Display substrate, preparation method thereof and display device

Abstract

The present disclosure provides a display substrate and a manufacturing method thereof, and a display device. The display substrate includes a plurality of sub-pixel units arranged in an array on a base layer, and each sub-pixel unit includes a light propagation unit located on one side of a light-emitting unit. The light propagation unit includes a first dielectric structure and a second dielectric structure. A projection of the first dielectric structure at least partially overlaps with a projection of the light-emitting unit. The second dielectric structure is in contact with the first dielectric structure on at least one side in a direction parallel to a plane in which the base layer is located. A first refractive index of the first dielectric structure is greater than a second refractive index of the second dielectric structure. A first included angle between a diagonal line and a bottom side of a first cross section of the first dielectric structure is equal to a total reflection angle of a contact surface between the first dielectric structure and the second dielectric structure. The first included angle is less than or equal to a preset angle, so that more than or equal to a preset proportion of light rays among light rays incident from a bottom surface of the first dielectric structure can be emitted from a top surface of the first dielectric structure.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display substrate, its preparation method, and a display device. Background Technology

[0002] Quantum dot organic light-emitting diode (QD-OLED) devices are considered the next generation of display solutions due to their excellent color gamut performance and good color display capabilities. This solution uses blue OLED as a backlight to excite photochromic quantum dot (QD) particles to obtain different red and green lights. Summary of the Invention

[0003] This disclosure provides a display substrate, a method for preparing the same, and a display device.

[0004] According to a first aspect of this disclosure, a display substrate is provided, the display substrate comprising a substrate layer and a plurality of sub-pixel units arranged in an array on one side of the substrate layer, each sub-pixel unit corresponding to a light-emitting unit, and at least a portion of the plurality of sub-pixel units constituting a pixel unit; characterized in that, the sub-pixel unit further comprises a light propagation unit located on one side of the light-emitting surface of the light-emitting unit; the light propagation unit comprises a first dielectric structure and a second dielectric structure, the orthographic projection of the first dielectric structure on the substrate layer at least partially overlapping the orthographic projection of a light-emitting unit on the substrate layer, and the second dielectric structure and the first dielectric structure being contacted on at least one side in a direction parallel to the plane of the substrate layer; The first dielectric structure has a first refractive index, and the second dielectric structure has a second refractive index, wherein the first refractive index is greater than the second refractive index; the first included angle between the diagonal of the first cross-section of the first dielectric structure and its base is equal to the total internal reflection angle of the contact surface between the first dielectric structure and the second dielectric structure, wherein the first cross-section is a cross-section of the first dielectric structure along a direction perpendicular to the contact surface and perpendicular to the light-emitting surface; the first included angle is less than or equal to a preset angle, such that among the light rays incident from the first dielectric structure toward the bottom surface of the light-emitting unit at any angle, light rays greater than or equal to a preset proportion of light rays can all exit from the first dielectric structure toward the top surface of the light-emitting unit, wherein the preset angle is 60°.

[0005] In some embodiments, the angle of the first included angle ranges from 10° to 40°.

[0006] In some embodiments, the height and width of the first cross-section of the first medium structure satisfy the following relationship: Where a is the height of the first cross section of the first dielectric structure, L is the width of the first cross section of the first dielectric structure, θ1 is the first included angle, and θ2 is the second included angle between the contact surface of the second dielectric structure with the first dielectric structure and the bottom surface facing the light-emitting unit.

[0007] In some embodiments, the angle of the second included angle ranges from 10° to 90°.

[0008] In some embodiments, the angle of the second included angle ranges from 50° to 90°.

[0009] In some embodiments, the height of the first cross section ranges from 2 micrometers to 20 micrometers.

[0010] In some embodiments, the sub-pixel unit further includes a light conversion unit located on the side of the first dielectric structure away from the light-emitting unit; the orthographic projection of the light conversion unit on the substrate layer at least partially overlaps with the orthographic projection of the light-emitting unit on the substrate layer; and the orthographic projection of the light conversion unit on the substrate layer at least partially overlaps with the orthographic projection of the first dielectric structure on the substrate layer; the light conversion unit is used to convert the emission color of the light-emitting unit into a target emission color.

[0011] In some embodiments, the light conversion unit includes a quantum dot structure.

[0012] In some embodiments, the ratio of the second refractive index to the first refractive index ranges from 0.5 to 0.9.

[0013] In some embodiments, the orthographic projection of the first dielectric structure onto the plane where the light-emitting surface is located overlaps the orthographic projection of the light-emitting unit onto the plane where the light-emitting surface is located.

[0014] In some embodiments, the shape of the first cross section of the first dielectric structure is rectangular, and the shape of the cross section of the second dielectric structure along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface is rectangular; or, the shape of the first cross section of the first dielectric structure is an inverted trapezoid, and the shape of the cross section of the second dielectric structure along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface is trapezoidal.

[0015] In some embodiments, the second medium structure is disposed between two adjacent first medium structures, and the light emission colors of the sub-pixel units corresponding to the two adjacent first medium structures are different.

[0016] In some embodiments, the orthographic projection of the light conversion unit on the substrate layer overlaps the orthographic projection of its corresponding light-emitting unit on the substrate layer.

[0017] In some embodiments, the material of the second medium structure is a siloxane material doped with hollow particles.

[0018] In some embodiments, the plurality of sub-pixel units include red sub-pixel units, green sub-pixel units, and blue sub-pixel units, and the light-emitting units corresponding to the plurality of sub-pixel units emit light in blue.

[0019] In some embodiments, each pixel unit includes three sub-pixel units, namely a first sub-pixel unit, a second sub-pixel unit, and a third sub-pixel unit; the light emission color of the light-emitting units corresponding to the plurality of sub-pixel units is a first light emission color; the first sub-pixel unit includes a first light conversion unit, the second sub-pixel unit includes a second light conversion unit, and the third sub-pixel unit includes a light-transmitting unit; the first light conversion unit is used to convert the first light emission color of the corresponding light-emitting unit into a second light emission color; the second light conversion unit is used to convert the first light emission color of the corresponding light-emitting unit into a third light emission color; and the light-transmitting unit is used to transmit light emitted by the corresponding light-emitting unit without changing the first light emission color.

[0020] In some embodiments, the first emitting color is blue, the second emitting color is red, and the third emitting color is green.

[0021] According to a second aspect of this disclosure, a display device is provided, the display device including the display substrate described above.

[0022] According to a third aspect of this disclosure, a method for fabricating a display substrate is provided. The method includes: providing a substrate layer; forming a plurality of light-emitting units arranged in an array on one side of the substrate layer, each light-emitting unit corresponding to a sub-pixel unit, and at least a portion of the plurality of sub-pixel units constituting a pixel unit; forming a light-propagating unit on the side of each light-emitting unit away from the substrate layer, the light-propagating unit including a first dielectric structure and a second dielectric structure, wherein the orthographic projection of the first dielectric structure onto the substrate layer at least partially overlaps with the orthographic projection of one of the light-emitting units onto the substrate layer, and the second dielectric structure is in contact with the first dielectric structure on at least one side in a direction parallel to the plane of the substrate layer. The first dielectric structure has a first refractive index, and the second dielectric structure has a second refractive index, wherein the first refractive index is greater than the second refractive index; wherein, the first included angle between the diagonal of the first cross-section of the first dielectric structure and the bottom edge is equal to the total internal reflection angle of the contact surface between the first dielectric structure and the second dielectric structure, and the first cross-section is the cross-section of the first dielectric structure along a direction perpendicular to the contact surface and perpendicular to the light-emitting surface; the first included angle is less than or equal to a preset angle, such that among the light rays incident from the first dielectric structure toward the bottom surface of the light-emitting unit at any angle, light rays greater than or equal to a preset proportion of light rays are emitted from the first dielectric structure toward the top surface of the light-emitting unit, and the preset angle is 60°. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0024] Figure 1a This is a schematic diagram of the structure of a sub-pixel unit provided in an embodiment of the present disclosure.

[0025] Figure 1b This is a planar schematic diagram of a sub-pixel unit provided in an embodiment of the present disclosure.

[0026] Figure 2 This is a schematic diagram of another sub-pixel unit provided in an embodiment of this disclosure.

[0027] Figure 3 This is a schematic diagram of the light intensity distribution curve in a specific embodiment where the first included angle θ1 is in the range of 10° to 60°.

[0028] Figure 4 This is a schematic diagram showing the proportion of light rays that can be effectively utilized at different angles, where the first included angle θ1 is θ1.

[0029] Figure 5This is a schematic diagram showing light rays incident from the bottom surface of the first dielectric structure to the contact surface between the first dielectric structure and the second dielectric structure.

[0030] Figure 6 This is a schematic diagram of the structure of another sub-pixel unit provided in an embodiment of the present disclosure.

[0031] Figure 7 This is a schematic diagram of another sub-pixel unit provided in an embodiment of the present disclosure.

[0032] Figure 8 This is a planar schematic diagram of a display substrate provided in an embodiment of the present disclosure.

[0033] Figure 9 This is a schematic diagram of the structure of a display substrate provided in an embodiment of this disclosure.

[0034] Figure 10 This is a schematic diagram of the structure of the light-emitting unit of the sub-pixel unit in an embodiment of this disclosure;

[0035] Figure 11 This is a flowchart illustrating a method for fabricating a sub-pixel unit according to an embodiment of this disclosure.

[0036] Figure 12 This is a flowchart illustrating a method for fabricating a display substrate according to an embodiment of the present disclosure. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of the embodiments of this disclosure, the technical solutions of the display substrate and its preparation method and display device provided in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings.

[0038] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “including” are used in this specification, the presence of the said feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0040] It will be understood that while this document may use the terms first, second, etc., to describe various elements / structures, these elements / structures should not be limited to these terms. These terms are only used to distinguish one element / structure from another.

[0041] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0042] In related technologies, in QD-OLED devices, since OLED is a surface light source, if the emitted light cannot be focused and collimated, it will affect the QD particles' ability to effectively utilize OLED light.

[0043] In view of this, embodiments of the present disclosure provide a sub-pixel unit, Figure 1a This is a schematic diagram of the structure of a sub-pixel unit provided in an embodiment of the present disclosure. Figure 1b This is a planar schematic diagram of a sub-pixel unit provided in an embodiment of the present disclosure, such as... Figure 1a and Figure 1b As shown, the sub-pixel unit includes: a substrate layer 21, a light-emitting unit 11 located on one side of the substrate layer 21, and a light-propagating unit 12 located on one side of the light-emitting surface of the light-emitting unit 11. The light-propagating unit 12 includes a first dielectric structure 121 and a second dielectric structure 122. The orthographic projection of the first dielectric structure 121 on the substrate layer 21 at least partially overlaps with the orthographic projection of the light-emitting unit 11 on the substrate layer 21. The second dielectric structure 122 is in contact with the first dielectric structure 121 on at least one side in a direction parallel to the plane of the substrate layer 21. The first dielectric structure 121 has a first refractive index n1, and the second dielectric structure 122 has a second refractive index n2. The first refractive index n1 is greater than the second refractive index n2.

[0044] In one specific embodiment, such as Figure 1bAs shown, the second dielectric structure 122 is disposed around the first dielectric structure 121, and the side of the second dielectric structure 122 facing the first dielectric structure 121 directly contacts the four sides of the first dielectric structure 121. These four sides of the first dielectric structure 121 are referred to as the contact surfaces between the first dielectric structure 121 and the second dielectric structure 122 in this embodiment. Optionally, the second dielectric structure 122 may also contact the first dielectric structure 121 only on one or more sides. For example, color crosstalk between sub-pixels of different colors causes a stronger visual effect, while color crosstalk between sub-pixels of the same color is relatively difficult to detect. Therefore, to reduce process complexity, the second dielectric structure 122 can be disposed only between the first dielectric structures 121 corresponding to two adjacent sub-pixels of different colors. For example, the first dielectric structures 121 corresponding to adjacent sub-pixels of the same color can be filled with the same material as the first dielectric structure 121 (or fabricated in a single process with the first dielectric structure 121).

[0045] In this embodiment, the first medium structure 121 is an optically denser medium, and the second medium structure 122 is an optically less dense medium. According to the principle of total internal reflection (TIR), when light enters a medium with a lower refractive index (also called an optically denser medium) from a medium with a higher refractive index, when the angle of incidence is greater than or equal to the angle of total internal reflection (also called the critical angle) θc, i.e., when the incident ray is far from the normal, the refracted ray will disappear, and all incident rays will be reflected and will not enter the medium with the lower refractive index. When the angle of incidence is less than the angle of total internal reflection θc, the light simultaneously refracts into the medium with the lower refractive index and reflects into the medium with the higher refractive index.

[0046] According to the definition of total internal reflection, the condition for total internal reflection to occur at the contact surface between the first dielectric structure 121 and the second dielectric structure 122 is: θ≥arcsin(n2 / n1), where θ is the angle between the incident ray and the normal to the contact surface, n2 is the second refractive index of the second dielectric structure 122, n1 is the first refractive index of the first dielectric structure 121, and arcsin(n2 / n1) refers to the total internal reflection angle of the contact surface.

[0047] Therefore, the light emitted by the light-emitting unit 11 enters the first dielectric structure 121 through the bottom surface of the first dielectric structure 121 facing the light-emitting unit 11. When the light incident from the bottom surface of the first dielectric structure 121 irradiates the contact surface between the first dielectric structure 121 and the second dielectric structure 122, and the incident angle of the light is greater than or equal to the total internal reflection angle of the contact surface between the first dielectric structure 121 and the second dielectric structure 122, i.e., arcsin(n2 / n1), the light will undergo total internal reflection at the contact surface between the first dielectric structure 121 and the second dielectric structure 122.

[0048] For all light rays incident from the bottom surface of the first medium structure 121 toward the light-emitting unit 11, any light ray incident at an angle of incidence greater than or equal to the total reflection angle will undergo total reflection when it hits the contact surface, thereby effectively improving the focusing effect of the light emitted by the light-emitting unit 11 and thus improving the light utilization rate of the light-emitting unit 11.

[0049] In this embodiment of the disclosure, in practical applications, the light-emitting unit 11 can be an organic light-emitting diode (OLED), such as a blue organic light-emitting diode. By setting the light propagation unit 12, the light-gathering effect of the light emitted by the light-emitting unit 11 can be effectively improved, thereby effectively improving the luminous efficiency of the light-emitting unit 11. In practical applications, the sub-pixel unit can be applied to QD-OLED devices, which can effectively improve the utilization effect of QD particles on the light emitted by the light-emitting unit 11.

[0050] It should be noted that, Figure 1a yes Figure 1b The diagram shows a longitudinal section of a sub-pixel unit along the AA' direction or the BB' direction.

[0051] In the embodiments disclosed herein, such as Figure 1a and Figure 1bAs shown, the first included angle θ1 between the diagonal of the first cross section of the first dielectric structure 121 and the bottom edge is equal to the total reflection angle of the contact surface between the first dielectric structure 121 and the second dielectric structure 122, that is, the first included angle θ1 is equal to arcsin(n2 / n1). The first cross section is the longitudinal cross section of the first dielectric structure 121 along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface of the light-emitting unit 11 (i.e., the AA' direction or the BB' direction). With this configuration, total internal reflection can occur when light is incident at an angle greater than or equal to the first included angle θ1 onto the contact surface of the first dielectric structure 121 and the second dielectric structure 122. This ensures that the incident angle of light from the bottom surface of the first dielectric structure 121 to the top surface of the contact surface is greater than or equal to the first included angle θ1, resulting in total internal reflection. On the one hand, this further improves the light-gathering effect of the light emitted by the light-emitting unit 11 and enhances the luminous efficiency of the light-emitting unit 11. On the other hand, in practical applications, it can effectively avoid light emission crosstalk between adjacent sub-pixels and further improve the utilization effect of QD particles on the light emitted by the light-emitting unit 11.

[0052] It should be noted that, in the embodiments of this disclosure, when the contact surface between the first medium structure 121 and the second medium structure 122 is arc-shaped, the direction perpendicular to the contact surface can be understood as a tangential direction perpendicular to the contact surface.

[0053] Since the first included angle θ1 is equal to the total internal reflection angle of the contact surface between the first dielectric structure 121 and the second dielectric structure 122, the smaller the first included angle θ1, the more light can be totally reflected by the contact surface. This means more light can undergo total internal reflection, resulting in better light focusing in the first dielectric structure 121 and higher luminous efficiency of the light-emitting unit 11. In practical applications, this translates to more effectively utilized OLED light intensity and better utilization of the light emitted by the QD particles. Therefore, by adjusting the first included angle θ1, the proportion of effectively utilized light emitted by the light-emitting unit 11 and incident from the first dielectric structure 121 towards the bottom surface of the light-emitting unit 11 can be adjusted.

[0054] In the embodiments disclosed herein, such as Figure 1a As shown, the first included angle θ1 can be set to be less than or equal to a preset angle so that among the light rays incident from the first dielectric structure 121 toward the bottom surface of the light-emitting unit 11 at any angle, light rays greater than or equal to a preset light ratio can all be emitted from the first dielectric structure 121 toward the top surface of the light-emitting unit 11, that is, light rays greater than or equal to a preset light ratio can all be effectively utilized.

[0055] In some embodiments, the preset angle can be set to 60°, and the angle range of the first included angle θ1 can be less than or equal to 60°. For example, the angle of the first included angle θ1 can be taken in the range of 10° to 60°. When the first included angle θ1 is less than or equal to 60°, light can be effectively utilized, while the color crosstalk caused to adjacent pixels is relatively small.

[0056] In some embodiments, the ratio of the second refractive index n2 to the first refractive index n1 ranges from 0.5 to 0.9, which can ensure that light rays greater than or equal to a preset light ratio can be effectively utilized.

[0057] In some embodiments, the first included angle θ1 can be in the range of 10° to 40°, for example, the first included angle θ1 can be set to 40°. When the first included angle θ1 is between 10° and 40°, a larger proportion of the light can be effectively utilized.

[0058] In some embodiments, the orthographic projection of the first dielectric structure 121 on the substrate 21 coincides with the orthographic projection of the light-emitting unit 11 on the substrate 21, or the orthographic projection of the first dielectric structure 121 on the substrate 21 covers the orthographic projection of the light-emitting unit 11 on the substrate 21. This structural design can make full use of the light emitted by the light-emitting unit 11 and improve the light extraction efficiency of the display substrate.

[0059] It should be noted that when the orthographic projection of the first dielectric structure 121 on the substrate 21 covers the orthographic projection of the light-emitting unit 11 on the substrate 21, the design can still be carried out with the first included angle θ1 between the diagonal of the first cross-section of the first dielectric structure 121 and the bottom edge being less than or equal to 60°. It is understood that when the orthographic projection of the first dielectric structure 121 on the substrate 21 covers the orthographic projection of the light-emitting unit 11 on the substrate 21, compared to the cases where the orthographic projection of the first dielectric structure 121 on the substrate 21 coincides with the orthographic projection of the light-emitting unit 11 on the substrate 21, or where the orthographic projection of the light-emitting unit 11 on the substrate 21 covers the orthographic projection of the first dielectric structure 121 on the substrate 21, the proportion of light not totally reflected by the contact surface between the first dielectric structure 121 and the second dielectric structure 122 on the opposite side of the vertex of the first included angle θ1 is lower, thus achieving a better effect in preventing color crosstalk.

[0060] In some embodiments, the light-emitting unit 11 may also include an encapsulation structure between it and the first dielectric structure 121, for example, by encapsulating the light-emitting unit 11 in the form of a three-layer encapsulation sub-layer of inorganic layer-organic layer-inorganic layer to prevent the light-emitting unit 11 from being corroded by water and oxygen.

[0061] In some embodiments, such as Figure 1aAs shown, the height a and width L of the first cross section of the first medium structure 121 satisfy the following relationship:

[0062] Where a is the height of the first cross section of the first dielectric structure 121, L is the width of the first cross section of the first dielectric structure 121, θ1 is the first included angle, and θ2 is the second included angle between the contact surface of the second dielectric structure 122 with the first dielectric structure 121 and the bottom surface facing the light-emitting unit 11.

[0063] The second included angle θ2 ranges from 10° to 90°. In some embodiments, the second included angle θ2 ranges from 50° to 90°. In some embodiments, the second included angle θ2 is 90°. In some embodiments, the second included angle θ2 is less than 90°.

[0064] In some embodiments, the first cross-section of the first dielectric structure 121 is inverted trapezoidal, and the longitudinal cross-section of the second dielectric structure 122 along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface of the light-emitting unit 11 (i.e., the AA' direction or the BB' direction) is trapezoidal. Here, an inverted trapezoid refers to a shape where the upper width is greater than the lower width.

[0065] It should be noted that, Figure 1a The illustration only shows an example where the first cross-section of the first dielectric structure 121 is inverted trapezoidal and the longitudinal cross-section of the second dielectric structure 122 is trapezoidal; however, embodiments of this disclosure include, but are not limited to, this. Figure 2 This is a schematic diagram of another sub-pixel unit structure provided in an embodiment of the present disclosure. In some embodiments, such as... Figure 2 As shown, the first cross-section of the first dielectric structure 121 is rectangular, and the longitudinal cross-section of the second dielectric structure 122 along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface of the light-emitting unit 11 (i.e., the AA' direction or the BB' direction) is rectangular.

[0066] In some embodiments, the height 'a' of the first cross section ranges from 2 micrometers to 20 micrometers.

[0067] In some embodiments, the sub-pixel units are applied to a display substrate, which includes a plurality of sub-pixel units arranged in an array, wherein the width of the first cross section of the first dielectric structure 121 in each sub-pixel unit is equal to the pixel width corresponding to the pixel resolution of the display substrate.

[0068] The following are respectively based on Figure 1a The sub-pixel units shown and Figure 2 Taking the sub-pixel unit shown as an example, the relationship between the height a, width L, first included angle θ1, and second included angle θ2 of the first cross section of the first medium structure 121 will be explained in detail.

[0069] When the first cross-section of the first medium structure 121 is rectangular and the longitudinal cross-section of the second medium structure 122 is rectangular, such as Figure 2 As shown, a ray enters the first dielectric structure 121 at an angle θ between itself and the bottom surface of the first dielectric structure 121, and is incident on the contact surface between the first dielectric structure 121 and the second dielectric structure 122. At this time, the angle between the ray and the normal to the contact surface is angle θ. When the ray is incident along the diagonal of the first cross-section of the first dielectric structure 121, the angle θ is the first angle θ1. At this time, the relationship between the height a, width L, first angle θ1, and second angle θ2 of the first cross-section of the first dielectric structure 121 is: tanθ1=a / L.

[0070] Figure 3 This is a schematic diagram of the light intensity distribution curve of the first included angle θ1 in the range of 10° to 60° in a specific embodiment. Based on the experimental test data of the light intensity of the light-emitting unit 11 (such as a blue OLED) under different first included angle θ1 conditions, the relationship between the first included angle θ1 and the light intensity can be determined. The light intensity distribution curve of the first included angle θ1 in the range of 10° to 60° is shown below. Figure 3 As shown.

[0071] Based on the relationship between the first included angle θ1 and the light intensity, when the first included angle is θ1, the brightness distribution curve corresponding to the range of θ1 to 60° is integrated and recorded as the first integral, and the brightness distribution curve corresponding to the range of 10° to 60° is integrated and recorded as the second integral. The ratio of the first integral to the second integral can be used to determine the proportion of light that can be effectively utilized at different angles of the first included angle θ1.

[0072] Table 1

[0073]

[0074]

[0075] Figure 4 This diagram illustrates the proportion of light rays that can be effectively utilized at different angles with the first included angle θ1. Table 1 shows the results of theoretical tests on the proportion of light rays that can be effectively utilized at different angles with the first included angle θ1. Figure 4As shown, when the first included angle θ1 is 10°, light rays incident at an angle greater than or equal to 10° (the angle between the incident ray and the bottom surface of the first dielectric structure 121) will undergo total internal reflection at the contact surface between the first dielectric structure 121 and the second dielectric structure 122. That is, light rays at almost all incident angles will undergo total internal reflection at the contact surface. Based on the integration ratio, it can be determined that the proportion of usable light rays can be as high as 100%. When the first included angle θ1 is 40°, light rays incident at an angle greater than or equal to 40° (the angle between the incident ray and the bottom surface of the first dielectric structure 121) will undergo total internal reflection at the contact surface between the first dielectric structure 121 and the second dielectric structure 122. That is, light rays at almost most incident angles will undergo total internal reflection at the contact surface. Based on the integration ratio, it can be determined that the proportion of usable light rays can be as high as 90%.

[0076] As shown in the table above, the smaller the value of the first included angle θ1, the more light intensity of the light-emitting unit 11 can be effectively utilized. It is generally believed that 90% of the light is utilized, and the crosstalk of light to adjacent sub-pixels can be ignored. Therefore, as shown in the table above, when the first included angle θ1 = 40°, that is, the total reflection angle is 40°, and the angle range of the first included angle θ1 is 10° to 40°, the light utilization effect is better, and the utilization rate is as high as 90% or more.

[0077] For example, when the preset angle is 60°, the preset light ratio can be the light ratio corresponding to the first included angle θ1 being 60° in Table 1, which is 74%.

[0078] In practical applications, the width of the first cross-section of the first dielectric structure 121 in the sub-pixel unit can be defined as the pixel width corresponding to the pixel resolution of the display substrate. When the pixel resolution is 600 PPI, the pixel width should be 42 μm. When the first included angle θ1 = 40°, according to the above formula tanθ1 = a / L, where L is the pixel width, i.e., the width of the first cross-section, the height (thickness) of the first dielectric structure 121 and the second dielectric structure 122 should be a = L * tanθ1, i.e., a = 34 μm. When the pixel resolution is 300 PPI, the pixel width should be 84 μm. When the first included angle θ1 = 40°, according to the above formula tanθ1 = a / L, where L is the pixel width, the height (thickness) of the first medium structure 121 and the second medium structure 122 should be a = L * tanθ1, that is, a = 70um; when the pixel resolution is 160 PPI, the pixel width should be 159um. When the first included angle θ1 = 40°, according to the above formula tanθ1 = a / L, where L is the pixel width, the height (thickness) of the first medium structure 121 and the second medium structure 122 should be a = L * tanθ1, that is, a = 131um.

[0079] In such Figure 2In the sub-pixel unit shown, the amount of light that can be used mainly depends on the refractive index ratio between the second medium structure 122 and the first medium structure 121, that is, on the size of the first included angle θ1.

[0080] To further improve the utilization of light, in some embodiments, the shape of the first cross section of the first medium structure 121 is set to an inverted trapezoid, and the shape of the longitudinal cross section of the second medium structure 122 is set to a trapezoid. Figure 5 This is a schematic diagram showing light incident from the bottom surface of the first dielectric structure to the contact surface between the first and second dielectric structures. When the first cross-section is rectangular, the contact surface between the first dielectric structure 121 and the second dielectric structure 122 is a perpendicular surface (perpendicular to the bottom surface). When the shape of the first cross-section of the first dielectric structure 121 is an inverted trapezoid, and the shape of the longitudinal cross-section of the second dielectric structure 122 is a trapezoid, the contact surface between the first dielectric structure 121 and the second dielectric structure 122 is an inclined surface (inclined relative to the normal to the bottom surface). Figure 1a and Figure 5 As shown, assuming the incident angle of the incident ray is θ1, the reflection angle of the ray on the vertical plane, i.e., the first included angle, should be θ1, and the reflection angle on the inclined plane should be θ. Simultaneously, let the angle between the inclined plane and the base plane, i.e., the second included angle, be θ2. According to geometric relationships, if the incident angle of the ray remains constant at θ1, then its reflection angle on the inclined plane is θ = θ1 + 90° - θ2. When the contact surface is a vertical plane, the reflection angle θ of the ray on the vertical plane is θ1. When the contact surface is an inclined plane, the reflection angle θ of the ray on the inclined plane changes, increasing from the previous θ1 by 90° - θ2.

[0081] Table 2

[0082]

[0083]

[0084] Table 2 shows the results of theoretical tests on the proportion of light that can be effectively utilized at different angles, specifically the first angle θ1 and the second angle θ2. Table 2 illustrates the relationship between the reflection angle θ, the first angle θ1, and the second angle θ2 at the inclined surface, as well as the proportion of light that can be effectively utilized at different angles, specifically the first angle θ1 and the second angle θ2. As shown in Table 2, the optimal light utilization rate is achieved when the incident angle of the light, i.e., the first angle θ1, is 10°. When the second angle θ2 = 50°, the reflection angle θ of the light on the inclined contact surface is 50°. When the incident angle of the light, i.e., the first angle θ1, is 40°, a light utilization rate of 90% is achieved. When the second angle θ2 = 50°, the reflection angle θ of the light on the inclined contact surface is 80°.

[0085] According to Table 2, when the angle range of the first included angle θ1 is 10° to 40° and the angle range of the second included angle θ2 is 50° to 90°, the light utilization effect is better, with a utilization rate of 90% or more.

[0086] For example, when the preset angle is 60°, the preset light ratio can be the light ratio corresponding to the first included angle θ1 being 60° in Table 1, which is 74%.

[0087] Depend on Figure 1a According to the geometric relationships, the height (thickness) of the first dielectric structure 121 and the second dielectric structure 122 is... In practical applications, the width of the first cross-section of the first dielectric structure 121 in the sub-pixel unit is equal to the pixel width corresponding to the pixel resolution of the display substrate. When the pixel resolution is 600 PPI, the pixel width should be 42 μm. When the first included angle θ1 = 40° and the second included angle θ2 = 70°, according to the above formula... Where L is the pixel width, i.e., the width of the first cross-section, then the height (thickness) of the first dielectric structure 121 and the second dielectric structure 122 should be a = 27 μm; when the pixel resolution is 300 PPI, the pixel width should be 84 μm; when the first included angle θ1 = 40° and the second included angle θ2 = 70°, according to the above formula... Where L is the pixel width, i.e., the width of the first cross-section, then the height (thickness) of the first dielectric structure 121 and the second dielectric structure 122 should be a = 54um; when the pixel resolution is 160PPI, the pixel width should be 159um; when the first included angle θ1 = 40° and the second included angle θ2 = 70°, according to the above formula... Where L is the pixel width, i.e. the width of the first cross section, the height (thickness) of the first medium structure 121 and the second medium structure 122 should be a = 102um.

[0088] In this embodiment of the disclosure, quantifiable data on achieving total internal reflection under boundary conditions (incidence along the diagonal of the first cross section) can be obtained based on the relationship between the refractive index of the first dielectric structure 121 and the refractive index of the second dielectric structure 122. For example, the required height (thickness) of the first dielectric structure 121 and the second dielectric structure 122 at different pixel resolutions.

[0089] In some embodiments, the material of the first dielectric structure 121 is a siloxane material. In some embodiments, to improve the refractive index of the first dielectric structure 121, the material of the first dielectric structure 121 is a siloxane material doped with filler, the doping ratio of the filler is 50%, and the filler material includes titanium dioxide (TiO2) and / or zirconium dioxide (ZrO2). Doping with titanium dioxide (TiO2) filler can increase the refractive index of the first dielectric structure 121 by 0.3 to 0.4, and doping with zirconium dioxide (ZrO2) filler can increase the refractive index of the first dielectric structure 121 by 0.2 to 0.8.

[0090] In some embodiments, the first refractive index n1 ranges from 1.6 to 2.1.

[0091] In some embodiments, the main component of the material of the second dielectric structure 122 is a siloxane material. In order to reduce the refractive index of the second dielectric structure 122, the material of the second dielectric structure 122 is a siloxane material doped with hollow particles. The hollow particles are generally silicon dioxide (SiO2) spheres filled with gases such as air and nitrogen, and their particle size is between 10 nanometers and 100 nanometers.

[0092] In some embodiments, the second refractive index n2 ranges from 1.3 to 1.4.

[0093] Figure 6 This is a schematic diagram of the structure of another sub-pixel unit provided in an embodiment of the present disclosure, such as... Figure 6 As shown, in some embodiments, the sub-pixel unit further includes a light conversion unit 13, which is located on the side of the first medium structure 121 away from the light-emitting unit 11, and the light conversion unit 13 is correspondingly arranged with the first medium structure 121.

[0094] like Figure 6 As shown, the orthographic projection of the light conversion unit 13 on the substrate 21 at least partially overlaps with the orthographic projection of the corresponding light-emitting unit 11 on the substrate 21, and the orthographic projection of the light conversion unit 13 on the substrate 21 at least partially overlaps with the orthographic projection of the corresponding first dielectric structure 121 on the substrate 21.

[0095] Preferably, the orthographic projection of the light conversion unit 13 on the substrate 21 covers the orthographic projection of its corresponding light-emitting unit 11 on the substrate 21, and the orthographic projection of the light conversion unit 13 on the substrate 21 covers the orthographic projection of its corresponding first dielectric structure 121 on the substrate 21. This increases the area of ​​the light conversion unit 13 that receives light from the corresponding light-emitting unit 11, thereby improving the light extraction efficiency of the display substrate.

[0096] The light conversion unit 13 is used to convert the emitted color of the light-emitting unit 11 into the target emitted color.

[0097] In some embodiments, the light conversion unit 13 includes a quantum dot structure, which includes quantum dot (QD) particles.

[0098] In some embodiments, the light-emitting unit 11 is a blue OLED device, and the light-emitting unit 11 uses blue fluorescent material or phosphorescent material as the light source material to excite QD particles.

[0099] In some embodiments, the light conversion unit 13 includes a red light conversion unit or a green light conversion unit. The red light conversion unit includes a red quantum dot structure, and the green light conversion unit includes a green quantum dot structure. The red quantum dot structure is used to convert the blue light emitted by the blue OLED device into red light, and the green quantum dot structure is used to convert the blue light emitted by the blue OLED device into green light.

[0100] The light conversion unit 13 is composed of QD nanoparticles and scattering particles of different sizes mixed in resin. The doping ratio of the scattering particles is ≤60%. Generally, the QD particle size of the red light conversion unit is between 3 nm and 7 nm, and the QD particle size of the green light conversion unit is between 4 nm and 6 nm. The material of the QD particles can be one or more of ZnCdSe2, CdSe, CdTe, InP, and InAs. The material of the QD particles is not limited to the above materials and can be selected from group II-VI compounds, group III-V compounds, group IV-VI compounds, group IV elements, group IV compounds, and / or combinations thereof.

[0101] In some embodiments, the orthographic projection of the first dielectric structure 121 onto the plane containing the light-emitting surface of the light-emitting unit 11 covers the orthographic projection of the light-emitting unit 11 onto the plane containing the light-emitting surface.

[0102] Figure 7 This is a schematic diagram of another sub-pixel unit provided in an embodiment of the present disclosure, as shown below. Figure 7 As shown, in some embodiments, the sub-pixel unit further includes a light-transmitting unit 14, which is located on the side of the first medium structure 121 away from the light-emitting unit 11, and the light-transmitting unit 14 is correspondingly disposed with the first medium structure 121.

[0103] like Figure 7 As shown, the orthographic projection of the light-transmitting unit 14 on the substrate 21 at least partially overlaps with the orthographic projection of the corresponding light-emitting unit 11 on the substrate 21, and the orthographic projection of the light-transmitting unit 14 on the substrate 21 at least partially overlaps with the orthographic projection of the corresponding first dielectric structure 121 on the substrate 21.

[0104] In some embodiments, the orthographic projection of the light-transmitting unit 14 on the substrate layer 21 covers the orthographic projection of its corresponding light-emitting unit 11 on the substrate layer 21, and the orthographic projection of the light-transmitting unit 14 on the substrate layer 21 covers the orthographic projection of its corresponding first dielectric structure 121 on the substrate layer 21.

[0105] The light-transmitting unit 14 is used to transmit light emitted by the light-emitting unit 11 without changing the color of the light emitted by the light-emitting unit 11. For example, if the light emitted by the light-emitting unit 11 is blue light, then the light transmitted through the light-transmitting unit 14 is blue light.

[0106] In some embodiments, the material of the light-transmitting unit 14 is a material with a high refractive index, and a large number of scattering particles (doping ratio ≤60%) are distributed in the light-transmitting unit 14, or some blue dye is uniformly dispersed in the light-transmitting unit 14.

[0107] In some embodiments, the cross-sectional shape of the light-emitting unit 11 parallel to the plane containing the light-emitting surface can be rectangular. In some embodiments, the cross-sectional shape of the first dielectric structure 121 parallel to the plane containing the light-emitting surface of the light-emitting unit 11 can be rectangular. In some embodiments, the cross-sectional shape of the light conversion unit 13 parallel to the plane containing the light-emitting surface of the light-emitting unit 11 can be rectangular. In some embodiments, the cross-sectional shape of the light-transmitting unit 14 parallel to the plane containing the light-emitting surface of the light-emitting unit 11 can be rectangular.

[0108] In some embodiments, the height (thickness) a of the first dielectric structure 121 is the same as the height (thickness) of the second dielectric structure 122, and the bottom surface of the first dielectric structure 121 facing the light-emitting unit 11 is flush with the bottom surface of the second dielectric structure 122 facing the light-emitting unit 11, and the top surface of the first dielectric structure 121 facing away from the light-emitting unit 11 is flush with the top surface of the second dielectric structure 122 facing away from the light-emitting unit 11.

[0109] Figure 8 This is a planar schematic diagram of a display substrate provided in an embodiment of the present disclosure, as shown below. Figure 8As shown, the display substrate has a display area AA and a non-display area NA located outside the display area AA. The display area AA is provided with multiple scan lines GL and multiple data lines DL; the multiple scan lines GL and multiple data lines DL are intersected to define multiple sub-pixel units. For example, every three adjacent sub-pixel units along the row direction form a pixel unit, and three adjacent sub-pixel units (e.g., red sub-pixel unit R, green sub-pixel unit G, and blue sub-pixel unit B) are used to display different colors. Sub-pixel units located in the same row are provided with a scan signal by the same scan line GL, and sub-pixel units located in the same column are provided with a data voltage signal by the same data line DL. The non-display area NA may be provided with a gate driving circuit and a driving chip (not shown in the figure), with the scan lines GL connected to the gate driving circuit and the data lines DL connected to the driving chip.

[0110] Each sub-pixel unit includes a light-emitting unit and a corresponding pixel circuit. The pixel circuit is connected to a scan line GL and a data line DL. The pixel circuit is configured to provide a driving signal to the light-emitting unit based on the electrical signals provided by the scan line GL and the data line DL, thereby driving the light-emitting unit to emit light. For example, the pixel circuit includes at least a write transistor and a drive transistor. The gate of the write transistor is connected to the scan line GL. The write transistor is configured to transmit a data voltage signal provided by the data line DL to the gate of the drive transistor in response to the control of the scan signal provided by the scan line GL. The drive transistor provides a driving current to the light-emitting unit based on the voltage difference between its gate and its first electrode, thereby enabling the light-emitting unit to display. It should be noted that both the write transistor and the drive transistor can be thin-film transistors (TFTs). A TFT includes a gate, a first electrode, and a second electrode, wherein one of the first electrode and the second electrode is the source and the other is the drain.

[0111] Figure 9 This is a schematic diagram of the structure of a display substrate provided in an embodiment of the present disclosure, such as... Figure 9 As shown, the display substrate includes a base layer 21 and a plurality of sub-pixel units arranged in an array on one side of the base layer 21. At least a portion of the plurality of sub-pixel units constitute a pixel unit P, and each pixel unit P includes a plurality of sub-pixel units L.

[0112] For example, each pixel unit P includes three sub-pixel units L, which include a first sub-pixel unit L(R), a second sub-pixel unit L(G), and a third sub-pixel unit L(B). For example, the first sub-pixel unit L(R) is a red sub-pixel unit, the second sub-pixel unit L(G) is a green sub-pixel unit, and the third sub-pixel unit L(B) is a blue sub-pixel unit.

[0113] In this embodiment of the disclosure, each sub-pixel unit adopts the sub-pixel unit provided in the above embodiments.

[0114] In pixel unit P, multiple sub-pixel units L emit different colors of light, and the light-emitting units 11 corresponding to the multiple sub-pixel units L all emit blue light. For example, in pixel unit P, the multiple sub-pixel units L include a first sub-pixel unit L(R), a second sub-pixel unit L(G), and a third sub-pixel unit L(B). The first sub-pixel unit L(R) emits red light, the second sub-pixel unit L(G) emits green light, and the third sub-pixel unit L(B) emits blue light.

[0115] In the display substrate, the light-emitting units 11 in each sub-pixel unit L emit the same light color, and the light-emitting units 11 in each sub-pixel unit L emit the first light color, which is, for example, blue.

[0116] like Figure 9 As shown, the first sub-pixel unit L(R) includes a first light conversion unit 13(R), the second sub-pixel unit L(G) includes a second light conversion unit 13(G), and the third sub-pixel unit L(B) includes a light transmission unit 14(B).

[0117] The first light conversion unit 13(R) is used to convert the first emission color of the corresponding light-emitting unit 11 into a second emission color, for example, the second emission color is red. The second light conversion unit 13(G) is used to convert the first emission color of the corresponding light-emitting unit 11 into a third emission color, for example, the third emission color is green. The light-transmitting unit 14(B) is used to transmit the light emitted by the corresponding light-emitting unit 11 without changing the first emission color.

[0118] In this embodiment of the disclosure, the pixel circuit of the sub-pixel unit can be disposed on the substrate layer 21, and the pixel circuit is used to drive the light-emitting unit of each sub-pixel unit L on the substrate layer 21 to emit light.

[0119] In this embodiment of the present disclosure, the light-emitting unit 11 of each sub-pixel unit L is disposed on the substrate layer 21. Figure 10 This is a schematic diagram of the structure of the light-emitting unit of the sub-pixel unit in an embodiment of this disclosure, as shown below. Figure 10As shown, in each sub-pixel unit L, the light-emitting unit 11 may include: a first electrode 111, a second electrode 112, and a light-emitting functional layer 113. The first electrode 111 and the second electrode 112 are disposed opposite to each other, and the light-emitting functional layer 113 is located between the second electrode 112 and the first electrode 111. The first electrode 111 can be the anode of the light-emitting unit 11, and the second electrode 112 can be the cathode of the light-emitting unit 11. When a current is generated between the first electrode 111 and the second electrode 112, the light-emitting functional layer 113 emits light. The light-emitting functional layer 113 may include, in sequence, a hole injection layer, a hole transport layer, an organic light-emitting layer, an electron transport layer, and an electron injection layer. In this embodiment, the light-emitting unit 11 may be an OLED (Organic Light-Emitting Diode) device. In this case, the organic light-emitting layer uses an organic light-emitting material; for example, the OLED is a blue OLED.

[0120] In the embodiments disclosed herein, such as Figure 9 As shown, the display substrate also includes a thin film encapsulation (TFE) layer 22. The thin film encapsulation (TFE) layer 22 is located on the side of each light-emitting unit 11 away from the substrate layer 21. The thin film encapsulation (TFE) layer 22 is used to protect the light-emitting unit 11 from water and oxygen. The thin film encapsulation (TFE) layer 22 is formed by sequentially stacking a first inorganic material layer, an organic material layer, and a second inorganic material layer. The material of the first inorganic material layer can be silicon oxide, the organic material layer can be formed by inkjet printing (IJP), and the material of the second inorganic material layer can be silicon nitride.

[0121] In the embodiments disclosed herein, such as Figure 9 As shown, the light propagation unit 12 of each sub-pixel unit L is disposed on the side of the thin-film encapsulation (TFE) layer 22 away from the substrate layer 21. The light propagation unit 12 includes a first dielectric structure 121 and a second dielectric structure 122. In this embodiment, the second dielectric structure 122 fills the space between the first dielectric structures 121 of two adjacent sub-pixel units L, and the emission colors of the sub-pixel units corresponding to the two adjacent first dielectric structures 121 are different. For a detailed description of the first dielectric structure 121 in the light propagation unit 12, please refer to the relevant description in the above embodiments of the sub-pixel units, which will not be repeated here.

[0122] In the embodiments disclosed herein, such as Figure 9 As shown, the display substrate also includes a planarization layer 23, which is disposed on the side of each light propagation unit 12 away from the substrate layer 21. The planarization layer 23 is provided to planarize the light propagation unit 12 and to better fabricate the light conversion unit 13 and the light transmission unit 14.

[0123] In the embodiments disclosed herein, such as Figure 9As shown, the light conversion unit 13 of each sub-pixel unit L is disposed on the side of the planarization layer 23 away from the substrate layer 21, and the light transmission unit 14 of each sub-pixel unit L is disposed on the side of the planarization layer 23 away from the substrate layer 21. For example, each pixel unit P includes a first sub-pixel unit L(R), a second sub-pixel unit L(G) and a third sub-pixel unit L(B). The light conversion unit 13 of each sub-pixel unit L includes a first light conversion unit 13(R) of the first sub-pixel unit L(R) and a second light conversion unit 13(G) of the second sub-pixel unit L(G). The light transmission unit 14 of each sub-pixel unit L includes a light transmission unit 14(B) of the third sub-pixel unit L(B).

[0124] For a detailed description of the light conversion unit 13 and the light transmission unit 14, please refer to the relevant description in the above embodiments of the sub-pixel unit, which will not be repeated here.

[0125] In the embodiments disclosed herein, such as Figure 9 As shown, an isolation structure 24 is also provided between two adjacent light conversion units 13, and an isolation structure 24 is also provided between adjacent light conversion units 13 and light transmission units 14. The isolation structure 24 is a black matrix (BM) and is made of silicon-based organic resin, which is doped with carbon black and other substances to avoid crosstalk between light of different colors emitted by two adjacent sub-pixel units L. At the same time, it serves to limit the position of two adjacent light conversion units 13 and adjacent light conversion units 13 and light transmission units 14.

[0126] In the embodiments disclosed herein, such as Figure 9 As shown, an encapsulation structure layer 25 is also provided on the side of each light conversion unit 13, light transmission unit 14 and isolation structure 24 away from the substrate layer 21. The encapsulation structure layer 25 is made of a mixture of organic encapsulation material and inorganic particle scattering material.

[0127] This disclosure also provides a display device, which includes the display substrate provided in the above embodiments.

[0128] The display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator.

[0129] This disclosure also provides a method for fabricating sub-pixel units. Figure 11 A flowchart illustrating a method for fabricating a sub-pixel unit according to an embodiment of this disclosure is shown below. Figure 1a , Figure 2 ,and Figure 11 As shown, the preparation method includes:

[0130] Step S31: Provide the base layer 21.

[0131] Step S32: Form a light-emitting unit 11 on one side of the substrate layer 21.

[0132] Step S33: A light propagation unit 12 is formed on the side of the light-emitting unit 11 away from the substrate layer 21.

[0133] The light propagation unit 12 includes a first dielectric structure 121 and a second dielectric structure 122. The orthographic projection of the first dielectric structure 121 onto the substrate 21 at least partially overlaps with the orthographic projection of the light-emitting unit 11 onto the substrate 21. The second dielectric structure 122 is in contact with the first dielectric structure 121 on at least one side in a direction parallel to the plane of the substrate 21. The first dielectric structure 121 has a first refractive index, and the second dielectric structure 122 has a second refractive index, wherein the first refractive index is greater than the second refractive index. The first cross-section of the first dielectric structure 121 is located between the diagonal and the bottom edge. The first included angle is the total reflection angle of the contact surface between the first dielectric structure 121 and the second dielectric structure 122. The first cross section is the longitudinal cross section of the first dielectric structure 121 along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface of the light-emitting unit 11 (i.e., the AA' direction or the BB' direction). The first included angle is less than or equal to a preset angle so that among the light rays incident from the first dielectric structure 121 toward the bottom surface of the light-emitting unit 11 at any angle, light rays greater than or equal to a preset light ray ratio are emitted from the first dielectric structure 121 toward the top surface of the light-emitting unit 11. The preset angle is 60°.

[0134] This disclosure also provides a method for fabricating a display substrate, the method comprising: providing a substrate layer; forming a plurality of light-emitting units arranged in an array on one side of the substrate layer, each light-emitting unit corresponding to a sub-pixel unit, at least a portion of the plurality of sub-pixel units constituting a pixel unit; and forming a light propagation unit on the side of each light-emitting unit away from the substrate layer.

[0135] The light propagation unit includes a first dielectric structure and a second dielectric structure. The orthographic projection of the first dielectric structure onto the substrate layer at least partially overlaps with the orthographic projection of a light-emitting unit onto the substrate layer. The second dielectric structure and the first dielectric structure are in contact on at least one side in a direction parallel to the plane of the substrate layer. The first dielectric structure has a first refractive index, and the second dielectric structure has a second refractive index, wherein the first refractive index is greater than the second refractive index. The first angle between the diagonal of the first cross-section of the first dielectric structure and its bottom edge is equal to the total internal reflection angle of the contact surface between the first dielectric structure and the second dielectric structure. The first cross-section is a cross-section of the first dielectric structure along a direction perpendicular to the contact surface and perpendicular to the light-emitting surface. The first angle is less than or equal to a preset angle, such that among the light rays incident from the first dielectric structure toward the bottom surface of the light-emitting unit at any angle, a proportion of light rays greater than or equal to a preset proportion of light rays exit from the first dielectric structure toward the top surface of the light-emitting unit. The preset angle is 60°.

[0136] This disclosure also provides another method for preparing a display substrate. Figure 12 A flowchart illustrating a method for fabricating a display substrate according to an embodiment of this disclosure is shown below. Figure 9 and Figure 12 As shown, the preparation method includes:

[0137] Step S41: Provide the base layer 21.

[0138] Step S42: A plurality of sub-pixel units L are arranged in an array on one side of the substrate layer 21 to form a light-emitting unit 11.

[0139] Each light-emitting unit corresponds one-to-one with a sub-pixel unit, and at least some of the multiple sub-pixel units constitute a pixel unit.

[0140] Step S43: Perform a thin film encapsulation (TFE) process to form a thin film encapsulation layer 22 on the side of each light-emitting unit 11 away from the substrate layer 21.

[0141] Step S44: Form light propagation units 12 of each sub-pixel unit L on the side of the thin film encapsulation layer 22 away from the substrate layer 21.

[0142] Specifically, a second dielectric structure material layer is formed on the side of the thin film encapsulation layer 22 away from the substrate layer 21. The second dielectric structure material layer is patterned using photolithography to form a second dielectric structure 122 and a first dielectric structure region between the second dielectric structures 122 corresponding to the region corresponding to the light-emitting unit 11. A first dielectric structure material is formed in the first dielectric structure region and cured using ultraviolet (UV) exposure or thermal curing to form the first dielectric structure 121.

[0143] Step S45: A planarization layer 23 is formed on the side of the light propagation unit 12 of each sub-pixel unit L that is away from the base layer 21.

[0144] Step S46: An isolation structure 24 is formed on the side of the planarization layer 23 away from the substrate layer 21, and the light conversion unit region and the light transmission unit region are defined between the isolation structures 24.

[0145] Specifically, an isolation structure material layer is formed on the side of the planarization layer 23 away from the substrate layer 21. The isolation structure material layer is patterned using photolithography to form an isolation structure 24, as well as a light conversion unit region and a light transmission unit region corresponding to each light propagation unit 12.

[0146] Step S47: Form a corresponding light conversion unit 13 in the light conversion unit region and a light transmission unit 14 in the light transmission unit region.

[0147] Specifically, inkjet printing technology is used to fill the light conversion unit region with quantum dot structure material of corresponding color, such as quantum dot (QD) particle colloid, and solidify it to form light conversion unit 13 of each sub-pixel unit L, such as the first light conversion unit 13(R) of the first sub-pixel unit L(R) and the first light conversion unit 13(G) of the second sub-pixel unit L(G); light transmission unit material is filled in each light transmission unit region and solidified to form light transmission unit 14 of each sub-pixel unit L, such as the light transmission unit 14(B) of the third sub-pixel unit L(B).

[0148] Step S48: An encapsulation structure layer 25 is formed on the side of the light conversion unit 13, light transmission unit 14 and isolation structure 24 of each sub-pixel unit L away from the substrate layer 21.

[0149] Specifically, a mixed solution of organic encapsulation material and inorganic particle scattering material is used for encapsulation to form an encapsulation structure layer 25.

[0150] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A display substrate, comprising a substrate layer and a plurality of sub-pixel units arranged in an array on one side of the substrate layer, each sub-pixel unit corresponding to a light-emitting unit, and at least a portion of the plurality of sub-pixel units constituting a pixel unit; characterized in that, The sub-pixel unit further includes a light propagation unit located on one side of the light-emitting surface of the light-emitting unit; the light propagation unit includes a first dielectric structure and a second dielectric structure, wherein the orthographic projection of the first dielectric structure on the substrate layer at least partially overlaps with the orthographic projection of a light-emitting unit on the substrate layer, and the second dielectric structure is in contact with the first dielectric structure on at least one side in a direction parallel to the plane of the substrate layer. The first medium structure has a first refractive index, the second medium structure has a second refractive index, and the first refractive index is greater than the second refractive index; The first angle between the diagonal of the first cross section of the first dielectric structure and the bottom edge is equal to the total reflection angle of the contact surface between the first dielectric structure and the second dielectric structure. The first cross section is the cross section of the first dielectric structure along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface. The first included angle is less than or equal to a preset angle, so that among the light rays incident from the first medium structure toward the bottom surface of the light-emitting unit at any angle, light rays greater than or equal to a preset light ratio can all be emitted from the first medium structure toward the top surface of the light-emitting unit. The preset angle is 60°.

2. The display substrate according to claim 1, characterized in that, The angle of the first included angle ranges from 10° to 40°.

3. The display substrate according to claim 1, characterized in that, The height and width of the first cross-section of the first medium structure satisfy the following relationship: Where a is the height of the first cross section of the first dielectric structure, L is the width of the first cross section of the first dielectric structure, θ1 is the first included angle, and θ2 is the second included angle between the contact surface of the second dielectric structure with the first dielectric structure and the bottom surface facing the light-emitting unit.

4. The display substrate according to claim 3, characterized in that, The second included angle ranges from 10° to 90°.

5. The display substrate according to claim 4, characterized in that, The second included angle ranges from 50° to 90°.

6. The display substrate according to claim 3, characterized in that, The height of the first cross section ranges from 2 micrometers to 20 micrometers.

7. The display substrate according to claim 1, characterized in that, The sub-pixel unit further includes a light conversion unit, which is located on the side of the first medium structure away from the light-emitting unit; The orthographic projection of the light conversion unit on the substrate layer and the orthographic projection of the light emission unit on the substrate layer at least partially overlap; Furthermore, the orthographic projection of the light conversion unit on the substrate layer at least partially overlaps with the orthographic projection of the first dielectric structure on the substrate layer; The light conversion unit is used to convert the emitted color of the light-emitting unit into the target emitted color.

8. The display substrate according to claim 7, characterized in that, The light conversion unit includes a quantum dot structure.

9. The display substrate according to claim 1, characterized in that, The ratio of the second refractive index to the first refractive index ranges from 0.5 to 0.

9.

10. The display substrate according to claim 1, characterized in that, The orthographic projection of the first dielectric structure onto the plane where the light-emitting surface is located overlaps the orthographic projection of the light-emitting unit onto the plane where the light-emitting surface is located.

11. The display substrate according to claim 1, characterized in that, The first cross-section of the first dielectric structure is rectangular, and the cross-section of the second dielectric structure along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface is rectangular; or, the first cross-section of the first dielectric structure is inverted trapezoidal, and the cross-section of the second dielectric structure along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface is trapezoidal.

12. The display substrate according to claim 1, characterized in that, The second medium structure is disposed between two adjacent first medium structures, and the light emission colors of the sub-pixel units corresponding to the two adjacent first medium structures are different.

13. The display substrate according to claim 7, characterized in that, The orthographic projection of the light conversion unit on the substrate layer overlaps the orthographic projection of its corresponding light-emitting unit on the substrate layer.

14. The display substrate according to claim 1, characterized in that, The material of the second medium structure is a siloxane material doped with hollow particles.

15. The display substrate according to claim 1, characterized in that, The plurality of sub-pixel units include red sub-pixel units, green sub-pixel units and blue sub-pixel units, and the light-emitting units corresponding to the plurality of sub-pixel units emit light in blue.

16. The display substrate according to claim 1, characterized in that, Each pixel unit includes three sub-pixel units, which include a first sub-pixel unit, a second sub-pixel unit, and a third sub-pixel unit; The light emission color of the light emission unit corresponding to each of the multiple sub-pixel units is the first light emission color; The first sub-pixel unit includes a first light conversion unit, the second sub-pixel unit includes a second light conversion unit, and the third sub-pixel unit includes a light-transmitting unit; The first light conversion unit is used to convert the first emission color of the corresponding light-emitting unit into the second emission color; The second light conversion unit is used to convert the first emission color of the corresponding light-emitting unit into a third emission color; The light-transmitting unit is used to transmit light emitted by the corresponding light-emitting unit without changing the first light-emitting color.

17. The display substrate according to claim 16, characterized in that, The first emitting color is blue, the second emitting color is red, and the third emitting color is green.

18. A display device, characterized in that, Includes the display substrate as described in any one of claims 1-17.

19. A method for preparing a display substrate, characterized in that, include: Provide a base layer; Multiple light-emitting units are formed in an array on one side of the substrate layer, each light-emitting unit corresponds to a sub-pixel unit, and at least a portion of the multiple sub-pixel units constitute a pixel unit; A light propagation unit is formed on the side of each light-emitting unit away from the substrate layer. The light propagation unit includes a first dielectric structure and a second dielectric structure. The orthographic projection of the first dielectric structure on the substrate layer at least partially overlaps with the orthographic projection of one of the light-emitting units on the substrate layer. The second dielectric structure is in contact with the first dielectric structure on at least one side in a direction parallel to the plane of the substrate layer. The first medium structure has a first refractive index, the second medium structure has a second refractive index, and the first refractive index is greater than the second refractive index; Wherein, the first included angle between the diagonal of the first cross section of the first dielectric structure and the bottom edge is equal to the total reflection angle of the contact surface between the first dielectric structure and the second dielectric structure, and the first cross section is the cross section of the first dielectric structure along the direction perpendicular to the contact surface and perpendicular to the light-emitting surface; the first included angle is less than or equal to a preset angle, so that among the light rays incident from the first dielectric structure toward the bottom surface of the light-emitting unit at any angle, light rays greater than or equal to a preset light ray proportion are emitted from the first dielectric structure toward the top surface of the light-emitting unit, and the preset angle is 60°.

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