A display panel and its manufacturing method

Abstract

This application provides a display panel and its fabrication method. The display panel includes a substrate, a first electrode layer, a light-emitting functional layer, and a second electrode layer stacked sequentially. The first electrode layer includes multiple first electrode groups, each first electrode group including three first electrode units with different thicknesses. The light-emitting functional layer has a uniform thickness and emits white light. The second electrode layer has a uniform thickness and is a semi-transparent, semi-reflective film. In the display panel provided by this application, the second electrode layer and the three first electrode units with different thicknesses can form three resonant cavities with different cavity lengths. This allows the microcavity effect to be utilized, enabling light from three different wavelength ranges in white light to be emitted from the three resonant cavities with different cavity lengths, thereby achieving full-color display without the need for a color filter with color conversion function. This improves the luminous efficiency of the display panel and simplifies its structure.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a display panel and its manufacturing method. Background Technology

[0002] Organic light-emitting diode (OLED) display panels have advantages over liquid crystal display panels, including being thinner and lighter, having better display effects, higher resolution, wider color gamut, lower power consumption, and the ability to achieve flexible displays. In recent years, market demand for OLED display panels has been expanding.

[0003] Small-sized displays (such as smartwatches, mobile phones, tablets, etc.) mainly use side-by-side (SBS) OLED display devices, where the red, green, and blue light-emitting layers are placed side by side, thus enabling them to emit three colors of light respectively to achieve full color.

[0004] Due to limitations in masking technology, large-size displays (such as televisions) primarily utilize white OLED (WOLED) display devices with stacked light-emitting layers. Multiple light-emitting layers are connected in series via a charge generation layer (CGL) to emit white light. To achieve full-color display, additional color filters (CF) are needed to convert white light into red, green, and blue light. However, this color conversion process inevitably leads to a loss of luminous efficiency, reducing the display quality of the panel. This problem urgently needs to be addressed. Summary of the Invention

[0005] This application provides a display panel and its manufacturing method, which can effectively solve the problem of reduced luminous efficiency caused by the need to set a color filter with color conversion function in existing OLED display panels.

[0006] On one hand, this application provides a display panel, the display panel comprising: a substrate; a first electrode layer disposed on one side of the substrate; a light-emitting functional layer disposed on the side of the first electrode layer facing away from the substrate; and a second electrode layer disposed on the side of the light-emitting functional layer facing away from the substrate; wherein, the first electrode layer comprises a plurality of first electrode groups, each first electrode group comprising three first electrode units with different thicknesses; the light-emitting functional layer has a uniform thickness and emits white light; the second electrode layer has a uniform thickness and is a semi-transparent and semi-reflective film.

[0007] Optionally, the first electrode layer includes a reflective conductive layer and a transparent conductive layer sequentially stacked in a direction away from the substrate. The three first electrode units in each first electrode group are a first electrode unit A, a first electrode unit B, and a first electrode unit C. The reflective conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C all have the same thickness, and the transparent conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C all have different thicknesses.

[0008] Optionally, in each of the first electrode unit groups, the first electrode A unit, the first electrode B unit, and the first electrode C unit are arranged sequentially along a preset direction, and the thicknesses of the transparent conductive layers in the first electrode A unit, the first electrode B unit, and the first electrode C unit are Ha, Hb, and Hc, respectively, with Ha > Hb > Hc.

[0009] Optionally, the distances between the second electrode layer and the reflective conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C are La, Lb, and Lc, respectively, and La > Lb > Lc; the light-emitting functional layer includes a first light-emitting structure layer, a second light-emitting structure layer, and a third light-emitting structure layer, and the light-emitting band intervals of the first light-emitting structure layer, the second light-emitting structure layer, and the third light-emitting structure layer are λ1, λ2, and λ3, respectively, and λ1 > λ2 > λ3; wherein, La:Lb:Lc equals λa:λb:λc, and λa is a light-emitting band value in λ1, λb is a light-emitting band value in λ2, and λc is a light-emitting band value in λ3.

[0010] Optionally, the first light-emitting structure layer emits red light, the second light-emitting structure layer emits green light, and the third light-emitting structure layer emits blue light. The distance between the third light-emitting structure layer and the second electrode layer is less than the distance between the first light-emitting structure layer and the second electrode layer, and the distance between the second light-emitting structure layer and the second electrode layer.

[0011] Optionally, the first light-emitting structure layer, the second light-emitting structure layer, and the third light-emitting structure layer are stacked sequentially in a direction away from the substrate, or the second light-emitting structure layer, the first light-emitting structure layer, and the third light-emitting structure layer are stacked sequentially in a direction away from the substrate.

[0012] Optionally, the third light-emitting structural layer is the only light-emitting structural layer in the light-emitting functional layers that emits blue light.

[0013] Optionally, the light-emitting functional layer further includes a fourth light-emitting structural layer, the fourth light-emitting structural layer emitting blue light, and the light-emitting wavelength range of the fourth light-emitting structural layer being λ4, where λ4 and λ3 do not overlap, and the distance between the fourth light-emitting structural layer and the second electrode layer is less than the distance between the first light-emitting structural layer and the second electrode layer, and the distance between the second light-emitting structural layer and the second electrode layer.

[0014] Optionally, the emission band values ​​in λ4 are all smaller than the emission band values ​​in λ3, and the fourth emission structure layer is disposed on the side of the third emission structure layer away from the substrate.

[0015] On the other hand, this application also provides a method for manufacturing a display panel, the method comprising the following steps:

[0016] A substrate is provided, a first electrode layer is formed on one side of the substrate, and the first electrode is patterned to form a plurality of first electrode groups, each first electrode group including three first electrode units with different thicknesses;

[0017] A light-emitting functional layer is formed on the side of the first electrode layer away from the substrate by vapor deposition. The light-emitting functional layer has a uniform thickness and emits white light.

[0018] A second electrode layer is formed on the side of the light-emitting functional layer away from the substrate by means of vapor deposition. The second electrode layer has a uniform thickness and is a semi-transparent and semi-reflective film.

[0019] This application provides a display panel and its fabrication method. The display panel includes a substrate, a first electrode layer, a light-emitting functional layer, and a second electrode layer stacked sequentially. The first electrode layer includes multiple first electrode groups, each first electrode group including three first electrode units with different thicknesses. The light-emitting functional layer has a uniform thickness and emits white light. The second electrode layer has a uniform thickness and is a semi-transparent and semi-reflective film. In the display panel provided by this application, the second electrode layer and the three first electrode units with different thicknesses can form three resonant cavities with different cavity lengths. This allows the microcavity effect to be utilized, enabling light from three different wavelength ranges in white light to be emitted from the corresponding three resonant cavities with different cavity lengths, thereby achieving full-color display. Furthermore, since the display panel provided by this application can achieve full-color display without the need for a color filter with color conversion function, it can greatly improve the luminous efficiency of the display panel and simplify its structure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a display panel provided in Embodiment 1 of this application.

[0022] Figure 2 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 1 of this application.

[0023] Figure 3 This is a schematic flowchart illustrating the method for preparing a display panel according to Embodiment 1 of this application.

[0024] Figure 4 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 2 of this application.

[0025] Figure 5 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 3 of this application.

[0026] Figure 6 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 4 of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] Substrate 10; First electrode layer 20; Reflective conductive layer 21; Transparent conductive layer 22; First electrode unit A 201a; First electrode unit B 201b; First electrode unit C 201c; Light-emitting functional layer 30; First light-emitting structural layer 31; Second light-emitting structural layer 32; Third light-emitting structural layer 33; Fourth light-emitting structural layer 34; First charge-generating layer 301; Second charge-generating layer 302; Third charge-generating layer 303; Second electrode layer 40 Detailed Implementation

[0029] The technical solutions of the embodiments of this 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 this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0030] The following disclosure provides many different implementations or examples for carrying out different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials. Detailed descriptions are provided below; it should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments.

[0031] Example 1

[0032] Figure 1 This is a schematic diagram of the structure of a display panel provided in Embodiment 1 of this application. Figure 2 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 1 of this application. (Refer to...) Figure 1 and Figure 2 As shown, Embodiment 1 of this application provides a display panel, which includes: a substrate 10, a first electrode layer 20, a light-emitting functional layer 30, and a second electrode layer 40. The first electrode layer 20 is disposed on one side of the substrate 10; the light-emitting functional layer 30 is disposed on the side of the first electrode layer 20 facing away from the substrate 10; and the second electrode layer 40 is disposed on the side of the light-emitting functional layer 30 facing away from the substrate 10. The first electrode layer 20 includes a plurality of first electrode groups, each first electrode group including three first electrode units with different thicknesses. The light-emitting functional layer 30 has a uniform thickness, and the light emitted by the light-emitting functional layer 30 is white. The second electrode layer 40 has a uniform thickness, and the second electrode layer 40 is a semi-transparent and semi-reflective film.

[0033] In the display panel provided in this application, since the light-emitting functional layer 30 emits white light, the light emitted by the light-emitting functional layer 30 includes light in three different wavelength ranges, namely red light, green light and blue light.

[0034] Furthermore, in the display panel provided in this application, since each first electrode group includes three first electrode units with different thicknesses, and the second electrode layer 40 is a semi-transparent and semi-reflective film, the second electrode layer 40 and the three first electrode units with different thicknesses can form three resonant cavities with different cavity lengths. This allows the microcavity effect to be utilized so that light from three different wavelength ranges in white light is emitted from the corresponding three resonant cavities with different cavity lengths, thereby achieving full color. Moreover, since the display panel provided in this application can achieve full color without the need for a color filter with color conversion function, it can greatly improve the luminous efficiency of the display panel and simplify the structure of the display panel.

[0035] In some embodiments of this application, the first electrode layer 20 includes a reflective conductive layer 21 and a transparent conductive layer 22 sequentially stacked in a direction away from the substrate 10. The three first electrode units in each first electrode group are a first electrode unit A 201a, a first electrode unit B 201b, and a first electrode unit C 201c. The reflective conductive layer 21 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c has the same thickness, and the transparent conductive layer 22 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c has different thicknesses.

[0036] Specifically, the reflective conductive layer 21 is used to reflect the emitted light from the light-emitting functional layer 30 and forms the resonant cavity with the second electrode layer 40, which has semi-transparent and semi-reflective properties. Therefore, the cavity length of any resonant cavity is equal to the distance between the reflective conductive layer 21 and the second electrode layer 40.

[0037] Furthermore, since only the transparent conductive layer 22 and the light-emitting functional layer 30 are disposed between the reflective conductive layer 21 and the second electrode layer 40, and the light-emitting functional layer 30 has a uniform thickness, when the thickness of the reflective conductive layer 21 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c is the same, by setting the thickness of the transparent conductive layer 22 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c to be different, the three resonant cavities with different cavity lengths can be formed. Thus, by utilizing the microcavity effect, light from three different wavelength ranges in white light can be emitted from the three resonant cavities with different cavity lengths respectively, thereby achieving full color.

[0038] Optionally, the reflective conductive layer 21 is made of silver, the transparent conductive layer 22 is made of indium tin oxide (ITO) or indium zinc oxide (IZO), and the second electrode layer 40 is made of at least one of magnesium, silver, and aluminum.

[0039] In some embodiments of this application, in each of the first electrode unit groups, the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c are arranged sequentially along a preset direction, and the thicknesses of the transparent conductive layer 22 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c are Ha, Hb, and Hc, respectively, and Ha > Hb > Hc.

[0040] In some embodiments of this application, the distances between the second electrode layer 40 and the reflective conductive layers 21 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c are La, Lb, and Lc, respectively, and La > Lb > Lc; the light-emitting functional layer 30 includes a first light-emitting structure layer 31, a second light-emitting structure layer 32, and a third light-emitting structure layer 33, and the light-emitting band intervals of the first light-emitting structure layer 31, the second light-emitting structure layer 32, and the third light-emitting structure layer 33 are λ1, λ2, and λ3, respectively, and λ1 > λ2 > λ3; wherein, La:Lb:Lc is equal to λa:λb:λc, and λa is a light-emitting band value in λ1, λb is a light-emitting band value in λ2, and λc is a light-emitting band value in λ3.

[0041] Specifically, when considering the microcavity effect, if the viewing angle factor is excluded, the constructive interference condition must be met: L = mλ / 2, where m is a positive integer, L represents the length of the resonant cavity, and λ represents the wavelength of the light emitted from the resonant cavity with the largest amount of light. That is, the length of the resonant cavity is proportional to the wavelength of the light emitted from the resonant cavity with the largest amount of light.

[0042] In the display panel provided in this application, the length of the resonant cavity is equal to the distance between the second electrode layer 40 and the reflective conductive layer 21 in the first electrode unit. Since the distances between the second electrode layer 40 and the reflective conductive layers 21 in the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c are La, Lb, and Lc, respectively, if the wavelengths of the light with the largest emission from the resonant cavity corresponding to the first electrode unit A 201a, the first electrode unit B 201b, and the first electrode unit C 201c are set to λa, λb, and λc, respectively, then according to L = mλ / 2, La:Lb:Lc equals λa:λb:λc.

[0043] This application achieves full-color emission by setting a first light-emitting structure layer 31, a second light-emitting structure layer 32, and a third light-emitting structure layer 33 in the light-emitting functional layer 30, with light emission band intervals of λ1, λ2, and λ3 respectively, and setting λ1 > λ2 > λ3, and λa being a light emission band value in λ1, λb being a light emission band value in λ2, and λc being a light emission band value in λ3. This enables the resonant cavity corresponding to the first electrode unit A 201a to emit light emitted from the first light-emitting structure layer 31; the resonant cavity corresponding to the first electrode unit B 201b to emit light emitted from the second light-emitting structure layer 32; and the resonant cavity corresponding to the first electrode unit C 201c to emit light emitted from the third light-emitting structure layer 33.

[0044] In some embodiments of this application, the first light-emitting structure layer 31 emits red light, the second light-emitting structure layer 32 emits green light, the third light-emitting structure layer 33 emits blue light, and the distance between the third light-emitting structure layer 33 and the second electrode layer 40 is less than the distance between the first light-emitting structure layer 31 and the second electrode layer 40 and the distance between the second light-emitting structure layer 32 and the second electrode layer 40.

[0045] Specifically, the distance between the third light-emitting structure layer 33 and the second electrode layer 40 is smaller than the distance between the first light-emitting structure layer 31 and the second electrode layer 40, and the distance between the second light-emitting structure layer 32 and the second electrode layer 40. That is, the third light-emitting structure layer 33 is closer to the second electrode layer 40 than the first light-emitting structure layer 31 and the second light-emitting structure layer 32.

[0046] Since the third light-emitting structure layer 33 emits blue light, and the material of the blue light-emitting structure layer has better electron transport performance than the materials of the red and green light-emitting structure layers, this application can better help the carrier balance of the first light-emitting structure layer 31 and the second light-emitting structure layer 32 by placing the blue light-emitting third light-emitting structure layer 33 closer to the second electrode layer 40. This can further improve the luminous efficiency of the first light-emitting structure layer 31 and the second light-emitting structure layer 32, thereby further improving the luminous efficiency of the display panel and reducing power consumption.

[0047] Furthermore, since the spectral change rate of blue light is greater than that of red and green light at an oblique viewing angle, blue light attenuates faster at this angle. In the display panel provided in this application, because the third light-emitting structure layer 33, which emits blue light, is positioned closer to the second electrode layer 40, attenuation at an oblique viewing angle can be reduced, making the spectral change rates of blue more compatible with those of red and green, thus better improving viewing angle distortion and enhancing the display quality of the display panel.

[0048] In some embodiments of this application, the first light-emitting structure layer 31, the second light-emitting structure layer 32, and the third light-emitting structure layer 33 are stacked sequentially in a direction away from the substrate 10. That is, the second light-emitting structure layer 32, which emits green light, is disposed between the first light-emitting structure layer 31, which emits red light, and the third light-emitting structure layer 33, which emits blue light.

[0049] Furthermore, the third light-emitting structural layer 33 is the only light-emitting structural layer in the light-emitting functional layer 30 that emits blue light.

[0050] In the display panel provided in this application, since the third light-emitting structure layer 33 is the only light-emitting structure layer in the light-emitting functional layer 30 with a blue light emission color, the structure of the light-emitting functional layer 30 can be simplified, and the manufacturing cost of the display panel can be reduced. Optionally, λ1 is [610nm, 630nm], λa is 620nm; λ2 is [520nm, 540nm], λb is 530nm; λ3 is [450nm, 480nm], and λc is 460nm.

[0051] Further, in the light-emitting functional layer 30, the first light-emitting structural layer 31 includes a hole injection layer, a first hole transport layer, an electron blocking layer, a red organic light-emitting layer, and a first electron transfer layer, which are sequentially stacked in the direction away from the substrate 10; the second light-emitting structural layer 32 includes a second hole transport layer, a green organic light-emitting layer, and a second electron transfer layer, which are sequentially stacked in the direction away from the substrate 10; and the third light-emitting structural layer 33 includes a third hole transport layer, a blue organic light-emitting layer, a hole blocking layer, a third electron transfer layer, and an electron injection layer, which are sequentially stacked in the direction away from the substrate 10.

[0052] Furthermore, in the light-emitting functional layer 30, a first charge-generating layer 301 is provided between the first light-emitting structural layer 31 and the second light-emitting structural layer 32; and a second charge-generating layer 302 is provided between the second light-emitting structure and the third light-emitting structure.

[0053] In some embodiments of this application, the display panel is a top-emitting OLED display panel. Specifically, the light emission direction of the display panel is the same as the direction of the substrate 10 toward the second electrode layer 40, the first electrode layer 20 is an anode layer, and the second electrode layer 40 is a cathode layer. Compared to bottom-emitting OLED display panels, top-emitting OLED display panels have higher light extraction efficiency and lower power consumption.

[0054] In some embodiments of this application, the substrate 10 includes a substrate, a driving circuit layer and a planarization layer stacked sequentially, wherein the first electrode layer 20 is disposed on the side of the planarization layer opposite to the substrate.

[0055] Specifically, the table below compares the parameters of the display panel provided in Embodiment 1 of this application with those of a display panel containing a color filter in related technologies. Here, CE represents current efficiency, and CIE represents the color coordinates. It is evident that the display panel provided in Embodiment 1 of this application significantly improves both current efficiency and color gamut compared to the display panels containing color filters in related technologies.

[0056]

[0057] On the other hand, Embodiment 1 of this application also provides a method for preparing a display panel, which is used to prepare the display panel described in any of the above claims.

[0058] Figure 3 This is a schematic flowchart illustrating the method for fabricating a display panel according to Embodiment 1 of this application. (In conjunction with...) Figures 1-3 As shown, the method for manufacturing the display panel includes steps S01, S02, and S03. Among them,

[0059] Step S01 is as follows: a substrate 10 is provided, a first electrode layer 20 is formed on one side of the substrate 10, and the first electrode is patterned to form a plurality of first electrode groups, each first electrode group including three first electrode units with different thicknesses.

[0060] Step S02 is as follows: using vapor deposition, a full-surface light-emitting functional layer 30 is formed on the side of the first electrode layer 20 away from the substrate 10. The light-emitting functional layer 30 has a uniform thickness and the light-emitting color of the light-emitting functional layer 30 is white.

[0061] Step S03 is as follows: using vapor deposition, a second electrode layer 40 is formed on the side of the light-emitting functional layer 30 away from the substrate 10. The second electrode layer 40 has a uniform thickness and is a semi-transparent and semi-reflective film.

[0062] Example 2

[0063] Figure 4 This is an exploded view of the light-emitting functional layer provided in Embodiment 2 of this application. (Refer to...) Figure 4 As shown in Embodiment 2 of this application, a display panel is provided. The display panel includes: a substrate 10, a first electrode layer 20, a light-emitting functional layer 30, and a second electrode layer 40. The first electrode layer 20 is disposed on one side of the substrate 10; the light-emitting functional layer 30 is disposed on the side of the first electrode layer 20 facing away from the substrate 10; and the second electrode layer 40 is disposed on the side of the light-emitting functional layer 30 facing away from the substrate 10. The first electrode layer 20 includes a plurality of first electrode groups, and each first electrode group includes three first electrode units with different thicknesses. The light-emitting functional layer 30 has a uniform thickness, and the light emitted by the light-emitting functional layer 30 is white. The second electrode layer 40 has a uniform thickness, and the second electrode layer 40 is a semi-transparent and semi-reflective film.

[0064] It should be noted that the display panel provided in Embodiment 2 of this application has a similar structure to the display panel provided in Embodiment 1 of this application. For example, the third light-emitting structure layer 33 is the only light-emitting structure layer in the light-emitting functional layer 30 with a light-emitting color of blue. The same parts will not be described again in Embodiment 2 of this application.

[0065] The difference is that in the light-emitting functional layer 30, the second light-emitting structural layer 32, the first light-emitting structural layer 31, and the third light-emitting structural layer 33 are stacked sequentially in a direction away from the substrate 10. That is, the first light-emitting structural layer 31, which emits red light, is disposed between the second light-emitting structural layer 32, which emits green light, and the third light-emitting structural layer 33, which emits blue light.

[0066] Further, in the light-emitting functional layer 30, the second light-emitting structural layer 32 includes a hole injection layer, a second hole transport layer, an electron blocking layer, a green organic light-emitting layer, and a second electron transfer layer sequentially stacked in the direction away from the substrate 10; the first light-emitting structural layer 31 includes a first hole transport layer, a red organic light-emitting layer, and a first electron transfer layer sequentially stacked in the direction away from the substrate 10; the third light-emitting structural layer 33 includes a third hole transport layer, a blue organic light-emitting layer, a hole blocking layer, a third electron transfer layer, and an electron injection layer sequentially stacked in the direction away from the substrate 10.

[0067] Furthermore, in the light-emitting functional layer 30, a first charge-generating layer 301 is provided between the first light-emitting structural layer 31 and the second light-emitting structural layer 32; and a second charge-generating layer 302 is provided between the second light-emitting structure and the third light-emitting structure.

[0068] On the other hand, Embodiment 2 of this application also provides a method for preparing a display panel, which is used to prepare the display panel described in any of the above claims. The method for preparing the display panel provided in Embodiment 2 of this application is similar to the method for preparing the display panel in Embodiment 1, and will not be described again here.

[0069] Example 3

[0070] Figure 5 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 3 of this application. (Refer to...) Figure 5 As shown in Embodiment 3 of this application, a display panel is provided. The display panel includes: a substrate 10, a first electrode layer 20, a light-emitting functional layer 30, and a second electrode layer 40. The first electrode layer 20 is disposed on one side of the substrate 10; the light-emitting functional layer 30 is disposed on the side of the first electrode layer 20 facing away from the substrate 10; and the second electrode layer 40 is disposed on the side of the light-emitting functional layer 30 facing away from the substrate 10. The first electrode layer 20 includes a plurality of first electrode groups, and each first electrode group includes three first electrode units with different thicknesses. The light-emitting functional layer 30 has a uniform thickness and emits white light. The second electrode layer 40 has a uniform thickness and is a semi-transparent and semi-reflective film.

[0071] It should be noted that the display panel provided in Embodiment 3 of this application has a similar structure to the display panel provided in Embodiment 1 of this application. For example, the first light-emitting structure layer 31, the second light-emitting structure layer 32 and the third light-emitting structure layer 33 in the light-emitting functional layer 30 are stacked sequentially in the direction away from the substrate 10. The same parts will not be described again in Embodiment 3 of this application.

[0072] The difference is that the light-emitting functional layer 30 also includes a fourth light-emitting structure layer 34, the light-emitting color of the fourth light-emitting structure layer 34 is blue, and the light-emitting wavelength range of the fourth light-emitting structure layer 34 is λ4, λ4 and λ3 do not overlap, and the distance between the fourth light-emitting structure layer 34 and the second electrode layer 40 is smaller than the distance between the first light-emitting structure layer 31 and the second electrode layer 40 and the distance between the second light-emitting structure layer 32 and the second electrode layer 40.

[0073] Because the spectral variation rate of blue light is greater than that of red and green light at an oblique viewing angle, blue light attenuates faster at this angle. The display panel provided in this application uses a stacked combination of two blue light-emitting structures in different emission wavelength ranges, which effectively reduces the spectral variation rate of blue light at an oblique viewing angle, making the spectral variation rates of blue more compatible with those of red and green, thereby better improving viewing angle distortion.

[0074] In some embodiments of this application, the emission band values ​​in λ4 are all smaller than the emission band values ​​in λ3, and the fourth emission structure layer 34 is disposed on the side of the third emission structure layer 33 away from the substrate 10.

[0075] In the display panel provided in this application, since the emission band range of the fourth light-emitting structure layer 34 is λ4, and the emission band values ​​in λ4 are all smaller than the emission band values ​​in λ3, the blue light emitted by the third light-emitting structure layer 33 has a longer wavelength, while the blue light emitted by the fourth light-emitting structure layer 34 has a shorter wavelength. Because the fourth light-emitting structure layer 34 is disposed on the side of the third light-emitting structure layer 33 facing away from the substrate 10, the shorter wavelength blue light emitted by the fourth light-emitting structure layer 34 can be irradiated by the longer wavelength blue light emitted by the third light-emitting structure layer 33, thereby improving the blue color purity and thus enhancing the color gamut of the display panel. Optionally, the luminous efficiency of the material of the third light-emitting structure layer 33 is greater than the luminous efficiency of the material of the fourth light-emitting structure layer 34.

[0076] Furthermore, the emission bands of λ1, λ2, λ3, and λ4 are [610nm, 630nm], [520nm, 540nm], [460nm, 480nm], and [440nm, 460nm], respectively; where λa is 620nm; λb is 530nm; and λc is 460nm.

[0077] Further, in the light-emitting functional layer 30, the first light-emitting structural layer 31 includes a hole injection layer, a first hole transport layer, an electron blocking layer, a red organic light-emitting layer, and a first electron transfer layer, which are sequentially stacked in the direction away from the substrate 10; the second light-emitting structural layer 32 includes a second hole transport layer, a green organic light-emitting layer, and a second electron transfer layer, which are sequentially stacked in the direction away from the substrate 10; the third light-emitting structural layer 33 includes a third hole transport layer, a first blue organic light-emitting layer, and a third electron transfer layer, which are sequentially stacked in the direction away from the substrate 10; and the fourth light-emitting structural layer 34 includes a fourth hole transport layer, a second blue organic light-emitting layer, a hole blocking layer, a fourth electron transfer layer, and an electron injection layer, which are sequentially stacked in the direction away from the substrate 10.

[0078] Furthermore, in the light-emitting functional layer 30, a first charge-generating layer 301 is provided between the first light-emitting structure layer 31 and the second light-emitting structure layer 32; a second charge-generating layer 302 is provided between the second light-emitting structure and the third light-emitting structure; and a third charge-generating layer 303 is provided between the third light-emitting structure and the fourth light-emitting structure.

[0079] Specifically, the table below compares the parameters of the display panel provided in Embodiment 3 of this application with those of a display panel containing a color filter in related technologies. Here, CE represents current efficiency, and CIE represents the color coordinates. It can be seen that the display panel provided in Embodiment 3 of this application significantly improves both current efficiency and color gamut compared to the display panel containing a color filter in related technologies; and compared to Embodiment 1, the current efficiency of blue light in the display panel provided in Embodiment 3 of this application is significantly improved.

[0080]

[0081] It should be noted that, in other embodiments of this application, the fourth light-emitting structure layer 34 may also be disposed on the side of the third light-emitting structure layer 33 facing the substrate 10.

[0082] On the other hand, Embodiment 3 of this application also provides a method for preparing a display panel, which is used to prepare the display panel described in any of the above claims. The method for preparing the display panel provided in Embodiment 3 of this application is similar to the method for preparing the display panel in Embodiment 1, and will not be described again here.

[0083] Example 4

[0084] Figure 6 This is an exploded view of the structure of the light-emitting functional layer provided in Embodiment 4 of this application. (Refer to...) Figure 6As shown, Embodiment 4 of this application provides a display panel, which includes: a substrate 10, a first electrode layer 20, a light-emitting functional layer 30, and a second electrode layer 40. The first electrode layer 20 is disposed on one side of the substrate 10; the light-emitting functional layer 30 is disposed on the side of the first electrode layer 20 facing away from the substrate 10; and the second electrode layer 40 is disposed on the side of the light-emitting functional layer 30 facing away from the substrate 10. The first electrode layer 20 includes a plurality of first electrode groups, each first electrode group including three first electrode units with different thicknesses. The light-emitting functional layer 30 has a uniform thickness and emits white light. The second electrode layer 40 has a uniform thickness and is a semi-transparent, semi-reflective film.

[0085] It should be noted that the display panel provided in Embodiment 4 of this application has a similar structure to the display panel provided in Embodiment 3 of this application, and the same parts will not be described again in Embodiment 4 of this application.

[0086] The difference is that in the light-emitting functional layer 30, the second light-emitting structural layer 32, the first light-emitting structural layer 31, and the third light-emitting structural layer 33 are stacked sequentially in a direction away from the substrate 10. That is, the first light-emitting structural layer 31, which emits red light, is disposed between the second light-emitting structural layer 32, which emits green light, and the third light-emitting structural layer 33, which emits blue light.

[0087] Further, in the light-emitting functional layer 30, the second light-emitting structural layer 32 includes a hole injection layer, a second hole transport layer, an electron blocking layer, a green organic light-emitting layer, and a second electron transfer layer sequentially stacked in the direction away from the substrate 10; the first light-emitting structural layer 31 includes a first hole transport layer, a red organic light-emitting layer, and a first electron transfer layer sequentially stacked in the direction away from the substrate 10; the third light-emitting structural layer 33 includes a third hole transport layer, a first blue organic light-emitting layer, and a third electron transfer layer sequentially stacked in the direction away from the substrate 10; and the fourth light-emitting structural layer 34 includes a fourth hole transport layer, a second blue organic light-emitting layer, a hole blocking layer, a fourth electron transfer layer, and an electron injection layer sequentially stacked in the direction away from the substrate 10.

[0088] Furthermore, in the light-emitting functional layer 30, a first charge-generating layer 301 is provided between the first light-emitting structure layer 31 and the second light-emitting structure layer 32; a second charge-generating layer 302 is provided between the second light-emitting structure and the third light-emitting structure; and a third charge-generating layer 303 is provided between the third light-emitting structure and the fourth light-emitting structure.

[0089] On the other hand, Embodiment 4 of this application also provides a method for preparing a display panel, which is used to prepare the display panel described in any of the above claims. The method for preparing the display panel provided in Embodiment 4 of this application is similar to the method for preparing the display panel in Embodiment 1, and will not be described again here.

[0090] In summary, this application provides a display panel and its fabrication method. The display panel includes a substrate, a first electrode layer, a light-emitting functional layer, and a second electrode layer stacked sequentially. The first electrode layer includes multiple first electrode groups, each of which includes three first electrode units with different thicknesses. The light-emitting functional layer has a uniform thickness and emits white light. The second electrode layer has a uniform thickness and is a semi-transparent, semi-reflective film. In the display panel provided by this application, the second electrode layer and the three first electrode units with different thicknesses can form three resonant cavities with different cavity lengths. This allows the microcavity effect to be utilized, enabling light from three different wavelength ranges in white light to be emitted from the three resonant cavities with different cavity lengths, thereby achieving full-color display without the need for a color filter with color conversion function. This improves the luminous efficiency of the display panel and simplifies its structure.

[0091] The above provides a detailed description of a display panel and its preparation method according to the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A display panel, characterized in that, The display panel includes: Substrate; A first electrode layer is disposed on one side of the substrate; A light-emitting functional layer is disposed on the side of the first electrode layer facing away from the substrate. The light-emitting functional layer is a continuous film layer covering the entire surface. The light-emitting functional layer includes a first light-emitting structural layer, a second light-emitting structural layer, a third light-emitting structural layer, and a fourth light-emitting structural layer. The fourth light-emitting structural layer is disposed on the side of the third light-emitting structural layer facing away from the substrate. The light-emitting color of the third light-emitting structural layer and the fourth light-emitting structural layer is blue. The light-emitting wavelength range of the third light-emitting structural layer is λ3, and the light-emitting wavelength range of the fourth light-emitting structural layer is λ4. The light-emitting wavelength values ​​in λ4 are all smaller than the light-emitting wavelength values ​​in λ3. The luminous efficiency of the material in the third light-emitting structural layer is greater than that of the material in the fourth light-emitting structural layer. The second electrode layer is disposed on the side of the light-emitting functional layer opposite to the substrate; The first electrode layer includes multiple first electrode groups, each first electrode group including three first electrode units with different thicknesses; the light-emitting functional layer has a uniform thickness and the light-emitting color of the light-emitting functional layer is white; the second electrode layer has a uniform thickness and the second electrode layer is a semi-transparent and semi-reflective film.

2. The display panel according to claim 1, characterized in that, The first electrode layer includes a reflective conductive layer and a transparent conductive layer stacked sequentially in a direction away from the substrate. The three first electrode units in each first electrode group are a first electrode unit A, a first electrode unit B, and a first electrode unit C. The reflective conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C have the same thickness, and the transparent conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C have different thicknesses.

3. The display panel according to claim 2, characterized in that, In each of the first electrode groups, the first electrode unit A, the first electrode unit B, and the first electrode unit C are arranged sequentially along a preset direction. The thicknesses of the transparent conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C are Ha, Hb, and Hc, respectively, and Ha > Hb > Hc.

4. The display panel according to claim 3, characterized in that, The distances between the second electrode layer and the reflective conductive layers in the first electrode unit A, the first electrode unit B, and the first electrode unit C are La, Lb, and Lc, respectively, and La > Lb > Lc; the emission band ranges of the first light-emitting structure layer, the second light-emitting structure layer, and the third light-emitting structure layer are λ1, λ2, and λ3, respectively, and λ1 > λ2 > λ3. Wherein, La:Lb:Lc equals λa:λb:λc, and λa is a light emission band value in λ1, λb is a light emission band value in λ2, and λc is a light emission band value in λ3.

5. The display panel according to claim 4, characterized in that, The first light-emitting structure layer emits red light, and the second light-emitting structure layer emits green light.

6. The display panel according to claim 5, characterized in that, The first light-emitting structure layer, the second light-emitting structure layer, and the third light-emitting structure layer are stacked sequentially along a direction away from the substrate. Alternatively, the second light-emitting structure layer, the first light-emitting structure layer, and the third light-emitting structure layer are stacked sequentially in a direction away from the substrate.

7. The display panel according to claim 6, characterized in that, The third light-emitting structural layer is the only light-emitting structural layer in the light-emitting functional layers that emits blue light.

8. A method for manufacturing a display panel, characterized in that, The method for manufacturing the display panel includes the following steps: A substrate is provided, a first electrode layer is formed on one side of the substrate, and the first electrode layer is patterned to form a plurality of first electrode groups, each first electrode group including three first electrode units with different thicknesses; A continuous light-emitting functional layer is formed on the side of the first electrode layer away from the substrate using vapor deposition. The light-emitting functional layer has a uniform thickness and emits white light. The light-emitting functional layer includes a first light-emitting structural layer, a second light-emitting structural layer, a third light-emitting structural layer, and a fourth light-emitting structural layer. The fourth light-emitting structural layer is disposed on the side of the third light-emitting structural layer away from the substrate. The third and fourth light-emitting structural layers emit blue light. The emission band range of the third light-emitting structural layer is λ3, and the emission band range of the fourth light-emitting structural layer is λ4. The emission band values ​​in λ4 are all smaller than the emission band values ​​in λ3. The luminous efficiency of the material in the third light-emitting structural layer is greater than that of the material in the fourth light-emitting structural layer. A second electrode layer is formed on the side of the light-emitting functional layer away from the substrate by means of vapor deposition. The second electrode layer has a uniform thickness and is a semi-transparent and semi-reflective film.

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