Light-emitting substrate, display panel and display device

Abstract

A light-emitting substrate, a display panel and a display device are provided. The light-emitting substrate comprises: a base substrate; a planarization layer arranged on a side of the base substrate; and a light-emitting layer arranged on the side of the planarization layer away from the base substrate, wherein the planarization layer comprises N stacked sub-planarization layers, the sub-planarization layers each comprise a first surface on the side away from the base substrate, and the first surfaces of at least two sub-planarization layers comprise a plurality of concave surfaces, N being a positive integer greater than or equal to 2.

Description

Light-emitting substrate, display panel and display device TECHNICAL FIELD

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

[0002] At present, OLED (Organic Light-Emitting Diode) as a new type of light-emitting device has shown great application potential in the field of display and lighting, and has attracted strong attention in the industry. In the field of display, OLED has the advantages of self-luminous, fast response, wide viewing angle, high brightness and lightness, and is regarded as the next generation of display technology. However, due to waveguide effect and interface total reflection, the light-emitting device of OLED has low light extraction efficiency. Therefore, how to improve the light extraction efficiency of the light-emitting device of OLED is one of the important topics for the researchers in the field.

[0003] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those skilled in the art. SUMMARY

[0004] In one aspect, a light-emitting substrate is provided, comprising:

[0005] a substrate substrate;

[0006] a planar layer disposed on one side of the substrate substrate; and

[0007] a light-emitting layer disposed on a side of the planar layer away from the substrate substrate,

[0008] wherein the planar layer comprises N sub-planar layers stacked, the sub-planar layer comprises a first surface away from the substrate substrate, the first surface of at least two sub-planar layers comprises a plurality of concave surfaces, and N is a positive integer greater than or equal to 2.

[0009] According to some exemplary embodiments, the N sub-planar layers comprise an i-th sub-planar layer and an i+1-th sub-planar layer, the i+1-th sub-planar layer is located on a side of the i-th sub-planar layer away from the substrate substrate,

[0010] wherein the refractive index of the i+1-th sub-planar layer is greater than or equal to the refractive index of the i-th sub-planar layer, wherein i is a positive integer greater than or equal to 1 and less than or equal to N-1.

[0011] According to some exemplary embodiments, a distribution density of the plurality of concaves in the first surface of the i+1th sub-planar layer is less than or equal to a distribution density of the plurality of concaves in the first surface of the ith sub-planar layer.

[0012] According to some exemplary embodiments, in the first direction, a normal projection of the at least one concave in the first surface of the i+1th sub-planar layer on the substrate has an i+1th width, a normal projection of the at least one concave in the first surface of the ith sub-planar layer on the substrate has an ith width, and the i+1th width is greater than or equal to the ith width, wherein the first direction is parallel to a light-out surface of the light-emitting substrate.

[0013] According to some exemplary embodiments, a side wall angle of the at least one concave in the sub-planar layer is in a range of 30° to 40°.

[0014] According to some exemplary embodiments, the planar layer comprises a first sub-planar layer and a second sub-planar layer,

[0015] wherein a distribution density of the plurality of concaves in the first surface of the second sub-planar layer is equal to a distribution density of the plurality of concaves in the first surface of the first sub-planar layer; and

[0016] a second width of a normal projection of the at least one concave in the first surface of the second sub-planar layer on the substrate is equal to a first width of a normal projection of the at least one concave in the first surface of the first sub-planar layer on the substrate.

[0017] According to some exemplary embodiments, the planar layer further comprises a third sub-planar layer,

[0018] wherein a distribution density of the plurality of concaves in the first surface of the third sub-planar layer is equal to a distribution density of the plurality of concaves in the first surface of the second sub-planar layer; and

[0019] a third width of a normal projection of the at least one concave in the first surface of the third sub-planar layer on the substrate is equal to a second width of a normal projection of the at least one concave in the first surface of the second sub-planar layer on the substrate.

[0020] According to some exemplary embodiments, the planar layer comprises a first sub-planar layer and a second sub-planar layer,

[0021] wherein a distribution density of the plurality of concaves in the first surface of the second sub-planar layer is less than a distribution density of the plurality of concaves in the first surface of the first sub-planar layer; and

[0022] A second width of a normal projection of at least one concave surface in the first surface of the second sub-planar layer on the substrate is greater than a first width of a normal projection of at least one concave surface in the first surface of the first sub-planar layer on the substrate.

[0023] According to some exemplary embodiments, the planar layer further comprises a third sub-planar layer,

[0024] wherein a distribution density of a plurality of concave surfaces in the first surface of the third sub-planar layer is less than a distribution density of a plurality of concave surfaces in the first surface of the second sub-planar layer; and

[0025] A third width of a normal projection of at least one concave surface in the first surface of the third sub-planar layer on the substrate is greater than the second width of the normal projection of at least one concave surface in the first surface of the second sub-planar layer on the substrate.

[0026] According to some exemplary embodiments, a refractive index of the planar layer is in a range of 1.4 to 1.9.

[0027] According to some exemplary embodiments, a material of the planar layer comprises a combination of one or more of an epoxy resin, an acrylic, and a polyimide.

[0028] According to some exemplary embodiments, the ith sub-planar layer and the ith+1 sub-planar layer are in direct contact; and

[0029] The sub-planar layer further comprises a second surface proximate to a side of the substrate, the second surface of the ith+1 sub-planar layer comprises a plurality of convex surfaces, the plurality of convex surfaces in the second surface of the ith+1 sub-planar layer fill the plurality of concave surfaces in the first surface of the ith sub-planar layer.

[0030] According to some exemplary embodiments, the light-emitting layer comprises: a first electrode disposed on a side of the planar layer distal to the substrate; a light-emitting functional layer disposed on a side of the first electrode distal to the substrate; and a second electrode disposed on a side of the light-emitting functional layer distal to the substrate,

[0031] wherein the first electrode is disposed in conformance with a surface of the planar layer distal to the substrate; and

[0032] a surface of the first electrode proximate to the substrate comprises a plurality of convex surfaces; and / or,

[0033] a surface of the light-emitting functional layer proximate to the substrate comprises a plurality of convex surfaces; and / or,

[0034] a surface of the second electrode proximate to the substrate comprises a plurality of convex surfaces.

[0035] According to some exemplary embodiments, the light-emitting substrate further comprises: a driving circuit layer between the substrate and the planar layer; and a filter layer between the driving circuit layer and the planar layer.

[0036] In another aspect, there is provided a display panel, wherein the display panel comprises the light-emitting substrate according to any one of the preceding aspects.

[0037] In yet another aspect, there is provided a display device, wherein the display device comprises the light-emitting substrate according to any one of the preceding aspects or the display panel according to the preceding aspect. BRIEF DESCRIPTION OF DRAWINGS

[0038] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0039] FIG. 1 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0040] FIG. 2 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0041] FIG. 3 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0042] FIG. 4 is a partial enlarged view of the area of the dashed line box S1 in FIG. 3;

[0043] FIG. 5 is a structural schematic diagram of a light-emitting device according to exemplary embodiments of the present disclosure;

[0044] FIG. 6 is a schematic diagram of the relationship between the spacing distance of part of the film layers in the light-emitting functional layer and the second electrode and the light-emitting effect according to exemplary embodiments of the present disclosure;

[0045] FIG. 7 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0046] FIG. 8 is a structural schematic diagram of a planar layer according to exemplary embodiments of the present disclosure;

[0047] FIG. 9 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0048] FIG. 10 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0049] FIG. 11 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0050] FIG. 12 is a structural schematic diagram of a light-emitting substrate according to exemplary embodiments of the present disclosure;

[0051] FIG. 13 is a structural block diagram of a display panel according to an embodiment of the disclosure; and

[0052] FIG. 14 is a structural block diagram of a display device according to an embodiment of the disclosure.

[0053] It is noted that, for the sake of clarity, the size of layers, structures or regions can be exaggerated or reduced in the drawings used to describe embodiments of the present disclosure, i.e., the drawings are not drawn to scale. DETAILED DESCRIPTION

[0054] For the purpose of the present disclosure, the technical solutions and advantages of embodiments of the present disclosure will be more clearly described below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present disclosure.

[0055] It should be noted that, in the drawings, the size and relative size of the elements can be exaggerated for clarity and / or descriptive purposes. Thus, the size and relative size of the various elements in the drawings should not be construed as limiting. In the description and drawings, identical or similar reference numerals indicate identical or similar components.

[0056] Unless otherwise defined, technical terms or scientific terms used in the present disclosure should be understood as having the common meaning understood by those of ordinary skill in the art. The terms "first", "second" and similar words used in the present disclosure do not indicate any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, and do not exclude other elements or objects.

[0057] In this document, unless otherwise specifically stated, directional terms such as "upper", "lower", "left", "right", "inner", "outer" and the like are used to indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure, and do not indicate or imply that the devices, elements or components referred to must have a particular orientation, be constructed or operated in a particular orientation. It is understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms cannot be understood as a limitation on the present disclosure.

[0058] In this document, the terms“substantial,”“approximately,”“about,” and other similar terms are used as terms of approximation and not as terms of degree, and they are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. Considering, for example, process variations, measurement limitations, and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system),“about” or“approximately,” as used herein includes the stated value and means a range of values determined to be acceptable by those of ordinary skill in the art to the particular value. For example,“about” can mean within one or more standard deviations, or within ±10% or ±5% of the stated value.

[0059] In this document, directional expressions such as“first direction,”“second direction” are used to describe different directions of the light-emitting substrate or the display panel, for example, the light-emitting surface direction of the light-emitting substrate or the normal direction perpendicular to the light-emitting surface. It should be understood that such expressions are only exemplary descriptions and are not limitations of the present disclosure.

[0060] OLED light-emitting devices have great application potential in the fields of display and lighting as a new type of light-emitting device, and have attracted strong attention from the academic and industrial circles. In the field of display, OLED display devices have the advantages of self-emission, fast response, wide viewing angle, high brightness, bright color, lightness, and the like, and are widely used in mobile phones, computers, televisions, and micro display fields.

[0061] However, OLED light-emitting devices have low light-emitting efficiency due to material limitations and the influence of light-emitting modes. The influence of the light-emitting mode mainly includes internal and external waveguide effects and interface total reflection. At present, the light-emitting efficiency is mainly improved by reducing non-emitting modes and waveguide effects, reducing total reflection, and the like. For example, a non-flat surface can be formed by using a micro lens array to suppress interface total reflection, and the micro lens can also increase the light-emitting surface and realize edge light convergence, thereby improving the light-emitting efficiency and improving the light-emitting brightness.

[0062] In the related art, a top-emitting device mainly forms a micro lens on a packaging layer through thermal reflow. For example, the light-emitting efficiency is improved by designing an external extraction structure (EES) and a microlens array (MLA) filled inside the pixel.

[0063] WOLED (White Organic Light-Emitting Diode, white organic light-emitting diode) has a longer service life and higher luminous efficiency compared with ordinary OLED devices, and therefore, has been more widely used. The WOLED usually adopts a bottom emission design. There is a certain process difficulty in how to form an MLA in a bottom emission WOLED light-emitting substrate. A certain arc-shaped pit is usually formed on the flat layer in the pixel, but the current MLA structure has limited improvement range for the bottom emission WOLED light-emitting substrate, resulting in still low light extraction efficiency.

[0064] It should be noted that bottom emission is a light-emitting mode in OLED display technology, which means that light is emitted from the anode of the device. In this structure, the structure of the device from top to bottom usually includes an opaque metal cathode, an organic functional layer, and a transparent anode. Since the light is emitted from the anode, it is called bottom emission.

[0065] Exemplary embodiments of the present disclosure provide a light-emitting substrate. Specifically, the light-emitting substrate includes a substrate substrate, a flat layer disposed on one side of the substrate substrate, and a light-emitting layer disposed on a side of the flat layer away from the substrate substrate. The flat layer includes N sub-flat layers stacked, the sub-flat layer includes a first surface on a side away from the substrate substrate, the first surface of at least two sub-flat layers includes a plurality of concave surfaces, and N is a positive integer greater than or equal to 2.

[0066] By designing the flat layer to include a plurality of sub-flat layers, at least two of the plurality of sub-flat layers include a concave surface design, the total number of concave surfaces in the flat layer can be increased. When the light emitted by the light-emitting layer passes through the flat layer and is emitted to the outside, the increased distribution density of the concave surfaces can better suppress the loss of light at the film layer interface, reduce the probability of occurrence of the interface total reflection phenomenon, and is conducive to improving the light extraction efficiency of the OLED light-emitting substrate, reducing power consumption, and improving the brightness of the light-emitting substrate.

[0067] FIG. 1 is a structural schematic diagram of a light-emitting substrate according to an exemplary embodiment of the present disclosure, and FIG. 2 is a structural schematic diagram of a light-emitting substrate according to an exemplary embodiment of the present disclosure.

[0068] Exemplarily, the embodiments of the present disclosure provide a light-emitting substrate 100. The light-emitting substrate 100 can include an OLED light-emitting device, for example, one or more of a red OLED light-emitting device, a green OLED light-emitting device, a blue OLED light-emitting device, and a white OLED light-emitting device.

[0069] Exemplarily, referring to FIG. 1, the light-emitting substrate 100 can include a first electrode 51, a light-emitting functional layer 52, and a second electrode 53. For example, the first electrode 51 can be an anode, and the second electrode 53 can be a cathode. When a voltage is applied on the first electrode 51 and the second electrode 53, the light-emitting functional layer 52 can be excited to emit light, which is then emitted outwards.

[0070] Exemplarily, the light-emitting substrate 100 can further include a substrate 50. The substrate 50 can be located on a side of the first electrode 51 away from the second electrode 53. For example, the substrate 50 can include a glass substrate. The glass substrate has high transparency, which is conducive to the transmission of visible light through the substrate and emission outwards.

[0071] Exemplarily, the direction of the light emitted by the light-emitting substrate 100 is related to the transparency of the first electrode 51 and the second electrode 53. For example, the first electrode 51 has high transparency, and the second electrode 53 is opaque. In this case, the light emitted by the light-emitting functional layer 52 is mainly emitted outwards through the side of the first electrode 51.

[0072] Exemplarily, the first electrode 51 can include a transparent conductive material, such as indium tin oxide (ITO). The second electrode 53 can include an opaque conductive material, such as a thick conductive metal layer, for example, a metal or metal alloy such as aluminum, silver, magnesium / silver, etc.

[0073] Due to the difference in refractive index of the materials of the multiple film layers in the light-emitting substrate, the propagation path of the light changes when the light propagates at the interface of different film layers. Referring to FIG. 1, when the light is incident from a flat surface with a high refractive index to a flat surface with a low refractive index, for example, from a glass surface to an air interface, the light within a certain range of incident angles will be totally reflected at the interface, which results in the inability to emit outwards, thus reducing the light-emitting efficiency of the light-emitting substrate. For example, the light in the incident light with an angle greater than θ1 with respect to the normal line L1 of the light-emitting surface will be totally reflected at the interface between the glass substrate and the air, which cannot be emitted outwards, resulting in low light-emitting efficiency of the light-emitting substrate.

[0074] Exemplarily, referring to FIG. 2, in order to reduce the probability of interface total reflection of the emitted light, a plurality of lenses 40 can be designed on a side of the substrate 50 away from the light-emitting functional layer 52. The plurality of lenses 40 can be arranged in an array. The light emitted by the light-emitting functional layer 52 can enter the lenses 40 after passing through the substrate 50, and then be emitted outwards by the lenses 40 into the air. For example, part of the light in the incident light with an angle greater than θ1 with respect to the normal line L1 of the light-emitting surface can be emitted outwards from the convex arc surface of the lens 40 after refraction by the lens 40. By adjusting the refractive index and the curvature angle of the lens 40, the probability of total reflection of the emitted light at the interface can be reduced, thereby improving the light-emitting efficiency of the light-emitting substrate 100.

[0075] FIG. 3 is a structural schematic diagram of a light-emitting substrate according to an example embodiment of the present disclosure, FIG. 4 is a partial enlarged view of the area of the dashed box S1 in FIG. 3, FIG. 5 is a structural schematic diagram of a light-emitting device according to an example embodiment of the present disclosure, and FIG. 6 is a schematic diagram of the relationship between the spacing distance of a part of a film layer and a second electrode in a light-emitting functional layer and the light-emitting effect according to an example embodiment of the present disclosure.

[0076] For example, in the embodiments of the present disclosure, the light-emitting substrate 100 can include a WOLED light-emitting substrate. The WOLED light-emitting substrate generally adopts a bottom emission design.

[0077] In the WOLED-related preparation, in combination with reference to FIGS. 3 and 4, after the preparation of the driving circuit layer 2 on the substrate substrate 1 is completed, a planar layer 4 can be formed on the side of the driving circuit layer 2 away from the substrate substrate 1. By forming a plurality of concave structures on the side of the planar layer 4 away from the substrate substrate 1, a microlens array structure can be obtained. Further, a light-emitting layer 5 is arranged on the side of the planar layer 4 with the microlens array structure. For example, the light-emitting layer 5 can include a first electrode 51, a light-emitting functional layer 52, and a second electrode 53 arranged in sequence away from the planar layer 4.

[0078] For example, the light-emitting substrate 100 can further include a light filtering layer 3 between the planar layer 4 and the driving circuit layer 2. For example, the light filtering layer 3 can include a plurality of color filters, and the white light emitted by the WOLED light-emitting device can form a plurality of colors of light, such as red light, green light, and blue light, after passing through the light filtering layer 3, thereby realizing color display.

[0079] For example, the light filtering layer 3 can further include a black matrix layer, and the black matrix layer can define a plurality of pixel openings.

[0080] In the embodiments of the present disclosure, by arranging the microlens array structure on the side of the planar layer 4 close to the light-emitting layer 5, the probability of the total reflection phenomenon of the light emitted by the light-emitting layer in the light-emitting substrate can be reduced, thereby improving the light extraction efficiency of the light-emitting substrate.

[0081] However, since the first electrode 51, the light-emitting functional layer 52 and the second electrode 53 are arranged on the side of the planar layer 4 having the microlens array structure, the topography of the stacked structure of the first electrode 51, the light-emitting functional layer 52 and the second electrode 53 will be affected by the microlens array structure, i.e. having a plurality of convex regions and a plurality of concave regions. As shown in FIG. 4, in the light-emitting layer 5 of the stacked structure, the first electrode 51 and the second electrode 53 are oppositely arranged, and the light-emitting functional layer 52 is located between the first electrode 51 and the second electrode 53. The thickness of the light-emitting functional layer 52 at different positions of the concave regions is different, for example, as shown by d1, d2 and d3 in FIG. 4, the thickness of the light-emitting functional layer 52 at different positions is obviously different. For example, the light-emitting functional layer 52 can include a main light-emitting region I and an auxiliary light-emitting region II. The thickness of the light-emitting functional layer of the main light-emitting region I located on the side wall of the concave region is smaller than the thickness of the light-emitting functional layer of the auxiliary light-emitting region II located at the bottom of the concave region. For example, d3 is smaller than d1. The auxiliary light-emitting region II also includes a part of the light-emitting layer located in the convex region. The thickness of the light-emitting functional layer of the main light-emitting region I located on the side wall of the concave region is smaller than the thickness of the light-emitting functional layer of the auxiliary light-emitting region II located in the convex region. For example, d3 is smaller than d2.

[0082] It can be understood that due to the difference in the thickness of the light-emitting functional layer 52 of the main light-emitting region I and the thickness of the light-emitting functional layer 52 of the auxiliary light-emitting region II, the difference in the thickness of the light-emitting functional layer 52 will affect the brightness and color of the light emission. For example, FIG. 5 shows a structure of a WOLED light-emitting device, which includes a first electrode 51, a light-emitting functional layer 52 and a second electrode 53. The light-emitting functional layer 52 includes a first sub-light-emitting layer 521, a first charge generation layer 522, a second sub-light-emitting layer 523, a second charge generation layer 524 and a third sub-light-emitting layer 525. For example, the first sub-light-emitting layer 521 includes a blue light-emitting layer, the second sub-light-emitting layer 523 includes a yellow-green light-emitting layer 5231 and a red light-emitting layer 5232, and the third sub-light-emitting layer 525 includes a blue light-emitting layer. The interval distance between the sub-light-emitting layers of different colors and the second electrode 53 will affect the light-emitting efficiency of the sub-light-emitting layer and the wavelength (or color) of the emitted light. For example, the interval distance between the first sub-light-emitting layer 521 and the second electrode 53 is H1, the interval distance between the second sub-light-emitting layer 523 and the second electrode 53 is H2, and the interval distance between the third sub-light-emitting layer 525 and the second electrode 53 is H3. Due to the difference in the thickness of the light-emitting functional layer 52 of the main light-emitting region I and the thickness of the light-emitting functional layer 52 of the auxiliary light-emitting region II, the values of H1, H2 and H3 in different regions will be different.

[0083] Table 1 shows the interval distance of different sub-light-emitting layers from the second electrode in different regions

[0084] As can be seen from Table 1, the multiple sub-light-emitting layers have obvious thickness differences in the main light-emitting area and the auxiliary light-emitting area. The greater the side wall angle of the lens structure, the more significant the thickness difference of the multiple sub-light-emitting layers in the main light-emitting area and the auxiliary light-emitting area.

[0085] It should be noted that the side wall angle of the lens structure refers to the angle between the tangent of the arc surface of the lens and the horizontal plane.

[0086] For example, FIG. 6 shows the relationship between the light-emitting efficiency and wavelength of different sub-light-emitting layers and the interval distance between the sub-light-emitting layer and the second electrode 53. The abscissa X1 represents the wavelength of the light emitted by the sub-light-emitting layer, the ordinate Y1 represents the interval distance between the sub-light-emitting layer and the second electrode, and different color depths represent different light intensities. The light intensity of the area with darker color is greater than that of the area with lighter color. As the interval distance between the sub-light-emitting layer and the second electrode 53 changes, the light-emitting efficiency of the sub-light-emitting layer also changes significantly. For example, for the yellow-green light-emitting layer YG2, the interval distance between the yellow-green light-emitting layer in the S2 area and the second electrode is smaller than that between the yellow-green light-emitting layer in the S3 area, which causes the light-emitting efficiency of the yellow-green light-emitting layer in the S2 area to be higher than that of the yellow-green light-emitting layer in the S3 area.

[0087] The microlens array in the flat layer causes the thickness of the light-emitting functional layer 52 to be different in different areas, and the thickness difference of the light-emitting functional layer 52 causes the brightness and color of light emitted in different areas to be different, affecting the display effect. In order to reduce the thickness difference between different areas, the lens curvature / slope of the microlens array is generally reduced, and the inner diameter is increased, for example, to ensure that the side wall angle of most of the lens structure is between 20° and 45°, thereby reducing the thickness difference between different areas.

[0088] The inventors have found that in a light-emitting substrate using a flat layer containing a single-layer microlens array, increasing the inner diameter of the lens and reducing the lens curvature / slope can cause the lens distribution density in the flat layer to decrease significantly, thereby reducing the light extraction effect of the microlens array. That is, the flat layer containing a single-layer microlens array still has insufficient effect on improving the light extraction efficiency of the light-emitting substrate, and the light extraction efficiency of the light-emitting substrate still needs to be further improved.

[0089] In an embodiment of the present disclosure, the flat layer can include multiple sub-flat layers, and the surface of each sub-flat layer close to the substrate can include a microlens array structure, thereby increasing the overall lens distribution density in the flat layer and improving the light extraction efficiency. On the other hand, the side wall angle of the lens on the surface of the sub-flat layer close to the light-emitting layer can be set to be smaller, which can reduce the thickness difference of the light-emitting functional layer in different areas and be beneficial to improving the light-emitting effect.

[0090] FIG. 7 is a structural schematic diagram of a light-emitting substrate according to an example embodiment of the present disclosure, and FIG. 8 is a structural schematic diagram of a planar layer according to an example embodiment of the present disclosure.

[0091] For example, in an embodiment of the present disclosure, referring to FIG. 7, a light-emitting substrate 100 is provided. The light-emitting substrate 100 can include a substrate substrate 1, a planar layer 4 disposed on one side of the substrate substrate 1, and a light-emitting layer 5 disposed on a side of the planar layer 4 away from the substrate substrate 1.

[0092] For example, the light-emitting substrate 100 can further include a driving circuit layer 2 between the substrate substrate 1 and the planar layer 4, and a filter layer 3 between the driving circuit layer 2 and the planar layer 4.

[0093] For example, the planar layer 4 can include N sub-planar layers stacked, the sub-planar layers including a first surface on a side away from the substrate substrate 1, the first surfaces of at least two of the sub-planar layers including a plurality of concave surfaces, and N being a positive integer greater than or equal to 2. For example, the planar layer 4 can include 2 sub-planar layers stacked, the first surfaces of the 2 sub-planar layers on a side away from the substrate substrate 1 including a plurality of concave surfaces. For another example, the planar layer 4 can include 3 sub-planar layers stacked, the first surfaces of the 3 sub-planar layers on a side away from the substrate substrate 1 including a plurality of concave surfaces. In some embodiments, the planar layer 4 can further include more layers of sub-planar layers stacked, such as 4 layers, 5 layers, or more, which are not limited in the embodiments of the present disclosure.

[0094] Through such a design, the overall lens distribution density in the planar layer can be increased, which is beneficial to improve the light-emitting efficiency of the light-emitting substrate.

[0095] For example, referring to FIGS. 4 and 7, the light-emitting layer 5 can include a first electrode 51 disposed on a side of the planar layer 4 away from the substrate substrate 1, a light-emitting functional layer 52 disposed on a side of the first electrode 51 away from the substrate substrate 1, and a second electrode 53 disposed on a side of the light-emitting functional layer 52 away from the substrate substrate 1. The first electrode 51 is disposed in close contact with the surface 400 of the planar layer 4 on a side away from the substrate substrate 1.

[0096] For example, the surface of the first electrode 51 close to the substrate substrate 1 includes a plurality of convex surfaces, and / or the surface of the light-emitting functional layer 52 close to the substrate substrate 1 includes a plurality of convex surfaces, and / or the surface of the second electrode 53 close to the substrate substrate 1 includes a plurality of convex surfaces. That is, the plurality of film layers in the light-emitting layer 5 can be formed in a shape following the planar layer 4, so that the plurality of film layers in the light-emitting layer 5 close to the surface of the substrate substrate 1 include a plurality of convex surfaces. The spacing distance between the plurality of film layers in the light-emitting layer 5 and the second electrode is affected by the topography of the surface 400 of the planar layer 4 close to the light-emitting layer 5.

[0097] In order to improve the consistency of the film thickness of different regions in the light-emitting layer and improve the light-emitting uniformity, the side wall angle of the lens structure in the planar layer is designed in an embodiment of the present disclosure.

[0098] For example, the side wall angle of the concave surface of the sub-planar layer in direct contact with the light-emitting layer 5 is in the range of 30° to 40°.

[0099] For example, the side wall angle of the concave surface of the sub-planar layer in direct contact with the light-emitting layer 5 is in the range of 30° to 40°.

[0100] Through such a design, the thickness difference of the light-emitting functional layer in different regions can be reduced, which is conducive to improving the light-emitting uniformity and improving the display effect.

[0101] For example, referring to FIGS. 7 and 8, the N sub-planar layers can include an i-th sub-planar layer and an i+1-th sub-planar layer. The i+1-th sub-planar layer is located on the side of the i-th sub-planar layer away from the substrate. The refractive index of the i+1-th sub-planar layer is greater than or equal to the refractive index of the i-th sub-planar layer, where i is a positive integer greater than or equal to 1 and less than or equal to N-1.

[0102] Through such a design, the multiple sub-planar layers in the planar layer can form a gradually changing refractive index gradient. The light emitted by the light-emitting layer will be refracted when passing through the interface of the multiple sub-planar layers in the planar layer. The design of the gradually changing refractive index can avoid the refractive index difference between adjacent two film layer interfaces being too large, which is conducive to reducing the probability of total reflection phenomenon, thereby improving the light extraction efficiency of the light-emitting substrate.

[0103] For example, the refractive index of the planar layer is in the range of 1.4 to 1.9. For example, the refractive index of the i+1-th sub-planar layer is in the range of 1.7 to 1.9, and the refractive index of the i-th sub-planar layer is in the range of 1.4 to 1.7. For another example, the refractive index of the i+2-th sub-planar layer is in the range of 1.8 to 1.9, the refractive index of the i+1-th sub-planar layer is in the range of 1.6 to 1.8, and the refractive index of the i-th sub-planar layer is in the range of 1.4 to 1.6.

[0104] For example, the material of the planar layer can include a transparent organic material. For example, the material of the planar layer can include a combination of one or more of epoxy resin, acrylic, and polyimide.

[0105] For example, the multiple concave structures in the planar layer can be formed by an imprinting technology.

[0106] For example, the i-th sub-planarization layer and the (i+1)-th sub-planarization layer are in direct contact. That is, the surface of the (i+1)-th sub-planarization layer near the i-th sub-planarization layer can fill multiple concave surfaces in the surface of the i-th sub-planarization layer near the (i+1)-th sub-planarization layer. For example, referring to FIG8, the sub-planarization layer also includes a second surface near the substrate side. The second surface 42 of the (i+1)-th sub-planarization layer i+1 Including multiple convex surfaces, the second surface 42 of the (i+1)th sub-planar layer i+1 Multiple convex surfaces fill the first surface 41 of the i-th sub-flat layer i Multiple concave surfaces in it.

[0107] With this design, multiple stacked sub-planar layers can be arranged adjacent to each other without the need for additional transition layers in between, simplifying the fabrication process and reducing costs.

[0108] In an exemplary embodiment of this disclosure, the first surface 41 of the (i+1)th sub-planarization layer i+1 Multiple concave surfaces 40 i+1 The distribution density is less than or equal to the multiple concave surfaces 40 in the first surface 41i of the i-th sub-flat layer. i The distribution density. That is, in the same region, the first surface 41 of the (i+1)th sub-flat layer. i+1 Multiple concave surfaces 40 i+1 The number of concave surfaces 40 in the first surface 41i of the i-th sub-flat layer is less than or equal to the number of concave surfaces 40 in the first surface 41i of the i-th sub-flat layer. i The quantity.

[0109] It should be noted that the "distribution density" of concave surfaces in the embodiments of this disclosure refers to the number of concave surfaces per unit area. For example, the distribution density of multiple concave surfaces may include 3 concave surfaces / cm². 2 .

[0110] In an exemplary embodiment of this disclosure, in the first direction X, the first surface 41 of the (i+1)th sub-planarization layer i+1 At least one concave surface 40 i+1 The orthographic projection on the substrate has a width D of the (i+1)th degree. i+1 The first surface 41 of the i-th sub-flat layer i At least one concave surface 40 i The orthographic projection on the substrate has a width D of the i-th degree. i For example, the width D of the (i+1)th digit is... i+1 Width greater than or equal to the i-th width D i Wherein, the first direction X is parallel to the light-emitting surface of the light-emitting substrate. Alternatively, the first direction X is perpendicular to the light-emitting direction of the light-emitting substrate.

[0111] Through the design, the side wall angle of the concave surface in the sub-flat layer close to the light-emitting layer can be ensured to be small while the total number of the lens structures in the flat layer is increased, which is beneficial to improve the consistency of the film layer thickness in the light-emitting layer and improve the light-emitting uniformity.

[0112] FIG. 9 is a structural schematic diagram of a light-emitting substrate according to an example embodiment of the present disclosure.

[0113] For example, in some embodiments of the present disclosure, referring to FIG. 9, the flat layer 4 can include a first sub-flat layer 41 and a second sub-flat layer 42.

[0114] For example, the distribution density of the plurality of concave surfaces 402 in the first surface 421 of the second sub-flat layer 42 is substantially equal to the distribution density of the plurality of concave surfaces 401 in the first surface 411 of the first sub-flat layer 41.

[0115] For example, the second width D2 of the orthographic projection of at least one concave surface 402 in the first surface 421 of the second sub-flat layer 42 on the substrate is substantially equal to the first width D1 of the orthographic projection of at least one concave surface 401 in the first surface 411 of the first sub-flat layer 41 on the substrate.

[0116] For example, the second width D2 of the plurality of concave surfaces 402 in the first surface 421 of the second sub-flat layer 42 can be respectively equal to the first width D1 of the plurality of concave surfaces 401 in the first surface 411 of the first sub-flat layer 41.

[0117] It should be noted that “substantially equal” in the embodiments of the present disclosure means that the ratio of the two is within the range of 0.8-1.2.

[0118] Through the design, on the one hand, the side wall angle of the concave surface in the sub-flat layer close to the light-emitting layer can be ensured to be small while the total number of the lens structures in the flat layer is increased, which is beneficial to improve the consistency of the film layer thickness in the light-emitting layer and improve the light-emitting uniformity. On the other hand, the concave surface sizes of the first sub-flat layer and the second sub-flat layer are substantially the same, which can be formed by using the same type of imprinting template, which is beneficial to simplify the manufacturing process and reduce the production cost.

[0119] FIG. 10 is a structural schematic diagram of a light-emitting substrate according to an example embodiment of the present disclosure.

[0120] For example, in some embodiments of the present disclosure, referring to FIG. 10, the flat layer 4 can include a first sub-flat layer 41, a second sub-flat layer 42, and a third sub-flat layer 43.

[0121] Exemplarily, the distribution density of the plurality of concave surfaces 403 in the first surface 431 of the third sub-flat layer 43 is substantially equal to the distribution density of the plurality of concave surfaces 402 in the first surface 421 of the second sub-flat layer 42.

[0122] Exemplarily, the third width D3 of the orthographic projection of at least one concave surface 403 in the first surface 431 of the third sub-flat layer 43 on the substrate is substantially equal to the second width D2 of the orthographic projection of at least one concave surface 402 in the first surface 421 of the second sub-flat layer 42 on the substrate.

[0123] Exemplarily, the third width D3 of the plurality of concave surfaces 403 in the first surface 431 of the third sub-flat layer 43 can be respectively equal to the second width D2 of the plurality of concave surfaces 402 in the first surface 421 of the second sub-flat layer 42.

[0124] Through such a design, the total number (or distribution density) of the concave surface structures in the flat layer can be further increased, the light loss at the film layer interface can be better inhibited, the probability of total reflection phenomenon occurring can be reduced, and the light extraction efficiency of the light-emitting substrate can be improved. At the same time, the third sub-flat layer can also be formed with the same type of imprinting template as the first sub-flat layer, which is beneficial to simplify the manufacturing process and reduce the production cost.

[0125] In some embodiments of the present disclosure, the concave surface structures in the plurality of sub-flat layers can also adopt different designs. For example, the distribution density (or number), the side wall angle, the radius width, and the like of the plurality of concave surfaces of the first surface of the different sub-flat layers away from the substrate can be different or partially different.

[0126] FIG. 11 is a structural schematic diagram of a light-emitting substrate according to an exemplary embodiment of the present disclosure.

[0127] Exemplarily, in some embodiments of the present disclosure, referring to FIG. 11, the flat layer 4 can include a first sub-flat layer 41 and a second sub-flat layer 42.

[0128] Exemplarily, the distribution density of the plurality of concave surfaces 402 in the first surface 421 of the second sub-flat layer 42 is less than the distribution density of the plurality of concave surfaces 401 in the first surface 411 of the first sub-flat layer 41.

[0129] Exemplarily, the second width D2 of the orthographic projection of at least one concave surface 402 in the first surface 421 of the second sub-flat layer 42 on the substrate is greater than the first width D1 of the orthographic projection of at least one concave surface 401 in the first surface 411 of the first sub-flat layer 41 on the substrate.

[0130] By such a design, the inner diameter of the concave structure can be reduced in the sub-planar layer (e.g., the first sub-planar layer 41) not in direct contact with the light-emitting layer, the distribution density of the plurality of concaves is increased, so that the number of concave structures in the same area is more, which is conducive to better improving the light extraction effect of the planar layer and improving the light extraction efficiency of the light-emitting substrate.

[0131] FIG. 12 is a structural schematic diagram of a light-emitting substrate according to an example embodiment of the present disclosure.

[0132] For example, in some embodiments of the present disclosure, referring to FIG. 12, the planar layer 4 can include a first sub-planar layer 41, a second sub-planar layer 42, and a third sub-planar layer 43.

[0133] For example, the distribution density of the plurality of concaves 403 in the first surface 431 of the third sub-planar layer 43 is less than the distribution density of the plurality of concaves 402 in the first surface 421 of the second sub-planar layer 42.

[0134] For example, the third width D3 of the orthographic projection of at least one concave 403 in the first surface 431 of the third sub-planar layer 43 on the substrate substrate is greater than the second width D2 of the orthographic projection of at least one concave 402 in the first surface 421 of the second sub-planar layer 42 on the substrate substrate.

[0135] By such a design, the distribution density of the concaves in the planar layer can be further increased, which is conducive to better improving the light extraction effect of the planar layer and improving the light extraction efficiency of the light-emitting substrate.

[0136] FIG. 13 is a structural block diagram of a display panel according to an embodiment of the present disclosure.

[0137] Optionally, the embodiments of the present disclosure also provide a display panel, referring to FIG. 13, the display panel 200 can include the above-mentioned light-emitting substrate 100. It should be understood that the display panel has the same beneficial effects as the light-emitting substrate provided in the foregoing embodiments.

[0138] FIG. 14 is a structural block diagram of a display device according to an embodiment of the present disclosure.

[0139] Optionally, the embodiments of the present disclosure also provide a display device, referring to FIG. 14, the display device 300 can include the above-mentioned light-emitting substrate 100 or the display panel 200. The display device can include, but is not limited to, electronic paper, mobile phones, tablets, displays, notebooks, digital photo frames, navigation devices, and any product or component with display function. It should be understood that the display device has the same beneficial effects as the light-emitting substrate or the display panel provided in the foregoing embodiments.

[0140] While some embodiments of the general inventive concept have been shown and described, it is to be understood that changes can be made in embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.

Claims

1. A light-emitting substrate, characterized by, The application relates to a light-emitting substrate, comprising: a substrate substrate; a flat layer arranged on one side of the substrate substrate; and a light-emitting layer arranged on the side of the flat layer away from the substrate substrate, wherein the flat layer comprises N sub-flat layers arranged in a stack, the sub-flat layers comprise a first surface on the side away from the substrate substrate, the first surfaces of at least two of the sub-flat layers comprise a plurality of concave surfaces, and N is a positive integer greater than or equal to 2. The N sub-flat layers comprise an i-th sub-flat layer and an (i+1)-th sub-flat layer, the (i+1)-th sub-flat layer is arranged on the side of the i-th sub-flat layer away from the substrate substrate, 2. The light-emitting substrate according to claim 1, wherein wherein the refractive index of the (i+1)-th sub-flat layer is greater than or equal to the refractive index of the i-th sub-flat layer, i is a positive integer greater than or equal to 1 and less than or equal to N-1. The distribution density of the plurality of concave surfaces in the first surface of the (i+1)-th sub-flat layer is less than or equal to the distribution density of the plurality of concave surfaces in the first surface of the i-th sub-flat layer.

3. The light-emitting substrate of claim 2, wherein, In a first direction, the normal projection of at least one concave surface in the first surface of the (i+1)-th sub-flat layer on the substrate substrate has an (i+1)-th width, the normal projection of at least one concave surface in the first surface of the i-th sub-flat layer on the substrate substrate has an i-th width, and the (i+1)-th width is greater than or equal to the i-th width, wherein the first direction is parallel to the light-emitting surface of the light-emitting substrate.

4. The light-emitting substrate according to claim 2 or 3, wherein The side wall angle of at least one concave surface in the sub-flat layer is in the range of 30-40 degrees.

5. The light-emitting substrate according to any one of claims 1-4, wherein, The flat layer comprises a first sub-flat layer and a second sub-flat layer, 6. The light-emitting substrate of claim 4, wherein, wherein the distribution density of the plurality of concave surfaces in the first surface of the second sub-flat layer is substantially equal to the distribution density of the plurality of concave surfaces in the first surface of the first sub-flat layer; and the second width of the normal projection of at least one concave surface in the first surface of the second sub-flat layer on the substrate substrate is substantially equal to the first width of the normal projection of at least one concave surface in the first surface of the first sub-flat layer on the substrate substrate. The flat layer further comprises a third sub-flat layer, 7. The light-emitting substrate of claim 6, wherein, wherein the distribution density of the plurality of concave surfaces in the first surface of the third sub-flat layer is substantially equal to the distribution density of the plurality of concave surfaces in the first surface of the second sub-flat layer; and the third width of the normal projection of at least one concave surface in the first surface of the third sub-flat layer on the substrate substrate is substantially equal to the second width of the normal projection of at least one concave surface in the first surface of the second sub-flat layer on the substrate substrate. The flat layer comprises a first sub-flat layer and a second sub-flat layer, 8. The light-emitting substrate of claim 4, wherein, wherein the distribution density of the plurality of concave surfaces in the first surface of the second sub-flat layer is less than the distribution density of the plurality of concave surfaces in the first surface of the first sub-flat layer; and the second width of the normal projection of at least one concave surface in the first surface of the second sub-flat layer on the substrate substrate is greater than the first width of the normal projection of at least one concave surface in the first surface of the first sub-flat layer on the substrate substrate. The flat layer further comprises a third sub-flat layer, 9. The light-emitting substrate of claim 8, wherein, ​ The distribution density of the plurality of concaves in the first surface of the third sub-flat layer is less than the distribution density of the plurality of concaves in the first surface of the second sub-flat layer. The third width of the orthographic projection of at least one concave in the first surface of the third sub-flat layer on the substrate is greater than the second width of the orthographic projection of at least one concave in the first surface of the second sub-flat layer on the substrate.

10. The light emitting substrate of any of claims 1-9, wherein, The refractive index of the flat layer is in a range of 1.4 to 1.

9.

11. The light emitting substrate of claim 1, wherein, The material of the flat layer comprises a combination of one or more of epoxy resin, acrylic and polyimide.

12. The light emitting substrate of any of claims 2-4, wherein, The i-th sub-flat layer and the i+1-th sub-flat layer are in direct contact; and The sub-flat layer further comprises a second surface close to the substrate side, the second surface of the i+1-th sub-flat layer comprises a plurality of convexes, and the plurality of convexes in the second surface of the i+1-th sub-flat layer fill the plurality of concaves in the first surface of the i-th sub-flat layer.

13. The light emitting substrate of claim 1, wherein, The light-emitting layer comprises: a first electrode disposed on the side of the flat layer away from the substrate; a light-emitting functional layer disposed on the side of the first electrode away from the substrate; and a second electrode disposed on the side of the light-emitting functional layer away from the substrate, The first electrode is disposed in close contact with the surface of the flat layer away from the substrate; and The surface of the first electrode close to the substrate comprises a plurality of convexes; and / or The surface of the light-emitting functional layer close to the substrate comprises a plurality of convexes; and / or The surface of the second electrode close to the substrate comprises a plurality of convexes.

14. The light emitting substrate of claim 1, wherein, The light-emitting substrate further comprises: a driving circuit layer between the substrate and the flat layer; and a filter layer between the driving circuit layer and the flat layer.

15. A display panel, characterized by The display panel comprises the light-emitting substrate as claimed in any one of claims 1-14.

16. A display device comprising: The display panel comprises the light-emitting substrate as claimed in any one of claims 1-14 or the display panel as claimed in claim 15.

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