Fabrication method of display substrate, display substrate and display device

Abstract

The manufacturing method of a display substrate, the display substrate, and the display device provided by the present disclosure can take into account the film thickness uniformity of the light-emitting functional layer in different color sub-pixel regions, ensure the effective aperture ratio of different color sub-pixel regions, and improve the device lifespan. The manufacturing method includes: providing a substrate, where the substrate includes a plurality of sub-pixel regions of different colors; printing a solution of the light-emitting functional layer in each sub-pixel region, where the volume of the solution in different color sub-pixel regions has a positive correlation with the saturated vapor pressure of the solution; and performing vacuum drying on the solution to form a light-emitting functional layer with uniform film thickness.

Description

Technical Field

[0001] The present disclosure relates to the field of display technologies, and particularly to a method for manufacturing a display substrate, a display substrate, and a display device. Background Art

[0002] As a new type of light-emitting device, organic electroluminescent devices (OLEDs) have shown great application potential in the fields of display and lighting, and thus have received strong attention from the academic and industrial communities. In the field of display, organic electroluminescent devices have the advantages of self-luminescence, fast response, wide viewing angle, high brightness, vivid colors, light weight, etc. compared with liquid crystal display devices (LCDs), and are considered to be the next-generation display technology. Summary of the Invention

[0003] The method for manufacturing a display substrate, the display substrate, and the display device provided by the embodiments of the present disclosure are specifically as follows:

[0004] On the one hand, an embodiment of the present disclosure provides a method for manufacturing a display substrate, including:

[0005] Providing a substrate, where the substrate includes a plurality of sub-pixel regions of different colors;

[0006] Printing a solution of a light-emitting functional layer in each of the sub-pixel regions, where the volume of the solution in the sub-pixel regions of different colors has a positive correlation with the saturated vapor pressure of the solution;

[0007] Performing vacuum drying on the solution to form the light-emitting functional layer with a uniform film thickness.

[0008] Optionally, in the above manufacturing method provided by the embodiment of the present disclosure, the solution includes a mutually soluble first solvent and a second solvent, and the saturated vapor pressure of the first solvent is less than that of the second solvent.

[0009] Optionally, in the above manufacturing method provided by the embodiment of the present disclosure, the sub-pixel regions include: a plurality of red sub-pixel regions, a plurality of green sub-pixel regions, and a plurality of blue sub-pixel regions;

[0010] Printing the solution of the light-emitting functional layer in the plurality of sub-pixel regions specifically includes:

[0011] Printing a first solution of the light-emitting functional layer in the plurality of red sub-pixel regions, printing a second solution of the light-emitting functional layer in the plurality of green sub-pixel regions, and printing a third solution of the light-emitting functional layer in the plurality of blue sub-pixel regions; where the volume of the second solution is greater than or equal to the volume of the third solution and less than or equal to the volume of the first solution, and the saturated vapor pressure of the second solution is greater than or equal to the saturated vapor pressure of the third solution and less than or equal to the saturated vapor pressure of the first solution.

[0012] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, the ratio of the saturated vapor pressure of the first solution, the saturated vapor pressure of the second solution, and the saturated vapor pressure of the third solution is (2.5-1):(2.5-1):1.

[0013] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, the volume ratio of the first solvent in the first solution, the second solution, and the third solution increases in sequence, and the volume ratio of the second solvent in the first solution, the second solution, and the third solution decreases in sequence.

[0014] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, in the first solution, the volume ratio of the first solvent is 5%-30%, and the volume ratio of the second solvent is 70%-95%;

[0015] In the second solution, the volume ratio of the first solvent is 30%-60%, and the volume ratio of the second solvent is 40%-70%;

[0016] In the third solution, the volume ratio of the first solvent is 60%-95%, and the volume ratio of the second solvent is 5%-40%.

[0017] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, the first solvent is one or any combination of cumene, cymene, 1,3,5-trimethylbenzene, dimethylanisole, and p-diethylbenzene, and the second solvent is one or any combination of chlorobenzene, cyclohexanone, and o-xylene.

[0018] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, when the light-emitting functional layer is a hole injection layer or a light-emitting material layer, the volume of the second solution is greater than the volume of the third solution and less than the volume of the first solution; when the light-emitting functional layer is a hole transport layer, the volume of the second solution is greater than or equal to the volume of the third solution and less than or equal to the volume of the first solution.

[0019] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, when the light-emitting functional layer is a hole injection layer or a hole transport layer, the concentrations of the first solution, the second solution, and the third solution are the same; when the light-emitting functional layer is a light-emitting material layer, the concentration of the first solution is greater than or equal to the concentration of the third solution and less than or equal to the concentration of the second solution.

[0020] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, after providing a substrate and before printing the solution of the light-emitting functional layer in the plurality of sub-pixel regions, it further includes:

[0021] A pixel defining layer is formed on the substrate, and the pixel defining layer has a first pixel opening in the red sub-pixel region, a second pixel opening in the green sub-pixel region, and a third pixel opening in the blue sub-pixel region;

[0022] The area of the third pixel opening is smaller than the area of the second pixel opening and larger than the area of the first pixel opening.

[0023] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, the plurality of green sub-pixel regions include: a plurality of first-class green sub-pixel regions and a plurality of second-class green sub-pixel regions;

[0024] The area of the second pixel opening corresponding to the first-class green sub-pixel region is larger than the area of the second pixel opening corresponding to the second-class green sub-pixel region;

[0025] The saturated vapor pressure of the second solution corresponding to the first-class green sub-pixel region is less than the saturated vapor pressure of the second solution corresponding to the second-class green sub-pixel region.

[0026] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, the ratio of the saturated vapor pressure of the first solution, the saturated vapor pressure of the second solution corresponding to the first-class green sub-pixel region, the saturated vapor pressure of the second solution corresponding to the second-class green sub-pixel region, and the saturated vapor pressure of the third solution is 1.746:1.404:1.378:1.

[0027] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, after providing a substrate and before forming the pixel defining layer on the substrate, it further includes:

[0028] Forming a plurality of first electrodes in the plurality of sub-pixel regions.

[0029] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, after vacuum drying the solution to form the light-emitting functional layer with uniform film thickness, it further includes:

[0030] Sequentially forming an electron transport layer, an electron injection layer, and a second electrode on the light-emitting functional layer.

[0031] On the other hand, the embodiments of the present disclosure provide a display substrate, including:

[0032] A substrate having a plurality of sub-pixel regions with different light-emitting colors;

[0033] A pixel defining layer located above the substrate, and the pixel defining layer has pixel openings in each of the sub-pixel regions;

[0034] The light-emitting functional layer is located on the side of the pixel defining layer away from the substrate. At least part of the light-emitting functional layer is located within the pixel opening. The light-emitting functional layer includes a central region away from the pixel defining layer, a climbing region in contact with the pixel defining layer, and a transition region between the central region and the climbing region.

[0035] In a direction perpendicular to the substrate, the difference between the thickness of the light-emitting functional layer in the central region and the target thickness of the light-emitting functional layer is less than or equal to 5 nm, the difference between the thickness of the light-emitting functional layer in the transition region and the target thickness of the light-emitting functional layer is greater than 5 nm and less than or equal to 20 nm, and the difference between the thickness of the light-emitting functional layer in the climbing region and the target thickness of the light-emitting functional layer is greater than 20 nm.

[0036] Optionally, in the above display substrate provided by the embodiments of the present disclosure, 70%-90% of the entire projected area radiating outward from the center of the light-emitting functional layer and having a shape contour substantially the same as that of the pixel opening is the central region, 0%-5% of the entire projected area covering the pixel defining layer and having a shape contour substantially the same as that of the pixel opening is the climbing region, and 5%-30% of the entire projected area between the climbing region and the central region and having a shape contour substantially the same as that of the pixel opening is the transition region.

[0037] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the thickness uniformity of the light-emitting functional layer within the pixel opening has a positive correlation with the area of the pixel opening.

[0038] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the sub-pixel region includes a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region. The pixel opening includes a first pixel opening located in the first sub-pixel region, a second pixel opening located in the second sub-pixel region, and a third pixel opening located in the third sub-pixel region. The area of the third pixel opening is greater than the area of the first pixel opening and less than the area of the second pixel opening.

[0039] The light-emitting functional layer includes a hole injection layer, a hole transport layer, and a light-emitting material layer. The thickness uniformity of the hole injection layer increases in sequence within the first pixel opening, within the third pixel opening, and within the second pixel opening. The thickness uniformity of the hole transport layer increases in sequence within the first pixel opening, within the third pixel opening, and within the second pixel opening. The thickness uniformity of the light-emitting material layer increases in sequence within the first pixel opening, within the third pixel opening, and within the second pixel opening.

[0040] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the sub-pixel region includes a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region, and the light-emitting functional layer includes a hole injection layer, a hole transport layer, and a light-emitting material layer;

[0041] The average thickness of the hole injection layer in the first sub-pixel region is 40 nm - 50 nm, the average thickness in the second sub-pixel region is 40 nm - 50 nm, and the average thickness in the third sub-pixel region is 30 nm - 40 nm;

[0042] The average thickness of the hole transport layer in the first sub-pixel region is 20 nm - 28 nm, the average thickness in the second sub-pixel region is 20 nm - 27 nm, and the average thickness in the third sub-pixel region is 20 nm - 27 nm;

[0043] The average thickness of the light-emitting material layer in the first sub-pixel region is 120 nm - 135 nm, the average thickness in the second sub-pixel region is 80 nm - 95 nm, and the average thickness in the third sub-pixel region is 60 nm - 72 nm.

[0044] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the luminous efficiency of the first sub-pixel region is 11.5 Cd / A - 15.6 Cd / A, the luminous efficiency of the second sub-pixel region is 35.1 Cd / A - 41.2 Cd / A, and the luminous efficiency of the third sub-pixel region is 33 Cd / A - 46 Cd / A.

[0045] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the sub-pixel region includes a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region, and the light-emitting functional layer includes a hole injection layer, a hole transport layer, and a light-emitting material layer;

[0046] The average thickness of the hole injection layer in the first sub-pixel region is 12 nm - 20 nm, the average thickness in the second sub-pixel region is 6 nm - 12 nm, and the average thickness in the third sub-pixel region is 6 nm - 12 nm;

[0047] The average thickness of the hole transport layer in the first sub-pixel region is 21 nm - 30 nm, the average thickness in the second sub-pixel region is 16 nm - 26 nm, and the average thickness in the third sub-pixel region is 11 nm - 20 nm;

[0048] The average thickness of the light-emitting material layer in the first sub-pixel region is 87 nm - 105 nm, the average thickness in the second sub-pixel region is 63 nm - 78 nm, and the average thickness in the third sub-pixel region is 55 nm - 70 nm.

[0049] Optionally, in the above-mentioned display substrate provided by the embodiments of the present disclosure, the luminous efficiency of the first sub-pixel region is 16.8 Cd / A - 20.3 Cd / A, the luminous efficiency of the second sub-pixel region is 36.5 Cd / A - 49.5 Cd / A, and the luminous efficiency of the third sub-pixel region is 32.4 Cd / A - 47.2 Cd / A.

[0050] Optionally, in the above-mentioned display substrate provided by the embodiments of the present disclosure, it further includes: an electron transport layer, an electron injection layer, and a second electrode sequentially disposed on a side of the light-emitting material layer away from the substrate; wherein, the electron transport layer, the electron injection layer, and the second electrode respectively cover all of the sub-pixel regions.

[0051] Optionally, in the above-mentioned display substrate provided by the embodiments of the present disclosure, in the first sub-pixel region and the second sub-pixel region, the target thickness of the hole injection layer is 15% - 17% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole injection layer is 12% - 15% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer;

[0052] In the first sub-pixel region, the target thickness of the hole transport layer is 6% - 8% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the hole transport layer is 7% - 10% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole transport layer is 9% - 11% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer;

[0053] In the first sub-pixel region, the target thickness of the light-emitting material layer is 38% - 40% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the light-emitting material layer is 30% - 32% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the light-emitting material layer is 25% - 28% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer.

[0054] Optionally, in the above display substrate provided by the embodiments of the present disclosure, in the first sub-pixel region, the target thickness of the hole injection layer is 10%-14% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the hole injection layer is 7%-13% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole injection layer is 8%-15% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer;

[0055] In the first sub-pixel region, the target thickness of the hole transport layer is 17%-22% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the hole transport layer is 18%-25% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole transport layer is 15%-22% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer;

[0056] In the first sub-pixel region, the target thickness of the light-emitting material layer is 63%-73% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the light-emitting material layer is 62%-75% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the light-emitting material layer is 63%-77% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer.

[0057] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the pixel defining layer includes a first pixel partition wall and a second pixel partition wall, the height of the first pixel partition wall is greater than the height of the second pixel partition wall, adjacent first pixel partition walls define a plurality of the sub-pixel regions, and adjacent second pixel partition walls define one of the sub-pixel regions;

[0058] The same light-emitting functional layer is disposed in the plurality of sub-pixel regions defined by the adjacent first pixel partition walls, and the height of the light-emitting functional layer is greater than the height of the second pixel partition wall;

[0059] The whole formed by a plurality of the sub-pixel regions defined by the adjacent first pixel partition walls is strip-shaped and distributed in a matrix;

[0060] The short side of the whole extends in the row direction, the light-emitting functional layer materials in all the wholes in the same column are the same, and are formed through a single inkjet printing process.

[0061] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the first pixel partition wall includes a first film layer and a second film layer located on the first film layer, and the second pixel partition wall includes the first film layer.

[0062] Optionally, in the above display substrate provided by the embodiments of the present disclosure, at least two of the sub-pixel regions of the same color are connected;

[0063] The sub-pixel regions in the same column have the same color, the sub-pixel regions of the same color in the same column are connected through a first channel, and the sub-pixel regions of the same color in different columns are connected through a second channel, and the sub-pixel regions of the same color in different columns are not adjacent to each other.

[0064] Optionally, in the above display substrate provided by the embodiments of the present disclosure, the first channel and the second channel are formed by removing part or all of the pixel defining layer between the two sub-pixel regions.

[0065] On the other hand, the embodiments of the present disclosure provide a display device, including the above display substrate. Description of the Drawings

[0066] Figure 1 is a flowchart of the manufacturing method of the display substrate provided by the embodiments of the present disclosure;

[0067] Figure 2 is a schematic structural diagram of the display substrate during the printing process provided by the embodiments of the present disclosure;

[0068] Figure 3 is a schematic diagram of a solution system provided by the embodiments of the present disclosure;

[0069] Figure 4 is another schematic diagram of the solution system provided by the embodiments of the present disclosure;

[0070] Figure 5 is another schematic diagram of the solution system provided by the embodiments of the present disclosure;

[0071] Figure 6 is a schematic structural diagram of the display substrate provided by the embodiments of the present disclosure;

[0072] Figure 7 is another schematic structural diagram of the display substrate provided by the embodiments of the present disclosure;

[0073] Figure 8 Another schematic structural diagram of the display substrate provided by the embodiment of the present disclosure;

[0074] Figure 9 Another schematic structural diagram of the display substrate provided by the embodiment of the present disclosure;

[0075] Figure 10 is Figure 9 The schematic cross-sectional structure diagram of A-A in;

[0076] Figure 11 is Figure 9 The schematic cross-sectional structure diagram of B-B in;

[0077] Figure 12 Another schematic structural diagram of the display substrate provided by the embodiment of the present disclosure;

[0078] Figure 13 Another schematic structural diagram of the display substrate provided by the embodiment of the present disclosure. Detailed implementation manners

[0079] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. It should be noted that the sizes and shapes of the various figures in the drawings do not reflect the actual proportions, and the purpose is only to schematically illustrate the content of the present disclosure. Also, the same or similar reference numerals throughout indicate the same or similar elements or elements having the same or similar functions. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0080] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second" and similar terms used in the specification and claims of the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "inside", "outside", "above", "below", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0081] Generally, before the inkjet printing process of OLED, it is necessary to pre-fabricate a pixel definition layer (PDL) to define the precise inflow of ink droplets into the designated RGB sub-pixel regions. The ink droplets need to fully spread within the RGB sub-pixels without overflowing.

[0082] In the related art, the inkjet printing process of OLED is being actively developed. Among them, the vacuum drying of the organic wet film is a key process that determines the film thickness uniformity. In particular, it is very necessary for the entire solvent atmosphere to be consistent after the ink droplets are printed for the film thickness uniformity. Usually, the solvent systems and ratios of the functional layers in different color sub-pixel regions are the same, and the saturated vapor pressures of the formed solutions are the same. However, due to the different aperture ratios and film thickness requirements of each RGB sub-pixel region, it is very difficult for the ink droplet volumes printed in the RGB sub-pixel regions to be the same. And due to the microcavity effect, the basic thicknesses of the current functional film layers are all R > G > B. Limited by the equipment, the concentration of the solution is limited, resulting in different solvent evaporation rates during the vacuum drying (VCD) process, and thus forming Mura. If we want to ensure that the ink droplet volumes in each sub-pixel region are the same, we need to change the concentration of each layer of ink droplets. However, different ink droplet concentrations result in different viscosities and drying rates, which are likely to cause the problem of printer nozzle clogging, with a large process difficulty coefficient and also likely to generate Mura. Therefore, in the related art, during the cooling and drying process of the ink droplets in the RGB sub-pixel regions, it is difficult to be compatible with the film thickness uniformity in the three RGB sub-pixel regions.

[0083] In order to at least solve the above technical problems existing in the related art, the embodiments of the present disclosure provide a method for manufacturing a display substrate, as Figure 1 shown, including the following steps:

[0084] S101. Provide a substrate, and the substrate includes a plurality of sub-pixel regions of different colors;

[0085] S102. Print the solution of the light-emitting functional layer in each sub-pixel region, wherein the volume of the solution in different color sub-pixel regions is positively correlated with the saturated vapor pressure of the solution;

[0086] S103. Perform vacuum drying on the solution to form a light-emitting functional layer with uniform film thickness.

[0087] In the above manufacturing method provided by the embodiments of the present disclosure, the volume of the solution in different color sub-pixel regions is positively correlated with the saturated vapor pressure of the solution, which can make the drying rates of the solutions with different volumes in different color sub-pixel regions basically the same, so that the time taken for the solvents in different color sub-pixel regions to completely volatilize is basically the same. That is to say, during the VCD process, the solvent atmospheres in different color sub-pixel regions are the same, and the film layer drying environments in different color sub-pixel regions are the same, thereby reducing the difficulty of the VCD process and being compatible with the film thickness uniformity of different color sub-pixel regions.

[0088] Optionally, in the above manufacturing method provided by the embodiments of the present disclosure, in order to facilitate the regulation of the saturated vapor pressure of the solution, the solution may include a mutually soluble first solvent and a second solvent, and the saturated vapor pressure of the first solvent is less than that of the second solvent. In some embodiments, the solution may only include a mutually soluble first solvent and a second solvent. At this time, the saturated vapor pressure of the solution is equal to the sum of the product of the saturated vapor pressure of the first solvent and the volume ratio of the first solvent in the solution, and the product of the saturated vapor pressure of the second solvent and the volume ratio of the second solvent in the solution.

[0089] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, as Figure 2 shown, the sub-pixel region may include: a plurality of red sub-pixel regions R, a plurality of green sub-pixel regions G, and a plurality of blue sub-pixel regions B;

[0090] Step S102 prints the solution of the light-emitting functional layer in a plurality of sub-pixel regions, and may be specifically implemented in the following manner:

[0091] Print the first solution of the light-emitting functional layer in a plurality of red sub-pixel regions R (as Figure 3 shown), print the second solution of the light-emitting functional layer in a plurality of green sub-pixel regions G (as Figure 4 shown), and print the third solution of the light-emitting functional layer in a plurality of blue sub-pixel regions B (as Figure 5 shown); wherein, the volume of the second solution is greater than or equal to the volume of the third solution and less than or equal to the volume of the first solution, and the saturated vapor pressure of the second solution is greater than or equal to the saturated vapor pressure of the third solution and less than or equal to the saturated vapor pressure of the first solution. The above conditions can make the film thickness of the light-emitting functional layer in the red sub-pixel region R, the green sub-pixel region G, and the blue sub-pixel region B decrease in turn, so as to meet the same film thickness trend of the light-emitting functional layer formed in the red sub-pixel region R, the green sub-pixel region G, and the blue sub-pixel region B as in the related art; and, the above conditions can also make the first solution, the second solution, and the third solution evaporate almost simultaneously, so as to take into account the film thickness uniformity of the light-emitting functional layer in the red sub-pixel region R, the green sub-pixel region G, and the blue sub-pixel region B, ensure the effective aperture ratio of the red sub-pixel region R, the green sub-pixel region G, and the blue sub-pixel region B, and improve the device life.

[0092] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, the ratio of the saturated vapor pressure of the first solution, the saturated vapor pressure of the second solution, and the saturated vapor pressure of the third solution may be (2.5 - 1):(2.5 - 1):1. Exemplarily, the volume fraction of the first solvent in the first solution, the second solution, and the third solution may increase in sequence, and the volume fraction of the second solvent in the first solution, the second solution, and the third solution may decrease in sequence to ensure that the saturated vapor pressures of the first solution, the second solution, and the third solution decrease in sequence. In this way, it can be ensured that during the simultaneous VCD cooling and drying process, the complete evaporation times of the first solution, the second solution, and the third solution are approximately the same, reducing the process difficulty of VCD and improving the film thickness uniformity.

[0093] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, to ensure that the saturated vapor pressures of the first solution, the second solution, and the third solution decrease in sequence, as Figures 3 to 5 shown, it can be achieved by the following method: in the first solution, the volume fraction of the first solvent a is 5% - 30%, and the volume fraction of the second solvent b is 70% - 95%; in the second solution, the volume fraction of the first solvent a is 30% - 60%, and the volume fraction of the second solvent b is 40% - 70%; in the third solution, the volume fraction of the first solvent a is 60% - 95%, and the volume fraction of the second solvent b is 5% - 40%.

[0094] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, the first solvent a may be one or any combination of cumene, cymene, 1,3,5 - trimethylbenzene, dimethylanisole, and p - diethylbenzene, and the second solvent b may be one or any combination of chlorobenzene, cyclohexanone, and o - xylene. Of course, in specific implementation, the first solvent a and the second solvent b may also be other solvents that are mutually soluble and have good solubility for the materials of the light - emitting functional layer and are well - known to those skilled in the art, and no specific limitation is made here.

[0095] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, to take into account the film thickness uniformity in each sub - pixel region, as Figure 2 shown, the light - emitting functional layer may be a hole injection layer HIL or a light - emitting material layer EML, and the volume of the second solution may be greater than the volume of the third solution and may be less than the volume of the first solution; in some other embodiments, the light - emitting functional layer may also be a hole transport layer HTL, and the volume of the second solution may be greater than or equal to the volume of the third solution and may be less than or equal to the volume of the first solution.

[0096] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, in order to match the light-emitting efficiency in each sub-pixel region, when the light-emitting functional layer is a hole injection layer HIL or a hole transport layer HTL, the concentrations of the first solution, the second solution, and the third solution can be the same; when the light-emitting functional layer is a light-emitting material layer EML, the concentration of the first solution can be greater than or equal to the concentration of the third solution and can be less than or equal to the concentration of the second solution.

[0097] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, after performing step S101 to provide a substrate, and before performing step S102 to print the solution of the light-emitting functional layer in each sub-pixel region, as Figure 6 shown, the following steps can also be performed:

[0098] Form a pixel definition layer PDL on the substrate PI. The pixel definition layer PDL has a first pixel opening K1 in the red sub-pixel region R, a second pixel opening K2 in the green sub-pixel region G, and a third pixel opening K3 in the blue sub-pixel region B; the area of the third pixel opening K3 can be smaller than the area of the second pixel opening K2 and can be larger than the area of the first pixel opening K1. The pixel definition layer PDL with different opening sizes can define the solution to flow precisely into the RGB sub-pixel regions.

[0099] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, the multiple green sub-pixel regions G include: multiple first-type green sub-pixel regions G1 and multiple second-type green sub-pixel regions G2; the area of the second pixel opening K2 corresponding to the first-type green sub-pixel region G1 is larger than the area of the second pixel opening K2 corresponding to the second-type green sub-pixel region G2; the saturated vapor pressure of the second solution corresponding to the first-type green sub-pixel region G1 is less than the saturated vapor pressure of the second solution corresponding to the second-type green sub-pixel region G2. This can enable the second solution in the first-type green sub-pixel region G1 and the second solution in the second-type green sub-pixel region G2 to evaporate almost simultaneously, thereby ensuring the film thickness uniformity between the first-type green sub-pixel region G1 and the second-type green sub-pixel region G2.

[0100] In some embodiments, in order to reduce the difference in film thickness uniformity among the sub-pixel regions, the ratio of the saturated vapor pressure of the first solution, the saturated vapor pressure of the second solution corresponding to the first-type green sub-pixel region, the saturated vapor pressure of the second solution corresponding to the second-type green sub-pixel region, and the saturated vapor pressure of the third solution can be 1.746:1.404:1.378:1.

[0101] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, after performing step S101 to provide a substrate, and before performing the above step to form the pixel definition layer PDL on the substrate PI, as Figure 6As shown, the following steps may also be performed:

[0102] Form a plurality of first electrodes Anode in a plurality of sub-pixel regions.

[0103] In some embodiments, in the above manufacturing method provided by the embodiments of the present disclosure, after performing step S103 to perform vacuum drying on the solution to form a light-emitting functional layer with a uniform film thickness, the following steps may also be performed:

[0104] Form an electron transport layer ETL, an electron injection layer EIL, and a second electrode Cathode in sequence on the light-emitting functional layer (specifically, it may be a light-emitting material layer EML).

[0105] Based on the same inventive concept, the embodiments of the present disclosure also provide a display substrate. Since the principle of solving problems by this display substrate is similar to that of the above manufacturing method, therefore, for the implementation of this display substrate provided by the embodiments of the present disclosure, reference may be made to the implementation of the above manufacturing method provided by the embodiments of the present disclosure, and the repeated parts will not be elaborated.

[0106] In some embodiments, as Figures 6 to 9 shown, the above display substrate provided by the embodiments of the present disclosure may include:

[0107] A substrate PI, which has a plurality of sub-pixel regions P with different light-emitting colors;

[0108] A pixel definition layer PDL, located above the substrate PI, and the pixel definition layer PDL has pixel openings K in each sub-pixel region;

[0109] A light-emitting functional layer EL, located on the side of the pixel definition layer PDL away from the substrate PI, and at least part of the light-emitting functional layer EL is located within the pixel opening K. The light-emitting functional layer EL may include a central region d far from the pixel definition layer PDL, a climbing region f in contact with the pixel definition layer PDL, and a transition region e located between the central region d and the climbing region f;

[0110] In the direction perpendicular to the substrate PI, the difference between the thickness h1 of the light-emitting functional layer EL in the central region d and the target thickness of the light-emitting functional layer EL may be less than or equal to 5 nm, the difference between the thickness h2 of the light-emitting functional layer EL in the transition region e and the target thickness of the light-emitting functional layer EL may be greater than 5 nm and less than or equal to 20 nm, and the difference between the thickness h3 of the light-emitting functional layer EL in the climbing region f and the target thickness of the light-emitting functional layer EL may be greater than 20 nm.

[0111] It should be noted that in the present disclosure, the target thickness of the light-emitting functional layer EL specifically refers to the designed thickness of the light-emitting functional layer EL, and the thicknesses h1 of the central region d, h2 of the transition region e, and h3 of the climbing region f all refer to the actual thicknesses of each region in the product.

[0112] Taking a 55-inch 4K bottom-emission display device as an example, the thickness of the first electrode Anode formed before manufacturing the pixel definition layer PDL of this bottom-emission display device is 70 nm.

[0113] Specifically, within the blue sub-pixel region B, the target thickness of the hole injection layer HIL is 30 nm, the thickness of the central region d is 30 nm - 35 nm, the thickness of the transition region e is 35 - 50 nm, and the thickness of the transition region c is greater than or equal to 50 nm; the target thickness of the hole transport layer HTL is 20 nm, the thickness of the central region d is 20 nm - 25 nm, the thickness of the transition region e is 25 nm - 40 nm, and the thickness of the climbing region f is greater than 40 nm; the target thickness of the blue light-emitting material layer B-EML is 60 nm, the thickness of the central region d is 60 nm - 65 nm, the thickness of the transition region e is 65 nm - 80 nm, and the thickness of the climbing region f is greater than 80 nm.

[0114] Within the green sub-pixel region G, the target thickness of the hole injection layer HIL is 40 nm, the thickness of the central region d is 40 nm - 45 nm, the thickness of the transition region e is 45 - 60 nm, and the thickness of the transition region c is greater than or equal to 60 nm; the target thickness of the hole transport layer HTL is 20 nm, the thickness of the central region d is 20 nm - 25 nm, the thickness of the transition region e is 25 nm - 40 nm, and the thickness of the climbing region f is greater than or equal to 40 nm; the target thickness of the green light-emitting material layer G-EML is 80 nm, the thickness of the central region d is 80 nm - 85 nm, the thickness of the transition region e is 85 nm - 100 nm, and the thickness of the climbing region f is greater than or equal to 100 nm.

[0115] Within the red sub-pixel region R, the target thickness of the hole injection layer HIL is 40 nm, the thickness of the central region d is 40 nm - 45 nm, the thickness of the transition region e is 45 - 60 nm, and the thickness of the transition region c is greater than or equal to 60 nm; the target thickness of the hole transport layer HTL is 20 nm, the thickness of the central region d is 20 nm - 25 nm, the thickness of the transition region e is 25 nm - 40 nm, and the thickness of the climbing region f is greater than or equal to 40 nm; the target thickness of the red light-emitting material layer R-EML is 120 nm, the thickness of the central region d is 120 nm - 125 nm, the thickness of the transition region e is 125 nm - 140 nm, and the thickness of the climbing region f is greater than or equal to 140 nm.

[0116] Taking a 55-inch 8K bottom-emission display device as an example, the thickness of the first electrode Anode formed before manufacturing the pixel definition layer PDL of this bottom-emission display device is 15 nm.

[0117] Specifically, within the blue sub-pixel region B, the target thickness of the hole injection layer HIL is 6 nm, the thickness of the central region d is 6 nm - 11 nm, the thickness of the transition region e is 11 - 26 nm, and the thickness of the transition region c is greater than or equal to 26 nm; the target thickness of the hole transport layer HTL is 11 nm, the thickness of the central region d is 11 nm - 16 nm, the thickness of the transition region e is 16 nm - 31 nm, and the thickness of the climbing region f is greater than 31 nm; the target thickness of the blue light-emitting material layer B-EML is 55 nm, the thickness of the central region d is 55 nm - 60 nm, the thickness of the transition region e is 60 nm - 75 nm, and the thickness of the climbing region f is greater than 75 nm.

[0118] Within the green sub-pixel region G, the target thickness of the hole injection layer HIL is 6 nm, the thickness of the central region d is 6 nm - 11 nm, the thickness of the transition region e is 11 - 26 nm, and the thickness of the transition region c is greater than or equal to 26 nm; the target thickness of the hole transport layer HTL is 16 nm, the thickness of the central region d is 16 nm - 21 nm, the thickness of the transition region e is 21 nm - 36 nm, and the thickness of the climbing region f is greater than or equal to 36 nm; the target thickness of the green light-emitting material layer G-EML is 63 nm, the thickness of the central region d is 63 nm - 68 nm, the thickness of the transition region e is 68 nm - 83 nm, and the thickness of the climbing region f is greater than or equal to 83 nm.

[0119] Within the red sub-pixel region R, the target thickness of the hole injection layer HIL is 12 nm, the thickness of the central region d is 12 nm - 17 nm, the thickness of the transition region e is 17 - 32 nm, and the thickness of the transition region c is greater than or equal to 32 nm; the target thickness of the hole transport layer HTL is 21 nm, the thickness of the central region d is 21 nm - 26 nm, the thickness of the transition region e is 26 nm - 41 nm, and the thickness of the climbing region f is greater than or equal to 41 nm; the target thickness of the red light-emitting material layer R-EML is 87 nm, the thickness of the central region d is 87 nm - 92 nm, the thickness of the transition region e is 92 nm - 107 nm, and the thickness of the climbing region f is greater than or equal to 107 nm.

[0120] In some embodiments, in the above-mentioned display substrate provided by the embodiments of the present disclosure, 70%-90% of the entire projected area radiating outward from the center of the light-emitting functional layer EL and having a shape contour substantially the same as that of the pixel opening K can be the central region a, and 0%-5% of the entire projected area covering the pixel defining layer PDL and having a shape contour substantially the same as that of the pixel opening K can be the climbing region f. The 5%-30% of the entire projected area between the climbing region f and the central region a and having a shape contour substantially the same as that of the pixel opening K can be the transition region e. In other words, the area ratio of the central region d to the light-emitting functional layer EL can reach 70%-90%, the climbing region f only accounts for 0%-5% of the area of the light-emitting functional layer EL, and the area ratio of the transition region e between the central region d and the climbing region f to the light-emitting functional layer EL is 5%-30%.

[0121] In some embodiments, in the above-mentioned display substrate provided by the embodiments of the present disclosure, the thickness uniformity of the light-emitting functional layer EL within the pixel opening K can have a positive correlation with the area of the pixel opening K. In other words, the larger the area of the pixel opening K, the better the thickness uniformity of the light-emitting functional layer EL.

[0122] In some embodiments, in the above-mentioned display substrate provided by the embodiments of the present disclosure, as Figure 6 shown, the sub-pixel region can include a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region. The pixel opening K includes a first pixel opening K1 located in the first sub-pixel region, a second pixel opening K2 located in the second sub-pixel region, and a third pixel opening K3 located in the third sub-pixel region. The area of the third pixel opening K3 can be greater than the area of the first pixel opening K1 and less than the area of the second pixel opening K2;

[0123] The light-emitting functional layer EL can include a hole injection layer HIL, a hole transport layer HTL, and a light-emitting material layer EML; the thickness uniformity of the hole injection layer HIL within the first pixel opening K1, the third pixel opening K3, and the second pixel opening K2 increases in sequence, the thickness uniformity of the hole transport layer HTL within the first pixel opening K1, the third pixel opening K3, and the second pixel opening K2 increases in sequence, and the thickness uniformity of the light-emitting material layer EML within the first pixel opening K1, the third pixel opening K3, and the second pixel opening K2 increases in sequence.

[0124] In some embodiments, the first sub-pixel region, the second sub-pixel region, and the third sub-pixel region may be a red sub-pixel region R, a green sub-pixel region G, and a blue sub-pixel region B in sequence. Taking a 55-inch 4K bottom-emission product as an example, the aperture ratio of the green sub-pixel region G (equivalent to the ratio of the area of the pixel aperture to the area of the sub-pixel region) > the aperture ratio of the blue sub-pixel region B > the aperture ratio of the red sub-pixel region R. In some embodiments, the aperture ratio of the green sub-pixel region G is 23.6%, the aperture ratio of the blue pixel region B is 20.5%, and the aperture ratio of the red sub-pixel region R is 19.8%. Under the above conditions, the morphological trends of the hole injection layer HIL, the hole transport layer HTL, and the light-emitting material layer EML are basically the same, where the morphology of the hole injection layer HIL determines the morphologies of the hole transport layer HTL and the light-emitting material layer EML. Taking the morphology of HIL as an example, the climbing trends (i.e., the U-shaped upward trend) in the long side g and the short side h of the pixel aperture K (as Figure 8 shown) are green sub-pixel region G > blue sub-pixel region B > red sub-pixel region R. In some embodiments, the film thickness uniformities of HIL, HTL, and EML in the green sub-pixel region G are 76.2%, 80%, and 86.2% in sequence, the film thickness uniformities of HIL, HTL, and EML in the blue sub-pixel region B are 74.2%, 78.6, and 82.2% in sequence, and the film thickness uniformities of HIL, HTL, and EML in the red sub-pixel region R are 71.6%, 74.1%, and 80.5% in sequence.

[0125] It should be noted that in the present disclosure, the film thickness uniformity is equal to the percentage of the area of the central region d of the film layer in the area of the light-emitting functional layer EL.

[0126] In some embodiments, the display substrate provided in the present disclosure can be applied to a bottom-emission display device of 55ich 4K, where the thickness of the first electrode Anode is 70nm, the average thickness of the hole injection layer HIL in the first sub-pixel region is 40nm - 50nm, the average thickness in the second sub-pixel region is 40nm - 50nm, and the average thickness in the third sub-pixel region is 30nm - 40nm; the average thickness of the hole transport layer HTL in the first sub-pixel region is 20nm - 28nm, the average thickness in the second sub-pixel region is 20nm - 27nm, and the average thickness in the third sub-pixel region is 20nm - 27nm; the average thickness of the light-emitting material layer EML in the first sub-pixel region is 120nm - 135nm, the average thickness in the second sub-pixel region is 80nm - 95nm, and the average thickness in the third sub-pixel region is 60nm - 72nm; the luminous efficiency of the first sub-pixel region is 11.5Cd / A - 15.6Cd / A, the luminous efficiency of the second sub-pixel region is 35.1Cd / A - 41.2Cd / A, and the luminous efficiency of the third sub-pixel region is 33Cd / A - 46Cd / A.

[0127] It should be noted that in the present disclosure, the average thickness of the film layer is equal to the weighted average of the central region d, the transition region e, and the climbing region f in the sub-pixel region.

[0128] In some embodiments, the display substrate can be applied to a 55-inch 8K bottom-emission display device. The thickness of the first electrode Anode is 15 nm. The average thickness of the hole injection layer HIL in the first sub-pixel region can be 12 nm - 20 nm, in the second sub-pixel region can be 6 nm - 12 nm, and in the third sub-pixel region can be 6 nm - 12 nm; the average thickness of the hole transport layer in the first sub-pixel region is 21 nm - 30 nm, in the second sub-pixel region is 16 nm - 26 nm, and in the third sub-pixel region is 11 nm - 20 nm; the average thickness of the light-emitting material layer in the first sub-pixel region is 87 nm - 105 nm, in the second sub-pixel region is 63 nm - 78 nm, and in the third sub-pixel region is 55 nm - 70 nm; the luminous efficiency of the first sub-pixel region is 16.8 Cd / A - 20.3 Cd / A, the luminous efficiency of the second sub-pixel region is 36.5 Cd / A - 49.5 Cd / A, and the luminous efficiency of the third sub-pixel region is 32.4 Cd / A - 47.2 Cd / A.

[0129] In some embodiments, in the above display substrate provided by the embodiments of the present disclosure, as Figure 6 shown, it may further include: an electron transport layer ETL, an electron injection layer EIL, and a second electrode Cathode sequentially disposed on the side of the light-emitting material layer EML away from the substrate PI; wherein, the electron transport layer ETL, the electron injection layer EIL, and the second electrode Cathode respectively cover all sub-pixel regions, that is, the electron transport layer ETL, the electron injection layer EIL, and the second electrode Cathode are all disposed over the entire surface.

[0130] In some embodiments, in the above display substrate provided by the embodiments of the present disclosure, in order to match the luminous efficiency of each sub-pixel region, when applied to a 55-inch 4K bottom-emission display device, the thickness of the first electrode Anode can be set to 70 nm. In the first sub-pixel region and the second sub-pixel region, the target thickness of the hole injection layer HIL can be 15% - 17% of the sum of the thicknesses of the hole injection layer HIL, the hole transport layer HTL, the light-emitting material layer EML, the electron transport layer ETL, and the electron injection layer EIL; in the third sub-pixel region, the target thickness of the hole injection layer HIL can be 12% - 15% of the sum of the thicknesses of the hole injection layer HIL, the hole transport layer HTL, the light-emitting material layer EML, the electron transport layer ETL, and the electron injection layer EIL;

[0131] In the first sub-pixel region, the target thickness of the hole transport layer (HTL) can be 6%-8% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the second sub-pixel region, the target thickness of the hole transport layer (HTL) can be 7%-10% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the third sub-pixel region, the target thickness of the hole transport layer (HTL) can be 9%-11% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL).

[0132] In the first sub-pixel region, the target thickness of the light-emitting material layer (EML) can be 38%-40% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the second sub-pixel region, the target thickness of the light-emitting material layer (EML) can be 30%-32% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the third sub-pixel region, the target thickness of the light-emitting material layer (EML) can be 25%-28% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL).

[0133] In some embodiments, in the above display substrate provided by the embodiments of the present disclosure, in order to match the light-emitting efficiency of each sub-pixel region, when the display substrate is applied to a top-emitting display device of 55ich 8K, the thickness of the first electrode (Anode) can be set to 15 nm. In the first sub-pixel region, the target thickness of the hole injection layer (HIL) can be 10%-14% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the second sub-pixel region, the target thickness of the hole injection layer (HIL) can be 7%-13% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the third sub-pixel region, the target thickness of the hole injection layer (HIL) can be 8%-15% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL).

[0134] In the first sub-pixel region, the target thickness of the hole transport layer (HTL) can be 17% - 22% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the second sub-pixel region, the target thickness of the hole transport layer (HTL) can be 18% - 25% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the third sub-pixel region, the target thickness of the hole transport layer (HTL) can be 15% - 22% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL).

[0135] In the first sub-pixel region, the target thickness of the light-emitting material layer (EML) can be 63% - 73% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the second sub-pixel region, the target thickness of the light-emitting material layer (EML) can be 62% - 75% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL); in the third sub-pixel region, the target thickness of the light-emitting material layer (EML) can be 63% - 77% of the sum of the thicknesses of the hole injection layer (HIL), the hole transport layer (HTL), the light-emitting material layer (EML), the electron transport layer (ETL), and the electron injection layer (EIL).

[0136] In some embodiments, the first sub-pixel region of the present disclosure can be a red sub-pixel region (R), the second sub-pixel region can be a green sub-pixel region (G), and the third sub-pixel region can be a blue sub-pixel region (B).

[0137] In some embodiments, in the above-mentioned display substrate provided by the embodiments of the present disclosure, as Figure 9 and Figure 10 shown, the pixel defining layer (PDL) can include a first pixel partition wall (PDL1) and a second pixel partition wall (PDL2). The height of the first pixel partition wall (PDL1) can be greater than the height of the second pixel partition wall (PDL2). Adjacent first pixel partition walls (PDL1) define multiple sub-pixel regions (P), and adjacent second pixel partition walls (PDL2) define one sub-pixel region (P);

[0138] The same light-emitting functional layer (EL) is disposed in the multiple sub-pixel regions (P) defined by adjacent first pixel partition walls (PDL1), and the height of the light-emitting functional layer (EL) is greater than the height of the second pixel partition wall (PDL2);

[0139] The overall (P') formed by the multiple sub-pixel regions (P) defined by adjacent first pixel partition walls (PDL1) is strip-shaped and arranged in a matrix;

[0140] The short side of the overall P' extends in the row direction. The EL materials of the light-emitting functional layers within all the overall P's in the same column are the same and are formed through a single inkjet printing process.

[0141] For the display substrate with the above structure, the thickness uniformity of the display film layers within the sub-pixel area can be ensured to be relatively good.

[0142] In some embodiments, in the above display substrate provided by the embodiments of the present disclosure, as Figure 11 shown, the first pixel partition wall PDL1 may include a first film layer n and a second film layer m located on the first film layer n. The second pixel partition wall PDL2 may include the first film layer n. With such a setting, the height difference between the first pixel partition wall PDL1 and the second pixel partition wall PDL2 can be the thickness of the second film layer m.

[0143] In some embodiments, in the above display substrate provided by the embodiments of the present disclosure, as Figure 12 and Figure 13 shown, at least two sub-pixel areas P of the same color can be connected;

[0144] The sub-pixel areas P in the same column have the same color. The sub-pixel areas P of the same color in the same column are connected through the first channel T1, and the sub-pixel areas P of the same color in different columns are connected through the second channel T2. The sub-pixel areas P of the same color in different columns are not adjacent to each other.

[0145] By setting at least two sub-pixel areas P to be connected, the fluidity of the solution is increased. Therefore, it is easier to form a film layer with uniform thickness within the sub-pixel area P.

[0146] In some embodiments, in the above display substrate provided by the embodiments of the present disclosure, as Figure 12 and Figure 13 shown, the first channel T1 and the second channel T2 are formed by removing part or all of the pixel defining layer PDL between two sub-pixel areas P. That is, the widths of the first channel T1 and the second channel T2 can be less than or equal to the width of the sub-pixel area P.

[0147] Based on the same inventive concept, the embodiments of the present disclosure also provide a display device, including the above display substrate provided by the embodiments of the present disclosure. Since the principle of solving problems of this display device is similar to that of the above display substrate, therefore, for the implementation of this display device provided by the embodiments of the present disclosure, reference can be made to the implementation of the above display substrate provided by the embodiments of the present disclosure, and the repeated parts will not be elaborated again.

[0148] In some embodiments, the display device may be: any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, a smart watch, a fitness bracelet, a personal digital assistant, etc. The display device includes, but is not limited to: components such as a radio frequency unit, a network module, an audio output unit, an input unit, a sensor, a display unit, a user input unit, an interface unit, a memory, a processor, and a power supply. Those skilled in the art can understand that the structure of the above display device does not constitute a limitation on the display device. The display device may include more or fewer of the above components, or combine certain components, or have different component arrangements. In addition, the above display device provided by the embodiments of the present disclosure can be applied to display technologies with drive circuits, such as organic electroluminescence display (OLED) and quantum dot display (QLED), and is not limited herein.

[0149] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Thus, if these modifications and variations of the embodiments of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure also intends to include these changes and modifications.

Claims

1. A manufacturing method of a display substrate, wherein, Comprising: Providing a substrate, the substrate including a plurality of sub-pixel regions of different colors; Printing a solution of a light-emitting functional layer in each of the sub-pixel regions, wherein the volume of the solution in the sub-pixel regions of different colors is positively correlated with the saturated vapor pressure of the solution; the sub-pixel regions include: a plurality of red sub-pixel regions, a plurality of green sub-pixel regions, and a plurality of blue sub-pixel regions; Printing the solution of the light-emitting functional layer in the plurality of sub-pixel regions specifically includes: Printing a first solution of the light-emitting functional layer in the plurality of red sub-pixel regions, printing a second solution of the light-emitting functional layer in the plurality of green sub-pixel regions, and printing a third solution of the light-emitting functional layer in the plurality of blue sub-pixel regions; wherein, the volume of the second solution is greater than or equal to the volume of the third solution and less than or equal to the volume of the first solution, and the saturated vapor pressure of the second solution is greater than or equal to the saturated vapor pressure of the third solution and less than or equal to the saturated vapor pressure of the first solution; Performing vacuum drying on the solution to form the light-emitting functional layer with uniform film thickness; wherein, the solution includes a mutually soluble first solvent and a second solvent, the saturated vapor pressure of the first solvent is less than the saturated vapor pressure of the second solvent, the volume ratio of the first solvent in the first solution, the second solution, and the third solution increases in sequence, and the volume ratio of the second solvent in the first solution, the second solution, and the third solution decreases in sequence.

2. The manufacturing method according to claim 1, wherein, The ratio of the saturated vapor pressure of the first solution, the saturated vapor pressure of the second solution, and the saturated vapor pressure of the third solution is (2.5 - 1):(2.5 - 1):

1.

3. The manufacturing method according to claim 1, wherein, In the first solution, the volume ratio of the first solvent is 5% - 30%, and the volume ratio of the second solvent is 70% - 95%; In the second solution, the volume ratio of the first solvent is 30% - 60%, and the volume ratio of the second solvent is 40% - 70%; In the third solution, the volume ratio of the first solvent is 60% - 95%, and the volume ratio of the second solvent is 5% - 40%.

4. The manufacturing method according to claim 3, wherein, The first solvent is one or any combination of cumene, cymene, 1,3,5-trimethylbenzene, dimethylanisole, and p-diethylbenzene, and the second solvent is one or any combination of chlorobenzene, cyclohexanone, and o-xylene.

5. The manufacturing method according to claim 1, wherein, The light-emitting functional layer is a hole injection layer or a light-emitting material layer, and the volume of the second solution is greater than the volume of the third solution and less than the volume of the first solution; The light-emitting functional layer is a hole transport layer, and the volume of the second solution is greater than or equal to the volume of the third solution and less than or equal to the volume of the first solution.

6. The manufacturing method according to claim 5, wherein, The light-emitting functional layer is the hole injection layer or the hole transport layer, and the concentrations of the first solution, the second solution, and the third solution are the same; The light-emitting functional layer is the light-emitting material layer, and the concentration of the first solution is greater than or equal to the concentration of the third solution and less than or equal to the concentration of the second solution.

7. The manufacturing method according to claim 1 or 4, wherein, After providing a substrate, and before simultaneously printing the solution of the light-emitting functional layer in the plurality of sub-pixel regions, it further includes: Forming a pixel defining layer on the substrate, the pixel defining layer having a first pixel opening in the red sub-pixel region, a second pixel opening in the green sub-pixel region, and a third pixel opening in the blue sub-pixel region; The area of the third pixel opening is smaller than the area of the second pixel opening and larger than the area of the first pixel opening.

8. The manufacturing method according to claim 7, wherein The plurality of green sub-pixel regions include: a plurality of first-type green sub-pixel regions and a plurality of second-type green sub-pixel regions; The area of the second pixel opening corresponding to the first-type green sub-pixel region is larger than the area of the second pixel opening corresponding to the second-type green sub-pixel region; The saturated vapor pressure of the second solution corresponding to the first-type green sub-pixel region is smaller than the saturated vapor pressure of the second solution corresponding to the second-type green sub-pixel region.

9. The manufacturing method according to claim 8, wherein, The ratio of the saturated vapor pressure of the first solution, the saturated vapor pressure of the second solution corresponding to the first-type green sub-pixel region, the saturated vapor pressure of the second solution corresponding to the second-type green sub-pixel region, and the saturated vapor pressure of the third solution is 1.746:1.404:1.378:

1.

10. The manufacturing method according to claim 7, wherein After providing a substrate, and before forming a pixel defining layer on the substrate, it further includes: Forming a plurality of first electrodes in the plurality of sub-pixel regions.

11. The manufacturing method according to claim 1, wherein, After vacuum drying the solution to form the light-emitting functional layer with a uniform film thickness, it further includes: Sequentially forming an electron transport layer, an electron injection layer, and a second electrode on the light-emitting functional layer.

12. A display substrate, wherein, It includes: A substrate having a plurality of sub-pixel regions with different light-emitting colors; The substrate is fabricated by the following method: printing the solution of the light-emitting functional layer in each of the sub-pixel regions, wherein the volume of the solution in the sub-pixel regions of different colors is positively correlated with the saturated vapor pressure of the solution; the sub-pixel regions include: a plurality of red sub-pixel regions, a plurality of green sub-pixel regions, and a plurality of blue sub-pixel regions; Printing the solution of the light-emitting functional layer in the plurality of sub-pixel regions specifically includes: Printing the first solution of the light-emitting functional layer in the plurality of red sub-pixel regions, printing the second solution of the light-emitting functional layer in the plurality of green sub-pixel regions, and printing the third solution of the light-emitting functional layer in the plurality of blue sub-pixel regions; wherein, the volume of the second solution is greater than or equal to the volume of the third solution and less than or equal to the volume of the first solution, and the saturated vapor pressure of the second solution is greater than or equal to the saturated vapor pressure of the third solution and less than or equal to the saturated vapor pressure of the first solution; A pixel defining layer located above the substrate, the pixel defining layer having pixel openings in each of the sub-pixel regions; A light-emitting functional layer located on the side of the pixel defining layer away from the substrate, at least a part of the light-emitting functional layer is located within the pixel openings, and the light-emitting functional layer includes a central region away from the pixel defining layer, a climbing region in contact with the pixel defining layer, and a transition region located between the central region and the climbing region; The light-emitting functional layer is fabricated by the following method: the solution is vacuum-dried to form the light-emitting functional layer with a uniform film thickness; wherein, the solution includes a mutually soluble first solvent and a second solvent, the saturation vapor pressure of the first solvent is less than that of the second solvent, the volume proportion of the first solvent in the first solution, the second solution, and the third solution increases in sequence, and the volume proportion of the second solvent in the first solution, the second solution, and the third solution decreases in sequence; In the direction perpendicular to the substrate, the difference between the thickness of the light-emitting functional layer in the central region and the target thickness of the light-emitting functional layer is less than or equal to 5 nm, the difference between the thickness of the light-emitting functional layer in the transition region and the target thickness of the light-emitting functional layer is greater than 5 nm and less than or equal to 20 nm, and the difference between the thickness of the light-emitting functional layer in the climbing region and the target thickness of the light-emitting functional layer is greater than 20 nm.

13. The display substrate according to claim 12, wherein, 70%-90% of the entire projected area that radiates outward from the center of the light-emitting functional layer and is roughly the same as the contour of the pixel opening shape is the central region, 0%-5% of the entire projected area that covers the pixel defining layer and is roughly the same as the contour of the pixel opening shape is the climbing region, and 5%-30% of the entire projected area that is between the climbing region and the central region and is roughly the same as the contour of the pixel opening shape is the transition region.

14. The display substrate according to claim 12, wherein, The thickness uniformity of the light-emitting functional layer within the pixel opening is positively correlated with the area of the pixel opening.

15. The display substrate according to claim 14, wherein, The sub-pixel region includes a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region. The pixel opening includes a first pixel opening located in the first sub-pixel region, a second pixel opening located in the second sub-pixel region, and a third pixel opening located in the third sub-pixel region. The area of the third pixel opening is greater than the area of the first pixel opening and less than the area of the second pixel opening; The light-emitting functional layer includes a hole injection layer, a hole transport layer, and a light-emitting material layer; the thickness uniformity of the hole injection layer within the first pixel opening, the third pixel opening, and the second pixel opening increases in sequence, the thickness uniformity of the hole transport layer within the first pixel opening, the third pixel opening, and the second pixel opening increases in sequence, and the thickness uniformity of the light-emitting material layer within the first pixel opening, the third pixel opening, and the second pixel opening increases in sequence.

16. The display substrate according to claim 12, wherein, The sub-pixel region includes a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region. The light-emitting functional layer includes a hole injection layer, a hole transport layer, and a light-emitting material layer; The average thickness of the hole injection layer in the first sub-pixel region is 40 nm - 50 nm, the average thickness of the hole injection layer in the second sub-pixel region is 40 nm - 50 nm, and the average thickness of the hole injection layer in the third sub-pixel region is 30 nm - 40 nm; The average thickness of the hole transport layer in the first sub-pixel region is 20 nm - 28 nm, the average thickness of the hole transport layer in the second sub-pixel region is 20 nm - 27 nm, and the average thickness of the hole transport layer in the third sub-pixel region is 20 nm - 27 nm; The average thickness of the light-emitting material layer in the first sub-pixel region is 120nm-135nm, the average thickness in the second sub-pixel region is 80nm-95nm, and the average thickness in the third sub-pixel region is 60nm-72nm.

17. The display substrate according to claim 16, wherein, The luminous efficiency of the first sub-pixel area is 11.5Cd / A-15.6Cd / A, the luminous efficiency of the second sub-pixel area is 35.1Cd / A-41.2Cd / A, and the luminous efficiency of the third sub-pixel area is 33Cd / A-46Cd / A.

18. The display substrate according to claim 12, wherein, The sub-pixel region includes a first sub-pixel region, a second sub-pixel region and a third sub-pixel region, and the light-emitting functional layer includes a hole injection layer, a hole transport layer and a light-emitting material layer; The average thickness of the hole injection layer in the first sub-pixel region is 12nm-20nm, the average thickness in the second sub-pixel region is 6nm-12nm, and the average thickness in the third sub-pixel region is 6nm-12nm; The average thickness of the hole transport layer in the first sub-pixel region is 21nm-30nm, the average thickness in the second sub-pixel region is 16nm-26nm, and the average thickness in the third sub-pixel region is 11nm-20nm; The average thickness of the light-emitting material layer in the first sub-pixel region is 87nm-105nm, the average thickness in the second sub-pixel region is 63nm-78nm, and the average thickness in the third sub-pixel region is 55nm-70nm.

19. The display substrate according to claim 18, wherein, The luminous efficiency of the first sub-pixel area is 16.8Cd / A-20.3Cd / A, the luminous efficiency of the second sub-pixel area is 36.5Cd / A-49.5Cd / A, and the luminous efficiency of the third sub-pixel area is 32.4Cd / A-47.2Cd / A.

20. The display substrate according to any one of claims 15-19, wherein, Also includes: An electron transport layer, an electron injection layer and a second electrode are sequentially arranged on a side of the light-emitting material layer away from the base substrate; wherein the electron transport layer, the electron injection layer and the second electrode respectively cover the entire sub-pixel area.

21. The display substrate according to claim 20, wherein, In the first sub-pixel region and the second sub-pixel region, the target thickness of the hole injection layer is 15%-17% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer and the electron injection layer; in the third sub-pixel region, the target thickness of the hole injection layer is 12%-15% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer and the electron injection layer; In the first sub-pixel region, the target thickness of the hole transport layer is 6%-8% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the hole transport layer is 7%-10% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole transport layer is 9%-11% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; In the first sub-pixel region, the target thickness of the light-emitting material layer is 38%-40% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the light-emitting material layer is 30%-32% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the light-emitting material layer is 25%-28% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer.

22. The display substrate according to claim 20, wherein In the first sub-pixel region, the target thickness of the hole injection layer is 10%-14% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the hole injection layer is 7%-13% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole injection layer is 8%-15% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; In the first sub-pixel region, the target thickness of the hole transport layer is 17%-22% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the hole transport layer is 18%-25% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the hole transport layer is 15%-22% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; In the first sub-pixel region, the target thickness of the light-emitting material layer is 63%-73% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the second sub-pixel region, the target thickness of the light-emitting material layer is 62%-75% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer; in the third sub-pixel region, the target thickness of the light-emitting material layer is 63%-77% of the sum of the thicknesses of the hole injection layer, the hole transport layer, the light-emitting material layer, the electron transport layer, and the electron injection layer.

23. The display substrate according to claim 12, wherein, The pixel defining layer includes a first pixel partition wall and a second pixel partition wall. The height of the first pixel partition wall is greater than the height of the second pixel partition wall. Adjacent first pixel partition walls define a plurality of the sub-pixel regions, and adjacent second pixel partition walls define one of the sub-pixel regions; The same light-emitting functional layer is provided in the plurality of sub-pixel regions defined by adjacent first pixel partition walls, and the height of the light-emitting functional layer is greater than the height of the second pixel partition wall; The plurality of sub-pixel regions defined by adjacent first pixel partition walls form an integral body that is elongated and arranged in a matrix; The short side of the integral body extends in the row direction. The light-emitting functional layer materials in all of the integral bodies in the same column are the same and are formed through a single inkjet printing process.

24. The display substrate according to claim 23, wherein, The first pixel partition wall includes a first film layer and a second film layer located on the first film layer. The second pixel partition wall includes the first film layer.

25. The display substrate according to claim 12, wherein, At least two of the sub-pixel regions of the same color are connected; The colors of the sub-pixel regions in the same column are the same. The sub-pixel regions of the same color in the same column are connected through a first channel, and the sub-pixel regions of the same color in different columns are connected through a second channel. The sub-pixel regions of the same color in different columns are not adjacent to each other.

26. The display substrate according to claim 25, wherein, The first channel and the second channel are formed by removing part or all of the pixel defining layer between two of the sub-pixel regions.

27. A display device, wherein, Including the display substrate according to any one of claims 12-26.

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