer 1023. The holes transported at the anode 1021 and the electrons transported at the cathode 1022 can be respectively transported to the organic light-emitting layer 1023 through the hole transport layer 1024, the electron blocking layer 1025, the electron transport layer 1026 and the hole blocking layer 1027, and excitons are formed in the organic light-emitting layer 1023, and energy level transitions occur to emit light.

[0045] The optical coupling layer 103 can be made of high-performance organic materials such as cycloolefin polymers. It can reduce the light loss that occurs when the light emitted by the light-emitting device 102 is repeatedly reflected in the electrodes (anode 1021, cathode 1022), so that the light is emitted toward the front, and can improve the extraction rate of the light and the light extraction efficiency. The refractive index of the optical coupling layer 103 is generally 1.5 to 1.7.

[0046] The encapsulation layer 104 can be made of a multi-layer structure. The encapsulation layer 104 includes: a first inorganic encapsulation layer 1041, a second inorganic encapsulation layer 1042, and an organic encapsulation layer 1043 located between the first inorganic encapsulation layer 1041 and the second inorganic encapsulation layer 1042, such as a silicon nitride SiN + ink + silicon nitride SiN structure. The first inorganic encapsulation layer 1041 and the second inorganic encapsulation layer 1042 can prevent gases such as water and oxygen from invading and damaging the light-emitting device 102 therein. The organic encapsulation layer 1043 can increase the overall flexibility of the encapsulation layer 104 and avoid damage to the encapsulation layer 104 caused by external forces during application, resulting in encapsulation failure. The refractive index of the encapsulation layer 104 is generally 1.7 to 2.2.

[0047] The photorefractive crystal layer 105 can be made of a photorefractive crystal with an adjustable refractive index, such as at least one of lithium niobate crystal, potassium dihydrogen phosphate crystal, low-temperature phase barium metaborate crystal, rubidium titanyl phosphate crystal and lanthanum gallium silicate crystal. In the embodiments of the present disclosure, the lithium niobate crystal will be taken as an example for illustration. The implementation principles of other materials are similar and will not be described in detail.

[0048] After photorefractive crystals such as lithium niobate are irradiated by light, their effective refractive index is:

[0049]

[0050] Among them, n 0，fare the initial value and the final value of the refractive index of the photorefractive crystal layer 104, a is the thickness of the photorefractive crystal layer 104, n po is the undisturbed refractive index of the photorefractive crystal layer 104 when not subjected to light radiation, r eff is the effective electro-optic coefficient, k B is the Boltzmann constant, T is the temperature, I d is the dark current.

[0051] In practical applications, the refractive index of the photorefractive crystal layer 104 is generally 1.5 - 2.2. It can be seen from the above formula that by changing parameters such as the temperature and electric field of the photorefractive crystal layer 104, the refractive index of the photorefractive crystal layer 104 can be adjusted so that the refractive index of the photorefractive crystal layer 104 is between the refractive index of the optical coupling layer 103 and the refractive index of the encapsulation layer 104.

[0052] In the display substrate provided by the embodiments of the present disclosure, the optical coupling layer 103 and the encapsulation layer 104 cover each light-emitting device 102 on the substrate 101, wherein the refractive index of the optical coupling layer 103 is less than the refractive index of the encapsulation layer 105, and there is a certain gap between them. The photorefractive crystal layer 105 is located between the optical coupling layer 104 and the encapsulation layer 105. Due to the material characteristics of the photorefractive crystal, by changing parameters such as the temperature and electric field of the photorefractive crystal layer 104, the refractive index of the photorefractive crystal layer 105 can be adjusted so that the refractive index of the photorefractive crystal layer 105 is between the optical coupling layer 103 and the encapsulation layer 104. According to the refraction law n 1 sinθ 1 = n 2 sinθ 2 (n 1 、n 2 are the refractive indices of adjacent different film layers, θ 1 、θ 2 are the angles between the light ray and the normal at the interface of adjacent different film layers), the refractive index can be effectively determined. For example, the refractive index of the photorefractive crystal layer 105 can be controlled to be around 1.9 - 2.0. Due to the difference in refractive index, the propagation direction of the light ray emitted from the optical coupling layer 103 changes. The light ray with a larger exit angle can be redirected to the front direction of the display substrate, which is more conducive to the light rays converging towards the front direction of the display substrate. In this way, the light rays emitted from the side of the display substrate can be reduced, the light extraction efficiency of the display substrate can be improved, thereby improving the display effect and further enhancing the user experience.

[0053] Figure 3 is a schematic structural diagram of another display substrate provided by the embodiments of the present disclosure, as Figure 3As shown, the display substrate further includes: a first electrode 106 and a second electrode 107; the first electrode 106 and the second electrode 107 are arranged at intervals, and both are located on the side of the photorefractive crystal layer 105 close to the optical coupling layer 103.

[0054] The first electrode 106 and the second electrode 107 can be arranged in the same layer, that is, both are located on the side of the photorefractive crystal layer 105 close to the optical coupling layer 103. The first electrode 106 and the second electrode 107 can be single-layer or multi-layer, and the materials can be selected from metals, metal compounds, and combinations of metals and metal compounds. Exemplarily, the materials of the first electrode 106 and the second electrode 107 can be selected from at least one of indium tin oxide (ITO), lithium oxide (Li2O), calcium oxide (CaO), lithium fluoride (LiF), magnesium fluoride (MgF2), silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), Ca-LiF alloy, AI-LiF alloy, molybdenum (Mo), titanium (Ti), indium (In), tin (Sn), and zinc (Zn).

[0055] The voltage signals input to the first electrode 106 and the second electrode 107 are different, and an electric field can be formed between them. Under the action of the electric field, the refractive index of the photorefractive crystal layer 105 can be adjusted so that the refractive index of the photorefractive crystal layer 105 is between the optical coupling layer 103 and the encapsulation layer 104. According to the refraction law n 1 sinθ 1 =n 2 sinθ 2 (n 1 、n 2 are the refractive indices of adjacent different film layers, and θ 1 、θ 2 are the angles between the light ray and the normal at the interface of adjacent different film layers), the refractive index can be effectively determined. For example, the refractive index of the photorefractive crystal layer 105 can be controlled to be around 1.9 - 2.0. Due to the difference in refractive index, the propagation direction of the light ray emitted from the optical coupling layer 103 changes. The light ray with a larger exit angle can be redirected to the front direction of the display substrate, which is more conducive to the light rays converging towards the front direction of the display substrate. In this way, the light rays emitted from the side of the display substrate can be reduced, the light extraction efficiency of the display substrate can be improved, thereby improving the display effect, and further enhancing the user experience.

[0056] Figure 4 This is a schematic structural diagram of another display substrate provided by an embodiment of the present disclosure. As Figure 4As shown, the display substrate further includes: a first electrode 106 and a second electrode 107; the first electrode 106 is located on the side of the photorefractive crystal layer 105 close to the optical coupling layer 103; the second electrode 107 is located on the side of the photorefractive crystal layer 105 close to the encapsulation layer 104.

[0057] Figure 4 The display substrate shown in Figure 3 is different from the display substrate shown in Figure 3 in that the first electrode 106 and the second electrode 107 in the display substrate shown in are provided on the same layer and are both located on the same side of the photorefractive crystal layer 105. Figure 4 In the display substrate shown in, the first electrode 106 and the second electrode 107 are located in different film layers and are respectively located on both sides of the photorefractive crystal layer 105.

[0058] The voltage signals input to the first electrode 106 and the second electrode 107 are different, and an electric field can be formed between them. Under the action of the electric field, the refractive index of the photorefractive crystal layer 105 can be adjusted so that the refractive index of the photorefractive crystal layer 105 is between the optical coupling layer 103 and the encapsulation layer 104. According to the law of refraction n 1 sinθ 1 =n 2 sinθ 2 (n 1 , n 2 are the refractive indices of adjacent different film layers, and θ 1 , θ 2 are the angles between the light ray and the normal at the interface of adjacent different film layers), the refractive index can be effectively determined. For example, the refractive index of the photorefractive crystal layer 105 can be controlled to be around 1.9 - 2.0. Due to the difference in refractive index, the propagation direction of the light ray emitted from the optical coupling layer 103 changes, and the light ray with a larger exit angle can be redirected to the front direction of the display substrate, which is more conducive to the light rays converging towards the front direction of the display substrate. In this way, the light rays emitted from the side of the display substrate can be reduced, the light extraction efficiency of the display substrate can be improved, thereby improving the display effect and further enhancing the user experience.

[0059] Figure 5 This is a schematic structural diagram of another display substrate provided by an embodiment of the present disclosure. As Figure 5 shown, the display substrate further includes: a temperature adjustment layer 108; the temperature adjustment layer 108 is located on the side of the photorefractive crystal layer 105 close to the optical coupling layer 103.

[0060] The temperature adjustment layer 108 can be made of heating wires, such as alloy materials like iron-chromium-aluminum and nickel-chromium. Under the control of voltage, the temperature adjustment layer 108 can generate a relatively high temperature. By controlling the temperature of the temperature adjustment layer 108, the refractive index of the photorefractive crystal layer 105 can be adjusted so that the refractive index of the photorefractive crystal layer 105 is between that of the optical coupling layer 103 and the encapsulation layer 104. According to Snell's law \(n 1 \sin\theta 1 = n 2 \sin\theta 2 (n 1 and \(n 2 are the refractive indices of adjacent different film layers, and \(\theta 1 and \(\theta 2 are the angles between the light ray and the normal at the interfaces of adjacent different film layers), the refractive index can be effectively determined. For example, the refractive index of the photorefractive crystal layer 105 can be controlled to be around 1.9 - 2.0. Due to the difference in refractive index, the propagation direction of the light ray emitted from the optical coupling layer 103 changes. The light ray with a larger exit angle can be redirected to the front direction of the display substrate, which is more conducive to the convergence of light rays towards the front direction of the display substrate. In this way, the light ray exiting from the side of the display substrate can be reduced, the light extraction efficiency of the display substrate can be improved, thereby improving the display effect and further enhancing the user experience.

[0061] In some embodiments, the photorefractive crystal layer 105 includes: a plurality of nanoparticles 1051 arranged in an array; the orthographic projection of the nanoparticles 1051 on the substrate 101 at least partially overlaps with the orthographic projection of the light-emitting device 102 on the substrate 101.

[0062] The photorefractive crystal layer 105 can be divided into a plurality of nanoparticles 1051 arranged in an array (as specifically shown in Figure 6 ), and the nanoparticles 1051 can be correspondingly arranged for different regions of the light-emitting device 102 or each light-emitting device 102. The refractive indices of the light rays emitted by different light-emitting devices 102 in the same medium are also different. Since the nanoparticles 1051 are isolated from each other, the refractive indices of different nanoparticles 1051 can be independently adjusted, so that the refractive indices of the nanoparticles 1051 in different regions of different photorefractive crystal layers 105 are different, meeting the requirement of independent adjustment of light rays in different regions of the display substrate, further improving the display effect of the display substrate and enhancing the user experience.

[0063] Second aspect, embodiments of the present disclosure provide a display device, which includes a display substrate provided in any of the above embodiments. Specifically, the display device may be a device such as a mobile phone, a laptop computer, a tablet computer, a smart TV, a vehicle-mounted display screen, etc. Other essential components of the display device are understood by those of ordinary skill in the art and will not be elaborated herein, nor should they be regarded as a limitation to the present disclosure. Its implementation principle and beneficial effects are similar to those of the display substrate provided in any of the above embodiments and will not be described in detail herein.

[0064] Third aspect, embodiments of the present disclosure provide a method for manufacturing a display substrate, which is used to manufacture the display substrate provided in any of the above embodiments. Figure 7 As shown in the flowchart of a method for manufacturing a display substrate provided in an embodiment of the present disclosure, as Figure 7 shown, the method for manufacturing the display substrate includes the following steps S701 to S705.

[0065] S701, successively form a plurality of light-emitting devices and an optical coupling layer on a substrate.

[0066] In the above step S701, film layers such as the anode 1021, the organic light-emitting layer 1023, and the cathode 1022 of the light-emitting device 102 are successively formed on the substrate 101. Before forming each film layer of the above light-emitting device 102, a driving circuit layer, a pixel defining layer, etc. also need to be formed. A high-performance organic material such as cycloolefin polymer is deposited on the cathode 1022 of the formed light-emitting device 102 to form an optical coupling layer 103.

[0067] S702, mount a photorefractive crystal on a support substrate and process the photorefractive crystal to form a photorefractive crystal layer.

[0068] S703, peel the photorefractive crystal layer from the support substrate.

[0069] In the above steps S702 to S703, the photorefractive crystal layer 105 can be made of a photorefractive crystal with an adjustable refractive index, such as at least one of lithium niobate crystal, potassium dihydrogen phosphate crystal, low-temperature phase barium metaborate crystal, rubidium titanyl phosphate crystal, and lanthanum gallium silicate crystal. In the embodiments of the present disclosure, lithium niobate crystal will be taken as an example for illustration.

[0070] When the lithium niobate crystal is mounted on the support substrate, then helium ions are vertically implanted into the lithium niobate crystal, and then the ion-implanted lithium niobate crystal is placed in diluted hydrofluoric acid for etching, and the surface layer of the lithium niobate crystal will be peeled off to form a photorefractive crystal layer 105.

[0071] S704, attach the photorefractive crystal layer to the optical coupling layer.

[0072] In S705, an encapsulation layer is formed on the photorefractive crystal layer.

[0073] In the above steps S704 to S705, the photorefractive crystal layer 105 can be attached to the optical coupling layer 103, and an encapsulation layer 104 is formed on the photorefractive crystal layer 105, such that the photorefractive crystal layer 105 is located between the optical coupling layer 103 and the encapsulation layer 104. The refractive index of the photorefractive crystal layer 105 can be adjusted such that the refractive index of the photorefractive crystal layer 105 is between that of the optical coupling layer 103 and the encapsulation layer 104. According to Snell's law \(n_1\sin\theta_1 = n_2\sin\theta_2\) (where \(n_1\) and \(n_2\) are the refractive indices of adjacent different film layers, and \(\theta_1\) and \(\theta_2\) are the angles between the light ray and the normal at the interface of adjacent different film layers), its refractive index can be effectively determined. For example, the refractive index of the photorefractive crystal layer 105 can be controlled to be around 1.9 - 2.0. Due to the difference in refractive index, the propagation direction of the light ray emitted from the optical coupling layer 103 changes. The light ray with a larger exit angle can be redirected to the front direction of the display substrate, which is more conducive to the convergence of light towards the front direction of the display substrate. In this way, the light ray emitted from the side of the display substrate can be reduced, the light extraction efficiency of the display substrate can be improved, thereby improving the display effect and further enhancing the user experience. 1 sinθ 1 = n 2 sinθ 2 (n 1 、n 2 are the refractive indices of adjacent different film layers, θ 1 、θ 2 are the angles between the light ray and the normal at the interface of adjacent different film layers), its refractive index can be effectively determined. For example, the refractive index of the photorefractive crystal layer 105 can be controlled to be around 1.9 - 2.0. Due to the difference in refractive index, the propagation direction of the light ray emitted from the optical coupling layer 103 changes. The light ray with a larger exit angle can be redirected to the front direction of the display substrate, which is more conducive to the convergence of light towards the front direction of the display substrate. In this way, the light ray emitted from the side of the display substrate can be reduced, the light extraction efficiency of the display substrate can be improved, thereby improving the display effect and further enhancing the user experience.

[0074] In some embodiments, as Figure 7 shown, for the above step S703 of peeling the photorefractive crystal layer from the support substrate, it further includes: step S703A of inducing the photorefractive crystal layer through a specific chemical reaction in a physical process, or performing a chemical reaction under the conditions in a physical process, such that the photorefractive crystal layer forms a plurality of nanoparticles arranged in an array.

[0075] In the above step S703A, the photorefractive crystal layer is induced by a specific chemical reaction during a physical process, or a chemical reaction is carried out under the conditions of a physical process, and the entire photorefractive crystal layer 105 is divided into a plurality of nanoparticles 1051 arranged in an array. The nanoparticles 1051 can be correspondingly arranged with the light-emitting devices 102 in different regions or each light-emitting device 102. The refractive indices of the light rays emitted by different light-emitting devices 102 in the same medium are also different. Since the nanoparticles 1051 are isolated from each other, the refractive indices of different nanoparticles 1051 can be independently adjusted, so that the refractive indices of the nanoparticles 1051 in different regions of different photorefractive crystal layers 105 are different, meeting the requirement that the light rays in different regions of the display substrate need to be independently adjusted, further improving the display effect of the display substrate and enhancing the user experience.

[0076] It should be noted that in the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. Also, it can be understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be an intermediate layer. Additionally, it can be understood that when an element or layer is referred to as being "under" another element or layer, it can be directly under the other element, or there may be more than one intermediate layer or element. Further, it can be understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Like reference numerals throughout the specification indicate like elements.

[0077] In several embodiments provided by the present disclosure, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the positions of the components shown are only for a logical functional position, and there may be other position arrangements in actual implementation.

[0078] In the embodiments of the present disclosure, the descriptions with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this specification. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0079] It is understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present disclosure. However, the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.

Claims

1. A display substrate, characterized in that: The display substrate comprises: a base substrate, a plurality of light emitting devices on the base substrate, an optical coupling layer located on a side of the light emitting devices away from the base substrate, and an encapsulation layer located on a side of the optical coupling layer away from the base substrate; the display substrate further comprises: a photorefractive crystal layer located between the optical coupling layer and the encapsulation layer; The refractive index of the photorefractive crystal layer is adjustable and is between the refractive index of the optical coupling layer and the refractive index of the packaging layer.

2. The display substrate according to claim 1, characterized in that: The display substrate further includes: a first electrode and a second electrode; The first electrode and the second electrode are arranged at intervals and are both located on a side of the photorefractive crystal layer close to the optical coupling layer.

3. The display substrate according to claim 1, characterized in that: The display substrate further includes: a first electrode and a second electrode; The first electrode is located on a side of the photorefractive crystal layer close to the optical coupling layer; The second electrode is located on a side of the photorefractive crystal layer close to the packaging layer.

4. The display substrate according to claim 1, characterized in that: The display substrate further includes: a temperature adjustment layer; The temperature adjustment layer is located on a side of the photorefractive crystal layer close to the optical coupling layer.

5. The display substrate according to claim 1, characterized in that: The material of the photorefractive crystal layer includes at least one of lithium niobate crystal, potassium dideuterium phosphate crystal, low temperature phase barium metaborate crystal, rubidium titanyl phosphate crystal and lanthanum gallium silicate crystal.

6. The display substrate according to claim 1, characterized in that: The photorefractive crystal layer comprises: a plurality of nanoparticles arranged in an array; The orthographic projection of the nanoparticles on the substrate at least partially overlaps with the orthographic projection of the light-emitting device on the substrate.

7. The display substrate according to claim 6, characterized in that: The light emitting devices include: a red light emitting device, a green light emitting device and a blue light emitting device.

8. A display device, characterized in that: The display device comprises the display substrate according to any one of claims 1 to 7.

9. A method for preparing a display substrate, for preparing the display substrate according to any one of claims 1 to 7, characterized in that: The method for preparing the display substrate comprises: forming a plurality of light emitting devices and an optical coupling layer in sequence on a substrate; Mounting a photorefractive crystal on a supporting substrate and processing the photorefractive crystal to form a photorefractive crystal layer; peeling the photorefractive crystal layer from the supporting substrate; Attaching the photorefractive crystal layer to the optical coupling layer; A packaging layer is formed on the photorefractive crystal layer.

10. The method for preparing a display substrate according to claim 9, characterized in that: The photorefractive crystal layer is peeled off from the supporting substrate, before which the method further comprises: The photorefractive crystal layer is induced in a physical process through a specific chemical reaction, or a chemical reaction is carried out under the conditions of a physical process, so that the photorefractive crystal layer forms a plurality of nanoparticles arranged in a plurality of arrays.

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