Light-emitting substrate, display device and preparation method

Abstract

The invention discloses a light-emitting substrate, a display device and a preparation method. The light-emitting substrate comprises a substrate; the plurality of pixel units are arranged on the substrate in an array arrangement manner; the plurality of box dams are respectively arranged on the periphery of each pixel unit in a surrounding manner, and the box dams divide the substrate into a plurality of pixel areas provided with the pixel units and a black matrix area located on the periphery of the pixel areas; and the bottom black layer is arranged on the bottom black area. According to the light-emitting substrate, the box dams are arranged on the peripheries of the pixel units, the bottom black layer is prevented from making contact with the pixel units through the box dams, it is avoided that the bottom black layer makes contact with the pixel units to absorb light emitted by the pixel units, and the overall lighting effect of the light-emitting substrate can be improved; meanwhile, by arranging the box dam, the height of the bottom black layer relative to the substrate can be properly increased, it can be ensured that the blackness of the light-emitting substrate is kept consistent, the light-emitting substrate has relatively high blackness, the display effect of the light-emitting substrate is improved, and the requirements for light, thin, high-image-quality and high-dynamic display are met.

Description

Technical Field

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

[0002] As people pursue high-definition displays, the edge-type backlight MDL (light-emitting substrate) of traditional displays cannot meet the high-quality requirements such as high HDR (high dynamic lighting rendering) contrast, while the Direct-MDL (direct display light-emitting substrate) that can achieve high-quality images has a series of problems such as large thickness and weight. Mini LED (micro light-emitting diode) light-emitting substrate can well meet the needs of lightness and thinness and high-quality and high-dynamic display.

[0003] In related Mini LED direct display products, due to the differences in the light-emitting substrates, the blackness of the light-emitting substrates cannot be kept consistent after the film is applied. It takes a lot of manpower and time to test, classify and control, and there are defects such as low production efficiency, difficult quality control, and high production costs. If the substrate is pre-treated, a bottom black layer is formed on the substrate to keep the blackness of the light-emitting substrate consistent. However, in the related technology, the bottom black layer formed may not meet the blackness requirements, or has a greater impact on the light efficiency of the light-emitting substrate, or the efficiency of forming the bottom black layer is low, which cannot well meet the requirements of the light-emitting substrate for ink color and light efficiency.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The present application aims to at least to some extent solve the technical problem that the bottom black layer on the luminescent substrate cannot take into account both black and brightness. To this end, the present application provides a luminescent substrate, a display device and a preparation method.

[0006] An embodiment of the present application provides a light-emitting substrate, the light-emitting substrate comprising:

[0007] substrate;

[0008] A plurality of pixel units, wherein the plurality of pixel units are arranged in an array on the substrate;

[0009] A plurality of dams, each of which is respectively arranged around the periphery of each pixel unit, wherein the dams separate the substrate into a plurality of pixel regions where the pixel units are arranged and a bottom black region located around the pixel regions; and

[0010] A bottom black layer is disposed on the bottom black area.

[0011] In some embodiments, the dam surrounds the pixel unit on the substrate to form a closed ring;

[0012] The bottom black layer is arranged in contact with the dam.

[0013] In some embodiments, the dam includes at least one target dam, and the bottom black layer is in continuous contact with and surrounds the target dam.

[0014] In some embodiments, a height of the dam relative to the substrate is 5 μm to 15 μm smaller than a height of the pixel unit relative to the substrate.

[0015] In some embodiments, the height of the bottom black layer relative to the substrate is in the range of 10 μm to 60 μm, and the height of the bottom black layer relative to the substrate is at least 5 μm smaller than the height of the dam relative to the substrate.

[0016] In some embodiments, the area of ​​each pixel region is less than or equal to 3.125×10 4 μm 2 .

[0017] In some embodiments, the ratio of the total area of ​​the pixel regions to the total area of ​​the substrate is less than or equal to 0.02%.

[0018] In some embodiments, the pixel unit includes two sub-pixel units, and the light-emitting substrate includes a spacing dam, and the spacing dam is located between the sub-pixel units.

[0019] In some embodiments, the color of the dam includes at least one of black, white, and gray;

[0020] A cross-sectional shape of the dam perpendicular to the base includes at least one of a rectangle and a trapezoid.

[0021] In some embodiments, the dam includes a first dam layer and a second dam layer stacked together, and the first dam layer is located between the second dam layer and the substrate;

[0022] The color of the first dam layer is white; the color of the second dam layer is black or gray.

[0023] In some embodiments, the material of the dam includes a matrix and a dye located in the matrix.

[0024] In some embodiments, the matrix includes at least one of silica gel, epoxy resin, acrylic resin, polyimide resin, polyethylene resin, fluororesin, siloxane polymer resin, butyral resin, styrene-maleic acid copolymer, chlorinated polypropylene, polyurethane resin, phenolic resin, polyester resin, alkyd resin, styrene resin, polyamide resin, rubber resin, cyclized rubber, polybutadiene, benzoguanamine resin, melamine resin, and urea-formaldehyde resin; the colorant includes at least one of carbon black, manganese iron black, iron oxide black, copper chrome black, iron chrome black, iron black, cobalt black, antimony sulfide, and aniline black; or, the colorant includes at least one of titanium dioxide, zinc oxide, zinc sulfide, composite titanium white, zinc barium white, lead white, antimony white, and basic lead sulfate.

[0025] In some embodiments, the colorant has a mass content of 1.0% to 5.0% in the material of the dam.

[0026] In some embodiments, the light-emitting substrate further comprises:

[0027] A black film, the black film being located at a side of the pixel unit away from the substrate;

[0028] The black film completely covers the pixel area and covers at least a portion of the bottom black area.

[0029] The embodiment of the present application further provides a display device, the display device comprising the above-mentioned light-emitting substrate, the light-emitting substrate being a display substrate;

[0030] Among them, the pixel unit includes a plurality of sub-pixel units, and the sub-pixel unit includes an LED light-emitting chip, and the LED light-emitting chip is at least one of a mini-LED chip and a micro-LED chip.

[0031] The present application embodiment provides a method for preparing the above-mentioned light-emitting substrate, and the preparation method comprises the following steps:

[0032] providing a substrate;

[0033] Forming pixel units arranged in an array on the substrate;

[0034] forming a dam on the substrate;

[0035] A bottom black layer is formed on the substrate.

[0036] In some embodiments, the dam is formed on the substrate by three-dimensional printing technology; and the bottom black layer is formed on the bottom black area by three-dimensional printing technology or inkjet printing technology.

[0037] In some embodiments, the viscosity of the material of the dam is 200,000 cps to 500,000 cps.

[0038] The embodiments of the present application have at least the following beneficial effects:

[0039] The above-mentioned light-emitting substrate is provided with a dam around the pixel unit. The dam blocks the contact between the bottom black layer and the pixel unit, thereby preventing the bottom black layer from contacting the pixel unit to absorb the light emitted by the pixel unit, thereby improving the overall light efficiency of the light-emitting substrate. At the same time, by setting the dam, the height of the bottom black layer relative to the substrate can be appropriately increased, thereby ensuring that the blackness of the light-emitting substrate remains consistent and has a relatively high blackness, thereby improving the display effect of the light-emitting substrate and meeting the requirements of lightness, thinness, high-definition and high-dynamic display. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 A top view of a light-emitting substrate in an embodiment of the present application is shown;

[0042] Figure 2 Shows Figure 1 AA cross-sectional view of the light-emitting substrate;

[0043] Figure 3 Shows Figure 2 A cross-sectional view of the light-emitting substrate after being provided with a black film layer;

[0044] Figure 4 A top view of a light-emitting substrate in another embodiment of the present application is shown;

[0045] Figure 5 Shows Figure 4 A BB-direction cross-sectional view of the light-emitting substrate;

[0046] Figure 6 Shows Figure 5 A cross-sectional view of the light-emitting substrate after being provided with a black film layer;

[0047] Figure 7 A top view of a light-emitting substrate in another embodiment of the present application is shown;

[0048] Figure 8 Shows Figure 7 A CC cross-sectional view of the light-emitting substrate;

[0049] Fig. 9 Shows Figure 8 A cross-sectional view of the light-emitting substrate after being provided with a black film layer;

[0050] Fig.10 A cross-sectional view of a dam perpendicular to the substrate in an embodiment of the present application is shown;

[0051] Fig.11 A cross-sectional view of a dam perpendicular to the substrate in a light-emitting substrate in another embodiment of the present application is shown.

[0052] Reference numerals:

[0053] 100, substrate; 200, pixel unit; 210, first sub-pixel unit; 220, second sub-pixel unit; 230, third sub-pixel unit; 300, dam; 310, first dam layer; 320, second dam layer; 400, bottom black layer; 500, black film; H1, height of pixel unit relative to substrate; H2, height of dam relative to substrate; H3, height of bottom black layer relative to substrate. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides various specific examples of processes and materials, but those of ordinary skill in the art may recognize the application of other processes and / or the use of other materials.

[0056] The present application is described below with reference to the accompanying drawings and specific embodiments:

[0057] The present application embodiment provides a light-emitting substrate, such as Figures 1 to 9 As shown, the light-emitting substrate includes a substrate, a plurality of pixel units, a plurality of dams and a bottom black layer. The plurality of pixel units are arranged in an array on the substrate; the plurality of dams are respectively arranged around each pixel unit, and the dams separate the substrate into a plurality of pixel areas with pixel units and a bottom black area around the pixel areas; and the bottom black layer is arranged on the bottom black area.

[0058] The above-mentioned light-emitting substrate provided in the embodiment of the present application is provided with a dam around the pixel unit. The dam blocks the contact between the bottom black layer and the pixel unit, thereby preventing the bottom black layer from contacting the pixel unit to absorb the light emitted by the pixel unit, thereby improving the overall light efficiency of the light-emitting substrate. At the same time, by setting the dam, the height of the bottom black layer relative to the substrate can be appropriately increased, thereby ensuring that the blackness of the light-emitting substrate remains consistent and has a relatively high blackness, thereby improving the display effect of the light-emitting substrate and meeting the requirements of lightness, thinness, high-definition and high-dynamic display.

[0059] In the related art, the differences in the light-emitting substrates result in the blackness of the light-emitting substrates not being consistent after the film is applied. For example, the light-emitting substrate in which the LED chip is fixed on a glass substrate (Chip On Glass, COG) has different thickness tolerances and refractive indices of different functional layers on the substrate, resulting in the COG bare crystal light-emitting substrate having different colors such as yellowish / reddish. The blackness of the light-emitting substrate is inconsistent after the film is applied, and testing and classification control are required, which wastes a lot of manpower and material resources.

[0060] Through research, the present application has found that if the substrate is pre-treated and a bottom black layer is formed on the substrate, the blackness behind the peritoneum of the luminous substrate can be kept consistent. However, in the study, it was found that if a process of coating a photoresist material on the substrate and then forming a bottom black layer by exposure and development is adopted, the bottom black layer thickness that can be achieved by this process is less than 5μm, and the bottom black layer of this thickness range has no advantage over other processes in improving the blackness of the substrate. If a three-dimensional (3D) printing process is used to form a bottom black layer, there are the following two situations:

[0061] First, when using a bottom black layer material with a low viscosity, for example, the viscosity of the bottom black layer material is less than 100cps, the bottom black layer material printed by 3D printing will flow randomly and be filled between the LED chips by leveling. Due to the capillary effect, the bottom black layer material directly fills the gap between the LED chips, so that the bottom black layer material attached to the side wall of the LED chip is higher than the height of the bottom black layer. The light emitted by the side wall of the LED chip is absorbed by the bottom black layer material, resulting in the brightness of the light-emitting substrate with a bottom black layer being reduced by about 30% compared with the brightness of the light-emitting substrate without a bottom black layer. In other words, the light efficiency of the light-emitting substrate is lost by about 30%. In the later stage, a black film with a higher transmittance is required to supplement the light efficiency. However, the black film with a higher transmittance will result in a higher L value (brightness) of the blackness of the light-emitting substrate, which is not conducive to the overall appearance of the light-emitting substrate. In addition, when the bottom black layer material is attached to the side wall of the LED chip, the bottom black layer must not be damaged when the LED chip needs to be repaired or replaced during subsequent rework. Therefore, more precise operations are required to avoid damaging the bottom black layer. Otherwise, the bottom black layer needs to be filled again, which increases the complexity and difficulty of the process. For example, during rework laser repair, the laser focusing accuracy and energy need to be strictly controlled to avoid laser damage to the bottom black layer, which increases the difficulty of laser repair.

[0062] Secondly, use a bottom black layer material with a higher viscosity, for example, the viscosity of the bottom black layer material is greater than 100,000 cps. At this time, the bottom black layer material has a higher viscosity and better thixotropy. It can be formed after 3D printing, and there will be no leveling phenomenon, and it will not adhere to the side wall of the LED chip. However, more 3D printing times are required to fill the bottom black area between the pixel units, resulting in a lower efficiency in forming the bottom black layer and a greater increase in production costs. For example, the width of the bottom black area between the pixel units is about 800μm, and the width of a row of 3D printing is about 70μm. It takes 12 rows of 3D printing to form a bottom black layer on the bottom black area. The formation speed of the bottom black layer is low, which has a greater impact on the overall mass production of the light-emitting substrate. In addition, it is necessary to consider that there should be no gaps between two adjacent rows during 3D printing. Not only does it require high 3D printing accuracy, but if the two adjacent rows overlap, the thickness tolerance of the bottom black layer will be large, which will eventually affect the overall black consistency of the light-emitting substrate; if there is a gap between two adjacent rows, the blackness of the bottom black layer will be inconsistent, which will eventually affect the overall black consistency of the light-emitting substrate.

[0063] In response to the above-mentioned problems discovered by the research of the present application, the light-emitting substrate proposed in the present application has a dam arranged around the pixel unit, which can isolate the bottom black area from the pixel unit, so that when a bottom black layer is formed on the bottom black area, a bottom black layer material with a lower viscosity can be used to improve the formation efficiency of the bottom black layer and the consistency of the blackness of the bottom black layer; at the same time, it can also avoid the bottom black layer material from contacting the LED chip of the pixel unit, reducing the light efficiency loss caused by the side wall light of the LED chip being absorbed by the bottom black layer; in addition, if a defective LED chip needs to be reworked and repaired, a laser can be used to remove the original damaged and positioned LED chip. At this time, since there is no bottom black layer material attached to the side wall of the LED chip, that is, the side wall of the LED chip is not in contact with the bottom black layer, the laser will not damage the bottom black layer, and there is no need to replenish the bottom black layer for a second time, thereby reducing the requirements for laser accuracy and reducing the process complexity and difficulty of rework and repair.

[0064] As an optional implementation, Figures 1 to 9 As shown, the dam surrounds the pixel unit on the substrate to form a closed ring; the bottom black layer is arranged in contact with the dam.

[0065] In some embodiments, Figures 1 to 9 As shown, the dam is formed on the substrate around the pixel unit to form a closed ring, and the pixel unit can be completely isolated from the bottom black layer by the dam, so as to avoid the bottom black layer material contacting with the pixel unit and adhering to the side wall of the LED chip during the process of forming the bottom black layer, thereby affecting the light efficiency of the light-emitting substrate. At the same time, the bottom black layer is arranged in contact with the dam, so as to avoid the existence of a gap between the bottom black layer and the dam, which affects the uniformity of the overall blackness of the light-emitting substrate.

[0066] As an optional implementation, Figures 1 to 9 As shown, the dam includes at least one target dam, and the bottom black layer is in continuous contact with the target dam and is arranged around it.

[0067] In some embodiments, Figures 1 to 9 As shown, the bottom black layer is in continuous contact with the target dam and is arranged around it, which can ensure that the area outside the pixel area is completely covered by the target dam or the bottom black layer, thereby ensuring that the area on the substrate except the pixel area is black, so as to improve the overall blackness of the light-emitting substrate.

[0068] As an optional implementation, Figures 1 to 9 As shown, the height of the dam relative to the substrate is 5 μm to 15 μm smaller than the height of the pixel unit relative to the substrate.

[0069] In some embodiments, Figure 2 As shown, the height of the dam relative to the substrate is the height from the top surface of the dam to the substrate, and the height of the pixel unit relative to the substrate is the height from the top surface of the pixel unit to the substrate.

[0070] In some embodiments, the preparation tolerance of the dam is considered so that the height of the dam relative to the substrate is 5μm to 15μm less than the height of the pixel unit relative to the substrate, that is, on the substrate, the height of the dam is 5μm to 15μm lower than the height of the pixel unit. The dam is a structure that blocks the bottom black layer. If the height of the dam is low, the corresponding height of the bottom black layer is also low, and the blackness of the bottom black layer cannot meet the blackness requirements of the light-emitting substrate; if the height of the dam is high, exceeding the height of the pixel unit relative to the substrate, the highest point on the light-emitting substrate is the dam, and after the black film is attached, the black film above the pixel unit will be lower, the transmittance will be reduced, and the power consumption of the light-emitting substrate will be increased. Taking the above reasons into consideration, making the dam 5μm to 15μm lower than the pixel unit can not only avoid the reduction of transmittance due to the excessive thickness of the black film above the pixel unit, but also increase the thickness of the bottom black layer as much as possible, thereby improving the overall blackness of the light-emitting substrate and improving the appearance of the light-emitting substrate.

[0071] As an optional implementation, Figures 1 to 9 As shown, the height of the bottom black layer relative to the substrate is in the range of 10 μm to 60 μm, and the height of the bottom black layer relative to the substrate is more than 5 μm smaller than the height of the dam relative to the substrate.

[0072] In some embodiments, Figure 2 As shown, the height of the bottom black layer relative to the substrate is the height from the top surface of the bottom black layer to the substrate.

[0073] In some embodiments, the bottom black layer is mainly used to improve the blackness of the light-emitting substrate. Therefore, the higher the blackness of the bottom black layer, the better, and the thicker the bottom black layer, the better. However, the thickness of the bottom black layer should not exceed the thickness of the dam. At the same time, it is also necessary to comprehensively consider the cost of preparing the bottom black layer and the maximum blackness that the bottom black layer can achieve. If the blackness of the bottom black layer material is relatively large, the height of the bottom black layer relative to the substrate can be appropriately reduced to reduce the preparation cost of the bottom black layer and improve the preparation effect of the bottom black layer; if the blackness of the bottom black layer material is relatively small, the height of the bottom black layer relative to the substrate can be appropriately increased to ensure that the blackness of the bottom black layer meets the blackness requirements of the light-emitting substrate. Therefore, based on the above reasons, the height of the bottom black layer relative to the substrate can be made within the range of 10μm to 60μm. The height of the bottom black layer relative to the substrate within this range improves the blackness of the bottom black layer, thereby improving the overall blackness of the light-emitting substrate, while having little effect on the preparation difficulty and preparation cost of the bottom black layer.

[0074] In some embodiments, considering the manufacturing tolerance, the height of the bottom black layer relative to the substrate is made smaller than the height of the dam relative to the substrate by more than 5 μm, which ensures that the bottom black layer will not go over the dam and contact the side of the LED chip in the pixel unit.

[0075] As an optional implementation, Figures 1 to 9 As shown, the area of ​​each pixel is less than or equal to 3.125×10 4 μm 2 .

[0076] In some embodiments, Figure 1 and Figure 4 As shown in the figure, the pixel area can be regarded as the window part on the substrate. Although the pixel area is not covered by the bottom black layer, the area of ​​each pixel area is less than or equal to 3.125×10 4 μm 2 That is to say, the area of ​​each pixel area is smaller than that of the bottom black area, and the pixel area has little effect on the blackness of the light-emitting substrate, which can ensure that the blackness of the base meets the blackness requirements of the light-emitting substrate.

[0077] As an optional implementation, Figures 1 to 9 As shown, the ratio of the total area of ​​the pixel regions to the total area of ​​the substrate is less than or equal to 0.02%.

[0078] For example, the pixel unit of the pixel area is arranged on the substrate through the pad, and the LED chip of each pixel unit is arranged on the substrate through two pads. The area of ​​the two pads is 125μm×125μm×2. The area of ​​the LED chip of each pixel unit is smaller than the area of ​​the two pads. The dam is arranged around the two pads. Therefore, the area of ​​the two pads can be regarded as the area of ​​a single pixel area, which is 3.125×10 4 μm 2. Compared with the entire light-emitting substrate, the area of ​​a single pixel area is relatively small, and the effect on the blackness of the light-emitting substrate can be ignored. At the same time, the spacing between the LED chips of each pixel unit is fixed, generally 1.25mm = 12500μm, then the substrate area allocated to the LED chip of each pixel unit is 12500μm × 12500μm, that is, the substrate area corresponding to each pixel area is 12500μm × 12500μm, then the ratio of a single pixel area to the corresponding substrate area is 0.02%, that is, the ratio of the total area of ​​the pixel area to the total area of ​​the substrate is 0.02%, and the total area of ​​the pixel area is relatively small, so the overall effect of the pixel area on the blackness of the light-emitting substrate is also small. Since the area of ​​a single pixel area is relatively small, and the total area of ​​the pixel area is relatively small relative to the total area of ​​the substrate, from a visual observation point of view, the overall difference between the blackness of the black film corresponding to the pixel area and the total blackness of the black film and the bottom black layer corresponding to the bottom black area is not obvious, and the overall effect on the overall appearance of the light-emitting substrate is small and can be ignored.

[0079] As an optional implementation, Figure 4 and Figure 6 As shown, the pixel unit includes two sub-pixel units, and the light-emitting substrate includes a spacing dam, which is located between the sub-pixel units.

[0080] In some embodiments, sub-pixel units can be separated by a spacing dam, and the spacing dam can block light emitted from the side wall of the pixel unit from entering the adjacent sub-pixel unit area, thereby avoiding cross-color between the sub-pixel units. The spacing dam has a simple structure and can be formed on a substrate together with the dam, thereby saving the preparation cost of the spacing dam.

[0081] In some embodiments, Figure 4 and Figure 6 As shown, the pixel unit may include three sub-pixel units, namely a first sub-pixel unit, a second sub-pixel unit and a third sub-pixel unit. The first sub-pixel unit, the second sub-pixel unit and the third sub-pixel unit may respectively emit red, green and blue light. The light emitted by the three sub-pixel units may be mixed on the light emitting side of the light emitting substrate to produce different colors that need to be displayed.

[0082] As an optional implementation, Figures 1 to 9 As shown, the color of the dam includes at least one of black, white, and gray; the cross-sectional shape of the dam perpendicular to the substrate includes at least one of a rectangle and a trapezoid.

[0083] In some embodiments, the color of the dam can be black or gray. When the color of the dam is black or gray, the color of the dam can be closer to the color of the bottom black layer, so that the dam and the bottom black layer form an integral bottom black structure, thereby improving the overall blackness of the light-emitting substrate. At the same time, since the dam and the bottom black layer improve the overall blackness of the light-emitting substrate, the transmittance of the black film can be improved, so that the light efficiency of the light-emitting substrate is higher.

[0084] In some embodiments, the color of the dam can be white. When the color of the dam is white, the white dam can reflect the light emitted from the side wall of the LED chip, increase the luminous flux emitted by the LED chip, and improve the light efficiency of the light-emitting substrate. At the same time, the blackness of the black film can be increased and the transmittance of the black film can be reduced, so that the overall blackness of the light-emitting substrate can be improved while the light efficiency of the light-emitting substrate is improved.

[0085] In some embodiments, Fig.10 and Fig.11 As shown, the cross-sectional shape of the dam perpendicular to the substrate includes at least one of a rectangle and a trapezoid. The dam can be formed on the substrate by printing once, or it can be formed on the substrate layer by layer by printing multiple times. According to the printing control accuracy and the characteristics of the dam material, the cross-sectional shape of the dam perpendicular to the substrate can be a rectangle, a trapezoid, or a combination of a rectangle and a trapezoid. If the viscosity and thixotropy of the dam material are high, the shape of the printed dam can remain unchanged, and the dam is closer to a regular cuboid, as shown in Fig.10 As shown in FIG. 1 , the cross-sectional shape of the dam perpendicular to the substrate is a rectangle; if the viscosity and thixotropy of the dam material are relatively low, after the dam is formed by multiple printings, the dam portion formed by the first printing may collapse slightly due to the extrusion, and the dam is a trapezoidal body. Fig.11 As shown, the cross-sectional shape of the dam perpendicular to the base is close to a rectangle.

[0086] As an optional implementation, Figures 7 to 9 As shown, the dam includes a first dam layer and a second dam layer which are stacked, and the first dam layer is located between the second dam layer and the substrate; wherein the first dam layer is white in color; and the second dam layer is black or gray in color.

[0087] In some embodiments, Figures 7 to 9 As shown, the dam adopts a double-layer structure, wherein the first dam layer is located between the second dam layer and the substrate, so that the color of the first dam layer is white, and the light emitted from the side wall of the LED chip can be reflected by the white dam part, thereby improving the light efficiency of the LED chip. The second dam layer covers the first dam layer and is closer to the display side of the light-emitting substrate, so that the color of the second dam layer is black, and a relatively uniform bottom black structure can be formed by the black dam part and the bottom black layer to improve the overall blackness of the light-emitting substrate.

[0088] In some embodiments, the height of the first dam layer and the second dam layer can be determined according to the printing control accuracy. Optionally, the larger the height ratio of the first dam layer to the second dam layer, the better. The closer the height of the second dam layer is to the height of the bottom black layer, the better.

[0089] As an optional embodiment, the material of the dam includes a matrix and a dye in the matrix.

[0090] In some embodiments, the material of the dam includes a matrix and a dye in the matrix, and the dye is evenly distributed in the matrix so that the matrix can display a preset color of the dam. For example, a black dye can be added to the matrix so that the dam formed by the material of the dam appears black. For another example, a white dye can be added to the matrix so that the dam formed by the material of the dam appears white.

[0091] As an optional embodiment, the matrix includes at least one of silica gel, epoxy resin, acrylic resin, polyimide resin, polyethylene resin, fluororesin, siloxane polymer resin, butyral resin, styrene-maleic acid copolymer, chlorinated polypropylene, polyurethane resin, phenolic resin, polyester resin, alkyd resin, styrene resin, polyamide resin, rubber resin, cyclized rubber, polybutadiene, benzoguanamine resin, melamine resin, and urea-formaldehyde resin; the colorant includes at least one of carbon black, manganese iron black, iron oxide black, copper chrome black, iron chrome black, iron black, cobalt black, antimony sulfide, and aniline black, or the colorant includes at least one of titanium dioxide, zinc oxide, zinc sulfide, composite titanium white, zinc barium white, lead white, antimony white, and basic lead sulfate.

[0092] In some embodiments, among the materials of the dam, the type of the matrix can be adaptively selected according to the structure, strength and preparation method of the dam.

[0093] In some embodiments, when the color of the dam is black, the colorant may be selected from at least one of carbon black, manganese iron black, iron oxide black, copper chrome black, iron chrome black, iron black, cobalt black, antimony sulfide, and aniline black to make the dam appear black; in some embodiments, when the color of the dam is white, the colorant may be selected from at least one of titanium dioxide, zinc oxide, zinc sulfide, composite titanium dioxide, zinc barium white, lead white, antimony white, and basic lead sulfate to make the dam appear white; in some embodiments, when the color of the dam is gray, the colorant in the material of the dam may include a black colorant and a white colorant, and the dam appears gray through a combination of the black colorant and the white colorant.

[0094] As an optional implementation, the material of the dam includes a matrix and a dye in the matrix, and the mass content of the dye is 1.0% to 5.0%.

[0095] In some embodiments, the colorant is located in the matrix of the material of the dam so that the dam presents the color of the colorant. The mass content of the colorant in the material of the dam is related to the color depth of the dam. When the mass content of the colorant in the material of the dam is 1.0% to 5.0%, the color of the dam can be made to present the corresponding color, avoiding the color of the dam not meeting the design requirements due to too little colorant, and avoiding the defect of uneven color of the dam caused by the agglomeration of the colorant in the matrix due to too much colorant. Optionally, the mass content of the colorant in the material of the dam is 2.0% to 3.5%, so that the color and color uniformity of the dam can meet the design requirements of the dam, and effectively avoid the agglomeration of the colorant in the matrix, and avoid the smoothness of printing affected by the agglomeration of the colorant, which can effectively avoid the clogging of the material of the dam during the printing process.

[0096] As an optional implementation, Figures 1 to 9 As shown, the light-emitting substrate also includes:

[0097] A black film, which is located on a side of the pixel unit away from the substrate;

[0098] The black mask completely covers the pixel area and covers at least a portion of the bottom black area.

[0099] In some embodiments, Figures 1 to 9 As shown, the black film is located on the side of the pixel unit away from the substrate, so that the black film can completely cover the pixel area and cover at least part of the bottom black area. The black film can improve the transmittance of the light-emitting substrate and the uniformity of the overall blackness, thereby improving the appearance of the light-emitting substrate. In the above embodiment, since the dam and the bottom black layer are provided on the substrate, the bottom black layer can improve the blackness of the light-emitting substrate. Therefore, the blackness and transmittance of the black film can be appropriately adjusted according to the blackness of the bottom black layer. While ensuring that the light-emitting substrate has good blackness, the light efficiency of the light-emitting substrate is further improved, thereby improving the comprehensive performance of the light-emitting substrate.

[0100] Based on the same inventive concept, an embodiment of the present application also provides a display device, which includes the above-mentioned light-emitting substrate, and the light-emitting substrate is a display substrate; wherein the pixel unit includes a plurality of sub-pixel units, and the sub-pixel unit includes an LED light-emitting chip, and the LED light-emitting chip is at least one of a mini-LED chip and a micro-LED chip.

[0101] Since the display device provided by the present invention includes the light-emitting substrate of the above technical solution, the display device provided by the present invention has all the beneficial effects of the above light-emitting substrate, which will not be described in detail here.

[0102] Based on the same inventive concept, the embodiment of the present application further provides a method for preparing the above-mentioned light-emitting substrate, and the method for preparing the light-emitting substrate comprises the following steps:

[0103] providing a substrate;

[0104] Forming pixel units arranged in an array on a substrate;

[0105] Forming a dam on the substrate;

[0106] A bottom black layer is formed on the substrate.

[0107] In the preparation method of the light-emitting substrate proposed in the present application, a dam is formed on the substrate through a line, and the dam is arranged around the periphery of each pixel unit, so that the pixel unit can be isolated from the bottom black area, so that a bottom black layer can be formed on the bottom black area more conveniently, and the restrictions on the bottom black layer material and the formation method are reduced. The bottom black layer material with relatively low viscosity can be used, which reduces the difficulty of forming the bottom black layer, increases the speed of forming the bottom black layer, and then improves the formation efficiency of the bottom black layer, and at the same time can reduce the adverse effects of the bottom black layer on the pixel unit.

[0108] In some embodiments, after forming the bottom black layer on the substrate, the method for preparing the light-emitting substrate further comprises the following steps:

[0109] A black film is formed on the pixel unit, the dam and the side of the bottom black layer away from the substrate.

[0110] In the above embodiment, the black film is formed on the side of the pixel unit, the dam and the bottom black layer away from the substrate, so that the black film can completely cover the pixel area and cover at least part of the bottom black area. The black film can improve the transmittance of the light-emitting substrate and the uniformity of the overall blackness, thereby enhancing the appearance of the light-emitting substrate.

[0111] In some embodiments, the black film is removable. After the black film is formed in the light-emitting substrate, if the LED chip is repaired, the black film can be removed by heating, and then the broken LED chip can be removed by laser. At this time, since the side of the LED chip is isolated from the bottom black layer, there is no bottom black layer material on the side of the LED chip. Therefore, when the broken LED chip is removed by laser, the bottom black layer will not be damaged, so there is no need to form the bottom black layer again. After modifying the LED chip, a new black film can be formed again.

[0112] As an optional implementation, the dam is formed on the substrate by three-dimensional printing technology; and the bottom black layer is formed on the bottom black area by three-dimensional printing technology or inkjet printing technology.

[0113] In some embodiments, the dam can be formed on the substrate by three-dimensional printing technology. For example, a circle of dam is printed around the pixel unit by three-dimensional printing technology. The dam can be formed on the substrate by one layer of printing or by multiple layers of printing.

[0114] In some embodiments, the bottom black layer can be formed on the bottom black area by three-dimensional printing technology or inkjet printing technology. The bottom black layer material can be made of a material with relatively low viscosity so that the bottom black layer material has a certain leveling layer, thereby improving the formation efficiency of the bottom black layer, improving production efficiency, and reducing production costs.

[0115] As an optional implementation manner, the viscosity of the material of the dam is 200,000 cps to 500,000 cps.

[0116] In some embodiments, the viscosity of the dam material is set to 200,000 cps to 500,000 cps, which can ensure that the dam formed after 3D printing maintains the printed shape, avoid excessive fluidity of the dam material contacting the side wall of the pixel unit and affecting the luminous efficiency of the pixel unit, and also prevent the dam from being deformed by force.

[0117] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0118] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0119] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A light-emitting substrate, characterized in that: The light-emitting substrate comprises: substrate; A plurality of pixel units, wherein the plurality of pixel units are arranged in an array on the substrate; A plurality of dams, each of which is respectively arranged around the periphery of each pixel unit, wherein the dams separate the substrate into a plurality of pixel regions where the pixel units are arranged and a bottom black region located around the pixel regions; and A bottom black layer is disposed on the bottom black area.

2. The light-emitting substrate according to claim 1, wherein: The dam surrounds the pixel unit on the substrate to form a closed ring; The bottom black layer is arranged in contact with the dam.

3. The light-emitting substrate according to claim 2, characterized in that: The dam includes at least one target dam, and the bottom black layer is in continuous contact with and surrounding the target dam.

4. The light-emitting substrate according to claim 1, wherein: A height of the dam relative to the substrate is 5 μm to 15 μm smaller than a height of the pixel unit relative to the substrate.

5. The light-emitting substrate according to claim 4, characterized in that: The height of the bottom black layer relative to the substrate is in the range of 10 μm to 60 μm, and the height of the bottom black layer relative to the substrate is at least 5 μm smaller than the height of the dam relative to the substrate.

6. The light-emitting substrate according to claim 1, wherein: The area of ​​each pixel region is less than or equal to 3.125×10 4 μm 2 .

7. The light-emitting substrate according to claim 1, wherein: The ratio of the total area of ​​the pixel regions to the total area of ​​the substrate is less than or equal to 0.02%.

8. The light-emitting substrate according to any one of claims 1 to 7, characterized in that: The pixel unit includes two sub-pixel units, and the light-emitting substrate includes a spacing dam, and the spacing dam is located between the sub-pixel units.

9. The light-emitting substrate according to any one of claims 1 to 7, characterized in that: The color of the dam includes at least one of black, white and gray; A cross-sectional shape of the dam perpendicular to the base includes at least one of a rectangle and a trapezoid.

10. The light-emitting substrate according to any one of claims 1 to 7, characterized in that: The dam comprises a first dam layer and a second dam layer which are stacked, and the first dam layer is located between the second dam layer and the substrate; The color of the first dam layer is white; the color of the second dam layer is black or gray.

11. The light-emitting substrate according to any one of claims 1 to 7, characterized in that: The material of the dam includes a matrix and a dye located in the matrix.

12. The light emitting substrate according to claim 11, wherein: The matrix includes at least one of silica gel, epoxy resin, acrylic resin, polyimide resin, polyethylene resin, fluororesin, siloxane polymer resin, butyral resin, styrene-maleic acid copolymer, chlorinated polypropylene, polyurethane resin, phenolic resin, polyester resin, alkyd resin, styrene resin, polyamide resin, rubber resin, cyclized rubber, polybutadiene, benzoguanamine resin, melamine resin, and urea-formaldehyde resin; the colorant includes at least one of carbon black, manganese iron black, iron oxide black, copper chrome black, iron chrome black, iron black, cobalt black, antimony sulfide, and aniline black, or the colorant includes at least one of titanium dioxide, zinc oxide, zinc sulfide, composite titanium white, zinc barium white, lead white, antimony white, and basic lead sulfate.

13. The light emitting substrate according to claim 11, wherein: The mass content of the dye in the material of the dam is 1.0% to 5.0%.

14. The light-emitting substrate according to any one of claims 1 to 7, characterized in that: The light-emitting substrate further comprises: A black film, the black film being located at a side of the pixel unit away from the substrate; The black film completely covers the pixel area and covers at least a portion of the bottom black area.

15. A display device, characterized in that: The display device comprises the light-emitting substrate according to any one of claims 1 to 14, wherein the light-emitting substrate is a display substrate; Among them, the pixel unit includes a plurality of sub-pixel units, and the sub-pixel unit includes an LED light-emitting chip, and the LED light-emitting chip is at least one of a mini-LED chip and a micro-LED chip.

16. A method for preparing a light-emitting substrate according to any one of claims 1 to 14, characterized in that: The preparation method comprises the following steps: providing a substrate; Forming pixel units arranged in an array on the substrate; forming a dam on the substrate; A bottom black layer is formed on the substrate.

17. The preparation method according to claim 16, characterized in that: The dam is formed on the substrate by three-dimensional printing technology; the bottom black layer is formed on the bottom black area by three-dimensional printing technology or inkjet printing technology.

18. The preparation method according to claim 16, characterized in that: The viscosity of the material of the dam is 200000cps to 500000cps.

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