Display panel, preparation method thereof and display device

Abstract

The present disclosure provides a display panel, a preparation method thereof and a display device. The display panel comprises a substrate and a light-emitting functional layer. The substrate comprises a first display area and a second display area at least partially surrounding the first display area. The first display area is used for image display and light transmission, and the second display area is used for image display. The light-emitting functional layer is located on one side of the substrate and comprises an organic electroluminescent layer. The first display area and the second display area each comprise a plurality of sub-pixels emitting light of different colors. The organic electroluminescent layers of the sub-pixels located in the first display area emit light of the same color. The organic electroluminescent layers of each sub-pixel in the first display area emit light of the same color, i.e. the organic electroluminescent layers of each sub-pixel in the first display area are formed of the same material, so that each sub-pixel in the first display area has the same turn-on voltage, thereby solving the color deviation problem of low gray scale white picture.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular, to a display panel, a preparation method thereof and a display device. BACKGROUND

[0002] With the development of display technology, full screen or narrow frame products have gradually become the development trend of display products due to their large screen ratio and ultra-narrow frame. For products such as smart terminals, it is usually necessary to set front-facing cameras, fingerprint sensors or light sensors and the like. In order to improve the screen ratio, full screen or narrow frame products usually adopt a full display with camera (FDC) or an under-display fingerprint technology to place the camera and the like in a camera area (UDC) under the display substrate. The camera area under the display not only has a certain transmittance, but also has a display function. In the related art, there is a white picture low gray scale color cast problem in the FDC area.

[0003] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0004] The purpose of the present disclosure is to overcome the shortcomings of the prior art, and to provide a display panel, a preparation method thereof and a display device.

[0005] According to one aspect of the present disclosure, a display panel is provided, comprising: a substrate, the substrate comprising a first display area and a second display area at least partially surrounding the first display area, the first display area being used for image display and light transmission, and the second display area being used for image display; a light-emitting functional layer located on one side of the substrate, the light-emitting functional layer comprising an organic electroluminescent layer; wherein the first display area and the second display area each comprise a plurality of sub-pixels emitting different color light, and the organic electroluminescent layers of the sub-pixels located in the first display area emit light of the same color.

[0006] In an exemplary embodiment of the present disclosure, the plurality of sub-pixels in the first display area comprises at least a first sub-pixel and a second sub-pixel, the light emitted by the first sub-pixel is of a different color from the light emitted by the second sub-pixel; the organic electroluminescent layer of the first sub-pixel and the organic electroluminescent layer of the second sub-pixel are each formed of a first light-emitting material, the light-emitting color of the first light-emitting material is the same as the color of the light emitted by the first sub-pixel, and the light-emitting efficiency of the first light-emitting material is greater than the light-emitting efficiency of a second light-emitting material, and the light-emitting color of the second light-emitting material is the same as the color of the light emitted by the second sub-pixel.

[0007] In the example embodiment of the present disclosure, the plurality of sub-pixels in the first display area include R sub-pixels emitting red light, G sub-pixels emitting green light, and B sub-pixels emitting blue light; the organic electroluminescent layers of the sub-pixels in the first display area all emit green light.

[0008] In the example embodiment of the present disclosure, in the first display area, the thickness of the organic electroluminescent layer of the R sub-pixel, the thickness of the organic electroluminescent layer of the G sub-pixel, and the thickness of the organic electroluminescent layer of the B sub-pixel decrease in turn.

[0009] In the example embodiment of the present disclosure, the thicknesses of the organic electroluminescent layers of the sub-pixels in the first display area are the same.

[0010] In the example embodiment of the present disclosure, the light-emitting functional layer further includes: a first organic layer between the organic electroluminescent layer and the substrate; a light-emitting adjustment layer between the organic electroluminescent layer and the first organic layer; wherein, in the first display area, the thickness of the organic electroluminescent layer of each sub-pixel is d1, the thickness of the light-emitting adjustment layer of the B sub-pixel is d2, d1 / d2 is greater than or equal to 3 and less than or equal to 9.

[0011] In the example embodiment of the present disclosure, the pixel resolution of the first display area is the same as the pixel resolution of the second display area.

[0012] In the example embodiment of the present disclosure, in the first display area, the aperture ratio of the R sub-pixel is k1, the aperture ratio of the G sub-pixel is k2, and the aperture ratio of the B sub-pixel is k3, k1 / k2 is greater than or equal to 1 / 2 and less than or equal to 1, and k1 / k3 is greater than or equal to 1 / 4 and less than or equal to 3 / 4.

[0013] In the example embodiment of the present disclosure, the light-emitting functional layer further includes: a first organic layer between the organic electroluminescent layer and the substrate; a light-emitting adjustment layer between the organic electroluminescent layer and the first organic layer; a second organic layer on the side of the organic electroluminescent layer away from the substrate and covering the organic electroluminescent layer; the display panel further includes: a first electrode layer between the substrate and the first organic layer; a second electrode layer on the side of the second organic layer away from the substrate and covering the second organic layer; wherein, the first electrode layer, the first organic layer, the light-emitting adjustment layer, the organic electroluminescent layer, the second organic layer, and the second electrode layer are stacked to form a microcavity of the sub-pixel, and in the first display area, the microcavity length of the R sub-pixel, the microcavity length of the G sub-pixel, and the microcavity length of the B sub-pixel decrease in turn.

[0014] In the exemplary embodiments of the present disclosure, the microcavity length of the R sub-pixel in the first display area is greater than the microcavity length of the R sub-pixel in the second display area, the microcavity length of the G sub-pixel in the first display area is the same as the microcavity length of the B sub-pixel in the second display area, and the microcavity length of the B sub-pixel in the first display area is greater than the microcavity length of the B sub-pixel in the second display area.

[0015] In the exemplary embodiments of the present disclosure, in the first display area, the microcavity length of the R sub-pixel is greater than or equal to 2700 nm and less than or equal to 2900 nm, and the microcavity length of the B sub-pixel is greater than or equal to 1900 nm and less than or equal to 2100 nm.

[0016] In the exemplary embodiments of the present disclosure, in the first display area, the peak wavelength of the emission spectrum curve of the R sub-pixel is located in the range of 585-605 nm, and the peak wavelength of the emission spectrum curve of the B sub-pixel is located in the range of 505-525 nm.

[0017] In the exemplary embodiments of the present disclosure, in the first display area, the y coordinate value of the CIE color coordinate of the B sub-pixel is less than or equal to 0.075.

[0018] According to the second aspect of the present disclosure, a display panel preparation method is further provided for preparing the display panel of any of the embodiments of the present disclosure, and the method comprises: providing a substrate, wherein the substrate has a first display area and a second display area, the first display area is used for image display and light transmission, the second display area is used for image display, and the second display area at least partially surrounds the first display area, and the first display area and the second display area both comprise a plurality of sub-pixels emitting light of different colors; forming a light-emitting functional layer on one side of the substrate by using an evaporation process, wherein the light-emitting functional layer comprises an organic electroluminescent layer, and the light-emitting colors of the organic electroluminescent layers of the sub-pixels located in the first display area are the same.

[0019] In the example embodiment of the present disclosure, the forming the light-emitting functional layer on one side of the substrate by using the evaporation process comprises: evaporating a first organic layer on the first display area and the second display area on the substrate; evaporating an array-distributed R light-emitting adjusting layer, a G light-emitting adjusting layer and a B light-emitting adjusting layer on the first organic layer; evaporating a second light-emitting material on the R light-emitting adjusting layer, a first light-emitting material on the G light-emitting adjusting layer and a third light-emitting material on the B light-emitting adjusting layer of the second display area to form an organic electroluminescent layer of the second display area, and evaporating the first light-emitting material on the R light-emitting adjusting layer, the G light-emitting adjusting layer and the B light-emitting adjusting layer of the first display area to form an organic electroluminescent layer of the first display area, wherein the light-emitting efficiency of the first light-emitting material is greater than the light-emitting efficiency of the second light-emitting material and the light-emitting efficiency of the third light-emitting material; and evaporating a second organic layer on the organic electroluminescent layer.

[0020] In the example embodiment of the present disclosure, before the forming the light-emitting functional layer on one side of the substrate by using the evaporation process, the method further comprises: forming a first electrode layer and a pixel definition layer on the first display area and the second display area on the substrate; and patterning the pixel definition layer by using a patterning process to form a pixel definition structure, wherein adjacent pixel definition structures define the sub-pixel.

[0021] In the example embodiment of the present disclosure, after the forming the light-emitting functional layer on one side of the substrate by using the evaporation process, the method further comprises: evaporating a second electrode layer on the light-emitting functional layer; and forming a color film layer on the second electrode layer by using an encapsulation process, wherein the color film layer comprises a light filtering part corresponding to the sub-pixel, and the light filtering part is used for transmitting light of a corresponding color.

[0022] According to a third aspect of the present disclosure, a display device is also provided, comprising the display panel of any of the embodiments of the present disclosure.

[0023] The display panel provided by the present disclosure, the first display area and the second display area both comprise sub-pixels emitting light of different colors, the organic electroluminescent layers of each sub-pixel in the first display area emit light of the same color, i.e., the organic electroluminescent layers of each sub-pixel in the first display area are formed by the same material, so that each sub-pixel in the first display area has the same turn-on voltage, and the problem of color deviation of low gray scale white picture is solved.

[0024] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the present disclosure. It is apparent that the drawing in the following description merely show some embodiments of the present disclosure and, to one of ordinary skill in the art, other drawings can be obtained from these drawings without any creative work.

[0026] Figure 1 A structural schematic diagram of a display panel according to an embodiment of the present disclosure;

[0027] Figure 2 A structural schematic diagram of a display panel according to an embodiment of the present disclosure; Figure 1 A structural schematic diagram of a pixel unit in a first display area and a second display area in a cross-sectional view along the AA direction;

[0028] Figure 3 A luminescence spectrum curve of an R sub-pixel according to an embodiment of the present disclosure;

[0029] Figure 4 A luminescence spectrum curve of a G sub-pixel according to an embodiment of the present disclosure;

[0030] Figure 5 A luminescence spectrum curve of a B sub-pixel according to an embodiment of the present disclosure;

[0031] Figure 6 A structural schematic diagram of forming a first organic layer in a preparation process according to an embodiment of the present disclosure;

[0032] Figure 7 A structural schematic diagram of forming a luminescence adjusting layer in a preparation process according to an embodiment of the present disclosure;

[0033] Figure 8 A structural schematic diagram of forming a luminescence layer in a preparation process according to an embodiment of the present disclosure;

[0034] Figure 9 A structural schematic diagram of forming a second organic layer in a preparation process according to an embodiment of the present disclosure;

[0035] Figure 10 A structural schematic diagram of a pixel unit formed in a preparation process according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example implementations to those skilled in the art. Like reference numerals refer to like elements throughout the figures, and detailed descriptions of well-known structures and processes are omitted so as not to obscure the description of the example implementations. Further, the drawings are diagrammatic and are not necessarily to scale.

[0037] Figure 1 A structural schematic diagram of a display panel according to an embodiment of the present disclosure, Figure 2 A structural schematic diagram of a display panel according to an embodiment of the present disclosure, Figure 1 A structural schematic diagram of a display panel according to an embodiment of the present disclosure, Figure 1 A structural schematic diagram of a display panel according to an embodiment of the present disclosure, Figure 2 As shown in the drawings, in the present example embodiment, the display panel can include a substrate 10 and a light-emitting functional layer 20. The substrate 10 can include a first display area 100 and a second display area 200 at least partially surrounding the first display area 100. The first display area 100 is configured to display images and transmit light, and the second display area 200 is configured to display images. The light-emitting functional layer 20 is located on one side of the substrate 10, and the light-emitting functional layer 20 can include an organic electroluminescent layer EML. The first display area 100 and the second display area 200 each include a plurality of sub-pixels emitting different colors of light. The organic electroluminescent layers EML of the sub-pixels in the first display area 100 emit the same color of light.

[0038] The display panel provided by the present disclosure includes the first display area 100 and the second display area 200 each including sub-pixels emitting different colors of light. The organic electroluminescent layers EML of the sub-pixels in the first display area 100 emit the same color of light, i.e., the organic electroluminescent layers EML of the sub-pixels in the first display area 100 are formed of the same material, so that the sub-pixels in the first display area 100 have the same turn-on voltage, thereby solving the color deviation problem of low gray-scale white pictures.

[0039] As shown in the drawings, in the present example embodiment, the display panel can include a substrate 10 and a light-emitting functional layer 20. The substrate 10 can include a first display area 100 and a second display area 200 at least partially surrounding the first display area 100. The first display area 100 is configured to display images and transmit light, and the second display area 200 is configured to display images. The light-emitting functional layer 20 is located on one side of the substrate 10, and the light-emitting functional layer 20 can include an organic electroluminescent layer EML. The first display area 100 and the second display area 200 each include a plurality of sub-pixels emitting different colors of light. The organic electroluminescent layers EML of the sub-pixels in the first display area 100 emit the same color of light. Figure 1As shown, in an exemplary embodiment, the first display area 100 can be an FDC area, and the second display area 200 can be a normal display area. The position of the first display area 100 in the second display area 200 is not limited; it can be located at the upper or lower part of the second display area 200, or at the edge of the second display area 200. In this exemplary embodiment, in a plane parallel to the display substrate, the shape of the first display area 100 can be any one or more of the following: square, rectangle, polygon, circle, and ellipse, etc. Optical devices such as fingerprint recognition devices, camera devices, or 3D imaging optical sensors can be placed in the first display area 100. When the shape of the first display area 100 is circular, the diameter of the circle can be approximately 3mm to 4mm; when the shape of the first display area 100 is rectangular, the side length of the rectangle can be approximately 3mm to 4mm. This disclosure does not impose any limitations on this.

[0040] The organic electroluminescent layer (EML) of each sub-pixel in the first display area 100 emits light of the same color, which can be understood as the organic electroluminescent layer (EML) of each sub-pixel in the first display area 100 being formed of the same light-emitting material. For example, the first display area 100 may include an R sub-pixel emitting red light, a G sub-pixel emitting green light, and a B sub-pixel emitting blue light. The organic electroluminescent layer (EML) of the R, G, and B sub-pixels in the first display area 100 can then be formed of a green-emitting, red-emitting, or blue-emitting material. Since the organic electroluminescent layer (EML) of each sub-pixel in the first display area 100 is formed of the same light-emitting material, each sub-pixel in the first display area 100 has the same activation voltage, solving the problem of color bleeding in white images at low grayscale levels and improving the display quality of the first display area 100.

[0041] like Figure 2 As shown in this exemplary embodiment, the organic electroluminescent layer (EML) of each sub-pixel in the first display area 100 is formed of the same material, thereby reducing the number of wirings and the line spacing in the first display area 100, i.e., reducing the space occupied by the wiring, and thus reducing the overall size of the first display area 100. For example, when the orthographic projection of the first display area onto the substrate is circular, the aperture of the first display area can be 3mm to 4mm.

[0042] It should be understood that, in this exemplary embodiment, the display panel may further include a first electrode layer 30, a pixel definition layer (PDL), a second electrode layer 40, and a color filter layer (…). Figure 2The first electrode layer 30 can include a plurality of first electrodes which are spaced apart from each other, and each first electrode has a projection on the substrate which is located in the pixel region and is connected to the pixel circuit. One first electrode is connected to one pixel circuit. The pixel definition layer PDL and the first electrode layer 30 are arranged on the same side of the substrate, and each first electrode is exposed. The pixel definition layer PDL includes a plurality of pixel defining structures which are spaced apart from each other along the arrangement direction of the pixels, and two adjacent pixel defining structures define one sub-pixel. It should be understood that, Figure 2 The two adjacent sub-pixels are separated by one pixel defining structure, which is not shown in the figure. The light-emitting functional layer 20 covers the pixel definition layer PDL and the first electrode layer 30. The second electrode layer covers the light-emitting functional layer 20. The second electrode layer 40 can include a second electrode, and the second electrode can be a cathode. Correspondingly, the first electrode can be an anode. Of course, in other embodiments, the second electrode can also be an anode, and the first electrode can be a cathode, which is not limited in the present disclosure.

[0043] The color filter layer has a plurality of filter parts, one sub-pixel includes one filter part, and a plurality of sub-pixels constitute one pixel unit. The colors of the light transmitted by different filter parts can be different, so that the light-emitting colors of different sub-pixels can be different. The specific structure of the color filter layer is not described in detail here. The same pixel unit includes a plurality of sub-pixels with different colors, for example, a pixel unit can include three sub-pixels with red, green and blue light-emitting colors. Thus, color display can be realized by a plurality of pixel units.

[0044] For example, the organic electroluminescent layer EML in the first display area 100 emits green light. The green light emitted by the organic electroluminescent layer EML of the R sub-pixel can be red-shifted after being adjusted by the microcavity, and then the R sub-pixel finally emits red light through the filtering effect of the color filter layer located on the path of the emitted light. Similarly, the B sub-pixel can also emit blue light through the microcavity adjustment and the filtering effect.

[0045] It should be understood that in the present exemplary embodiment, the second display area 200 can have the same structure as the AA area of the existing display panel, which is not described here.

[0046] In the related art, in order to improve the display quality of the FDC area, the FDC area and the normal display area can have the same resolution. In order to take into account the light transmittance, the light-emitting area of the FDC area is very small. Because the OLED is driven by current, the reduction of the light-emitting area requires a high current to achieve the same brightness as the normal display area, which causes the FDC area to have a shorter service life than the normal display area, thereby affecting the display quality of the FDC area. The present disclosure improves the organic electroluminescent layer EML of the FDC area of the display panel to solve the above problems. The present disclosure will be further described below with reference to the accompanying drawings, and in the absence of special description, the first light-emitting material of the present disclosure emits green light, the second light-emitting material emits red light, and the third light-emitting material emits blue light.

[0047] In the present exemplary embodiment, the organic electroluminescent layer EML in the first display area 100 can be formed by using a light-emitting material with high luminous efficiency to improve the service life of each sub-pixel in the first display area 100. For example, the pixel unit of the first display area 100 includes an R sub-pixel emitting red light, a G sub-pixel emitting green light, and a B sub-pixel emitting blue light. The organic electroluminescent layer EML in the first display area 100 can be formed by using a first light-emitting material. It should be understood that in other exemplary embodiments, the organic electroluminescent layer of each sub-pixel in the first display area 100 can also emit light of different colors. For example, in the first display area 100, the organic electroluminescent layer of the R sub-pixel and the organic electroluminescent layer of the B sub-pixel are both formed by a second light-emitting material, and the organic electroluminescent layer of the G sub-pixel is formed by a first light-emitting material. Alternatively, the organic electroluminescent layer of the R sub-pixel and the organic electroluminescent layer of the G sub-pixel are both formed by a first light-emitting material, and the organic electroluminescent layer of the B sub-pixel is formed by a second light-emitting material. The above schemes can improve the luminous efficiency of at least part of the sub-pixels to some extent, thereby helping to improve the service life of at least part of the sub-pixels, which are all within the protection scope of the present disclosure.

[0048] The present disclosure only takes the first display area 100 including R, G, and B sub-pixels and the organic electroluminescent layer EML of the first display area 100 being formed by a first light-emitting material emitting green light as an example to exemplarily describe the structure and working principle of the first display area 100.

[0049] In the present exemplary embodiment, the light emitting efficiency of the light emitting material can be understood as the light emitting intensity of the light emitting material when using a unit intensity of driving current. The light emitting efficiency of the first light emitting material being greater than the light emitting efficiency of the second light emitting material can be understood as the light emitting intensity of the first organic electroluminescent material being greater than the light emitting intensity of the second organic electroluminescent material when the driving current is the same. By using the light emitting material with high light emitting efficiency to form the organic electroluminescent layer EML in the first display area 100, the overall light emitting efficiency of each sub-pixel in the first display area 100 can be improved, so that when the aperture ratio of the first display area 100 is reduced to improve the light transmittance of the first display area 100, the driving current for the organic electroluminescent layer EML does not need to be increased, thereby the life of each sub-pixel in the first display area 100 can be improved, and the life and light emitting efficiency of the first display area 100 can be balanced.

[0050] As shown in Figure 2 In the present exemplary embodiment, the light emitting functional layer 20 can further include a first organic layer 210 and a second organic layer 220 in addition to the organic electroluminescent layer EML. The first organic layer 210 is located between the organic electroluminescent layer EML and the substrate, and the second organic layer 220 is located on the side of the organic electroluminescent layer EML away from the substrate. The first organic layer 210 can include a hole injection layer HIL and a hole transport layer HTL, and the second organic layer 220 can include an electron transport layer ETL and an electron injection layer EIL. The specific structures of the hole injection layer HIL, the hole transport layer HTL, the electron transport layer ETL, and the electron injection layer EIL are not described in detail here. Adjacent light emitting functional layers can share one or more of the hole injection layer HIL, the hole transport layer HTL, the electron transport layer ETL, and the electron injection layer EIL.

[0051] As shown in Figure 2As shown in this exemplary embodiment, the light-emitting functional layer 20 may further include a hole blocking layer HBL and a light-emitting modulation layer 230. The hole blocking layer HBL is located between the second organic layer 220 and the organic electroluminescent layer EML of the corresponding sub-pixel. The specific structure of the hole blocking layer HBL will not be detailed here. Adjacent light-emitting functional layers 20 may share the hole blocking layer HBL. The light-emitting modulation layer 230 is located between the hole transport layer HTL and the organic electroluminescent layer EML of the corresponding sub-pixel. The light-emitting modulation layer 230 corresponds one-to-one with each sub-pixel and can be used to adjust the microcavity length of each sub-pixel, thereby adjusting the peak wavelength of the spectrum of light emitted from each sub-pixel. The light-emitting modulation layer 230 of the R sub-pixel may be formed of a second light-emitting material that emits red light, the light-emitting modulation layer 230 of the G sub-pixel may be formed of a first light-emitting material that emits green light, and the light-emitting modulation layer 230 of the B sub-pixel may be formed of a third light-emitting material that emits blue light. The thickness of the light emission adjustment layer 230 of the R sub-pixel can be greater than the thickness of the light emission adjustment layer 230 of the G sub-pixel, and the thickness of the light emission adjustment layer 230 of the G sub-pixel is greater than the thickness of the light emission adjustment layer 230 of the B sub-pixel. That is, the thickness of the light emission adjustment layer 230 of the B sub-pixel is the smallest, and the thickness of the light emission adjustment layer 230 of the R sub-pixel is the largest. This allows the microcavity length of the B sub-pixel to be minimized, resulting in a blue shift in the emission spectrum of the organic electroluminescent layer EML, and the microcavity length of the R sub-pixel to be maximized, resulting in a red shift in the emission spectrum of the organic electroluminescent layer EML.

[0052] For example, the thickness of the light emission adjustment layer 230 of the R sub-pixel can be 750–800 Å, the thickness of the light emission adjustment layer 230 of the G sub-pixel can be 300–350 Å, and the thickness of the light emission adjustment layer 230 of the B sub-pixel can be 50–100 Å.

[0053] In addition, such as Figure 2 As shown in this exemplary embodiment, the microcavity length of the R sub-pixel in the first display area 100 can be greater than the microcavity length of the R sub-pixel in the second display area 200, the microcavity length of the G sub-pixel in the first display area 100 can be the same as the microcavity length of the B sub-pixel in the second display area 200, and the microcavity length of the B sub-pixel in the first display area 100 can be greater than the microcavity length of the B sub-pixel in the second display area 200. For example, the microcavity length of the R sub-pixel in the first display area 100 can be greater than or equal to 2700nm and less than or equal to 2900nm (e.g., 2700nm, 2800nm, 2900nm, etc.), the microcavity length of the G sub-pixel can be greater than or equal to 2150nm and less than or equal to 2350nm (e.g., 2150nm, 2250nm, 2350nm, etc.), and the microcavity length of the B sub-pixel can be greater than or equal to 1900nm and less than or equal to 2100nm (e.g., 1900nm, 2000nm, 2100nm, etc.).

[0054] like Figure 2 As shown in this exemplary embodiment, the thickness of the organic electroluminescent layer (EML) of each sub-pixel in the first display area 100 can be the same or different. When the thickness of the EML of each sub-pixel is the same, the fabrication process can be simplified and the fabrication efficiency improved. For example, the thickness of the EML of each sub-pixel can be 350–400 Å, in which case the organic electroluminescent layer can be deposited on the corresponding sub-pixel without the need for an FMM mask process. When the thickness of the EML of each sub-pixel is different, an FMM mask process can be used to form organic electroluminescent layers of different thicknesses for each sub-pixel. For example, the thickness of the EML of the R sub-pixel can be 450–500 Å, the thickness of the EML of the G sub-pixel can be 350–400 Å, and the thickness of the EML of the B sub-pixel can be 150–200 Å.

[0055] like Figure 2 As shown in this exemplary embodiment, in the first display area 100, the thickness of the organic electroluminescent layer (EML) can have a certain proportional relationship with the thickness of the light-emitting adjustment layer 230. For example, the thickness of the EML of each sub-pixel in the first display area 100 is the same and is d1, and the thickness of the light-emitting adjustment layer 230 of the B sub-pixel in the first display area 100 is d2. d1 / d2 can be greater than or equal to 3 and less than or equal to 9. For example, d / d2 can be 3, 0.35, 4, 0.45, 5, 0.55, 6, 0.65, 7, 0.75, 8, 0.85, 9, etc. For instance, the thickness of the EML of the B sub-pixel in the first display area 100 can be 150–200 Å, and the thickness of the EML of the organic electroluminescent layer in the first display area 100 can be 350–400 Å.

[0056] like Figure 3 As shown in this exemplary embodiment, the microcavity lengths of the R, G, and B sub-pixels in the first display area 100 can be greater than or equal to the microcavity lengths of the corresponding sub-pixels in the second display area 200, and the emission peak wavelength of the emission spectrum curve of each sub-pixel can be determined based on the microcavity length of each sub-pixel in the first display area 100. The emission peak wavelength refers to the wavelength corresponding to the point where the luminescence intensity of the material is maximum, that is, the wavelength corresponding to the highest point in the emission spectrum curve. For example, Figure 4 The emission spectrum curve of an R sub-pixel according to one embodiment of the present disclosure. Figure 5 The emission spectrum curve of a G sub-pixel according to one embodiment of the present disclosure. Figures 3-5 The emission spectrum curve of a B sub-pixel according to one embodiment of the present disclosure. Figures 3-5In the figure, the abscissa represents the wavelength of light, the ordinate represents the luminous intensity, the curve k1 represents the luminous spectrum curve of the R sub-pixel before filtering, k2 represents the absorption spectrum curve of red light, k3 represents the spectrum curve of the light emitted by the R sub-pixel, the curve k4 represents the luminous spectrum curve of the G sub-pixel before filtering, k5 represents the absorption spectrum curve of green light, k6 represents the spectrum curve of the light emitted by the G sub-pixel, the curve k7 represents the luminous spectrum curve of the B sub-pixel before filtering, k8 represents the absorption spectrum curve of blue light, and k9 represents the spectrum curve of the light emitted by the B sub-pixel. Figure 6 It can be seen that the luminous peak wavelength of the luminous spectrum curve of the R sub-pixel is located at 585-605 nm, the luminous peak wavelength of the luminous spectrum curve of the G sub-pixel is 530 nm, and the luminous peak wavelength of the luminous spectrum curve of the B sub-pixel is located at 505-525 nm. The luminous peak wavelength of the luminous spectrum of the R sub-pixel is longer than that of the luminous spectrum of the G sub-pixel, thereby causing the spectral red shift of the light emitted by the organic electroluminescent layer EML in the R sub-pixel, and then the red light is emitted by the R sub-pixel through the filtering effect of the color film layer. Similarly, the luminous peak wavelength of the luminous spectrum of the B sub-pixel is smaller than that of the luminous spectrum of the G sub-pixel, thereby causing the spectral blue shift of the organic electroluminescent layer EML in the B sub-pixel, and then the blue light is emitted by the B sub-pixel through the filtering effect of the color film layer.

[0057] In addition, in the present exemplary embodiment, the y coordinate value of the CIE color coordinates of the B sub-pixel in the first display area 100 can be reduced to further reduce the difference in image quality between the first display area 100 and the second display area 200. For example, the y coordinate value of the CIE color coordinates of the B sub-pixel in the first display area 100 can be reduced to less than or equal to 0.075, such as 0.075, 0.070, 0.065, 0.060, 0.055, 0.050, etc. by adjusting the color film layer.

[0058] In the present exemplary embodiment, in the first display area 100, the organic electroluminescent layer EML of each sub-pixel is formed by the first light-emitting material which emits green light. Since the first light-emitting material has high luminous efficiency, the luminous efficiency of the R sub-pixel and the B sub-pixel in the first display area 100 is improved. Table 1 shows the efficiency comparison of each sub-pixel according to an embodiment of the present disclosure. In table 1, the related art shows that the luminous color of the organic electroluminescent layer of the R, G and B sub-pixels is different, the organic electroluminescent layer of the R sub-pixel is formed by the second light-emitting material, the organic electroluminescent layer of the G sub-pixel is formed by the first light-emitting material, and the organic electroluminescent layer of the B sub-pixel is formed by the third light-emitting material.

[0059] Table 1

[0060]

[0061] As can be seen from Table 1, compared with the comparative example in the related art, the organic electroluminescent layers of the R, G and B sub-pixels in the present exemplary embodiment are all formed by the first luminescent material, which is equivalent to replacing the luminescent materials of the organic electroluminescent layers of the R and B sub-pixels with the first luminescent material with the highest luminous efficiency, so that the lifespan and efficiency of the R and B sub-pixels are both improved, and obviously the comprehensive luminous efficiency and lifespan of the pixel unit composed of the R, G and B sub-pixels are both improved.

[0062] For example, when the first display area 100 is low PPI (Pixels Per Inch, resolution), the light transmittance is no longer the main problem affecting the first display area 100, and because the lifespan of the pixel unit is improved, the first display area 100 has no quality problem, so the anode aperture ratio of the sub-pixel can be reduced to further improve the light transmittance. According to the simulation results of the present disclosure, when the first display area 100 is low PPI, the comprehensive lifespan of the pixel unit can be improved by 220%, and the luminous efficiency can be improved by 3%.

[0063] When the first display area 100 is high PPI, as shown in Table 2, in the related art listed in Table 2, the organic electroluminescent layer of the R sub-pixel is formed by the second luminescent material, the organic electroluminescent layer of the G sub-pixel is formed by the first luminescent material, and the organic electroluminescent layer of the B sub-pixel is formed by the third luminescent material. PDL GAP represents the interval distance between adjacent sub-pixels, and the larger the PDL GAP, the smaller the pixel aperture ratio and the higher the light transmittance. Compared with the lifespan of the pixel unit in the related art, the lifespan of the first display area 100 in the present exemplary embodiment is obviously improved, and the difference between the lifespan of the first display area 100 and the lifespan of the second display area 200 is obviously reduced, so that the small difference in lifespan between the first display area 100 and the second display area 200 can be adjusted by the lifespan compensation algorithm, and finally the lifespan of the first display area 100 can be the same as the lifespan of the second display area 200, solving the display problem in the related art that the quality of the first display area 100 and the second display area 200 is greatly different due to the low lifespan of the first display area 100.

[0064] Table 2

[0065]

[0066] It can be known that the service life of the B sub-pixel is the shortest in a pixel unit, and therefore, it is generally required to ensure that the aperture ratio of the B sub-pixel is the largest, the aperture ratio of the G sub-pixel is the second, and the aperture ratio of the R sub-pixel is the smallest, so as to balance the service life of the three sub-pixels. As shown in Table 1, because the service life and efficiency of the R sub-pixel and the B sub-pixel are both improved, the short service life of the B sub-pixel is no longer the main factor affecting the service life and light transmittance of the first display area 100, and the aperture ratio of the B sub-pixel in the first display area 100 can be reduced to correspondingly improve the light transmittance of the first display area 100, so that the first display area 100 can balance the light transmittance and the service life.

[0067] For example, the aperture ratio of the R sub-pixel in the first display area 100 is k1, the aperture ratio of the G sub-pixel is k2, and the aperture ratio of the B sub-pixel is k3, k1 / k2 can be greater than or equal to 1 / 2 and less than or equal to 1, and k1 / k3 can be greater than or equal to 1 / 4 and less than or equal to 3 / 4, for example, k1 / k2 can be 1 / 2, 3 / 4, 1, k1 / k3 can be 1 / 4, 3 / 8, 1 / 2, 3 / 4, and the like.

[0068] It can be seen that in the case of forming the organic electroluminescent layer EML of the first display area 100 by using the first light-emitting material with high light-emitting efficiency, the service life and efficiency of the R sub-pixel and the B sub-pixel in the first display area 100 can be improved, so that the aperture ratio of the B sub-pixel can be reduced and / or the aperture ratio of the R sub-pixel and the G sub-pixel can be appropriately increased under the premise of ensuring the light transmittance of the first display area 100, so that the light transmittance of the first display area 100 is improved while the service life of the first display area 100 is ensured.

[0069] In summary, the display panel provided by the present disclosure can improve the service life and light transmittance of the FDC area, and the service life compensation algorithm can ensure that the service life of the FDC area is the same as or close to that of the normal display area, thereby solving the display defect problem of the FDC area.

[0070] The present disclosure also provides a preparation method of a display panel, which is used for preparing the display panel described in any of the above embodiments, and can include the following steps:

[0071] S110, providing a substrate 10, wherein the substrate 10 has a first display area 100 and a second display area 200, the first display area 100 is used for image display and light transmission, the second display area 200 is used for image display, and the second display area 200 at least partially surrounds the first display area 100, and the first display area 100 and the second display area 200 both include a plurality of sub-pixels emitting light of different colors;

[0072] S120, forming a light-emitting functional layer 20 on one side of the substrate 10 by using an evaporation process, wherein the light-emitting functional layer 20 comprises an organic electroluminescent layer EML, and the light-emitting functional layer EML of each sub-pixel in the first display area 100 emits light of the same color.

[0073] As described in the above embodiment, the first display area 100 can be an FDC area, and the second display area can be a normal display area. The plurality of sub-pixels can comprise, for example, an R sub-pixel emitting red light, a G sub-pixel emitting green light, and a B sub-pixel emitting blue light.

[0074] In step S110, a first electrode layer and a pixel definition layer PDL can be formed on the first display area 100 and the second display area 200 of the substrate 10, and the pixel definition layer PDL can be patterned by using a patterning process to form a pixel defining structure, and adjacent pixel defining structures define a sub-pixel. For example, the first electrode layer 30 can comprise a plurality of first electrodes spaced apart from each other, and the orthographic projection of each first electrode on the substrate is located in the pixel area. The first electrode can be an anode. An organic photoresist material can be coated on the substrate 10 on which the anode layer is formed. The coating method can comprise slot coating, spin coating, etc. The thickness of the organic photoresist material is higher than the height of the anode layer. The organic photoresist material can be subjected to half-etching or ion etching to remove the organic material layer on the surface of the anode layer, thereby forming the pixel definition layer PDL. The patterning process can comprise an exposure developer process. By using the patterning process, a plurality of pixel defining structures 310 can be formed, and the plurality of pixel defining structures 310 are spaced apart from each other in the extension direction of the pixel definition layer PDL, and adjacent two pixel defining structures define a sub-pixel.

[0075] Step S120 is to form the organic electroluminescent layer EML by using an evaporation process. By evaporating the same light-emitting material in the first display area 100 to form the organic electroluminescent layer EML of each sub-pixel, the first display area 100 can have the same turn-on voltage of each sub-pixel, solve the problem of white picture color pieces at low gray scale, and improve the display quality of the first display area 100.

[0076] Further, the organic electroluminescent layer EML of each sub-pixel in the first display area 100 can be formed by using the first light-emitting material with the highest light-emitting efficiency, i.e., the organic electroluminescent layer EML of the first display area 100 emits green light, thereby improving the service life and light transmittance of each sub-pixel in the first display area 100. The evaporation process of step S120 will be further described below by taking the example of evaporating the first light-emitting material emitting green light in the first display area 100. Step S120 can specifically comprise the following steps:

[0077] S121, evaporate a first organic material on the pixel definition layer PDL and the first electrode layer to form a first organic layer 210. The first organic layer 210 can include a hole injection layer HIL and a hole transport layer HTL. The sub-pixel structure of a pixel unit of the first display area 100 and the second display area 200 obtained is as shown in Figure 7 .

[0078] S122, evaporate to form array-distributed R light-emitting adjustment layers 230, G light-emitting adjustment layers 230 and B light-emitting adjustment layers 230 on the first organic layer 210. The thicknesses of the R light-emitting adjustment layers 230, the G light-emitting adjustment layers 230 and the B light-emitting adjustment layers 230 are different from each other, the thickness of the light-emitting adjustment layer 230 of the B sub-pixel is the smallest, and the thickness of the light-emitting adjustment layer 230 of the R sub-pixel is the largest. A fine mask FMM can be used to evaporate to form light-emitting adjustment layers 230 with different thicknesses on the first organic layer 210. The pixel unit structure obtained is as shown in Figure 8 .

[0079] S123, evaporate a second light-emitting material on the R light-emitting adjustment layer 230 of the second display area 200, evaporate a first light-emitting material on the G light-emitting adjustment layer 230, and evaporate a third light-emitting material on the B light-emitting adjustment layer 230 to form an organic electroluminescent layer EML of the second display area 200, and evaporate the first light-emitting material on the R, G and B light-emitting adjustment layers of the first display area 100 to form an organic electroluminescent layer EML of the first display area 100.

[0080] In this step, a fine mask can be used to evaporate a second light-emitting material on the R sub-pixel of the second display area 200, evaporate a first light-emitting material on the G sub-pixel of the second display area 200 and the first display area 100, and evaporate a third light-emitting material on the B sub-pixel of the second display area 200, in other words, the first display area 100 does not evaporate the second light-emitting material and the third light-emitting material, but only evaporates the first light-emitting material, so that the organic electroluminescent layer EML of the R, G and B sub-pixels of the first display area 100 emits light of the same color and has the highest light-emitting efficiency, thereby improving the service life of the R sub-pixel and the B sub-pixel. The pixel unit structure obtained is as shown in Figure 9 .

[0081] S124, evaporate a second organic material on the organic electroluminescent layer EML to form a second organic layer 220. The second organic layer 220 can include an electron transport layer ETL and an electron injection layer EIL. In some embodiments, a hole blocking layer HBL can also be evaporated on the organic electroluminescent layer EML, and then the second organic layer 220 is formed by evaporating on the hole blocking layer HBL. The pixel unit structure obtained is as shown in Figure 10 .

[0082] After the light-emitting functional layer 20 is formed by evaporation, a second electrode layer 220 can be further formed on the light-emitting functional layer by evaporation, obtaining a pixel unit structure as shown in FIG. 2B. ​

[0083] Further, a color filter layer can be formed on the second electrode layer 220 by encapsulation process, the color filter layer including a filter part corresponding to each sub-pixel, the filter part being used for transmitting light of a corresponding color. In addition, the present disclosure also provides a display device, which can include the display panel described in any of the above embodiments, and thus the display device also has the beneficial effects described in any of the above embodiments.

[0084] In addition, the present disclosure also provides a display device, which includes the display panel described in any of the above embodiments, and thus the display device also has the beneficial effects described in any of the above embodiments.

[0085] Other embodiments of the present disclosure will be apparent to those skilled in the art upon consideration of the specification and practice of the present disclosure. The present application is intended to cover any variations, uses or adaptive changes of the present disclosure following the general principles thereof and including general knowledge or custom in the art not disclosed in the present disclosure. The specification and examples are only considered as exemplary, and the true scope and spirit of the present disclosure are indicated by the claims.​

Claims

1. A display panel, characterized in that, include: A substrate, the substrate including a first display area and a second display area at least partially surrounding the first display area, the first display area being used for image display and light transmission, and the second display area being used for image display; A light-emitting functional layer is located on one side of the substrate, and the light-emitting functional layer includes an organic electroluminescent layer; The first display area and the second display area each include multiple sub-pixels that emit light of different colors. The organic electroluminescent layer of each sub-pixel in the first display area emits light of the same color, so that each sub-pixel has the same turn-on voltage, thus avoiding color cast in low grayscale white images. The multiple sub-pixels in the first display area include an R sub-pixel that emits red light, a G sub-pixel that emits green light, and a B sub-pixel that emits blue light; The organic electroluminescent layer of each sub-pixel located in the first display area emits green light; The light-emitting functional layer also includes: A first organic layer is located between the organic electroluminescent layer and the substrate; A light-emitting modulation layer is located between the organic electroluminescent layer and the first organic layer; The second organic layer is located on the side of the organic electroluminescent layer opposite to the substrate and covers the organic electroluminescent layer; The display panel also includes: The first electrode layer is located between the substrate and the first organic layer; The second electrode layer is located on the side of the second organic layer that is away from the substrate and covers the second organic layer; The first electrode layer, the first organic layer, the light-emitting adjustment layer, the organic electroluminescent layer, the second organic layer, and the second electrode layer, which are stacked together, constitute the microcavity of the sub-pixel. In the first display area, the microcavity length of the R sub-pixel, the microcavity length of the G sub-pixel, and the microcavity length of the B sub-pixel decrease sequentially.

2. The display panel according to claim 1, characterized in that, The plurality of sub-pixels in the first display area include at least a first sub-pixel and a second sub-pixel, wherein the color of the light emitted from the first sub-pixel is different from the color of the light emitted from the second sub-pixel; Both the organic electroluminescent layer of the first sub-pixel and the organic electroluminescent layer of the second sub-pixel are formed of a first luminescent material. The luminescent color of the first luminescent material is the same as the color of the light emitted from the first sub-pixel, and the luminescent efficiency of the first luminescent material is greater than that of the second luminescent material. The luminescent color of the second luminescent material is the same as the color of the light emitted from the second sub-pixel.

3. The display panel according to claim 1, characterized in that, In the first display area, the thickness of the organic electroluminescent layer of the R sub-pixel, the thickness of the organic electroluminescent layer of the G sub-pixel, and the thickness of the organic electroluminescent layer of the B sub-pixel decrease sequentially.

4. The display panel according to claim 1, characterized in that, The organic electroluminescent layer of each sub-pixel in the first display area has the same thickness.

5. The display panel according to claim 4, characterized in that, The light-emitting functional layer also includes: A first organic layer is located between the organic electroluminescent layer and the substrate; A light-emitting modulation layer is located between the organic electroluminescent layer and the first organic layer; In the first display area, the thickness of the organic electroluminescent layer of each sub-pixel is d1, the thickness of the light-emitting adjustment layer of the B sub-pixel is d2, and d1 / d2 is greater than or equal to 3 and less than or equal to 9.

6. The display panel according to claim 1, characterized in that, The pixel resolution of the first display area is the same as that of the second display area.

7. The display panel according to claim 6, characterized in that, In the first display area, the aperture ratio of the R sub-pixel is k1, the aperture ratio of the G sub-pixel is k2, and the aperture ratio of the B sub-pixel is k3. k1 / k2 is greater than or equal to 1 / 2 and less than or equal to 1, and k1 / k3 is greater than or equal to 1 / 4 and less than or equal to 3 / 4.

8. The display panel according to claim 1, characterized in that, The microcavity length of the R sub-pixel in the first display area is greater than the microcavity length of the R sub-pixel in the second display area. The microcavity length of the G sub-pixel in the first display area is the same as the microcavity length of the B sub-pixel in the second display area. The microcavity length of the B sub-pixel in the first display area is greater than the microcavity length of the B sub-pixel in the second display area.

9. The display panel according to claim 8, characterized in that, In the first display area, the microcavity length of the R sub-pixel is greater than or equal to 2700nm and less than or equal to 2900nm, and the microcavity length of the B sub-pixel is greater than or equal to 1900nm and less than or equal to 2100nm.

10. The display panel according to claim 1, characterized in that, In the first display area, the emission peak wavelength of the emission spectrum curve of the R sub-pixel is located in the range of 585 to 605 nm, and the emission peak wavelength of the emission spectrum curve of the B sub-pixel is located in the range of 505 to 525 nm.

11. The display panel according to claim 1, characterized in that, In the first display area, the y-coordinate value of the CIE color coordinate of the B sub-pixel is less than or equal to 0.

075.

12. A method for manufacturing a display panel, used to manufacture the display panel according to any one of claims 1-11, characterized in that, The method includes: A substrate is provided, wherein the substrate has a first display area and a second display area, the first display area is used for displaying images and transmitting light, the second display area is used for displaying images, and the second display area at least partially surrounds the first display area, and both the first display area and the second display area include a plurality of sub-pixels that emit light of different colors; A light-emitting functional layer is formed on one side of the substrate using a vapor deposition process. The light-emitting functional layer includes an organic electroluminescent layer, and the light emitted from the organic electroluminescent layer of each sub-pixel in the first display area is of the same color.

13. The method according to claim 12, characterized in that, The method of forming a light-emitting functional layer on one side of the substrate using a vapor deposition process includes: A first organic layer is deposited on the first display area and the second display area of ​​the substrate by vapor deposition; An array of R-light-regulating layers, G-light-regulating layers, and B-light-regulating layers are vapor-deposited on the first organic layer; An organic electroluminescent layer for the second display area is formed by depositing a second luminescent material on the R luminescent adjustment layer, a first luminescent material on the G luminescent adjustment layer, and a third luminescent material on the B luminescent adjustment layer. An organic electroluminescent layer for the first display area is formed by depositing the first luminescent material on the R luminescent adjustment layer, the G luminescent adjustment layer, and the B luminescent adjustment layer. The luminous efficiency of the first luminescent material is greater than that of the second luminescent material and the third luminescent material. A second organic layer is formed by vapor deposition on the organic electroluminescent layer.

14. The method according to claim 12, characterized in that, Before forming the light-emitting functional layer on one side of the substrate using a vapor deposition process, the method further includes: A first electrode layer and a pixel definition layer are formed in the first display area and the second display area on the substrate; The pixel definition layer is patterned using a patterning technique to form a pixel boundary structure, wherein adjacent pixel boundary structures define the sub-pixels.

15. The method according to claim 12, characterized in that, After forming a light-emitting functional layer on one side of the substrate using a vapor deposition process, the method further includes: A second electrode layer is formed by vapor deposition on the light-emitting functional layer; A color filter layer is formed on the second electrode layer using an encapsulation process. The color filter layer includes a filter portion corresponding to each of the sub-pixels, and the filter portion is used to transmit light of the corresponding color.

16. A display device, characterized in that, Includes the display panel as described in any one of claims 1-11.

Images