Display substrate, preparation method thereof and display device

Abstract

Provided is a display substrate, comprising: a back plate comprising a substrate and a driving circuit layer located on the substrate; the light-emitting device layer is located on the side, away from the substrate, of the driving circuit layer, the light-emitting device layer comprises a pixel defining layer and a light-emitting element, the pixel defining layer defines a pixel opening, and the light-emitting element is located at the pixel opening; the first packaging layer is positioned on one side, far away from the substrate, of the light-emitting device layer; the color film layer is located on the side, away from the substrate, of the first packaging layer, and the color film layer comprises a color filter unit and a black matrix; the display substrate further comprises a reflecting layer, the reflecting layer is located on at least part of the side wall of the black matrix, the orthographic projection of the reflecting layer on the substrate is annular, and the orthographic projection of the reflecting layer on the substrate surrounds the orthographic projection of the color filter unit on the substrate.

Description

Technical Field

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

[0002] Organic Light Emitting Diode (OLED) display panels have self-luminous properties, can achieve infinite contrast, present the purest black and richer color levels, and have ultra-thin design, excellent picture quality, fast response, energy saving and high efficiency, strong flexibility and good shock resistance. Traditional OLED display substrates use polarizers to reduce reflected glare and ensure normal use of the screen; but adding polarizers will lead to increased power consumption and a larger thickness. The color filter on encapsulation layer (COE) technology can be used to replace the polarizer, but due to the limitations of the exposure equipment, the alignment accuracy of the black matrix in the color filter layer prepared by COE is insufficient, and there are problems of offset and unevenness, resulting in poor brightness uniformity of the display substrate. Targeted improvement of these poor display problems is a topic that R&D personnel continue to pay attention to.

[0003] The above information disclosed in this section is only for understanding the background of the inventive concept of the present disclosure and therefore the above information may contain information that does not constitute the prior art. Summary of the invention

[0004] In order to solve at least one aspect of the above problems, embodiments of the present disclosure provide a display substrate and a method for manufacturing the same, and a display device.

[0005] According to one aspect of an embodiment of the present disclosure, a display substrate is provided, comprising:

[0006] A backplane, comprising a base substrate and a driving circuit layer located on the base substrate;

[0007] A light emitting device layer, located on a side of the driving circuit layer away from the base substrate, the light emitting device layer comprising a pixel defining layer and a light emitting element, the pixel defining layer defines a pixel opening, and at least a portion of the light emitting element is located at the pixel opening;

[0008] A first encapsulation layer is located on a side of the light-emitting device layer away from the substrate; and

[0009] a color filter layer, located on a side of the first encapsulation layer away from the base substrate, the color filter layer comprising a color filter unit and a black matrix,

[0010] Wherein, the display substrate further comprises:

[0011] A reflective layer, the reflective layer is located on at least a portion of the side wall of the black matrix, the orthographic projection of the reflective layer on the base substrate is annular, and the orthographic projection of the reflective layer on the base substrate surrounds the orthographic projection of the color filter unit on the base substrate.

[0012] In some embodiments, the orthographic projection of the light emitting element on the base substrate at least partially overlaps with the orthographic projection of the color filter unit on the base substrate; a plurality of the color filter units are arranged in an array, the black matrix separates the plurality of the color filter units, and the reflective layer is arranged in an array; and

[0013] The reflective layer is configured to reflect at least a portion of the light emitted by the light emitting element and emit the light after passing through the color filter unit.

[0014] In some embodiments, the material of the reflective layer includes metal or metal alloy; or the reflective layer includes an anti-reflective film; and / or,

[0015] The thickness of the reflective layer is less than or equal to 1 μm.

[0016] In some embodiments, a cross section of the black matrix parallel to the third direction is an inverted trapezoid; or

[0017] The cross section of the black matrix parallel to the third direction is in a convex shape, and the protruding portion of the convex shape is at least partially higher than the height of the cross section of the color filter unit parallel to the third direction;

[0018] The third direction is parallel to the light emitting direction of the base substrate.

[0019] In some embodiments, the display substrate further comprises:

[0020] a first refractive index region, the first refractive index region being located at a side of the color filter layer away from the base substrate, and an orthographic projection of the first refractive index region on the base substrate covering an orthographic projection of the reflective layer on the base substrate; and

[0021] The refractive index of the first refractive index region is greater than the refractive index of the color filter unit, and the first refractive index region is configured to converge light.

[0022] In some embodiments, the orthographic projection of the first refractive index region on the substrate is a ring structure, and the first refractive index regions are arranged in an array; and

[0023] The orthographic projection of the first refractive index region on the base substrate partially overlaps with the orthographic projection of the color filter unit on the base substrate.

[0024] In some embodiments, the display substrate further comprises:

[0025] a second refractive index region, the second refractive index region being located at a side of the color filter layer away from the base substrate, and an orthographic projection of the second refractive index region on the base substrate being located within an orthographic projection of the color filter unit on the base substrate; and

[0026] The refractive index of the second refractive index region is smaller than the refractive index of the color filter unit, and the second refractive index region is configured to diverge light.

[0027] In some embodiments, the second refractive index regions are arranged in an array, and the orthographic projection of the first refractive index region on the base substrate surrounds the orthographic projection of the second refractive index region on the base substrate.

[0028] In some embodiments, the display substrate further comprises:

[0029] a microlens structure layer, the microlens structure layer being located on a side of the color filter layer away from the base substrate, the microlens structure layer comprising a plurality of microlenses and a filling layer covering the microlenses, the plurality of microlenses being arranged in a matrix, and the microlenses being configured to diverge light; and

[0030] The orthographic projection of the microlens structure layer on the base substrate is located within the orthographic projection of the color filter unit on the base substrate.

[0031] In some embodiments, the refractive index of the microlens is greater than the refractive index of the filling layer, and the microlens is a concave lens; and / or,

[0032] The material of the microlens is selected from polyimide and photosensitive resin.

[0033] Another aspect of the embodiments of the present disclosure provides a display device, comprising a display substrate as described in any one of the above items.

[0034] Another aspect of the embodiments of the present disclosure provides a method for preparing a display substrate, the method comprising the following steps:

[0035] forming a driving circuit layer on the base substrate;

[0036] A light emitting device layer is formed on a side of the driving circuit layer away from the base substrate, wherein the light emitting device layer includes a pixel defining layer and a light emitting element, the pixel defining layer defines a pixel opening, and at least a portion of the light emitting element is located at the pixel opening;

[0037] forming a first encapsulation layer on a side of the light emitting device layer away from the substrate;

[0038] forming a black matrix on a side of the first encapsulation layer away from the base substrate;

[0039] forming a reflective layer on at least a portion of the sidewalls of the black matrix, wherein the orthographic projection of the reflective layer on the base substrate is a ring; and

[0040] A color filter unit is formed on a side of the first encapsulation layer away from the base substrate, wherein the orthographic projection of the reflective layer on the base substrate surrounds the orthographic projection of the color filter unit on the base substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other objects and advantages of the present disclosure will be apparent from the following description of the present disclosure with reference to the accompanying drawings and will help to have a comprehensive understanding of the present disclosure.

[0042] Figure 1 A schematic diagram of a light path of a display substrate of a related art in a cross section parallel to a light emitting direction is schematically shown;

[0043] Figure 2A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some exemplary embodiments of the present disclosure;

[0044] Figure 2B is a schematic diagram of a light path of a display substrate in a cross section parallel to a light emitting direction according to some exemplary embodiments of the present disclosure;

[0045] Figure 2C is a plan view of a display substrate according to some exemplary embodiments of the present disclosure;

[0046] Figure 2D is a cross-sectional view showing a light-emitting layer in a substrate according to some exemplary embodiments of the present disclosure;

[0047] Figure 3A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0048] Figure 3B is a schematic diagram of a light path of a display substrate in a cross section parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0049] Figure 4A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0050] Figure 4B is a schematic diagram of a light path of a display substrate in a cross section parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0051] Figure 5A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0052] Figure 5B is a schematic diagram of a light path of a display substrate in a cross section parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0053] Figure 5C is a plan view of a display substrate according to some other exemplary embodiments of the present disclosure;

[0054] Fig. 6A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0055] Figure 6B is a schematic diagram of a light path of a display substrate in a cross section parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0056] Figure 6C is a plan view of a display substrate according to some other exemplary embodiments of the present disclosure;

[0057] Fig.6D is a cross-sectional view of a microlens structure layer in a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure;

[0058] Figure 7 is a schematic structural diagram of a display device provided by an embodiment of the present disclosure;

[0059] Figure 8 is a flow chart of a method for preparing a display substrate according to an exemplary embodiment of the present disclosure.

[0060] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the sizes of layers, structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0061] The technical solution of the present disclosure is further specifically described below through examples and in conjunction with the accompanying drawings. In the specification, the same or similar figure numbers indicate the same or similar parts. The following description of the embodiments of the present disclosure with reference to the accompanying drawings is intended to explain the overall inventive concept of the present disclosure and should not be construed as a limitation of the present disclosure.

[0062] In addition, in the following detailed description, for the purpose of explanation, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details.

[0063] It should be understood that, although the terms first, second, etc. can be used here to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the exemplary embodiment, the first element can be named as the second element, and similarly, the second element can be named as the first element. The term "and / or" as used herein includes any combination and all combinations of one or more related listed items.

[0064] It should be understood that when an element or layer is referred to as being "formed on" another element or layer, the element or layer may be formed directly or indirectly on another element or layer. That is, for example, there may be an intermediate element or intermediate layer. On the contrary, when an element or layer is referred to as being "formed directly on" another element or layer, there is no intermediate element or intermediate layer. Other words used to describe the relationship between elements or layers (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.) should be interpreted in a similar manner. In addition, the X-axis, Y-axis and Z-axis are not limited to the three axes of the rectangular coordinate system, and can be interpreted in a broader sense. For example, the X-axis, Y-axis and Z-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of X, Y and Z" and "at least one selected from the group consisting of X, Y and Z" may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y and Z such as XYZ, XY, YZ and XZ.

[0065] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. It will also be understood that when the terms "comprise" and / or "include" are used herein, the description indicates the presence of the features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0066] Figure 1 The light path diagram of a display substrate of the related art along a cross section parallel to the light emitting direction is schematically shown. Figure 2A is a cross-sectional view of a display substrate according to some exemplary embodiments of the present disclosure in a direction parallel to a light emitting direction, Figure 2B is a schematic diagram of a light path of a display substrate along a cross section parallel to a light emitting direction according to some exemplary embodiments of the present disclosure, Figure 2C is a plan view of a display substrate according to some exemplary embodiments of the present disclosure, for example, Figure 2A It can be a display substrate along Figure 2CA cross-sectional view taken along line AA'.

[0067] Reference Figure 1 The display substrate 10 includes a backplane 1, a light-emitting device layer 2, a first encapsulation layer 3 and a color filter layer 4, and the color filter layer 4 includes a color filter unit 41 and a black matrix 42. The light emitted by the light-emitting device layer 2 passes through the first encapsulation layer 3 and the color filter layer 4 in sequence and then is emitted. Most of the light is emitted along the optical path a, and a part of the light passes through the side wall of the color filter layer 4 along the optical path b and is incident on the black matrix 42 and absorbed, resulting in a large difference in brightness between the center and the surroundings of the color filter unit 41, and uneven display brightness.

[0068] In order to solve this problem, the display substrate 20 of the embodiment of the present disclosure is further provided with a reflective layer 43 .

[0069] In the exemplary embodiment of the present disclosure, referring to Figure 2A-2B The display substrate 20 includes: a backplane 1, including a base substrate 11 and a driving circuit layer 12 located on the base substrate 11; a light-emitting device layer 2, located on the side of the driving circuit layer 12 away from the base substrate 11, the light-emitting device layer 2 includes a pixel defining layer 22 and a light-emitting element 21, the pixel defining layer 22 defines a pixel opening 214, and at least a portion of the light-emitting element 21 is located at the pixel opening 214; a first encapsulation layer 3, located on the side of the light-emitting device layer 2 away from the base substrate 11; and a color filter layer 4, located on the side of the first encapsulation layer 3 away from the base substrate 11, the color filter layer 4 includes a color filter unit 41 and a black matrix 42. The display substrate 20 also includes: a reflective layer 43, the reflective layer 43 is located on at least a portion of the sidewall of the black matrix 42, such as Figure 2C As shown, the orthographic projection of the reflective layer 43 on the base substrate 11 is ring-shaped, and the orthographic projection of the reflective layer 43 on the base substrate 11 surrounds the orthographic projection of the color filter unit 41 on the base substrate 11 .

[0070] According to some exemplary embodiments, the base substrate 11 can be a rigid substrate, such as a glass substrate, a silicon substrate, etc., or can be formed of a flexible material with excellent heat resistance and durability, such as polyimide (PI), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene, polyacrylate, polyarylate, polyetherimide, polyethersulfone, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polysulfone (PSF), polymethyl methacrylate (PMMA), triacetyl cellulose (TAC), cycloolefin polymer (COP) and cycloolefin copolymer (COC), etc.

[0071] In an exemplary embodiment of the present disclosure, the driving circuit layer 12 may include a plurality of thin film transistors and storage capacitors forming a pixel driving circuit. In an exemplary embodiment, the driving circuit layer 12 may include, for example, a first insulating layer, a semiconductor layer, a second insulating layer, a first gate metal layer, a third insulating layer, a second gate metal layer, a fourth insulating layer, a source-drain metal layer, and a planar layer sequentially disposed on the base substrate 11.

[0072] Figure 2D is a cross-sectional view of a light emitting layer in a display substrate according to some exemplary embodiments of the present disclosure.

[0073] Exemplarily, the light-emitting element 21 includes a first electrode 211, a light-emitting layer 212, and a second electrode 213 that are stacked. It should be noted that the "light-emitting layer" here is an overview of the various functional layers of the OLED display light-emitting element, for example, it may include various functional layers such as a hole injection layer 2121, a hole transport layer 2122, an electron transport layer 2124, an electron injection layer 2125, and an organic light-emitting layer 2123. Optionally, the organic light-emitting layer 2123 is one of a blue light-emitting layer, a red light-emitting layer, a green light-emitting layer, or a white light-emitting layer to form a red sub-pixel R, a green sub-pixel G, a blue sub-pixel B, and a white sub-pixel.

[0074] For example, the first electrode 211 is an anode, and the second electrode 213 is a cathode. The materials of the first electrode 211 and the second electrode 213 may be, for example, at least one of metal and ITO. For example, the second electrode 213 may be an ITO layer of a display substrate. When the ITO layer is used as an electrode layer of a display substrate, it has good electrical conductivity and high transmittance to visible light, and can conduct current without blocking the light emitted by the light-emitting layer 212.

[0075] The pixel defining layer 22 is disposed on the side of the driving circuit layer 12 away from the base substrate. The pixel defining layer 22 has a plurality of pixel openings 214 spaced apart from each other. The pixel openings 214 are used to form corresponding sub-pixel regions such as red sub-pixels R, green sub-pixels G, and blue sub-pixels B. The first electrode 211 is disposed at the bottom of the pixel opening 214. The light-emitting layer 212 is disposed on the first electrode 211 in the pixel opening 214. The second electrode 213 is disposed on the pixel defining layer 22. The coverage area of ​​the second electrode 213 includes the pixel opening 214 and the non-pixel opening area. In this way, the first electrode 211 and the second electrode 213 can drive the light-emitting layer 212 to emit light when a voltage is connected.

[0076] For example, the pixel defining layer 22 is located on the side of the flat layer away from the base substrate 11, and the first electrode 211 can contact the circuits or conductive traces inside the driving circuit layer 12 through multiple vias arranged in the flat layer, so that the light-emitting elements 21 can be driven separately through the driving circuit layer 12 to achieve the display function.

[0077] A first encapsulation layer 3, such as a thin film encapsulation layer, is disposed on the second electrode 213 to prevent external water vapor and oxygen from entering the light-emitting device layer 2. For example, the first encapsulation layer 3 includes an inorganic material, and the preparation method is related to the material selection, such as using a chemical vapor deposition process to deposit SiN x , SiON materials, or Al2O3 materials deposited using atomic layer deposition process.

[0078] In the COE technology, the display substrate 20 uses a color filter layer 4 to replace the polarizer. The orthographic projection of the light-emitting element 21 on the base substrate 11 overlaps at least partially with the orthographic projection of the color filter unit 41 on the base substrate 11. The color filter unit 41 is used to filter the light of different colors emitted by the light-emitting element 21. The color filter layer 4 includes a color filter unit 41 and a black matrix 42. The color filter unit 41 includes a red color filter (Red), a green color filter (Green) and a blue color filter (Blue). The red color filter, the green color filter and the blue color filter correspond to the outgoing light of the red sub-pixel R, the green sub-pixel G and the blue sub-pixel B respectively. The black matrix 42 is used to prevent the display substrate 20 from leaking light and avoid reducing the reflectivity of the display substrate 20. The COE structure can effectively improve the transmittance of the display substrate 20 and reduce the power consumption of the light-emitting device layer 2. At the same time, the thickness of the display substrate 20 will be thinner, reducing the difficulty of laminating the display substrate 20.

[0079] like Figure 2B As shown, the reflective layer 43 is located on at least part of the side wall of the black matrix 42. The reflective layer 43 reflects the light passing through the side wall of the color filter unit 41, and emits it through the light emitting surface of the color filter unit 41, that is, emits it along the optical path d, thereby preventing the light from being absorbed by the black matrix 42 and enhancing the light emission intensity of the display substrate 20. By designing the thickness, refractive index, etc. of the first encapsulation layer 3 and the color filter unit 41, most of the light reflected along the reflective layer 43 is emitted along the four sides of the color filter unit 41, and most of the light is emitted along the optical path c. In the embodiment of the present disclosure, by enhancing the edge light emission intensity, the light intensity difference between the edge and the middle of the color filter unit 41 is reduced, and the brightness uniformity of the display substrate 20 is improved, thereby enhancing the visual experience of the user.

[0080] Exemplarily, a second encapsulation layer 5 is further provided on the color filter layer 4, and the second encapsulation layer 5 is used to isolate external water and oxygen and protect the internal structure of the display substrate 20. For example, the second encapsulation layer 5 may be a glass cover plate.

[0081] In some embodiments of the present disclosure, Figure 2C As shown, the orthographic projection of the reflective layer 43 on the base substrate 11 is ring-shaped, and the orthographic projection of the reflective layer 43 on the base substrate 11 surrounds the orthographic projection of the color filter unit 41 on the base substrate 11 .

[0082] In some embodiments of the present disclosure, a plurality of color filter units 41 are arranged in an array, a black matrix 42 separates the plurality of color filter units 41, and a reflective layer 43 is arranged in an array. The reflective layer 43 is configured to reflect at least part of the light emitted by the light emitting element 21 and emit it after passing through the color filter unit 41.

[0083] The display substrate 20 includes a plurality of color filter units 41, and the plurality of color filter units 41 are arranged in an array along a first direction and a second direction. Exemplarily, the first direction intersects with the second direction. For example, in the illustrated example, the first direction is the X direction, the second direction is the Y direction, and the first direction X and the second direction Y are perpendicular to each other. The reflective layer 43 is arranged around the side wall of the color filter unit 41, and the positive projection of the reflective layer 43 on the base substrate 11 is a plurality of annular structures arranged in an array, which improves the brightness uniformity of the entire display substrate 20.

[0084] In the embodiment of the present disclosure, there is no special limitation on the material for making the reflective layer 43, as long as the reflective performance of the reflective layer 43 can be guaranteed. In one embodiment, the reflective layer 43 is made of a metal material or a metal alloy. Exemplarily, one or more materials selected from metal aluminum and silver can be selected to make the reflective layer 43, or an anti-reflection film can be directly attached as the reflective layer 43. In the embodiment of the present disclosure, there is no special limitation on the thickness of the reflective layer 43, for example, the thickness of the reflective layer 43 is set to be less than or equal to 1 μm.

[0085] Figure 3A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure, Figure 3B Schematic diagram of the light path of a display substrate along a cross section parallel to the light emitting direction according to some other exemplary embodiments of the present disclosure. Figure 3A-3B Some structures of the display substrate shown can refer to the above Figure 2A-2B Moreover, the same or similar components or structures are represented by the same reference numerals.

[0086] In an embodiment of the present disclosure, the cross section of the black matrix 42 along the third direction parallel to the light emitting direction of the base substrate is an inverted trapezoid, and the third direction is parallel to the light emitting direction of the base substrate. Wherein, the third direction is parallel to the light emitting direction of the display substrate. Exemplarily, the third direction intersects with the first direction, for example, in the illustrated example, the first direction is the X direction, the third direction is the Z direction, and the first direction X and the third direction Z are perpendicular to each other.

[0087] Reference Figure 3A The cross section of the black matrix 42 is an inverted trapezoid, and the angle α between the reflective layer 43 formed on the side wall of the black matrix 42 and the third direction Z is an acute angle. Figure 3B Most of the light is emitted along the light path e, and part of the light is emitted along the light path f. Through the reflection of the reflective layer 43, the edge light intensity is enhanced, and the light intensity difference between the edge and the middle of the color filter unit 41 is reduced. At the same time, the reflected light is emitted obliquely along the light emitting surface of the color filter unit 41, thereby improving the brightness of the side viewing angle, which can improve the problem of dim side viewing angle of the product and improve the picture quality.

[0088] Figure 4A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure, Figure 4B Schematic diagram of the light path of a display substrate along a cross section parallel to the light emitting direction according to some other exemplary embodiments of the present disclosure. Figure 4A-4B Some structures of the display substrate shown can refer to the above Figure 2A-2B Moreover, the same or similar components or structures are represented by the same reference numerals.

[0089] For example, refer to Figure 2A and Figure 2B The cross section of the black matrix 42 parallel to the third direction is convex, and the protruding portion of the convex is at least partially higher than the height of the cross section of the color filter unit 41 parallel to the third direction.

[0090] Reference Figure 2B The cross section of the black matrix 42 is a convex shape, and part of the light will be emitted along the optical path g. Since the height h2 of the black matrix 42 is higher than the height h1 of the color filter unit 41, the convex part of the convex shape can absorb this part of the light, thereby preventing the color filter units 41 of different colors from mixing colors. It should be noted that the height is the length of the cross section along the third direction Z.

[0091] In some embodiments of the present disclosure, referring to Figure 4A and Figure 4B The display substrate 20 further includes: a first refractive index region 44, the first refractive index region 44 is located on the side of the color filter layer 4 away from the base substrate 11, and the orthographic projection of the first refractive index region 44 on the base substrate 11 covers the orthographic projection of the reflective layer 43 on the base substrate 11. The refractive index of the first refractive index region 44 is greater than the refractive index of the color filter unit 41, and the first refractive index region 44 is configured to converge light.

[0092] Reference Figure 4AThe first refractive index region 44 is located at the edge portion above the color filter unit 41 and does not completely cover the color filter unit 41. Its function is to converge the light emitted from the edge portion of the color filter unit 41. Figure 4B Most of the light is emitted along the optical path h, and part of the light is emitted along the optical path i. After being reflected by the reflective layer 43, this part of the light passes through the color filter unit 41 and is incident on the first refractive index area 44. Since the refractive index of the first refractive index area 44 is greater than the refractive index of the color filter unit 41, the first refractive index area 44 converges this part of the light, thereby enhancing the light intensity there, and further converges the light emitted from the edge of the color filter unit 41, thereby preventing the light of different colors of the color filter unit 41 from mixing.

[0093] Figure 5A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure, Figure 5B Schematic diagram of the light path of a display substrate along a cross section parallel to the light emitting direction according to some other exemplary embodiments of the present disclosure. Figure 5A-Figure 5B Some structures of the display substrate shown can refer to the above Figure 2A-2B Moreover, the same or similar components or structures are represented by the same reference numerals.

[0094] In some embodiments of the present disclosure, referring to Figure 5A and Figure 5B The display substrate 20 further includes: a second refractive index region 45, the second refractive index region 45 is located on the side of the color filter layer 4 away from the base substrate 11, and the orthographic projection of the second refractive index region 45 on the base substrate 11 is located within the orthographic projection of the color filter unit 41 on the base substrate 11. The refractive index of the second refractive index region 45 is less than the refractive index of the color filter unit 41, and the second refractive index region 45 is configured to diverge the light.

[0095] Reference Figure 5A The second refractive index region 45 is located in the middle part above the color filter unit 41, and does not completely cover the color filter unit 41. Its function is to diverge the light emitted from the middle part of the color filter unit 41. Exemplarily, the second refractive index region 45 is close to the first refractive index region 44. Figure 5B Most of the light is emitted along the optical path j, and some of the light is emitted along the optical path k. The light emitted along the optical path j is emitted from the light exiting surface of the color filter unit 41 and enters the second refractive index area 45. Since the refractive index of the second refractive index area 45 is smaller than the refractive index of the color filter unit 41, the intensity of the emitted light in the middle of the color filter unit 41 is dispersed, which makes up for the intensity of the edge light and reduces the light intensity difference between the edge and the middle of the color filter unit 41, thereby enhancing the symmetry and uniformity of the emitted light of the display substrate.

[0096] Figure 5C is a plan view of a display substrate according to some other exemplary embodiments of the present disclosure. For example, Figure 5A The display substrate according to other exemplary embodiments of the present disclosure may be Figure 5C A cross-sectional view taken along line BB'.

[0097] In some embodiments of the present disclosure, the orthographic projection of the first refractive index region 44 on the substrate 11 is a ring structure, and the first refractive index region 44 is arranged in an array. The orthographic projection of the first refractive index region 44 on the substrate 11 partially overlaps with the orthographic projection of the color filter unit 41 on the substrate 11. The second refractive index region 45 is arranged in an array. The orthographic projection of the first refractive index region 44 on the substrate 11 surrounds the orthographic projection of the second refractive index region 45 on the substrate 11.

[0098] The orthographic projections of the first refractive index region 44 and the second refractive index region 45 on the base substrate 11 are arranged in an array along the first direction and the second direction. The orthographic projections of the first refractive index region 44 and the second refractive index region 45 on the base substrate 11 cover the orthographic projections of the color filter unit 41 on the base substrate 11. The first refractive index region 44 and the second refractive index region 45 jointly regulate the light output uniformity of the color filter unit 41.

[0099] Fig. 6A is a cross-sectional view of a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure, Figure 6B is a schematic diagram of a light path of a display substrate along a cross section parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure, Figure 6C is a plan view of a display substrate according to some other exemplary embodiments of the present disclosure. For example, Fig. 6A The display substrate according to other exemplary embodiments of the present disclosure may be Figure 6B A cross-sectional view taken along line CC'. Fig.6D is a cross-sectional view of a microlens structure layer in a display substrate along a direction parallel to a light emitting direction according to some other exemplary embodiments of the present disclosure. Figure 6A-6D Some structures of the display substrate shown can refer to the above Figure 2A-2D Moreover, the same or similar components or structures are represented by the same reference numerals.

[0100] In some embodiments of the present disclosure, the display substrate 20 further includes: a microlens structure layer 46, the microlens structure layer 46 is located on the side of the color filter layer 4 away from the base substrate 11, and the microlens structure layer 46 includes a plurality of microlenses 461 and a filling layer 462 covering the microlenses. The microlenses 461 are configured to diverge light. The orthographic projection of the microlens structure layer 46 on the base substrate 11 is located within the orthographic projection of the color filter unit 41 on the base substrate 11.

[0101] Reference Fig. 6A The microlens structure layer 46 is located in the middle part above the color filter unit 41, and does not completely cover the color filter unit 41. Its function is to diverge the light emitted from the middle part of the color filter unit 41. Exemplarily, the microlens structure layer 46 is close to the first refractive index area 44. Figure 6B Most of the light is emitted along the light path l, and part of the light is emitted along the light path m. The light emitted along the light path l is emitted from the light exiting surface of the color filter unit 41 and enters the microlens structure layer 46. Due to the divergent effect of the microlens 461, the intensity of the emitted light in the middle of the color filter unit 41 is dispersed, the intensity of the edge light is compensated, and the difference in light intensity between the edge and the middle of the color filter unit 41 is reduced, thereby enhancing the symmetry and uniformity of the emitted light of the display substrate.

[0102] Reference Figure 6C , a plurality of micro lenses 461 are arranged in a matrix in the micro lens structure layer 46, and are used to diverge the light in the middle of the color filter unit 41, further compensating for the light intensity difference between the edge and the middle of the color filter unit 41, and improving the light uniformity of the display substrate 20. Fig.6D The microlens 461 is a concave lens and can be prepared by etching process. The material of the microlens 461 is selected from one of polyimide and photosensitive resin. The refractive index of the microlens 461 is greater than the refractive index of the filling layer 462, and the material of the filling layer 462 can be photoresist.

[0103] In the display substrate provided by the embodiment of the present disclosure, by setting a reflective layer on the side wall of the black matrix, the angle of light emitted from the edge of the color filter unit can be adjusted, and by changing the angle of light emitted from the edge of the color filter unit, the light intensity at that location is enhanced, the intensity of the edge light is compensated, and the light intensity difference between the edge and the middle of the color filter unit is reduced, thereby enhancing the symmetry and uniformity of the light emitted from the display substrate and ensuring the user's visual experience. Further, by setting a first refractive index region, a second refractive index region and / or a microlens structure layer on the color filter layer, the light intensity emitted from the edge of the color filter unit and the light intensity emitted from the middle of the color filter unit are modulated, so that the luminous intensity distribution of the color filter unit is redefined, which can cope with the problem of different black matrix alignment accuracy caused by equipment limitations under COE technology, thereby enhancing the user's visual experience.

[0104] The embodiment of the present disclosure also provides a display device, such as Figure 7 As shown, Figure 7A structural schematic diagram of a display device 100 provided in an embodiment of the present disclosure, wherein the display device 100 includes a device body 30 and a display substrate 20 disposed on the device body 30, wherein the device body 30 includes a shell and components such as a processor, a power supply, and a camera disposed in the shell, and the display device 100 can adopt the display substrate 20 provided in the above embodiment.

[0105] The display device 100 may include any device or product having a display function. For example, the display device 100 may be a smart phone, a mobile phone, an e-book reader, a desktop computer (PC), a laptop PC, a netbook PC, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital audio player, a mobile medical device, a camera, a wearable device (such as a head-mounted device, an electronic clothing, an electronic bracelet, an electronic necklace, an electronic accessory, an electronic tattoo, or a smart watch), a television, etc.

[0106] It should be understood that the display device 100 according to some exemplary embodiments of the present disclosure has all the features and advantages of the above-mentioned display substrate 20 , and these features and advantages can be referred to the above description of the display substrate 20 , which will not be repeated here.

[0107] Figure 8 The flowchart of the method for preparing a display substrate according to an embodiment of the present disclosure is schematically shown.

[0108] According to some exemplary embodiments, referring to Figure 2A , the method for preparing the display substrate includes the following steps S810 to S860.

[0109] In step S810 , a driving circuit layer 12 is formed on the base substrate 11 .

[0110] In step S820 , a light-emitting device layer 2 is formed on the side of the driving circuit layer 12 away from the base substrate 11 ; the light-emitting device layer 2 includes a pixel defining layer 22 and a light-emitting element 21 , the pixel defining layer 22 defines a pixel opening 214 , and at least a portion of the light-emitting element 21 is located at the pixel opening 214 .

[0111] In step S830 , a first encapsulation layer 3 is formed on a side of the light emitting device layer 2 away from the base substrate 11 .

[0112] In step S840, a black matrix 42 is formed on a side of the first encapsulation layer 3 away from the base substrate 11;

[0113] In step S850 , a reflective layer 43 is formed on at least a portion of the sidewall of the black matrix 42 , and the orthographic projection of the reflective layer 43 on the base substrate 11 is a ring.

[0114] In step S860 , a color filter unit 41 is formed on a side of the first encapsulation layer 3 away from the base substrate 11 ; the orthographic projection of the reflective layer 43 on the base substrate 11 surrounds the orthographic projection of the color filter unit 41 on the base substrate 11 .

[0115] Exemplarily, a driving circuit layer 12 is disposed on the base substrate 11, and in the direction in which the driving circuit layer 12 is away from the base substrate 11, a pixel defining layer 22 is formed by coating and photo process, and a first electrode 211 is formed by etching process. Afterwards, an evaporation process is used to complete the light-emitting layer 212 and the second electrode 213 at one time in the direction in which the first electrode 211 is away from the base substrate 11, and then a first encapsulation layer 3 is disposed in the direction in which the second electrode 213 is away from the base substrate 11.

[0116] It should be noted that the substrate 11 may be a rigid substrate (substrate) or a flexible substrate (substrate), including but not limited to glass and polyimide.

[0117] The light-emitting layer 212 may be a single-layer structure, or may include other multi-layer structures such as an electron injection layer 2121 , an electron transport layer 2122 , a hole injection layer 2124 , a hole transport layer 2125 and an organic light-emitting layer 2123 .

[0118] The first packaging layer 3 can be a rigid packaging or a flexible packaging, which is selected according to the final use requirements of the display substrate 20 .

[0119] A color filter layer 4 is provided on the side of the first encapsulation layer 3 away from the base substrate 11. First, a black matrix 42 is formed on the side of the first encapsulation layer 3 away from the base substrate 11 by etching process. The black matrix 42 is a truncated cone-shaped matrix corresponding to a plurality of light-emitting elements 21. Preferably, the cross section of the black matrix 42 parallel to the light-emitting direction of the base substrate 11 can be set to be an inverted trapezoid, and the material can be black polyimide. Then, a reflective layer 43 is formed on the two side surfaces of the black matrix 42 parallel to the light-emitting direction of the base substrate 11 by metal sputtering or evaporation. The available materials include but are not limited to metals such as Al and Ag, or directly attaching an anti-reflection film. Finally, between each matrix of the black matrix 42, a red, green, and blue color filter unit 41 is formed by evaporation or deposition of a transparent color film technology.

[0120] In the display substrate 20, the light emitted by the light-emitting layer 212 of a certain color sub-pixel will be reflected by the reflective layer 43 within a specified angle. If the light exceeds the specified angle, it will be absorbed at the bottom of the black matrix 42. The specified angle is related to the thickness of the first encapsulation layer 3, the thickness of the color filter unit 41, and the size, thickness, and slope of the black matrix 42. The angle can be designed according to actual needs.

[0121] A first refractive index region 44 is disposed on a side of the color filter unit 41 away from the base substrate 11 to further converge the light emitted from the edge of the color filter unit 41 to prevent color mixing of the light of each sub-pixel.

[0122] Furthermore, a second refractive index region 45 is provided on the side of the color filter unit 41 away from the base substrate 11. The range of the orthographic projection of the second refractive index region 45 on the base substrate 11 should be smaller than the range of the orthographic projection of the color filter unit 41 on the base substrate 11. The second refractive index region 45 disperses the light emitted from the middle of the color filter unit 41, further compensating for the difference in light intensity between the edge and the middle of the color filter unit 41 and the inconsistency of the edge brightness of each sub-pixel. It should be noted that the refractive index of the first refractive index region is greater than the refractive index of the color filter unit, the refractive index of the second refractive index region is less than the refractive index of the color filter unit, and the material refractive index ratio is between 1.05 and 1.50.

[0123] Optionally, a microlens structure layer 46 is disposed on a side of the color filter unit 41 away from the base substrate 11 . The microlens 461 can be prepared by an etching process, and the material is transparent polyimide, photosensitive resin or the like.

[0124] In this embodiment, the light output angle of the light emitting layer 212 is greatly improved compared with the traditional structure. By changing the angle of the light, the intensity of the light emitted from the edge of the color filter unit is enhanced, the intensity of the light emitted from the middle of the color filter unit is dispersed, the intensity of the edge light is compensated, and the difference in light intensity between the edge and the middle of the color filter unit is reduced, thereby enhancing the symmetry and uniformity of the light emitted from the display substrate.

[0125] As used herein, the terms "substantially," "approximately," "approximately," and other similar terms are used as terms of approximation rather than as terms of degree, and they are intended to account for the inherent deviations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. Taking into account factors such as process fluctuations, measurement problems, and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system), "approximately" or "approximately" as used herein include the stated value and mean that the particular value is within an acceptable range of deviation as determined by one of ordinary skill in the art. For example, "approximately" can mean within one or more standard deviations, or within ±10% or ±5% of the stated value.

[0126] Although some embodiments according to the general inventive concept of the present disclosure have been illustrated and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the general inventive concept of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A display substrate, comprising: A backplane, comprising a base substrate and a driving circuit layer located on the base substrate; A light emitting device layer, located on a side of the driving circuit layer away from the base substrate, the light emitting device layer comprising a pixel defining layer and a light emitting element, the pixel defining layer defines a pixel opening, and at least a portion of the light emitting element is located at the pixel opening; A first encapsulation layer is located on a side of the light emitting device layer away from the substrate; as well as a color filter layer, located on a side of the first encapsulation layer away from the base substrate, the color filter layer comprising a color filter unit and a black matrix, Wherein, the display substrate further comprises: A reflective layer, the reflective layer is located on at least a portion of the side wall of the black matrix, the orthographic projection of the reflective layer on the base substrate is annular, and the orthographic projection of the reflective layer on the base substrate surrounds the orthographic projection of the color filter unit on the base substrate.

2. The display substrate according to claim 1, wherein: The orthographic projection of the light emitting element on the base substrate at least partially overlaps with the orthographic projection of the color filter unit on the base substrate, a plurality of the color filter units are arranged in an array, the black matrix separates the plurality of the color filter units, and the reflective layer is arranged in an array; and The reflective layer is configured to reflect at least a portion of the light emitted by the light emitting element and emit the light after passing through the color filter unit.

3. The display substrate according to claim 2, wherein: The material of the reflective layer includes metal or metal alloy; or the reflective layer includes an anti-reflective film; and / or, The thickness of the reflective layer is less than or equal to 1 μm.

4. The display substrate according to claim 1, wherein: The cross section of the black matrix parallel to the third direction is an inverted trapezoid; or The cross section of the black matrix along the third direction is in a convex shape, and the protruding portion of the convex shape is at least partially higher than the height of the cross section of the color filter unit along the third direction; The third direction is parallel to the light emitting direction of the base substrate.

5. The display substrate according to claim 1, wherein: The display substrate further comprises: a first refractive index region, the first refractive index region being located at a side of the color filter layer away from the base substrate, and an orthographic projection of the first refractive index region on the base substrate covering an orthographic projection of the reflective layer on the base substrate; and The refractive index of the first refractive index region is greater than the refractive index of the color filter unit, and the first refractive index region is configured to converge light.

6. The display substrate according to claim 5, wherein: The orthographic projection of the first refractive index region on the substrate is a ring structure, and the first refractive index regions are arranged in an array; and The orthographic projection of the first refractive index region on the base substrate partially overlaps with the orthographic projection of the color filter unit on the base substrate.

7. The display substrate according to claim 5, further comprising: a second refractive index region, the second refractive index region being located at a side of the color filter layer away from the base substrate, and an orthographic projection of the second refractive index region on the base substrate being located within an orthographic projection of the color filter unit on the base substrate; and The refractive index of the second refractive index region is smaller than the refractive index of the color filter unit, and the second refractive index region is configured to diverge light.

8. The display substrate according to claim 7, wherein: The second refractive index regions are arranged in an array, and the orthographic projection of the first refractive index region on the base substrate surrounds the orthographic projection of the second refractive index region on the base substrate.

9. The display substrate according to claim 1, further comprising: a microlens structure layer, the microlens structure layer being located on a side of the color filter layer away from the base substrate, the microlens structure layer comprising a plurality of microlenses and a filling layer covering the microlenses, the plurality of microlenses being arranged in a matrix, and the microlenses being configured to diverge light; and The orthographic projection of the microlens structure layer on the base substrate is located within the orthographic projection of the color filter unit on the base substrate.

10. The display substrate according to claim 9, wherein: The refractive index of the microlens is greater than the refractive index of the filling layer, and the microlens is a concave lens; and / or, The material of the microlens is selected from polyimide and photosensitive resin.

11. A display device, characterized in that: The invention comprises a display substrate according to any one of claims 1 to 10.

12. A method for preparing a display substrate, the method comprising the following steps: forming a driving circuit layer on the base substrate; A light emitting device layer is formed on a side of the driving circuit layer away from the base substrate, wherein: The light emitting device layer includes a pixel defining layer and a light emitting element, the pixel defining layer defines a pixel opening, and at least a portion of the light emitting element is located at the pixel opening; forming a first encapsulation layer on a side of the light emitting device layer away from the substrate; forming a black matrix on a side of the first encapsulation layer away from the base substrate; forming a reflective layer on at least a portion of the sidewalls of the black matrix, wherein the orthographic projection of the reflective layer on the base substrate is a ring; and A color filter unit is formed on a side of the first encapsulation layer away from the base substrate. The orthographic projection of the reflective layer on the base substrate surrounds the orthographic projection of the color filter unit on the base substrate.

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