A light-emitting substrate and a method for preparing the same, and a display panel

Abstract

The present invention provides a light-emitting substrate and a preparation method thereof, and a display panel, and relates to the field of display technology. The light-emitting substrate comprises: a substrate, and a first pole, a light-emitting functional layer, a second pole, and a brightness enhancement layer stacked in sequence on the substrate; wherein the second pole is a light-emitting side electrode; the brightness enhancement layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightness enhancement layer comprises a plurality of sublayers, and the refractive index of the sublayer materials of two adjacent brightening layers is different. The light-emitting functional layer in the light-emitting substrate of the present invention has a high light extraction rate, and the optical performance of the light-emitting substrate is good, and the display effect of the display panel prepared by the light-emitting substrate is good.

Description

Technical Field

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

[0002] With the rapid development of display technology, OLED (Organic Light Emitting Device) display products have attracted widespread attention due to their self-luminescence, low power consumption, fast response, etc. However, the current market has higher requirements for the optical performance of OLED display products in order to further improve their display effect.

[0003] Currently, there is an urgent need to provide a new light-emitting substrate to solve the above problems. Summary of the invention

[0004] The embodiments of the present invention provide a light-emitting substrate and a preparation method thereof, and a display panel. The light-emitting substrate has good optical performance, and the display panel prepared from the light-emitting substrate has good display effect.

[0005] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0006] In one aspect, a light-emitting substrate is provided, comprising: a substrate, and a first electrode, a light-emitting functional layer, a second electrode and a brightness enhancement layer which are sequentially stacked on the substrate;

[0007] The second electrode is a light-exiting electrode; the brightness enhancement layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightness enhancement layer includes a plurality of sub-layers, and the refractive indexes of materials of two adjacent sub-layers of the brightness enhancement layer are different.

[0008] Optionally, the brightness enhancement layer comprises at least a first brightness enhancement sublayer, a second brightness enhancement sublayer and a third brightness enhancement sublayer which are stacked, and the first brightness enhancement sublayer is located between the second brightness enhancement sublayer and the second pole;

[0009] The refractive indices of the materials of the first brightness enhancing sub-layer, the second brightness enhancing sub-layer and the third brightness enhancing sub-layer increase in sequence.

[0010] Optionally, the light-emitting substrate further comprises a covering layer, and the covering layer is located between the second electrode and the brightness enhancement layer;

[0011] The refractive index of the material of each sub-layer of the brightness enhancement layer is smaller than the refractive index of the material of the cover layer.

[0012] Optionally, the material of the brightness enhancement layer includes at least two of inorganic non-metallic oxides, inorganic nitrides, inorganic oxynitrides, metal oxides or inorganic oxyfluorides.

[0013] Optionally, the light-emitting substrate further comprises a thin film encapsulation layer, and the thin film encapsulation layer is located on a side of the brightness enhancement layer away from the second pole;

[0014] The thin film encapsulation layer comprises a first encapsulation layer, a second encapsulation layer and a third encapsulation layer which are stacked, and the second encapsulation layer is located on a side of the first encapsulation layer away from the brightness enhancement layer;

[0015] The second encapsulation layer is configured to improve the light extraction rate of the light-emitting functional layer and release the internal stress in the first encapsulation layer and the third encapsulation layer.

[0016] Optionally, the second encapsulation layer is a single-layer film structure, and the refractive index of the material of the second encapsulation layer is in the range of 1.5-1.7.

[0017] Optionally, the thickness of the second encapsulation layer is in the range of 0.2-2 um.

[0018] Optionally, the material of the second encapsulation layer includes carbon nitride or carbon nitride oxide.

[0019] Optionally, the second encapsulation layer is a multilayer film structure including at least two sublayers, and the refractive indexes of materials of two adjacent sublayers of the second encapsulation layer are different.

[0020] Optionally, the four sublayers of the second encapsulation layer include a first inorganic sublayer, a second inorganic sublayer, a first organic sublayer and a third inorganic sublayer which are stacked; the third inorganic sublayer is in contact with the third encapsulation layer;

[0021] Alternatively, it includes a second organic sublayer, a third organic sublayer, a metal oxide sublayer and a fourth inorganic sublayer, and the fourth inorganic sublayer is in contact with the third encapsulation layer.

[0022] Optionally, the light-emitting substrate further includes a light-shielding layer and a switch tube; the switch tube is located between the first electrode and the light-shielding layer, and the first end of the switch tube is electrically connected to the first electrode;

[0023] The orthographic projection of the light-emitting functional layer on the substrate and the orthographic projection of the switch tube on the substrate at least partially overlap with the orthographic projection of the light-shielding layer on the substrate.

[0024] Optionally, the light-emitting substrate further includes a plurality of touch capacitors, and the touch capacitors are located on a side of the brightness enhancement layer away from the second electrode; each of the touch capacitors includes a first electrode layer and a second electrode layer; the second electrode layer is located on a side of the first electrode layer away from the brightness enhancement layer;

[0025] The second electrode layer includes a first sub-electrode, a second sub-electrode and a third sub-electrode arranged at intervals, and the first sub-electrode and the third sub-electrode are electrically connected to the first electrode layer respectively;

[0026] Among them, the first sub-electrode and the second sub-electrode form a first sub-capacitor, the second sub-electrode and the third sub-electrode form a second sub-capacitor, and the second sub-electrode and the first electrode layer form a third sub-capacitor; the first sub-capacitor, the second sub-capacitor and the third sub-capacitor constitute the touch capacitor.

[0027] Optionally, the light-emitting substrate further includes a pixel definition layer having a plurality of openings along a direction perpendicular to the substrate, the light-emitting functional layer is at least located within the openings, and the orthographic projection of the brightness enhancement layer on the substrate at least partially overlaps with the orthographic projection of the light-emitting functional layer on the substrate.

[0028] On the other hand, a display panel is provided, comprising the light-emitting substrate as described above.

[0029] In another aspect, a method for preparing a light-emitting substrate is provided, the method comprising:

[0030] providing a substrate;

[0031] A first electrode, a light-emitting functional layer, a second electrode and a brightening layer are formed in sequence; wherein the second electrode is a light-emitting side electrode; the brightening layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightening layer includes a plurality of sub-layers, and the refractive indices of the sub-layer materials of two adjacent brightening layers are different.

[0032] The embodiments of the present invention provide a light-emitting substrate and a method for preparing the same, and a display panel. The light-emitting substrate includes a substrate and a first electrode, a light-emitting functional layer, a second electrode, and a brightness enhancement layer which are sequentially stacked on the substrate; wherein the second electrode is a light-emitting side electrode; the brightness enhancement layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightness enhancement layer includes a plurality of sub-layers, and the refractive indexes of the sub-layer materials of two adjacent brightening layers are different. In the light-emitting substrate provided by the embodiments of the present invention, by providing a brightening layer having a plurality of sub-layer structures, and the refractive indexes of the sub-layers of adjacent brightening layers are different, the brightening layer can improve the light extraction rate of the light-emitting functional layer after the light emitted by the light-emitting functional layer passes through the second electrode and the brightening layer in sequence, thereby improving the transmittance of the light-emitting substrate, and further improving the optical properties of the display panel prepared by the light-emitting substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A schematic diagram of the structure of a display panel in a related technology provided by an embodiment of the present invention;

[0035] Figure 2 A schematic structural diagram of a light-emitting substrate provided by an embodiment of the present invention;

[0036] Figure 3 A schematic diagram of the structure of a display panel provided by an embodiment of the present invention;

[0037] Figure 4 A schematic diagram of the structure of another display panel provided by an embodiment of the present invention;

[0038] Figure 5 The transmittance simulation spectrum diagram of four brightness enhancement layers provided in the embodiment of the present invention;

[0039] Figure 6 A comparison diagram of the penetration spectrum of the light-emitting substrate provided in the embodiment of the present invention and the light-emitting substrate in the related art;

[0040] Figure 7 A color gamut comparison diagram of a light-emitting substrate provided by an embodiment of the present invention;

[0041] Figure 8 A comparison chart of blue light utilization rates of a light-emitting substrate provided by an embodiment of the present invention;

[0042] Fig. 9 A measured spectrum diagram of the transmittance of a light-emitting substrate provided in an embodiment of the present invention;

[0043] Fig.10a A schematic diagram of the lateral offset of light during refraction in a related technology provided by an embodiment of the present invention;

[0044] Fig.10b A schematic diagram of a light refraction path in a related technology provided by an embodiment of the present invention;

[0045] Fig.11a A brightness analysis diagram of an OLED light-emitting substrate at different viewing angles provided by an embodiment of the present invention;

[0046] Fig.11b A color shift comparison analysis diagram provided by an embodiment of the present invention;

[0047] Fig.12 A flow chart of a method for preparing a light-emitting substrate provided by an embodiment of the present invention;

[0048] Fig.13 A SEM image of a second encapsulation layer provided in an embodiment of the present invention;

[0049] Fig.14 A schematic diagram of peeling off a thin film encapsulation layer in a related technology provided by an embodiment of the present invention;

[0050] Fig.15 The reliability test result of a light-emitting substrate in a related technology provided by an embodiment of the present invention; wherein, Fig.15 Figure (A) shows the reliability test results of a display panel without an IJP layer in the related art; Fig.15 Figure (B) shows the reliability test result of a complete display panel in the related art;

[0051] Fig.16 A reliability test result of a light-emitting substrate provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] In the embodiments of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientation or position relationship indicated by the term "on" and the like is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the structure or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0054] To facilitate the clear description of the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as “first”, “second”, and “third” are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as “first”, “second”, and “third” do not limit the quantity.

[0055] like Figure 1 The structure diagram of the display panel in the related art is shown in FIG. Figure 1, an anode 2, a light-emitting functional layer 3 and a composite cathode layer 6 are sequentially arranged on a substrate 1, wherein the composite cathode layer 6 comprises a cathode layer (Ag or Mg), a cover layer (CPL layer) and a LiF light-emitting layer which are stacked; a first encapsulation layer 7, a second organic encapsulation layer 8 (IJP layer) and a third encapsulation layer 9 are sequentially arranged on the side of the LiF light-emitting layer away from the substrate 1; a barrier layer 4 (Bank) is also arranged on the third encapsulation layer 9, as well as a red quantum dot layer 16, a green quantum dot layer 17 and a red quantum dot layer 18 located between two adjacent barrier layers 4. In addition, the display panel also includes an interlayer dielectric layer 11, which covers the barrier layer 4, the red quantum dot layer 16, the green quantum dot layer 17 and the light-transmitting layer 10; the display panel also includes a black matrix layer 5, a red color filter layer (R) 18, a green color filter layer (G) 19 and a blue color filter layer (B) 12 located on the interlayer dielectric layer 11, a flat layer 13 covers the black matrix layer (BM) 5 and each color filter layer, and a bonding layer 14 is located between the cover plate 15 and the flat layer 13. It should be noted that Figure 1 The display panel shown uses OLED as backlight and QD as filter layer. It is a display product that combines OLED technology and QD technology.

[0056] However, due to the higher requirements on the optical properties of OLED display products and QD-OLED (Quantum Dot -Organic Light Emitting Device) display products in the market, the above-mentioned display panels can no longer meet the needs of users.

[0057] To this end, an embodiment of the present invention provides a light-emitting substrate, referring to Figure 2 or Figure 3 As shown, it includes: a substrate 45 and a first electrode 22, a luminous functional layer 23, a second electrode 25 and a brightening layer 27 which are stacked in sequence on the substrate 45; wherein the second electrode 25 is a light-emitting side electrode, the brightening layer (Luminous layer) 27 is configured to improve the light extraction rate of the luminous functional layer 23, and the brightening layer 27 includes a plurality of sub-layers, and the refractive indexes of two adjacent sub-layers of the brightening layer 27 are different.

[0058] The substrate 45 may be a rigid substrate, such as glass, or a flexible substrate, such as polyimide. The embodiment of the present invention is described by taking the substrate 45 as glass as an example.

[0059] The first electrode 22 may be an anode, and the second electrode 25 may be a cathode; or the first electrode 22 may be a cathode, and the second electrode 25 may be an anode; the specific configuration may be determined according to actual conditions, and is not limited here. It should be noted that the embodiments of the present invention are described by taking the first electrode 22 as an anode and the second electrode 25 as a cathode as an example.

[0060] The second pole 25 is a light-emitting side electrode in the sense that the light emitted by the light-emitting functional layer 23 passes through the second pole 25 and the brightness enhancement layer 27 in sequence and then emits out of the light-emitting substrate. The second pole 25 is closer to the light-emitting surface of the light-emitting substrate than the first pole 22. Therefore, the second pole 25 is called a light-emitting side electrode.

[0061] The above-mentioned multiple means: at least two. In practical applications, the specific number of sub-layers can be determined according to the actual product model.

[0062] The light-emitting functional layer 23 may include multiple film layers, for example: a hole injection layer (HIL layer), a hole transport layer (HTL layer), an organic transition buffer layer (Prime layer), a light-emitting layer (EML layer), a hole blocking layer (HBL layer) and an electron injection layer.

[0063] There is no limitation on the specific luminescent color of the luminescent functional layer 23. For example, the luminescent functional layer 23 may have one luminescent color, such as a luminescent functional layer with a blue luminescent color; or, it may have three luminescent colors, such as a luminescent functional layer with a red luminescent color, a luminescent functional layer with a green luminescent color, and a luminescent functional layer with a blue luminescent color.

[0064] In the case where the light-emitting functional layer 23 is a light-emitting functional layer having one color, the light-emitting functional layer 23 in the light-emitting substrate is used as a backlight; in the case where the light-emitting functional layer 23 includes a light-emitting functional layer having a red light-emitting color, a light-emitting functional layer having a green light-emitting color, and a light-emitting functional layer having a blue light-emitting color, the light-emitting functional layer 23 in the light-emitting substrate is used as a display. It should be noted that when the light-emitting functional layer 23 in the light-emitting substrate is used as a backlight, it can also be used as a display by providing a filter layer in the light-emitting substrate.

[0065] The material of the brightening layer 27 includes at least two of inorganic non-metallic oxides, inorganic nitrides, inorganic nitrogen oxides, metal oxides or inorganic fluorine oxides. Since the materials selected for each sublayer in the brightening layer 27 are different, the refractive indices of two adjacent sublayers in the brightening layer 27 are different.

[0066] The thickness of the brightness enhancement layer 27 is in the range of 600-2500 nm. For example, the thickness of the brightness enhancement layer 27 may be 850 nm, 1400 nm or 2075 nm.

[0067] In the brightness enhancement layer 27 provided in the embodiment of the present invention, the different refractive effects of the brightness enhancement layer 27 on the light emitted from the light-emitting functional layer 23 can be achieved by adjusting the material, thickness and film layer setting order of each sublayer in the brightness enhancement layer 27, thereby achieving optimization of the light output rate.

[0068] Specifically, the embodiments of the present invention provide the structures, materials and thickness information of four different brightness enhancement layers 27 as shown in Table 1 below.

[0069] Table 1: Examples of structures, materials and thicknesses of four brightness enhancement layers

[0070]

[0071] The specific situation of the first brightening layer (such as brightening layer A in Table 1) is as follows: it includes a first brightening sublayer, a second brightening sublayer and a third brightening sublayer located on the second pole 25 and stacked in sequence; the material of the first brightening sublayer is SiO2, the thickness is 350nm, and the refractive index is 1.48; the material of the second brightening sublayer is SiNX, the thickness is 300nm, and the refractive index is 1.65-1.84, and its refractive index can be controlled by adjusting the ratio of Si atoms and N atoms; the material of the third brightening sublayer is AL2O3, the thickness is 200nm, and the refractive index is 1.62.

[0072] The second brightening layer (such as brightening layer B in Table 1) also includes a first brightening sublayer, a second brightening sublayer and a third brightening sublayer located above the second pole 25 and stacked in sequence; the third brightening layer (such as brightening layer C in Table 1) also includes a first brightening sublayer, a second brightening sublayer and a third brightening sublayer located above the second pole 25 and stacked in sequence; the fourth brightening layer (such as brightening layer D in Table 1) includes a first brightening sublayer, a second brightening sublayer, a third brightening sublayer, a fourth brightening sublayer and a fifth brightening sublayer located above the second pole 25 and stacked in sequence. The specific details of the above-mentioned different brightening layers are shown in Table 1 and will not be repeated here.

[0073] In the light-emitting substrate provided in an embodiment of the present invention, a brightening layer 27 having a multiple sub-layer structure is provided, and the materials of two adjacent sub-layers of the brightening layer 27 have different refractive indices. This allows the light emitted by the light-emitting functional layer 23 to pass through the second electrode 25 and the brightening layer 27 in sequence. The brightening layer 27 can increase the light extraction rate of the light-emitting functional layer 23, thereby increasing the transmittance of the light-emitting substrate, and further increasing the optical properties of the display panel prepared using the light-emitting substrate.

[0074] In addition, in practical applications, since the LiF light-emitting layer on the cathode in the related art is very easy to absorb water, the bonding force between the LiF light-emitting layer and the encapsulation layer in contact with it is poor, making the encapsulation layer very easy to cause the following Fig.14The film peeling shown in the embodiment of the present invention causes packaging failure. In the light-emitting substrate provided by the embodiment of the present invention, the brightening layer 27 in the present application is used to replace the LiF light-emitting layer in the related art. On the one hand, the brightening layer 27 can improve the light extraction rate of the light-emitting functional layer 23; on the other hand, the brightening layer 27 has a good bonding force with the packaging layer, and it is not easy for the packaging layer to peel off the film layer, thereby ensuring the reliability of the display product and improving the quality of the product. On the other hand, the water and oxygen permeability of the brightening layer 27 is extremely low, and it has a strong water and oxygen barrier ability, and can also play a role in protecting the second electrode.

[0075] Furthermore, in addition to the four brightness enhancement layer structures in Table 1 above, the brightness enhancement layer 27 may also include more sub-layers made of other different materials and with different thicknesses, which are determined according to actual conditions.

[0076] Figure 5 The transmittance spectra of the four brightness enhancement layers in Table 1 above are obtained by data simulation (TFC simulation) in the visible light range. When the luminous color of the luminous functional layer is blue, that is, when the luminous substrate is used as a backlight substrate, since the wavelength range of blue light is 400-450nm, reference Figure 5 As shown, the order of transmittance of four different brightening layers in the wavelength range of blue light is: brightening layer B>brightening layer A>brightening layer C>brightening layer D. If it is necessary to increase the light output efficiency of the light-emitting functional layer with a blue luminescent color, one of the four brightening layers can be selected according to the actual demand for the increase in light output efficiency. Of course, according to the spectrum, it can be seen that brightening layer B has the most significant effect on improving the light output efficiency of the light-emitting functional layer with a blue luminescent color.

[0077] When the light-emitting functional layer includes a light-emitting functional layer with a red light-emitting color, a light-emitting functional layer with a green light-emitting color and a light-emitting functional layer with a blue light-emitting color, that is, when the above-mentioned light-emitting substrate is used as a display substrate, since the wavelength range of red light is 625-740nm, the wavelength range of green light is 490-580nm, and the wavelength range of blue light is 400-450nm, if the light output rate of the light-emitting functional layers of the above three colors is to be improved, according to simulation data, the transmittance of the brightening layer B in these three wavelength ranges is the largest.

[0078] Among them, the material of the first brightening sublayer of the brightening layer B is SiO2, and the refractive index is 1.48; the material of the second brightening sublayer of the brightening layer B is AL2O3, and the refractive index is 1.62; the material of the third brightening sublayer of the brightening layer B is SiNX, and the refractive index is 1.65-1.84, and its refractive index can be controlled by adjusting the ratio of Si atoms and N atoms; According to the above data, it can be obtained that when the brightening layer 27 includes the first brightening sublayer, the second brightening sublayer and the third brightening sublayer located on the second pole 25 and stacked in sequence, and the refractive index of the materials of the first brightening sublayer, the second brightening sublayer and the third brightening sublayer increases in sequence, the transmittance of the brightening layer under visible light is the largest, so that the brightening layer has a better effect on improving the light extraction rate of the light-emitting functional layer. In addition, it can be seen from the TFC simulation results that the light efficiency of the above-mentioned brightening layer 27 can be improved by 10% compared with the LiF light extraction layer in the related art.

[0079] Figure 6 The light transmission spectrum measured curves of the light-emitting substrate made of the brightness enhancement layer 27 provided by the embodiment of the present invention and the light-emitting substrate in the related art are shown in FIG. Figure 6 The light transmittance of the luminous substrate made by the brightness enhancement layer of the present invention is as high as 95%, while the light transmittance of the luminous substrate in the related art is 88%. It can be seen that the brightness enhancement layer provided by the embodiment of the present invention increases the light transmittance of the luminous substrate by 7%. Due to the increase in light transmittance, the optical performance (such as NTSC color gamut) of the luminous substrate is also greatly improved. It should be noted that the above Figure 6 The two groups of light-emitting substrates used for testing are only different in the brightness enhancement layer and the LiF light-emitting layer, that is, the structure of the light-emitting substrate of the present application is obtained by using the brightness enhancement layer to replace the LiF light-emitting layer of the light-emitting substrate in the related art.

[0080] Optional, reference Figure 2 As shown, the light-emitting substrate further includes a covering layer 26 , which is located between the second electrode 25 and the brightness enhancement layer 27 ; wherein the refractive index of the material of each sublayer of the brightness enhancement layer 27 is smaller than the refractive index of the material of the covering layer 26 .

[0081] The cover layer 26 is also called a CPL layer. The refractive index of the material of the CPL layer is 1.85. Figure 5 The transmittance simulation spectra of various brightening layers 27 are all based on the CPL layer as the light incident layer, so that the light passes through the CPL layer and the brightening layer 27 in turn. The simulation results show through data comparison that when the refractive index of the material of each sub-layer of the brightening layer 27 is smaller than the refractive index of the material of the CPL layer, the brightening layer 27 has a more significant effect on improving the light output efficiency of the light-emitting functional layer 23.

[0082] The material of the brightness enhancement layer includes at least two of inorganic non-metallic oxides, inorganic nitrides, inorganic oxynitrides, metal oxides or inorganic fluorooxides.

[0083] Specifically, the inorganic non-metallic oxide may be silicon oxide, the inorganic nitride may be silicon nitride, the inorganic oxynitride may be silicon oxynitride, the metal oxide may be aluminum oxide, magnesium oxide, titanium oxide or zinc oxide, and the inorganic oxyfluoride may be silicon oxyfluoride.

[0084] Optional, reference Figure 2 As shown, the light-emitting substrate also includes a thin film encapsulation layer (not marked), which is located on the side of the brightness enhancement layer 27 away from the second pole 25; the thin film encapsulation layer includes a first encapsulation layer 28, a second encapsulation layer 29 and a third encapsulation layer 30 which are stacked, and the second encapsulation layer 29 is located on the side of the first encapsulation layer 28 away from the brightness enhancement layer 27; wherein the second encapsulation layer 29 is configured to improve the light extraction rate of the light-emitting functional layer 23 and release the internal stress in the first encapsulation layer 28 and the third encapsulation layer 30.

[0085] The first encapsulation layer and the third encapsulation layer are both made of inorganic materials, and the thickness of the first encapsulation layer is 1 um, and the thickness of the third encapsulation layer is 0.6 um.

[0086] The above-mentioned second encapsulation layer can be a single film layer structure or a multi-film layer structure. For example, it can be a single film layer structure of SiCxNy, or a single film layer structure of SiOCxNy; or it can also be a multi-film layer structure composed of SiNX layer, SiCN layer, SiNX layer and SiO2 layer, or a multi-film layer structure composed of SiNX layer, AL2O3 layer, Parylene layer and organic layer.

[0087] A second encapsulation layer is provided in the light-emitting substrate provided by the present invention. On the one hand, compared with the IJP layer with a thickness of up to 10 um in the related art, the second encapsulation layer can greatly improve the light extraction rate of the light-emitting functional layer. Figure 8 The figure shows a comparative analysis of the blue light utilization of the light-emitting substrate in the related art, the display panel in the related art, and the light-emitting substrate prepared by the thin film encapsulation layer provided in the embodiment of the present application when the light-emitting color of the light-emitting functional layer is blue. Figure 8As shown, when the luminous color of the luminescent functional layer is blue, for different models of product 1, product 2, product 3 and product 4, the blue light utilization rate of the luminescent substrate prepared by the second encapsulation layer provided by the embodiment of the present invention is much higher than the blue light utilization rate of the luminescent substrate prepared by the IJP layer in the related art. In addition, since a cover glass or a protective film is formed on the luminescent substrate to form a display panel, the blue light utilization rate of the display panel in the related art is slightly lower than the blue light utilization rate of the luminescent substrate in the related art. Even so, since the blue light utilization rate of the luminescent substrate provided by the embodiment of the present invention is much higher than the luminescent substrate in the related art, it can be inferred that the blue light utilization rate of the display panel made of the luminescent substrate provided by the embodiment of the present invention is also much higher than the blue light utilization rate of the display panel in the related art.

[0088] On the other hand, Figure 7 The color gamut comparison analysis diagram of the light-emitting substrate in the related art, the display panel in the related art and the light-emitting substrate provided by the embodiment of the present application is shown. Figure 7 As shown, due to the improvement of blue light utilization, the blue light brightness of the luminous substrate is greatly improved, thereby improving the color gamut (NTSC) of the luminous substrate. It should be noted that the luminous color of the luminous functional layer of the luminous substrate here is blue, and the luminous substrate also includes a color filter layer located on the luminous functional layer, and the luminous substrate is used for display. In addition, the above conclusions are applicable to different models of products a, product b, product c and product d. The above color gamut can actually be called a color space.

[0089] On the other hand, the second encapsulation layer in the light-emitting substrate provided by the embodiment of the present invention can also replace the IJP layer in the related art to release the internal stress in the first encapsulation layer and the third encapsulation layer. On the other hand, since the second encapsulation layer covers the first encapsulation layer, the second encapsulation layer containing organic materials can wrap foreign matter (particles) not covered by the first encapsulation layer, thereby preventing foreign matter from corroding the structure of the light-emitting substrate, thereby improving the reliability of the light-emitting substrate.

[0090] Table 2: Examples of structures, materials and thicknesses of three second encapsulation layers

[0091]

[0092] Table 2 provides three examples of the structure, material and thickness of the second encapsulation layer. Specifically, the first second encapsulation layer is as follows:

[0093] The first second encapsulation layer is a single-layer film structure, and its material includes carbon nitride or carbon nitride oxide; for example, SiCxNy or SiOCxNy. It should be noted that SiOCxNy is obtained by oxidation of SiCxNy, and its oxygen content can be controlled by controlling the oxidation treatment time; the refractive index range of the material of the first second encapsulation layer is 1.5-1.7, and the specific refractive index can be adjusted by controlling the proportion of each element; the thickness range of the first second encapsulation layer is 0.2-2um. The light transmittance spectrum of the light-emitting substrate prepared by the first second encapsulation layer is as follows: Fig. 9 As shown, its transmittance (also called light transmittance) is 95%, which is 7% higher than the light transmittance of the light-emitting substrate in the related art. Fig.13 FIG. 2 shows a local SEM image of a light-emitting substrate prepared by a second encapsulation layer 29 of a single-layer film structure, as shown in FIG. Fig.13 As shown, the second encapsulation layer 29 of a single-layer film structure whose material composition is SiCxNy is located between the first encapsulation layer 28 and the third encapsulation layer 30.

[0094] The second encapsulation layer of the above-mentioned single-layer film structure uses C2H2, SiH4, NH3, and H2 as gas sources and adopts CVD (Chemical Vapor Deposition) process to form a second encapsulation layer with a material composition of SiCxNy; or further oxidizes SiCxNy to form a second encapsulation layer with a material composition of SiOCxNy; by controlling the film thickness range to 0.2-2um, it is much smaller than the thickness of the IJP layer (10um) in the related art. The second encapsulation layer of the single-layer film structure can cover and wrap the particles and foreign matter on the surface of the first encapsulation layer, eliminate pinholes (pinholes refer to the pores on the rough surface of the first encapsulation layer), and make the surface of the first encapsulation layer smoother; it can also eliminate the internal stress in the first encapsulation layer and the second encapsulation layer to enhance the flexibility and reliability of the entire thin film encapsulation layer.

[0095] Furthermore, since the thickness of the second encapsulation layer provided by the embodiment of the present invention is much smaller than the thickness of the IJP layer in the related art, the thinning of the thickness has a very positive effect on the color gamut and light utilization rate of the light-emitting substrate. In addition, since the proportion of each element in the second encapsulation layer material of the above-mentioned single-layer film structure can be adjusted by controlling the preparation process parameters, and then its refractive index can be adjusted, compared with the refractive index of the IJP layer in the related art that is not adjustable, the second encapsulation layer of the single-layer film structure provided by the embodiment of the present invention can be applied to different types of products and optimize the viewing angle according to the actual conditions of different products.

[0096] Fig.11a The figure shows a schematic diagram of a model of light emission from an OLED light-emitting substrate. Fig.11aThe structure in Figure 4 illustrates how the second encapsulation layer optimizes the viewing angle.

[0097] refer to Fig.11a In the related art, as the viewing angle increases (referring to Fig.11a The absolute value of the viewing angle increases), when the light passes through the first packaging layer 28 and enters the second packaging layer 29, total reflection occurs, so that the brightness at a large viewing angle gradually decreases, and then the display effect is not good when the viewer watches from the side. In the embodiment of the present invention, by using the second packaging layer 29 with a single-layer film structure and a material composition of SiCxNy, the angle of total reflection of the side-incident light is increased compared to the IJP layer in the related art. For example, in the related art, the incident light a is totally reflected, while in the present application, the incident light b is totally reflected, wherein the incident angle of light a is less than the incident angle of light b; thereby increasing the probability of the side-incident light emitting from the light exit surface of the second packaging layer 29, thereby increasing the light entering the human eye from the side viewing angle, and then increasing the brightness of the side viewing angle, thereby achieving the effect of optimizing the viewing angle.

[0098] In addition, the thickness of the second encapsulation layer is adjusted to adjust the light and further increase the brightness at the side viewing angle. Fig.10a This is a relationship diagram of the influence of film thickness on the lateral displacement of light after refraction in the related art. Fig.10b is a schematic diagram of the deviation of light during refraction in the related art, Fig.10b It can be seen that: X1=d1*tanθ1, X2=d2*tanθ2, where d1 is the thickness of film layer 1, d2 is the thickness of film layer 2, and the offset of the light after passing through film layer 2 from film layer 1 is X1+X2. Fig.10b The principle is similar to that in Fig.10a It is a line graph of the offset of light after passing through the 8 film layers of the stacked arrangement. It should be noted that, when the material and refractive index of each film layer are determined, as the total film thickness increases, the lateral offset of the light increases. The lateral offset is the offset of the light in the direction parallel to the substrate after refraction. The larger the lateral offset of the light, the more light is emitted from the side viewing angle. However, as the film thickness increases, the light loss will also increase, and the brightness at the front viewing angle will decrease. In actual applications, it is necessary to determine the balance point of the brightness at the front viewing angle and the side viewing angle based on the actual design of each display product and the optical characteristics specifications of the front viewing angle and the side viewing angle. It should be noted that the above Fig.10a and Fig.10b They are all used to illustrate the phenomenon that the emission position of light is offset after the light is refracted, so as to assist in understanding how to optimize the viewing angle by adjusting the film structure. For specific optical knowledge, please refer to the relevant technology and will not be repeated here.

[0099] Optionally, the second encapsulation layer is a multilayer film structure including at least two sublayers, and the refractive indices of materials of two adjacent sublayers in the second encapsulation layer are different.

[0100] Specifically, as shown in Table 2 above, the specific situation of the second second encapsulation layer is as follows:

[0101] The second second encapsulation layer includes a second organic sublayer, a third organic sublayer Parylene layer, a metal oxide sublayer AL2O3 layer and a fourth inorganic sublayer SiNX layer, which are located on the first encapsulation layer 28 in sequence, and the fourth inorganic sublayer SiNX layer is in contact with the third encapsulation layer 30. The transmittance of the light-emitting substrate prepared using the third second encapsulation layer is also 95%, which is 7% higher than the transmittance of the light-emitting substrate in the related art.

[0102] Specifically, as shown in Table 2 above, the specific situation of the third second encapsulation layer is as follows:

[0103] The third type of second encapsulation layer includes a first inorganic sublayer SiO2 layer, a second inorganic sublayer SiNX layer, a first organic sublayer SiCN layer and a third inorganic sublayer SiNX layer, which are located on the first encapsulation layer 28 and are stacked in sequence; the third inorganic sublayer SiNX layer is in contact with the third encapsulation layer 30; the transmittance of the light-emitting substrate prepared using the second second encapsulation layer is also 91%, which is 3% higher than the transmittance of the light-emitting substrate in the related technology.

[0104] The specific materials and thicknesses of the second type second encapsulation layer and the third type second encapsulation layer are shown in Table 2 above, and are not described here in detail. It should be noted that the specific material of the second organic sublayer is not limited here; in addition, the Parylene is also called polyparaxylene coating.

[0105] Furthermore, the second second encapsulation layer and the third second encapsulation layer having a multi-layer film structure can not only improve the light transmittance, but also improve the color shift problem at a side viewing angle to a certain extent. Fig.11b The display panel (corresponding to Fig.11b Experimental group 1), display panel prepared with the third second encapsulation layer (corresponding to Fig.11b Experimental group 2) and display panels in related technologies (corresponding to Fig.11b Color shift curves at different viewing angles (control group in the figure). Fig.11bAs shown, within the viewing angle range of 0-58°, the color deviation of the display panel prepared by the second second encapsulation layer and the display panel prepared by the third second encapsulation layer are both smaller than the color deviation of the display panel in the related art, and when the viewing angle is 40°, the color deviation of the display panel prepared by the second second encapsulation layer is reduced from 0.11 in the related art to 0.01. Obviously, the display panel prepared by the second encapsulation layer with a multi-layer film structure of the present invention can greatly improve the color deviation problem of the display panel in the related art.

[0106] Optional, reference Figure 3 As shown, the light-emitting substrate also includes a shading layer 46 and a switching tube 44; the switching tube 44 is located between the first pole 22 and the shading layer 46, and the first end of the switching tube 44 is electrically connected to the first pole 22; wherein the orthographic projection of the light-emitting functional layer 23 on the substrate 45 and the orthographic projection of the switching tube 44 on the substrate 45 both at least partially overlap with the orthographic projection of the shading layer 46 on the substrate 45.

[0107] It should be noted that Figure 3 The structure shown is a display panel obtained after forming a filling layer (Filter) 42, a barrier layer (Dam) 50 and a cover plate 43 on the light-emitting substrate. The embodiment of the present invention does not depict the structure of the light-emitting substrate. Figure 3 The display panel in the embodiment includes the above-mentioned light-emitting substrate. Figure 3 The positions of the light shielding layer 46 and the switch tube 44 are explained by taking the display panel of FIG.

[0108] The switch tube 44 is a thin film transistor, which includes a gate, a source, a drain and an active layer. The active layer includes a semiconductor region and a conductor region located on both sides of the semiconductor region. The material of the active layer may include any one of polycrystalline silicon, single crystal silicon or indium gallium zinc oxide (IGZO).

[0109] In addition, the first end of the switch tube may be a source or a drain, depending on the actual product.

[0110] The light-emitting substrate provided by the embodiment of the present invention is configured such that the orthographic projection of the light-emitting functional layer 23 on the substrate 45 and the orthographic projection of the switch tube 44 on the substrate 45 overlap with the orthographic projection of the light-shielding layer 46 on the substrate 45, so that the light-shielding layer can block the influence of the light taken in from the outside on the photoelectric characteristics of the switch tube, thereby extending the service life of the light-emitting tube; in addition, the light emitted from the light-emitting functional layer toward the substrate can be reflected back to the light-emitting side, thereby improving the utilization rate of the light.

[0111] Of course, reference Figure 3As shown, the light-emitting substrate provided in the embodiment of the present invention may further include a first buffer layer (Buffer) 47, an interlayer dielectric layer (ILD) 48, an insulating layer (PVX & PLN) 49, a pixel definition layer 24, a black matrix layer 33, a color filter layer 34 and a first flat layer (OC) 41. The specific structures of the first buffer layer (Buffer) 47, the interlayer dielectric layer (ILD) 48, the insulating layer (PVX & PLN) 49, the pixel definition layer 24, the black matrix layer 33, the color filter layer 34 and the first flat layer (OC) 41 included in the above-mentioned light-emitting substrate are not limited here, and can be determined according to actual conditions.

[0112] Optional, reference Figure 2 As shown, the light-emitting substrate further includes a plurality of touch capacitors 35, and the touch capacitors 35 are located on a side of the brightness enhancement layer 27 away from the second electrode 25; each touch capacitor 35 includes a first electrode layer and a second electrode layer; the second electrode layer is located on a side of the first electrode layer away from the brightness enhancement layer 27;

[0113] The second electrode layer includes a first sub-electrode, a second sub-electrode and a third sub-electrode arranged at intervals, and the first sub-electrode and the third sub-electrode are electrically connected to the first electrode layer respectively;

[0114] The first sub-electrode and the second sub-electrode form a first sub-capacitor, the second sub-electrode and the third sub-electrode form a second sub-capacitor, and the second sub-electrode and the first electrode layer form a third sub-capacitor; the first sub-capacitor, the second sub-capacitor and the third sub-capacitor constitute a touch capacitor 35.

[0115] The light-emitting substrate provided in the embodiment of the present invention may further include a second buffer layer (not shown), a second flat layer 31 and a third flat layer 32 located on the third encapsulation layer 30, wherein the second flat layer 31 covers the first electrode layer, and the third flat layer 32 covers the second electrode layer. Similarly, the specific structures of the second buffer layer (not shown), the second flat layer 31 and the third flat layer 32 included in the light-emitting substrate are not limited here, and can be determined according to actual conditions.

[0116] The light-emitting substrate provided by the embodiment of the present invention integrates the touch capacitor into the light-emitting substrate by arranging the touch capacitor on the third packaging layer, thereby simplifying the film layer structure and reducing the cost while realizing the touch function.

[0117] It should be noted that the size and specific number of the touch capacitors are not limited here and can be determined according to actual conditions.

[0118] Optional, reference Figure 4As shown, the light-emitting substrate also includes a pixel definition layer 24, which has a plurality of openings along a direction perpendicular to the substrate 45, the light-emitting functional layer 23 is at least located within the opening, and the orthographic projection of the brightening layer 27 on the substrate 45 at least partially overlaps with the orthographic projection of the light-emitting functional layer 23 on the substrate 45.

[0119] It should be noted that Figure 4 The structure shown is a display panel obtained after forming an adhesive layer (OCA) 36 and a protective film 37 on the light-emitting substrate. The embodiment of the present invention does not depict the structure of the light-emitting substrate. Figure 4 The display panel in the embodiment includes the above-mentioned light-emitting substrate. Figure 4 The structure of the pixel definition layer is explained using a display panel as an example.

[0120] The meaning of the light-emitting functional layer 23 being at least located in the opening is that: the light-emitting functional layer 23 is only located in the opening; or, the light-emitting functional layer 23 is located in the opening and also extends to the surface of the pixel definition layer outside the opening, covering part of the pixel definition layer; or, the light-emitting functional layer 23 is located in the opening and also extends to the surface of the pixel definition layer outside the opening, covering all of the pixel definition layer.

[0121] An embodiment of the present invention further provides a display panel, comprising the light-emitting substrate as described above.

[0122] Figure 3 and Figure 4 The specific structures of two display panels provided by the embodiments of the present invention are shown. Figure 3 The structure shown is a display panel formed after a filling layer (Filter) 42, a barrier layer (Dam) 50 and a cover plate 43 are formed on the light-emitting substrate. Figure 4 The structure shown is a display panel formed after forming an adhesive layer (OCA) 36 and a protective film 37 on the light-emitting substrate provided in the embodiment of the present invention. The structure of the display panel is not limited here, and can be specifically configured and adjusted according to actual conditions.

[0123] Fig.15 The middle (B) figure shows the reliability test result of the display panel when the IJP layer is set in the related art. It can be seen that the display panel has no abnormality after the reliability test, but its light transmittance cannot meet the requirements; Fig.15 Figure (A) shows the reliability test results of a display panel without an IJP layer in the related art. The light transmittance of the display panel without an IJP layer in the related art is improved to a certain extent compared with the display panel with an IJP layer. However, due to the internal stress in the first encapsulation layer and the second encapsulation layer, there is no buffering effect of the IJP layer, so that after the reliability test, the display panel has serious abnormalities.

[0124] Fig.16 The results of the display panel made of the light-emitting substrate provided in the embodiment of the present invention before the reliability test (RA 0 hours) and after the reliability test (RA 240 hours) are shown. It can be seen that after replacing the IJP layer with the second encapsulation layer and the LiF layer with the brightness enhancement layer in the present application, the optical properties of the display panel are improved and the reliability test is passed.

[0125] It should be noted that the above reliability test (RA) is as follows: the display panel is placed in an environment with a temperature of 85°C and a humidity of 85% for 240 hours without power supply. After being taken out, it is placed at room temperature to check whether the appearance is abnormal and whether there are bright spots or dark spots on the screen after it is lit.

[0126] The display panel provided by the embodiment of the present invention has a brightening layer 27 with a multiple sub-layer structure, and the materials of two adjacent sub-layers of the brightening layer 27 have different refractive indices. Therefore, after the light emitted by the light-emitting functional layer 23 passes through the second electrode 25 and the brightening layer 27 in sequence, the brightening layer 27 can increase the light extraction rate of the light-emitting functional layer 23, thereby improving the transmittance of the light-emitting substrate, and further improving the optical properties of the display panel prepared by the light-emitting substrate.

[0127] The embodiment of the present invention also provides a method for preparing a light-emitting substrate. Fig.12 As shown, the method includes:

[0128] S01, providing a substrate 45;

[0129] S02, sequentially forming a first electrode 22, a light-emitting functional layer 23, a second electrode 25 and a brightening layer 27; wherein the brightening layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightening layer includes multiple sub-layers, and the refractive indexes of the sub-layer materials of two adjacent brightening layers are different.

[0130] In the light-emitting substrate prepared by the preparation method provided in the embodiment of the present invention, by providing a brightness enhancement layer 27 having a plurality of sub-layer structures, and the materials of the adjacent sub-layers of the brightness enhancement layer 27 have different refractive indices, the light emitted by the light-emitting functional layer 23 passes through the second electrode 25 and the brightness enhancement layer in sequence, and the brightness enhancement layer can improve the light extraction rate of the light-emitting functional layer, thereby improving the transmittance of the light-emitting substrate, and further improving the optical properties of the display panel prepared by the light-emitting substrate. The above preparation method is simple and has high preparation efficiency.

[0131] Below Figure 2 Taking the structure of the light-emitting substrate shown in FIG. 1 as an example, the preparation method of the light-emitting substrate is described as follows:

[0132] S1, forming a substrate 21;

[0133] The substrate 21 may include at least Figure 3 The substrate 45, the light shielding layer 46, the first buffer layer (Buffer) 47, the interlayer dielectric layer (ILD) 48, the switch tube 44 and the insulating layer (PVX & PLN) 49 are shown in FIG. Of course, the above-mentioned base 21 may also include other structures, which are not limited here and can be determined according to actual conditions.

[0134] S2, forming a first electrode 22 on the substrate 21;

[0135] S3, forming a pixel definition layer 24 on the first electrode 22; wherein the pixel definition layer has a plurality of openings along a direction perpendicular to the substrate;

[0136] S4, forming a light-emitting function layer 23 on a pixel definition layer (PDL) 24;

[0137] S5. Form a second electrode 25 on the light-emitting functional layer 23, wherein the second electrode is formed by vapor deposition using Ag and Mg as raw materials.

[0138] S6, forming a cap layer 26 (CPL layer) on the second electrode 25;

[0139] S7, forming a brightness enhancement layer 27 on the cover layer 26;

[0140] S8 forms a first encapsulation layer 28 on the brightness enhancement layer 27 by using a CVD method;

[0141] S9, using C2H2, SiH4, NH3, H2 as gas sources, using CVD method to form the second encapsulation layer 29 on the first encapsulation layer 28;

[0142] S10, forming a third encapsulation layer 30 on the second encapsulation layer 29;

[0143] S11, forming a first electrode layer;

[0144] S12, forming a second planar layer 31 on the first electrode layer;

[0145] S13, forming a second electrode layer on the second flat layer 31; wherein the second electrode layer includes a first sub-electrode, a second sub-electrode and a third sub-electrode arranged at intervals, and the first sub-electrode and the third sub-electrode are electrically connected to the first electrode layer respectively; the first sub-electrode and the second sub-electrode form a first sub-capacitor, the second sub-electrode and the third sub-electrode form a second sub-capacitor, and the second sub-electrode and the first electrode layer form a third sub-capacitor; the first sub-capacitor, the second sub-capacitor and the third sub-capacitor constitute a touch capacitor 35;

[0146] S14, forming a third planar layer 32 on the second electrode layer;

[0147] S15, forming a black matrix layer 33 on the third planar layer 32;

[0148] S16 , forming a color filter layer 34 on the third planar layer 32 .

[0149] Of course, the preparation method of the above-mentioned light-emitting substrate also includes other steps. Only the steps related to the invention are introduced here. Other structures and their preparation steps except the incremental film and the second encapsulation layer are not limited here. For details, please refer to the structure and preparation process of the light-emitting substrate in the relevant technology, which will not be repeated here.

[0150] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A light-emitting substrate, characterized in that: include: A substrate and a first electrode, a light-emitting functional layer, a second electrode, a covering layer, a brightness enhancement layer and a thin-film encapsulation layer stacked in sequence on the substrate; Wherein, the second electrode is a light-exiting side electrode; the brightness enhancement layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightness enhancement layer includes a plurality of sub-layers, and the refractive indexes of materials of two adjacent sub-layers of the brightness enhancement layer are different; The cover layer is located between the second pole and the brightness enhancement layer, and the refractive index of the material of each sublayer of the brightness enhancement layer is smaller than the refractive index of the material of the cover layer; The thin film encapsulation layer is located on a side of the brightness enhancement layer away from the second pole; the thin film encapsulation layer comprises a first encapsulation layer, a second encapsulation layer and a third encapsulation layer which are stacked, and the second encapsulation layer is located on a side of the first encapsulation layer away from the brightness enhancement layer.

2. The light-emitting substrate according to claim 1, characterized in that: The brightness enhancement layer at least comprises a first brightness enhancement sublayer, a second brightness enhancement sublayer and a third brightness enhancement sublayer which are stacked, and the first brightness enhancement sublayer is located between the second brightness enhancement sublayer and the second pole; The refractive indices of the materials of the first brightness enhancing sub-layer, the second brightness enhancing sub-layer and the third brightness enhancing sub-layer increase in sequence.

3. The light-emitting substrate according to claim 1, characterized in that: The material of the brightness enhancement layer includes at least two of inorganic non-metallic oxides, inorganic nitrides, inorganic oxynitrides, metal oxides or inorganic fluorooxides.

4. The light-emitting substrate according to claim 1, characterized in that: The second encapsulation layer is configured to improve the light extraction efficiency of the light emitting functional layer and release internal stress in the first encapsulation layer and the third encapsulation layer.

5. The light-emitting substrate according to claim 1, characterized in that: The second encapsulation layer is a single-layer film structure, and the refractive index of the material of the second encapsulation layer is in the range of 1.5-1.

7.

6. The light-emitting substrate according to claim 1, characterized in that: The thickness of the second encapsulation layer is in the range of 0.2-2 um.

7. The light-emitting substrate according to claim 5, characterized in that: The material of the second encapsulation layer includes carbon nitride or carbon nitride oxide.

8. The light emitting substrate according to claim 1, characterized in that: The second encapsulation layer is a multilayer film structure including at least two sublayers, and the refractive indexes of materials of two adjacent sublayers of the second encapsulation layer are different.

9. The light-emitting substrate according to claim 8, characterized in that: The four sublayers of the second encapsulation layer include a first inorganic sublayer, a second inorganic sublayer, a first organic sublayer and a third inorganic sublayer which are stacked; the third inorganic sublayer is in contact with the third encapsulation layer; Alternatively, it includes a second organic sublayer, a third organic sublayer, a metal oxide sublayer and a fourth inorganic sublayer, and the fourth inorganic sublayer is in contact with the third encapsulation layer.

10. The light emitting substrate according to claim 1, characterized in that: The light-emitting substrate further includes a light-shielding layer and a switch tube; the switch tube is located between the first electrode and the light-shielding layer, and a first end of the switch tube is electrically connected to the first electrode; The orthographic projection of the light-emitting functional layer on the substrate and the orthographic projection of the switch tube on the substrate at least partially overlap with the orthographic projection of the light-shielding layer on the substrate.

11. The light emitting substrate according to claim 1, characterized in that: The light-emitting substrate further comprises a plurality of touch capacitors, and the touch capacitors are located on a side of the brightness enhancement layer away from the second electrode; each of the touch capacitors comprises a first electrode layer and a second electrode layer; the second electrode layer is located on a side of the first electrode layer away from the brightness enhancement layer; The second electrode layer includes a first sub-electrode, a second sub-electrode and a third sub-electrode arranged at intervals, and the first sub-electrode and the third sub-electrode are electrically connected to the first electrode layer respectively; Among them, the first sub-electrode and the second sub-electrode form a first sub-capacitor, the second sub-electrode and the third sub-electrode form a second sub-capacitor, and the second sub-electrode and the first electrode layer form a third sub-capacitor; the first sub-capacitor, the second sub-capacitor and the third sub-capacitor constitute the touch capacitor.

12. The light-emitting substrate according to any one of claims 1 to 11, characterized in that: The light-emitting substrate also includes a pixel definition layer, which has a plurality of openings along a direction perpendicular to the substrate. The light-emitting functional layer is at least located within the openings, and the orthographic projection of the brightness enhancement layer on the substrate at least partially overlaps with the orthographic projection of the light-emitting functional layer on the substrate.

13. A display panel, characterized in that: It comprises the light emitting substrate as claimed in any one of claims 1 to 12.

14. A method for preparing a light-emitting substrate according to any one of claims 1 to 12, characterized in that: The method comprises: providing a substrate; A first electrode, a light-emitting functional layer, a second electrode, a covering layer, a brightness enhancement layer and a thin film encapsulation layer are sequentially formed; wherein the second electrode is a light-emitting side electrode; the brightness enhancement layer is configured to improve the light extraction rate of the light-emitting functional layer, and the brightness enhancement layer includes a plurality of sub-layers, and the refractive indexes of materials of two adjacent sub-layers of the brightness enhancement layer are different; The cover layer is located between the second pole and the brightness enhancement layer, and the refractive index of the material of each sublayer of the brightness enhancement layer is smaller than the refractive index of the material of the cover layer; The thin film encapsulation layer is located on a side of the brightness enhancement layer away from the second pole; the thin film encapsulation layer comprises a first encapsulation layer, a second encapsulation layer and a third encapsulation layer which are stacked, and the second encapsulation layer is located on a side of the first encapsulation layer away from the brightness enhancement layer.

Images