Preparation method of display panel, display panel and display device

Abstract

The invention provides a preparation method of a display panel, the display panel and a display device.The display panel comprises a substrate, a pixel definition layer, a first electrode layer, a light-emitting device layer, a second electrode layer, a heat absorption layer and a packaging layer, and the pixel definition layer, the first electrode layer, the light-emitting device layer, the second electrode layer, the heat absorption layer and the packaging layer are sequentially stacked on the substrate. Any pixel opening is located between the adjacent pixel definition structures, the first electrode layer is arranged in the pixel opening, and the orthographic projection of the heat absorption layer on the substrate is not overlapped with the orthographic projection of the pixel opening on the substrate. Compared with the prior art, the display panel has the advantages that the luminous efficiency and the light extraction efficiency of the luminous device layer are not affected while thermal decomposition of the luminous material is relieved, and the service life of the display panel is prolonged.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and more specifically, to a method for manufacturing a display panel, a display panel, and a display device. Background Art

[0002] Organic Light-Emitting Diode (OLED) devices are widely used in the display field due to their characteristics of self-luminescence, high brightness, high contrast, fast response speed, wide viewing angle and simple structure.

[0003] OLED devices generate heat during the light-emitting process, which will deteriorate the lifespan and light-emitting efficiency of the OLED devices. In order to solve this problem, the related art discloses a technical solution of setting a heat-absorbing layer between the light-emitting layer and the cathode of the OLED device. However, this solution will further reduce the light-emitting efficiency and light extraction efficiency of the display panel, affecting the overall brightness and lifespan of the display panel. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method for preparing a display panel, a display panel and a display device, so as to solve the technical problem in the related art that when a heat absorption layer is provided, the luminous efficiency and light extraction efficiency of the display panel are reduced, thereby affecting the overall brightness and life of the display panel.

[0005] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0006] A first aspect of the present disclosure provides a display panel, comprising a substrate, a pixel definition layer, a first electrode layer, a light-emitting device layer, a second electrode layer, a heat absorption layer and a packaging layer stacked in sequence on the substrate, the pixel definition layer comprising a plurality of pixel definition structures and a plurality of pixel openings, any of the pixel openings being located between adjacent pixel definition structures, the first electrode layer being disposed in the pixel openings, and an orthographic projection of the heat absorption layer on the substrate not overlapping with an orthographic projection of the pixel opening on the substrate.

[0007] Optionally, the cross-section of the pixel opening is an inverted trapezoid, and the pixel definition structure includes a first surface away from the substrate and a second surface close to the substrate in a direction perpendicular to the substrate, the area of ​​the first surface is smaller than the area of ​​the second surface, and the orthographic projection of the first surface on the substrate covers the orthographic projection of the heat absorption layer on the substrate.

[0008] Optionally, the encapsulation layer includes a first inorganic encapsulation layer, an organic encapsulation layer and a second inorganic encapsulation layer stacked in sequence in a direction away from the substrate, and the heat absorption layer is arranged between the second electrode layer and the first inorganic encapsulation layer or between the first inorganic encapsulation layer and the organic encapsulation layer.

[0009] Optionally, when the heat absorption layer is disposed between the second electrode layer and the first inorganic encapsulation layer, the thickness of the heat absorption layer is less than the thickness of the first inorganic encapsulation layer, and the thickness of the heat absorption layer ranges from 0.5 micrometers to 1.5 micrometers.

[0010] Optionally, when the heat absorption layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer, the thickness of the heat absorption layer is less than the thickness of the organic encapsulation layer, and the thickness of the heat absorption layer ranges from 1 micrometer to 5 micrometers.

[0011] Optionally, the specific heat capacity of the heat absorption layer is greater than the specific heat capacity of the second electrode layer and the packaging layer.

[0012] Optionally, the material of the heat absorption layer is one or more of calcium fluoride, aluminum, magnesium, silicon, boron and beryllium oxide.

[0013] Optionally, the display panel also includes a color film layer or a polarizer arranged on the side of the encapsulation layer away from the substrate, the color film layer includes a plurality of black matrices and a color filter layer arranged between the black matrices, and the orthographic projection of the black matrix on the substrate overlaps with the orthographic projection of the pixel definition structure on the substrate.

[0014] A second aspect of the present disclosure provides a method for preparing a display panel, comprising the following steps:

[0015] Providing a substrate, on which a pixel definition layer, a first electrode layer, a light-emitting device layer and a second electrode layer are sequentially formed, wherein the pixel definition layer comprises a plurality of pixel definition structures and a plurality of pixel openings, any of the pixel openings being located between adjacent pixel definition structures, and the first electrode layer being disposed within the pixel openings;

[0016] A heat absorption layer and a packaging layer are sequentially formed on the second electrode layer, and an orthographic projection of the heat absorption layer on the substrate does not overlap with an orthographic projection of the pixel opening on the substrate.

[0017] A third aspect of the present disclosure provides a display device, comprising the display panel as described above.

[0018] The beneficial effects of the present disclosure are as follows:

[0019] The display panel of the embodiment of the present disclosure is provided with a heat absorption layer on the side of the cathode layer away from the substrate, and the orthographic projection of the heat absorption layer on the substrate does not overlap with the orthographic projection of the pixel opening on the substrate. With such a configuration, on the one hand, the heat absorption layer can absorb the heat generated by the light-emitting device layer during the light-emitting process, reduce the temperature of the light-emitting device layer, alleviate the phenomenon that the light-emitting material in the light-emitting device layer is decomposed by heat and causes the light-emitting efficiency to decrease, and improve the service life of the display panel. On the other hand, since the heat absorption layer is provided on the outside of the sub-pixel, it can avoid the heat absorption layer from having an adverse effect on the transmission of carriers and the recombination of excitons in the light-emitting device layer. In addition, the heat absorption layer does not overlap with the light-emitting area of ​​the sub-pixel, so the heat absorption layer will not affect the light transmittance of the sub-pixel, nor will it affect the light extraction efficiency of the display panel. Therefore, the display panel of the embodiment of the present disclosure can alleviate the decomposition of the light-emitting material by heat without affecting the light-emitting efficiency and light extraction efficiency of the light-emitting device layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The specific implementation methods of the present disclosure are further described in detail below with reference to the accompanying drawings.

[0021] Figure 1 It is a schematic diagram of the film layer structure of a display panel in the related art;

[0022] Figure 2 A schematic diagram of the film layer structure of a display panel provided in an embodiment of the present disclosure;

[0023] Figure 3 A schematic diagram of a film structure when a heat absorption layer provided in an embodiment of the present disclosure is disposed between a first inorganic encapsulation layer and an organic encapsulation layer;

[0024] Figure 4 A schematic diagram of the film structure of the light-emitting device layer provided in an embodiment of the present disclosure;

[0025] Figure 5 A flow chart of a method for preparing a display panel provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0027] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] Please refer to Figure 1 , Figure 1 is a schematic diagram of the film structure of an OLED display panel in the related art, such as Figure 1 As shown, in the related art, the display panel includes a substrate 210, a driving circuit layer 220, a light-emitting functional layer and an encapsulation layer 270 sequentially stacked on the substrate 210, and the light-emitting functional layer further includes a pixel definition layer 230, an anode layer 240, a light-emitting material layer 250 and a cathode layer 260. The light-emitting material layer 250 generates heat during the light-emitting process, and the heat causes the light-emitting material in the light-emitting material layer 250 to degrade, thereby causing the light-emitting efficiency of the display device to decay, affecting the life and performance of the display device.

[0029] In order to solve this technical problem, the related art discloses a technical solution of setting a whole layer of heat absorption layer 280 between the light-emitting material layer 250 and the cathode layer 260. However, the applicant has found through research that this technical solution has the following disadvantages: (1) When the heat absorption layer 280 is set below the cathode layer 260, since the heat absorption layer 280 itself has a certain thickness, the addition of a layer of heat absorption layer 280 will affect the transmission of carriers in the light-emitting material layer 250, thereby affecting the exciton recombination and reducing the luminescence efficiency; (2) When the heat absorption layer 280 is set below the cathode layer 260, the light generated by the light-emitting material layer 250 needs to penetrate the heat absorption layer 280 and be emitted from the light-emitting side of the display panel. The addition of a layer of heat absorption layer 280 will reduce the light transmittance, thereby reducing the light extraction efficiency. Among them, the luminous efficiency and light extraction efficiency jointly affect the overall brightness performance of the display panel. When a heat absorption layer is set under the cathode layer, although the heat absorption layer can absorb part of the heat generated during the luminescence process and alleviate the phenomenon that the luminescent material is thermally degraded and the luminescent efficiency is reduced, the newly added heat absorption layer will affect the transmission of carriers in the luminescent material layer on the one hand, thereby affecting the exciton recombination and reducing the luminous efficiency. On the other hand, it will also reduce the light transmittance, thereby reducing the light extraction efficiency. Therefore, this solution will also reduce the overall brightness of the display panel and affect the service life of the display panel.

[0030] In order to solve the above technical problems, the present disclosure provides a display panel. Figure 2 , Figure 2 A schematic diagram of the film structure of a display panel provided in an embodiment of the present disclosure, such as Figure 2 As shown, the display panel 10 includes a substrate 100, a pixel definition layer 110, a first electrode layer 120, a light-emitting device layer 130, a second electrode layer 140, a heat absorption layer 150 and an encapsulation layer 160 sequentially stacked on the substrate 100, the pixel definition layer 110 includes a plurality of pixel definition structures 1110 and a plurality of pixel openings 1120, any of the pixel openings 1120 is located between adjacent pixel definition structures 1110, the first electrode layer 120 is arranged in the pixel opening 1120, and the orthographic projection of the heat absorption layer 150 on the substrate 100 does not overlap with the orthographic projection of the pixel opening 1120 on the substrate 100.

[0031] The substrate 100 may be a flexible substrate made of materials such as polyimide (PI), polyethylene naphthalate (PEN), and thermoplastic polyester (PET), or a rigid substrate made of materials such as glass and quartz. The display panel 10 may also include a barrier layer and a buffer layer on the substrate 100. The barrier layer and the buffer layer may be formed on the entire surface of the substrate 100. For example, the barrier layer may be made of inorganic insulating materials such as silicon oxide, silicon nitride, or silicon oxynitride. The barrier layer is beneficial to preventing water and oxygen from entering the light-emitting device layer 130 formed later from the bottom. The buffer layer may also be made of inorganic insulating materials such as silicon oxide, silicon nitride, or silicon oxynitride. The buffer layer is beneficial to the quality of subsequent material deposition.

[0032] In the embodiment of the present disclosure, the pixel definition layer 110, the first electrode layer 120, the light emitting device layer 130 and the second electrode layer 140 constitute a plurality of light emitting sub-pixels of the display surface. Exemplarily, the first electrode layer 120 is an anode layer, the second electrode layer 140 is a cathode layer, the first electrode layer 120 includes a plurality of anodes, each of which is disposed in a pixel opening 1120, and the anode is, for example, a metal oxide such as ITO, IZO or a metal such as Ag, Al, Mo or an alloy thereof, and the first electrode layer 120 can be formed by an etching process. The light-emitting device layer 130 is disposed on the anode exposed by the pixel opening 1120. For any pixel opening 1120, the anode disposed therein, the light-emitting device layer 130, and the cathode layer located above the light-emitting device layer 130 form a sub-pixel, wherein the light-emitting device layers 130 of sub-pixels of different colors are different. For example, the red sub-pixel includes a red light-emitting device layer, the green sub-pixel includes a green light-emitting device layer, and the blue sub-pixel includes a blue light-emitting device layer. It can be understood that the light-emitting device layer 130 is not limited to the red light-emitting device layer, the green light-emitting device layer, and the blue light-emitting device layer, and it can also be other colors. The second electrode layer 140 can be formed on the entire surface above the light-emitting device layer 130, covering the light-emitting device layer 130 and the pixel definition layer 110. The material of the second electrode layer 140 can include metals such as Mg, Ca, Li or Al or their alloys, or metal oxides such as IZO and ZTO, or organic materials with conductive properties such as PEDOT / PSS (poly 3,4-ethylenedioxythiophene / polystyrene sulfonate).

[0033] In the disclosed embodiment, the pixel definition layer 110 includes a plurality of pixel definition structures 1110 and a plurality of pixel openings 1120, wherein adjacent pixel definition structures 1110 define the pixel openings 1120, which can also be understood as the pixel definition layer 110 having a plurality of pixel openings 1120, and the pixel definition layer 110 around the pixel openings 1120 is the pixel definition structure 1110. In specific implementation, the pixel definition layer 110 can be formed by a patterning process, and is arranged around the anode. Exemplarily, the material of the pixel definition layer 110 can include organic insulating materials such as negative photoresist, polyimide, and epoxy resin.

[0034] In the embodiment of the present disclosure, the heat absorption layer 150 is located outside the second electrode layer 140, that is, the side of the second electrode layer 140 away from the substrate 100. In this way, the original structure of the light-emitting functional layer can be left unchanged. Compared with the structure in the related art where the heat absorption layer is disposed between the light-emitting device layer and the cathode, the heat absorption layer 150 in the embodiment of the present disclosure will not have adverse effects on the transmission of carriers and the recombination of excitons in the light-emitting device layer 130. In addition, the orthographic projection of the heat absorption layer 150 on the substrate 100 does not overlap with the orthographic projection of the pixel opening 1120 on the substrate 100. Since the anode and the light-emitting device layer 130 are disposed in the pixel opening 1120, for any sub-pixel, its light-emitting area is the area where the pixel opening 1120 is located. Therefore, the orthographic projections of the heat absorption layer 150 and the pixel opening 1120 on the substrate 100 do not overlap, which can also be understood as the heat absorption layer 150 and the light-emitting area of ​​the sub-pixel do not overlap. In this way, the heat absorption layer 150 will not affect the light transmittance of the sub-pixel, nor will it affect the light extraction efficiency of the display panel. In addition, the heat absorption layer 150 can also absorb the heat generated by the light-emitting device layer 130 during the light-emitting process, reduce the temperature of the light-emitting device layer 130, alleviate the phenomenon that the light-emitting material in the light-emitting device layer 130 is decomposed by heat and causes the light-emitting efficiency to decrease, and improve the service life of the display panel.

[0035] Compared with the related art, the display panel of the embodiment of the present disclosure sets a heat absorption layer on the side of the cathode layer away from the substrate, and the orthographic projection of the heat absorption layer on the substrate does not overlap with the orthographic projection of the pixel opening on the substrate. With such a setting, on the one hand, the heat absorption layer can absorb the heat generated by the light-emitting device layer during the light-emitting process, reduce the temperature of the light-emitting device layer, alleviate the phenomenon that the light-emitting material in the light-emitting device layer is decomposed by heat and causes the light-emitting efficiency to decrease, thereby improving the service life of the display panel. On the other hand, since the heat absorption layer is set on the outside of the sub-pixel, it can avoid the heat absorption layer from having an adverse effect on the transmission of carriers and the recombination of excitons in the light-emitting device layer. In addition, the heat absorption layer does not overlap with the light-emitting area of ​​the sub-pixel, so the heat absorption layer will not affect the light transmittance of the sub-pixel, nor will it affect the light extraction efficiency of the display panel. Therefore, the display panel of the embodiment of the present disclosure can alleviate the thermal decomposition of the light-emitting material without affecting the light-emitting efficiency and light extraction efficiency of the light-emitting device layer, thereby improving the service life of the display panel.

[0036] In a possible implementation, the cross-section of the pixel opening 1120 is an inverted trapezoid, and the pixel definition structure 1110 includes a first surface 1110a away from the substrate 100 in a direction perpendicular to the substrate 100 and a second surface 1110b close to the substrate 100, the area of ​​the first surface 1110a is smaller than the area of ​​the second surface 1110b, and the orthographic projection of the first surface 1110a on the substrate 100 covers the orthographic projection of the heat absorption layer 150 on the substrate 100.

[0037] In the embodiment of the present disclosure, the cross section of the pixel opening 1120 is an inverted trapezoid that is wide at the top and narrow at the bottom. Here, the top and the bottom refer to the distance relative to the substrate 100, and the larger the distance, the higher the distance, and the smaller the distance, the lower the distance. For example, the pixel opening 1120 includes an upper surface 1120a away from the substrate 100 and a lower surface 1120 close to the substrate 100, wherein the area of ​​the upper surface 1120a is greater than the area of ​​the lower surface 1120b, and the orthographic projection of the upper surface 1120a on the substrate 100 completely covers the orthographic projection of the lower surface 1120b on the substrate 100. Correspondingly, the cross section of the pixel definition structure 1110 in the display area is a trapezoid that is narrow at the top and wide at the bottom, that is, the area of ​​the first surface 1110a of the pixel definition structure 1110 away from the substrate 100 is smaller than the area of ​​the second surface 1110b close to the substrate 100, and the orthographic projection of the first surface 1110a on the substrate 100 completely falls within the orthographic projection of the second surface 1110b on the substrate 100.

[0038] The orthographic projection of the heat absorption layer 150 on the substrate 100 does not overlap with the orthographic projection of the pixel opening 1120 on the substrate 100. In a specific implementation, the heat absorption layer 150 is disposed on the pixel definition structure 1110, and the orthographic projection of the heat absorption layer 150 on the substrate 100 falls within the orthographic projection of the first surface 1110a of the pixel definition structure 1110 on the substrate 100. At this time, the area where the heat absorption layer 150 is located does not overlap with the area where the pixel opening 1120 is located, which can avoid the heat absorption layer 150 from causing adverse effects on the light extraction efficiency of the sub-pixel.

[0039] The orthographic projection of the first surface 1110a on the substrate 100 covers the orthographic projection of the heat absorption layer 150 on the substrate 100, which includes two situations: (1) the area of ​​the orthographic projection of the first surface 1110a on the substrate 100 is the same as the area of ​​the orthographic projection of the heat absorption layer 150 on the substrate 100, in which case the orthographic projection of the first surface 1110a on the substrate 100 and the orthographic projection of the heat absorption layer 150 on the substrate 100 completely overlap; (2) the area of ​​the orthographic projection of the first surface 1110a on the substrate 100 is larger than the area of ​​the orthographic projection of the heat absorption layer 150 on the substrate 100, in which case the orthographic projection of the first surface 1110a on the substrate 100 completely covers and partially exceeds the orthographic projection of the heat absorption layer 150 on the substrate 100.

[0040] Optionally, the orthographic projection of the first surface 1110a on the substrate 100 completely overlaps with the orthographic projection of the heat absorption layer 150 on the substrate 100. In this case, the heat absorption layer 150 has the largest area and the best heat absorption effect without overlapping with the light-emitting area.

[0041] In one possible implementation, the encapsulation layer 160 includes a first inorganic encapsulation layer 1610, an organic encapsulation layer 1620, and a second inorganic encapsulation layer 1630 stacked in sequence in a direction away from the substrate 100, and the heat absorption layer 150 is arranged between the second electrode layer 140 and the first inorganic encapsulation layer 1610 or between the first inorganic encapsulation layer 1610 and the organic encapsulation layer 1620.

[0042] Exemplarily, the first inorganic encapsulation layer 1610 and the second inorganic encapsulation layer 1630 are formed by deposition or the like, and the organic encapsulation layer 1620 is formed by inkjet printing. For example, the first inorganic encapsulation layer 1610 and the second inorganic encapsulation layer 1630 can be formed by depositing inorganic materials such as silicon nitride, silicon oxide, and silicon oxynitride, and the organic encapsulation layer 1620 can be formed by inkjet printing organic materials such as polyimide (PI) and epoxy resin. The first inorganic encapsulation layer 1610, the organic encapsulation layer 1620, and the second inorganic encapsulation layer 1630 form a composite encapsulation layer, which can form multiple protections for the functional structure of the display panel and has a better encapsulation effect.

[0043] The thickness of the first inorganic encapsulation layer 1610 is usually 0.5 microns to 1.5 microns, the thickness of the second inorganic encapsulation layer 1630 is also usually 0.5 microns to 1.5 microns, and the thickness of the organic encapsulation layer 1620 is relatively large, usually 1 micron to 5 microns. Exemplarily, the thickness of the first inorganic encapsulation layer 1610 and the second inorganic encapsulation layer 1630 are both 1.5 microns, and the thickness of the organic encapsulation layer 1620 is 5 microns. At this time, the thickness of the entire encapsulation layer 160 is 8 microns.

[0044] In the embodiment of the present disclosure, the heat absorption layer 150 is disposed above the second electrode layer 140 and at least below the organic encapsulation layer 1620, and the thickness of the heat absorption layer 150 is less than the thickness of the encapsulation layer located above it. For example: when the heat absorption layer 150 is disposed above the second electrode layer 140 and below the first inorganic encapsulation layer 1610, the thickness of the heat absorption layer 150 is less than the thickness of the first inorganic encapsulation layer 1610; when the heat absorption layer 150 is disposed above the first inorganic encapsulation layer 1610 and below the organic encapsulation layer 1620, the thickness of the heat absorption layer 150 is less than the thickness of the organic encapsulation layer 1620. Such a configuration can ensure the encapsulation effect of the encapsulation film layer (such as the first inorganic encapsulation layer 1610 or the organic encapsulation layer 1620) formed above the heat absorption layer 150, and form an encapsulation film layer with a smooth surface.

[0045] Optional, such as Figure 2 As shown, when the heat absorption layer 150 is disposed between the second electrode layer 140 and the first inorganic encapsulation layer 1610, the thickness of the heat absorption layer 150 is less than the thickness of the first inorganic encapsulation layer 1610, and the thickness of the heat absorption layer ranges from 0.5 micrometers to 1.5 micrometers. The thickness range of 0.5 micrometers to 1.5 micrometers indicates that the thickness of the heat absorption layer 150 is greater than 0.5 micrometers and less than 1.5 micrometers, for example, the thickness of the heat absorption layer 150 is 0.6 micrometers, 1 micrometer, 1.4 micrometers, etc.

[0046] Optional, such as Figure 3 As shown, when the heat absorption layer 150 is disposed between the first inorganic encapsulation layer 1610 and the organic encapsulation layer 1620, the thickness of the heat absorption layer 150 is less than the thickness of the organic encapsulation layer 1620, and the thickness of the heat absorption layer 150 ranges from 1 micron to 5 microns. The thickness range of 1 micron to 5 microns indicates that the thickness of the heat absorption layer 150 is greater than 1 micron and less than 5 microns, for example, the thickness of the heat absorption layer 150 is 1.5 microns, 2 microns, 3 microns, 4 microns, 4.5 microns, etc.

[0047] In a possible implementation, the specific heat capacity of the heat absorption layer 150 is greater than the specific heat capacity of the second electrode layer 140, and the specific heat capacity of the heat absorption layer 150 is greater than the specific heat capacity of the encapsulation layer 160. The specific heat capacity of the heat absorption layer 150 is greater than the specific heat capacity of the encapsulation layer 160 can be understood as: the specific heat capacity of the heat absorption layer 150 is greater than the specific heat capacity of the first inorganic encapsulation layer 1610, the organic encapsulation layer 1620 and the second inorganic encapsulation layer 1630.

[0048] Among them, the specific heat capacity (Specific Heat Capacity) is also called specific heat capacity, or specific heat for short. It is the heat capacity of a substance per unit mass, that is, the heat absorbed or released when a unit mass of an object changes unit temperature. Its unit can be expressed as joule per gram Celsius, that is, J / (g·℃) or joule per gram Kelvin, that is, J / (kg·K). In thermodynamic calculations, the two units of J / (kg·℃) or J / (kg·K) can be used as needed. Since the values ​​of each change of 1℃ and each change of 1K are numerically equal, in actual calculations, these two units can be used interchangeably without causing changes in the calculation results. Under the same mass, a substance with a large specific heat capacity can absorb more heat and the temperature rises less, while a substance with a small specific heat capacity has a higher temperature rise when absorbing the same amount of heat. In the disclosed embodiment, the specific heat capacity of the heat absorption layer 150 is greater than the specific heat capacity of the second electrode layer 140 located thereunder, and greater than the specific heat capacity of the encapsulation layer 160. Such a setting has the following advantages:

[0049] (1) The heat absorption layer 150 has a large specific heat capacity, which can absorb and store more heat, thereby effectively reducing the damage to the light-emitting material caused by the heat generated during the light-emitting process of the light-emitting device layer 130;

[0050] (2) Protecting the second electrode layer 140. Specifically, the second electrode layer 140, i.e., the cathode layer, is an electron injection layer, and its performance has an important influence on the luminous efficiency. By setting the specific heat capacity of the heat absorption layer 150 to be greater than the specific heat capacity of the second electrode layer 140, the damage of heat to the cathode can be effectively reduced, thereby extending its service life.

[0051] (3) Protecting the encapsulation layer 160. The main function of the encapsulation layer 160 is to protect the internal film layer from erosion by the external environment. By setting the specific heat capacity of the heat absorption layer 150 to be greater than the specific heat capacity of the encapsulation layer 160, the heat transfer to the encapsulation layer 160 can be reduced, thereby reducing the risk of the encapsulation layer 160 being damaged by high temperature.

[0052] It can be seen that the heat absorption layer 150 in the embodiment of the present disclosure can, on the one hand, reduce the performance degradation of the light-emitting material in the light-emitting device layer 130 caused by overheating, thereby maintaining a high light-emitting efficiency and extending the service life; on the other hand, by protecting the adjacent film layers from high temperature damage, it can improve the stability of the panel and extend the service life of the display panel.

[0053] Optionally, the material of the second electrode layer 140 is silver (Ag), and the specific heat capacity of silver is about 0.24 J / (g·K). Since the specific heat capacity of silver is relatively low, its temperature rise is relatively high when absorbing the same amount of heat.

[0054] Optionally, the material of the heat absorption layer 150 is one or more of calcium fluoride (CaF2), aluminum (Al), magnesium (Mg), silicon (Si), boron (B) and beryllium oxide (BeO). Among them, the specific heat capacity of calcium fluoride is about 0.839 J / (g·℃), the specific heat capacity of aluminum is about 0.897 J / (g·℃), the specific heat capacity of magnesium is about 1.020 J / (g·℃), the specific heat capacity of silicon is about 0.700 J / (g·℃), the specific heat capacity of boron is about 1.025 J / (g·℃), and the specific heat capacity of beryllium oxide is about 2.013 J / (g·℃). It can be understood that the material of the heat absorption layer 150 in the embodiment of the present disclosure includes but is not limited to the above examples. The material of the heat absorption layer 150 can also be other materials with high specific heat capacity, such as materials with a specific heat capacity higher than 0.7 J / (g·℃).

[0055] In a possible implementation, the display panel 10 further includes a color filter layer 170 or a polarizer disposed on a side of the encapsulation layer 160 away from the substrate 100, the color filter layer 170 includes a plurality of black matrices 1710 and a color filter layer 1720 disposed between the black matrices 1710, and the color filter layer 1720 is disposed in one-to-one correspondence with the pixel opening 1120. Exemplarily, the orthographic projection of the black matrix 1710 on the substrate 100 overlaps with the orthographic projection of the pixel definition structure 1110 on the substrate 100, and the orthographic projection of the color filter layer 1720 on the substrate 100 overlaps with the orthographic projection of the upper surface of the pixel opening 1120 on the substrate 100. Among them, the color filter layer 170 or the polarizer can reduce the reflection of the external ambient light, thereby improving the display effect of the display panel.

[0056] Optionally, the color filter layer 1720 is a blue filter layer, a red filter layer or a green filter layer. The color of the color filter layer 1720 is consistent with the color of the light emitted by the corresponding sub-pixel light-emitting device layer 130. For example, if the light-emitting device layer 130 of the sub-pixel at the corresponding position emits blue light, the color filter layer 1720 is a blue filter layer, if the light-emitting device layer 130 of the sub-pixel at the corresponding position emits red light, the color filter layer 1720 is a red filter layer, and if the light-emitting device layer 130 of the sub-pixel at the corresponding position emits green light, the color filter layer 1720 is a green filter layer.

[0057] Optionally, the polarizer is a circular polarizer.

[0058] It can be understood that the color filter layer 170 in the embodiment of the present disclosure is a color filter structure formed by COE (Color filter On Encapsulation) technology, which can replace the polarizer in the related art, and is also called a polarizer-less (POL-less) structure.

[0059] In the disclosed embodiment, since the heat absorption layer 150 and the light-emitting area of ​​the sub-pixel, that is, the light-emitting path, have no intersection, the heat absorption layer 150 has no effect on the light output. Therefore, in addition to the COE structure, the display panel can also adopt the polarizer as described above, that is, the POL (Polarizer) structure.

[0060] Optional, such as Figure 2 As shown, the display panel 10 further includes a driving circuit layer 180 disposed between the substrate 100 and the pixel definition layer 110. The driving circuit layer 180 may also be referred to as a thin film transistor (TFT) layer.

[0061] Exemplarily, the driving circuit layer 180 includes an active layer (Active) formed on the buffer layer by a patterning process, a gate insulating layer (GI) formed on the active layer by deposition or the like, a gate (Gate) of a thin film transistor formed on the gate insulating layer by a patterning process, a dielectric layer (ILD) formed on the gate by deposition or the like, a source-drain metal layer formed on the dielectric layer, and a flat layer (PLN) covering the source-drain metal layer and the exposed dielectric layer, wherein the source-drain metal layer forms the source (Source) and drain (Drain) of the thin film transistor, for example, the source is electrically connected to the active layer through a dielectric layer via. Among them, the active layer can be made of materials such as polysilicon and metal oxides, the gate insulating layer can be made of inorganic insulating materials such as silicon oxide, silicon nitride or silicon oxynitride, and the dielectric layer can be made of inorganic insulating materials such as silicon oxide, silicon nitride or silicon oxynitride. The gate material includes metals or alloy materials such as aluminum, titanium, and cobalt. The flat layer is, for example, an organic material.

[0062] Optional, such as Figure 4As shown, the light-emitting device layer 130 includes a light-emitting layer (EML), which is a single-layer structure. In other embodiments, the light-emitting device layer 130 may also include an auxiliary light-emitting layer that helps the light-emitting layer emit light, and the auxiliary light-emitting layer includes, for example, a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EIL), a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL) One or more film layers. The light-emitting layer and the auxiliary light-emitting layer are, for example, organic material layers.

[0063] The display panel in the implementation of the present disclosure may be an organic light-emitting diode (OLED) display panel. It is understandable that the display panel may be set to other types according to actual needs, for example, the display panel may also be a quantum dot light emitting diode (QLED) display panel or a micro light emitting diode (Micro LED) display panel.

[0064] Based on the same inventive concept, the second aspect of the present disclosure provides a method for preparing a display panel, such as Figure 5 As shown, it includes the following steps:

[0065] Step S101, providing a substrate, and sequentially forming a pixel definition layer, a first electrode layer, a light-emitting device layer and a second electrode layer on the substrate, wherein the pixel definition layer includes a plurality of pixel definition structures and a plurality of pixel openings, any of the pixel openings being located between adjacent pixel definition structures, and the first electrode layer being disposed in the pixel openings.

[0066] Step S102 , forming a heat absorption layer and a packaging layer in sequence on the second electrode layer, wherein an orthographic projection of the heat absorption layer on the substrate does not overlap with an orthographic projection of the pixel opening on the substrate.

[0067] Optionally, a heat absorption layer is formed on the second electrode layer by a first process, and the first process includes but is not limited to a vapor deposition process, inkjet printing, an evaporation process or a photolithography process. Since the vapor deposition process, inkjet printing, an evaporation process or a photolithography process are conventional processes in the art, the embodiments of the present disclosure do not describe them in detail. The specific process can be selected based on factors such as the properties of the heat absorption layer material, the thickness of the heat absorption layer, the pattern accuracy and the cost.

[0068] Optionally, the method for preparing the display panel further includes: forming a color filter layer on the side of the encapsulation layer away from the substrate, the color filter layer including a plurality of black matrices and a color filter layer arranged between the black matrices. The specific implementation mainly includes two steps: (1) forming a black matrix layer on the side of the encapsulation layer away from the substrate, and then etching the black matrix layer through an etching process to form a plurality of black matrices, wherein the orthographic projection of the black matrix on the substrate overlaps with the orthographic projection of the pixel definition structure on the substrate, which can separate color filter layers of different colors, prevent color mixing, and improve the contrast and clarity of the display. (2) forming red, green, and blue color filter layers on the encapsulation layer by evaporation or deposition of transparent color film technology.

[0069] Based on the same inventive concept, the third aspect of the present disclosure provides a display device, including the display panel as described above. Exemplarily, the display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, a navigator, etc., which is not limited in this embodiment.

[0070] Obviously, the above embodiments of the present disclosure are merely examples for clearly illustrating the present disclosure, and are not limitations on the implementation methods of the present disclosure. For ordinary technicians in this field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present disclosure are still within the protection scope of the present disclosure.

Claims

1. A display panel, characterized in that: The invention comprises a substrate, a pixel definition layer, a first electrode layer, a light-emitting device layer, a second electrode layer, a heat absorption layer and a packaging layer which are sequentially stacked on the substrate, wherein the pixel definition layer comprises a plurality of pixel definition structures and a plurality of pixel openings, any of the pixel openings is located between adjacent pixel definition structures, the first electrode layer is arranged in the pixel openings, and the orthographic projection of the heat absorption layer on the substrate does not overlap with the orthographic projection of the pixel opening on the substrate.

2. The display panel according to claim 1, characterized in that: The cross-section of the pixel opening is in an inverted trapezoid. The pixel definition structure includes a first surface away from the substrate and a second surface close to the substrate in a direction perpendicular to the substrate. The area of ​​the first surface is smaller than the area of ​​the second surface. The orthographic projection of the first surface on the substrate covers the orthographic projection of the heat absorption layer on the substrate.

3. The display panel according to claim 1, characterized in that: The encapsulation layer includes a first inorganic encapsulation layer, an organic encapsulation layer and a second inorganic encapsulation layer stacked in sequence in a direction away from the substrate, and the heat absorption layer is arranged between the second electrode layer and the first inorganic encapsulation layer or between the first inorganic encapsulation layer and the organic encapsulation layer.

4. The display panel according to claim 3, characterized in that: When the heat absorption layer is disposed between the second electrode layer and the first inorganic encapsulation layer, the thickness of the heat absorption layer is less than the thickness of the first inorganic encapsulation layer, and the thickness of the heat absorption layer ranges from 0.5 micrometers to 1.5 micrometers.

5. The display panel according to claim 3, characterized in that: When the heat absorption layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer, the thickness of the heat absorption layer is less than the thickness of the organic encapsulation layer, and the thickness of the heat absorption layer ranges from 1 micrometer to 5 micrometers.

6. The display panel according to claim 1, characterized in that: The specific heat capacity of the heat absorption layer is greater than the specific heat capacity of the second electrode layer and the packaging layer.

7. The display panel according to claim 6, characterized in that: The material of the heat absorption layer is one or more of calcium fluoride, aluminum, magnesium, silicon, boron and beryllium oxide.

8. The display panel according to claim 1, characterized in that: The display panel also includes a color filter layer or a polarizer arranged on the side of the encapsulation layer away from the substrate, the color filter layer includes a plurality of black matrices and a color filter layer arranged between the black matrices, and the orthographic projection of the black matrix on the substrate overlaps with the orthographic projection of the pixel definition structure on the substrate.

9. A method for preparing a display panel, characterized in that: The following steps are involved: Providing a substrate, on which a pixel definition layer, a first electrode layer, a light-emitting device layer and a second electrode layer are sequentially formed, wherein the pixel definition layer comprises a plurality of pixel definition structures and a plurality of pixel openings, any of the pixel openings being located between adjacent pixel definition structures, and the first electrode layer being disposed within the pixel openings; A heat absorption layer and a packaging layer are sequentially formed on the second electrode layer, and an orthographic projection of the heat absorption layer on the substrate does not overlap with an orthographic projection of the pixel opening on the substrate.

10. A display device, characterized in that: Comprising the display panel as claimed in any one of claims 1 to 8.

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