Display panel and display device

Abstract

The invention discloses a display panel and a display device, and belongs to the technical field of display. The pixel definition layer is arranged on the substrate and defines a plurality of pixel openings; the multiple light-emitting units are arranged in the multiple pixel openings respectively, each light-emitting unit comprises a hole function layer and a light-emitting layer, and the light-emitting layer is arranged on the side, away from the substrate, of the hole function layer; wherein the plurality of light-emitting units comprise a first light-emitting unit, on the cross section of the first light-emitting unit, the orthographic projection length of the hole function layer on the substrate and the orthographic projection length of the light-emitting layer on the substrate have a first difference value, and the first difference value is greater than 0. The orthographic projection length of the light-emitting layer on the substrate is smaller than the orthographic projection length of the hole function layer on the substrate on the cross section of the first light-emitting unit, so that the problem of alignment deviation between the hole function layer and the light-emitting layer in the first light-emitting unit can be avoided, and the display effect of the display panel can be improved.

Description

Technical Field

[0001] This application relates to the field of display technology, and more particularly to a display panel and display device. Background Technology

[0002] Organic light-emitting diode (OLED) display technology has been widely used in smartphones, televisions, wearable devices, and flexible displays. OLED display panels consist of light-emitting units.

[0003] In related technologies, there is a problem of alignment deviation between the light-emitting unit layer structure, which affects the display effect of the display panel. Summary of the Invention

[0004] This application provides a display panel and a display device to at least partially solve the above-mentioned technical problems.

[0005] To achieve the above objectives, according to a first aspect of this application, a display panel is provided, comprising: substrate; A pixel definition layer is provided on the substrate and defines multiple pixel openings; Multiple light-emitting units are respectively disposed in multiple pixel openings. Each light-emitting unit includes a hole functional layer and a light-emitting layer. The light-emitting layer is disposed on the side of the hole functional layer away from the substrate. Among them, the multiple light-emitting units include a first light-emitting unit. On the cross-section of the first light-emitting unit, the orthographic projection length of the hole functional layer on the substrate and the orthographic projection length of the light-emitting layer on the substrate have a first difference, which is greater than 0.

[0006] Optionally, the hole functional layer includes a hole injection layer and a hole transport layer. The hole transport layer is disposed between the hole injection layer and the light-emitting layer. On the cross-section of the first light-emitting unit, the orthographic projection length of the hole injection layer on the substrate and the orthographic projection length of the hole transport layer on the substrate have a second difference, wherein the first difference is greater than the absolute value of the second difference.

[0007] Optionally, the light-emitting unit further includes an electronic functional layer, which is disposed on the side of the light-emitting layer away from the substrate; on the cross section of the first light-emitting unit, the orthographic projection length of the electronic functional layer on the substrate and the orthographic projection length of the light-emitting layer on the substrate have a third difference, wherein the third difference is greater than 0 and the first difference is less than the third difference.

[0008] Optionally, the plurality of light-emitting units further includes a second light-emitting unit, wherein on the cross section of the second light-emitting unit, the orthogonal projection length of the light-emitting layer on the substrate and the orthogonal projection length of the hole functional layer on the substrate have a fourth difference; wherein the fourth difference is greater than 0, and the first difference is greater than the fourth difference.

[0009] Optionally, the peak value of the emission peak of the first light-emitting unit is smaller than the peak value of the emission peak of the second light-emitting unit.

[0010] Optionally, the light-emitting unit further includes an electronic functional layer, which is disposed on the side of the light-emitting layer away from the substrate; the hole functional layer includes a hole injection layer and a hole transport layer, which is disposed between the hole injection layer and the light-emitting layer; wherein, in the first light-emitting unit, the shortest distance between the hole injection layer and the electronic functional layer is not less than 40 nm.

[0011] Optionally, the plurality of pixel openings include a first pixel opening, and a first light-emitting unit is disposed in the first pixel opening. The sidewall of the first pixel opening is recessed to form a buffer space, and the hole injection layer includes a filling portion disposed in the buffer space; or, a step is formed on the sidewall of the first pixel opening, the step includes a step surface facing away from the substrate, and the hole injection layer covers the step surface.

[0012] Optionally, in the first light-emitting unit, the thickness at the center of the hole transport layer is greater than the thickness at the center of the hole injection layer, and the difference between the thickness at the center of the hole transport layer and the thickness at the center of the hole injection layer is not less than 10 nm.

[0013] Optionally, the aperture of the first pixel opening tends to increase in the direction from the substrate to the pixel definition layer.

[0014] Optionally, the plurality of pixel openings includes a first pixel opening, wherein the diameter of the first pixel opening decreases in the direction from the substrate to the pixel defining layer.

[0015] According to a second aspect of this application, a display device is provided, comprising a display panel including any one of the above.

[0016] The display panel of this application embodiment avoids the problem of alignment deviation between the hole functional layer and the light-emitting layer in the first light-emitting unit by making the orthogonal projection length of the light-emitting layer on the substrate on the cross section of the first light-emitting unit smaller than the orthogonal projection length of the hole functional layer on the substrate, thereby improving the display effect of the display panel.

[0017] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description 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 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.

[0018] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0019] Figure 1 This is a cross-sectional view of a display panel provided in an exemplary embodiment of this disclosure; Figure 2 This is a schematic diagram of the structure of the first region and the second region on the substrate provided in the exemplary embodiments of this disclosure; Figure 3 yes Figure 1 A cross-sectional view of the first light-emitting unit in the display panel shown, located at the opening of the first pixel; Figure 4 This is a cross-sectional view of another first light-emitting unit provided in an exemplary embodiment of this disclosure, disposed at the opening of the first pixel; Figure 5 yes Figure 1 The second light-emitting unit in the display panel shown is located at the second pixel opening in a cross-sectional view. Figure 6 yes Figure 1 The third light-emitting unit in the display panel shown is located at the opening of the third pixel in a cross-sectional view. Figure 7 This is a cross-sectional view of another display panel provided in an exemplary embodiment of this disclosure; Figure 8 yes Figure 7 The first light-emitting unit in the display panel shown is located behind the opening of the first pixel; Figure 9 yes Figure 8 An enlarged view of part a; Figure 10 yes Figure 8 A top-down view of the buffer space distribution of the mid-pixel definition layer; Figure 11 This is a cross-sectional view of another first light-emitting unit provided in an exemplary embodiment of this disclosure, disposed behind another first pixel opening; Figure 12 yes Figure 11 Enlarged view of section b; Figure 13 yes Figure 11 Distribution diagram of the buffer space after looking up from the mid-pixel definition layer; Figure 14 This is a cross-sectional view of a first light-emitting unit disposed behind a first pixel opening, provided in an exemplary embodiment of this disclosure; Figure 15 This is a cross-sectional view of the first light-emitting unit provided in the exemplary embodiment of this disclosure, located behind the opening of the first pixel. Figure 16 This is a cross-sectional view of the first light-emitting unit provided in an exemplary embodiment of this disclosure, located behind the opening of the first pixel.

[0020] Explanation of reference numerals in the attached figures: 1. Substrate; 2. Pixel definition layer; 21. Pixel opening; 21A. First pixel opening; 23. Buffer space; 25. Step; 251. Step surface; 21B. Second pixel opening; 21C. Third pixel opening; 3. Light-emitting unit; 3A. First light-emitting unit; 3B. Second light-emitting unit; 3C. Third light-emitting unit; 31. Hole functional layer; 31A. Second region; 311. Hole injection layer; 3111. Filling portion; 313. Hole transport layer; 33. Light-emitting layer; 33A. First region; 35. Electron functional layer; 351. Electron transport layer; 4. Anode; D. Shortest distance; X, first direction; Y, the second direction; Z, direction of ascent; O, axis of symmetry. Detailed Implementation

[0021] 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 them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0022] Organic light-emitting diode (OLED) display technology has been widely used in smartphones, televisions, wearable devices, and flexible displays. OLED display panels consist of light-emitting units.

[0023] In related technologies, there is a misalignment problem between the hole functional layer and the light-emitting layer of the light-emitting unit. This misalignment affects the color purity and yield of the light-emitting unit, thereby affecting the display effect of the display panel, especially the display effect of high-resolution display panels.

[0024] To address the aforementioned technical problems, this application provides a display panel and a display device.

[0025] According to the first aspect of this application, referring to Figures 1 to 4 This disclosure provides a display panel, including a substrate 1, a pixel definition layer 2, and a plurality of light-emitting units 3. The pixel definition layer 2 is disposed on the substrate 1 and defines a plurality of pixel openings 21. The plurality of light-emitting units 3 are respectively disposed in the plurality of pixel openings 21. The light-emitting unit 3 includes a hole function layer 31 and a light-emitting layer 33. The light-emitting layer 33 is disposed on the side of the hole function layer 31 away from the substrate 1. The plurality of light-emitting units 3 includes a first light-emitting unit 3A. On the cross-section of the first light-emitting unit 3A, the orthographic projection length L2 of the hole function layer 31 on the substrate 1 and the orthographic projection length L1 of the light-emitting layer 33 on the substrate 1 have a first difference d1, and the first difference d1 is greater than 0. In other words, d1 = L2 - L1, and on the cross section of the first light-emitting unit 3A, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 is greater than the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1; or, on the cross section of the first light-emitting unit 3A, the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 is less than the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1.

[0026] The technical solution disclosed herein avoids the alignment deviation between the hole functional layer 31 and the light-emitting layer 33 in the first light-emitting unit 3A by making the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 smaller than the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 in the cross section of the first light-emitting unit 3A, thereby improving the display effect of the display panel.

[0027] like Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 11 , Figures 14 to 16 As shown, in the embodiments of this disclosure, the display panel further includes an anode 4 and a cathode (not shown). The anode 4 is disposed on the substrate 1 and located at the pixel opening 21, and the cathode (not shown) is disposed on the light-emitting unit 3. The anode 4, the light-emitting unit 3, and the cathode (not shown) constitute the main structure of the organic electroluminescent device, used to provide a light source for the display panel.

[0028] In embodiments of this disclosure, the light-emitting unit 3 can be formed in the pixel opening 21 by a printing process.

[0029] Optionally, the pixel opening 21 can be circular, rectangular, racetrack-shaped, etc., and multiple pixel openings 21 can also be provided with pixel openings 21 having at least two shapes. This disclosure does not make specific limitations in this regard.

[0030] For example, the pixel opening 21 is rectangular in shape.

[0031] like Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 11 , Figures 14 to 16 As shown, in some embodiments, the light-emitting unit 3 further includes an electronic functional layer 35, which is disposed on the side of the light-emitting layer 33 away from the substrate 1; the hole functional layer 31 includes a hole injection layer 311 and a hole transport layer 313, which is disposed between the hole injection layer 311 and the light-emitting layer 33.

[0032] Optionally, the electronic functional layer 35 includes an electron injection layer (not shown) disposed between the light-emitting layer 33 and the cathode (not shown); or, the electronic functional layer 35 includes an electron injection layer (not shown) and an electron transport layer 351, with the electron transport layer 351 disposed on the side of the light-emitting layer 33 away from the substrate 1, and the electron injection layer (not shown) disposed between the electron transport layer 351 and the cathode (not shown). This disclosure does not specifically limit the scope of the application.

[0033] Exemplarily, the electronic functional layer 35 includes an electron injection layer (not shown) and an electron transport layer 351. When energized, the anode 4 generates holes, and the cathode (not shown) generates electrons. Holes are transported to the light-emitting layer 33 via the hole injection layer 311 and the hole transport layer 313, while electrons are transported to the light-emitting layer 33 via the electron injection layer (not shown) and the electron transport layer 351, so that electrons and holes recombine in the light-emitting layer 33 to generate photons. The material of the light-emitting layer 33 determines the color and efficiency of the emitted light.

[0034] like Figures 2 to 4As shown, in the embodiments of this disclosure, the orthographic projection area of ​​the light-emitting layer 33 on the substrate 1 is the first region 33A, and the orthographic projection area of ​​the hole-functional layer 31 on the substrate 1 is the second region 31A. In the first light-emitting unit 3A, the first region 33A is within the range of the second region 31A, and the minimum distance between any point on the outline of the first region 33A and the outline of the second region 31A is equal to the first difference d1. Therefore, on any cross-section of the display panel, there exists a first difference d1 between the orthographic projection length L2 of the hole-functional layer 31 on the substrate 1 and the orthographic projection length L1 of the light-emitting layer 33 on the substrate 1. That is to say, in the first light-emitting unit 3A, the light-emitting layer 33 cannot cover the hole-functional layer 31.

[0035] It should be noted that any cross-section of the display panel is a plane.

[0036] like Figure 2 , Figure 3 and Figure 4 As shown, in the embodiments of this disclosure, in the first light-emitting unit 3A, the dimensions of the second region 31A and the first region 33A in any direction have a first difference d1. That is, in the first light-emitting unit 3A, there is a distance of the first difference d1 between the outline of the first region 33A and the outline of the second region 31A.

[0037] Optionally, in the first light-emitting unit 3A, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 can be the size of the second region 31A in the first direction X, and the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 can be the size of the first region 33A in the first direction X. Therefore, the first difference d1 is the difference between the size of the second region 31A in the first direction X and the size of the first region 33A in the first direction X. In the first light-emitting unit 3A, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 can also be the size of the second region 31A in the second direction Y, and the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 can also be the size of the first region 33A in the second direction Y. Therefore, the first difference d1 can also be the difference between the size of the second region 31A in the second direction Y and the size of the first region 33A in the second direction Y.

[0038] It is understood that the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 is not limited to the size of the second region 31A in the first direction X or the second direction Y, and the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 is not limited to the size of the first region 33A in the first direction X or the second direction Y. That is, the first difference d1 is not limited to the difference between the second region 31A and the first region 33A in the first direction X or the second direction Y. For example, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 can also be the size of the second region 31A in other directions (not shown), and the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 can also be the size of the first region 33A in other directions (not shown). That is, the first difference d1 can also be the difference between the size of the second region 31A in other directions (not shown) and the size of the first region 33A in other directions (not shown). Other directions intersect with the first direction X and the second direction Y.

[0039] For example, in the first light-emitting unit 3A, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 is the dimension of the second region 31A in the first direction X, and the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 is the dimension of the first region 33A in the first direction X; that is, the first difference d1 is the difference between the dimension of the second region 31A in the first direction X and the dimension of the first region 33A in the first direction X. Specifically, in the first light-emitting unit 3A, the dimension of the first region 33A in the first direction X is also L1, and the dimension of the second region 31A in the first direction X is also L2.

[0040] Optionally, the angle between the first direction X and the second direction Y is greater than 0° and less than 180°. Specifically, the angle between the first direction X and the second direction Y can be 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, or 170°, etc. It is understood that the angle between the first direction X and the second direction Y is not limited to the above-mentioned angle values. For example, the angle between the first direction X and the second direction Y can also be between any two of the above values. This disclosure does not specifically limit this.

[0041] like Figure 2 As shown, for example, the angle between the first direction X and the second direction Y is 90°.

[0042] In such Figure 3In the illustrated embodiment, on the cross-section of the first light-emitting unit 3A, the orthogonal projection length of the hole injection layer 311 on the substrate 1 and the orthogonal projection length of the hole transport layer 313 on the substrate 1 have a second difference, and the second difference is not greater than 0. That is, the orthogonal projection length of the hole injection layer 311 on the substrate 1 is not greater than the orthogonal projection length of the hole transport layer 313 on the substrate 1, meaning that the hole transport layer 313 can cover the hole injection layer 311.

[0043] It should be noted that, in cases such as Figure 3 In the illustrated embodiment, in the first light-emitting unit 3A, since the orthogonal projection length of the hole injection layer 311 on the substrate 1 is not greater than the orthogonal projection length of the hole transport layer 313 on the substrate 1, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 is the same as the orthogonal projection length of the hole transport layer 313 on the substrate 1. Here, the absolute value of the second difference is defined as d2, and the orthogonal projection length of the hole injection layer 311 on the substrate 1 is defined as L3. Then, the absolute value of the second difference d2 is equal to L2 - L3, wherein the first difference d1 is greater than the absolute value of the second difference d2.

[0044] It should also be noted that, Figure 8 , Figure 11 , Figure 14 , Figure 15 and Figure 16 In the embodiment shown, on the cross section of the first light-emitting unit 3A, the orthogonal projection length of the hole injection layer 311 on the substrate 1 and the orthogonal projection length of the hole transport layer 313 on the substrate 1 also have a second difference, and the second difference is not greater than 0.

[0045] like Figure 4 In the illustrated embodiment, on the cross-section of the first light-emitting unit 3A, the orthogonal projection length of the hole injection layer 311 on the substrate 1 and the orthogonal projection length of the hole transport layer 313 on the substrate 1 have a second difference d2, and the second difference d2 is greater than 0. That is, the orthogonal projection length of the hole injection layer 311 on the substrate 1 is greater than the orthogonal projection length of the hole transport layer 313 on the substrate 1, meaning that the hole transport layer 313 cannot cover the hole injection layer 311.

[0046] It should be noted that, in cases such as Figure 4 In the illustrated embodiment, in the first light-emitting unit 3A, since the orthogonal projection length of the hole injection layer 311 on the substrate 1 is greater than the orthogonal projection length of the hole transport layer 313 on the substrate 1, the orthogonal projection length L2 of the hole functional layer 31 on the substrate 1 is equal to the orthogonal projection length of the hole injection layer 311 on the substrate 1. Here, the orthogonal projection length of the hole transport layer 313 on the substrate 1 is defined as L4, then the second difference d2 is equal to L2-L4, wherein the first difference d1 is greater than the absolute value of the second difference d2.

[0047] In such Figure 3 and Figure 4 In the embodiment shown, on the cross section of the first light-emitting unit 3A, the orthogonal projection length L5 of the electronic functional layer 35 on the substrate 1 and the orthogonal projection length L1 of the light-emitting layer 33 on the substrate 1 have a third difference d3, that is, d3=L5-L1, wherein the third difference d3 is greater than 0, and the first difference d1 is less than the third difference d3.

[0048] It should be noted that, in the embodiments of this disclosure, the orthographic projection length L5 of the electronic functional layer 35 on the substrate 1 is the orthographic projection length of the electronic transport layer 351 on the substrate 1.

[0049] It should also be noted that, Figure 8 , Figure 11 , Figure 14 , Figure 15 and Figure 16 In the embodiment shown, on the cross section of the first light-emitting unit 3A, the orthogonal projection length of the electronic functional layer 35 on the substrate 1 and the orthogonal projection length of the light-emitting layer 33 on the substrate 1 also have a third difference, wherein the first difference is smaller than the third difference.

[0050] In such Figure 1 , Figure 2 , Figure 5 and Figure 7 In the illustrated embodiment, the plurality of light-emitting units 3 further includes a second light-emitting unit 3B. On the cross-section of the second light-emitting unit 3B, the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 and the orthogonal projection length L7 of the hole-functional layer 31 on the substrate 1 have a fourth difference d4, i.e., d4 = L6 - L7. Wherein, the fourth difference d4 is greater than 0, and the first difference d1 is greater than the fourth difference d4, i.e., L2 - L1 > L6 - L7. By making the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 greater than the orthogonal projection length L7 of the hole-functional layer 31 on the substrate 1 on the cross-section of the second light-emitting unit 3B, the alignment misalignment problem between the hole-functional layer 31 and the light-emitting layer 33 in the second light-emitting unit 3B can be avoided, thereby improving the display effect of the display panel.

[0051] It should be noted that the cross-section of the second light-emitting unit 3B is coplanar with the cross-section of the first light-emitting unit 3A described above; in such cases... Figure 5 In the embodiment shown, in the second light-emitting unit 3B, the orthogonal projection length of the hole injection layer 311 on the substrate 1 is less than the orthogonal projection length of the hole transport layer 313 on the substrate 1. Therefore, the orthogonal projection length L7 of the hole functional layer 31 on the substrate 1 is the orthogonal projection length of the hole transport layer 313 on the substrate 1.

[0052] In the embodiments of this disclosure, in the second light-emitting unit 3B, the second region 31A is located within the first region 33A, and the minimum distance between any point on the outline of the first region 33A and the outline of the second region 31A is equal to the fourth difference d4. Therefore, on any cross-section of the display panel, the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 and the orthogonal projection length L7 of the hole functional layer 31 on the substrate 1 have the fourth difference d4. That is, in the second light-emitting unit 3B, the light-emitting layer 33 can cover the hole functional layer 31.

[0053] In some embodiments, in the second light-emitting unit 3B, the dimensions of the first region 33A and the second region 31A in any direction have a fourth difference d4. That is, in the second light-emitting unit 3B, there is a spacing of the fourth difference d4 between the outline of the first region 33A and the outline of the second region 31A.

[0054] Optionally, in the second light-emitting unit 3B, the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 can be the dimension of the first region 33A in the first direction X, and the orthogonal projection length L7 of the hole functional layer 31 on the substrate 1 can be the dimension of the second region 31A in the first direction X. That is, the fourth difference d4 is the difference between the dimension of the second region 31A in the first direction X and the dimension of the first region 33A in the first direction X. In the second light-emitting unit 3B, the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 can be the dimension of the first region 33A in the second direction Y, and the orthogonal projection length L7 of the hole functional layer 31 on the substrate 1 can be the dimension of the second region 31A in the second direction Y. That is, the fourth difference d4 is the difference between the dimension of the second region 31A in the second direction Y and the dimension of the first region 33A in the second direction Y. It is understood that the fourth difference d4 of this disclosure is not limited to the difference between the first region 33A and the second region 31A in the first direction X or the second direction Y. For example, the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 can be the size of the first region 33A in other directions (not shown), and the orthogonal projection length L7 of the hole functional layer 31 on the substrate 1 can be the size of the second region 31A in other directions (not shown). That is, the fourth difference d4 can also be the difference between the size of the second region 31A in other directions (not shown) and the size of the first region 33A in other directions (not shown), where other directions intersect with the first direction X and the second direction Y.

[0055] like Figure 2 and Figure 5As shown, exemplarily, in the second light-emitting unit 3B, the orthogonal projection length L6 of the light-emitting layer 33 on the substrate 1 is the dimension of the first region 33A in the first direction X, and the orthogonal projection length L7 of the hole functional layer 31 on the substrate 1 is the dimension of the second region 31A in the first direction X. That is, the fourth difference d4 is the difference between the dimension of the second region 31A in the first direction X and the dimension of the first region 33A in the first direction X. Specifically, in the second light-emitting unit 3B, the dimension of the first region 33A in the first direction X is also L6, and the dimension of the second region 31A in the first direction X is also L7.

[0056] In some embodiments, the peak value of the emission peak of the first light-emitting unit 3A is smaller than the peak value of the emission peak of the second light-emitting unit 3B.

[0057] It should be noted that the emission peak refers to the emission spectrum of the light-emitting unit 3, which is a curve in which the intensity changes with the wavelength. One or more bulges on this curve are the emission peaks. The peak value of the emission peak corresponds to the center wavelength of the emission spectrum of the light-emitting unit 3, and this center wavelength determines the emission color of the light-emitting unit 3.

[0058] Optionally, the first light-emitting unit 3A is a blue light-emitting unit; the second light-emitting unit 3B can be a red light-emitting unit or a green light-emitting unit.

[0059] like Figure 1 , Figure 2 , Figure 6 and Figure 7 As shown, in some embodiments, the plurality of light-emitting units 3 further includes a third light-emitting unit 3C. On the cross-section of the third light-emitting unit 3C, the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 and the orthogonal projection length L9 of the hole-functional layer 31 on the substrate 1 have a fifth difference d5, i.e., d5 = L8 - L9; wherein, the fifth difference d5 is greater than 0, and the first difference d1 is greater than the fifth difference d5, i.e., L2 - L1 > L8 - L9. By making the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 greater than the orthogonal projection length L9 of the hole-functional layer 31 on the substrate 1 on the cross-section of the third light-emitting unit 3C, the problem of alignment deviation between the hole-functional layer 31 and the light-emitting layer 33 in the third light-emitting unit 3C can be avoided, thereby improving the display effect of the display panel.

[0060] It should be noted that the cross-section of the third light-emitting unit 3C is coplanar with the cross-sections of the first light-emitting unit 3A and the second light-emitting unit 3B described above; in such cases... Figure 6In the embodiment shown, in the third light-emitting unit 3C, the orthogonal projection length of the hole injection layer 311 on the substrate 1 is less than the orthogonal projection length of the hole transport layer 313 on the substrate 1. Therefore, the orthogonal projection length L9 of the hole functional layer 31 on the substrate 1 is the orthogonal projection length of the hole transport layer 313 on the substrate 1.

[0061] In the embodiments of this disclosure, in the third light-emitting unit 3C, the second region 31A is located within the first region 33A, and the minimum distance between any point on the outline of the first region 33A and the outline of the second region 31A is equal to the fifth difference d5. Therefore, on any cross-section of the display panel, the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 and the orthogonal projection length L9 of the hole functional layer 31 on the substrate 1 have the fifth difference d5. That is, in the third light-emitting unit 3C, the light-emitting layer 33 can cover the hole functional layer 31.

[0062] In some embodiments, in the third light-emitting unit 3C, the dimensions of the first region 33A and the second region 31A in any direction have a fifth difference d5. That is, in the third light-emitting unit 3C, there is a spacing of the fifth difference d5 between the outline of the first region 33A and the outline of the second region 31A.

[0063] Optionally, in the third light-emitting unit 3C, the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 can be the dimension of the first region 33A in the first direction X, and the orthogonal projection length L9 of the hole functional layer 31 on the substrate 1 can be the dimension of the second region 31A in the first direction X. That is, the fifth difference d5 is the difference between the dimension of the second region 31A in the first direction X and the dimension of the first region 33A in the first direction X. In the third light-emitting unit 3C, the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 can be the dimension of the first region 33A in the second direction Y, and the orthogonal projection length L9 of the hole functional layer 31 on the substrate 1 can be the dimension of the second region 31A in the second direction Y. That is, the fifth difference d5 is the difference between the dimension of the second region 31A in the second direction Y and the dimension of the first region 33A in the second direction Y. It is understood that the fifth difference d5 of this disclosure is not limited to the difference between the first region 33A and the second region 31A in the first direction X or the second direction Y. For example, the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 can also be the size of the first region 33A in other directions (not shown), and the orthogonal projection length L9 of the hole functional layer 31 on the substrate 1 can also be the size of the second region 31A in other directions (not shown). That is, the fifth difference d5 can also be the difference between the size of the second region 31A in other directions (not shown) and the size of the first region 33A in other directions (not shown), where other directions intersect with the first direction X and the second direction Y.

[0064] For example, in the third light-emitting unit 3C, the orthogonal projection length L8 of the light-emitting layer 33 on the substrate 1 can be the dimension of the first region 33A in the first direction X, and the orthogonal projection length L9 of the hole functional layer 31 on the substrate 1 can be the dimension of the second region 31A in the first direction X. That is, the fifth difference d5 is the difference between the dimension of the second region 31A in the first direction X and the dimension of the first region 33A in the first direction X. Specifically, in the third light-emitting unit 3C, the dimension of the first region 33A in the first direction X is also L8, and the dimension of the second region 31A in the first direction X is also L9.

[0065] In some embodiments, the peak value of the emission peak of the first light-emitting unit 3A is smaller than the peak value of the emission peak of the third light-emitting unit 3C.

[0066] Optionally, when the second light-emitting unit 3B is a red light-emitting unit, the third light-emitting unit 3C can be a green light-emitting unit; when the second light-emitting unit 3B is a green light-emitting unit, the third light-emitting unit 3C can be a red light-emitting unit.

[0067] like Figure 1 and Figure 7 As shown, for example, the first light-emitting unit 3A is a blue light-emitting unit, the second light-emitting unit 3B is a red light-emitting unit, and the third light-emitting unit 3C is a green light-emitting unit; correspondingly, the plurality of pixel openings 21 include a first pixel opening 21A, a second pixel opening 21B, and a third pixel opening 21C, with the first light-emitting unit 3A disposed in the first pixel opening 21A, the second light-emitting unit 3B disposed in the second pixel opening 21B, and the third light-emitting unit 3C disposed in the third pixel opening 21C.

[0068] like Figure 3 As shown, in some embodiments, in the printed first light-emitting unit 3A, the ramp-up endpoint position of the hole injection layer 311 on the sidewall of the first pixel opening 21A is lower than the ramp-up endpoint position of the hole transport layer 313 on the sidewall of the first pixel opening 21A, that is, the hole transport layer 313 completely covers the hole injection layer 311; and the minimum distance between the hole injection layer 311 and the electron transport layer 351 of the first light-emitting unit 3A is greater than 0 and not greater than 20nm.

[0069] like Figure 4As shown, in some embodiments, in the printed first light-emitting unit 3A, the end point of the ramp of the hole injection layer 311 on the sidewall of the first pixel opening 21A is higher than the end point of the ramp of the hole transport layer 313 on the sidewall of the first pixel opening 21A, that is, the hole transport layer 313 cannot cover the hole injection layer 311; and there is partial contact between the hole injection layer 311 and the electron transport layer 351 of the first light-emitting unit 3A, that is, the minimum distance between the hole injection layer 311 and the electron transport layer 351 of the first light-emitting unit 3A is 0.

[0070] It should be noted that researchers have found that the difference in the climbing ability of the hole injection layer 311 and the electron transport layer 351 of the first light-emitting unit 3A caused by the ink characteristics of the first light-emitting unit 3A means that the minimum distance between the hole injection layer 311 and the electron transport layer 351 of the first light-emitting unit 3A is no more than 20nm.

[0071] like Figure 7 , Figure 8 and Figure 9 As shown, in some embodiments, in the first light-emitting unit 3A, the shortest distance D between the hole injection layer 311 and the electron functional layer 35 is not less than 40 nm. Compared to Figure 3 and Figure 4 In the embodiment shown, by setting the shortest distance D between the hole injection layer 311 and the electronic functional layer 35 in the first light-emitting unit 3A to not less than 40nm, the display effect of the display panel can be further improved, especially the display effect when displaying at low grayscale.

[0072] Specifically, researchers found that when the light-emitting layer 33 of the first light-emitting unit 3A cannot cover the hole functional layer 31 and the minimum distance between the hole injection layer 311 and the electron transport layer 351 of the first light-emitting unit 3A is no greater than 20 nm, because the LUMO energy level of the hole injection layer 311 is greater than the LUMO energy level of the hole transport layer 313 and the potential barrier for the hole injection layer 311 to inject holes into the electron transport layer 351 is less than the potential barrier for the hole transport layer 313 to inject holes into the electron transport layer 351, it is easy for holes to leak from the hole injection layer 311 to the electron transport layer 351. This results in the leakage of holes, which cannot be used for light emission, especially in low grayscale displays where the current is low and the anode 4... If the number of holes generated is small, and holes leak from the hole injection layer 311 to the electron transport layer 351, the first light-emitting unit 3A will not be able to emit light normally or will have low luminous efficiency. However, by setting the shortest distance D between the hole injection layer 311 and the electron functional layer 35 in the first light-emitting unit 3A to not less than 40nm, the hole transport layer 313 can completely separate the hole injection layer 311 and the electron functional layer 35, thereby greatly reducing the risk of hole leakage from the hole injection layer 311 to the electron functional layer 35 and effectively avoiding the problem of the first light-emitting unit 3A not being able to emit light normally or having low luminous efficiency. This can further improve the display effect of the display panel, especially the display effect when displaying at low grayscale.

[0073] like Figure 5 , Figure 6 and Figure 7 As shown, in the second light-emitting unit 3B or the third light-emitting unit 3C, the light-emitting layer 33 can completely cover the hole functional layer 31 and separate the electron transport layer 351 from the hole functional layer 31. Therefore, it can also greatly reduce the risk of the hole injection layer 311 leaking holes to the electron functional layer 35, so as to effectively avoid the problem that the second light-emitting unit 3B or the third light-emitting unit 3C cannot emit light normally or has low luminous efficiency.

[0074] It should be noted that, as Figure 8 and Figure 9 As shown, since the first light-emitting unit 3A forms a structure that is thick in the middle and thin on both sides during the molding process, the shortest distance D between the hole injection layer 311 and the electronic functional layer 35 is actually the shortest distance D between the ramp termination position of the hole injection layer 311 and the electronic functional layer 35.

[0075] Optionally, the shortest distance D between the hole injection layer 311 and the electronic functional layer 35 can be 40nm, 41nm, 42nm, 43nm, 44nm, 45nm, 46nm, 47nm, 48nm, 49nm, 50nm, 51nm, 52nm, 53nm, 54nm, 55nm, 56nm, 57nm, 58nm, 59nm, 60nm, 61nm, 62nm, 63nm, 64nm, 65nm, 66nm, 67nm, 68nm, 69nm, or 70nm, etc. It is understood that the shortest distance D between the hole injection layer 311 and the electronic functional layer 35 is not limited to the above values, and this disclosure does not impose specific limitations on this. For example, the shortest distance D between the hole injection layer 311 and the electronic functional layer 35 can also be between any two of the above values.

[0076] like Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown, in some embodiments, a buffer space 23 is formed by the sidewall recess of the first pixel opening 21A, and the hole injection layer 311 includes a filling portion 3111 disposed in the buffer space 23. By setting the buffer space 23, the ramp height of the hole injection layer of the first light-emitting unit 3A can be limited to reduce the height difference between the middle position and the two sides of the hole injection layer 311. On the one hand, the ramp angle of the hole transport layer 313 can be reduced, which is conducive to the ramp of the hole transport layer 313 so that the hole transport layer 313 can completely cover the hole injection layer 311 and the minimum distance between the hole injection layer 311 and the electron transport layer 351 is not less than 40nm. On the other hand, the height difference between the middle position and the two sides of the hole functional layer 31 can also be reduced, which is conducive to increasing the area of ​​the light-emitting layer 33 covering the hole transport layer 313 to reduce the contact area between the hole transport layer 313 and the electron transport layer 351, thereby further reducing the risk of hole leakage from the hole transport layer 313 to the electron transport layer 351.

[0077] Optionally, the buffer space 23 is spaced apart from the anode 4, or the buffer space 23 is formed at the connection between the pixel definition layer 2 and the anode 4.

[0078] like Figure 8 and Figure 9 As shown, for example, the buffer space 23 is spaced apart from the anode 4.

[0079] Optionally, the buffer space 23 may have one, two, three or four, etc., and this disclosure does not make a specific limitation in this regard.

[0080] like Figure 9 and Figure 10As shown, for example, there are 3 buffer spaces 23, and the 3 buffer spaces 23 are spaced apart along the climbing direction Z.

[0081] Optionally, the buffer space 23 may extend through the pixel definition layer 2; or, the buffer space 23 may be designed as a blind aperture, and the present disclosure does not specifically limit the depth of the blind aperture.

[0082] Optionally, the buffer space 23 can be a square, rectangle, rhombus, triangle, circle or trapezoid, etc., and this disclosure does not specifically limit it.

[0083] Optionally, the buffer space 23 is distributed in a ring structure.

[0084] like Figure 11 and Figure 12 As shown, for example, the buffer space 23 is formed at the connection between the pixel definition layer 2 and the anode 4.

[0085] Optionally, there may be only one buffer space 23, which is arranged in a ring structure; or, there may be multiple buffer spaces 23, which are arranged in a ring structure as a whole. This disclosure does not impose any specific limitations on this.

[0086] like Figure 13 As shown, by way of example, there are multiple buffer spaces 23, and the multiple buffer spaces 23 are distributed in a ring structure.

[0087] Optionally, a buffer space 23 is provided on the sidewall of the second pixel opening 21B. By providing a buffer space 23 on the sidewall of the second pixel opening 21B, the flatness of each layer of the second light-emitting unit 3B can be improved, thereby improving the display effect of the display panel. Optionally, a buffer space 23 is provided on the sidewall of the third pixel opening 21C. By providing a buffer space 23 on the sidewall of the third pixel opening 21C, the flatness of each layer of the third light-emitting unit 3C can be improved, thereby improving the display effect of the display panel. like Figure 7 and Figure 14 As shown, in some embodiments, a step 25 is formed on the sidewall of the first pixel opening 21A. The step 25 includes a step surface 251 on the side away from the substrate 1, and the hole injection layer 311 covers the step surface 251.

[0088] Optionally, the cross-sectional shape of step 25 can be square, rectangle, rhombus, triangle, circle or trapezoid, etc., and this disclosure does not specifically limit it.

[0089] Optionally, the step 25 may be spaced apart from the anode 4 or may be located on the anode 4; this disclosure does not specifically limit this.

[0090] Optionally, a step 25 can also be provided on the sidewall of the second pixel opening 21B. This can improve the flatness of each layer of the second light-emitting unit 3B, thereby improving the display effect of the display panel. Optionally, a step 25 can also be provided on the side wall of the third pixel opening 21C. This can improve the flatness of each layer of the third light-emitting unit 3C, thereby improving the display effect of the display panel.

[0091] like Figure 16 As shown, in some embodiments, in the first light-emitting unit 3A, the thickness of the hole transport layer 313 at its center is greater than the thickness of the hole injection layer 311 at its center, and the difference between the thickness of the hole transport layer 313 at its center and the thickness of the hole injection layer 311 at its center is not less than 10 nm. By controlling the difference between the thickness of the hole transport layer 313 at its center and the thickness of the hole injection layer 311 at its center to be not less than 10 nm, the hole transport layer 313 can completely cover the hole injection layer 311, and the minimum distance between the hole injection layer 311 and the electron transport layer 351 is not less than 40 nm.

[0092] It should be noted that the center of the hole transport layer 313 is located on the axis of symmetry O of the hole transport layer 313, and the center of the hole injection layer 311 is located on the axis of symmetry O of the hole injection layer 311. The axis of symmetry O of the hole transport layer 313 coincides with or nearly coincides with the axis of symmetry O of the hole injection layer 311.

[0093] Optionally, during printing, the printing thickness of the hole injection layer 311 is reduced and the printing thickness of the hole transport layer 313 is increased so that the difference between the thickness of the hole transport layer 313 at its center and the thickness of the hole injection layer 311 at its center is not less than 10 nm. For example, when the thickness of the hole injection layer 311 at its center is 30 nm, the thickness of the hole transport layer 313 at its center is at least greater than 40 nm.

[0094] like Figure 7 , Figure 8 , Figure 11 , Figure 14 and Figure 16 As shown, the diameter of the first pixel opening 21A increases in the direction from the substrate 1 to the pixel definition layer 2.

[0095] Optionally, the aperture of the second pixel opening 21B and the aperture of the third pixel opening 21C also show an increasing trend.

[0096] like Figure 8 , Figure 11 and Figure 16 As shown, optionally, the cross-section of the first pixel opening 21A is an inverted trapezoid.

[0097] Optionally, the aperture of the second pixel opening 21B and the cross-section of the third pixel opening 21C are also inverted trapezoidal.

[0098] like Figure 7 and Figure 15 As shown, the diameter of the first pixel opening 21A decreases in the direction from substrate 1 to pixel definition layer 2. During the printing of the hole injection layer 311, the decreasing diameter of the first pixel opening 21A in the direction from substrate 1 to pixel definition layer 2 can limit the ramp height of the hole injection layer 311, thereby reducing the height difference between the middle and sides of the hole injection layer 311. On one hand, this reduces the ramp angle of the hole transport layer 313, thus improving its ramp height so that it can completely cover the hole injection layer 311 and the minimum distance between the hole injection layer 311 and the electron transport layer 351 is not less than 40nm. On the other hand, it also reduces the height difference between the middle and sides of the hole functional layer 31, thereby increasing the area covered by the light-emitting layer 33 over the hole transport layer 313, reducing the contact area between the hole transport layer 313 and the electron transport layer 351, and thus reducing the risk of hole leakage from the hole transport layer 313 to the electron transport layer 351.

[0099] Optionally, in the direction from substrate 1 to pixel definition layer 2, the diameters of the second pixel opening 21B and the third pixel opening 21C also tend to decrease. During the printing of the hole injection layer 311, the decreasing diameter of the second pixel opening 21B or the third pixel opening 21C in the direction from substrate 1 to pixel definition layer 2 can also limit the ramp height of the hole injection layer 311, thereby giving the formed second light-emitting unit 3B and third light-emitting unit 3C better flatness.

[0100] like Figure 15 As shown, optionally, the cross-section of the first pixel opening 21A is a trapezoid.

[0101] Optionally, the aperture of the second pixel opening 21B and the cross-section of the third pixel opening 21C are also trapezoidal.

[0102] According to a second aspect of this application, a display device is provided, which includes the display panel described above. This display device possesses all the beneficial effects of the display panel of this disclosure, which will not be elaborated further herein.

[0103] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0104] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0105] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0106] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A display panel, characterized in that, include: substrate; A pixel definition layer is disposed on the substrate and defines multiple pixel openings; Multiple light-emitting units are respectively disposed in multiple pixel openings. Each light-emitting unit includes a hole functional layer and a light-emitting layer. The light-emitting layer is disposed on the side of the hole functional layer away from the substrate. The plurality of light-emitting units include a first light-emitting unit. On the cross-section of the first light-emitting unit, the orthographic projection length of the hole functional layer on the substrate and the orthographic projection length of the light-emitting layer on the substrate have a first difference, which is greater than 0.

2. The display panel according to claim 1, characterized in that, The hole functional layer includes a hole injection layer and a hole transport layer. The hole transport layer is disposed between the hole injection layer and the light-emitting layer. On the cross-section of the first light-emitting unit, the orthographic projection length of the hole injection layer on the substrate and the orthographic projection length of the hole transport layer on the substrate have a second difference, wherein the first difference is greater than the absolute value of the second difference.

3. The display panel according to claim 1 or 2, characterized in that, The light-emitting unit further includes an electronic functional layer, which is disposed on the side of the light-emitting layer away from the substrate; on the cross-section of the first light-emitting unit, the orthographic projection length of the electronic functional layer on the substrate and the orthographic projection length of the light-emitting layer on the substrate have a third difference, wherein the third difference is greater than 0 and the first difference is less than the third difference.

4. The display panel according to claim 1, characterized in that, The plurality of light-emitting units further includes a second light-emitting unit. On the cross-section of the second light-emitting unit, the orthographic projection length of the light-emitting layer on the substrate and the orthographic projection length of the hole functional layer on the substrate have a fourth difference; wherein the fourth difference is greater than 0, and the first difference is greater than the fourth difference.

5. The display panel according to claim 4, characterized in that, The peak value of the emission peak of the first light-emitting unit is smaller than the peak value of the emission peak of the second light-emitting unit.

6. The display panel according to claim 1, characterized in that, The light-emitting unit further includes an electronic functional layer, which is disposed on the side of the light-emitting layer away from the substrate; the hole functional layer includes a hole injection layer and a hole transport layer, which is disposed between the hole injection layer and the light-emitting layer; wherein, in the first light-emitting unit, the shortest distance between the hole injection layer and the electronic functional layer is not less than 40 nm.

7. The display panel according to claim 6, characterized in that, The plurality of pixel openings includes a first pixel opening, and the first light-emitting unit is disposed in the first pixel opening, wherein... The sidewall of the first pixel opening is recessed to form a buffer space, and the hole injection layer includes a filling portion disposed in the buffer space; or, A step is formed on the sidewall of the first pixel opening, the step including a step surface facing away from the substrate, and the hole injection layer covers the step surface.

8. The display panel according to claim 7, characterized in that, In the first light-emitting unit, the thickness at the center of the hole transport layer is greater than the thickness at the center of the hole injection layer, and the difference between the thickness at the center of the hole transport layer and the thickness at the center of the hole injection layer is not less than 10 nm.

9. The display panel according to claim 7, characterized in that, In the direction from the substrate to the pixel definition layer, the diameter of the first pixel opening tends to increase.

10. The display panel according to claim 6, characterized in that, The plurality of pixel openings includes a first pixel opening, the diameter of which decreases in the direction from the substrate to the pixel definition layer.

11. A display device, characterized in that, Includes the display panel as described in any one of claims 1-10.

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