Display panel, method for manufacturing display panel, and display device

Abstract

The present application provides a display panel, a method for preparing a display panel, and a display device, wherein the display panel includes: a substrate and a pixel array layer disposed on the substrate, the pixel array layer includes a plurality of pixel units arranged in an array; wherein the pixel units include a first type of pixel unit and a second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, and the target sub-pixel is a sub-pixel whose light-emitting color of the light-emitting layer is green. The display panel adjusts the microcavity effect of the entire light-emitting layer by controlling the thickness arrangement of the green light-emitting layer, thereby achieving different film thicknesses of the green light-emitting layer at different viewing angles, and different degrees of light collection, and the distribution of color points within the surface can achieve a non-shifted state, so that the large viewing angle color deviation meets the level of the normal viewing angle.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular, to a display panel, a method for preparing a display panel, and a display device. Background Art

[0002] The current display technology is gradually transitioning from LCD to OLED, which has the advantages of wide color gamut, fast response time, high contrast, etc. The current mainstream OLED technology adopts top emission, which can achieve high color display under wider viewing angle, eliminate light reflection from glass and ITO, improve light output efficiency, and extend life. In addition, its microcavity effect can narrow the spectrum and improve color purity.

[0003] However, existing OLEDs have problems such as color deviation and brightness attenuation at large viewing angles. This results in very different visual effects when viewing the screen at different angles. In particular, the larger the viewing angle, the greater the color deviation and the lower the brightness. The degree of color deviation of red, green, and blue varies, with red light having the most serious color deviation. Summary of the invention

[0004] The main purpose of the present application is to provide a display panel, a method for manufacturing a display panel and a display device, so as to at least solve the problems of color deviation and brightness attenuation of OLED at a wide viewing angle in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a display panel is provided, comprising: a substrate and a pixel array layer arranged on the substrate, the pixel array layer comprising a plurality of pixel units arranged in an array, one of the pixel units comprising at least three sub-pixels, the sub-pixels comprising a light-emitting layer, and the light-emitting colors of the light-emitting layers of the sub-pixels are different; wherein the pixel units comprise a first type of pixel unit and a second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, the first pixel unit is a pixel unit at the center of the display panel, the second pixel unit is a pixel unit at the edge of the display panel, and the target sub-pixel is a sub-pixel whose light-emitting color of the light-emitting layer is green.

[0006] According to another aspect of the present application, a method for preparing any one of the display panels is provided, the method comprising: providing a substrate; forming the pixel array layer on the substrate, the pixel array layer comprising a plurality of pixel units arranged in an array, one pixel unit comprising at least three sub-pixels, the sub-pixels comprising a light-emitting layer, and the light-emitting colors of the light-emitting layers of the sub-pixels being different; wherein the pixel units comprise a first type of pixel unit and a second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, the first pixel unit is a pixel unit at the center of the display panel, the second pixel unit is a pixel unit at the edge of the display panel, and the target sub-pixel is a sub-pixel whose light-emitting color of the light-emitting layer is green.

[0007] According to another aspect of the present application, a display device is provided, comprising any one of the display panels described above.

[0008] The technical solution of the present application is applied, and the above-mentioned display panel includes: a substrate and a pixel array layer arranged on the substrate, the pixel array layer includes a plurality of pixel units arranged in an array, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, and the target sub-pixel is a sub-image whose light-emitting color of the light-emitting layer is green. The display panel designs the green light-emitting layer into a stepped shape to improve the problem of blue shift of color points under a wide viewing angle. After selecting the cathode, anode materials and peak wavelength, the optimal thickness of the component can be determined. Under the setting of the optimal thickness, the pixel can be arranged in a gradient form from the center point of the display panel to the edge of the panel to adjust the microcavity effect of the entire light-emitting layer, so as to achieve different film thicknesses of the green light-emitting layer under different viewing angles, and different degrees of light collection. The in-plane color point distribution can achieve a non-shifted situation, so that the large viewing angle color deviation meets the level of the normal viewing angle, and solves the problem of viewing angle color deviation and brightness attenuation of OLED under a wide viewing angle in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0010] Figure 1A schematic diagram showing the relationship between the color shift of different pixels and visual angles of a display panel in the prior art is shown;

[0011] Figure 2 A schematic structural diagram of a display panel provided according to an embodiment of the present application is shown;

[0012] Figure 3 A schematic diagram showing the structure of another display panel provided according to an embodiment of the present application is shown;

[0013] Figure 4 A schematic diagram showing a thickness variation of a green light emitting layer of each pixel of a display panel provided according to an embodiment of the present application is shown;

[0014] Figure 5 A schematic diagram showing a thickness variation of a green light emitting layer of each pixel of another display panel provided according to an embodiment of the present application is shown;

[0015] Figure 6 Shows Figure 2 A magnified image of a pixel unit in the display panel;

[0016] Figure 7 Shown along Figure 6 A cross-sectional view of a pixel unit along line AA';

[0017] Figure 8 A schematic cross-sectional structure diagram of another pixel unit provided according to an embodiment of the present application is shown;

[0018] Fig. 9 A schematic diagram showing the structure of another display panel provided according to an embodiment of the present application is shown;

[0019] Fig.10 A schematic diagram showing the structure of another display panel provided according to an embodiment of the present application is shown;

[0020] Fig.11 A schematic diagram of a process of manufacturing a display panel provided according to an embodiment of the present application is shown;

[0021] Fig.12 A schematic structural diagram of a substrate provided according to an embodiment of the present application is shown;

[0022] Fig.13 A schematic diagram showing the structure of another display panel provided according to an embodiment of the present application is shown;

[0023] Fig.14 A schematic diagram showing the structure of another display panel provided according to an embodiment of the present application is shown;

[0024] Fig.15A schematic structural diagram of a display device provided according to an embodiment of the present application is shown.

[0025] The above drawings include the following reference numerals:

[0026] 10, substrate; 11, pixel unit; 11a, first pixel unit; 11b, second pixel unit; 111, first sub-pixel; 111a, first anode; 111b, first cathode; 111c, first light-emitting layer; HIL1, first hole injection layer; HTL1, first hole transport layer; EBL1, first electron blocking layer; HBL1, first hole blocking layer; ETL1, first electron transport layer; EIL1, first electron injection layer; 112, second sub-pixel; 112a, second anode; 112b, second cathode; 112c, second light-emitting layer; HIL2, second hole injection layer; HTL2, second hole transport layer; EBL2, second electron blocking layer; HBL2, second hole blocking layer; ETL2, second electron transport layer; EIL2, second electron injection layer; 113, third sub-pixel; 113a, third anode; 113b, third cathode; 113c, third light-emitting layer; HIL3, third hole injection layer; HTL 3, third hole transport layer; EBL3, third electron blocking layer; HBL3, third hole blocking layer; ETL3, third electron transport layer; EIL3, third electron injection layer; 114, fourth sub-pixel; 114a, fourth anode; 114b, fourth cathode; 114c, fourth light-emitting layer; HIL4, fourth hole injection layer; HTL4, fourth hole transport layer; EBL4, fourth electron blocking layer; HBL4, fourth hole blocking layer; ETL4, fourth electron transport layer; transport layer; EIL4, fourth electron injection layer; 20, pixel array layer; 30, first electrode layer; 40, hole transport layer; 50, electron transport layer; 60, common electrode; 70, encapsulation layer; 80, pixel defining layer; 90, insulating layer; 100, covering layer; 400, display panel; TR1, first transistor; TR2, second transistor; TR3, third transistor; LAL1, first light absorption layer; LAL2, second light absorption layer; LAL3, third light absorption layer. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0031] Active-matrix organic light-emitting diode: active-matrix organic light-emitting diode, referred to as AMOLED.

[0032] As introduced in the background technology, in the prior art, AMOLED has color deviation and brightness attenuation problems at a wide viewing angle, resulting in significant differences in visual effects when viewing the screen at different angles. Figure 1 As shown, the larger the viewing angle, the greater the color shift and the lower the brightness. The degree of color shift of red, green, and blue varies, and the red light color shift is the most serious. Among them, JNCD is the abbreviation of "Just Noticeable Color Difference", which means "only noticeable color difference". In display technology, JNCD is often used to describe the performance of a display in terms of color accuracy. A low JNCD value means that the display can accurately present colors, making it impossible for users to perceive subtle differences between different colors. Generally speaking, the lower the JNCD value, the higher the color accuracy of the display.

[0033] Since AMOLED is self-luminous, its light-emitting layer, transmission semiconductor, transparent electrode, inorganic insulation layer, etc. have thin film layers with different refractive indices, and their thickness is usually within the order of magnitude of the emission wavelength. The light output efficiency will be reduced due to the optical path difference at different viewing angles. At a wide viewing angle, RGB will experience different degrees of brightness attenuation and spectrum blue shift, which will cause the white light to be color cast.

[0034] In order to solve the problems of color shift and brightness attenuation of OLED at a wide viewing angle in the prior art, the embodiments of the present application provide a display panel, a method for preparing a display panel, and a display device.

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0036] Figure 2 is a schematic diagram of the structure of a display panel according to an embodiment of the present application. Figure 2 As shown, the display panel includes: a substrate 10 and a pixel array layer arranged on the substrate, the pixel array layer includes a plurality of pixel units 11 arranged in an array, one of the pixel units 11 includes at least three sub-pixels, the sub-pixels include a light-emitting layer, and the light-emitting colors of the light-emitting layers of the sub-pixels are different; wherein the pixel units 11 include a first type of pixel unit and a second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit 11a is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit 11b, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, the first pixel unit 11a is a pixel unit at the center of the display panel, the second pixel unit 11b is a pixel unit at the edge of the display panel, and the target sub-pixel is a sub-pixel whose light-emitting color of the light-emitting layer is green.

[0037] The above-mentioned display panel of the present application includes: a substrate and a pixel array layer arranged on the substrate, the pixel array layer includes a plurality of pixel units arranged in an array, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, and the target sub-pixel is a sub-image whose light-emitting color of the light-emitting layer is green. The display panel designs the green light-emitting layer into a stepped shape to improve the problem of blue shift of color points under a wide viewing angle. The pixels of the display panel are arranged in a gradient form from the center point of the display panel to the edge of the panel to adjust the microcavity effect of the entire light-emitting layer, so as to achieve different film thicknesses of the green light-emitting layer under different viewing angles, and different degrees of light collection, and the in-plane color point distribution can achieve a non-shifted situation, so that the large viewing angle color deviation meets the level of the normal viewing angle, solving the problem of viewing angle color deviation and brightness attenuation of OLED under a wide viewing angle in the prior art.

[0038] Among them, according to the prior art, the current RGB light-emitting layer has different attenuation degrees due to the life of the material. Under a wide viewing angle, the color point is blue-shifted, and the visual is reddish under a wide viewing angle. The color deviation under a wide viewing angle is larger than 30°. That is, the larger the viewing angle, the more serious the deviation of the color point. Therefore, by adjusting the thickness of the light-emitting layer of each pixel unit, the microcavity effect of the entire light-emitting layer is adjusted, thereby improving the problem of blue-shift of the color point under a wide viewing angle.

[0039] Since the larger the viewing angle, the more serious the deviation of the color point, the pixel units of the display panel can arrange the thickness of the green light-emitting layer in a gradient from the center point to the edge of the display panel, that is, the thickness of the green light-emitting layer of the pixel unit located at the center of the display panel is larger, and the thickness of the green light-emitting layer of the pixel unit located at the edge of the display panel is smaller.

[0040] In some embodiments, the thickness of the green light-emitting layer of the pixel unit closer to the center of the display panel between two adjacent pixel units is greater than or equal to the thickness of the green light-emitting layer of the pixel unit farther from the center of the display panel. That is, the thickness of the green light-emitting layer of the pixel units arranged from the center to the edge of the display panel can be calculated according to In descending order, you can also follow set up.

[0041] In some examples, the thickness of the light emitting layer of the target sub-pixel of the pixel unit decreases along a preset direction according to a preset gradient value.

[0042] Among them, in the existing display panel, the color shift problem is easy to occur under a large viewing angle, that is, when the viewing angle of the display panel is 45°, the color shift cannot reach the required specification of 5JNCD or less, that is, the color shift is greater than 5JNCD, and the color shift is serious. Since the viewing angle at the center of the display panel is smaller and the viewing angle at the edge of the display panel is larger, the thickness of the green light-emitting layer of the pixel unit in the center of the display panel needs to be set thicker, while the thickness of the green light-emitting layer of the pixel unit at the edge of the display panel needs to be set thinner. The color shift phenomenon can be effectively changed by decreasing the thickness of the light-emitting layer of the target sub-pixel of the pixel unit along the preset direction according to the preset gradient value.

[0043] In some embodiments, the preset direction is a direction from the center of the display panel to any edge of the display panel.

[0044] The schematic diagram of the preset direction is as follows: Figure 3 As shown, the thickness of the light emitting layer of the target sub-pixel of the pixel unit on the display panel is arranged as follows Figure 4 and Figure 5 As shown, the AA area is the display area, the center of the AA area is the center of the display area on the display panel, and the preset direction can be the X-axis direction or the Y-axis direction. Since the display panel is rectangular, when the thickness of the light-emitting layer of the target sub-pixel of the pixel unit in both the X-axis direction and the Y-axis direction decreases according to the preset gradient value, the thickness of the light-emitting layer of the target sub-pixel of the pixel unit in the center part of the display panel can be decreased along the thickness of the light-emitting layer of the target sub-pixel of the pixel unit in the edge part of the display panel.

[0045] In some examples, the preset gradient value is

[0046] The value of the preset gradient value is obtained through experiments. When the preset gradient value is used to set the thickness of the target sub-pixel of the pixel unit on the display panel, the color purity and efficiency can be better improved, so that the greater the microcavity effect, the narrower the half-width of the light wave, and the luminous intensity and color will change with the viewing angle, thereby adjusting the microcavity effect of the entire light-emitting layer, so that the green light-emitting layer has different film thicknesses and different light collection degrees at different viewing angles, and the color point distribution in the plane can achieve no offset, so that the large viewing angle color deviation meets the level of the normal viewing angle.

[0047] In some embodiments, the thickness of the light emitting layer of the target sub-pixel of the first pixel unit is

[0048] Since different materials have different luminous efficiencies and color point ranges, and different colored luminous layers correspond to different wavelengths, the red wavelength is longer and the blue wavelength is shorter. Therefore, in order to achieve different color luminous effects in a pixel, it is necessary to control the thickness of each luminous layer to achieve the best luminous effect. Since the red wavelength is longer, less material is required to achieve the ideal luminous effect, so the thickness of the red luminous layer is lower; while the blue wavelength is shorter, more material is required to achieve the ideal luminous effect, so the thickness of the blue luminous layer is higher.

[0049] That is, in general, the thickness range of the light-emitting layer of a sub-pixel with a red light-emitting color is The thickness range of the light-emitting layer of the sub-pixel with green light emission color is The thickness range of the light-emitting layer of the sub-pixel with blue light emission color is However, in order to solve the color deviation problem of the display panel, the thickness of the light-emitting layer of the target sub-pixel of the pixel unit at the center of the display panel will be thicker. After experiments, it is found that the thickness of the light-emitting layer of the target sub-pixel of the pixel unit at the center of the display panel is In this case, the distribution of color points within the plane can be achieved without offset, and the large viewing angle can meet the level of positive viewing angle.

[0050] On this basis, even if the thickness of the light-emitting layer of the target sub-pixel of the pixel unit decreases from the center of the display panel to the edge of the display panel, the thickness of the light-emitting layer of the target sub-pixel of the pixel unit at the edge of the display panel is greater than the thickness of the light-emitting layer of the sub-pixel whose light-emitting color is red, that is, the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit is greater than

[0051] Figure 6 yes Figure 2 An enlarged view of a pixel unit in Figure 6 As shown, the pixel unit includes a first sub-pixel 111, a second sub-pixel 112, a third sub-pixel 113 and a fourth sub-pixel 114, and the light-emitting colors of any two sub-pixels are the same.

[0052] Among them, the pixel unit of the panel is the smallest controllable point on the display screen, and they can form an image through different colors. In the display panel, each pixel unit is composed of one or more sub-pixels. Generally, it is composed of three sub-pixels of R, G, and B, among which the three sub-pixels of RGB represent red, green, and blue, and various colors can be presented through different combinations of these three colors. In this example, the pixel unit is composed of four sub-pixels: the first sub-pixel, the second sub-pixel, the third sub-pixel, and the fourth sub-pixel. Among them, the first sub-pixel is red, the second sub-pixel is green, the third sub-pixel is blue, and the fourth sub-pixel is green. The two green sub-pixels can provide more brightness and color details, thereby improving the display effect and color accuracy. Therefore, compared with the three sub-pixels of RGB, the four sub-pixels of RGBG can provide more delicate and realistic color performance in image display.

[0053] Among them, in the pixel unit is Figure 1 In the case of the pixel unit 11c shown in , that is, one green sub-pixel in the pixel unit is closer to the center of the display panel and the other green sub-pixel is farther from the center of the display panel, the thickness of the green sub-pixel closer to the center of the display panel is greater than the green sub-pixel farther from the center of the display panel.

[0054] In some instances, the emission wavelength of the first sub-pixel is greater than the emission wavelength of the second sub-pixel, the emission wavelength of the second sub-pixel is greater than the emission wavelength of the third sub-pixel, and the emission wavelength of the second sub-pixel is the same as the emission wavelength of the fourth sub-pixel.

[0055] Among them, the luminous color of the first sub-pixel is red, the luminous color of the second sub-pixel is green, the luminous color of the third sub-pixel is blue, and the luminous color of the fourth sub-pixel is green. The first sub-pixel emits red light with a wavelength of 622nm to 770nm, the second sub-pixel emits green light with a wavelength of 525nm to 570nm, and the third sub-pixel emits blue light with a wavelength of 450nm to 475nm. Compared with the three sub-pixels of RGB, the four sub-pixels of RGBG can provide more delicate and realistic color performance in image display.

[0056] In some instances, such as Figure 7As shown, the first sub-pixel 111 includes a first anode 111a, a first cathode 111b, and a first light-emitting layer 111c located between the first anode 111a and the first cathode 111b; the second sub-pixel 112 includes a second anode 112a, a second cathode 112b, and a second light-emitting layer 112c located between the second anode 112a and the second cathode 112b; the third sub-pixel 113 includes a third anode 113a, a third cathode 113b, and a third light-emitting layer 113c located between the third anode 113a and the second cathode 113b. a third light-emitting layer 113c between the third cathodes 113b; the fourth sub-pixel 114 includes a fourth anode 114a, a fourth cathode 114b and a fourth light-emitting layer 114c between the fourth anode 114a and the fourth cathode 114b; wherein, when the distance between the fourth sub-pixel 114 and the center of the display panel is less than the distance between the second sub-pixel 112 and the center of the display panel, the thickness of the fourth light-emitting layer 114c is greater than or equal to the thickness of the second light-emitting layer 112c.

[0057] The materials of the first light-emitting layer 111c, the second light-emitting layer 112c, the third light-emitting layer 113c and the fourth light-emitting layer 114c may be organic light-emitting materials (OLED). In this embodiment, the material of the first light-emitting layer 111c may be an OLED that emits red light, the materials of the second light-emitting layer 112c and the fourth light-emitting layer 114c may be an OLED that emits green light, and the material of the third light-emitting layer 113c may be an OLED that emits blue light. In other words, the first sub-pixel structure 111 emits red light, the second sub-pixel structure 112 and the fourth sub-pixel structure 114 emit green light, and the third sub-pixel structure 113 emits blue light. The first sub-pixel structure 111, the second sub-pixel structure 112, the third sub-pixel structure 113 and the fourth sub-pixel structure 114 of the three primary colors of red, green and blue are alternately distributed.

[0058] The material of the first anode 111a, the second anode 112a, the third anode 113a, and the fourth anode 114a may be a reflective material. The reflective material may include silver (Ag) and its alloys, aluminum (Al) and its alloys, such as silver (Ag), an alloy of silver and lead (Ag:Pb), an alloy of aluminum and neodymium (Al:Nd), an alloy of silver, platinum, and copper (Ag:Pt:Cu), etc. When silver and its alloys are used as the reflective material, a layer of ITO, IZO, or IGZO may be disposed between the first anode 111a, the second anode 112a, the third anode 113a, and the fourth anode 114a and the organic light-emitting material layer, respectively.

[0059] The material of the first cathode 111b, the second cathode 112b, the third cathode 113b and the fourth cathode 114b may be a material having a partially light-transmitting and partially light-reflecting function (semi-transmitting and semi-reflecting material). The first cathode 111b, the second cathode 112b, the third cathode 113b and the fourth cathode 114b may be a single-layer structure, and the material of the single-layer structure may include: at least one of magnesium, silver, and aluminum, for example: a mixture of magnesium and silver or a mixture of aluminum and silver. The first cathode 111b, the second cathode 112b, the third cathode 113b and the fourth cathode 114b may also be a three-layer structure of a transparent conductive layer, an intermediate layer, and a transparent conductive layer. The material of the transparent conductive layer may be at least one of ITO, IZO and IGZO, and the material of the intermediate layer may include: at least one of magnesium, silver, and aluminum, for example: a mixture of magnesium and silver or a mixture of aluminum and silver. In other words, the display panel is a top-emitting structure.

[0060] In this embodiment, the first anode 111a, the second anode 112a, the third anode 113a and the fourth anode 114a are close to the substrate 10, and the first cathode 111b, the second cathode 112b, the third cathode 113b and the fourth cathode 114b are far away from the substrate 10.

[0061] In some instances, such as Figure 8 As shown, the first sub-pixel 111 includes a first anode 111a, a first hole injection layer HIL1, a first hole transport layer HTL1, a first electron blocking layer EBL1, a first light emitting layer 111c, a first hole blocking layer HBL1, a first electron transport layer ETL1, a first electron injection layer EIL1 and a first cathode 111b in sequence;

[0062] The second sub-pixel 112 includes a second anode 112a, a second hole injection layer HIL2, a second hole transport layer HTL2, a second electron blocking layer EBL2, a second light emitting layer 112c, a second hole blocking layer HBL2, a second electron transport layer ETL2, a second electron injection layer EIL2 and a second cathode 112b in sequence;

[0063] The third sub-pixel 113 includes a third anode 113a, a third hole injection layer HIL3, a third hole transport layer HTL3, a third electron blocking layer EBL3, a third light emitting layer 113c, a third hole blocking layer HBL3, a third electron transport layer ETL3, a third electron injection layer EIL3 and a third cathode 113b in sequence;

[0064] The fourth sub-pixel 114 includes a fourth anode 114a, a fourth hole injection layer HIL4, a fourth hole transport layer HTL4, a fourth electron blocking layer EBL4, a fourth light-emitting layer 114c, a fourth hole blocking layer HBL4, a fourth electron transport layer ETL4, a fourth electron injection layer EIL4 and a fourth cathode 114b in sequence.

[0065] The thickness range of the first anode, the second anode, the third anode and the fourth anode is The thickness range of the first hole injection layer, the second hole injection layer, the third hole injection layer and the fourth hole injection layer is within The first hole injection layer, the second hole injection layer, the third hole injection layer and the fourth hole injection layer are n-type organic material copper phthalocyanine (CuPc), and the thickness range of the first hole transport layer, the second hole transport layer, the third hole transport layer and the fourth hole transport layer is The first hole transport layer, the second hole transport layer, the third hole transport layer and the fourth hole transport layer are n-type organic materials Spin-2NPB, wherein Spin-2NPB is a triphenylfluorenylaniline compound, and the thickness of the first electron transport layer, the second electron transport layer, the third electron transport layer and the fourth electron transport layer is The first electron transport layer, the second electron transport layer, the third electron transport layer and the fourth electron transport layer are n-type organic material Alq3 (8-hydroxyquinoline and aluminum), and the thickness range of the first electron injection layer, the second electron injection layer, the third electron injection layer and the fourth electron injection layer is The materials of the first electron injection layer, the second electron injection layer, the third electron injection layer and the fourth electron injection layer are LiF or Li2O, and the thickness range of the first cathode, the second cathode, the third cathode and the fourth cathode is The material of the first cathode, the second cathode, the third cathode and the fourth cathode is Mg or Ag.

[0066] Among them, after selecting the cathode, anode materials and peak wavelength, the optimal thickness of the component can be determined. The luminescence spectrum is divided into photoluminescence (PL) spectrum and electroluminescence (EL) spectrum. Among them, the electroluminescence spectrum is the spectrum of the device under different driving voltages and currents using electrical energy excitation (cathode anode voltage). The absorption spectrum and luminescence spectrum of organic materials are generally broadband spectra, and the half-height width of the spectrum peak is approximately between 100-200nm. This is the result of the superposition of the vibration energy level and the electronic energy level of the organic molecule. Compared with inorganic materials, the color purity is much worse. In the same organic layer, the molecular functional groups in the excited singlet state and the ground state react chemically to form an excited dimer; the molecular functional groups of the two adjacent organic functional layers react chemically to form an exciplex. The excited dimer and the exciplex will capture the excitons of the original luminescence center, causing the luminescence spectrum to change. Select the voltage setting that can excite the luminescence spectrum with the maximum efficiency as the voltage value of the cathode and anode. After selecting the cathode, anode materials and peak wavelength, the optimal thickness of the component can be determined. Under the setting of the optimal thickness, the film thickness is fine-tuned for a wide viewing angle to improve color purity and efficiency. As a result, the greater the microcavity effect, the narrower the half-width of the light wave, and the luminous intensity and color will change with the viewing angle.

[0067] In some instances, such as Fig. 9 As shown, the display panel includes a substrate 10, a first electrode layer 30, a hole transport layer 40, a light emitting layer, an electron transport layer 50 and a common electrode 60 arranged in sequence. The first electrode layer 30 is an anode, the hole transport layer 40 is completely filled between the light emitting layer and the first electrode layer 30, and the light emitting layer includes a first light emitting layer 111c, a second light emitting layer 112c, a third light emitting layer 113c and a fourth light emitting layer 114c. Fig. 9 As shown, from the first edge of the display panel to the second edge along the X-axis direction, the thickness of the green light-emitting layer first increases and then decreases, corresponding to the thickness of the green light-emitting layer gradually increasing from the first edge of the display panel to the center of the display panel, and gradually decreasing from the center of the display panel to the second edge.

[0068] In some examples, an electron transport layer may also be used to fill the portion between the light-emitting layer and the first electrode layer, which will not be elaborated in detail herein.

[0069] In some instances, such as Fig.10 As shown, the display panel further includes: an encapsulation layer 70 , and the encapsulation layer 70 is located on a side of the pixel array layer 20 away from the substrate 10 .

[0070] The encapsulation layer generally comprises a three-layer structure of an inorganic layer-an organic layer-an inorganic layer, and the encapsulation layer can prevent impurities, moisture, etc. from penetrating the pixel array layer from the outside. The encapsulation layer may include at least one of an inorganic encapsulation layer and an organic encapsulation layer.

[0071] For example, the inorganic encapsulation layer may include at least one of silicon oxide, silicon nitride, silicon oxynitride, and the like, and the organic encapsulation layer may include at least one of polymer curing materials such as polyacrylate, and the like.

[0072] Fig.11 is a logical schematic diagram of a method for preparing a display panel, such as Fig.11 As shown, the above method includes:

[0073] Step S101, as Fig.12 As shown, a substrate 10 is provided;

[0074] Step S102, as Fig.13 As shown, the pixel array layer 20 is formed on the substrate 10, and the pixel array layer 20 includes a plurality of pixel units arranged in an array, and one pixel unit includes at least three sub-pixels, and the sub-pixels include a light-emitting layer, and the light-emitting colors of the light-emitting layers of the sub-pixels are different;

[0075] Among them, the above-mentioned pixel units include a first type of pixel units and a second type of pixel units, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel units is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel units, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit, the distance between the above-mentioned first type of pixel unit and the center of the display panel is less than the distance between the above-mentioned second type of pixel unit and the center of the above-mentioned display panel, the above-mentioned first pixel unit is a pixel unit at the center of the above-mentioned display panel, the above-mentioned second pixel unit is a pixel unit at the edge of the above-mentioned display panel, and the above-mentioned target sub-pixel is the above-mentioned sub-pixel whose light-emitting color of the light-emitting layer is green.

[0076] The display panel produced by the above-mentioned preparation method of the present application designs the green light-emitting layer into a stepped shape to improve the problem of blue shift of color points under wide viewing angles. The pixels of the display panel start from the center point of the display panel, and the thickness of the green light-emitting layer is arranged in a gradient form toward the edge of the panel, thereby adjusting the microcavity effect of the entire light-emitting layer, so as to achieve different film thicknesses of the green light-emitting layer under different viewing angles, and different degrees of light collection. The distribution of color points within the surface can achieve a non-offset situation, so that the large viewing angle color deviation meets the level of the normal viewing angle, solving the problem of viewing angle color deviation and brightness attenuation of OLED under wide viewing angles in the prior art.

[0077] In some instances, such as Fig.14As shown, forming the above-mentioned pixel array layer on the above-mentioned substrate includes: forming a first electrode layer on one side of the above-mentioned substrate 10; forming a preliminary pixel defining layer on the side of the above-mentioned first electrode layer away from the substrate; patterning the above-mentioned preliminary pixel defining layer to obtain a plurality of first openings, and the remaining above-mentioned preliminary pixel defining layer forms the above-mentioned pixel defining layer 80; forming a light-emitting layer in the above-mentioned first openings; forming a common electrode 60 on the side of the above-mentioned light-emitting layer away from the above-mentioned substrate to obtain the above-mentioned pixel array layer.

[0078] In some instances, such as Fig.10 As shown, the method further includes: forming an encapsulation layer 70 on a side of the pixel array layer 20 away from the substrate 10 .

[0079] like Fig.14 As shown, a first transistor TR1, a second transistor TR2, a third transistor TR3 and an insulating layer 90 are also formed on the substrate 10, and a first electrode layer, a pixel defining layer 80, a light-emitting layer, a common electrode 60, a covering layer 100, a first light absorption layer LAL1, a second light absorption layer LAL2, a third light absorption layer LAL3 and an encapsulation layer 70 are sequentially formed on the insulating layer 90.

[0080] Among them, the first electrode layer includes a first anode 111a, a second anode 112a, and a third anode 113a, and a pixel defining layer 80 may be arranged on the insulating layer 90 and the first anode 111a, the second anode 112a, and the third anode 113a. The pixel defining layer 80 may overlap with the non-luminous area. The pixel defining layer 80 may cover the side (e.g., two sides) of each of the first anode 111a, the second anode 112a, and the third anode 113a, and may expose at least a portion of the upper surface of each of the first anode 111a, the second anode 112a, and the third anode 113a. The pixel defining layer may include an organic material and / or an inorganic material. In an embodiment, the pixel defining layer may include an organic material. For example, the pixel defining layer may include at least one of a photoresist, a polyacrylic resin, a polyimide resin, a polyamide resin, a siloxane resin, an acrylic resin, an epoxy resin, etc. These may be used alone or in combination with each other.

[0081] The pixel array layer is also provided with a driving circuit layer, and the driving circuit layer is provided with a plurality of pixel driving circuits (such as Fig.14 In the embodiment of FIG. 1 , the pixel driving circuit is electrically connected to the first electrode layer in the pixel array layer, and the pixel driving circuit is used to provide a driving signal for the sub-pixel to ensure normal display. The specific configuration of the pixel driving circuit may be different depending on the driving mode of the sub-pixel.

[0082] Specifically, when the material of the first light-emitting layer 111c is an OLED that emits red light, the material of the second light-emitting layer 112c is an OLED that emits green light, and the material of the third light-emitting layer 113c is an OLED that emits blue light, and the driving mode of the sub-pixel is active driving, the pixel driving circuit includes a plurality of transistors (such as Fig.14 The first transistor TR1, the second transistor TR2, and the third transistor TR3 are shown in FIG. 1 ), and the first light-emitting layer 111c, the second light-emitting layer 112c, and the third light-emitting layer 113c are driven to emit light by the first transistor TR1, the second transistor TR2, and the third transistor TR3, respectively. Similarly, the pixel driving circuit may also be a 2T1C circuit, i.e., a circuit having 2 transistors and 1 storage capacitor, or a 7T1C circuit, i.e., a circuit having 7 transistors and 1 storage capacitor, etc. The embodiment of the present invention does not limit the specific structure of the pixel driving circuit.

[0083] In some instances, such as Fig.14 As shown, a cover layer 100 may be formed on the common electrode 60, and a first light absorbing layer LAL1, a second light absorbing layer LAL2, and a third light absorbing layer LAL3 may be formed on the cover layer 100. The first light absorbing layer LAL1 may be formed in the first light emitting region, the second light absorbing layer LAL2 may be formed in the second light emitting region, and the third light absorbing layer LAL3 may be formed in the third light emitting region. For example, each of the first light absorbing layer LAL1, the second light absorbing layer LAL2, and the third light absorbing layer LAL3 may be formed by using at least one of a metal, a silicon compound, a metal oxide, and the like.

[0084] Fig.15 is a schematic diagram of the structure of a display device, such as Fig.15 As shown, it includes any one of the display panels 400. The display device can be: electronic paper, mobile phone, tablet computer, television, notebook computer, digital photo frame, navigator and any other product or component with display function.

[0085] The above-mentioned display device of the present application designs the green light-emitting layer in the middle of the display panel into a stepped shape to improve the problem of blue shift of color points under wide viewing angles. The pixels of the display panel are arranged in a gradient form from the center point of the display panel to the edge of the panel to adjust the microcavity effect of the entire light-emitting layer, so that the film thickness of the green light-emitting layer is different under different viewing angles, and the degree of light collection is also different, and the color point distribution in the surface can be achieved without offset.

[0086] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0087] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0088] 1) The above-mentioned display panel of the present application comprises: a substrate and a pixel array layer arranged on the substrate, the pixel array layer comprises a plurality of pixel units arranged in an array, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, and the target sub-pixel is a sub-image whose light-emitting color of the light-emitting layer is green. The display panel designs the green light-emitting layer into a stepped shape to improve the problem of blue shift of color points under a wide viewing angle. The pixels of the display panel are arranged in a gradient form from the center point of the display panel to the edge of the panel to adjust the microcavity effect of the entire light-emitting layer, so as to achieve different film thicknesses of the green light-emitting layer under different viewing angles, and different degrees of light collection, and the in-plane color point distribution can achieve a non-offset situation, so that the large viewing angle color deviation meets the level of the normal viewing angle, and solves the problem of viewing angle color deviation and brightness attenuation of OLED under a wide viewing angle in the prior art.

[0089] 2) The display panel produced by the above-mentioned preparation method of the present application designs the green light-emitting layer into a stepped shape to improve the problem of blue shift of color points under wide viewing angles. The pixels of the display panel start from the center point of the display panel, and the thickness of the green light-emitting layer is arranged in a gradient form toward the edge of the panel, thereby adjusting the microcavity effect of the entire light-emitting layer, so that the film thickness of the green light-emitting layer is different under different viewing angles, and the degree of light collection is also different. The distribution of color points in the plane can achieve no offset, so that the large viewing angle color deviation meets the level of the normal viewing angle, solving the problem of viewing angle color deviation and brightness attenuation of OLED under wide viewing angles in the prior art.

[0090] 3) The above-mentioned display device of the present application designs the green light-emitting layer in the middle of the display panel into a stepped shape to improve the problem of blue shift of color points under wide viewing angles. The pixels of the display panel are arranged in a gradient form from the center point of the display panel to the edge of the panel to adjust the microcavity effect of the entire light-emitting layer, so that the film thickness of the green light-emitting layer is different under different viewing angles, and the degree of light collection is also different, and the color point distribution in the surface can be achieved without offset.

[0091] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A display panel, characterized in that: include: A substrate and a pixel array layer disposed on the substrate, the pixel array layer comprising a plurality of pixel units arranged in an array, one of the pixel units comprising at least three sub-pixels, the sub-pixels comprising a light-emitting layer, and the light-emitting colors of the light-emitting layers of the sub-pixels being different; Among them, the pixel unit includes a first type of pixel unit and a second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, the first pixel unit is a pixel unit at the center of the display panel, the second pixel unit is a pixel unit at the edge of the display panel, and the target sub-pixel is the sub-pixel whose light-emitting color of the light-emitting layer is green.

2. The display panel according to claim 1, characterized in that: The thickness of the light emitting layer of the target sub-pixel of the pixel unit decreases along a preset direction according to a preset gradient value.

3. The display panel according to claim 2, characterized in that: The preset direction is a direction from the center of the display panel to any edge of the display panel.

4. The display panel according to claim 2, characterized in that: The preset gradient value is 5. The display panel according to claim 1, characterized in that: The thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is 6. The display panel according to claim 1, characterized in that: The pixel unit includes a first sub-pixel, a second sub-pixel, a third sub-pixel and a fourth sub-pixel, and the luminous colors of any two sub-pixels are the same.

7. The display panel according to claim 6, characterized in that: The emission wavelength of the first sub-pixel is greater than that of the second sub-pixel, the emission wavelength of the second sub-pixel is greater than that of the third sub-pixel, and the emission wavelength of the second sub-pixel is the same as that of the fourth sub-pixel.

8. The display panel according to claim 7, characterized in that: The first sub-pixel includes a first anode, a first cathode, and a first light-emitting layer located between the first anode and the first cathode; The second sub-pixel includes a second anode, a second cathode, and a second light emitting layer located between the second anode and the second cathode; The third sub-pixel comprises a third anode, a third cathode and a third light emitting layer located between the third anode and the third cathode; The fourth sub-pixel includes a fourth anode, a fourth cathode, and a fourth light-emitting layer located between the fourth anode and the fourth cathode; Wherein, when the distance between the fourth sub-pixel and the center of the display panel is smaller than the distance between the second sub-pixel and the center of the display panel, the thickness of the fourth light-emitting layer is greater than or equal to the thickness of the second light-emitting layer.

9. The display panel according to claim 6, characterized in that: The first sub-pixel includes, in sequence, a first anode, a first hole injection layer, a first hole transport layer, a first electron blocking layer, a first light emitting layer, a first hole blocking layer, a first electron transport layer, a first electron injection layer and a first cathode; The second sub-pixel includes, in sequence, a second anode, a second hole injection layer, a second hole transport layer, a second electron blocking layer, a second light emitting layer, a second hole blocking layer, a second electron transport layer, a second electron injection layer and a second cathode; The third sub-pixel includes, in sequence, a third anode, a third hole injection layer, a third hole transport layer, a third electron blocking layer, a third light emitting layer, a third hole blocking layer, a third electron transport layer, a third electron injection layer and a third cathode; The fourth subpixel includes a fourth anode, a fourth hole injection layer, a fourth hole transport layer, a fourth electron blocking layer, a fourth light emitting layer, a fourth hole blocking layer, a fourth electron transport layer, a fourth electron injection layer and a fourth cathode in sequence.

10. The display panel according to claim 1, characterized in that: The display panel further includes: The encapsulation layer is located on a side of the pixel array layer away from the substrate.

11. A method for preparing a display panel according to any one of claims 1 to 10, characterized in that: The method comprises: providing a substrate; The pixel array layer is formed on the substrate, wherein the pixel array layer includes a plurality of pixel units arranged in an array, wherein one pixel unit includes at least three sub-pixels, and the sub-pixels include a light-emitting layer, and the light-emitting colors of the light-emitting layers of the sub-pixels are different; Among them, the pixel unit includes a first type of pixel unit and a second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first type of pixel unit is greater than or equal to the thickness of the light-emitting layer of the target sub-pixel of the second type of pixel unit, the thickness of the light-emitting layer of the target sub-pixel of the first pixel unit is greater than the thickness of the light-emitting layer of the target sub-pixel of the second pixel unit, the distance between the first type of pixel unit and the center of the display panel is less than the distance between the second type of pixel unit and the center of the display panel, the first pixel unit is a pixel unit at the center of the display panel, the second pixel unit is a pixel unit at the edge of the display panel, and the target sub-pixel is the sub-pixel whose light-emitting color of the light-emitting layer is green.

12. The method for preparing a display panel according to claim 10, characterized in that: Forming the pixel array layer on the substrate includes: forming a first electrode layer on one side of the substrate; forming a preliminary pixel defining layer on a side of the first electrode layer away from the substrate; Patterning the preliminary pixel defining layer to obtain a plurality of first openings, and the remaining preliminary pixel defining layer forms the pixel defining layer; forming a light emitting layer in the first opening; A common electrode is formed on a side of the light emitting layer away from the substrate to obtain the pixel array layer.

13. The method for preparing a display panel according to claim 11, characterized in that: The method further comprises: An encapsulation layer is formed on a side of the pixel array layer facing away from the substrate.

14. A display device, characterized in that: The invention comprises the display panel as claimed in any one of claims 1 to 10.

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