Display panel and preparation method

Abstract

According to the display panel and the preparation method provided by the invention, the light extraction layer formed by the porous graphene is arranged on the light emitting layer, so that the light emitting rate of the light in the light emitting layer can be improved, and meanwhile, the porous graphene structures with different pores have different improvement degrees on the light emitting rate, so that the light emitting efficiency is improved. The pores of the porous graphene corresponding to different light-emitting units are specifically arranged, so that the light-emitting efficiency finally displayed by the light-emitting units with different colors can be unified by combining the improvement of the emitting rate of the porous graphene and the light-emitting efficiency of the light-emitting units; the light-emitting units with different colors are set to be the same in size, and the consistency of the light-emitting efficiency can also be realized, so that the same mask plate can be adopted to realize preparation, and the increase of the cost and the improvement of the preparation difficulty are avoided.

Description

Technical Field

[0001] This invention relates to the field of display panels, and more particularly to a display panel and its manufacturing method. Background Technology

[0002] OLED (Organic Light-Emitting Diode) materials are those whose brightness decreases over time, especially blue light-emitting materials, whose lifespan decays much faster than that of red and green light. Therefore, in current mass-produced OLED display panels, to compensate for the uneven display brightness caused by the decay of blue pixel luminous efficiency, the common approach is to increase the aperture of the blue pixels. For example, in the pixel arrangement of existing OLED display panels, the area of ​​blue pixels is significantly larger than that of red and green pixels. This results in a large difference in the aperture of pixels of different colors. Therefore, when fabricating the light-emitting layer, it is necessary to set different apertures for different color light-emitting units using FMM (Fine Metal Mask), which increases the fabrication cost and difficulty of the light-emitting layer. Summary of the Invention

[0003] The main objective of this invention is to propose a display panel and its manufacturing method, which aims to solve the problem of increased manufacturing costs and difficulties caused by the large difference in aperture ratio of different color pixels in OLED panels in the prior art.

[0004] To achieve the above objectives, the present invention provides a display panel, the display panel comprising: The light-emitting layer includes light-emitting units corresponding to pixels of different colors, wherein the light-emitting units of different colors are of the same size; A light extraction layer, disposed on the light-emitting layer, is composed of porous graphene. The porous graphene on different colored light-emitting units has different structures, and the porous graphene with different structures has different light extraction rates for the corresponding light-emitting units. The actual luminous efficiency of each of the light-emitting units through the corresponding porous graphene is the same. The actual luminous efficiency is obtained by superimposing the unit luminous efficiency of the light-emitting unit with the light extraction rate of the corresponding porous graphene.

[0005] Optionally, the porous graphene located on light-emitting units of different colors has different pore sizes, and the porous graphene with different pore sizes has different light extraction rates for the corresponding light-emitting units.

[0006] Optionally, the display panel further includes: An inorganic protective layer is disposed between the light-emitting layer and the light-extracting layer.

[0007] Optionally, the display panel further includes: A cathode layer is disposed between the light-emitting layer and the inorganic protective layer; Isolation columns are disposed between adjacent light-emitting units; The inorganic protective layer is disconnected at the location of the isolation column, and the cathode layer and the light extraction layer are connected at the location of the isolation column.

[0008] Optionally, the display panel further includes: A first inorganic encapsulation layer is disposed on the light extraction layer.

[0009] To achieve the above objectives, the present invention also provides a method for manufacturing a display panel, the method comprising: A light-emitting layer is prepared, the light-emitting layer comprising light-emitting units corresponding to pixels of different colors, wherein the light-emitting units of different colors are of the same size; Determine the unit luminous efficiency of each of the light-emitting units; Determine the target structure of porous graphene corresponding to the luminous efficiency of the unit; A light extraction layer is obtained by preparing porous graphene on the light-emitting layer. The target structures of the porous graphene located on light-emitting units of different colors are different. The light extraction rates of the porous graphene with different structures to the corresponding light-emitting units are different. The actual luminous efficiency of each light-emitting unit emitting light through the corresponding porous graphene is the same. The actual luminous efficiency is obtained by superimposing the unit luminous efficiency of the light-emitting unit with the light extraction rate of the corresponding porous graphene.

[0010] Optionally, the fabrication of the light-emitting layer includes: Different colored light-emitting units are vapor-deposited using a photomask. The light-emitting units of different colors all use the same mask structure.

[0011] Optionally, determining the target structure of the porous graphene corresponding to the unit luminescence efficiency includes: For each color of the light-emitting unit, the wavelength range corresponding to that color is determined; Match the pore size range to the wavelength range; Obtain the target luminous efficiency and the unit luminous efficiency of the light-emitting unit; Within the pore range, a target pore is determined that corresponds to the light extraction rate that, in conjunction with the unit luminous efficiency, can yield the target luminous efficiency.

[0012] Optionally, the step of preparing a porous graphene layer on the light-emitting layer to obtain a light extraction layer includes: An inorganic protective layer is prepared on the light-emitting layer; The porous graphene was prepared on the inorganic protective layer to obtain the light extraction layer.

[0013] Optionally, the step of preparing an inorganic protective layer on the light-emitting layer includes: A cathode layer is prepared on the light-emitting layer; The inorganic protective layer is prepared on the cathode layer; The portion of the inorganic protective layer located at the isolation column position is removed.

[0014] This invention proposes a display panel and its fabrication method. The display panel includes: a light-emitting layer comprising light-emitting units corresponding to different color pixels, wherein the light-emitting units of different colors are of the same size; a light extraction layer disposed on the light-emitting layer and composed of porous graphene, wherein the porous graphene on the light-emitting units of different colors has different structures, and the porous graphene with different structures has different light extraction rates for the corresponding light-emitting units; the actual luminous efficiency of each light-emitting unit emitting light through the corresponding porous graphene is the same, and the actual luminous efficiency is obtained by superimposing the unit luminous efficiency of the light-emitting unit with the light extraction rate of the corresponding porous graphene. By setting a light extraction layer composed of porous graphene on the light-emitting layer, the light emissivity in the light-emitting layer can be improved. At the same time, the degree of improvement in emissivity varies among porous graphene structures with different pore sizes. Therefore, by specifically setting the pore size of the porous graphene corresponding to different light-emitting units, the luminous efficiency of different colored light-emitting units can be unified by combining the improved emissivity of porous graphene with the luminous efficiency of the light-emitting units themselves. In this case, setting the light-emitting units of different colors to the same size can also achieve consistency in luminous efficiency. Therefore, the same mask can be used for fabrication, avoiding increased costs and fabrication difficulty. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the layered structure of the display panel of the present invention; Figure 2This is a comparison chart of the sub-pixel aperture ratio in this invention and the prior art; Figure 3 This is a comparison diagram of the photomask in the present invention and the prior art; Figure 4 This is a schematic diagram of the stacked encapsulation consisting of the light extraction layer and the first inorganic encapsulation layer in this invention; Figure 5 This is a schematic flowchart of the first embodiment of the display panel manufacturing method of the present invention.

[0018] Explanation of icon numbers: Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0020] This invention provides a display panel, see below. Figure 1 , Figure 1 This is a schematic diagram of the hierarchical structure of the display panel of the present invention; the display panel includes: The light-emitting layer 300 includes light-emitting units 310 corresponding to pixels of different colors, wherein the light-emitting units 310 of different colors are of the same size; A light extraction layer 600 is disposed on the light-emitting layer 300 and is composed of porous graphene. The porous graphene on the light-emitting units 310 of different colors has different structures, and the porous graphene with different structures has different light extraction rates for the corresponding light-emitting units 310. The actual luminous efficiency of each of the light-emitting units 310 through the corresponding porous graphene is the same. The actual luminous efficiency is obtained by superimposing the unit luminous efficiency of the light-emitting unit 310 with the light extraction rate of the corresponding porous graphene.

[0021] The light-emitting layer 300 is a functional layer in the OLED display panel that is composed of organic electroluminescent materials to enable pixel light emission.

[0022] The light-emitting unit 310 is the smallest independent part of the light-emitting layer 300 that emits light; for example, the light-emitting unit 310 can be a red light-emitting unit 310 within a pixel.

[0023] It is understandable that the light-emitting layer 300 specifically contains light-emitting units 310 of three colors: red (R), green (G), and blue (B).

[0024] See Figure 2 , 3 In existing technologies, the sizes of red, green, and blue sub-pixels in OLED display panels are set differently. Here, size refers to aperture ratio. For example, the aperture size of the red sub-pixel is a1×b1, the aperture size of the green sub-pixel is a2×b2, and the aperture size of the blue sub-pixel is a3×b3. That is, the aperture ratio of the light-emitting unit 310 of different colors is different. For example, in a typical diamond arrangement structure, the aperture ratio of the blue sub-pixel can even be twice that of the red sub-pixel. Different aperture ratios mean that different photomasks are required for different light-emitting units 310 when evaporating the light-emitting layer 300. For example, a photomask FMM-R matching a1×b1 is required for the fabrication of the red light-emitting unit 310, a photomask FMM-G matching a2×b2 is required for the fabrication of the green light-emitting unit 310, and a photomask FMM-B matching a3×b3 is required for the fabrication of the blue light-emitting unit 310.

[0025] In this embodiment, by setting the size of the light-emitting units 310 of different colors to be the same, such as the opening size of the red, green, and blue light-emitting units 310 being a×b, the light-emitting units 310 of different colors can be fabricated using the same mask template FMM-R / G / B, thereby saving the cost of the mask and ensuring the consistency of the fabrication effect of the light-emitting units 310 of different colors. On this basis, due to the uniform aperture ratio of the light-emitting units 310, the light-emitting units 310 of different colors do not have special arrangement. Therefore, the sub-pixels in the OLED can be set as a pixel arrangement structure similar to that of an LCD with horizontal and vertical arrays, further reducing the difficulty of the fabrication process.

[0026] The unit luminous efficiency is the luminous efficiency of the light-emitting unit itself.

[0027] After setting the size of the red, green, and blue light-emitting units 310 to be the same, the problem that needs to be addressed is that the three light-emitting units 310 are made of different materials. Different materials have different characteristics. For example, the material used to make the blue light-emitting unit 310 decays faster than the red and green materials. This will result in different luminous efficiencies among the three colors of light-emitting units 310. For example, the luminous efficiency of blue is the lowest. The luminous efficiency of green and red is similar but still has some differences. Therefore, after unifying the size of the light-emitting units 310, it is also necessary to solve the differences in luminous efficiency between the light-emitting units 310 to ensure the accuracy of the display panel.

[0028] In this embodiment, the difference in luminous efficiency between light-emitting units 310 of different colors is eliminated by setting a light extraction layer 600.

[0029] The light extraction layer 600 is a layer structure disposed on the light emitting layer 300 to improve the light output efficiency of the light emitting unit 310 in the light emitting layer 300.

[0030] In this embodiment, the light extraction layer 600 is specifically constructed using porous graphene.

[0031] Porous graphene is formed by laser irradiation to induce photothermal effects and chemical bond breaking and recombination on the material surface. The specific material can be set according to actual needs, such as porous silica nanoparticles or organic materials with phase separation structure.

[0032] The core principle of laser-induced graphene can be summarized into the following key processes: 1. Laser-induced carbonization process: Laser irradiation causes the chemical bonds such as CO and C=O on the material surface to break, and carbon atoms rearrange at high temperature to form an amorphous carbon structure.

[0033] 2. Structural transformation mechanism: Amorphous carbon structures further absorb heat and transform into the typical hexagonal structure of graphene. However, due to the extremely short dynamic rearrangement time of carbon atoms, reaching the femtosecond level, mixed polygonal structures are often formed, such as five-membered rings and seven-membered rings, resulting in a high defect density.

[0034] By adjusting the laser parameters and material type, the number of layers, porosity, and conductivity of the generated porous graphene can be controlled. Laser parameters include pulse width and repetition frequency, and material type includes polymer substrates.

[0035] It is understandable that in an OLED display panel, the light emitted by the light-emitting unit 310 is affected by multiple total internal reflections between the light-emitting layer 300 and the glass substrate or between the glass substrate and the atmosphere, resulting in light loss and the light not being able to escape from the glass, thus causing a problem of low light output.

[0036] By setting a light extraction layer 600 made of porous graphene containing nanoscale pores on the light-emitting layer 300, the light emitted by the light-emitting unit 310 is scattered through the pores in the porous graphene, thereby changing the direction of photon propagation and scattering the light. This greatly avoids the light loss caused by total internal reflection, allowing more light to be released, thereby improving the light extraction rate of the light-emitting unit 310 and improving the overall luminous efficiency.

[0037] It is understandable that the structure of porous graphene is related to the degree to which it improves light extraction efficiency. For example, increasing the porosity of porous graphene can reduce total internal reflection loss more, thereby improving light extraction efficiency. Furthermore, by setting more layers, the number of light scattering events can be set. More layers can achieve more scattering events, thereby further improving light extraction efficiency. At the same time, more scattering will also cause higher scattering loss. Therefore, by combining the setting of multiple types of parameters of the porous graphene structure, it is possible to set the light extraction efficiency of the corresponding light-emitting unit 310.

[0038] The light-emitting units 310 of red, green, and blue can all achieve an increase in light extraction efficiency under the setting of porous graphene. The specific degree of light extraction efficiency improvement of porous graphene is controllable. Therefore, different porous graphene structures are set for light-emitting units 310 of different colors, so that the light extraction efficiency of light-emitting units 310 of different colors is improved to different degrees, thereby offsetting the differences in luminous efficiency between light-emitting units 310 of different colors and achieving uniform luminous efficiency.

[0039] As explained above, the blue light-emitting unit 310 has the lowest luminous efficiency, while the red and green light-emitting units 310 have similar luminous efficiencies, with the red unit 310 having slightly lower efficiency than the green unit 310. Therefore, when porous graphene is incorporated, the porous graphene LB structure on the blue light-emitting unit 310 results in the greatest increase in light extraction efficiency, compensating for the decrease in luminous efficiency of the blue unit 310. The increase in light extraction efficiency on the red and green light-emitting units 310 is similar to, but less than, that of the blue unit 310. The light extraction efficiency improvement caused by the porous graphene LR structure on unit 310 is slightly higher than that caused by the porous graphene LG structure on green light-emitting unit 310. As a result, the actual luminous efficiency obtained by adding the light extraction efficiency improvement caused by the porous graphene structure on blue light-emitting unit 310, the actual luminous efficiency obtained by adding the light extraction efficiency improvement caused by the porous graphene structure on green light-emitting unit 310, and the actual luminous efficiency obtained by adding the light extraction efficiency improvement caused by the porous graphene structure on red light-emitting unit 310 are the same.

[0040] The actual luminous efficiency is the overall luminous efficiency after the light-emitting unit 310 is combined with the corresponding porous graphene.

[0041] When the overall luminous efficiency of different colored light-emitting units 310 combined with the corresponding porous graphene is consistent, setting the aperture ratio of different colored light-emitting units 310 to be the same can also achieve consistent luminous efficiency of sub-pixels of each color. Therefore, this embodiment solves the problem of different luminous efficiencies of different colored light-emitting units 310 with the same aperture ratio, and can use the same FMM to prepare light-emitting units 310 of different colors, reducing the preparation cost and the difficulty of the preparation process.

[0042] In this embodiment, by setting a light extraction layer 600 composed of porous graphene on the light-emitting layer 300, the light emission rate in the light-emitting layer 300 can be improved. At the same time, the degree of improvement in emission rate varies for porous graphene structures with different pore sizes. Therefore, by specifically setting the pore size of the porous graphene corresponding to different light-emitting units 310, the luminous efficiency of different colored light-emitting units 310 can be unified by combining the improvement in emission rate of porous graphene with the luminous efficiency of the light-emitting unit 310 itself. In this case, setting the light-emitting units 310 of different colors to be of the same size can also achieve consistency in luminous efficiency. Therefore, the same mask can be used for fabrication, avoiding the increase in cost and the increase in fabrication difficulty.

[0043] Furthermore, the porous graphene located on the light-emitting units of different colors has different pore sizes, and the porous graphene with different pore sizes has different light extraction rates for the corresponding light-emitting units.

[0044] By setting a light extraction layer 600 made of porous graphene containing nanoscale pores on the light-emitting layer 300, the light emitted by the light-emitting unit 310 is scattered through the pores in the porous graphene, thereby changing the direction of photon propagation and scattering the light. This greatly avoids the light loss caused by total internal reflection, allowing more light to be released, thereby improving the light extraction rate of the light-emitting unit 310 and improving the overall luminous efficiency.

[0045] The specific pore size within the pore range results in different degrees of improvement in light output efficiency. Therefore, after knowing the unit luminous efficiency of the light-emitting unit 210, it is possible to determine the degree of improvement required to increase the unit luminous efficiency to the target luminous efficiency. Based on this degree of improvement, a specific target pore size is determined within the pore range so that the unit luminous efficiency can be increased to the target luminous efficiency under the target pore size.

[0046] Due to differences in materials and structures, the relationship between unit luminous efficiency, target luminous efficiency, and porosity can change. Therefore, in practical applications, experiments can be conducted based on the given materials and structures to determine the relationship between unit luminous efficiency, target luminous efficiency, and porosity before determining the porosity based on the actual unit luminous efficiency and target luminous efficiency.

[0047] Furthermore, the display panel also includes: An inorganic protective layer 500 is disposed between the light-emitting layer 300 and the light extraction layer 600.

[0048] It is understandable that the light extraction layer 600 needs to be formed with a laser to form porous graphene. The laser will cause high temperature, which may affect the light-emitting layer 300 and its light-emitting performance. Therefore, in this embodiment, after the light-emitting layer 300 is prepared, an inorganic protective layer 500 is first prepared on it, and then the light extraction layer 600 is prepared on the basis of the inorganic protective layer 500, so as to avoid the high temperature during the preparation of the light extraction layer 600 from affecting the light-emitting layer 300.

[0049] The specific materials and preparation process of the inorganic protective layer 500 can be set according to actual needs. For example, the material of the inorganic protective layer 500 can be silicon dioxide (SiO2) or aluminum oxide (Al2O3); the preparation process can be to deposit an inorganic protective layer 500 of 2000~3000 angstroms on the light-emitting layer 300.

[0050] Furthermore, the display panel also includes: A cathode layer 400 is disposed between the light-emitting layer 300 and the inorganic protective layer 500; An isolation column 320 is disposed between adjacent light-emitting units 310; The inorganic protective layer 500 is disconnected at the isolation column 320, and the cathode layer 400 and the light extraction layer 600 are connected at the isolation column 320.

[0051] The light-emitting layer 300 needs to be correspondingly provided with an anode layer 200 and a cathode layer 400 to drive the light emission of the light-emitting unit 310. Generally, an anode layer 200 is provided on the driving backplate 100, a light-emitting layer 300 is provided above the anode layer 200, and a cathode layer 400 is provided above the light-emitting layer 300.

[0052] The cathode layer 400 is used to transmit common signals.

[0053] The isolation pillar 320 is a separation structure between adjacent pixels; the isolation pillar 320 divides the display panel into independent light-emitting areas, and each light-emitting unit 310 is set in an independent light-emitting area.

[0054] The cathode layer 400 adopts a front-covering structure. Therefore, it needs to cross different light-emitting units 310 during fabrication. At the position of the isolation pillar 320, it needs to climb, which will cause the cathode layer 400 to have uneven thickness and stress concentration at the climbing position. This will result in uneven current distribution at different positions on the cathode layer 400, affecting the display effect.

[0055] Since porous graphene has high conductivity, in this embodiment, the inorganic protective layer 500 is disconnected at the isolation pillar 320. The disconnection of the inorganic protective layer 500 enables an electrical connection between the porous graphene L- and the cathode layer 400, thereby forming a point network between the porous graphene L- and the cathode layer 400. This eliminates the non-uniformity of the current in the cathode layer 400 at the isolation pillar 320 and improves the uniformity of the current in the cathode layer 400.

[0056] Meanwhile, since the inorganic protective layer 500 is only disconnected at the isolation pillar 320, the light-emitting unit 310 can still be protected by the inorganic protective layer 500 and avoid the high temperature during the preparation of the light extraction layer 600.

[0057] Further, see Figure 4 The display panel further includes: A first inorganic encapsulation layer 700 is disposed on the light extraction layer 600.

[0058] OLEDs are unstable and extremely sensitive to water, oxygen, and heat. Therefore, the reliability of encapsulation technology is particularly critical in the fabrication of OLED display panels. Flexible and bendable OLED screens are prone to cracking in their encapsulation layer due to repeated bending and deformation. These cracks accelerate the aging of the light-emitting layer 300 devices in the OLED.

[0059] In this embodiment, the light extraction layer 600 is composed of porous graphene. Porous graphene has a three-dimensional porous structure and possesses beneficial flexibility, which can buffer the stress when the flexible OLED is bent and prevent cracks from forming in the encapsulation layer. However, porous graphene has poor water and oxygen barrier properties. Therefore, in this embodiment, a first inorganic encapsulation layer 700 is prepared on the porous graphene. The first inorganic encapsulation layer 700 has a dense structure. During the preparation of the first inorganic encapsulation layer 700, the pores of the uppermost layer of the porous graphene are filled. At the same time, due to its own dense structure, it can effectively isolate water and oxygen from the outside. Through the stacked encapsulation structure composed of porous graphene and the first inorganic encapsulation layer 700, sufficient barrier protection performance can be provided while improving flexibility, thus improving the reliability of the OLED display panel.

[0060] The specific materials and preparation method of the first inorganic encapsulation layer 700 can be set based on actual needs.

[0061] It is understood that the above only describes the necessary structure to achieve the relevant effects, and the specific structure of the OLED display panel can be set according to actual needs; for example, in one feasible embodiment, the OLED display panel specifically includes: Drive backplane 100; An anode layer 200 is disposed on the drive back plate 100; A light-emitting layer 300 is disposed on the anode layer 200, and an isolation pillar 320 is disposed between different light-emitting units 310 in the light-emitting layer 300. The cathode layer 400 is disposed on the light-emitting layer 300 and slopes up at the position of the isolation column 320; An inorganic protective layer 500 is disposed on the cathode layer 400 and is broken at the position of the isolation column 320; The light extraction layer 600 is disposed on the inorganic protective layer 500 and is connected to the cathode layer 400 at the isolation pillar 320 position, and has different structures on the light-emitting units 310 of different colors. The first inorganic encapsulation layer 700 is disposed on the light extraction layer 600 and forms a stacked encapsulation structure with the porous graphene of the light extraction layer 600. An organic encapsulation layer 800 is disposed on top of the first inorganic encapsulation layer 700; The second inorganic encapsulation layer 900 is disposed on top of the organic encapsulation layer 800.

[0062] This invention provides a method for manufacturing a display panel, referring to... Figure 5 , Figure 5 This is a schematic flowchart of the first embodiment of the display panel manufacturing method of the present invention, the method including the following steps: Step S10: Prepare a light-emitting layer, the light-emitting layer comprising light-emitting units corresponding to pixels of different colors, wherein the light-emitting units of different colors are of the same size; The light-emitting layer is a functional layer in an OLED display panel that is composed of organic electroluminescent materials to enable pixel light emission.

[0063] A light-emitting unit is the smallest independent part of the light-emitting layer that emits light; for example, a light-emitting unit can be a red light-emitting unit within a pixel.

[0064] It is understandable that the light-emitting layer specifically contains light-emitting units of three colors: red, green, and blue.

[0065] See Figure 2 , 3 In existing technologies, the red, green, and blue sub-pixels of OLED display panels are set to different sizes. Here, size refers to aperture ratio, that is, the aperture ratio of light-emitting units of different colors is different. For example, in a typical diamond arrangement structure, the aperture ratio of blue sub-pixels can even be twice that of red sub-pixels. Different aperture ratios mean that different photomasks are required for different light-emitting units when evaporating the light-emitting layer.

[0066] In this embodiment, by setting the size of the light-emitting units of different colors to be the same, the light-emitting units of different colors can be fabricated using the same photomask, thereby saving the cost of the photomask and ensuring the consistency of the fabrication effect of the light-emitting units of different colors. On this basis, since the aperture ratio of the light-emitting units is uniform, the light-emitting units of different colors do not have special arrangement. Therefore, the sub-pixels in the OLED can be set as a pixel arrangement structure similar to that of an LCD with horizontal and vertical arrays, further reducing the difficulty of the fabrication process.

[0067] Step S20: Determine the unit luminous efficiency of each of the light-emitting units; After setting the size of the red, green, and blue light-emitting units to be the same, the problem that needs to be addressed is that the three light-emitting units are made of different materials, and different materials have different characteristics. For example, the material used to make the blue light-emitting unit decays faster than that used for the red and green light-emitting units. This will result in different luminous efficiencies among the three colors of light-emitting units. For example, the luminous efficiencies of blue are the lowest, while the luminous efficiencies of green and red are similar but still have some differences. Therefore, after unifying the size of the light-emitting units, it is also necessary to address the differences in luminous efficiencies between the light-emitting units to ensure the accuracy of the display panel.

[0068] Unit luminous efficiency refers to the luminous efficiency of a specific color luminous unit itself.

[0069] Step S30: Determine the target structure of porous graphene corresponding to the unit luminescence efficiency; Step S40: A porous graphene layer is prepared on the light-emitting layer to obtain a light extraction layer. The target structure of the porous graphene located on the light-emitting units of different colors is different. The light extraction rate of the porous graphene with different structures to the corresponding light-emitting units is different. The actual luminous efficiency of each light-emitting unit emitting light through the corresponding porous graphene is the same. The actual luminous efficiency is obtained by superimposing the unit luminous efficiency of the light-emitting unit with the light extraction rate of the corresponding porous graphene.

[0070] In this embodiment, a light extraction layer is provided to eliminate the difference in luminous efficiency between light-emitting units of different colors.

[0071] The light extraction layer is a layer structure disposed on the light-emitting layer to improve the light output efficiency of the light-emitting units in the light-emitting layer.

[0072] In this embodiment, the light extraction layer is specifically constructed using porous graphene.

[0073] Porous graphene is formed by laser irradiation to induce photothermal effects and chemical bond breaking and recombination on the material surface. The specific material can be set according to actual needs, such as porous silica nanoparticles or organic materials with phase separation structure.

[0074] It is understandable that in OLED display panels, the light emitted by the light-emitting unit is affected by multiple total internal reflections between the light-emitting layer and the glass substrate or between the glass substrate and the atmosphere, resulting in light loss and the light not being able to escape from the glass, thus causing a low light output rate.

[0075] By setting a light extraction layer made of porous graphene containing nanoscale pores on top of the light-emitting layer, the light emitted by the light-emitting unit is scattered through the pores in the porous graphene, thereby changing the direction of photon propagation and scattering the light. This greatly avoids the light loss caused by total internal reflection, allowing more light to be released, thereby improving the light extraction rate of the light-emitting unit and improving the overall luminous efficiency.

[0076] It is understandable that the structure of porous graphene is related to the degree to which it improves light extraction efficiency. For example, increasing the porosity of porous graphene can reduce total internal reflection loss more, thereby increasing light extraction efficiency. Furthermore, by setting more layers, the number of light scattering events can be controlled. More layers can achieve more scattering events, thereby further improving light extraction efficiency. However, more scattering also leads to higher scattering loss. Therefore, by combining the setting of various parameters of the porous graphene structure, it is possible to control the light extraction efficiency of the corresponding light-emitting unit.

[0077] Red, green, and blue light-emitting units can all achieve improved light extraction efficiency when set with porous graphene. The specific degree of light extraction efficiency improvement of porous graphene is controllable. Therefore, different porous graphene structures can be set for light-emitting units of different colors, so that the light extraction efficiency improvement of light-emitting units of different colors is different, thereby offsetting the differences in luminous efficiency between light-emitting units of different colors and achieving uniform luminous efficiency.

[0078] As explained above, the blue light-emitting unit has the lowest luminous efficiency, while the red and green light-emitting units have similar luminous efficiencies, with the red unit slightly lower than the green unit. Therefore, when porous graphene is incorporated, the porous graphene structure on the blue light-emitting unit results in the greatest increase in light extraction efficiency, compensating for the decrease in luminous efficiency of the blue unit. The increase in light extraction efficiency on the red and green light-emitting units is similar but less than that on the blue unit, with the latter slightly higher. Consequently, the actual luminous efficiency obtained by combining the luminous efficiency of the blue unit with the increase in light extraction efficiency caused by the porous graphene structure, the green unit with the same increase in light extraction efficiency caused by ...

[0079] The actual luminous efficiency is the overall luminous efficiency after the light-emitting unit is combined with the corresponding porous graphene.

[0080] When the overall luminous efficiency of different color light-emitting units combined with corresponding porous graphene is consistent, setting the aperture ratio of different color light-emitting units to be the same can also achieve consistent luminous efficiency of sub-pixels of different colors. Therefore, this embodiment solves the problem of different luminous efficiencies of light-emitting units of different colors with the same aperture ratio, and can use the same FMM to prepare light-emitting units of different colors, reducing the preparation cost and the difficulty of the preparation process.

[0081] This embodiment improves the light emission rate by setting a light extraction layer composed of porous graphene on the light-emitting layer. Furthermore, the degree to which porous graphene structures with different pore sizes enhance the emission rate varies. Therefore, by specifically setting the pore size of the porous graphene corresponding to different light-emitting units, the combined effect of improved emission rate of porous graphene and the luminous efficiency of the light-emitting units themselves can unify the final luminous efficiency exhibited by light-emitting units of different colors. In this case, setting light-emitting units of different colors to the same size also achieves consistency in luminous efficiency. Therefore, the same mask can be used for fabrication, avoiding increased costs and fabrication difficulty.

[0082] Furthermore, in the second embodiment of the display panel manufacturing method of the present invention based on the first embodiment of the present invention, step S10 includes the following steps: Step S11: Evaporate light-emitting units of different colors using a mask. Step S12: The light-emitting units of different colors use the same mask structure.

[0083] See Figure 2 In the prior art, the aperture ratio of the red light-emitting unit is slightly smaller than that of the green light-emitting unit, and the aperture ratio of the green light-emitting unit is much smaller than that of the blue light-emitting unit. However, in this application, the aperture ratio and shape of the red, green and blue light-emitting units are the same.

[0084] In the prior art, to accommodate the aperture ratio of different colored light-emitting units, separate masks are required for each color light-emitting unit. The aperture on the mask corresponding to the red light-emitting unit is slightly smaller than that of the green one, and the aperture on the mask corresponding to the green light-emitting unit is much smaller than that of the blue one. However, since the light-emitting units in this application are of uniform size, therefore, see [link to previous section]. Figure 3 When setting up the photomask, the photomask used for different colored light-emitting units can be the same, or the same photomask can be used to prepare different colored light-emitting units. Therefore, in the process of preparing the light-emitting layer, only one photomask needs to be set up for different colored light-emitting units. Compared with the existing technology, which requires setting up photomasks with different structures for different colored light-emitting units, it has a lower cost. At the same time, since different colored light-emitting units are prepared based on the same photomask, the preparation process, flow and parameters of different colored light-emitting units can be kept uniform. Therefore, the different colored light-emitting units have better consistency and improve the consistency of the display.

[0085] Furthermore, in the third embodiment of the display panel manufacturing method of the present invention based on the first embodiment of the present invention, step S30 includes the following steps: Step S31: For each color of the light-emitting unit, determine the wavelength range of the corresponding color; Step S32: Match the pore range corresponding to the wavelength range; Step S33: Obtain the target luminous efficiency and the unit luminous efficiency of the light-emitting unit; Step S34: Within the pore range, determine the target pores corresponding to the light extraction rate that can be combined with the unit luminous efficiency to obtain the target luminous efficiency.

[0086] The wavelength range refers to the wavelength range covered by the color of a specific light-emitting unit; for example, the wavelength range corresponding to red is 620-750nm, the wavelength range corresponding to green is 492-577nm, and the wavelength range corresponding to blue is 440-485nm.

[0087] The pore size range refers to the range of pore sizes within porous graphene.

[0088] It is understandable that when the size of the pore is comparable to the wavelength of light, it can effectively scatter that wavelength. However, different colors correspond to different wavelength ranges, so the range of pores that can effectively scatter light also varies for different colors.

[0089] Therefore, in this embodiment, the pore range that can be set in porous graphene is first determined based on the wavelength range of the corresponding light-emitting unit.

[0090] The target luminous efficiency is the final desired total luminous efficiency after each luminescent unit is combined with the corresponding porous graphene.

[0091] The specific pore size within the pore range results in different degrees of improvement in light extraction efficiency. Therefore, after knowing the unit luminous efficiency of the light-emitting unit, it is possible to determine the degree of improvement required to increase the unit luminous efficiency to the target luminous efficiency. Then, based on this degree of improvement, a specific target pore size is determined within the pore range so that the unit luminous efficiency can be increased to the target luminous efficiency under the target pore size.

[0092] Due to differences in materials and structures, the relationship between unit luminous efficiency, target luminous efficiency, and porosity can change. Therefore, in practical applications, experiments can be conducted based on the given materials and structures to determine the relationship between unit luminous efficiency, target luminous efficiency, and porosity before determining the porosity based on the actual unit luminous efficiency and target luminous efficiency.

[0093] In other embodiments, other structural parameters of the porous graphene can be adjusted to achieve the target luminous efficiency, such as the number of layers.

[0094] This embodiment enables accurate determination of the target pore size.

[0095] Furthermore, in the fourth embodiment of the display panel manufacturing method of the present invention based on the first embodiment of the present invention, step S40 includes the following steps: Step S41: An inorganic protective layer is prepared on the light-emitting layer; Step S42: Prepare the porous graphene on the inorganic protective layer to obtain the light extraction layer.

[0096] It is understandable that the light extraction layer needs to be formed into porous graphene by laser. The laser will cause high temperature, which may affect the light-emitting layer and its light-emitting performance. Therefore, in this embodiment, after the light-emitting layer is prepared, an inorganic protective layer is first prepared on it, and then the light extraction layer is prepared on the basis of the inorganic protective layer, so as to avoid the high temperature during the preparation of the light extraction layer from affecting the light-emitting layer.

[0097] The specific materials and preparation process of the inorganic protective layer can be set according to actual needs. For example, the materials of the inorganic protective layer can be silicon dioxide (SiO2) or aluminum oxide (Al2O3); the preparation process can be to deposit an inorganic protective layer of 2000~3000 angstroms on the light-emitting layer.

[0098] Further, step S41 includes the following steps: Step S411: Prepare a cathode layer on the light-emitting layer; Step S412: Prepare the inorganic protective layer on the cathode layer; Step S413: Remove the portion of the inorganic protective layer located at the isolation column position.

[0099] The light-emitting layer needs to be equipped with corresponding anode and cathode layers to drive the light-emitting unit. Generally, an anode layer is set on the driving backplate, a light-emitting layer is set on the anode layer, and a cathode layer is set on the light-emitting layer.

[0100] The cathode layer is used to transmit common signals.

[0101] Isolation pillars are the separation structures between adjacent pixels; isolation pillars divide the display panel into independent light-emitting areas, with each light-emitting unit set in an independent light-emitting area.

[0102] The cathode layer adopts a front-covering structure. Therefore, it needs to span different light-emitting units during fabrication. At the isolation pillar position, it needs to be sloped, which will cause the cathode layer to have uneven thickness and stress concentration at the slope position. This will result in uneven current distribution at different positions on the cathode layer, affecting the display effect.

[0103] Porous graphene has high conductivity. Therefore, in this embodiment, the inorganic protective layer is disconnected at the isolation pillar position. The disconnection of the inorganic protective layer enables the porous graphene to establish an electrical connection with the cathode layer, thereby forming a point network between the porous graphene and the cathode layer. This eliminates the non-uniformity of the current in the cathode layer at the isolation pillar position and improves the uniformity of the current in the cathode layer.

[0104] Meanwhile, since the inorganic protective layer is only disconnected at the isolation column position, the light-emitting unit can still be protected by the inorganic protective layer and avoid the high temperature during the preparation of the light extraction layer.

[0105] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0106] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0107] This invention also protects a display device comprising a display panel, the structure of which is described in the above embodiments and will not be repeated here. Consequently, since the display device of this embodiment adopts the technical solution of the above-described display panel, it possesses all the beneficial effects of the aforementioned display panel.

[0108] In this invention, the terms "first," "second," "third," "fourth," and "fifth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0110] Although embodiments of the present invention have been shown and described above, the scope of protection of the present invention is not limited thereto. It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, and substitutions to the above embodiments within the scope of the present invention, and such changes, modifications, and substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A display panel, characterized by, The display panel comprises: a light-emitting layer comprising light-emitting units corresponding to pixels of different colors, wherein the light-emitting units of different colors are of the same size; a light extraction layer disposed above the light-emitting layer and composed of porous graphene, wherein the porous graphene above the light-emitting units of different colors has different structures, and the porous graphene of different structures has different light extraction rates for the corresponding light-emitting units; each light-emitting unit has the same actual light-emitting efficiency through the corresponding porous graphene, and the actual light-emitting efficiency is obtained by superimposing the unit light-emitting efficiency of the light-emitting unit and the light extraction rate of the corresponding porous graphene.

2. The display panel of claim 1, wherein, The porous graphene above the light-emitting units of different colors has different pores, and the porous graphene of different pores has different light extraction rates for the corresponding light-emitting units.

3. The display panel of claim 1, wherein, The display panel further comprises: an inorganic protective layer disposed between the light-emitting layer and the light extraction layer.

4. The display panel of claim 3, wherein, The display panel further comprises: a cathode layer disposed between the light-emitting layer and the inorganic protective layer; an isolation column disposed between adjacent light-emitting units; the inorganic protective layer is disconnected at the position of the isolation column, and the cathode layer and the light extraction layer are connected at the position of the isolation column.

5. The display panel of claim 1, wherein, The display panel further comprises: a first inorganic encapsulation layer disposed above the light extraction layer.

6. A display panel manufacturing method, comprising: The display panel preparation method comprises: preparing a light-emitting layer comprising light-emitting units corresponding to pixels of different colors, wherein the light-emitting units of different colors are of the same size; determining the unit light-emitting efficiency of each light-emitting unit; determining the target structure of the porous graphene corresponding to the unit light-emitting efficiency; preparing porous graphene above the light-emitting layer to obtain a light extraction layer, wherein the target structure of the porous graphene above the light-emitting units of different colors is different, the porous graphene of different structures has different light extraction rates for the corresponding light-emitting units, each light-emitting unit has the same actual light-emitting efficiency through the corresponding porous graphene, and the actual light-emitting efficiency is obtained by superimposing the unit light-emitting efficiency of the light-emitting unit and the light extraction rate of the corresponding porous graphene.

7. The display panel manufacturing method according to claim 6, wherein The preparation of the light-emitting layer comprises: evaporating different colors of light-emitting units through a mask plate respectively; the mask plates used by the light-emitting units of different colors have consistent structures.

8. The display panel manufacturing method according to claim 6, wherein The determination of the target structure of the porous graphene corresponding to the unit light-emitting efficiency comprises: for each color of the light-emitting unit, determining the wavelength range corresponding to the color; matching the pore range corresponding to the wavelength range; obtaining the target light-emitting efficiency and the unit light-emitting efficiency of the light-emitting unit; within the pore range, determining the target pore corresponding to the light extraction rate that can obtain the target light-emitting efficiency in combination with the unit light-emitting efficiency.

9. The display panel manufacturing method according to claim 6, wherein The preparation of the porous graphene above the light-emitting layer to obtain the light extraction layer comprises: preparing an inorganic protective layer above the light-emitting layer; preparing the porous graphene on the inorganic protective layer to obtain the light extraction layer.

10. The display panel manufacturing method according to claim 9, wherein The preparation of the inorganic protective layer above the light-emitting layer comprises: preparing a cathode layer above the light-emitting layer; forming the inorganic protective layer on the cathode layer; removing a portion of the inorganic protective layer located at the position of the isolation column.

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