Display substrate, display panel, and display apparatus

Abstract

Disclosed herein are a display substrate, a display panel, and a display apparatus, which can prevent excessive brightness attenuation at a large viewing angle. The display substrate comprises multiple laminated light-emitting devices. Each laminated light-emitting device comprises: a first electrode, a pixel definition layer comprising multiple pixel openings exposing corresponding first electrodes; a second electrode, which is disposed at a side of the first electrode distant from the substrate; and a light-emitting composite film layer, which is disposed between the first electrode and the second electrode. An edge of the pixel definition layer close to a pixel opening is provided with a climbing part, the slope angle of the climbing part being 15-45 degrees, and the slope angle being the included angle between a tangent line of the climbing part and a plane parallel to the substrate; in a direction perpendicular to the plane on which the display substrate is located, the height of the pixel definition layer is a first height, and the thickness of the light-emitting composite film layers in the pixel openings is a second height; the ratio of the first height to the second height of at least a portion of the laminated light-emitting devices is greater than or equal to 2.27.

Description

Display substrate, display panel and display device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and relates to a display substrate, a display panel and a display device. BACKGROUND

[0002] As a new generation of light-emitting display technology after liquid crystal display panels, organic light-emitting diodes (OLED) have advantages of wide viewing angle, high contrast, bright colors, flexible display and the like, and have been widely applied to various mobile phones, notebook computers and wearable devices.

[0003] In some applications, users sometimes need to view at a large viewing angle. However, there is a problem of too fast or too large luminance decay at a large viewing angle (for example, a viewing angle greater than 40 degrees) in current display panels, so that the luminance of the display panel is seriously darkened when the user changes from a normal viewing angle to a large viewing angle.

[0004] SUMMARY

[0005] The present disclosure provides a display substrate, a display panel and a display device, which can solve the problem of too fast or too large luminance decay at a large viewing angle (for example, a viewing angle greater than 40 degrees) in current display panels, so that the luminance of the display panel is seriously darkened when the user changes from a normal viewing angle to a large viewing angle.

[0006] In a first aspect, the present disclosure provides a display substrate, comprising a substrate, and a pixel definition layer and a plurality of light-emitting devices disposed on the substrate, the plurality of light-emitting devices comprising a plurality of stacked light-emitting devices, the stacked light-emitting device comprising:

[0007] a first electrode disposed on one side of the substrate, the pixel definition layer disposed on a side of the first electrode away from the substrate, the pixel definition layer comprising a plurality of pixel openings exposing corresponding first electrodes;

[0008] a second electrode disposed on a side of the first electrode away from the substrate;

[0009] a light-emitting composite film layer disposed between and in contact with the first electrode and the second electrode, the light-emitting composite film layer being disposed at least in the pixel openings;

[0010] wherein the pixel definition layer has a ramping portion near an edge of the pixel opening, the ramping portion having an angle of inclination of 15 degrees to 45 degrees, the angle of inclination being an angle between a tangent of the ramping portion and a plane parallel to the substrate;

[0011] The height of the pixel definition layer is a first height, and the thickness of the light-emitting recombination film layer in the pixel opening is a second height.

[0012] The ratio of the first height to the second height of the at least partial stacked light-emitting device is greater than or equal to 2.27.

[0013] In some embodiments, the ratio of the first height to the second height of the at least partial stacked light-emitting device is less than or equal to 10.5.

[0014] In some embodiments, the ratio of the slope angle to the first height is greater than or equal to 5, where the unit of the slope angle is degree and the unit of the first height is micrometer.

[0015] In some embodiments, the stacked light-emitting device is a two-layer tandem light-emitting device, and the light-emitting recombination film layer comprises:

[0016] a first light-emitting unit comprising a first hole transport layer and a first light-emitting layer, the first light-emitting layer being disposed on a side of the first hole transport layer away from the first electrode;

[0017] a charge generation layer disposed on a side of the first light-emitting unit away from the first electrode;

[0018] a second light-emitting unit disposed on a side of the charge generation layer away from the first light-emitting unit, the second light-emitting unit comprising a second hole transport layer and a second light-emitting layer, the second light-emitting layer being disposed on a side of the second hole transport layer away from the first electrode;

[0019] In the same stacked light-emitting device, the thickness of the first hole transport layer is greater than the thickness of the second hole transport layer.

[0020] In some embodiments, the plurality of light-emitting devices comprises a red light-emitting device, a green light-emitting device, and a blue light-emitting device, and each of the red light-emitting device, the green light-emitting device, and the blue light-emitting device is the stacked light-emitting device.

[0021] In some embodiments, the plurality of light-emitting devices satisfies at least one of the following conditions:

[0022] The second height of the red light-emitting device is in a range from 400 nanometers to 500 nanometers;

[0023] The second height of the green light-emitting device is in a range from 300 nanometers to 400 nanometers;

[0024] The second height of the blue light-emitting device is in a range from 200 nanometers to 300 nanometers.

[0025] In some embodiments, the first hole transport layer has a thickness greater than or equal to 800 nanometers; or / and

[0026] the second hole transport layer has a thickness greater than or equal to 440 nanometers.

[0027] In some embodiments, the first hole transport layer has a thickness less than or equal to 1500 nanometers; or / and

[0028] the second hole transport layer has a thickness less than or equal to 650 nanometers.

[0029] In some embodiments, the first light emitting unit further comprises a first auxiliary light emitting layer disposed between the first hole transport layer and the first light emitting layer, and the second light emitting unit further comprises a second auxiliary light emitting layer disposed between the second hole transport layer and the second light emitting layer.

[0030] The red light emitting device, the green light emitting device and the blue light emitting device have different first auxiliary light emitting layers and second auxiliary light emitting layers.

[0031] In some embodiments, the first auxiliary light emitting layer of the red light emitting device has a thickness greater than or equal to 800 nanometers, and the first auxiliary light emitting layer of the green light emitting device has a thickness greater than or equal to 430 nanometers; or / and

[0032] the first auxiliary light emitting layer of the blue light emitting device has a thickness greater than or equal to 65 nanometers.

[0033] In some embodiments, the first auxiliary light emitting layer of the red light emitting device has a thickness less than or equal to 1000 nanometers, and the first auxiliary light emitting layer of the green light emitting device has a thickness less than or equal to 550 nanometers; or / and

[0034] the first auxiliary light emitting layer of the blue light emitting device has a thickness less than or equal to 80 nanometers.

[0035] In some embodiments, the ratio of the first height to the second height of the blue light emitting device, the ratio of the first height to the second height of the green light emitting device, and the ratio of the first height to the second height of the red light emitting device decrease in turn.

[0036] In some embodiments, the slope angle close to the ramp of the blue light emitting device, the slope angle close to the ramp of the green light emitting device, and the slope angle close to the ramp of the red light emitting device increase in turn.

[0037] In a second aspect, the display panel is provided, comprising the display substrate in any of the above.

[0038] In a third aspect, the display device is provided, comprising the display substrate or the display panel in any of the above.

[0039] In the present disclosure, the ratio of the first height to the second height of the at least partially stacked light-emitting device is greater than or equal to 1. By matching the slope angle of the climbing portion with the height of the light-emitting composite film layer (the cavity length of the light-emitting device), the light-emitting efficiency of the stacked light-emitting device in a predetermined large viewing angle range can be increased, and the brightness attenuation of the stacked light-emitting device in a large viewing angle can be reduced. The light-emitting of the stacked light-emitting device is similar to Lambertian light-emitting. When the light rays emitted from the side are incident on the climbing portion of the pixel definition layer, the light rays emitted from the side are reflected, refracted, and then emitted from a large viewing angle to the human eye. By matching the slope angle of the climbing portion with the thickness of the light-emitting composite film layer (the cavity length of the light-emitting device), the first light rays can be emitted within a predetermined large viewing angle range after passing through the climbing portion of the pixel definition layer, the light loss is reduced, the light-emitting efficiency in a large viewing angle is improved, and the brightness attenuation in a large viewing angle is avoided. For example, the light-emitting efficiency in a viewing angle of 80 degrees or more is improved.

[0040] At the same time, in some other embodiments, in order not to greatly change the structure of the pixel definition layer and the like, while minimizing the brightness attenuation of the stacked light-emitting devices of different colors in a predetermined large viewing angle range, in some embodiments, the second height of the red light-emitting device is set to be in the range of 400 nanometers to 500 nanometers; in some embodiments, the second height of the green light-emitting device is set to be in the range of 300 nanometers to 400 nanometers; and in some embodiments, the second height of the blue light-emitting device is set to be in the range of 200 nanometers to 300 nanometers. BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is a first cross-sectional structure schematic diagram of a display substrate provided by an embodiment of the present disclosure;

[0042] FIG. 2 is a second cross-sectional structure schematic diagram of a display substrate provided by an embodiment of the present disclosure;

[0043] FIG. 3 is a first film layer stacking schematic diagram of a stacked light-emitting device provided by an embodiment of the present disclosure;

[0044] FIG. 4 is a second film layer stacking schematic diagram of a stacked light-emitting device provided by an embodiment of the present disclosure;

[0045] FIG. 5 is a chroma comparison schematic diagram of an embodiment and a comparative example provided by an embodiment of the present disclosure;

[0046] FIG. 6 is a first comparison schematic diagram of a stacked light-emitting device and a comparative example provided by an embodiment of the present disclosure;

[0047] FIG. 7 is a second comparison diagram of the stacked light-emitting device of the embodiment of the present disclosure and the comparative example. DETAILED DESCRIPTION

[0048] In order to better understand the technical solutions provided by the embodiments of the present disclosure, the technical solutions of the embodiments of the present disclosure will be described in detail below with the aid of the accompanying drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present disclosure and the specific embodiments are detailed descriptions of the technical solutions of the embodiments of the present disclosure, and not limitations of the technical solutions of the present disclosure. In the case of no conflict, the technical features in the embodiments of the present disclosure and the specific embodiments can be combined with each other.

[0049] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element. The term "two or more" includes two or more than two.

[0050] In some applications, the user sometimes needs to view at a large viewing angle. However, there is a problem of too fast or too large luminance decay at a large viewing angle in the current display panel, so that when the user changes from a normal viewing angle to a large viewing angle, the luminance of the display panel becomes dark seriously. For example, when the user views the display panel at a viewing angle greater than 40 degrees, the luminance of the display panel decays too fast, and the display panel has a significant darkening feeling, which reduces the viewing quality of the user. Meanwhile, the inventors have found that this problem is particularly serious in a display panel having a stacked light-emitting device.

[0051] Therefore, the present disclosure provides a display substrate, a display panel and a display device, which can solve the above-mentioned problems.

[0052] The present disclosure provides a display substrate, comprising a substrate, and a pixel definition layer and a plurality of light-emitting devices disposed on the substrate, wherein the plurality of light-emitting devices comprises a plurality of stacked light-emitting devices, and the stacked light-emitting device comprises:

[0053] a first electrode disposed on one side of the substrate, the pixel definition layer disposed on a side of the first electrode away from the substrate, the pixel definition layer comprising a plurality of pixel openings exposing corresponding first electrodes;

[0054] a second electrode disposed on a side of the first electrode away from the substrate;

[0055] a light-emitting composite film layer disposed between the first electrode and the second electrode and in contact with the first electrode and the second electrode, the light-emitting composite film layer being disposed at least within the pixel openings;

[0056] wherein the pixel definition layer has a ramping portion near an edge of the pixel opening, the ramping portion having an angle of inclination of 15 degrees to 45 degrees, the angle of inclination being an angle between a tangent of the ramping portion and a plane parallel to the substrate;

[0057] wherein, in a direction perpendicular to a plane in which the display substrate is located, a height of the pixel definition layer is a first height, and a thickness of the light-emitting composite film layer within the pixel opening is a second height;

[0058] wherein a ratio of the first height to the second height of at least part of the stacked light-emitting device is greater than or equal to 2.27.

[0059] The present disclosure also provides a display panel comprising the display substrate described above.

[0060] The present disclosure also provides a display device comprising the display panel described above.

[0061] Please refer to FIG. 1 and FIG. 2, FIG. 1 is a first cross-sectional structure schematic diagram of a display substrate provided by an embodiment of the present disclosure; FIG. 2 is a second cross-sectional structure schematic diagram of a display substrate provided by an embodiment of the present disclosure. FIG. 1 and FIG. 2 have the same structure, in order to more clearly illustrate the spirit of the present disclosure, the reference numerals in FIG. 1 and FIG. 2 are slightly different.

[0062] Referring to FIG. 3 and FIG. 4, FIG. 3 is a first film layer stack diagram of a stacked light-emitting device according to an embodiment of the present disclosure; and FIG. 4 is a second film layer stack diagram of a stacked light-emitting device according to an embodiment of the present disclosure. FIG. 3 illustrates a film layer stack diagram of a stacked light-emitting device, and FIG. 4 illustrates an overall film layer stack diagram of a red light-emitting device, a green light-emitting device, and a blue light-emitting device. In FIG. 4, EML1 R, EML2 R, Prime1 R, and Prime2 R represent a first light-emitting layer in the red light-emitting device, a second light-emitting layer in the red light-emitting device, a first auxiliary light-emitting layer in the red light-emitting device, and a second auxiliary light-emitting layer in the red light-emitting device, respectively. In FIG. 4, EML1 G, EML2 G, Prime1 G, and Prime2 G represent a first light-emitting layer in the green light-emitting device, a second light-emitting layer in the green light-emitting device, a first auxiliary light-emitting layer in the green light-emitting device, and a second auxiliary light-emitting layer in the green light-emitting device, respectively. In FIG. 4, EML1 B, EML2 B, Prime1 B, and Prime2 B represent a first light-emitting layer in the blue light-emitting device, a second light-emitting layer in the blue light-emitting device, a first auxiliary light-emitting layer in the blue light-emitting device, and a second auxiliary light-emitting layer in the blue light-emitting device, respectively.

[0063] The present disclosure provides a display substrate 100, which comprises a substrate 11, a pixel definition layer 14 and a plurality of light-emitting devices 20 disposed on the substrate 11, wherein the plurality of light-emitting devices 20 comprises a plurality of stacked light-emitting devices 20D, and each of the stacked light-emitting devices 20D comprises a first electrode 13, a second electrode 15, and a light-emitting composite film layer 201. The first electrode 13 is disposed on one side of the substrate 11, the pixel definition layer 14 is disposed on the side of the first electrode 13 away from the substrate 11, and the pixel definition layer 14 comprises a plurality of pixel openings 141 exposing corresponding first electrodes 13; the second electrode 15 is disposed on the side of the first electrode 13 away from the substrate 11; the light-emitting composite film layer 201 is disposed between the first electrode 13 and the second electrode 15 and contacts the first electrode 13 and the second electrode 15, and the light-emitting composite film layer 201 is disposed at least in the pixel openings 141; wherein the pixel definition layer 14 has a ramp portion 142 near the edge of the pixel opening 141, and the slope angle θ1 of the ramp portion 142 is 15 degrees to 45 degrees, and the slope angle θ1 is the included angle between the tangent of the ramp portion 142 and the plane parallel to the substrate 11 (FIG. 2 illustrates that the plane of the first electrode 13 is parallel to the plane of the substrate 11); wherein in the direction perpendicular to the plane in which the display substrate 100 is located, the height of the pixel definition layer 14 is a first height h1, and the thickness of the light-emitting composite film layer 201 in the pixel opening is a second height h2; wherein the ratio of the first height h1 to the second height h2 of at least part of the stacked light-emitting devices 20D is greater than or equal to 2.27.

[0064] For example, the first electrode layer is disposed on the substrate 11, and the first electrode layer includes a plurality of first electrodes 13. The pixel definition layer 14 is disposed on the first electrodes 13, and the pixel definition layer 14 includes a plurality of pixel openings 141, which expose surfaces of the corresponding first electrodes 13 away from the substrate 11. In the cross-sectional structure, the plurality of pixel openings 141 divide the pixel definition layer 14 into a plurality of pixel definition units, and each pixel definition unit is between two adjacent pixel openings 141.

[0065] For example, the film layer structure of the display substrate 10 can further include a plurality of thin film transistors, a plurality of wirings, and the like, which are disposed between the first electrodes 13 (the first electrode layer) and the substrate 11, the first electrodes 13 are electrically connected to the corresponding thin film transistors, and the light-emitting composite film layer 201 includes a plurality of sub-film layers, and at least part of the sub-film layers in the light-emitting composite film layer 201 emit light under the action of the electrical signal applied by the first electrode 13 and the second electrode 15.

[0066] For example, the plurality of light-emitting devices 20 includes a plurality of stacked light-emitting devices 20D. In some embodiments, part of the light-emitting devices 20 in the display substrate 100 are the stacked light-emitting devices 20D; in other embodiments, all of the light-emitting devices 20 in the display substrate 100 are the stacked light-emitting devices 20D.

[0067] For example, the light-emitting composite film layer 201 of the stacked light-emitting device 20D includes at least two layers of stacked light-emitting units and at least one stacked connection layer (charge generation layer), and the stacked connection layer is disposed between each two adjacent light-emitting units.

[0068] For example, one of the first electrode 13 and the second electrode 15 can be an anode, and the other can be a cathode. In the embodiments of the present disclosure, the first electrode 13 is taken as an example of the anode, and the second electrode 15 is taken as an example of the cathode.

[0069] For example, as shown in FIG. 2, the slope angle θ1 of the climbing portion 142 is 15 degrees to 45 degrees, and the slope angle θ1 is the included angle between the tangent of the climbing portion 142 and the plane parallel to the substrate 11.

[0070] For example, as shown in FIG. 2, in the direction perpendicular to the plane in which the display substrate 100 is located, or in the thickness direction of the display substrate 100, the height of the pixel definition layer 14 is a first height h1. FIG. 2 shows that the display substrate 100 further includes a planar layer 12 disposed between the first electrode and the substrate 11, and the pixel definition layer 14 is disposed on the planar layer 14, and the height of the pixel definition layer 14 on the planar layer 12 is the first height h1.

[0071] For example, as shown in FIG. 2, the thickness of the light-emitting composite film layer 201 in the pixel opening is a second height h2, that is, the distance between the surface of the first electrode 13 away from the substrate 11 and the surface of the second electrode 15 close to the substrate 11 is the second height h2. The second height h2 can also be understood as the cavity length of the light-emitting device 20.

[0072] For example, when the units of the first height h1 and the second height h2 are the same, for example, when the units of the first height h1 and the second height h2 are microns, the ratio of the first height h1 to the second height h2 of at least part of the stacked light-emitting device 20D is greater than or equal to 2.27.

[0073] For example, the part or surface of the pixel defining layer 14 (pixel defining unit) facing the pixel opening 141 connected thereto forms a ramping portion 142, the tangent of the ramping portion 142 and the plane parallel to the substrate 11 form an angle of θ1, and the angle of θ1 of the ramping portion 142 is greater than or equal to 15 degrees and less than or equal to 45 degrees.

[0074] For example, through the efforts of the inventors, it has been found that there is a problem of too fast or too large luminance decay at a large viewing angle (for example, a viewing angle greater than 40 degrees) in current display panels, especially in display panels with stacked light-emitting devices, so that when a user changes from a normal viewing angle to a large viewing angle, there is a problem of serious darkening of the luminance of the display panel. The reason is that the current arrangement of the pixel defining layer 14 and the light-emitting composite film layer 201 cannot be well matched, so that a large amount of light propagates horizontally or does not exit within a predetermined large viewing angle range, resulting in a large amount of light loss.

[0075] In the present disclosure, the ratio of the first height h1 to the second height h2 of at least part of the stacked light-emitting device 20D is greater than or equal to 2.27, and by matching the angle of θ1 of the ramping portion 142 with the height of the light-emitting composite film layer 201 (the cavity length of the light-emitting device), the light extraction efficiency of the stacked light-emitting device 20D within a predetermined large viewing angle range can be increased, and the luminance decay of the stacked light-emitting device 20D at a large viewing angle can be reduced. The light emitted by the stacked light-emitting device 20D is similar to Lambertian emission, and FIG. 2 shows that the light emitted from the side is the first light 101, and when the light of the first light 101 is incident on the ramping portion 142 of the pixel defining layer 14, the first light 101 is reflected, refracted, etc., and then the light is emitted from a large viewing angle to the human eye. By matching the angle of θ1 of the ramping portion 142 with the thickness of the light-emitting composite film layer 201 (the cavity length of the light-emitting device), the first light 101 can be emitted within a predetermined large viewing angle range after passing through the ramping portion 142 of the pixel defining layer 14, reducing light loss, improving the light extraction efficiency at a large viewing angle, and avoiding too fast or too large luminance decay at a large viewing angle, for example, improving the light extraction efficiency at a viewing angle of 40 degrees or more.

[0076] In some embodiments, the ratio of the first height h1 to the second height h2 of the at least partially stacked light-emitting device 20D is less than or equal to 10.5.

[0077] For example, the ratio of the first height h1 to the second height h2 of the at least partially stacked light-emitting device 20D is further limited to be less than or equal to 10.5, for example, while satisfying the ratio of the first height h1 to the second height h2 of the same stacked light-emitting device 20D is greater than or equal to 2.27 and less than or equal to 10.5.

[0078] For example, the inventors have found through analysis that when the ratio of the first height h1 to the second height h2 is too large, the pixel definition layer 14 will block the light rays in the predetermined large viewing angle range relative to the thickness of the light-emitting composite film layer 201 of the stacked light-emitting device 20D. The inventors have found through analysis that when the slope angle θ1 of the pixel definition layer 14 is too large, the luminance in the predetermined large viewing angle range will decay too quickly or too greatly.

[0079] For example, the ratio of the first height h1 to the second height h2 can be any value in the range of 2.27 to 10.5, for example, the ratio of the first height h1 to the second height h2 is any value in the range of 2.3, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10.

[0080] It should be noted that in some embodiments, the first height h1 is any value in the range of 1 micrometer, 1.2 micrometers, 1.5 micrometers, 1.7 micrometers.

[0081] In some embodiments, the slope angle θ1 is in degrees, the first height h1 is in micrometers, and the ratio of the slope angle θ1 to the first height h1 is greater than or equal to 5.

[0082] For example, the inventors have found through analysis that further limiting the ratio of the slope angle θ1 to the first height h1 can better improve the light extraction efficiency in the predetermined large viewing angle range and avoid the luminance in the predetermined large viewing angle range decaying too quickly or too greatly.

[0083] For example, the ratio of the slope angle θ1 to the first height h1 can be any value in the range of 5.5, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, etc.

[0084] For example, in some embodiments, the slope angle θ1 is in the range of 15 degrees to 45 degrees, and the first height h1 is in the range of 1 micrometer to 3 micrometers.

[0085] For example, in an embodiment, the slope angle θ1 is 25 degrees, and the first height h1 is 1.5 microns.

[0086] For example, in an embodiment, the slope angle θ1 is 25.6 degrees, the first height h1 is 1.5 microns, and the ratio of the slope angle θ1 to the first height h1 is 17.07, which achieves very good results in improving the light extraction efficiency in a preset large viewing angle range.

[0087] In some embodiments, the stacked light-emitting device 20D is a two-layer tandem light-emitting device 20, and the light-emitting composite film layer 201 includes a first light-emitting unit 21, a charge generation layer CGL, and a second light-emitting unit 22. The first light-emitting unit 21 includes a first hole transport layer HTL1 and a first light-emitting layer EML1, and the first light-emitting layer EML1 is disposed on the side of the first hole transport layer HTL1 away from the first electrode 13. The charge generation layer CGL is disposed on the side of the first light-emitting unit 21 away from the first electrode 13. The second light-emitting unit 22 is disposed on the side of the charge generation layer CGL away from the first light-emitting unit 21, and the second light-emitting unit 22 includes a second hole transport layer HTL2 and a second light-emitting layer EML2, and the second light-emitting layer EML2 is disposed on the side of the second hole transport layer HTL2 away from the first electrode 13. In the same stacked light-emitting device 20D, the thickness of the first hole transport layer HTL1 is greater than the thickness of the second hole transport layer HTL2.

[0088] For example, the charge generation layer CGL (stacked connection layer) is disposed between the first light-emitting unit 21 and the second light-emitting unit 22 (adjacent two light-emitting units) to achieve series connection. In some embodiments, the main function of the charge generation layer CGL is to provide electron carriers for the lower light-emitting unit and to provide hole carriers for the upper light-emitting unit.

[0089] For example, through the efforts of the inventors, it has been found that in order to achieve the cooperation and matching of the pixel limiting layer 14 and the light-emitting composite film layer 201 described above, it is necessary to increase the thickness (second height h2) of the light-emitting composite film layer 201 of the stacked light-emitting device 20D. Typically, the light-emitting composite film layer 201 in a light-emitting device includes a plurality of sub-film layers. In the thickness direction of the display substrate 100, the first hole transport layer HTL1 is farther away from the first light-emitting layer EML1, and the second hole transport layer HTL2 is farther away from the second light-emitting layer EML2. By increasing the first hole transport layer HTL1 to increase the thickness of the light-emitting composite film layer 201, the light-emitting efficiency of the first light-emitting layer EML1 can not be affected, or / and by increasing the second hole transport layer HTL2 to increase the thickness of the light-emitting composite film layer 201, the light-emitting efficiency of the second light-emitting layer EML2 can not be affected.

[0090] For example, through the efforts of the inventors, it is found that in a light-emitting device, the first electrode 13 is usually an anode that provides holes into the light-emitting composite film layer 201, and the second electrode 15 is a cathode that provides electrons into the light-emitting composite film layer 201. The mobility of holes is slow, and the mobility of electrons is fast. Excessive increase in the thickness of the second hole transport layer HTL2 will cause the overall mobility of the stacked light-emitting device 20D to decrease, and the light-emitting efficiency to decrease. Therefore, the first hole transport layer HTL1 can be increased in thickness, and the second hole transport layer HTL2 can be increased in thickness, while the overall mobility and light-emitting efficiency of the stacked light-emitting device 20D are less affected, and the original mobility and light-emitting efficiency of the stacked light-emitting device 20D are maintained.

[0091] In some embodiments, the plurality of light-emitting devices 20 includes a red light-emitting device 20R, a green light-emitting device 20G, and a blue light-emitting device 20B, and each of the red light-emitting device 20R, the green light-emitting device 20G, and the blue light-emitting device 20B is the stacked light-emitting device 20D of any one of the above.

[0092] In some other embodiments, at least one of the red light-emitting device 20R, the green light-emitting device 20G, and the blue light-emitting device 20B can be the stacked light-emitting device 20D of any one of the above.

[0093] In some embodiments, the plurality of light-emitting devices 20 at least satisfies one of the following conditions: the second height h2 of the red light-emitting device 20R is in a range of 400 nanometers to 500 nanometers; the second height h2 of the green light-emitting device 20G is in a range of 300 nanometers to 400 nanometers; and the second height h2 of the blue light-emitting device 20B is in a range of 200 nanometers to 300 nanometers.

[0094] For example, through the efforts of the inventors, it is found that in order to not greatly change the structure of the pixel definition layer 14 and the like, while at the same time minimizing the luminance decay of the stacked light-emitting devices 20D of different colors in a predetermined large viewing angle range, in some embodiments, the second height h2 of the red light-emitting device 20R is set to be in a range of 400 nanometers to 500 nanometers; in some embodiments, the second height h2 of the green light-emitting device 20G is set to be in a range of 300 nanometers to 400 nanometers; and in some embodiments, the second height h2 of the blue light-emitting device 20B is set to be in a range of 200 nanometers to 300 nanometers.

[0095] For example, in some stacked light-emitting devices 20D, the second height h2 of the red light-emitting device 20R can be any one of 400 nanometers, 420 nanometers, 440 nanometers, 460 nanometers, 480 nanometers, and 500 nanometers.

[0096] For example, in some stacked light-emitting devices 20D, the second height h2 of the green light-emitting device 20G can be any of 300 nm, 320 nm, 340 nm, 360 nm, 380 nm, 400 nm.

[0097] For example, in some stacked light-emitting devices 20D, the second height h2 of the blue light-emitting device 20B can be any of 200 nm, 220 nm, 240 nm, 260 nm, 280 nm, 300 nm.

[0098] In some embodiments, the first hole transport layer HTL1 has a thickness greater than or equal to 800 nm; or / and the second hole transport layer HTL2 has a thickness greater than or equal to 440 nm.

[0099] In some embodiments, the first hole transport layer HTL1 has a thickness less than or equal to 1500 nm; or / and the second hole transport layer HTL2 has a thickness less than or equal to 650 nm. By setting the thickness of the first hole transport layer HTL1 or / and the second hole transport layer HTL2 in this way, the pixel defining layer 14 and the light-emitting recombination film layer 201 are matched, thereby reducing the luminance decay in a preset large viewing angle range.

[0100] For example, by setting the thickness of the first hole transport layer HTL1 or / and the second hole transport layer HTL2 in this way, the pixel defining layer 14 and the light-emitting recombination film layer 201 are matched, thereby reducing the luminance decay in a preset large viewing angle range. At the same time, by setting the thickness of the first hole transport layer HTL1 or / and the second hole transport layer HTL2 in this way, the second height h2 of the red light-emitting device 20R can be in the range of 400 nm to 500 nm; the second height h2 of the green light-emitting device 20G can be in the range of 300 nm to 400 nm; and the second height h2 of the blue light-emitting device 20B can be in the range of 200 nm to 300 nm.

[0101] For example, in some embodiments, the first hole transport layer HTL1 has a thickness greater than or equal to 800 nm and less than or equal to 1500 nm. In some embodiments, the second hole transport layer HTL2 has a thickness greater than or equal to 440 nm and less than or equal to 650 nm.

[0102] For example, in some embodiments, the first hole transport layer HTL1 can have a thickness of any of 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm.

[0103] For example, in some embodiments, the second hole transport layer HTL2 can have a thickness of any of 450 nm, 500 nm, 550 nm, 600 nm.

[0104] In some embodiments, the first light emitting unit 21 further comprises a first auxiliary light emitting layer Prime1, the first auxiliary light emitting layer Prime1 is disposed between the first hole transport layer HTL1 and the first light emitting layer EML1, the second light emitting unit 22 further comprises a second auxiliary light emitting layer Prime2, the second auxiliary light emitting layer Prime2 is disposed between the second hole transport layer HTL2 and the second light emitting layer EML2. The red light emitting device 20R, the green light emitting device 20G and the blue light emitting device 20B have different first auxiliary light emitting layers Prime1 and second auxiliary light emitting layers Prime2. The thickness of the first auxiliary light emitting layer Prime1 of the red light emitting device 20R is greater than or equal to 800 nanometers, the thickness of the first auxiliary light emitting layer Prime1 of the green light emitting device 20G is greater than or equal to 430 nanometers; or / and the thickness of the first auxiliary light emitting layer Prime1 of the blue light emitting device 20B is greater than or equal to 65 nanometers.

[0105] For example, the first auxiliary light emitting layer Prime1 and the second auxiliary light emitting layer Prime2 are auxiliary light emitting layers, which can also be referred to as Prime layers, which can be used to lengthen the transmission path of holes. The material of the auxiliary light emitting layer can be the same as that of the hole transport layer, or can be different from that of the hole transport layer.

[0106] For example, through the efforts of the inventors, it is found that the thickness of the first auxiliary light emitting layer Prime1 and the second auxiliary light emitting layer Prime2 can be increased to some extent to increase the thickness of the light emitting composite film layer 201.

[0107] For example, the inventors found that the thickness of the first light emitting layer EML1 and the second light emitting layer EML2 of the red light emitting device 20R and the green light emitting device 20G is relatively thick, so that the light emitting efficiency of the red light emitting device 20R and the green light emitting device 20G is relatively insensitive to the thickness of the first auxiliary light emitting layer Prime1 and the second auxiliary light emitting layer Prime2, and therefore the thickness of the first light emitting layer EML1 and / or the second light emitting layer EML2 of the red light emitting device 20R and / or the green light emitting device 20G can be increased to a large extent, so that the pixel defining layer 14 cooperates with the light emitting composite film layer 201 of the red light emitting device 20R and the green light emitting device 20G, thereby reducing the luminance decay in the preset large viewing angle range, while maintaining the light emitting efficiency of the blue light emitting device 20B.

[0108] For example, the inventors have found that the thickness of the first and second light-emitting layers EML1 and EML2 of the blue light-emitting device 20B is very thin, so that the light-emitting efficiency of the blue light-emitting device 20B is very sensitive to the thickness of the first and second auxiliary light-emitting layers Prime1 and Prime2. Therefore, the thickness of the first and / or second light-emitting layers EML1 and EML2 of the blue light-emitting device 20B can be increased to a small extent, so that the pixel definition layer 14 cooperates with the light-emitting composite film layer 201 of the blue light-emitting device 20B, thereby reducing the luminance decay in the preset large viewing angle range while maintaining the light-emitting efficiency of the blue light-emitting device 20B.

[0109] For example, the inventors have found that the mobility of holes is slow, and the mobility of electrons is fast. Excessive increase in the thickness of the second auxiliary light-emitting layer Prime2 will cause the overall mobility of the stacked light-emitting device 20D to decrease, and the light-emitting efficiency to decrease. Therefore, the first auxiliary light-emitting layer Prime1 can be increased to a greater thickness, and the overall mobility and light-emitting efficiency of the stacked light-emitting device 20D are less affected, thereby maintaining the original mobility and light-emitting efficiency of the stacked light-emitting device 20D.

[0110] In some embodiments, the thickness of the first auxiliary light-emitting layer of the red light-emitting device 20R is less than or equal to 1000 nanometers, the thickness of the first auxiliary light-emitting layer of the green light-emitting device 20G is less than or equal to 550 nanometers; or / and the thickness of the first auxiliary light-emitting layer of the blue light-emitting device 20B is less than or equal to 80 nanometers.

[0111] For example, the inventors have found that the thickness of the first auxiliary light-emitting layer of the red light-emitting device 20R, the first auxiliary light-emitting layer of the green light-emitting device 20G, and the first auxiliary light-emitting layer of the blue light-emitting device 20B is too thick, which will cause the light-emitting efficiency of the stacked light-emitting device 20D to decrease. Therefore, setting an appropriate thickness of the first auxiliary light-emitting layer can ensure the light-emitting efficiency of the stacked light-emitting device 20D.

[0112] For example, in some embodiments, the thickness of the first auxiliary light-emitting layer Prime1 of the red light-emitting device 20R can be any one of 800 nanometers, 850 nanometers, 900 nanometers, 950 nanometers, and 1000 nanometers.

[0113] For example, in some embodiments, the thickness of the first auxiliary light-emitting layer Prime1 of the green light-emitting device 20G can be any one of 430 nanometers, 450 nanometers, 470 nanometers, 500 nanometers, 520 nanometers, and 550 nanometers.

[0114] For example, in some embodiments, the thickness of the first auxiliary light-emitting layer Prime1 of the blue light-emitting device 20B can be any one of 65 nm, 70 nm, 75 nm, 80 nm.

[0115] Further, the inventors have found through analysis that, when the thickness of the second auxiliary light-emitting layer Prime2 of the green light-emitting device 20G is greater than or equal to 150 nm and less than or equal to 190 nm, the thickness of the light-emitting recombination film layer 201 can be increased, so that the pixel definition layer 14 and the light-emitting recombination film layer 201 of the green light-emitting device 20G can be matched, thereby reducing the luminance decay in a preset large viewing angle range while maintaining the luminous efficiency of the green light-emitting device 20G.

[0116] In some embodiments, the ratio of the first height h1 to the second height h2 of the blue light-emitting device 20B, the ratio of the first height h1 to the second height h2 of the green light-emitting device 20G, and the ratio of the first height h1 to the second height h2 of the red light-emitting device 20R decrease in turn.

[0117] For example, in some stacked light-emitting devices 20D, the thicknesses of the light-emitting recombination film layers 201 of the red light-emitting device 20R, the green light-emitting device 20G, and the blue light-emitting device 20B decrease in turn. In order to match the thicknesses of the light-emitting recombination film layers 201 of the stacked light-emitting devices 20D of different colors, the ratio of the first height h1 to the second height h2 of the blue light-emitting device 20B, the ratio of the first height h1 to the second height h2 of the green light-emitting device 20G, and the ratio of the first height h1 to the second height h2 of the red light-emitting device 20R decrease in turn, which can better reduce the luminance decay in a preset large viewing angle range of the stacked light-emitting devices 20D of different colors.

[0118] In some embodiments, the slope angle θ1 of the ramp portion 142 near the blue light-emitting device 20B, the slope angle θ1 of the ramp portion 142 near the green light-emitting device 20G, and the slope angle θ1 of the ramp portion 142 near the red light-emitting device 20R increase in turn.

[0119] Referring to FIG. 5, a chroma comparison diagram of an embodiment provided by the present disclosure and a comparative example is shown.

[0120] For example, in some display devices or display terminals such as mobile phones, users prefer a display screen to be bluish (cold color), and the slope angle θ1 of the ramping portion 142 close to the blue light-emitting device 20B, the slope angle θ1 of the ramping portion 142 close to the green light-emitting device 20G, and the slope angle θ1 of the ramping portion 142 close to the red light-emitting device 20R are sequentially increased, so that the luminance attenuation of the blue light-emitting device 20B is improved the best in a preset large viewing angle range, the luminance attenuation of the green light-emitting device 20G is improved the second in the preset large viewing angle range, and the luminance attenuation of the red light-emitting device 20R is improved the weakest in the preset large viewing angle range, so that the display screen viewed by the user in the preset large viewing angle range also meets the user's cold color preference.

[0121] In FIG. 5, in the comparative example, the slope angle θ1 of the ramping portion 142 close to the blue light-emitting device 20B is equal to the slope angle θ1 of the ramping portion 142 close to the green light-emitting device 20G, and also equal to the slope angle θ1 of the ramping portion 142 close to the red light-emitting device 20R. In the embodiment, the slope angle θ1 of the ramping portion 142 close to the blue light-emitting device 20B, the slope angle θ1 of the ramping portion 142 close to the green light-emitting device 20G, and the slope angle θ1 of the ramping portion 142 close to the red light-emitting device 20R are sequentially increased.

[0122] As can be seen in FIG. 5, when the viewing angle changes from -75 degrees to 0 degrees, and then from 0 degrees to 75 degrees, the color coordinates of the white screen change, and compared with the comparative example, the color coordinate x and the color coordinate y of the embodiment are more biased to the small side, and the color coordinates of the embodiment are more biased to the cold color tone, and more in line with the user's preference for the display screen.

[0123] Referring to FIGS. 3 and 4, FIG. 3 illustrates that the stacked light-emitting device 20D includes, sequentially stacked on the first electrode 13: a hole injection layer HIL, a first hole transport layer HTL1, a first auxiliary light-emitting layer Prime1, a first light-emitting layer EML1, a first hole blocking layer HBL1, a first electron transport layer ETL1, a charge generation layer CGL, a second hole transport layer HTL2, a second auxiliary light-emitting layer Prime2, a second light-emitting layer EML2, a second hole blocking layer HBL2, a second electron transport layer ETL2, an electron injection layer EIL, and a second electrode 15. The structure of the stacked light-emitting device 20D is not limited to that shown in FIGS. 3 and 4, for example, the stacked light-emitting device 20D can not include the hole injection layer HIL or / and the electron injection layer EIL.

[0124] Referring to FIG. 4, the hole injection layer HIL, the first hole transport layer HTL1, the first hole blocking layer HBL1, the first electron transport layer ETL1, the charge generation layer CGL, the second hole transport layer HTL2, the second hole blocking layer HBL2, the second electron transport layer ETL2, and the electron injection layer EIL are common layers, i.e., the red light emitting device 20R, the green light emitting device 20G, and the blue light emitting device 20B share these film layers. The different color stacked light emitting device 20D has a different first auxiliary light emitting layer Prime1, a different first light emitting layer EML1, a different second auxiliary light emitting layer Prime2, and a different second light emitting layer EML2. FIGS. 3 and 4 illustrate that a light extraction layer CPL can be further provided on the side of the second electrode 15 away from the first electrode 11, and a LiF layer can be further provided on the side of the light extraction layer CPL away from the first electrode 11. However, the structure of the stacked light emitting device 20D is not limited thereto.

[0125] Referring to FIG. 4, the charge generation layer CGL can include a first charge generation layer P-CGL and a second charge generation layer N-CGL, the first charge generation layer P-CGL generates holes, and the second charge generation layer N-CGL generates electrons. The first charge generation layer P-CGL includes a P-type doped charge generation layer, and the second charge generation layer N-CGL includes an N-type doped charge generation layer. The P-type doped charge generation layer and the N-type doped charge generation layer can form a P / N junction structure, and can generate holes and electrons under the driving of the voltage loaded on the first electrode 11 and the second electrode 15 to excite the light emitting layers EML (the first light emitting layer EML1 and the second light emitting layer EML2) to emit light.

[0126] For example, the hole injection layer HIL can be a p-type dopant and a hole transport material doped with a strong electron-accepting system, such as hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane, and the like.

[0127] Exemplarily, the material of the first hole transport layer HTL1, the second hole transport layer HTL2, the first auxiliary light-emitting layer Prime1, the second auxiliary light-emitting layer Prime2, and the P-type doped charge generation layer can be arylamine and dimethylfluorene or carbazole materials with hole transport properties, such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (BAFLP), 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (DFLDPBi), 4,4'-di(9-carbazolyl) biphenyl (CBP), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA), and the like.

[0128] For example, the material of the first light-emitting layer EML1 and the second light-emitting layer EML2 can comprise one material or two or more mixed materials, and the light-emitting material is divided into a blue light-emitting material, a green light-emitting material, and a red light-emitting material. The blue light-emitting material is selected from pyrene derivatives, anthracene derivatives, fluorene derivatives, perylene derivatives, styrylamine derivatives, metal complexes, etc., for example, N1,N6-di([1,1'-biphenyl]-2-yl)-N1,N6-di([1,1'-biphenyl]-4-yl)pyrene-1,6-diamine, 9,10-di-(2-naphthyl)anthracene (ADN), 2-methyl-9,10-di-2-naphthylanthracene (MADN), 2,5,8,11-tetra-tert-butylperylene (TBPe), 4,4'-bis[4-(diphenylamino)styryl]biphenyl (BDAV Bi), 4,4'-bis[4-(dipara-tolylamino)styryl]biphenyl (DPAVBi), bis(4,6-difluorophenylpyridine-C2,N)picolinate iridium (FIrpic). The green light-emitting material is selected from coumarin dyes, quinacridone copper derivatives, polycyclic aromatic hydrocarbons, anthracene derivatives, carbazole derivatives, metal complexes, etc. For example, coumarin 6 (C-6), coumarin 545T (C-525T), quinacridone copper (QA), N,N'-dimethylquinacridone (DMQA), 5,12-diphenyl naphthacene (DPT), N10,N10'-diphenyl-N10,N10'-dibenzoanthracene-10,10'-diamine (abbreviation: BA-NPB), tris(8-hydroxyquinoline)aluminum (III) (abbreviation: Alq3), tris(2-phenylpyridine)iridium (Ir(ppy)3), bis(2-phenylpyridine)iridium (Ir(ppy)2(acac)). The red light-emitting material is selected from DCM series materials, metal complexes, etc., for example, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljuglavidin-9-enyl)-4H-pyran (DCJTB), bis(1-phenylisoquinoline)(acetylacetonate)iridium (III) (Ir(piq)2(acac)), octaethylporphyrin platinum (abbreviation: PtOEP), bis(2-(2'-benzothienyl)pyridine-N,C3')(acetylacetonate)iridium (abbreviation: Ir(btp)2(acac), etc.

[0129] For example, the material of the first hole blocking layer HBL1, the second hole blocking layer HBL2, the first electron transport layer ETL1, the second electron transport layer ETL2, and the second charge generation layer N-CGL can be an aromatic heterocyclic compound, such as a benzimidazole derivative, an imidazopyridine derivative, a benzimidazophenanthroline derivative, and the like; a pyrimidine derivative, a triazine derivative, and the like; a quinoline derivative, an isoquinoline derivative, a phenanthroline derivative, and the like; and the like. More specifically, the material of the first hole blocking layer HBL1, the second hole blocking layer HBL2, the first electron transport layer ETL1, the second electron transport layer ETL2, and the second charge generation layer N-CGL can be 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenyl)-1,2,4-triazole (TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (p-EtTAZ), bathophenanthroline (BPhen), 2,2',2"-terpyridine (BCP), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (BzOs), and the like.

[0130] For example, the material of the electron injection layer EIL can be an alkali metal or a metal, such as LiF, Yb, Mg, Ca, or a compound thereof, and the like.

[0131] For example, the material of the hole injection layer HIL can include F4TCNQ, which has the following molecular formula:

[0132] For example, the material of the hole transport layer HTL and the first charge generation layer P-CGL can include m-MTDATA, which has the following molecular formula:

[0133] For example, the material of the first auxiliary light-emitting layer Prime1 or / and the second auxiliary light-emitting layer Prime2 can include NPB, which has the following molecular formula:

[0134] For example, the material of the first hole blocking layer HBL1 or / and the second hole blocking layer HBL2 can include TPBi, which has the following molecular formula:

[0135] For example, the material of the electron transport layer ETL or / and the second charge generation layer N-CGL can include BCP, which has the following molecular formula:

[0136] For example, the blue light-emitting host material can include a material with a molecular formula as follows:

[0137] For example, the blue light-emitting guest material can include a material with a molecular formula as follows:

[0138] For example, the materials of the first hole transport layer HTL1, the second hole transport layer HTL2, the first auxiliary light-emitting layer Prime1, the second auxiliary light-emitting layer Prime2, and the P-type doped charge generation layer can be CBP, which has a molecular formula as follows:

[0139] For example, the materials of the first light-emitting layer EML1 and the second light-emitting layer EML2 can include Ir(ppy)3 or Ir(piq), which have molecular formulas as follows, respectively:

[0140] For example, the materials of the cover layer (light extraction layer CPL) can include NPB, which has a molecular formula as follows:

[0141] Referring to FIG. 6, FIG. 6 is a first comparison schematic diagram of the stacked light-emitting device and the comparative example according to the embodiments of the present disclosure; and FIG. 7 is a second comparison schematic diagram of the stacked light-emitting device and the comparative example according to the embodiments of the present disclosure.

[0142] As shown in FIG. 6 and FIG. 7, the sample under the embodiment condition meets the conditions of the various embodiments of the present disclosure, and the sample under the comparative example condition does not meet the conditions of the embodiments, for example, the sample under the comparative example condition does not meet the conditions that the second height h2 of the red light-emitting device 20R is in the range of 400 nm to 500 nm, the second height h2 of the green light-emitting device 20G is in the range of 300 nm to 400 nm, and the second height h2 of the blue light-emitting device 20B is in the range of 200 nm to 300 nm.

[0143] As shown in FIG. 6 and FIG. 7, the luminance decay of the red screen (R screen), the green screen (G screen), the blue screen (B screen), and the white screen (W screen) is compared.

[0144] As shown in FIG. 6, it is verified that the light-emitting efficiency of the embodiment is similar to that of the comparative example, which indicates that the light-emitting efficiency of the stacked light-emitting device 20 of the present disclosure is maintained.

[0145] As shown in FIG. 6, the test conditions are: in the range of 25 degrees to 75 degrees of view angle, the luminance is measured every 5 degrees interval, and the sum of the luminance of each measured view angle is calculated. Taking the sum of the luminance at large view angles of the comparative example as the reference (the sum of the luminance under each picture is normalized to 100% respectively), in each picture, the sum of the luminance of each large view angle of the embodiment is greater than 100% of the comparative example, which shows that the luminance decay of each view angle of each picture of the stacked light-emitting device 20 of the present disclosure is significantly improved.

[0146] As shown in FIG. 6, the fixed current density is 15 mA / cm 2 Under the test conditions, taking the operating voltage of the comparative example as the reference operating voltage (the operating voltage value of the comparative example is defined as 100%), taking the efficiency of the comparative example as the reference efficiency (the efficiency value of the comparative example is defined as 100%), and taking the lifetime of the comparative example as the reference lifetime (the lifetime value of the comparative example is defined as 100%, the lifetime represents: at 25°C, the light-emitting device or display panel is lit, and the time when the luminance decreases to 95% of the initial luminance), it can be found that the operating voltage, efficiency, and lifetime of each picture of the embodiment are close to 100%, for example, the lifetime of the red picture of the comparative example is 120 hours (normalized to 100%), and the lifetime of the red picture of the embodiment is 121 hours (normalized to 101%). FIG. 6 shows that compared with the comparative example, the operating voltage, efficiency, and lifetime of each picture of the embodiment are well maintained.

[0147] As shown in FIG. 7, FIG. 7(a), (b), (c), and (d) respectively show the red picture luminance decay curve (Red L-Decay curve), the green picture luminance decay curve (Green L-Decay curve), the blue picture luminance decay curve (Bule L-Decay curve), and the white picture luminance decay curve (White L-Decay curve). In FIG. 7, the horizontal coordinate represents the view angle, and the vertical coordinate represents the luminance (taking the normal view luminance normalized to 1 as the reference).

[0148] As shown in FIG. 7, in the red picture, the green picture, the blue picture, and the white picture, as the view angle increases (from 25 degrees to 75 degrees), the luminance decay degree of the sample under the conditions of the comparative example in each picture is greater (the luminance curve decreases more seriously), and the luminance decay degree of the sample under the conditions of the embodiment in each picture is well improved (the luminance curve decreases more gently), and the improvement effect is better when the view angle is greater than 40 degrees.

[0149] Combining FIG. 6 and FIG. 7, it can be known that the stacked light-emitting device 20D of the embodiment of the present disclosure has outstanding effect on improving the luminance decay at large view angles.

[0150] The display panel includes the display substrate 100 of any one of the above.

[0151] The display device includes the display substrate 100 or the display panel of any one of the above.

[0152] For example, the display device can be a mobile phone, a notebook computer, a television, or the like.

[0153] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0154] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

[0155] Although the preferred embodiments of the present disclosure have been described, those skilled in the art can make additional changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0156] Obviously, those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure also intends to include these modifications and variations.

Claims

1. A display substrate, wherein, The display substrate comprises a substrate, a pixel definition layer and a plurality of light emitting devices disposed on the substrate, the plurality of light emitting devices comprises a plurality of stacked light emitting devices, the stacked light emitting device comprises: a first electrode disposed on one side of the substrate, the pixel definition layer disposed on the side of the first electrode away from the substrate, the pixel definition layer comprising a plurality of pixel openings exposing the corresponding first electrode; a second electrode disposed on the side of the first electrode away from the substrate; a light emitting composite film layer disposed between the first electrode and the second electrode and contacting the first electrode and the second electrode, the light emitting composite film layer being disposed at least in the pixel opening; wherein the pixel definition layer has a ramping portion near the edge of the pixel opening, the slope angle of the ramping portion being 15 degrees to 45 degrees, the slope angle being the included angle between the tangent of the ramping portion and the plane parallel to the substrate; wherein in the direction perpendicular to the plane in which the display substrate is located, the height of the pixel definition layer is a first height, and the thickness of the light emitting composite film layer in the pixel opening is a second height; wherein the ratio of the first height to the second height of at least part of the stacked light emitting device is greater than or equal to 2.

27. 2.The display substrate of claim 1, wherein, The ratio of the first height to the second height of at least part of the stacked light emitting device is less than or equal to 10.

5. 3.The display substrate of claim 1, wherein, The ratio of the slope angle to the first height is greater than or equal to 5, the unit of the slope angle being degrees, and the unit of the first height being microns. 4.The display substrate according to any one of claims 1 to 3, wherein The stacked light emitting device is a two-layer series light emitting device, and the light emitting composite film layer comprises: a first light emitting unit comprising a first hole transport layer and a first light emitting layer, the first light emitting layer being disposed on the side of the first hole transport layer away from the first electrode; a charge generation layer disposed on the side of the first light emitting unit away from the first electrode; a second light emitting unit disposed on the side of the charge generation layer away from the first light emitting unit, the second light emitting unit comprising a second hole transport layer and a second light emitting layer, the second light emitting layer being disposed on the side of the second hole transport layer away from the first electrode; wherein in the same stacked light emitting device, the thickness of the first hole transport layer is greater than the thickness of the second hole transport layer. 5.The display substrate of claim 4, wherein, The plurality of light emitting devices comprises red light emitting devices, green light emitting devices and blue light emitting devices, and the red light emitting devices, the green light emitting devices and the blue light emitting devices are all stacked light emitting devices. 6.The display substrate of claim 5, wherein, The plurality of light emitting devices at least meets one of the following conditions: The second height of the red light emitting device is in the range of 400 nanometers to 500 nanometers; The second height of the green light emitting device is in the range of 300 nanometers to 400 nanometers; The second height of the blue light emitting device is in the range of 200 nanometers to 300 nanometers. 7.The display substrate of claim 5, wherein, The thickness of the first hole transport layer is greater than or equal to 800 nanometers; or / and The thickness of the second hole transport layer is greater than or equal to 440 nanometers. 8.The display substrate of claim 7, wherein, The thickness of the first hole transport layer is less than or equal to 1500 nanometers; or / and The thickness of the second hole transport layer is less than or equal to 650 nanometers. 9.The display substrate of claim 5, wherein, The first light-emitting unit further comprises a first auxiliary light-emitting layer disposed between the first hole transport layer and the first light-emitting layer, and the second light-emitting unit further comprises a second auxiliary light-emitting layer disposed between the second hole transport layer and the second light-emitting layer; The red light-emitting device, the green light-emitting device and the blue light-emitting device have different first auxiliary light-emitting layers and second auxiliary light-emitting layers; The thickness of the first auxiliary light-emitting layer of the red light-emitting device is greater than or equal to 800 nanometers, the thickness of the first auxiliary light-emitting layer of the green light-emitting device is greater than or equal to 430 nanometers; or / and The thickness of the first auxiliary light-emitting layer of the blue light-emitting device is greater than or equal to 65 nanometers. 10.The display substrate of claim 9, wherein, The thickness of the first auxiliary light-emitting layer of the red light-emitting device is less than or equal to 1000 nanometers, the thickness of the first auxiliary light-emitting layer of the green light-emitting device is less than or equal to 550 nanometers; or / and The thickness of the first auxiliary light-emitting layer of the blue light-emitting device is less than or equal to 80 nanometers. 11.The display substrate of claim 5, wherein, The ratio of the first height to the second height of the blue light-emitting device, the ratio of the first height to the second height of the green light-emitting device and the ratio of the first height to the second height of the red light-emitting device decrease in turn. 12.The display substrate of claim 5, wherein, The slope angle of the climbing part close to the blue light-emitting device, the slope angle of the climbing part close to the green light-emitting device and the slope angle of the climbing part close to the red light-emitting device increase in turn.

13. A display panel, wherein, The display substrate comprises the display substrate according to any one of claims 1 to 12.

14. A display device, wherein, The display panel comprises the display panel according to claim 13.

Images