Display substrate and display device

Abstract

The invention provides a display substrate and a display device. The display substrate comprises a substrate body; the first electrode is positioned on the substrate; the first light-emitting layer is positioned on one side, far away from the substrate, of the first electrode; the first hole blocking layer is positioned on one side, far away from the substrate, of the first light-emitting layer; the first electron transport layer is positioned on one side, far away from the substrate, of the first hole barrier layer; the electron injection layer is positioned on one side, far away from the substrate, of the first electron transmission layer; the second electrode is positioned on one side, far away from the substrate, of the electron injection layer; the optical extraction layer is positioned on one side, far away from the substrate, of the second electrode; the protection layer is positioned on one side, far away from the substrate, of the optical extraction layer; the packaging layer is located on the side, away from the substrate, of the protection layer, the refractive index of the material of the optical extraction layer is larger than that of the material of the protection layer, and the refractive index of the material of the protection layer is larger than that of the material of the second electrode.

Description

Display substrate and display device Technical Field

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

[0002] Organic Light-Emitting Diode (OLED) devices have attracted considerable attention due to their self-luminescence, rich colors, fast response time, wide viewing angle, light weight, thinness, low power consumption, and flexible display capabilities. However, in related technologies, the greater the fluctuation in the thickness of each film layer in an OLED, the greater the impact on screen display uniformity, leading to color shift issues in OLEDs.

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

[0004] Summary of the Invention

[0005] In order to solve at least one aspect of the above problems, embodiments of the present disclosure provide a display substrate and a display device including the display substrate.

[0006] In one aspect, a display substrate is provided, comprising: a base substrate; a first electrode located on the base substrate; a first light-emitting layer located on a side of the first electrode away from the base substrate; a first hole blocking layer located on a side of the first light-emitting layer away from the base substrate; a first electron transport layer located on a side of the first hole blocking layer away from the base substrate; an electron injection layer located on a side of the first electron transport layer away from the base substrate; a second electrode located on a side of the electron injection layer away from the base substrate; an optical extraction layer located on a side of the second electrode away from the base substrate; a protective layer located on a side of the optical extraction layer away from the base substrate; and an encapsulation layer located on a side of the protective layer away from the base substrate, wherein the refractive index of the material of the optical extraction layer is greater than the refractive index of the material of the protective layer, and the refractive index of the material of the protective layer is greater than the refractive index of the material of the second electrode.

[0007] According to some exemplary embodiments, the display substrate includes a color deviation adjustment layer, the color deviation adjustment layer is selected from at least one of the optical extraction layer, the protective layer, and the encapsulation layer, and the color deviation adjustment layer and the second electrode satisfy the following relationship: ∑(n i L i ) / ∑L i =K,

[0008] Wherein, n represents the refractive index of the material of each layer, L represents the thickness of each layer, i is a positive integer, and K is greater than 1.

[0009] According to some exemplary embodiments, the encapsulation layer includes: a first inorganic layer located on a side of the protective layer away from the base substrate; a second intercalation layer located on a side of the first inorganic layer away from the base substrate; an organic layer located on a side of the second intercalation layer away from the base substrate; and a second inorganic layer located on a side of the organic layer away from the base substrate.

[0010] According to some exemplary embodiments, the refractive index n1 of the material of the second electrode, the thickness L1 of the second electrode, the refractive index n2 of the material of the second intercalation layer, and the thickness L2 of the second intercalation layer satisfy the following relationship: (n1L1+n2L2) / (L1+L2)=K,

[0011] Among them, the range of K is 1.3 to 1.6.

[0012] According to some exemplary embodiments, a refractive index n1 of a material of the second electrode and a refractive index n2 of a material of the second intercalation layer satisfy |n1-n2|>1.

[0013] According to some exemplary embodiments, the encapsulation layer includes: a first intercalation layer located on a side of the protective layer away from the base substrate; a first inorganic layer located on a side of the first intercalation layer away from the base substrate; an organic layer located on a side of the first inorganic layer away from the base substrate; and a second inorganic layer located on a side of the organic layer away from the base substrate.

[0014] According to some exemplary embodiments, the refractive index n1 of the material of the second electrode, the thickness L1 of the second electrode, the refractive index n3 of the material of the optical extraction layer, the thickness L3 of the optical extraction layer, the refractive index n4 of the material of the protective layer, the thickness L4 of the protective layer, the refractive index n5 of the material of the first intercalation layer, and the thickness L5 of the first intercalation layer satisfy the following relationship: (n1L1+n3L3+n4L4+n5L5) / (L1+L3+L4+L5)=K

[0015] Among them, the range of K is 1.5 to 2.0.

[0016] According to some exemplary embodiments, a refractive index n1 of a material of the second electrode and a refractive index n3 of a material of the optical extraction layer satisfy |n1-n3|>1.

[0017] According to some exemplary embodiments, a relationship between a refractive index n4 of the material of the protective layer and a refractive index n3 of the material of the optical extraction layer satisfies |n4-n3|>0.3.

[0018] According to some exemplary embodiments, the relationship between the refractive index n5 of the material of the first intercalation layer and the refractive index n4 of the material of the protective layer satisfies |n5-n4|>0.2.

[0019] According to some exemplary embodiments, the encapsulation layer includes: a first inorganic layer located on a side of the protective layer away from the base substrate; an organic layer located on a side of the first inorganic layer away from the base substrate; and a second inorganic layer located on a side of the organic layer away from the base substrate.

[0020] According to some exemplary embodiments, the refractive index n1 of the material of the second electrode, the thickness L1 of the second electrode, the refractive index n3 of the material of the optical extraction layer, the thickness L3 of the optical extraction layer, the refractive index n4 of the material of the protective layer, and the thickness L4 of the protective layer satisfy the following relationship: (n1L1+n3L3+n4L4) / (L1+L3+L4)=K

[0021] Among them, K is 1.5.

[0022] According to some exemplary embodiments, a product n3·L3 of a refractive index n3 of a material of the optical extraction layer and a thickness L3 of the optical extraction layer is in a range of 90 to 120.

[0023] According to some exemplary embodiments, the refractive index n3 of the material of the optical extraction layer satisfies n3>1.7.

[0024] According to some exemplary embodiments, a product n2·L2 of a refractive index n2 of a material of the second intercalation layer and a thickness L2 of the second intercalation layer is in a range of 130 to 190.

[0025] According to some exemplary embodiments, the refractive index n2 of the material of the second intercalation layer satisfies 1.5<n2<1.8.

[0026] According to some exemplary embodiments, a product n4·L4 of a refractive index n4 of a material of the protective layer and a thickness L4 of the protective layer is in a range of 56 to 84.

[0027] According to some exemplary embodiments, the refractive index n4 of the material of the protective layer satisfies 1.4<n4<1.5.

[0028] According to some exemplary embodiments, a product n1·L1 of a refractive index n1 of a material of the second electrode and a thickness L1 of the second electrode is in a range of 1.28 to 1.92.

[0029] According to some exemplary embodiments, the above-mentioned display substrate may further include: a hole injection layer located on the side of the first electrode away from the base substrate; a first hole transport layer located on the side of the hole injection layer away from the base substrate; a second light-emitting layer located on the side of the first hole transport layer away from the base substrate; a second hole blocking layer located on the side of the second light-emitting layer away from the base substrate; a second electron transport layer located on the side of the second hole blocking layer away from the base substrate; a charge generation layer located on the side of the second electron transport layer away from the base substrate; and a second hole transport layer located on the side of the charge generation layer away from the base substrate, wherein the first light-emitting layer is located on the side of the second hole transport layer away from the base substrate.

[0030] According to some exemplary embodiments, the material of the first electrode includes at least one of silver, indium tin oxide / silver / indium tin oxide, and nickel-chromium alloy; the material of the second electrode includes at least one of transparent conductive oxide, magnesium-silver alloy, aluminum, magnesium, and silver.

[0031] According to some exemplary embodiments, S drop ≤ 0, and S drop is obtained by: S drop = ((S split - S ref.) / S ref.) * 100%

[0032] Wherein, S split is the color gamut area enclosed by the display substrate in the color space coordinates, S ref. is the color gamut area enclosed by the reference display substrate in the color space coordinates, and S drop is the change of split S relative to S ref.

[0033] In another aspect, a display device is provided, comprising the display substrate as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other objects and advantages of the present disclosure will become apparent from the following description of the present disclosure with reference to the accompanying drawings, which will help to provide a comprehensive understanding of the present disclosure.

[0035] FIG1A is a schematic diagram of a display substrate according to an embodiment of the present disclosure;

[0036] FIG1B is a schematic diagram of a laminated display substrate according to an embodiment of the present disclosure;

[0037] FIG1C is a schematic diagram of a display substrate including a plurality of first light-emitting layers according to an embodiment of the present disclosure;

[0038] FIG2 is a schematic diagram of an encapsulation layer according to an embodiment of the present disclosure;

[0039] FIG3A is a schematic diagram showing an improvement in color shift effect when the encapsulation layer is as shown in FIG2 according to an embodiment of the present disclosure;

[0040] FIG3B shows the relationship between the amount of color shift change and the size of the display substrate according to an embodiment of the present disclosure;

[0041] FIG4 is a schematic diagram of an encapsulation layer according to another embodiment of the present disclosure;

[0042] FIG5 is a schematic diagram showing an improvement in the color shift effect when the encapsulation layer is as shown in FIG4 according to an embodiment of the present disclosure;

[0043] FIG6 is a schematic diagram of an encapsulation layer according to another embodiment of the present disclosure;

[0044] FIG7A is a schematic diagram showing an improvement in color shift effect when the encapsulation layer is as shown in FIG6 according to an embodiment of the present disclosure;

[0045] FIG7B is a diagram showing the relationship between the effective thickness and the amount of color shift change when the encapsulation layer is as shown in FIG6 according to an embodiment of the present disclosure;

[0046] FIG8A is a schematic diagram showing how the color shift effect is improved when only the second intercalation layer is adjusted according to an embodiment of the present disclosure;

[0047] FIG8B is a graph showing the relationship between the effective thickness and the amount of color shift change when only the second intercalation layer is adjusted according to an embodiment of the present disclosure;

[0048] FIG9A is a schematic diagram showing how the color shift effect is improved when only the protective layer is adjusted according to an embodiment of the present disclosure;

[0049] FIG. 9B is a graph showing the relationship between the effective thickness and the amount of color shift change when only the protective layer is adjusted according to an embodiment of the present disclosure.

[0050] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the sizes of layers, structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0051] The technical solution of the present disclosure is further described in detail below through examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present disclosure with reference to the accompanying drawings is intended to explain the overall inventive concept of the present disclosure and should not be construed as limiting the present disclosure.

[0052] Furthermore, in the following detailed description, for ease of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it will be apparent that one or more embodiments can be practiced without these specific details.

[0053] It should be understood that, although the terms first, second, etc. can be used here to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the exemplary embodiments, the first element can be named as the second element, and similarly, the second element can be named as the first element. As used herein, the term "and / or" includes any combination and all combinations of one or more related listed items.

[0054] It should be understood that when an element or layer is referred to as being "formed on" another element or layer, the element or layer may be formed directly or indirectly on the other element or layer. That is, for example, there may be intermediate elements or intermediate layers. Conversely, when an element or layer is referred to as being "formed directly on" another element or layer, there are no intermediate elements or intermediate layers. Other terms used to describe the relationship between elements or layers (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.) should be interpreted in a similar manner.

[0055] In this document, unless otherwise specified, the phrase "located on the same layer" generally means that the first component and the second component can be made of the same material and can be formed by the same patterning process. The phrase "A and B are integrally connected" means that component A and component B are integrally formed, that is, they generally include the same material and form a structurally continuous, unitary component.

[0056] Unless otherwise specified, directional terms such as "upper," "lower," "left," "right," "inner," and "outer" are used herein to indicate positions or relationships based on the figures shown. These terms are intended solely to facilitate the description of the present disclosure and are not intended to indicate or imply that the devices, components, or parts referred to must have, be constructed, or operate in a specific orientation. It should be understood that when the absolute positions of the objects being described change, the relative positions they represent may also change accordingly. Therefore, these directional terms should not be construed as limiting the present disclosure.

[0057] In this article, the expressions "vertical", "vertically connected" or similar expressions include not only the case of 90 degrees, that is, the case of complete verticality, but also the case where the difference from 90 degrees is within a certain error range, for example, the case where the difference from 90 degrees is within the process error range.

[0058] Those skilled in the art should understand that, in this article, unless otherwise specified, the expression "height" or "thickness" refers to the dimension of the surface of each film layer arranged perpendicular to the display substrate, that is, the dimension along the light emitting direction of the display substrate, or the dimension along the normal direction of the display device.

[0059] In this document, the directional expressions "first direction" and "second direction" are used to describe different directions along a pixel unit, such as the longitudinal and transverse directions of a pixel unit, or the row and column directions of a sub-pixel arrangement. It should be understood that such expressions are merely exemplary descriptions and are not intended to limit the present disclosure.

[0060] OLED organic materials are generally prepared by evaporation, and the accuracy of the preparation process affects the difference in film thickness uniformity. The greater the fluctuation in film thickness, the greater the impact on screen display uniformity, that is, the color deviation of different points, the larger the scattered point distribution (margin) area at a fixed angle. The color deviation phenomenon is more obvious on the display screen of a notebook or a car terminal. For example, on such a display screen, when displaying 9 or 135 points, the point difference is particularly obvious. In order to improve the color deviation phenomenon, if the color deviation is improved only by improving the process capability of the equipment, it is difficult to achieve a significant color deviation improvement effect due to the hardware limitations of the equipment.

[0061] In view of this, the embodiments of the present disclosure provide multiple sets of embodiments regarding OLED structures to effectively improve color shift. Specifically, since the pixels of OLED panels are mostly R (Red), G (Green), and B (Blue) sub-pixel structures, the color shift of white light is affected by the RGB variation pattern. The principle of improving color shift by setting different OLED structures is that by adjusting the degree of influence of RGB on the color shift of white light, that is, the sensitivity of the single colors, the color shift under the white light angle can be adjusted, thereby improving the color shift difference at different points of the product.

[0062] Specifically, an embodiment of the present disclosure provides a display substrate, comprising: a base substrate; a first electrode located on the base substrate; a first light-emitting layer located on a side of the first electrode away from the base substrate; a first hole blocking layer located on a side of the first light-emitting layer away from the base substrate; a first electron transport layer located on a side of the first hole blocking layer away from the base substrate; an electron injection layer located on a side of the first electron transport layer away from the base substrate; a second electrode located on a side of the electron injection layer away from the base substrate; an optical extraction layer located on a side of the second electrode away from the base substrate; a protective layer located on a side of the optical extraction layer away from the base substrate; and an encapsulation layer located on a side of the protective layer away from the base substrate, wherein the refractive index of the material of the optical extraction layer is greater than the refractive index of the material of the protective layer, and the refractive index of the material of the protective layer is greater than the refractive index of the material of the second electrode.

[0063] FIG. 1A is a schematic diagram of a display substrate according to an embodiment of the present disclosure.

[0064] As shown in Figure 1, the display substrate 1 may include a base substrate 11; a first electrode 12 located on the base substrate 11; a first light-emitting layer 13 located on the side of the first electrode 12 away from the base substrate 11; a first hole blocking layer 14 located on the side of the first light-emitting layer 13 away from the base substrate 11; a first electron transport layer 15 located on the side of the first hole blocking layer 14 away from the base substrate 11; an electron injection layer 16 located on the side of the first electron transport layer 15 away from the base substrate 11; a second electrode 17 located on the side of the electron injection layer 16 away from the base substrate 11; an optical extraction layer 18 located on the side of the second electrode 17 away from the base substrate 11; a protective layer 19 located on the side of the optical extraction layer 18 away from the base substrate 11; and an encapsulation layer 20 located on the side of the protective layer 19 away from the base substrate, wherein the refractive index of the material of the optical extraction layer 18 is greater than the refractive index of the material of the protective layer 19, and the refractive index of the material of the protective layer 19 is greater than the refractive index of the material of the second electrode 17.

[0065] According to an embodiment of the present disclosure, the first electrode 12 can be used as an anode, and the second electrode 17 can be used as a cathode. The display substrate provided in the embodiment of the present disclosure can be a top-emitting device. Therefore, the anode and cathode can both adopt the anode and cathode materials of the top-emitting OLED device in the prior art. The anode material and cathode material of the embodiment of the present disclosure can be adaptively adjusted according to actual needs. For example, the material of the first electrode can include at least one of silver (Ag), indium tin oxide / silver / indium tin oxide (ITO / Ag / ITO) or nickel-chromium alloy (Ni:Cr alloy). The material of the second electrode 17 can be selected from at least one of transparent conductive oxides, magnesium-silver alloys, aluminum, magnesium, and silver, such as transparent conductive oxides such as ITO, and Mg / Ag / Al / or alloys can also be preferred.

[0066] According to an embodiment of the present disclosure, the first light-emitting layer 13 may include a structure of R, G, and B sub-pixels, wherein the R sub-pixels may serve as the first sub-light-emitting layer, the G sub-pixels may serve as the second sub-light-emitting layer, and the B sub-pixels may serve as the third sub-light-emitting layer.

[0067] According to the embodiments of the present disclosure, the color shift improvement solution of the present application can be applied to top-emitting devices, because a structure that enhances microcavity refraction may exist in the top-emitting device, thereby improving the color shift phenomenon of the display substrate.

[0068] According to an embodiment of the present disclosure, the encapsulation layer may include at least one of a first intercalation layer, a first inorganic layer, a second intercalation layer, an organic layer, and a second inorganic layer. By adjusting the color deviation of one or more layers among the optical removal layer 18, the protective layer 19, and the encapsulation layer 20, the color deviation phenomenon of the display substrate can be improved.

[0069] According to the embodiment of the present disclosure, a hole injection layer 21 , a hole transport layer 22 , etc. may be provided between the first electrode 12 and the first light emitting layer 13 as needed, which will not be described in detail here.

[0070] FIG. 1B is a schematic diagram of a laminated display substrate according to an embodiment of the present disclosure.

[0071] As shown in FIG1B , the display substrate 1 may further include a hole injection layer 21 located on the side of the first electrode 12 away from the base substrate 11; a first hole transport layer 221 located on the side of the hole injection layer 21 away from the base substrate 11; a second light-emitting layer 25 located on the side of the first hole transport layer 221 away from the base substrate 11; a second hole blocking layer 26 located on the side of the second light-emitting layer 25 away from the base substrate 11; a second electron transport layer 27 located on the side of the second hole blocking layer 26 away from the base substrate 11; a charge generation layer 28 located on the side of the second electron transport layer 27 away from the base substrate 11; and a second hole transport layer 222 located on the side of the charge generation layer 28 away from the base substrate 11, wherein the first light-emitting layer 13 is located on the side of the second hole transport layer 222 away from the base substrate 11. The charge generation layer 28 may include an N-type charge generation layer 281 and a P-type charge generation layer 282. It is understood that the color shift improvement solution provided in the embodiments of the present disclosure may also be applied to the stacked device shown in FIG1B .

[0072] FIG1C is a schematic diagram of a display substrate including a plurality of first light-emitting layers according to an embodiment of the present disclosure.

[0073] The first light-emitting layer 13 in the display substrate 1 can be provided as a single layer or multiple layers, as shown in FIG1C . The main difference between FIG1C and FIG1A is that two first light-emitting layers 13 are provided in FIG1C , as well as an electron generation layer 23, a hole generation layer 24, a hole transport layer 22, etc., which are correspondingly provided between the two first light-emitting layers. Optionally, three first light-emitting layers stacked in sequence can also be provided in the display substrate, and accordingly, electron generation layers, hole generation layers, hole transport layers and other structures can be provided between the light-emitting layers according to actual needs. No further details will be given here. It can be understood that the solution for improving color deviation provided in the embodiment of the present disclosure can be applied to a display substrate having a single light-emitting layer structure, and can also be applied to a display substrate having multiple superimposed light-emitting layers.

[0074] According to an embodiment of the present disclosure, one or more of the optical extraction layer 18, the protective layer 19, and the encapsulation layer 20 can be used as a color deviation adjustment layer to improve the color deviation phenomenon of the display substrate. The relationship between the color deviation adjustment layer and the second electrode 17 can satisfy the relationship shown in formula (1). ∑(n i L i ) / ∑L i =K (1)

[0075] Wherein, n may represent the refractive index of the material of each layer, L may represent the thickness of each layer, i is a positive integer, and K is greater than 1.

[0076] FIG. 2 is a schematic diagram of an encapsulation layer according to an embodiment of the present disclosure.

[0077] As shown in FIG2 , the encapsulation layer 20 may include a first inorganic layer 201 located on the side of the protective layer 19 away from the base substrate 11; a second intercalation layer 202 located on the side of the first inorganic layer 201 away from the base substrate 11; an organic layer 203 located on the side of the second intercalation layer 202 away from the base substrate 11; and a second inorganic layer 204 located on the side of the organic layer 203 away from the base substrate 11. The "..." in FIG2 may indicate a film layer structure omitted between the base substrate 11 and the protective layer 19.

[0078] According to an embodiment of the present disclosure, when the encapsulation layer 20 includes the first inorganic layer 201, the second intercalation layer 202, the organic layer 203, and the second inorganic layer 204, the second electrode 17 and the second intercalation layer 202 can serve as a color shift adjustment layer to improve the color shift phenomenon of the display substrate. Specifically, the refractive index n1 of the material of the second electrode 17, the thickness L1 of the second electrode 17, the refractive index n2 of the material of the second intercalation layer 202, and the thickness L2 of the second intercalation layer 202 can satisfy the relationship shown in formula (2). (n1L1+n2L2) / (L1+L2)=K (2)

[0079] The range of K may be 1.3 to 1.6, and the refractive index n1 of the material of the second electrode 17 and the refractive index n2 of the material of the second intercalation layer 202 may satisfy |n1-n2|>1.

[0080] The material of the second intercalation layer 202 can be an organic or inorganic film layer such as SiN, SiON, etc. Preferably, the refractive index n1 of the material of the second electrode 17 is in the range of 0.14 to 0.18, the refractive index n2 of the material of the second intercalation layer 202 can be in the range of 1.5 to 1.8, the thickness L1 of the second electrode 17 can be in the range of 8 to 12 nm, and the thickness L2 of the second intercalation layer 202 can be in the range of 80 to 100 nm.

[0081] FIG. 3A is a schematic diagram showing an improvement in the color shift effect when the encapsulation layer is as shown in FIG. 2 according to an embodiment of the present disclosure.

[0082] As shown in Figure 3A, the horizontal and vertical coordinates represent the horizontal and vertical coordinates in the color space, respectively. In two-dimensional space, the color coordinates of a pixel can be determined by one horizontal coordinate and one vertical coordinate. In Figure 3A, the points in box A are the measured data of the pixel points on the substrate at the same viewing angle. The border of box A is the boundary obtained by fitting to match the experimental results. Box A can be an orange pixel. Box B is the data that can be used as a reference under the same experimental conditions as box A. The smaller the area of ​​box A, the smaller the color deviation, which can indicate that the color deviation phenomenon has been improved. To determine the improvement of the color deviation, the area of ​​box A and the area of ​​box B can be substituted into formula (3) to obtain the improvement result. S drop = ((S split-S ref.) / S ref.)*100% (3)

[0083] Here, S split represents the color gamut area enclosed by the display substrate in color space coordinates, which can be understood as the area of ​​frame A. S ref. represents the color gamut area enclosed by the reference display substrate in color space coordinates, which can be understood as the area of ​​frame B. S drop can be understood as the change in split S relative to S ref. Ref. S drop = 0% is the minimum standard, and a negative S drop value indicates improved color shift. In the above embodiment, the color shift improvement result can be: a color shift of 5.6 JNCD (Just Noticeable Color Difference, a standard for measuring screen color accuracy), a 47.8% improvement in color shift relative to the reference data.

[0084] According to the embodiments of the present disclosure, in Figure 3A, the CIE1931 (a mathematically defined color space) color gamut can cover up to 101% of the NTSC (a color standard). As the thickness of the second electrode 17 changes, the angular color shift of RGB can be simultaneously enhanced or weakened, resulting in a significant change in the color shift margin of the synthesized white light. The low refractive index of the second intercalation layer 202 can also adjust the large-angle color shift of red light, changing the sensitivity of red light to white light, thereby affecting the lateral distribution of scatter points.

[0085] When the second electrode 17 and the second intercalation layer 202 can serve as color shift adjustment layers, the peak of the spectrum of the first sub-light-emitting layer can be between 620nm and 640nm, the peak of the second sub-light-emitting layer can be between 515nm and 535nm, and the peak of the third sub-light-emitting layer can be between 445nm and 465nm. The influence of the thickness of the second electrode on the RGB spectrum of each light-emitting layer can be shown in formulas (4) to (6).

[0086] When the thickness L1 of the second electrode 17 is 8 to 16 nm, the following conditions are met: R_Peak wave = 1.04(L1) + 614 (4) G_Peak wave = 0.67L1 + 513 (5) B_Peak wave = 458 (L1 = 8 to 11 nm) or 459 (L1 = 12 to 16 nm) (6)

[0087] Among them, R_Peak wave can represent the peak position of the red light spectrum, G_Peak wave can represent the peak position of the green light spectrum, and B_Peak wave can represent the peak position of the blue light spectrum.

[0088] According to the embodiments of the present disclosure, the film layer structure between the first hole blocking layer 14 and the encapsulation layer 20 can form a microcavity. By matching and limiting the relationship between the thickness and the refractive index of the color deviation adjustment layer, the microcavity effect can be adjusted to reduce the area of ​​S spilt (which can be understood as the area of ​​box A in Figure 3A), thereby improving the color deviation phenomenon of the display substrate.

[0089] FIG. 3B shows the relationship between the amount of color shift change and the size of the display substrate according to an embodiment of the present disclosure.

[0090] As shown in Figure 3B, the horizontal axis can be the size of the display substrate, and the vertical axis can be the color shift change (Sdrop). For products of different sizes (inch, In), the relative relationship of Sdrop also varies to a certain extent. Under the same microcavity device and the same structural change conditions, the experimental results at different sizes show that Sdrop and In (size above 6 inches) have an approximately linear relationship as shown in Figure 3B. This approximate linear relationship can be expressed as formula (7). Sdrop = -0.0051 × In - 0.0713 (7)

[0091] Where Sdrop represents the amount of color shift change, and In represents the size of the display substrate. Formula (7) is applicable to the addition and subtraction of film layers inside the microcavity, stacked structures, multi-layer packaging structures, COE (Color filter on encapsulation, depositing a color filter layer after AMOLED (active matrix organic light-emitting diode) packaging), EES (Electrochemistry and Energy Storage) devices, and differences in film material.

[0092] FIG. 4 is a schematic diagram of an encapsulation layer according to another embodiment of the present disclosure.

[0093] As shown in FIG4 , the encapsulation layer 20 may include a first intercalation layer 205 located on the side of the protective layer 19 away from the base substrate 11; a first inorganic layer 201 located on the side of the first intercalation layer 205 away from the base substrate 11; an organic layer 203 located on the side of the first inorganic layer 201 away from the base substrate 11; and a second inorganic layer 204 located on the side of the organic layer 203 away from the base substrate 11. The “…” in FIG4 may indicate omitted film layer structures between the base substrate 11 and the protective layer 19.

[0094] According to an embodiment of the present disclosure, when the encapsulation layer 20 includes the first intercalation layer 205, the first inorganic layer 201, the organic layer 203, and the second inorganic layer 204, the second electrode 17, the optical extraction layer 18, the protective layer 19, and the first intercalation layer 205 can serve as a color shift adjustment layer to improve the color shift phenomenon of the display substrate. Specifically, the refractive index n1 of the material of the second electrode 17, the thickness L1 of the second electrode 17, the refractive index n3 of the material of the optical extraction layer 18, the thickness L3 of the optical extraction layer 18, the refractive index n4 of the material of the protective layer 19, the thickness L4 of the protective layer 19, the refractive index n5 of the material of the first intercalation layer 205, and the thickness L5 of the first intercalation layer 205 can satisfy the relationship shown in formula (8). (n1L1+n3L3+n4L4+n5L5) / (L1+L3+L4+L5)=K (8)

[0095] Among them, the range of K can be 1.5 to 2.0; the refractive index n1 of the material of the second electrode 17 and the refractive index n3 of the material of the optical extraction layer 18 can satisfy |n1-n3|>1; the relationship between the refractive index n4 of the material of the protective layer 19 and the refractive index n3 of the material of the optical extraction layer 18 can satisfy |n4-n3|>0.3; the relationship between the refractive index n5 of the material of the first intercalation layer 205 and the refractive index n4 of the material of the protective layer 19 can satisfy |n5-n4|>0.2.

[0096] According to the embodiments of the present disclosure, the optical extraction layer 18 can be made of an organic material, while the first intercalation layer 205 can be made of an inorganic film such as SiN or SiON. As an organic layer, the optical extraction layer 18 can have a refractive index of 1.8 or higher. The refractive index for short wavelengths is greater than that for long wavelengths, making the optical extraction layer 18 relatively sensitive to blue light. The refractive index of the auxiliary light extraction layer is generally set below 1.5 to effectively adjust color shift at large angles.

[0097] FIG. 5 is a schematic diagram showing how the color shift effect is improved when the encapsulation layer is as shown in FIG. 4 according to an embodiment of the present disclosure.

[0098] As shown in Figure 5, the CIE1931 color gamut covers a maximum of 99.2% NTSC. The points in frame C represent the measured data of the pixels on the display substrate at the same viewing angle. The border of frame C is the boundary obtained by fitting to match the experimental results. Frame C can contain green pixels. Frame D represents the data that can be used as a reference under the same experimental conditions as frame C. The smaller the area of ​​frame C, the smaller the color deviation, indicating that the color shift phenomenon has been improved. To determine the improvement in color shift, the area of ​​frame C can be used as S split and the area of ​​frame D as S ref. and these can be substituted into formula (3) to obtain the color shift improvement result, S drop. In this embodiment, the obtained S drop is -25%, and K is 1.52.

[0099] In this embodiment, the peak position of the spectrum of the first sub-light-emitting layer can be between 615nm and 635nm, the peak position of the second sub-light-emitting layer can be between 510nm and 530nm, and the peak position of the third sub-light-emitting layer can be between 450nm and 465nm. The influence of the thickness of the second electrode on the RGB spectrum of each light-emitting layer can be shown as formulas (9) to (11).

[0100] When the thickness L1 of the second electrode 17 is between 8 and 16 nm, the following is true: R_Peak wave = 0.36(L1) + 626 (9) G_Peak wave = 547(8-12 nm) & 546(13-16 nm) (10) B_Peak wave = 458(8-12 nm) & 459(13-16 nm) (11)

[0101] Among them, R_Peak wave can represent the peak position of the red light spectrum, G_Peak wave can represent the peak position of the green light spectrum, and B_Peak wave can represent the peak position of the blue light spectrum.

[0102] According to an embodiment of the present disclosure, the thickness and refractive index of each film layer are adjusted to reduce the area of ​​S spilt (which can be understood as the area of ​​frame C in FIG. 5 ), thereby improving the color shift phenomenon of the display substrate.

[0103] FIG. 6 is a schematic diagram of an encapsulation layer according to another embodiment of the present disclosure.

[0104] As shown in FIG6 , the encapsulation layer 20 may include a first inorganic layer 201 located on the side of the protective layer 19 away from the base substrate 11; an organic layer 203 located on the side of the first inorganic layer 201 away from the base substrate 11; and a second inorganic layer 204 located on the side of the organic layer 203 away from the base substrate 11. The “…” in FIG6 may indicate a film structure omitted between the base substrate 11 and the protective layer 19.

[0105] According to an embodiment of the present disclosure, when the encapsulation layer 20 includes the first inorganic layer 201, the organic layer 203, and the second inorganic layer 204, the optical extraction layer 18 is improved so that the characteristics of the second electrode 17, the optical extraction layer 18, and the protective layer 19 should satisfy the relationship shown in formula (12). Specifically, the refractive index n1 of the material of the second electrode 17, the thickness L1 of the second electrode 17, the refractive index n3 of the material of the optical extraction layer 18, the thickness L3 of the optical extraction layer 18, the refractive index n4 of the material of the protective layer 19, and the thickness L4 of the protective layer 19 can satisfy the relationship shown in formula (12). (n1L1+n3L3+n4L4) / (L1+L3+L4)=K (12)

[0106] Here, K can be 1.5.

[0107] The product of the film's refractive index and thickness is defined as the effective thickness Leff. In this embodiment, the product n3·L3 of the optical extraction layer 18's material refractive index n3 and its thickness L3 (n3·L3) can range from 90 to 120, with the refractive index n3 satisfying n3>1.7. The optical extraction layer 18 can be made of either organic or inorganic high-refractive materials. The refractive index of the optical extraction layer 18 at short wavelengths is greater than that at long wavelengths, resulting in a relatively high sensitivity to blue light.

[0108] FIG. 7A is a schematic diagram showing an improvement in the color shift effect when the encapsulation layer is as shown in FIG. 6 according to an embodiment of the present disclosure.

[0109] As shown in Figure 7A, the CIE1931 color gamut covers a maximum of 100% NTSC. The points in frame E represent the measured data of the pixels on the display substrate at the same viewing angle. The border of frame E is the boundary obtained by fitting to match the experimental results. Frame E may contain blue pixels. Frame F represents reference data under the same experimental conditions as frame E. The smaller the area of ​​frame E, the smaller the color deviation, indicating improved color deviation. To determine the improvement in color deviation, the area of ​​frame E can be used as S split and the area of ​​frame F as S ref., and these can be substituted into formula (3) to obtain the color deviation improvement result, S drop. In this embodiment, the obtained S drop is -54.8%, and the effective thickness Leff at this time can be 108.

[0110] FIG. 7B is a graph showing the relationship between the effective thickness and the amount of color shift change when the encapsulation layer is as shown in FIG. 6 according to an embodiment of the present disclosure.

[0111] As shown in FIG7B , the horizontal axis can be the effective thickness (Leff), and the vertical axis can be the color shift change (Sdrop). The relationship between the effective thickness and Sdrop can be shown in formula (13). Sdrop = -1E-05(Leff) 3 +0.0057(Leff) 2 +0.7069(Leff)+27.64 (13)

[0112] 7 , the film characteristics of the optical extraction layer 18 for improving color shift should satisfy 90<Leff<120, n3>1.7.

[0113] In this embodiment, the spectral peak position of the first sub-light emitting layer may be between 623nm and 646nm, the peak position of the second sub-light emitting layer may be between 520nm and 535nm, and the peak position of the third sub-light emitting layer may be between 450nm and 465nm.

[0114] 2 , different from the previous embodiment, the second intercalation layer 202 can be used as a color shift adjustment layer. The color shift phenomenon of the display substrate can be improved by simply adjusting the refractive index and thickness of the second intercalation layer 202 .

[0115] According to the embodiments of the present disclosure, the material of the second intercalation layer 202 is preferably an inorganic film layer such as SiN or SiON, and the refractive index n2 of the second intercalation layer 202 can range from 1.5 to 1.8. The film layer within the encapsulation film layer, which regulates light emission, has a low refractive index and can have a convergent effect on adjusting RGB color shifts at large angles.

[0116] FIG8A is a schematic diagram illustrating improvement in color shift effect when only the second intercalation layer is adjusted according to an embodiment of the present disclosure; FIG8B is a graph illustrating the relationship between effective thickness and color shift change when only the second intercalation layer is adjusted according to an embodiment of the present disclosure.

[0117] As shown in Figure 8A, the points in frame G represent the measured data of the pixels on the display substrate at the same viewing angle. The border of frame G is the boundary obtained by fitting to match the experimental results. Frame G may contain blue pixels. Frame H represents reference data under the same experimental conditions as frame G. The smaller the area of ​​frame G, the smaller the color deviation, indicating improved color deviation. To determine the improvement in color deviation, the area of ​​frame G can be used as S split and the area of ​​frame H as S ref., and these can be substituted into formula (3) to obtain the color deviation improvement result, S drop. In this embodiment, the obtained S drop is -63%, and the effective thickness Leff at this time can be 163.

[0118] As shown in FIG8B , the horizontal axis can be the effective thickness (Leff), and the vertical axis can be the color shift change (Sdrop). The relationship between the effective thickness and Sdrop can be shown in formula (14). Sdrop = 0.0002 (Leff) 2 +0.0513(Leff)+3.32 (14)

[0119] 8B , the film characteristics of the second intercalation layer 202 with improved color shift should satisfy 130<Leff<190, that is, the product n2·L2 of the refractive index n2 of the material of the second intercalation layer 202 and the thickness L2 of the second intercalation layer 202 can be in the range of 130 to 190; the refractive index n2 of the material of the second intercalation layer can be between 1.5 and 1.8.

[0120] In this embodiment, the spectral peak position of the first sub-light emitting layer may be between 615nm and 635nm, the peak position of the second sub-light emitting layer may be between 515nm and 535nm, and the peak position of the third sub-light emitting layer may be between 450nm and 460nm.

[0121] 6 , different from the previous embodiment, the protective layer 19 can be used as a color shift adjustment layer. The color shift phenomenon of the display substrate can be improved by simply adjusting the refractive index and thickness of the protective layer 19 .

[0122] According to the embodiment of the present disclosure, the protective layer 19 can be used as a low-refractive-index film layer. Since it is close to the second electrode 17 , it has a more direct impact on the microcavity characteristics, thereby effectively adjusting the color shift difference at a large angle.

[0123] FIG9A is a schematic diagram illustrating improvement in color shift effect when only the protective layer is adjusted according to an embodiment of the present disclosure; FIG9B is a diagram illustrating the relationship between effective thickness and color shift change when only the protective layer is adjusted according to an embodiment of the present disclosure.

[0124] As shown in Figure 9A, the points in Frame I represent the measured data of the pixels on the display substrate at the same viewing angle. The border of Frame I is the boundary obtained by fitting to match the experimental results. Frame I may contain blue pixels. Frame J represents the data that can be used as a reference under the same experimental conditions as Frame I. The smaller the area of ​​Frame I, the smaller the color deviation, indicating that the color deviation has improved. To determine the improvement in color deviation, the area of ​​Frame I can be used as S split and the area of ​​Frame J as S ref., and these can be substituted into Formula (3) to obtain the color deviation improvement result, S drop. In this embodiment, S drop is improved by 38.5% relative to S ref., and the effective thickness Leff can be 70.

[0125] As shown in FIG9B , the horizontal axis can be the effective thickness (Leff), and the vertical axis can be the color shift change (Sdrop). The relationship between the effective thickness and Sdrop can be shown in formula (15). Sdrop = 0.0001 (Leff) 2 -0.0182(Leff)+0.2391 (15)

[0126] Continuing with Figure 9B , the film characteristics of the protective layer 19 for color shift improvement should satisfy 56 < Leff < 84. Specifically, the product n4·L4 (the refractive index n4 of the protective layer 19 material) and its thickness L4 can be in the range of 56 to 84. The refractive index n4 of the protective layer 19 material can be between 1.4 and 1.5. Optimal color shift improvement can be achieved by maintaining the Leff of the second electrode 17 within the range of 1.28 to 1.92, i.e., by ensuring that the product n1·L1 (the refractive index n1 of the second electrode 17 material) and its thickness L1 is between 1.28 and 1.92.

[0127] In this embodiment, the spectral peak position of the first sub-light emitting layer may be between 620nm and 635nm, the peak position of the second sub-light emitting layer may be between 510nm and 530nm, and the peak position of the third sub-light emitting layer may be between 445nm and 465nm.

[0128] The embodiments provided in the present disclosure can be applied to OLED film layer structures (including the increase or decrease of film layers inside a microcavity, multiple light-emitting stacked structures, etc.), multi-layer packaging structures, as well as COE, EES devices, QLED (Quantum Dot Light Emitting Diodes) and other structures. The difference in film layer materials is only a difference from the Ref. reference data, and does not affect the film thickness fluctuations caused by the same process level and the law of film layer changes.

[0129] According to the embodiments of the present disclosure, by setting the thickness and refractive index of the film layer of the display substrate, the technical effect of improving color deviation can be achieved, thereby solving the probability of excessive dispersion caused by color deviation differences at multiple points on the display screen, and improving the display and yield of the display substrate as a whole.

[0130] The present disclosure also provides a display device, which may include the display substrate described in any of the above embodiments. The display device may be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigation system.

[0131] It should be understood that the display device provided by the embodiment of the present disclosure includes the above-mentioned display substrate, and the beneficial effects of the display device are the same as the beneficial effects of the above-mentioned display substrate, which will not be repeated here.

[0132] Although some embodiments of the present general inventive concept have been illustrated and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A display substrate, characterized in that: include: substrate substrate; a first electrode located on the substrate; A first light-emitting layer located on a side of the first electrode away from the base substrate; A first hole blocking layer located on a side of the first light-emitting layer away from the base substrate; A first electron transport layer located on a side of the first hole blocking layer away from the substrate; An electron injection layer located on a side of the first electron transport layer away from the substrate; A second electrode located on a side of the electron injection layer away from the substrate; An optical extraction layer located on a side of the second electrode away from the base substrate; A protective layer located on a side of the optical extraction layer away from the substrate; as well as an encapsulation layer located on a side of the protective layer away from the substrate, The refractive index of the material of the optical extraction layer is greater than the refractive index of the material of the protective layer, and the refractive index of the material of the protective layer is greater than the refractive index of the material of the second electrode.

2. The display substrate according to claim 1, characterized in that: The display substrate includes a color deviation adjustment layer, the color deviation adjustment layer is selected from at least one of the optical extraction layer, the protective layer and the encapsulation layer, and the color deviation adjustment layer and the second electrode satisfy the following relationship: ∑(n i L i ) / ∑L i =K, Wherein, n represents the refractive index of the material of each layer, L represents the thickness of each layer, i is a positive integer, and K is greater than 1.

3. The display substrate according to claim 2, characterized in that: The encapsulation layer comprises: A first inorganic layer located on a side of the protective layer away from the substrate; A second intercalation layer located on a side of the first inorganic layer away from the substrate; an organic layer located on a side of the second intercalation layer away from the substrate; A second inorganic layer is located on a side of the organic layer away from the base substrate.

4. The display substrate according to claim 3, characterized in that: The refractive index n1 of the material of the second electrode, the thickness L1 of the second electrode, the refractive index n2 of the material of the second intercalation layer and the thickness L2 of the second intercalation layer satisfy the following relationship: (n1L1+n2L2) / (L1+L2)=K, Among them, the range of K is 1.3 to 1.

6.

5. The display substrate according to claim 4, characterized in that: The refractive index n1 of the material of the second electrode and the refractive index n2 of the material of the second intercalation layer satisfy |n1-n2|>1.

6. The display substrate according to claim 2, characterized in that: The encapsulation layer comprises: A first intercalation layer located on a side of the protective layer away from the substrate; A first inorganic layer located on a side of the first intercalation layer away from the substrate; an organic layer located on a side of the first inorganic layer away from the base substrate; A second inorganic layer is located on a side of the organic layer away from the base substrate.

7. The display substrate according to claim 6, characterized in that: The refractive index n1 of the material of the second electrode, the thickness L1 of the second electrode, the refractive index n3 of the material of the optical extraction layer, the thickness L3 of the optical extraction layer, the refractive index n4 of the material of the protective layer, the thickness L4 of the protective layer, the refractive index n5 of the material of the first intercalation layer and the thickness L5 of the first intercalation layer satisfy the following relationship: (n1L1+n3L3+n4L4+n5L5) / (L1+L3+L4+L5)=K Among them, the range of K is 1.5 to 2.

0.

8. The display substrate according to claim 7, characterized in that: The refractive index n1 of the material of the second electrode and the refractive index n3 of the material of the optical extraction layer satisfy |n1-n3|>1.

9. The display substrate according to claim 7, characterized in that: The relationship between the refractive index n4 of the material of the protective layer and the refractive index n3 of the material of the optical extraction layer satisfies |n4-n3|>0.

3.

10. The display substrate according to claim 7, characterized in that: The relationship between the refractive index n5 of the material of the first intercalation layer and the refractive index n4 of the material of the protective layer satisfies |n5-n4|>0.

2.

11. The display substrate according to claim 2, characterized in that: The encapsulation layer comprises: A first inorganic layer located on a side of the protective layer away from the substrate; an organic layer located on a side of the first inorganic layer away from the base substrate; A second inorganic layer is located on a side of the organic layer away from the base substrate.

12. The display substrate according to claim 11, characterized in that: The refractive index n1 of the material of the second electrode, the thickness L1 of the second electrode, the refractive index n3 of the material of the optical extraction layer, the thickness L3 of the optical extraction layer, the refractive index n4 of the material of the protective layer and the thickness L4 of the protective layer satisfy the following relationship: (n1L1+n3L3+n4L4) / (L1+L3+L4)=K Among them, K is 1.

5.

13. The display substrate according to claim 11, characterized in that: The product n3·L3 of the refractive index n3 of the material of the optical extraction layer and the thickness L3 of the optical extraction layer is in the range of 90 to 120.

14. The display substrate according to claim 11, characterized in that: The refractive index n3 of the material of the optical extraction layer satisfies n3>1.

7.

15. The display substrate according to claim 3, characterized in that: The product n2·L2 of the refractive index n2 of the material of the second intercalation layer and the thickness L2 of the second intercalation layer is in the range of 130-190.

16. The display substrate according to claim 15, characterized in that: The refractive index n2 of the material of the second intercalation layer satisfies 1.5<n2<1.

8.

17. The display substrate according to claim 11, characterized in that: The product n4·L4 of the refractive index n4 of the material of the protective layer and the thickness L4 of the protective layer is in the range of 56 to 84.

18. The display substrate according to claim 17, characterized in that: The refractive index n4 of the material of the protective layer satisfies 1.4<n4<1.

5.

19. The display substrate according to claim 17, characterized in that: The product n1·L1 of the refractive index n1 of the material of the second electrode and the thickness L1 of the second electrode is in the range of 1.28 to 1.

92.

20. The display substrate according to claim 1, further comprising: a hole injection layer located on a side of the first electrode away from the substrate; A first hole transport layer located on a side of the hole injection layer away from the substrate; A second light-emitting layer located on a side of the first hole transport layer away from the base substrate; A second hole blocking layer located on a side of the second light emitting layer away from the base substrate; A second electron transport layer located on a side of the second hole blocking layer away from the substrate; A charge generation layer located on a side of the second electron transport layer away from the substrate; A second hole transport layer is located on a side of the charge generation layer away from the substrate, wherein the first light emitting layer is located on a side of the second hole transport layer away from the substrate.

21. The display substrate according to any one of claims 1 to 20, characterized in that: The material of the first electrode includes at least one of silver, indium tin oxide / silver / indium tin oxide, and nickel-chromium alloy; The material of the second electrode includes at least one of transparent conductive oxide, magnesium-silver alloy, aluminum, magnesium, and silver.

22. The display substrate according to any one of claims 1 to 20, characterized in that: S drop≤0, S drop is obtained by: S drop=((S split-S ref.) / S ref.)*100% Wherein, S split is the color gamut area enclosed by the display substrate in the color space coordinates, S ref. is the color gamut area enclosed by the reference display substrate in the color space coordinates, and S drop is the change of split S relative to S ref.

23. A display device, characterized in that: The invention comprises the display substrate according to any one of claims 1 to 22.

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